Cosmology's topics - tribe.net

Cosmological Model

2009-11-07T02:45:52Z

New measurements of the cosmic microwave background (CMB) – the leftover light from the Big Bang – lend further support the Standard Cosmological Model and the existence of dark matter and dark energy, limiting the possibility of alternative models of the Universe. Researchers from Stanford University and Cardiff University produced a detailed map of the composition and structure of matter as it would have looked shortly after the Big Bang, which shows that the Universe would not look as it does today if it were made up solely of 'normal matter'.

http://www.universetoday.com/2009/11/04/new-cmb-measurements-support-standard-model/

posted in Cosmology - 0 replies

My cosmos died

2009-09-30T02:58:15Z

it flickered out
without a sound
a dead shell of nothing
pistol whipped by time
cremated indifferent platitude
neutered egg-less

emptied stiff
undone colorless holes
embrace the toil
of thick knots
where you were
suffocated mass-less

no residue

unscented orgy
of unwoven blank

no eulogy

fat silent angels
circled tiredly away

perhaps worms will eat you
and go hungry.

posted in Cosmology - 1 reply

WMAP top 10

2009-08-12T21:37:25Z

http://map.gsfc.nasa.gov/

WMAP's Top Ten
NASA's Wilkinson Microwave Anisotropy Probe (WMAP) has mapped the Cosmic Microwave Background (CMB) radiation (the oldest light in the universe) and produced the first fine-resolution (0.2 degree) full-sky map of the microwave sky

WMAP definitively determined the age of the universe to be 13.73 billion years old to within 1% (0.12 billion years) -as recognized in the Guinness Book of World Records!

WMAP nailed down the curvature of space to within 1% of "flat" Euclidean, improving on the precision of previous award-winning measurements by over an order of magnitude

The CMB became the "premier baryometer" of the universe with WMAP's precision determination that ordinary atoms (also called baryons) make up only 4.6% of the universe (to within 0.1%)

WMAP's complete census of the universe finds that dark matter (not made up of atoms) make up 23.3% (to within 1.3%)

WMAP's accuracy and precision determined that dark energy makes up 72.1% of the universe (to within 1.5%), causing the expansion rate of the universe to speed up. - "Lingering doubts about the existence of dark energy and the composition of the universe dissolved when the WMAP satellite took the most detailed picture ever of the cosmic microwave background (CMB)." - Science Magazine 2003, "Breakthrough of the Year" article

WMAP has mapped the polarization of the microwave radiation over the full sky and discovered that the universe was reionized earlier than previously believed. - "WMAP scores on large-scale structure. By measuring the polarization in the CMB it is possible to look at the amplitude of the fluctuations of density in the universe that produced the first galaxies. That is a real breakthrough in our understanding of the origin of structure." - ScienceWatch: "What's Hot in Physics", Simon Mitton, Mar./Apr. 2008

WMAP has started to sort through the possibilities of what transpired in the first trillionth of a trillionth of a second, ruling out well-known textbook models for the first time.
The statistical properties of the CMB fluctuations measured by WMAP appear "random"; however, there are several hints of possible deviations from simple randomness that are still being assessed. Significant deviations would be a very important signature of new physics in the early universe.

Since 2000, the three most highly cited papers in all of physics and astronomy are WMAP scientific papers.

posted in Cosmology - 1 reply

Cosmic Distance

2009-06-09T18:11:42Z

June 8th, 2009
Astronomers Find New Way to Measure Cosmic Distances
Written by Nancy Atkinson

Using a rare type of giant Cepheid variable stars as cosmic milemarkers, astronomers have found a way to measure distances to objects three times farther away in space than previously possible. Classical Cepheids are stars that pulse in brightness and have long been used as reference points for measuring distances in the nearby Universe. But astronomers have found a way to use “ultra long period” (ULP) Cepheid variables as beacons to measure distances up to 300 million light years and beyond.

Classical cepheids are bright, but beyond 100 million light years from Earth, their signal gets lost among other bright stars, said Jonathan Bird, doctoral student in astronomy at Ohio State, who discussed his findings at the American Astronomical Society conference on Monday.

But ULPs are a rare and extra-bright class of Cepheid, which pulse very slowly.

Astronomers have also long sthought that ULP cepheids don’t evolve the same way as other cepheids. In this study, however, astronomers found the first evidence of a ULP cepheid evolving the same way as a classical Cepheid..

There are several methods for calculating the distance to stars, and astronomers often have to combine methods to indirectly measure a distance. The usual analogy is a ladder, with each new method a higher rung above another. At each new rung of the cosmic distance ladder, the errors add up, reducing the precision of the overall measurement. So any single method that can skip the rungs of the ladder is a prized tool for probing the universe.

Krzysztof Stanek, professor of astronomy at Ohio State, applied a direct measurement technique in 2006, when he used the light emerging from a binary star system in the galaxy M33 to measure the distance to that galaxy for the first time. M33 is 3 million light years from Earth.

This new technique using ULP cepheids is different. It’s an indirect method, but this initial study suggests that the method would work for galaxies that are much farther away than M33.

“We found ultra long period cepheids to be a potentially powerful distance indicator. We believe they could provide the first direct stellar distance measurements to galaxies in the range of 50-100 megaparsecs (150 million - 326 million light years) and well beyond that,” Stanek said.

Because researchers generally don’t take note of ultra long period cepheids, there are few of them in the astronomical record. For this study, Stanek, Bird and Ohio State doctoral student Jose Prieto uncovered 18 ULP cepheids from the literature.

Each was located in a nearby galaxy, such as the Small Magellanic Cloud. The distances to these nearby galaxies are well known, so the astronomers used that knowledge to calibrate the distance to the ULP cepheids.

They found that they could use ULP cepheids to determine distance with a 10-20 percent error — a rate typical of other methods that make up the cosmic distance ladder.

“We hope to reduce that error as more people take note of ULP cepheids in their stellar surveys,” Bird said. “What we’ve shown so far is that the method works in principle, and the results are encouraging.”

Bird explained why astronomers have ignored ULP cepheids in the past.

Short period cepheids, those that brighten and dim every few days, make good distance markers in space because their period is directly related to their brightness — and astronomers can use that brightness information to calculate the distance. Polaris, the North Star, is a well known and classical cepheid.

But astronomers have always thought that ULP cepheids, which brighten and dim over the course of a few months or longer, don’t obey this relation. They are larger and brighter than the typical cepheid. In fact, they are larger and brighter than most stars; in this study, for example, the 18 ULP cepheids ranged in size from 12-20 times the mass of our sun.

The brightness makes them good distance markers, Stanek said. Typical cepheids are harder to spot in distant galaxies, as their light blends in with other stars. ULP cepheids are bright enough to stand out.

Astronomers have also long suspected that ULP cepheids don’t evolve the same way as other cepheids. In this study, however, the Ohio State team found the first evidence of a ULP cepheid evolving as a more classical cepheid does.

A classical cepheid will grow hotter and cooler many times over its lifetime. In-between, the outer layers of the star become unstable, which causes the changes in brightness. ULP cepheids are thought to go through this period of instability only once, and going in only one direction — from hotter to cooler.

But as the astronomers pieced together data from different parts of the literature for this study, they discovered that one of the ULP cepheids — a star in the Small Magellanic Cloud dubbed HV829 — is clearly moving in the opposite direction.

Forty years ago, HV829 pulsed every 87.6 days. Now it pulses every 84.4 days. Two other measurements found in the literature confirm that the period has been shrinking steadily in the decades in between, which indicates that the star itself is shrinking, and getting hotter.

The astronomers concluded that ULP cepheids may help astronomers not only measure the universe, but also learn more about how very massive stars evolve.

Some of these results were reported in the Astrophysical Journal in April 2009. Since that paper was written, the Ohio State astronomers have started using the Large Binocular Telescope in Tucson, Arizona to look for more ULP cepheids. Stanek says that they’ve found a few good candidates in the galaxy M81, but those results have yet to be confirmed.

Sources: AAS, The Ohio State University

Filed under: Astronomy

http://www.universetoday.com/2009/06/08/astronomers-find-new-way-to-measure-cosmic-distances/

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Measuring Distance

2009-06-09T18:08:07Z

June 8th, 2009
New Cosmic “Yardstick” Could Help Understand Dark Energy
Written by Nancy Atkinson

A new method for measuring large astronomical distances is providing researchers with a cosmic yardstick to determine precisely how far away distant galaxies are. This could also offer a way to help determine how fast the Universe is expanding, as well as the nature of the mysterious Dark Energy that pervades the Universe. “We measured a direct, geometric distance to the galaxy, independent of the complications and assumptions inherent in other techniques. The measurement highlights a valuable method that can be used to determine the local expansion rate of the Universe, which is essential in our quest to find the nature of Dark Energy,” said James Braatz, of the National Radio Astronomy Observatory (NRAO), who spoke today at the American Astronomical Society’s meeting in Pasadena, California.

Braatz and his colleagues used the National Science Foundation’s Very Long Baseline Array (VLBA) and Robert C. Byrd Green Bank Telescope (GBT), and the Effelsberg Radio Telescope of the Max Planck Institute for Radioastronomy (MPIfR) in Germany to determine that a galaxy dubbed UGC 3789 is 160 million light-years from Earth. To do this, they precisely measured both the linear and angular size of a disk of material orbiting the galaxy’s central black hole. Water molecules in the disk act as masers to amplify, or strengthen, radio waves the way lasers amplify light waves.

The observation is a key element of a major effort to measure the expansion rate of the Universe, known as the Hubble Constant, with greatly improved precision. That effort, cosmologists say, is the best way to narrow down possible explanations for the nature of Dark Energy. “The new measurement is important because it demonstrates a one-step, geometric technique for measuring distances to galaxies far enough to infer the expansion rate of the Universe,” said Braatz.
Dark Energy was discovered in 1998 with the observation that the expansion of the Universe is accelerating. It constitutes 70 percent of the matter and energy in the Universe, but its nature remains unknown. Determining its nature is one of the most important problems in astrophysics.

“Measuring precise distances is one of the oldest problems in astronomy, and applying a relatively new radio-astronomy technique to this old problem is vital to solving one of the greatest challenges of 21st Century astrophysics,” said team member Mark Reid of the Harvard-Smithsonian Center for Astrophysics (CfA).

The work on UGC 3789 follows a landmark measurement done with the VLBA in 1999, in which the distance to the galaxy NGC 4258 — 23 million light-years — was directly measured by observing water masers in a disk of material orbiting its central black hole. That measurement allowed refinement of other, indirect distance-measuring techniques using variable stars as “standard candles.”

The measurement to UGC 3789 adds a new milepost seven times more distant than NGC 4258, which itself is too close to measure the Hubble Constant directly. The speed at which NGC 4258 is receding from the Milky Way can be influenced by local effects. “UGC 3789 is far enough that the speed at which it is moving away from the Milky Way is more indicative of the expansion of the Universe,” said team member Elizabeth Humphreys of the CfA.

Following the achievement with NGC 4258, astronomers used the highly-sensitive GBT to search for other galaxies with similar water-molecule masers in disks orbiting their central black holes. Once candidates were found, astronomers then used the VLBA and the GBT together with the Effelsberg telescope to make images of the disks and measure their detailed rotational structure, needed for the distance measurements. This effort requires multi-year observations of each galaxy. UGC 3789 is the first galaxy in the program to yield such a precise distance.

Team member Cheng-Yu Kuo of the University of Virginia presented an image of the maser disk in NGC 6323, a galaxy even more distant than UGC 3789. This is a step toward using this galaxy to provide another valuable cosmic milepost. “The very high sensitivity of the telescopes allows making such images of galaxies even beyond 300 million light years,” said Kuo.

Source: AAS

Filed under: Dark Energy, galaxies

http://www.universetoday.com/2009/06/08/new-cosmic-yardstick-could-help-understand-dark-energy/

posted in Cosmology - 0 replies

Black Rings

2009-05-06T19:12:25Z

Cosmologists ponder the puzzle of black rings
Forget black holes, astronomers are now pondering the properties of black rings

http://www.technologyreview.com/blog/arxiv/23481/

But the discovery in the last 20 years that the universe is not only expanding but accelerating away from us changes all that. If the rings can be created on the scale of the cosmological constant, which causes this accelerated expansion, then various groups have calculated that perhaps this accelerated expansion can balance the gravitational collapse, making black rings stable.

Now Masashi Kimura at Osaka City University in Japan has looked at the possibility of black rings forming in higher dimensional space. It turns out that not only are black rings possible in these conditions, but various other shapes should be stable too.

Kimura's analysis looks at how a thin black ring may have formed early in the Universe's history and later shrunk into a conventional singularity. He also looks at multi black rings--Olympic-style--and describes how these coalesce.

This and other work marks an interesting new branch of theory for black hole specialists. But cosmologists have yet to address the most important questions of all. If these objects do exist or have existed in the past, what would they look like and how might we spot them?

Dynamical Black Rings with a Positive Cosmological Constant

http://arxiv.org/PS_cache/arxiv/pdf/0904/0904.4311v2.pdf

(Dated: May 2, 2009)
Abstract
We construct dynamical black ring solutions in the five dimensional Einstein-Maxwell system
with a positive cosmological constant and investigate the geometrical structure. The solutions
describe the physical process such that a thin black ring at early time shrinks and changes into
a single black hole as time increase. We also discuss the multi-black rings and the coalescence of
them.

posted in Cosmology - 0 replies

Expansion Theorie, atracted to the rest of the Universe we can't yet see

2009-05-02T15:51:49Z

My thought on the this subject is very controversial.

Personally I can not believe in the fact that there is 1 Big Bang, and I don't mean continuous Explode contract etc..

If the Universe is infinite, then there must be a lot more than we can see.
And why believe then that our Big Bang is the only one around.
It makes more sense to me that the Big Bang is a regular happening on scale far beyond the visible Universe.

Now think of this; if we keep expanding (and apparantly accelerating) then eventually the energy of our Matter dies (Dark Matter).
Í don't know what the calculations are but I can quite wel imagine that if this happens on a large scale that we("our"Bing Bang) are (gravity wise) atracted to matter from other Big Bangs that are not within our visible reach and therefore accelerate towards the other regions of the unknown universe . No dificult calculations necessary but just simple logic I thought.

Hopefully you give me you thoughts.

Robin

posted in Cosmology - 8 replies

Boundary of the Universe

2009-04-30T07:02:11Z

My "personal idea" would be that the edge or boundary of the universe, like the center, is everywhere. That is every place in the universe is the center and also the edge or boundary. At every place the universe is expanding. We can see this expansion when we look out at distant galaxies that seem to move away from us. The distant galaxies would see us as moving away from them. It is just that the amount of space is getting bigger or expanding. This expansion of space may be happening at the quantum level of space. So quantum physics may be the place to look for the boundary of the universe. It does not seem to be out there to see in our telescopes.

posted in Cosmology - 2 replies

Before the Big Bang

2008-12-28T21:12:44Z

December 16th, 2008
More Thoughts (and now math!) On What Came Before the Big Bang
Written by Nancy Atkinson

CMB Timeline. Credit: NASA

Physicist Sean Carroll gave a wonderful talk at the June 2008 American Astronomical Society meeting about his "speculative research" on what possibly could have existed before The Big Bang. (Here's an article about Carroll's talk.) But now Carroll and some colleagues have done a bit more than just speculate about what might have come before the beginning of our Universe. Carroll, along with Caltech professor Marc Kamionkowski and graduate student Adrienne Erickcek have created a mathematical model to explain an anomaly in the early universe, and it also may shed light on what existed before the Big Bang. "It's no longer completely crazy to ask what happened before the Big Bang," said Kamionkowski.

Inflation theory, first proposed in 1980, states that space expanded exponentially in the instant following the Big Bang. "Inflation starts the universe with a blank slate," Erickcek describes. The problem with inflation, however, is that it predicts the universe began uniformly.

But measurements from Wilkinson Microwave Anisotropy Probe (WMAP) show that the fluctuations in the Cosmic Microwave Background (CMB) –the electromagnetic radiation that permeated the universe 400,000 years after the Big Bang — are about 10% stronger on one side of the sky than on the other.

WMAP map of the CMB. Credit: WMAP team

"It's a certified anomaly," Kamionkowski remarks. "But since inflation seems to do so well with everything else, it seems premature to discard the theory." Instead, the team worked with the theory in their math addressing the asymmetry, since one explanation for this "heavy-on-one-side universe" would be if these fluctuations represented a structure left over from something that produced our universe.

They started by testing whether the value of a single energy field thought to have driven inflation, called the inflaton, was different on one side of the universe than the other. It didn't work–they found that if they changed the mean value of the inflaton, then the mean temperature and amplitude of energy variations in space also changed. So they explored a second energy field, called the curvaton, which had been previously proposed to give rise to the fluctuations observed in the CMB. They introduced a perturbation to the curvaton field that turns out to affect only how temperature varies from point to point through space, while preserving its average value.

The new model predicts more cold than hot spots in the CMB, Kamionkowski says. Erickcek adds that this prediction will be tested by the Planck satellite, an international mission led by the European Space Agency with significant contributions from NASA, scheduled to launch in April 2009.

For Erickcek, the team's findings hold the key to understanding more about inflation. "Inflation is a description of how the universe expanded," she adds. "Its predictions have been verified, but what drove it and how long did it last? This is a way to look at what happened during inflation, which has a lot of blanks waiting to be filled in."

But the perturbation that the researchers introduced may also offer the first glimpse at what came before the Big Bang, because it could be an imprint inherited from the time before inflation. "All of that stuff is hidden by a veil, observationally," Kamionkowski says. "If our model holds up, we may have a chance to see beyond this veil."

Source: Caltech

posted in Cosmology - 26 replies

Dark Matter & the LHC

2008-10-15T23:55:22Z

Large Hadron Collider Could Generate Dark Matter
Written by Ian O'Neill

One of the biggest questions that occupy particle physicists and cosmologists alike is: what is dark matter? We know that a tiny fraction of the mass of the universe is the visible stuff we can see, but 23% of the Universe is made from stuff that we cannot see. The remaining mass is held in something called dark energy. But going back to the dark matter question, cosmologists believe their observations indicate the presence of dark matter, and particle physicists believe the bulk of this matter could be held in quantum particles. This trail leads to the Large Hadron Collider (LHC) where the very small meets the very big, hopefully explaining what particles could be generated after harnessing the huge energies possible with the LHC…

The excitement is growing for the grand switch-on of the LHC later this summer. We've been following all the news releases, research possibilities and some of the more "out there" theories as to what the LHC is likely to discover, but my favourite bits of LHC news include the possibility of peering into other dimensions, creating wormholes, generating "unparticles" and micro-black holes. These articles are pretty extreme possibilities for the LHC, I suspect the daily running of the huge particle accelerator will be a little more mundane (although "mundane" in accelerator physics will still be pretty damn exciting!).

David Toback, professor at Texas A&M University in College Station, is very optimistic as to what discoveries the LHC will uncover. Toback and his team have written a model that uses data from the LHC to predict the quantity of dark matter left over after the Big Bang. After all, the collisions inside the LHC will momentarily recreate some of the conditions at the time of the birth of our Universe. If the Universe created dark matter over 14 billion years ago, then perhaps the LHC can do the same.

Should Toback's team be correct in that the LHC can create dark matter, there will be valuable implications for both particle physics and cosmology. What's more, quantum physicists will be a step closer to proving the validity of the supersymmetry model.

"If our results are correct we now know much better where to look for this dark matter particle at the LHC. We've used precision data from astronomy to calculate what it would look like at the LHC, and how quickly we should be able to discover and measure it. If we get the same answer, that would give us enormous confidence that the supersymmetry model is correct. If nature shows this, it would be remarkable." - David Toback

So the hunt is on for dark matter production in the LHC… but what will we be looking for? After all dark matter is predicted to be non-interacting and, well, dark. The supersymmetry model predicts a possible dark matter particle called the neutralino. It is supposed to be a heavy, stable particle and should there be a way of detecting it, there could be the opportunity for Toback's group to probe the nature of the neutralino not only in the detection chamber of the LHC, but the nature of the neutralino in the Universe.

"If this works out, we could do real, honest to goodness cosmology at the LHC. And we'd be able to use cosmology to make particle physics predictions." - Toback

Source: Physorg.com

posted in Cosmology - 3 replies

Dark Matter Missing in Cosmic Voids

2008-08-19T03:30:22Z

August 17th, 2008del.icio.us Digg Reddit StumbleUpon
Dark Matter is Missing From Cosmic Voids
Written by Nancy Atkinson

Map of distribution of galaxies. Credit: M. Blanton and the SDSS.
Cosmic voids really are devoid of matter. Astronomers have found that even the pervasive 'dark matter' which accounts for about 80% of the mass of the universe is not present in these voids, which are areas of vast emptiness in space that can be tens of millions of light-years across. "Astronomers have wondered for a quarter-century whether these voids were 'too big' or 'too empty' to be explained by gravity alone," said University of Chicago researcher Jeremy Tinker, who led the new study using data from the Sloan Digital Sky Survey II (SDSS-II). "Our analysis shows that the voids in these surveys are exactly as big and as empty as predicted by the 'standard' theory of the universe."

The largest 3-dimensional maps of the universe show that galaxies lie in filamentary superclusters interlaced by cosmic voids that contain few or no bright galaxies. Researchers using SDSS-II and the
Two-Degree Field Galaxy Redshift Survey (2dFGRS) have concluded that these voids are also missing the "halos" of invisible dark matter that bright galaxies reside in.

A central element of the standard cosmological theory is cold dark matter, which exerts gravity but does not emit light. Dark matter is smoothly distributed in the early universe, but over time gravity pulls it into filaments and clumps and empties out the spaces between them. Galaxies form when hydrogen and helium gas falls into collapsed dark matter clumps, referred to as "halos," where it can form luminous stars.

But astronomers were not sure if the areas that are devoid of galaxies were also devoid of dark matter, or if the dark matter was there, but for some reason stars just didn't form in these voids.
The research team used bright galaxies to trace the structure of dark matter and compared it with computer simulations to predict the number and sizes of voids.
Princeton University graduate student Charlie Conroy measured the sizes of voids in the SDSS-II maps. "When we used galaxies brighter than the Milky Way to trace structure, the biggest empty voids we found were about 75 million light years across," said Conroy. "And the predictions from the simulations were bang-on."

The sizes of voids are ultimately set, Conroy explained, by the small variations in the primordial distribution of dark matter, and by the amount of time that gravity has had to grow these small variationsinto large structures.

The agreement between the simulations and the measurements holds for both red (old) and blue (new) galaxies, said Tinker. "Halos of a given mass seem to form similar galaxies, both in numbers of stars and in the ages of those stars, regardless of where the halos live."

Tinker presented his findings today at an international symposium in Chicago, titled "The Sloan Digital Sky Survey: Asteroids to Cosmology." A paper detailing the analysis will appear in the September 1 edition of The Astrophysical Journal, with the title "Void Statistics in Large Galaxy Redshift Surveys: Does Halo Occupation of Field Galaxies Depend on Environment?"

News Source: SDSS and The Ohio State University

http://www.universetoday.com/2008/08/17/dark-matter-is-missing-from-cosmic-voids/

posted in Cosmology - 0 replies

New Evidence of Dark Energy

2008-08-02T07:25:48Z

http://www.universetoday.com/2008/07/30/astronomers-find-new-evidence-for-dark-energy/

July 30th, 2008del.icio.us Digg Reddit StumbleUpon
Astronomers Find New Evidence for Dark Energy
Written by Nancy Atkinson

Dark Energy's stretching effect. Credit: U of Hawaii
A team of astronomers has found what they say is the clearest detection to date of dark energy in the universe. Scientists at the University of Hawaii compared an existing database of galaxies with a map of the cosmic microwave background radiation (CMB), and were able to detect dark energy's effect on vast cosmic structures such as superclusters of galaxies, where there is a high concentration of galaxies, and supervoids, areas in space with a small number of galaxies. “We were able to image dark energy in action, as it stretches huge supervoids and superclusters of galaxies,” said Dr. István Szapudi said, from U of Hawaii's Institute for Astronomy.

The discovery in 1998 that the universe was actually speeding up in its expansion was a surprise to astronomers. Dark energy refers to the fact that something must fill the vast reaches of mostly empty space in the Universe in order to be able to make space accelerate in its expansion. Dark energy works against the tendency of gravity to pull galaxies together and so causes the universe’s expansion to speed up.But the nature of dark energy and why it exists is one of the biggest puzzles of modern science.
The team from the University of Hawaii made the discovery by measuring the subtle imprints that superclusters and supervoids leave in microwaves that pass through them. Superclusters and supervoids are the largest structures in the universe.
“When a microwave enters a supercluster, it gains some gravitational energy, and therefore vibrates slightly faster,” explained Szapudi. “Later, as it leaves the supercluster, it should lose exactly the same amount of energy. But if dark energy causes the universe to stretch out at a faster rate, the supercluster flattens out in the half-billion years it takes the microwave to cross it. Thus, the wave gets to keep some of the energy it gained as it entered the supercluster.”
“Dark energy sort of gives micro waves a memory of where they’ve been recently,” postdoctoral scientist Mark Neyrinck said.

Comparing superclusters (red circles) and supervoids (blue circles) with the CMB. Credit: U of Hawaii
When the team compared galaxies against the CMB, they found that the microwaves were a bit stronger if they had passed through a supercluster, and a bit weaker if they had passed through a supervoid.
“With this method, for the first time we can actually see what supervoids and superclusters do to microwaves passing through them,” said graduate student Benjamin Granett.
The signal is difficult to detect, since ripples in the primordial CMB are larger than the imprints of individual superclusters and supervoids. To extract a signal, the team averaged together patches of the CMB map around the 50 largest supervoids and the 50 largest superclusters that they detected in extremely bright galaxies drawn from the Sloan Digital Sky Survey, a project=2 0that mapped the distribution of galaxies over a quarter of the sky.
The astronomers say there is only a one in 200,000 chance that the evidence they detected would occur by chance.
Original News Source: U of Hawaii press release

posted in Cosmology - 9 replies

Dark Energy Survey

2008-06-25T22:01:37Z

Huge Camera to Observe Dark Energy
Written by Nancy Atkinson

" ...
The Dark Energy Survey (DES) camera will map 300 million galaxies using the Blanco 4-meter telescope - a large telescope with new advanced optics at Chile’s Cerro Tololo Inter-American Observatory. This instrument will consist of an extremely red sensitive 500 Megapixel camera, with a 1 meter diameter, 2.2 degree field of view prime focus corrector, and a data acquisition system fast enough to take images in 17 seconds.
Creating this huge map of the galaxy will enable astronomers to measure the dark energy far more precisely than current observations. Professor Ofer Lahav, who leads the United Kingdom DES Consortium said, "Dark Energy is one of the biggest puzzles in the whole of Physics, going back to a concept proposed by Einstein 90 years ago. The DES observations will tell us if Einstein was right or if we need a major shift in our understanding of the universe.”

The glass for the five lenses was manufactured in the US. In France the lenses will be polished to a smoothness level of one millionth of a centimeter.

After, polishing, the lenses will be sent to the telescope in Chile. Observations are scheduled to begin in 2011, continuing until 2016.

The team’s goals are to extract cosmological information on dark energy from counting galaxy clusters and the spatial distribution of clusters, and measuring the redshift of galaxies and supernovae.

The Science and Technology Facilities Council (STFC) is providing support for the Dark Energy Survey (DES) collaboration, which involves over 100 scientists from the US, UK, Spain and Brazil. "

posted in Cosmology - 0 replies

Dark Energy

2008-06-07T19:22:37Z

http://www.nytimes.com/2007/03/11/magazine/11dark.t.html

posted in Cosmology - 5 replies

WMAP Neutrinos

2008-05-14T20:53:24Z

Cosmic Neutrinos, the End of the Dark Ages, and Inflation: 5 Years of WMAP Data
Written by Fraser Cain

We now know the Universe is around 13.7 billion years old. But just a few years ago, cosmologists had no idea, putting the range around 10-20 billion years old - some even thought it could be 100 billion years old. We can thank NASA's Wilkinson Microwave Anisotropy Probe for giving us the concrete answer. And now, NASA released 5 years of data collection, telling astronomers more about the earliest moments in the Universe, the background sea of cosmic neutrinos and the end of the Dark Ages.

WMAP looks at the Universe with microwave eyes. It may sound like a strange wavelength to use when witnessing the highest energy event ever - the aftermath of the Big Bang. But there's a trick, over the billions of years of time, the Universe has been expanding. Radiation has had its wavelengths stretched out across the billions of light-years of distance and expansion. The visible light after the Big Bang has become a diffuse glow of microwaves in all directions.
Astronomers use WMAP to study the subtle temperature variations in this microwave background radiation to understand what the Universe looked like at the very beginning.
This 5th anniversary release of data is the icing on the cake, with some significant new findings.
First up, WMAP found evidence for a background sea of cosmic neutrinos that permeate the background of the Universe. These almost weightless sub-atomic particles zip around at nearly the speed of light. In fact, there are millions passing through your body right now, blasted out from the Sun. They don't interact with anything, so they don't cause any harm. In fact, a neutrino could probably make it through several light years of solid lead without being stopped.
So, in addition to the solar neutrinos there seem to be a sea of background neutrinos, generated during the Universe's early development.

posted in Cosmology - 4 replies

Time running out

2008-05-14T14:44:05Z

http://breakingnews.ie/world/mheykfkfeyau/

Bizarre theory suggests time may be running out
18/12/2007 - 18:04:32

Time may literally be running out – and could one day vanish altogether, according to a bizarre new theory.

The suggestion has been put forward to explain a cosmological mystery that has baffled scientists.

A decade ago, measurements of the light from distant exploding stars showed the universe to be expanding at an accelerating rate.

Physicists assumed that a kind of anti-gravitational force must be driving the galaxies apart, and gave it the name “dark energy”.

However, to this day no-one has been able to say what dark energy is or where it comes from.

The new theory from Professor Jose Senovilla, at the University of the Basque Country in Bilbao, Spain, offers a radical alternative idea.

He believes there is no such thing as dark energy. Instead, he says we have been fooled into thinking the expansion of the universe is accelerating because time itself is slowing down.

At our local everyday level, the change would be imperceptible.

But it would be obvious from cosmic scale measurements tracking the course of the universe over billions of years.

Astronomers work out the speed of the universe’s expansion from the frequency of light emitted by certain types of supernovae, or exploding stars.

However, these measurements depend on our current perception of time, says Prof Senovilla.

If time has been slowing down, and clocks are now running more slowly than they did long ago, it would appear from our perspective as if things have been speeding up. Looking back over billions of years, galaxies would seem to be travelling away from each other faster and faster at various intervals since the Big Bang.

“Our calculations show that we would think that the expansion of the universe is accelerating,” said Senovilla.

His idea is based on string theory concepts which allow dimensions of space and time to switch from one to another.

If our single time dimension was changing into a new space dimension, it would produce just such an effect.

After billions of years, time would eventually disappear altogether.

“Then everything will be frozen, like a snapshot of one instant, forever,” Prof Senovilla told New Scientist magazine. “Our planet will be long gone by then.”

Prof Gary Gibbons, a cosmologist at Cambridge University, is drawn to the idea.

“We believe that time emerged during the Big Bang, and if time can emerge, it can also disappear – that’s just the reverse effect,” he said.

posted in Cosmology - 14 replies

10th "planet" found farther and larger than Pluto

2008-05-14T14:40:56Z

http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/07/30/MNGTNE0G9L1.DTL

Astronomers announced with excitement Friday they had discovered what they call the solar system's 10th planet -- a shining object, much larger than distant Pluto, that is orbiting the sun more than 9 billion miles from Earth.

It is by far the largest and most distant object ever detected in the outermost reaches of the solar system, and the announcement is certain to stir up controversy among other astronomers who will argue that because it is so far off, it is not entitled to be called a planet at all.

posted in Cosmology - 4 replies

Inflation theory and gravitational radiation

2008-04-17T14:37:08Z

Inflation Theory Takes a Little Kick in the Pants
Written by Nancy Atkinson

Inflation theory proposes that the universe underwent a period of exponential expansion right after the Big Bang. One of the key predictions of inflation theory is the presence of a particular spectrum of "gravitational radiation"—ripples in the fabric of space-time that are really hard to detect but thought to exist. But a team of researchers has now found that gravitational radiation can be produced by a mechanism other than inflation. So this type of radiation, if eventually detected, won’t provide the conclusive evidence for inflation theory that was once was thought to be a certainty.

"If we see a primordial gravitational wave background, we can no longer say for sure it is due to inflation," said noted astronomer Lawrence Krauss, from Case Western Reserve University.

Inflation theory first was proposed by cosmologist Alan Guth in 1981 as a means to explain some features of the universe that had previously baffled astronomers, such as why the universe is so close to being flat and why it is so uniform. Today, inflation remains the best way to theoretically understand many aspects of the early Big Bang universe, but most of the theory’s predictions are somewhat vague enough that even if the predictions were observed, they probably wouldn’t provide a clear-cut confirmation of the theory.

But gravitational radiation was considered one of the key predictions of inflation theory, and detection of this spectrum was regarded among physicists as "smoking gun" evidence that inflation did in fact occur, billions of years ago.

Gravitational radiation is a prediction of Einstein's Theory of General Relativity. According to the theory, whenever large amounts of mass or energy are shifting around, it disrupts the surrounding space-time and ripples emanate from the region where the shift occurs. These ripples aren’t easily detected, but there is one experiment designed to look directly for this radiation, the Laser Interferometer Gravitational Wave Observatory (LIGO) in Livingston, Louisiana. The upcoming Planck Mission, set to launch in 2009 will look for it indirectly by looking at the cosmic microwave background.

Until now it was widely believed that detecting gravitational radiation in the form of polarized light from the CMB would confirm inflation theory, since it was thought inflation would be the only way this radiation could be produced. But Krauss and his team have raised the issue of whether this radiation can be unmistakably tied to inflation.

Krauss’s team proposes that a phenomenon called "symmetry breaking," can also produce gravitational radiation. Symmetry breaking is a central part of fundamental particle physics, where a system goes from being symmetrical to a low energy state that is not symmetrical. Krauss’s explanation is that a "scalar field" (similar to an electric or magnetic field) becomes aligned as the universe expands. But as the universe expands, each region over which the field is aligned comes into contact with other regions where the field has a different alignment. When that happens the field relaxes into a state where it is aligned over the entire region and in the process of relaxing it emits gravitational radiation.

This is all fairly confusing, but the sweetened condensed version is that if gravitational radiation is ever detected, that event won’t necessarily verify inflation theory. Therefore, whether inflation theory can ever be confirmed remains to be seen.

Krauss’s paper "Nearly Scale Invariant Spectrum of Gravitational Radiation from Global Phase Transitions" is published in the Aprill 2008 Physical Review Letters.

Original News Source: Case Western Reserve University press release

posted in Cosmology - 0 replies

Collision of galaxies exposes Dark Matter, astronomers say

2008-02-09T20:43:56Z

Collision of galaxies exposes 'dark matter,' astronomers say
Gravity from invisible stuff distorts Hubble's view of objects beyond

David Perlman, Chronicle Science Editor
Wednesday, May 16, 2007

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/05/16/MNGGTPRID11.DTL

If it weren't for the powerful gravity in some ghostly unknown stuff that surrounds us, everything and everybody in our universe would fly apart in a flash.

The mysterious stuff is called "dark matter," and the grip of its gravity holds all the stars and planets, people and atoms exactly where they belong, just the way the laws of physics dictate.

Now astronomers using the Hubble Space Telescope reported Tuesday that they have discovered convincing new evidence for the existence of dark matter -- in a huge ring circling the remains of two clusters of distant galaxies that clashed in a monstrous collision nearly 2 billion years ago.

The remains of those galaxies are about 5 billion light-years away, but the gravity in the dark matter around them has so distorted the telescope's view of objects beyond them that the astronomers say their complex calculations enabled them to determine the shape of the ring and its mysterious contours. "We think this is the strongest evidence yet for the existence of dark matter," said astrophysicist M. James Jee of Johns Hopkins University in a phone conference with reporters from the Space Telescope Science Institute, the Hubble's ground headquarters near Baltimore.

"This is the first time we have detected dark matter as having a unique structure that is different both from the gas and the galaxies in the cluster," he said.

His team's formal report will be published June 1 in the Astrophysical Journal.

posted in Cosmology - 28 replies

watever

2008-01-19T08:45:11Z

collision
expansion
swirly things
contraction
expansion
collision of swirly things
partial expansion
contraction
expansion of swirly things
silence

posted in Cosmology - 1 reply

What bang?

2008-01-01T18:15:52Z

Is there a new TV show called the big bang?
I do not really keep up with TV.

posted in Cosmology - 10 replies

Carl Sagan Was an Avid Pot -Smoker

2007-08-10T06:05:04Z

When you're talking about scientists who acheived rock star status in the 2nd half of the 20th century, the late astronomer and biologist Carl Sagan is right up there with Steven Hawking. His Cosmos (1980) is one of the most popular science books ever written, planting itself on the New York Times bestseller list for 70 weeks and being perpetually in print ever since. It was a companion for the PBS television series of the same name -which, along with numerous Tonight Show appearances - introduced Sagan and his emphatically stated phrase "billions and billions" into pop culture. His sole novel, "Contact" was turned into a love-it-orhate-it movie starring Jodie Foster as an erstwhile scientist searching for extraterrestrial life., with Matthew McConaughey as a new age flake who, inevitably, makes his own form of contact with her.
Besides his pop-culture credentials, Sagan was pals with numerous Nobel Prize winners while still in college, picked up a Pulitzer prize for his book "Dragons of Eden".and consulted with NASA, MIT, Cornell and RAND. He designed the human races postcards to any aliens that might be out there - the plaque on the pioneer space probes and the record on the Voyager probes.
So it might come as a bit of a surprise that Sagan was an avid smoker of Marijuana - some might even call him a pothead.
In his definitive biography of the celebrity scientist, Keay Davidson reveals that Sagan started toking regularly in the earlly 1960's - and that "Dragons of Eden" - which won the Pulitzer - "was obviously witten under the influence of Marijuana". Davidson says of Sagan:
He believed the drug enhanced his creativity and insights. His closest friend of 3 decades, Harvard Psychiatry Professor Lester Grinspoon, a leading advocate of the decriminalization of Marijuana, recalls an incident in the 1980's when one of his California admirers mailed him, unsolicited, some unusually high quality pot. Grinspoon smoked the joints with Sagan and his wife, Anne Druyan. Afterward, Sagan said "Lester, I know you've only got one left, but could I have it? I've got some serious work to do tomorrow and sure could use it."
Perhaps letting Sagan bogart the pot was Grinspoon's way of returning a favor, since Sagan had contributed an essay to Marijuana Reconsidered - Grinspoon's classic 1971 book on the benefits and low risk of reefer. For almost 3 decades, the author of this ode to Mary Jane was anonymous, but in 1999 Grinspoon revealed that "Mr. X"" was Carl Sagan.
In the essay, Sagan wrote that weed increased his appreciation of art, food, sex and childhood memories and gave him insight into scientific and social matters:
I can remember one occasion, taking a shower with my wife while high, in which I had an idea on the origins and invalidities of racism in terms of Gaussion distribution curves. It was a point obvious (sic) in a way, but rarely talked about. I drew curves in shapes on the shower wall and went in to write the idea down. One idea led to another and at the end of an hour of extremely hard work, I found that I had written 11 short essays on a wide range of social, political, philosphical and human biological topics......I have used them in university commecement addresses, public lectures and in my books.
The stauchly atheistic/humanistic Sagan comes perilously close to mysicism in some passages:
I do not consider myself a religious person in the usual sense, but there is a religious aspect to some highs. The heightened sensitivity in all areas gives me a feeling with my surroundings, both animate and inanimate. Sometimes a kind of existential perception of the absurd comes over me and I see with awful certainty the hypocrisies and posturing of myself and my fellow men and at other times, there is a different sense of the absurd, a playful a whimsical awareness....I am convinced that there are valid levels of perception available with cannabis (and probably other drugs) which are, through the defects of our society and our educational system unavailable without such drugs. Such a remard applies not only to self-awareness and to intellectual pursuits, but also to perceptions of real people, a vastly enhanced sensitivity to facial expressions, intonations and choice of words which sometimes yields a rapport so close it's as if two people are reading each other's minds.

posted in Cosmology - 2 replies

New Tribe

2007-05-20T09:00:04Z

http://tribes.tribe.net/quantum-gravity

posted in Cosmology - 0 replies

Largest Supernova ever discovered

2007-05-15T20:08:11Z

http://www.usnews.com/usnews/news/articles/070513/21supernova.htm

Video of discussion about supernova:
http://bloggingheads.tv/video.php?id=273&cid=1491

posted in Cosmology - 0 replies

Whaddya make of this?

2007-05-03T16:45:39Z

Hey folks. I just joined this tribe and thought I'd give it a whirl by opening with this article:

http://www.space.com/scienceastronomy/070501_scietues_futureuniverse.html

"...in the far future, radiation--including heat, light and all other forms--will vanish faster than it can be replenished through the decay of matter into component protons, neutrons and electrons"

Am I the only one who has trouble accepting this concept? My understanding is that this universe is one of many and a result of something prior (another universe or something). Up until now, I figured the "end" of this universe would be the "start" of a new one (or something similar). But how can it have any end whatsoever if all you're left with is fast, cold matter?

Certainly someone here understands this new theory (and its consequences or implications) than myself. So, enlighten us.

Thanks for your opinions and explanations

:)
Feiruz

posted in Cosmology - 8 replies

What is the universe expanding into?

2007-05-01T18:16:29Z

The simple answer is time. As we look out into the universe we see distant galaxies all moving away from us like we are the center of the universe. We are not unique because every place in the universe looks like it is the center. If we could go a billion light years from here in any direction it would also look like the center. The universe has no single center or any edge away from that center. There is no outside for the universe to expand into. In a way, every point in the universe today is the place where the universe began, the center. Also in a way, every point in the universe is the edge where the universe is expanding. The edge is not somewhere out there. The edge, like the center, is everywhere. The universe is larger today than it was in the past and it will be larger in the future. The edge that is expanding is every point in the universe and the dimension that it is expanding into is the future. So the simple answer to, what is the universe expanding into, is that the universe is expanding into time.

posted in Cosmology - 11 replies

The new frontier in cosmology

2007-04-23T18:55:11Z

http://www.sciam.com/article.cfm?articleId=0002BE5A-D608-152F-960883414B7F0123

Check it out. Epoch of Reionization is a hot topic, and will be more so in the next few years!

posted in Cosmology - 3 replies

10 dimensions explanation video - used in string theory

2007-02-14T02:16:57Z

10 dimension explanation video - PART 1

http://www.youtube.com/watch?v=JkxieS-6WuA

10 dimension explanation video - PART 2

http://www.youtube.com/watch?v=ySBaYMESb8o

posted in Cosmology - 0 replies

Milky Way's dark matter modelled in best detail yet

2006-11-22T03:20:55Z

Our galaxy could be surrounded by a vast swarm of invisible companions. These giant clouds of dark matter – representing the failed seeds of galaxy formation – may be detected with a telescope to be launched next year.
Dark matter makes up about 82% of all the matter in the universe, although nobody knows what it actually is. Small clouds of the stuff are thought to have coalesced after the big bang, and then gradually merged together. When enough dark matter is gathered into a huge "halo", it attracts ordinary gas to form stars, and so becomes a galaxy.
Now, scientists led by Jürg Diemand of the University of California in Santa Cruz, US, have modelled this process in more detail than ever before, following the fate of more than 200 million cloudlets as they come together into a halo about the same size as that of our Milky Way.
Such a detailed simulation requires a lot of computing power. "It's at the limit of what current supercomputers can do," Diemand told New Scientist.
The result is a fascinating animation of galactic birth (4.6 MB MPEG version). (See link below)
Missing galaxiesIt shows there should be at least 10,000 separate "subhaloes" of dark matter within the overall galactic halo, each at least a few thousand light years across.
And a fair number of these galactic seeds should have germinated. About 120 clumps are large enough to have attracted some gas of their own to become dwarf galaxies – yet astronomers have seen only 15 dwarf companions of the Milky Way. What happened to the rest?
A relatively radical solution is that dark matter has some property that prevents it from forming dense clumps. For example, it might be unexpectedly hot, and therefore hard to compress. "But at the moment, the consensus is you don't need to go to these extremes," says Diemand.
There are other explanations. It may be that most of the subhaloes were sterilised by ultraviolet light from the earliest stars. That heated up intergalactic gas, making it more difficult to capture. And perhaps supernova explosions blasted gas out of many of the nascent dwarf galaxies, ending their brief lives.
Gravitational lensSpotting these dark clouds will be a challenge. If astronomers are lucky, then dark matter particles behave in such a way that they annihilate each other when they collide.
In that case, they would emit gamma rays, and the gamma-ray glow of our dark matter companions might be detectable with NASA's Gamma-ray Large Area Space Telescope, due for launch in 2007.
Otherwise, the clumps might show up as flaws in a gravitational lens. The dark matter haloes of fairly distant galaxies can sometimes focus the light from objects behind them.
The haloes bend it by the force of gravity rather than the refraction of an ordinary lens, often magnifying and multiplying the images of very distant sources. If the haloes are clumpy, that should slightly alter the images produced.

Original link with a cool animation: http://space.newscientist.com/article.ns?id=dn10636&feedId=astronomy_rss20

posted in Cosmology - 0 replies

Please Help

2006-11-19T23:22:34Z

If a large square glass container were moving in a vacuum uniformely at a velocity of 100m.s., and a ray of light passed from the back of the container (Velocity 1 which would be the speed of light constant, C) through the container (Velocity 2?) and then through the front end (Velocity 3?).
What would "Velocity 2" and "Velocity 3" be?
I will try and draw a diagram.
...................___________
..................|......................|
..................|......................|
-->-C--->--|----"2"---->---- |---"3"->
..................|......................|
..................|__________ |

+ The effect of the actual glass on the light is to be ignored.
+ One answer for a observer on the ground and one answer for an observer in the glass container.
+ The container's atmosphere is a vacuum.

I know this a basic question, but I'm still learning.

posted in Cosmology - 1 reply

Scientists Saved the Big Bang Theory

2006-11-07T23:45:51Z

According to the Big Bang theory, the universe emerged from a tremendously dense and hot state about 13.7 billion years ago. The theory predicts that during the later stages of this process, hydrogen and helium were produced. The predicted numbers are about 10 percent helium-4, 0.001 percent of helium-3 and the rest hydrogen.

However, later on, low mass stars that eventually turn into red giants produce more helium and the amount of helium-3 should have increased to about 0.01 percent. But scientists have only observed about 0.001 percent of helium-3 in the interstellar space. So where did that helium-3 go?

"The trouble is, low mass stars (about one to two times the size of our sun) also make Helium 3 as a side product of burning the hydrogen in their cores. It's been thought that when the star becomes a giant it mixes the helium 3 to its surface and, near the end of its life, spews the helium 3 into space just before it becomes a planetary nebula," said Professor John Lattanzio from Monash's School of Mathematical Sciences and Director of the Centre for Stellar and Planetary Astrophysics. "But there are inconsistencies with the amount of Helium 3 predicted to be in the universe and the amount that's actually there; there's much less than expected."

The missing helium-3 raised doubts about the validity of the Big Bang theory. The amount of observed helium-3 seemed to
imply that all the helium-3 was coming from stars. However, the new study of Lattanzio's team has now showed that the opposite is true – the stars don't actually release the helium-3.

Other scientists have previously theorized that maybe the helium-3 was being destroyed due to the high speed rotation of the red giants. But it seemed unlikely that the stars were engaged in such a high speed rotation. Moreover, computer models that included rotation showed that that didn't solve the problem.

Lattanzio and his colleagues have now showed that the high speed rotation hypothesis is not necessary because the helium-3 is destroyed in the gaseous mixing that occurs in the stars. They have used computer models to understand the conditions near the end of the star's life and created a 3D simulation of the occurring hydrodynamic instabilities. This study is plasma physics at its best.

The image above shows what happens deep in the interior of a red giant. The star is far from being homogenous. There are hydrogen rich "clouds" (red) floating above the burning hydrogen shell (blue). The model revealed that the energy production rate in the burning shell exceeds that of the Sun by more than 100 times. Initially, the helium-3 and helium-4 are floating around forming a relatively homogenous atmosphere, but the energy release from the burning shell changes everything. The energy release converts the helium-3 into helium-4 and hydrogen. This is how the hydrogen "clouds" are formed and how the surplus of helium-3 disappears. The difference between helium-3 and helium-4 is that the first has only one neutron inside its nucleus while the second has two neutrons (besides the two protons that both have).

The collaborators of professor Lattanzio are Dr Peter Eggleton and Dr David Dearborn from the Lawrence Livermore National Laboratories in the US. Their findings were published in yesterday's issue of the international journal Science.

"When we looked at this in 3D we found this hydrodynamic instability caused mixing and destroyed the helium-3 so that none was released into space," Professor Lattanzio said. "This apparent problem with the Big Bang has been solved – the helium-3 in the universe comes from the Big Bang and low mass stars, although they produce helium-3, do not release any into the universe because they destroy it."

"This confirms how elements evolved in the universe and makes it consistent with the Big Bang," said Dearborn. "The previous one-dimensional model did not recognize the instability created by burning helium-3."

"Prior to our work, it was perceived that the helium-3 in the envelope was largely indestructible, and would be blown off later into space, thus enriching the interstellar medium and causing the conflict with the Big Bang," added Eggleton. "What we find is that helium-3 is unexpectedly destructible, by a mixing process driven by a phenomenon that has been ignored so far."

Credit: Lawrence Livermore National Laboratories

Original Link: http://news.softpedia.com/news/Scientists-Saved-the-Big-Bang-Theory-38865.shtml

posted in Cosmology - 1 reply

Cool Video from JPL

2006-10-31T16:22:26Z

Here's the link:
http://www.jpl.nasa.gov/videos/spitzer/spitzer20061030/

posted in Cosmology - 1 reply

"Star Explosion is Suprisingly Neat & Tidy"

2006-10-28T20:48:11Z

Jeanna Bryner
Staff Writer
SPACE.com
Fri Oct 27, 11:15 AM ET

Stars don't always rip apart in violent explosions. Some blow up in an orderly fashion.

A star named Cassiopeia A blew up in such a tidy manner that it retained much of its original onion-like layering [image: http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=061026_casa_star_02.jpg&cap=A+false-color+image+taken+by+Spitzer.+The+faint+blue+glow+surrounding+Cassiopeia+A+is+material+energized+by+the+faster-moving+forward+shock+wave.+Green%2C+yell ]

"We've found new bits of the 'onion' layers that had not been seen before," said co-researcher Lawrence Rudnick of the University of Minnesota. "This tells us that the star's explosion was not chaotic enough to stir its remains into one big pile of mush."

The work was led by Jessica Ennis, also of the University of Minnesota.

Heated explosion

Cassiopeia A (Cas A) is a supernova remnant within our Milky Way Galaxy, located 10,000 light-years away in the constellation Cassiopeia. The original star, about 15 to 20 times more massive than our Sun, died in a cataclysmic supernova.

Like all mature, massive stars, the Cas A star was once neat and tidy, consisting of concentric shells made up of various chemical elements: The outer layers held lighter elements, such as hydrogen, the middle layers were lined with heavier elements like neon, and its core was stacked with the heaviest elements such as iron.

Until now, scientists couldn't figure out what happened to the star when it ripped apart. One idea purported the star exploded in a more or less uniform fashion, flinging its layers out in successive order. If this were the case, those layers should be preserved in the expanding debris. While previous observations revealed parts of some of these layers, others were missing.

Missing pieces

NASA's infrared Spitzer Space Telescope gave astronomers a never-seen-before look at the missing pieces.

'Spitzer has essentially found key missing pieces of the Cassiopeia A puzzle," Ennis said.

When a massive star explodes, it creates two types of shock waves. The forward shock wave darts out quickest, and, in the case of Cas A, is now traveling at supersonic speeds up to 4,600 miles per second (7,400 kilometers per second). When the forward wave slams into ejected stellar material, a reverse shock wave is created that tags along behind the forward shock wave at slightly slower speeds [video].

Stellar material thrown out fastest hits the shock wave sooner, giving it more time to heat up to scorching temperatures that could be detected with X-ray and visible-light telescopes. More sluggish chunks hit the shock wave later so they are cooler and radiate infrared light that couldn't be observed until Spitzer came along.

The lagging chunks are made up of gas and dust containing neon, oxygen and aluminum - elements from the middle layers of the original star.

The study will be detailed in the Nov. 20 issue of the Astrophysical Journal.

posted in Cosmology - 0 replies

Russia can repel asteroids to save Earth: official

2006-10-27T00:39:10Z

MOSCOW (AFP) - Russia is prepared to repel asteroids to save Earth "if necessary," deputy head of the Russian space agency Viktor Remishevsky reportedly said.

"If necessary, Russia's rocket-manufacturing complex can create the means in space to repulse asteroids threatening Earth," Remishevsky told the ITAR-TASS news agency, without giving further details.

The official stressed that saving Earth from the threat of asteroids demanded international cooperation.

"Above all, space research institutions, telescopes, and the infrastructure of the Russian Academy of Sciences should warn about the threat of asteroids falling to Earth," Remishevsky said.

According to Russia's Institute of Applied Astronomy, about 400 asteroids and over 30 comets currently present a potential threat to the planet.

The institute's specialists are particularly concerned about an asteroid known as Number 2907, a kilometer-wide chunk of space rock that they believe "with a large degree of certainty" will strike the Earth on December 16, 2880.

Original link: http://news.yahoo.com/s/afp/20061024/sc_afp/russiaspacemilitary_061024172806

posted in Cosmology - 12 replies

Planet-Finding by Numbers

2006-10-20T06:51:24Z

Feature October 18, 2006

Planet-Finding by Numbers

More than a decade after the first planets beyond our solar system were found, astronomers have discovered about 200 of these "extrasolar planets," as they're called. Using a common-sense definition of potentially habitable planets, coupled with extensive computer simulations, scientists have calculated how many potentially habitable planets might be detected around other stars by the SIM PlanetQuest mission. ("SIM" stands for Space Interferometry Mission.)

The mission, scheduled for a launch in the next decade, will target planets with specific traits in common with Earth: a similar mass and an orbit in the "habitable zone," not too close and not too far from its parent star. With this mass and location, it's believed a planet could have liquid water on its surface and an atmosphere -- conditions considered necessary for life to gain a foothold.

The science team has shown that, in a survey of the best 120 candidate stars for hosting such planets, SIM PlanetQuest would have the sensitivity to find:

-- Planets smaller than Earth around six stars

-- Planets smaller than twice Earth’s mass around 24 stars

-- Planets smaller than about triple Earth’s mass around every star in the survey group

All planets discovered by the mission would be on a short list of targets for the futureTerrestrial Planet Finder mission, which would look for direct signatures of habitable environments and even of life itself.

The roster of six stars where SIM PlanetQuest could find Earth-like planets, if they exist, includes some familiar names, visible in the nighttime sky:

-- Sirius, in the constellation Canis Major, the closest star visible with the naked eye from the northern hemisphere's mid-latitudes, seen in winter along a line extending from Orion's belt

-- Altair, forming one corner of the "Summer Triangle"

-- Alpha Centauri, the star immortalized in the movie "Contact" and the closest bright star to Earth, visible from southernmost Texas, Florida, Hawaii and the southern hemisphere
The research is contained in a paper published September 2006 in Publications of the Astronomical Society of the Pacific. Its authors are Joseph Catanzarite and Drs. Michael Shao, Stephen Unwin, Angelle Tanner, and Jeffrey Yu, all from JPL.

More information on SIM PlanetQuest is available at: http://planetquest.jpl.nasa.gov/SIM/sim_index.cfm.

-end-

posted in Cosmology - 2 replies

Mysterious source of cosmic rays detected

2006-10-20T06:31:42Z

20:51 19 October 2006
NewScientist.com news service
David Shiga

A mysterious surplus of energetic particles called cosmic rays is striking the Earth from the direction of the constellation Cygnus, suggests a controversial new study. If confirmed, the detection of this excess may help scientists figure out what produces these enigmatic high-speed particles.

Cosmic rays are speeding charged particles that appear to hit Earth in roughly equal numbers from all directions. Lower energy cosmic rays are thought to come from the shock waves around supernovae, but the source of the higher energy ones is still a mystery.

When a cosmic ray hits Earth's atmosphere, it produces a burst of charged particles and light. Sensitive detectors on the ground measure either the secondary particles or the light to try to determine the direction from which each cosmic ray came.

However, no one has been able to unequivocally trace cosmic rays to a specific object like the expanding shell of a supernova.

Now, observations have revealed what appears to be a broad area of enhanced cosmic ray activity in the sky. The data comes from the Tibet Air Shower Arrays, which detects the secondary particles produced when cosmic rays or high-energy radiation slams into the atmosphere.

Slight excess
Researchers led by Michihiro Amenomori of Hirosaki University in Japan plotted the direction of 37 billion cosmic rays and found a slight excess of 1 part in 1000 coming from a patch of sky roughly centred on the constellation Cygnus.

This suggests there is a source of cosmic rays inside our own galaxy in this direction, says team member Yi Zhang of the Institute of High Energy Physics in Beijing, China.

The excess is in the same part of the sky that exhibits an unexplained excess of high-energy photons called gamma rays in observations by the Milgrom gamma ray detector in Los Alamos, New Mexico, US, and other instruments.

Both types of observation might be caused by one or more cosmic ray sources in the Cygnus region, Zhang says. "It would mean that those sources should not be too far from us, and this would provide us a good laboratory to study the cosmic ray acceleration," he told New Scientist.

The cosmic rays from this region could be generated in supernova shock waves, jets of matter spewing from the discs around black holes, or even decaying dark matter particles, says David Kieda of the University of Utah in Salt Lake City, US.

Broad patch
However, the result is not iron-clad. The Tibet detectors cannot distinguish between cosmic rays and gamma rays, so it might simply be seeing a gamma ray excess similar to that observed previously in this region, Kieda says.

Still, he says some of the gamma rays would probably be created by a surplus of cosmic rays hitting clumps of gas in the region. "There is obviously some kind of origin in that region, which is very exciting," he told New Scientist.

But Gus Sinnis, a member of the Milgrom gamma ray detector team, says the new observations may simply be due to a mysterious source of gamma rays detected by Milgrom and that an extra source of cosmic rays may not be involved at all.

Zhang counters that the excess seen by the Tibet detector covers a much broader patch of the sky than the previously observed gamma ray excess and so must have an additional source. "The large-scale excess towards the Cygnus region has to be attributed to charged cosmic rays," he argues.

Journal reference: Science (vol 314, p 439)

posted in Cosmology - 0 replies

Multiple Big Bang theory: Universe at least 1 trillion years old

2006-10-15T15:01:45Z

http://www.guardian.co.uk/science/story/0,,1768191,00.html

The universe is at least 986 billion years older than physicists thought and is probably much older still, according to a radical new theory.

The revolutionary study suggests that time did not begin with the big bang 14 billion years ago. This mammoth explosion which created all the matter we see around us, was just the most recent of many.

The standard big bang theory says the universe began with a massive explosion, but the new theory suggests it is a cyclic event that consists of repeating big bangs and big crunches - where every particle of matter collapses together.

"People have inferred that time began then, but there really wasn't any reason for that inference," said Neil Turok, a theoretical physicist at the University of Cambridge, "What we are proposing is very radical. It's saying there was time before the big bang."

Under his theory, published today in the journal Science with Paul Steinhardt at Princeton University in New Jersey, the universe must be at least a trillion years old with many big bangs happening before our own. With each bang, the theory predicts that matter keeps on expanding and dissipating into infinite space before another horrendous blast of radiation and matter replenishes it. "I think it is much more likely to be far older than a trillion years though," said Prof Turok. "There doesn't have to be a beginning of time. According to our theory, the universe may be infinitely old and infinitely large."

posted in Cosmology - 4 replies

The Big Bang – Common Misconceptions

2006-10-06T00:14:30Z

http://angryastronomer.blogspot.com/2006/07/big-bang-common-misconceptions.html

Recently, I’ve been hanging out on some message boards and realized that, just like with evolution, there’s a lot of really uneducated people that are being very vocal about their strawman version of the Big Bang. I began to notice that their entire argument was founded on these common misconceptions and thus, I figured it was about time to make a list of the really big ones and attempt to clear them up.

This is in no way a comprehensive list, nor is it meant to present all the evidence supporting the Big Bang, but instead, only to hit the highlights.

He talks about these 4 misconceptions:

1) The Big Bang was not an explosion
2) The Big Bang theory doesn’t explain what caused it
3) There’s no evidence for the Big Bang
4) The Big Bang doesn’t leave room for God

posted in Cosmology - 7 replies

Donut feast may explain giant stars

2006-10-05T07:05:36Z

"Donut feast may explain giant stars"
27 September 2006
From New Scientist Print Edition.
Original Link: http://www.newscientistspace.com/article.ns?id=mg19125715.100&feedId=online-news_rss20

Tools

Stars may grow to extreme masses by accumulating dust from a donut-like disc around them (Illustration: Bill Saxton/NRAO/AUI/NSF) A long-standing mystery over how massive stars are born could be cleared up thanks to the first observation of the birth of such a sun.

Astronomers know low-mass stars like our sun form by gathering material from gas clouds like those in the Eagle nebula (above). But that can't explain how stars bigger than about 10 times the mass of the sun could form without their intense radiation blasting away surrounding material before they reach full size.

One solution is that big stars form from doughnut-shaped gas clouds in which stellar radiation escapes in beams along the stars' poles. An alternative suggestion is that they could form when mid-sized stars collide, but until now there was no observational evidence either way.

Now Maria Beltrán at the University of Barcelona in Spain and her colleagues have observed the birth of a large star in a rotating doughnut-shaped cloud, with matter falling into a young star core and an outflow of stellar radiation from the poles (Nature, vol 443, p 427).

"Nobody had seen all three of these features at the same time," says Beltrán. This clearly supports the gas cloud theory of how high-mass stars form, she says. "But the collision theory may still be true for star formation in other places," she adds.

From issue 2571 of New Scientist magazine, 27 September 2006, page 21

posted in Cosmology - 8 replies

Mysterious quasar casts doubt on black holes

2006-07-29T00:25:04Z

http://www.newscientistspace.com/article/dn9620-mysterious-quasar-casts-doubt-on-black-holes.html

Mysterious quasar casts doubt on black holes

A controversial alternative to black hole theory has been bolstered by observations of an object in the distant universe, researchers say. If their interpretation is correct, it might mean black holes do not exist and are in fact bizarre and compact balls of plasma called MECOs.

Rudolph Schild of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, led a team that observed a quasar situated 9 billion light years from Earth. A quasar is a very bright, compact object, whose radiation is usually thought to be generated by a giant black hole devouring its surrounding matter.

A rare cosmological coincidence allowed Schild and his colleagues to probe the structure of the quasar in much finer detail than is normally possible. Those details suggest that the central object is not a black hole. "The structure of the quasar is not at all what had been theorised," Schild told New Scientist.

A black hole, as traditionally understood, is an object with such a powerful gravitational field that even light is not fast enough to escape it. Anything that gets within a certain distance of the black hole's centre, called the event horizon, will be trapped.

A well accepted property of black holes is that they cannot sustain a magnetic field of their own. But observations of quasar Q0957+561 indicate that the object powering it does have a magnetic field, Schild's team says. For this reason, they believe that rather than a black hole, this quasar contains something called a magnetospheric eternally collapsing object (MECO). If so, it would be best evidence yet for such an object.
Flickering clues

The researchers used gravitational lensing to make their close observation of the quasar. This technique exploits rare coincidences that can occur when a galaxy sits directly between a distant object and observers on Earth.

The gravity of the intervening galaxy acts like a lens. As the intervening galaxy's individual stars pass in front of the quasar, this bending varies, making the quasar appear to flicker.

Carefully scrutinising this flickering allowed the researchers to probe fine details of the quasar's structure that are normally far too small to be resolved by even the most powerful telescopes.
Magnetic sweep

The researchers found that the disc of material surrounding the central object has a hole in it with a width of about 4000 Astronomical Units (1 AU is the distance between the Earth and the Sun). This gap suggests that material has been swept out by magnetic forces from the central object, the researchers say, and must therefore be a MECO, not a black hole.

"I believe this is the first evidence that the whole black hole paradigm is incorrect," says Darryl Leiter of the Marwood Astrophysics Research Center in Charottesville, Virginia, US, who co-authored the study. He says that where astronomers think they see black holes, they are actually looking at MECOs.

According to the MECO theory, objects in our universe can never actually collapse to form black holes. When an object gets very dense and hot, subatomic particles start popping in and out of existence inside it in huge numbers, producing copious amounts of radiation. Outward pressure from this radiation halts the collapse so the object remains a hot ball of plasma rather than becoming a black hole.
Extremely complex

But Chris Reynolds of the University of Maryland, in College Park, US, says the evidence for a MECO inside this quasar is not convincing. The apparent hole in the disc could be filled with very hot, tenuous gas, which would not radiate much and would be hard to see, he says. "Especially if you're looking with an optical telescope, which is how these observations were made, you wouldn't see that gas at all," he told New Scientist.

Leiter says this scenario would leave other things unexplained, however. The observations show that a small ring at the inner edge of the disc is glowing, which is a sign that it has been heated by a strong magnetic field, he says. In Reynolds's scenario, one would expect a much broader section of the disc to be heated, he says.

In any case, says Reynolds, it is difficult to draw conclusions from the team's detailed comparisons of their observations with models of black holes because those models are far from definitive. "We know the accretion of gas into black holes is an extremely complex phenomenon," he says. "We don’t know precisely what that would look like."

"It would be truly exciting if there was compelling evidence found for a non-black-hole object in these quasars," Reynolds adds. "I just don't think that this fits."

Journal reference: The Astronomical Journal (vol 132, p 420)

posted in Cosmology - 1 reply

How dead stars make planets

2006-07-20T23:28:48Z

How dead stars make planets

http://www.usatoday.com/tech/science/space/2006-04-05-planet-birth_x.htm

Rings of debris formed in the aftermath of stellar explosions could fuel the birth of new, rocky planets around dead stars. They could also provide an alternative way to make black holes, scientists said Wednesday.

Using NASA's Spitzer Space Telescope, researchers detected a cool disk of material glowing in infrared light around a young X-ray pulsar, a type of neutron star that sends out regular, directed pulses of radiation like a lighthouse beam. A neutron star is a dead star that has lost most of its material in an explosion.

An animation shows how the process might work.

posted in Cosmology - 8 replies

Big Bang Paradox

2006-07-20T18:35:06Z

If we had an optical device that was powerful enogh, could we look out into the cosmos and see the Big Bang? Since our best estimates of the age of the Universe are about 15 Billion years, then it follows that if we could see light from 15 Billion light years out, then that light would be from the "flash" of the Big Bang. Is my reasoning correct here?
If so, then to see the Singularity that started it All, then we would need to look to the extreme of bigness. I have trouble with this, to see the tiny point we need to look as far as we can?!?

Any help with this would be apreciated.

Skott

posted in Cosmology - 24 replies

The Gravitas of Gravity...

2006-07-12T00:26:41Z

From Space.com:

http://www.space.com/scienceastronomy/060711_science_tuesday.html

By Michael Schirber
Special to SPACE.com
posted: 11 July 2006
06:05 am ET

Public confidence in the "constants" of nature may be at an all time low. Recent research has found evidence that the value of certain fundamental parameters, such as the speed of light or the invisible glue that holds nuclei together, may have been different in the past.

"There is absolutely no reason these constants should be constant," says astronomer Michael Murphy of the University of Cambridge. "These are famous numbers in physics, but we have no real reason for why they are what they are."

The observed differences are small—roughly a few parts in a million—but the implications are huge: The laws of physics would have to be rewritten, not to mention we might need to make room for six more spatial dimensions than the three that we are used to.

Lines of evidence

The evidence for varying constants focuses primarily on quasar studies.

Quasars are extremely luminous objects, powered by giant black holes. Some of them are so far away that their light was emitted 12 billion years ago.

The Other Side
Not all quasar data is consistent with variations. In 2004, a group of astronomers—including Patrick Petitjean of the Astrophysical Institute of Paris—found no change in the fine structure constant using quasar spectra from the Very Large Telescope in Chile. No one has yet explained the discrepancy with the Keck telescope results.

"These measurements are so difficult and at the extreme end of what can be achieved by the telescopes that it is very difficult to answer this question," Petitjean says.

Other experiments outside astronomy have found no evidence for variation in the fine structure constant (alpha), although they do not probe the same time period as the quasars.

Atomic clocks: By comparing extremely accurate clocks, researchers have shown that the current change per year in alpha is less than one part in a million billion.
Oklo mine: This uranium mine in Africa was the site of a naturally-occurring nuclear reactor two billion years ago. An early study concluded that alpha has not changed more than 10 parts in a billion since the reactor ran. But a more recent analysis shows that this depends on certain assumptions.
Anthropic arguments: For life to have arisen on Earth, many constants could not have been very different from what they are. For instance, if alpha changed by 4 percent, then carbon could not be made in stars.

Astronomers study the spectra of this ancient light to determine if the early universe was different than now. Specifically, they look at absorption lines, which are due to gas clouds between us and the quasars.

The lines reveal exactly what is in the clouds, since each type of atom has a "fingerprint"—a set of specific frequencies at which it absorbs.

In 1999, Murphy and his colleagues found the first convincing evidence that these fingerprints change with time. Using data from the Keck observatory in Hawaii, they detected a frequency difference between billion-year-old quasar lines and the corresponding lines measured on Earth.

Some of these Earth-bound lines were not well characterized, so Murphy and others recently performed careful lab experiments to confirm that there is indeed a shift in the quasar spectra. A spectra is basically light split into its component frequencies, much like when white light goes through a prism to produce a rainbow.

What's in a constant

Because the frequencies of absorption lines depend on various parameters, the quasar observations are sometimes interpreted as indicating that light was faster in the past, or that the electron had a weaker charge.

But theorist Carlos Martins of the University of Cambridge tells LiveScience that this is not entirely correct: "It doesn't make sense to talk about a varying speed of light or electron charge."

This is because the values of these parameters include units that might change. The speed of light, for instance, might be measured one day with a ruler and a clock. If the next day the same measurement gave a different answer, no one could tell if the speed of light changed, the ruler length changed, or the clock ticking changed.

To avoid this confusion, scientists use dimensionless constants—pure numbers that are ratios of measured quantities.

In the case of the shifts in Murphy's data, the relevant dimensionless constant is the fine structure constant (often designated by the Greek letter alpha), which characterizes the strength of the electromagnetic force.

The researchers found that alpha was smaller in the past, but other "famous numbers" would not be immune to the vagaries of time.

"You would expect variation in all the fundamental constants," Murphy says.

It was therefore not entirely a surprise when—in April of this year—Patrick Petitjean of the Astrophysical Institute of Paris and his collaborators detected a change in the proton to electron mass ratio from molecular absorption lines in quasar spectra.

The four fundamental forces can each be characterized by a dimensionless constant.

Strong: Glues together the parts of a nucleus.

Electromagnetic: Holds electrons around atoms; explains light.

Weak: Responsible for certain radioactive decays.

Gravity: Keeps planets, stars, glaxies from flying apart.

The mass variation can be interpreted as the strong force's coupling constant being larger in the early universe, Petitjean says.

A hole in the theory

Time-varying constants of nature violate Einstein's equivalence principle, which says that any experiment testing nuclear or electromagnetic forces should give the same result no matter where or when it is performed.

If this principle is broken, then two objects dropped in a gravitational field should fall at slightly different rates. Moreover, Einstein's gravitational theory—general relativity—would no longer be completely correct, Martins says.

A popular alternative to relativity, which assumes that sub-atomic particles are vibrating strings and that the universe has 10 or more spatial dimensions, actually predicts inconstant constants.

According to this string theory, the extra dimensions are hidden from us, but the "true" constants of nature are defined on all dimensions. Therefore, if the hidden dimensions expand or contract, we will notice this as a variation in our "local" 3D constants.

Even if string theory is not correct, the current model of gravity will likely need to be revised to unite it with the other three fundamental forces.

"We have an incomplete theory, so you look for holes that will point to a new theory," Murphy says. Varying constants may be just such a hole.

posted in Cosmology - 1 reply

"top-down" cosmology

2006-05-07T03:33:50Z

http://www.brothersjudd.com/blog/archives/2006/04/oughtnt_we_dig.html

Hawking and Hartle's original work on the quantum properties of the cosmos suggested that imaginary time, which seemed like a mathematical curiosity in the sum-over-histories approach, held the answer to understanding the origin of the universe.

Add up the histories of the universe in imaginary time, and time is transformed into space. The result is that, when the universe was small enough to be governed by quantum mechanics, it had four spatial dimensions and no dimension of time: where time would usually come to an end at a singularity, a new dimension of space appears, and, poof! The singularity vanishes.

In terms of the universe's history, that means there is no point A. Like the surface of a sphere, the universe is finite but has no definable starting point, or "boundary". Hence the idea's name: the no-boundary proposal.

This has led Hawking to define a new kind of cosmology. The traditional approach, which Hawking calls "bottom-up" cosmology, tries to specify the initial state of the universe and work from there. This is doomed to fail, Hawking says, because we know nothing about the starting conditions. Instead, he suggests, we should use the no-boundary proposal to do "top-down" cosmology, where the only input into our models of the universe comes from what we observe now - together with the idea that our universe has no boundary in the past.

Improbable tuning

The result of this process, he says, solves a long-standing problem of cosmology: fine-tuning. Most cosmologists think, for example, that the universe went through an early burst of rapid expansion, or "inflation". There is some evidence to support the claim, but there's also a problem. Standard inflationary models require a very improbable initial state, one that must have "finely tuned" values that cause inflation to start, then stop in a certain way after a certain time: a complicated prescription whose only justification is to produce a flat universe without any strange topology, and so on - a universe like ours.

posted in Cosmology - 0 replies

The Void's Incredible Richness

2006-04-14T07:13:50Z

The Void's Incredible Richness

The image covers an 'empty' region of the sky five times the size of the full moon, opening an exceptionally clear view towards the most distant part of our universe. It reveals objects that are 100 million times fainter than what the unaided eye can see.

http://www.eso.org/outreach/press-rel/pr-2006/pr-14-06.html

---

Amazing that there are hundreds of not thousands of galaxies present where we need nothing but a small section of blackness in our night sky. And each galaxy can have 100 billion stars or more with who knows how many planets in orbit.

posted in Cosmology - 0 replies

Interesting binary star system observed

2006-04-11T00:08:54Z

http://www.spacedaily.com/reports/Exploding_Star_Within_A_Star_Surprises_Astronomers.html

Last Feb. 12, amateur astronomers around the world began reporting something that teams of their professional counterparts had been eagerly awaiting: A faint star in the constellation Ophiuchus suddenly became clearly visible to the naked eye in the night sky. With that news, an international team trained dozens of instruments both ground-based and orbiting on RS Ophiuchi, a star known to have exhibited five such brightenings over the past 108 years.

posted in Cosmology - 0 replies

Big Bang News: Early Universe's Rapid Expansion Confirmed

2006-04-04T23:07:54Z

http://www.wired.com/news/wireservice/0,70425-0.html?tw=rss.index

Physicists announced Thursday that they now have the smoking gun that shows the universe went through extremely rapid expansion in the moments after the big bang, growing from the size of a marble to a volume larger than all of observable space in less than a trillion-trillionth of a second.

The discovery -- which involves an analysis of variations in the brightness of microwave radiation -- is the first direct evidence to support the two-decade-old theory that the universe went through what is called inflation.

It also helps explain how matter eventually clumped together into planets, stars and galaxies in a universe that began as a remarkably smooth, super-hot soup.

"It's giving us our first clues about how inflation took place," said Michael Turner, assistant director for mathematics and physical sciences at the National Science Foundation. "This is absolutely amazing."

Brian Greene, a Columbia University physicist, said: "The observations are spectacular and the conclusions are stunning."

posted in Cosmology - 5 replies

Probe returns first Mars pictures

2006-03-26T02:02:09Z

Probe returns first Mars pictures

http://news.bbc.co.uk/2/hi/science/nature/4844850.stm

Nasa is studying the first pictures taken of the surface of the Red Planet by the high-resolution cameras aboard the Mars Reconnaissance Orbiter (MRO).

posted in Cosmology - 0 replies

Multiverse: a universe of universes

2006-03-22T06:19:11Z

http://en.wikipedia.org/wiki/Multiverse

Fun reading.

posted in Cosmology - 0 replies

Brown dwarf stars: the little stars that couldn't

2006-03-15T19:55:29Z

Brown dwarfs are stars that, because they lack sufficient mass, fail to achieve nuclear fusion.

http://www.physorg.com/news11800.html

Astronomers, at last, get a chance to size up a brown dwarf

Brown dwarfs -- failed stars that fall somewhere between the smallest stars and the largest planets on the spectrum of heavenly objects -- have always been viewed by astronomers as a critical link in the understanding of how both stars and planets form.

posted in Cosmology - 0 replies

Solar storm facts

2006-03-12T07:18:19Z

It's official: Solar minimum has arrived. Sunspots have all but vanished. Solar flares are nonexistent. The sun is utterly quiet.

Like the quiet before a storm.

This week researchers announced that a storm is coming--the most intense solar maximum in fifty years. The prediction comes from a team led by Mausumi Dikpati of the National Center for Atmospheric Research (NCAR). "The next sunspot cycle will be 30% to 50% stronger than the previous one," she says. If correct, the years ahead could produce a burst of solar activity second only to the historic Solar Max of 1958.

http://science.nasa.gov/headlines/y2006/10mar_stormwarning.htm?list134784

posted in Cosmology - 0 replies

Neutrino oscillation

2006-02-24T16:35:10Z

I recommend this week's PBS Nova program. It talks about a recently solved problem with neutrinos. The answer to the problem upset the Standard Model that says that neutrinos travel at the speed of light and do not have mass. You might be able to catch a rebroadcast if you check your listings.

http://www.pbs.org/wgbh/nova/neutrino/

The solar neutrino problem is considered solved:
http://en.wikipedia.org/wiki/Solar_neutrino_problem

---

This was a neat problem for me to see solved because this was talked about in my astrophysics class as a real problem with astrophysics and particle physics.

posted in Cosmology - 1 reply

Rare gamma-ray flare from a distant star disturbs Earth's daytime ionosphere

2006-02-20T17:52:48Z

http://www.eurekalert.org/pub_releases/2006-02/su-rgf021706.php

On Dec. 27, 2004, scientists detected the largest gamma-ray burst ever recorded. It came from a magnetar--a neutron star with an enormous magnetic field--50,000 light years away. Its powerful rays penetrated deep into the ionosphere, the electrically conductive layer encircling Earth. On Feb. 19 in St. Louis at the annual meeting of the American Association for the Advancement of Science (AAAS), Stanford electrical engineering Professor Umran Inan will describe what scientists learned from this rare and dramatic atmospheric disturbance.

"Enormous gamma-ray flares--such as this giant flare from magnetar SGR 1806-20--affect our lower ionosphere to such a massive degree that by simply watching and measuring its response to and recovery from the flare, we are bound to learn more about the dynamics of these upper atmospheric regions, which are ultimately so important for our quantitative understanding of space weather, as well as communication and navigation systems," said Inan in a recent interview. With more than 250 technical publications, he is a pioneer in the discovery of atmospheric electrical phenomena known as "elves" (horizontally expanding discharges at high altitudes), "red sprites" (diffuse blobs that begin at the base of the ionosphere) and "blue jets" (branches that shoot up from cloud tops).

His talk is part of a symposium, "A Giant Flare from a Magnetar: Blitzing the Earth from Across the Galaxy," that includes astrophysicists Kevin Hurley of the University of California-Berkeley, David Palmer of Los Alamos National Laboratory, Bryan Gaensler of the Harvard-Smithsonian Center for Astrophysics and Lynn Cominsky of Sonoma State University.

For the astrophysicists, the colossal flare is a window into the workings of a neutron star. They observed the gamma-ray flare using two orbiting spacecrafts and will use new knowledge about the event to hone their theories about these distant objects.

posted in Cosmology - 0 replies

Black Hole FAQ

2006-02-03T18:27:15Z

http://cosmology.berkeley.edu/Education/BHfaq.html

* What is a black hole?
* How big is a black hole?
* What would happen to me if I fell into a black hole?
* My friend Penelope is sitting still at a safe distance, watching me fall into the black hole. What does she see?
* If a black hole existed, would it suck up all the matter in the Universe?
* What if the Sun became a black hole?
* Is there any evidence that black holes exist?
* How do black holes evaporate?
* Won't the black hole have evaporated out from under me before I reach it?
* What is a white hole?
* What is a wormhole?
* Where can I go to learn more about black holes?

posted in Cosmology - 0 replies

Gravity theory dispenses with dark matter

2006-01-25T20:44:38Z

http://www.newscientistspace.com/article/dn8631-gravity-theory-dispenses-with-dark-matter.html

A modified theory of gravity that incorporates quantum effects can explain a trio of puzzling astronomical observations – including the wayward motion of the Pioneer spacecraft in our solar system, new studies claim.

The work appears to rule out the need to invoke dark matter or another alternative gravity theory called MOND (Modified Newtonian Dynamics). But other experts caution it has yet to pass the most crucial test – how to account for the afterglow of the big bang.

Astronomers realised in the 1970s that the gravity of visible matter alone was not enough to prevent the fast-moving stars and gas in spiral galaxies from flying out into space. They attributed the extra pull to a mysterious substance called dark matter, which is now thought to outweigh normal matter in the universe by 6 to 1.

But researchers still do not know what dark matter actually is, and some have come up with new theories of gravity to explain the galaxy observations. MOND, for example, holds that there are two forms of gravity.

Above a certain acceleration, called a0, objects move according to the conventional form of gravity, whose effects weaken as two bodies move further apart in proportion to the square of distance. But below a0, objects are controlled by another type of gravity that fades more slowly, decreasing linearly with distance.

But critics point out that MOND cannot explain the observed masses of clusters of galaxies without invoking dark matter, in the form of almost massless, known particles called neutrinos.
Quantum fluctuations

Now, Joel Brownstein and John Moffat, researchers at the Perimeter Institute for Theoretical Physics and the University of Waterloo in Ontario, Canada, say another modified gravity theory can account for both galaxies and galaxy clusters.

The theory, called scalar-tensor-vector gravity (STVG), adds quantum effects to Einstein's theory of general relativity. As in other branches of physics, the theory says that quantum fluctuations can affect the force felt between interacting objects.

In this case, a hypothetical particle called a graviton – which mediates gravity – appears in large numbers out of the vacuum of space in regions crowded with massive objects such as stars. "It's as if gravity is stronger" near the centres of galaxies, Brownstein told New Scientist. "Then, at a certain distance, the stars become sparse, and the gravitons don't contribute that much." So at larger distances, gravity returns to the behaviour described by Newton.
Pioneer 10 anomaly

Brownstein and Moffat tested the theory in several ways. They estimated that their gravitational change occurs 46,000 light years out from the centre of a large galaxy and half that distance for a small galaxy. They applied these estimates to 101 observed galaxies, and found that both their theory and MOND could account for their rotations. "The point is that neither of the two theories had any dark matter in them," says Brownstein.

But the theories did diverge when the pair tested them against observations of 106 galaxy clusters. MOND could not reproduce the observed cluster masses but STVG accounted for more than half.

Furthermore, the team tested the theory against observations of NASA's 34-year-old Pioneer 10 spacecraft, which appears about 400,000 kilometres away from its expected location in the outer solar system. Brownstein says the theory fits observations of the so-called Pioneer anomaly (see New Scientist feature, 13 things that do not make sense), while MOND cannot address it because Pioneer's acceleration is above a0.
Big bang's afterglow

"At three different distance scales, we see answers that agree with experiment," says Brownstein. "They are claiming they can solve all the world's problems," agrees Sean Carroll, a cosmologist at the University of Chicago in Illinois, US. But these experiments are "not what most cosmologists would first think of if they were going to test a new theory of gravity".

He says any theory must also explain the development of large-scale structures in the universe, and most importantly, the afterglow of the big bang. Called the cosmic microwave background (CMB) radiation, this afterglow was produced about 370,000 years after the big bang when the first atoms formed and has been studied in great detail by satellites, such as NASA's WMAP probe.

"The dark matter model is not perfect, but it made a very specific prediction for the microwave background that seems to be coming true, and it fits galaxies and clusters and large-scale structure and gravitational lensing," Carroll told New Scientist. "Nobody would be happier than me if it turned out to be modified gravity rather than dark matter, but it's becoming harder and harder to go along with that possibility."

Brownstein says the team is currently testing its theories with work on CMB studies.

posted in Cosmology - 0 replies

milky way warp

2006-01-24T01:23:34Z

I heard a report on the radio about the three ways the milky way vibrates.

http://www.astronomy.com/asy/default.aspx?c=a&id=3834

i think this article explains it.

posted in Cosmology - 1 reply

Space telescopes capture a cosmic jellyfish shaped galaxy

2006-01-16T21:03:34Z

http://www.newscientistspace.com/article.ns?id=dn8582

A cosmic jellyfish appears to pulse with light in this multi-wavelength image of the Cartwheel galaxy, compiled from images taken by four space telescopes.

The galaxy probably came by its distinctive shape when a small galaxy – possibly one of the objects at bottom-left of the image – collided with it head-on 100 million years ago. The crash set off ripples in the large galaxy's gas that led to concentric rings of star birth.

posted in Cosmology - 0 replies

Scientists Find Black Hole's 'Point of No Return'

2006-01-10T00:53:52Z

By a score of 135 to zero, scientists using NASA's Rossi X-ray Timing Explorer have compared suspected neutron stars and black holes and found that the black holes behaved as if each one has an event horizon, the theoretical border from beyond which nothing, not even light, can escape.

[more]

http://www.physorg.com/news9693.html

posted in Cosmology - 0 replies

Amateur Stargazers Wanted :

2005-12-20T13:24:54Z

To Help Solve Supernova Mystery

Columbus OH (SPX) Dec 19, 2005
Ohio State University scientists have thought of a new way to solve an astronomical mystery, and their plan relies on a well-connected network of amateur stargazers and one very elusive subatomic particle.
To understand what happens inside exploding stars, or supernovae, scientists need to study particles called neutrinos, explained John Beacom, assistant professor of physics and astronomy at Ohio State. Neutrinos are formed in the nuclear reactions that make stars like our sun shine. Exploding stars overflow with the particles, and flood the universe with them.

Neutrinos should be everywhere, but they are very hard to detect - so hard to detect, in fact, that even though countless neutrinos burrow through our planet every second, scientists only capture a few of them each day.

Scientists know that most neutrinos they do detect probably come from our own sun, from nuclear reactors in terrestrial power plants, or from cosmic radiation interacting with our atmosphere. There has been no way to distinguish whether a particular neutrino came from elsewhere, until now.

That's why Beacom and his team's discovery - that each year, one or two of the neutrinos detected on Earth can probably be matched to the exploding star that made them - represents a major step forward for supernova astrophysics.

The discovery also comes at a special time, Beacom said. The method will fully exploit the capabilities of the next generation of neutrino detectors, which are now being planned, and take advantage of a growing number of amateur astronomers who are capable of discovering supernovae.

For a study appearing in a recent issue of the journal Physical Review Letters, Beacom and his coauthors developed a kind of litmus test for finding supernova neutrinos: If a detector on Earth registers two of the particles within ten seconds, odds are high that they came from a supernova in a nearby galaxy. Alternatively, if an astronomer - amateur or otherwise - spots a supernova, scientists at neutrino detectors can look back through their records to see if they captured a neutrino around that time.

Given that a few supernovae occur in nearby galaxies every year, and given the sensitivity of neutrino detectors on Earth, they've determined that at least one of those scenarios - the two-in-ten-seconds event or the identification of a supernova neutrino after the fact - should be able to happen about once a year.

The professionals need amateur astronomers to help spot new supernovae fast, so scientists can quickly match captured neutrinos with the exploding stars that made them.

"Even with all our modern telescopes, the professionals can't look at the whole sky at once," Beacom said. "But the amateurs are everywhere. With relatively small telescopes, they can see these nearby supernovae, which are very bright - often brighter than their host galaxies."

Here, "relatively small" means smaller than a telescope in an astronomical observatory, but larger than the average backyard telescope.

Coauthor Hasan Yüksel, a postdoctoral researcher at Ohio State, explained that many of today's so-called amateur astronomers aren't really so amateur. "You can think of them more as 'professional amateurs,'" he said.

These are the semi-pro players of the hobby set - skilled folks who build custom telescopes. They have day jobs, but they scan the skies at night, and share their findings with other amateurs over the Internet. Often, they have ties to professional astronomers. When a major discovery is made, they know as soon as the professionals do.

Yüksel also pointed out that since 2002, there were at least nine supernovae identified in galaxies within about 30 million light years (180 trillion miles) of our Milky Way, and more than half of those were discovered by amateurs.

Surprisingly, the Ohio State physicists got their idea in a "eureka" moment -- after a discussion with colleagues at the Department of Astronomy's morning coffee event. This daily review of new journal papers posted to an online archive (http://arXiv.org) has been going on since the 1990s, and often inspires faculty and students to pursue new lines of research.

Walking back to their offices after coffee, Yüksel asked Beacom and visiting scholar Shin'ichiro Ando about a special class of galaxies called starburst galaxies, in which unusually high numbers of stars are being born. Wouldn't those galaxies also have large numbers of supernovae? Wouldn't nearby starburst galaxies be good places to look and find out?

Beacom said that something clicked.

"We realized that maybe it's not totally crazy to look for neutrinos from supernovae in nearby galaxies," he said.

The three performed detailed calculations about supernova rates in nearby galaxies, and found that the explosions probably happen more often than people once thought - about three times a year. Then they looked at the rates at which neutrinos are caught in giant underground detectors on Earth.

Their discovery came down to calculating the odds: it's highly unlikely that a neutrino detector on Earth would capture two particles within any 10 second interval unless both of those neutrinos came from a supernova - in fact, the same supernova.

"We were kicking ourselves for not thinking of this before," Beacom said.

He cited Supernova 1987A, which occurred in a galaxy that is a very close companion to the Milky Way. Because detectors on Earth captured 20 neutrinos in only a few seconds during that event, astronomers knew for sure that they came from 1987A.

But since then?

"A big fat zero," he said. "What if using this technique, we could have been identifying one additional supernova neutrino per year? By now, we would have collected a sample as big as that burst in 1987." With the much larger neutrino detectors that are now being devised, and with the large number of supernovae that are being spotted these days, it could be done.

Galaxies up to 200 times farther away than the one that spawned Supernova 1987A are still considered near by astronomical standards, and amateurs would be able to spot supernovae in them. Those galaxies may give us only one or two neutrinos per year, but that's still more than scientists would be able to study otherwise.

"These are somewhat desperate measures," Ando admitted. "Why are we so desperate? Since a supernova expends 99 percent of its energy in neutrinos, those neutrinos tell the story of how the explosion works, and therefore we have to find them." Supernova neutrinos are everywhere, but the vastness of space keeps them hidden.

So, at least a thousand years after people first noticed supernovae in the skies, what's happening inside these exploding stars is still a mystery. When scientists simulate supernovae on computer, something always goes wrong. The explosion starts, and then it fizzles.

"If we can't make a supernova blow up on the computer, that means we're missing something. We need clues. We need to find those neutrinos," Ando continued.

Beacom envisions that scientists at neutrino detectors could sound an alarm whenever they detect two particles in ten seconds. Since supernovae emit neutrinos at the very start of the explosion, the particles would reach Earth hours before the supernovae would be visible in telescopes, and the announcement would amount to a supernova forecast.

Alternatively, when astronomers spot a nearby supernova, they could ask the scientists at the detectors to look back through their data from previous hours to find any particle events.

At Beacom's suggestion, scientists working at the Japanese neutrino detector Super-Kamiokande are going to search their records for events that could be linked to nearby supernovae in past years.

"While this detector is smaller than those envisioned for the future, it's been in operation for a decade or two, so it actually stands a good chance of having detected the first neutrino from an identified supernova beyond the Milky Way and its closest companions," Beacom said.

Related Links
http://www.osu.edu/
http://www.spacedaily.com/news/supernova-05i.html

posted in Cosmology - 0 replies

Stars created due to gravitational interactions between galaxies

2005-12-04T08:30:06Z

http://www.newscientistspace.com/article.ns?id=dn8277

Hundreds of new stars are igniting in the wake of intense gravitational interactions between four galaxies, new observations reveal.

The four galaxies – called Robert's Quartet – lie about 160 million light years from Earth in the southern constellation Phoenix. They are crowded into a space just 150,000 light years across – only 1.5 times the width of our galaxy, the Milky Way.

That proximity makes them one of the best known examples of a compact group of galaxies, whose members gravitationally disturb each other. In the group's largest galaxy, NGC 92 (left), that interaction has sparked the creation of about 200 star-forming regions and unravelled a stream of gas and dust stretching 100,000 light years.

Nearly 60 stellar nurseries have sprung up in the irregular galaxy NGC 87, in the upper right of the image, while a ring of enhanced star birth circles the spiral galaxy NGC 89 (lower middle). The observations were made with the FORS2 spectrograph on the European Southern Observatory's Very Large Telescope in Chile.

posted in Cosmology - 1 reply

Universe Merely Appears to Have Three Spatial Dimensions

2005-12-04T08:25:00Z

Well, according to these scientists:
---

http://www.dailycal.org/article.php?id=20361

In quantum physics, nothing is as it seems. As physicists continue to study the universe they continually run into new questions that shake how humans understand the universe's intricate mechanics.

UC Berkeley physics professor, Raphael Bousso, is trying to break down the mysteries of the universe with a concept called the holographic principle. Physicists stumbled on the idea while studying black holes. It is a concept, which ultimately questions whether the third dimension exists.

"There's a real conflict between the way that we're thinking about the world right now, which is a very local way where everything happens independently in different regions of space and the way that we're going to have to think about it," said Bousso in an interview.

Bousso presented the ideas at a seminar last weekend called "Latest Theories About the Universe and Its Governing Laws: Theoretical Physics Made Easy for the Public" at the Lawrence Hall of Science to an audience of about 100.

The holographic principle uses the optical concept of holograms to try to visually explain the complex idea. Holograms are most often used on credit cards and are images that look three dimensional, but they exist on a two dimensional surface.

"You have to keep in mind that we're just using that name as a sort of metaphor for something that we're specifying quite precisely when we're talking about how much information there is relative to certain areas," he said.

A computer chip is a good way to visualize the principle. The chip has information stored on it in the form of data, but this isn't the information Bousso is talking about. Information in the holographic principle means the entire collection of matter the chip is made of.

"One way of quantifying the complexity of matter is to ask how many different states can it be in? How many things can you wiggle in? How many different ways?" Bousso said.

It would seem logical that if you doubled the size of the chip, then you could store twice as much information on the chip.

"What we've found is that it appears that gravity conspires against that when you really try to store a lot of information in a special region, then once you double that region you can't store twice as much anymore," Bousso said.

In other words, if you have a bunch of grapes in the fridge and have all the information including water content, temperature and anything else, you should be able to create an exact replica of the grapes.

Physicists have found the information content doesn't hinge on volume, but rather on surface area. An information increase can only happen on a two-dimensional surface and information density cannot increase by volume, a three-dimensional measurement.

"The total amount of information that you can store in the world grows only like the surface area of the region that you're considering," he said.

The discovery ultimately says the concept shows the third dimension could be an illusion because complex calculations can't prove it exists. The recognition is a step of progress, but Bousso doesn't know where it will ultimately lead.

"It may be a major step, it may just be one piece in a very big puzzle, but I think it's definitely progress towards that goal," he said.

Although there is practical way to use these principles right now, Bousso said he and fellow physicists are driven to understand nature at the most fundamental level.

Albert Einstein didn't have any practical applications for his theory of relativity when he first discovered it, but now the concept is woven into today's technology with things like global positioning systems, he said.

"It happens to be true that sooner or later these types of progress have not just had practical applications, but they really underlie almost everything that we can do technologically today," Bousso said.

Ultimately, the physicist wants to find the origins and the implications of the holographic principle.

He said the principle has given insight into physics concepts that scientists have understood for years.

"It gives us a preview of some of the unifications and the explanatory power that the quantum gravity we're seeking is going to have," Bousso said.

posted in Cosmology - 4 replies

The Prehistoric Alignment of World Wonders

2005-12-02T00:33:50Z

Blow your mind:
http://home.hiwaay.net/~jalison/index.html

Exerpts:
--"Great circles are straight lines that go all the way around the center of the earth. The equator is a great circle. Meridians of longitude that cross over the north and south poles are also great circles."

--"Easter Island, Nazca, Ollantaytambo, Paratoari, Tassili n'Ajjer and Giza are all aligned on a single great circle. Additional ancient sites that are located within one tenth of one degree of this great circle include Petra; Perseopolis; Khajuraho; Pyay, Sukothai and Anatom Island."

--"The relationship between the distances from Angkor Vihear to the Great Pyramid and from the Great Pyramid to the Nazcan Hummingbird is also a precise expression of φ:

4,754 x 1.618 = 7,692

Because the Hummingbird and Angkor Vihear are antipodal sites, with a distance between them of one-half of the circumference of the earth, two Golden Section relationships between these three sites are shown by the circumference of the earth along the line of ancient sites."

--"Percentage of circumference:__First three digits of Fibonacci numbers:
Angkor to Giza: 19.1%________#137: 191... (Prime)
Giza to Nazca: 30.9%_________#138: 309...
Nazca to Angkor: 50.0%_______#139: 500...

Distance between sites:_______First five digits of Fibonacci numbers:
Angkor to Giza: 4,754 miles____#359: 47542... (Prime)
Giza to Nazca: 7,692 miles_____#360: 76924...
Nazca to Angkor: 12,446 miles__#361: 12446..."

--"Easter Island is triangular and the three volcanic peaks on Easter form an isosceles triangle with an apex angle of 108° and base angles of 36°. The ratio between the length of the base and the lengths of the sides is φ (6.8 miles x 1.618 = 11 miles)."

--"The straight line distance, through the Earth, from Angkor Wat to Easter (7,574 miles), plus the straight line distance from Easter to Macchupicchu (2,522 miles), equals the great circle distance from Angkor Wat to Easter (10,096 miles).

The straight line distance from the Great Pyramid to Easter (7,566 miles) is three times the straight line distance from Easter to Machupicchu (2,522 miles).

The straight line distance from Easter to its antipodal point in the Indus Valley (7,924 miles), which is also the diameter of the Earth, is 3.1416 times the straight line distance from Easter to Machupicchu (2,522 miles), a precise expression of π.

Since the circumference of the Earth is also 3.1416 times the diameter of the Earth, the straight line distance from Easter to Machupicchu times π² equals the circumference of the Earth."

--"As the Earth rotates on it’s axis, the Equator remains aligned, but the line of ancient sites describes a sine wave as a result of it’s tilt relative to the Equator. The line of the ecliptic may be observed describing a similar wave by spinning a globe that has a line of the ecliptic.

The wavelength is equal to the circumference of the Earth. The amplitude of this wave, measured from the middle of the wave (the equator), is 30° of latitude. Recall that the 30th parallels are ½ of the height of each hemisphere, or ½ of the radius of the Earth.

Since the height of the wave is equal to ½ of the Earth’s radius, the ratio between the wavelength and it’s amplitude is 4π. Measuring the amplitude from the top of the wavelength to the bottom (from 30° N to 30° S), the amplitude is equal to the radius of the Earth, and the ratio between the wavelength and the amplitude is 2π."

--"The old urban centers on the Eastern Seaboard of the U.S are in nearly perfect alignment.

This great circle line crosses through the middle of Washington DC and the middle of Boston, and it crosses right over the middle of New York City. It also crosses over Philadelphia and the Baltimore waterfront. The azimuth of this line as it crosses over NYC is 52°, which is also the angle of the sides of the Great Pyramid.

The alignment crosses between Teotihuacan and Cholula in Mexico and just as this alignment crosses into Mexico from the gulf it crosses over the ancient city of El Tajin and the pyramid of niches. The alignment also crosses over Baalbek, Lebanon and just north of the ancient city of Troy. The alignment also crosses over Stonehenge. The azimuth of the alignment as it crosses over Stonehenge is 72° west of due north and 72° east of due south, which is not the same as the primary alignment of Stonehenge itself. However, the alignment from the center of Stonehenge to the center of the heel stone is 52° east of due north, which is the same as the azimuth of this global alignment as it crosses over New York City and the same as the angle of the Great Pyramid.

In addition to the cities on the Eastern Seaboard and the ancient sites listed above, this alignment also crosses over a number of other major cities of the modern era, including Mexico City, the national capital of Mexico; Mobile, Alabama; Atlanta, Georgia; London, the national capital of England; Lille, France, Stuttgart and Munich in southern Germany; Zagreb, the national capital of Croatia; Belgrade, the national capital of Serbia; Sofia, the national capital of Bulgaria; Beirut, the national capital of Lebanon; Damascus, the national capital of Syria; and Riyadh, the national capital of Saudi Arabia."

posted in Cosmology - 0 replies

Possible Miniature Solar System Discovered

2005-11-30T07:46:47Z

http://news.yahoo.com/s/ap/20051130/ap_on_sc/tiny_solar_system

LOS ANGELES - Astronomers have discovered what they believe is the birth of the smallest known solar system. Peering through ground- and space-based telescopes, scientists observed a brown dwarf — or failed star — less than one hundredth the mass of the sun surrounded by what appears to be a disk of dust and gas.

The brown dwarf — located 500 light years away in the constellation Chamaeleon — appears to be undergoing a planet-forming process that could one day yield a solar system, said Kevin Luhman of Pennsylvania State University, who led the discovery.

It's long been believed that our own solar system came into existence when a huge cloud of gas and dust collapsed to form the sun and planets about 4.5 billion years ago.

The new finding is the smallest brown dwarf to be discovered with planet-forming properties. If the disk forms planets, the resulting solar system will be about 100 times smaller than our own, scientists said.

Brown dwarfs, which are bigger than a planet but much smaller than a star, are thought to be balls of gas that failed to collect enough mass to start shining.

The discovery was made using NASA's Spitzer Space Telescope and Hubble Space Telescope as well as ground observatories. Results will be published in the Dec. 10 issue of the Astrophysical Journal Letters.

posted in Cosmology - 0 replies

Stunning photo previews the death of our Sun

2005-11-26T11:07:52Z

In the process the star casts off an ethereal envelope of gas in concentric shells - the formation of these shells are still a mystery to astronomers and this image is part of new data that will help them to advance our understanding of the phenomenon.

It is thought that when our Sun has used up all its hydrogen fuel in 4-5 billion years it will meet a similar fate.

The image was taken at the Gemini North Telescope in Hawaii. Gemini operates twin telescopes that are two of the largest in the world. For this image, astronomers used the newly upgraded ALTAIR adaptive optics system which helps them correct any distortion of light due to the atmosphere (the effect that makes stars appear to twinkle).

Image Credit: Gemini Observatory/Travis Rector, University of Alaska Anchorage

Source: PPARC

http://www.physorg.com/news8472.html

posted in Cosmology - 0 replies

1,400-Pound Meteorite Found in Kansas

2005-11-12T17:44:09Z

http://www.sfgate.com/cgi-bin/article.cgi?file=/n/a/2005/11/11/national/a134604S54.DTL

(11-11) 13:46 PST Greensburg, Kan. (AP) --

In an area of southwest Kansas long known for its meteorite finds, Steve Arnold came up with what may be the biggest of its kind ever found in the United States.

Arnold, a professional meteorite hunter from Kingston, Ark., found the 1,400-pound space rock two weeks ago in Kiowa County's Brenham Township. Using a metal detector mounted on a three-wheel vehicle, he discovered it more than 7 feet underground and dug it up.

It was in the same area that in 1949 produced a 1,000-pound meteorite now on display at the Celestial Museum in Greensburg, part of the World's Largest Hand Dug Well that is the community's biggest claim to fame.

"It is aesthetically the type of meteorite that makes collectors drool," Arnold, a former Wichita resident who has hunted for meteorites around the world, said of his find. "It's what a meteorite ought to look like. It's going to make first-graders go 'Wow!'"

Arnold estimates the value of the big rock "in the seven figures" and says he wants to sell it, preferably to a museum or someone who will keep it intact.

"It won't be cut to reveal its inner beauty," he said. "It's awesome enough from the outside."

Geoffrey Notkin, a science writer and meteorite collector who was with Arnold when the meteorite was found, said its size alone makes it extraordinary.

"By sheer mass, it has to be one of the largest finds in decades," he said.

According to the American Museum of Natural History in New York, the Brenham meteorite exploded centuries ago over what is now Kansas, scattering more than three tons of fragments.

"We get regular reports of meteorites," said Rex Buchanan, associate director of the Kansas Geological Survey. "People see them and they bring them in. A normal size is anywhere from the size of your fist to a grapefruit."

The meteorite Arnold discovered is classified as an oriented pallasite, so it has a conical shape and has olivine crystals embedded in iron-nickel alloy. Only two larger ones of that type are known to have been found: a 3,100-pounder in Australia and a 1,500-pounder in Argentina.

Meteorites change shape as they enter the Earth's atmosphere. An oriented meteorite, which is rare, maintains a stable flight rather than tumbling.

Richard Stephenson, manager of the Big Well, said the majority of meteorites found in Kiowa County are from a two-square mile area in Brenham Township. The Kiowa County meteorites are known throughout the world for gemlike olivine crystals, and they look almost like stained glass when cut.

posted in Cosmology - 0 replies

The Michelson and Morley 1887 Experiment and the Discovery of Absolute Motio

2005-11-09T20:34:07Z

http://lanl.arxiv.org/PS_cache/physics/pdf/0508/0508174.pdf

posted in Cosmology - 0 replies

gravity probe b

2005-11-04T22:15:47Z

this has me ROTFL-

http://www.gravityprobeb.com/

Just to get this straight...

The failure to detect frame dragging led to Special Relativity...which led to General Relativity...which predicts the frame dragging Gravity Probe B is supposed to detect!

posted in Cosmology - 2 replies

New evidence of massive black hole in our galaxy

2005-11-03T01:09:39Z

http://today.reuters.com/news/NewsArticle.aspx?type=scienceNews&storyID=2005-11-02T182526Z_01_YUE264875_RTRUKOC_0_US-SPACE-BLACKHOLE.xml

LONDON (Reuters) - Chinese scientists said on Wednesday they had gathered evidence that shows a giant object in the center of our galaxy is a super-massive black hole.

Zhi-Qiang Shen and researchers at the Shanghai Astronomical Observatory captured radio waves emitted just beyond the edge of the mysterious object, known as Sagittarius A, with a system of 10 radio telescopes spread across the United States.

In a report in the science journal Nature they said it "provides strong evidence that Sgr A is a super-massive black hole."

The celestial objects that suck in everything around them including light are among the most mysterious objects in the universe. They are formed when matter from a dying star collapses under its own gravity.

Black holes have been described as the ultimate victory over gravity because of their ability to suck in stars and other galactic features.

Scientists have long suspected the presence of a black hole in the center of the Galaxy. Astronomers believe it is four million times more massive than our Sun.

The research reported in Nature suggests the black hole is as wide as the radius of the Earth's orbit.

"These observations provide strong evidence that Sgr A is indeed a black hole, and afford a glimpse of the behavior of the matter that is about to flow into it," said Christopher Reynolds, of the University of Maryland in the United States, in a commentary in the journal.

He described the findings as a further step toward capturing an image of the shadow around the edge of a black hole, which would be a classic test of Albert Einstein's general theory of relativity.

The theory predicts that massive bodies -- planets, stars or black holes -- actually twist time and space around as they spin.

© Reuters 2005. All Rights Reserved.

posted in Cosmology - 0 replies

Cosmological natural selection

2005-10-26T00:28:16Z

http://en.wikipedia.org/wiki/Cosmological_natural_selection

An interesting hypothesis explaining why the universe seems "designed" to support our type of life (and black holes!). It suggests there are an unlimited other universes created though black holes. Each universe has randomly different cosmological constants for matter and energy. This then explains why the constants for our universe add up to create life. Because there are essentially infinite others that do not.

While just a hypothesis, it makes a lot of sense.

posted in Cosmology - 0 replies

Short gamma-ray bursts mystery possibly solved

2005-10-06T05:58:34Z

http://www.space.com/scienceastronomy/051005_short_bursts.html

The most intense explosions in the universe come in two varieties. One type lasts several seconds, and the others are gone in less than a second.

Until now, astronomers had not pinned down the sources of the short-duration bursts.

New observations show convincingly that they are created by collisions of two very dense objects, likely neutron stars or a neutron star and a black hole, as theory had predicted.

The results solve a 35-year-old mystery.

Hard to spot

The explosions are called gamma-ray bursts, or GRBs. Several are recorded every day, coming from all directions of the sky.

Most originate in the very distant universe. One nearby could trigger a mass extinction on Earth.

Gamma rays are the most intense form of radiation, more powerful than X-rays. The afterglow of a single burst, measured in X-rays, radio waves and other wavelengths, can be billions of times brighter than the entire galaxy in which it originates.

Long-duration GRBs typically last about 20 seconds. Previous studies revealed one of these is released when the core of a young and very massive star collapses in a supernova event.

"Gamma-ray bursts in general are notoriously difficult to study, but the shortest ones have been next to impossible to pin down," said Neil Gehrels of NASA Goddard Space Flight Center. "All that has changed. We now have the tools in place to study these events."

posted in Cosmology - 0 replies

Cassini finds changes in Saturn's rings

2005-10-03T05:49:47Z

New observations by the international Cassini spacecraft reveal that Saturn's trademark shimmering rings, which have dazzled astronomers since Galileo's time, have dramatically changed over the past 25 years.

Among the most surprising findings is that parts of Saturn's innermost ring — the D ring — have grown dimmer since the Voyager spacecraft flew by the planet in 1981. A piece of the D ring also has shifted, moving 125 miles inward toward Saturn.

While scientists puzzle over what caused Saturn's D ring to change in such a short period, the observations could tell something about the age and lifetime of planetary rings.

[continued from link]

http://www.sfgate.com/cgi-bin/article.cgi?file=/news/archive/2005/09/05/state/n120553D08.DTL

posted in Cosmology - 1 reply

Websites to recommend:

2005-09-25T15:52:47Z

http://www.bbc.co.uk/science/space/spaceguide/skyatnight/

and the magazine that accompanies it:

http://www.skyatnightmagazine.com/Default.asp?bhcp=1

posted in Cosmology - 0 replies

telescope repair?

2005-09-25T06:27:34Z

Hi- I live in San Luis Obispo and am trying to find a repair shop for my telescope. A part from the eye piece has broken or come loose. Does anybody know a place to take it. I found there is one in Monterey, but am looking for a closer one.
thanks
leslie

posted in Cosmology - 0 replies

Astronomers Discover Bright Quasar Without Massive Host Galaxy

2005-09-17T03:51:55Z

http://www.eso.org/outreach/press-rel/pr-2005/pr-23-05.html

Black Hole in Search of a Home

An international team of astronomers used two of the most powerful astronomical facilities available, the ESO Very Large Telescope (VLT) at Cerro Paranal and the Hubble Space Telescope (HST), to conduct a detailed study of 20 low redshift quasars. For 19 of them, they found, as expected, that these super massive black holes are surrounded by a host galaxy. But when they studied the bright quasar HE0450-2958, located some 5 billion light-years away, they couldn't find evidence for an encircling galaxy. This, the astronomers suggest, may indicate a rare case of collision between a seemingly normal spiral galaxy and a much more exotic object harbouring a very massive black hole.

With masses up to hundreds of millions that of the Sun, "super massive" black holes are the most tantalizing objects known. Hiding in the centre of most large galaxies, including our own Milky Way (see ESO PR 26/03), they sometimes manifest themselves by devouring matter they engulf from their surroundings. Shining up to the largest distances, they are then called "quasars" or "QSOs" (for "quasi-stellar objects"), as they had initially been confused with stars.

Decades of observations of quasars have suggested that they are always associated with massive host galaxies. However, observing the host galaxy of a quasar is a challenging work, because the quasar is radiating so energetically that its host galaxy is hard to detect in the flare.

posted in Cosmology - 0 replies

Pulsar moving at 1100km/s is leaving galaxy

2005-09-04T00:03:41Z

http://www.newscientistspace.com/article.ns?id=dn7934

Astronomers have spotted the fastest moving stellar corpse to date – and it appears to be headed straight out of our galaxy.

A team from the US National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, US, clocked the dead star at 1100 kilometres per second.

posted in Cosmology - 0 replies

New data suggests the Milky Way is a barred spiral galaxy

2005-08-17T18:32:09Z

http://www.news.wisc.edu/11405.html

With the help of NASA's Spitzer Space Telescope, astronomers have conducted the most comprehensive structural analysis of our galaxy and have found tantalizing new evidence that the Milky Way is much different from your ordinary spiral galaxy.

The survey using the orbiting infrared telescope provides the fine details of a long central bar feature that distinguishes the Milky Way from more pedestrian spiral galaxies.

"This is the best evidence ever for this long central bar in our galaxy," says Ed Churchwell, a UW-Madison professor of astronomy and a senior author of a paper describing the new work in an upcoming edition of Astrophysical Journal Letters, a leading astronomy journal.

Using the orbiting infrared telescope, the group of astronomers surveyed some 30 million stars in the plane of the galaxy in an effort to build a detailed portrait of the inner regions of the Milky Way. The task, according to Churchwell, is like trying to describe the boundaries of a forest from a vantage point deep within the woods: "This is hard to do from within the galaxy."

Spitzer's capabilities, however, helped the astronomers cut through obscuring clouds of interstellar dust to gather infrared starlight from tens of millions of stars at the center of the galaxy. The new survey gives the most detailed picture to date of the inner regions of the Milky Way.

"We're observing at wavelengths where the galaxy is more transparent, and we're bringing tens of millions of objects into the equation," says Robert Benjamin, the lead author of the new study and a professor of physics at the University of Wisconsin-Whitewater.

The possibility that the Milky Way Galaxy has a long stellar bar through its center has long been considered by astronomers, and such phenomena are not unheard of in galactic taxonomy. They are clearly evident in other galaxies, and it is a structural characteristic that adds definition beyond the swirling arms of typical spiral galaxies.

The new study provides the best estimates for the size and orientation of the bar, which are far different from previous estimates.

It shows a bar, consisting of relatively old and red stars, spanning the center of the galaxy roughly 27,000 light years in length - 7,000 light years longer than previously believed. It also shows that the bar is oriented at about a 45-degree angle relative to a line joining the sun and the center of the galaxy.

Previously, astronomers debated whether a presumed central feature of the galaxy would be a bar structure or a central ellipse - or both. The new research, the Wisconsin astronomers say, clearly shows a bar-like structure.

"To date, this is the best evidence for a long bar in our galaxy," Benjamin asserts. "It's hard to argue with this data."

The Spitzer Space Telescope was lofted into orbit in August of 2003. It consists of a telescope and three science instruments, including the Infrared Array Camera, the primary instrument used for the new survey, known as GLIMPSE for Galactic Legacy Mid-Plane Survey Extraordinaire.

NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington, D.C. Science operations are conducted at the Spitzer Science Center in Pasadena. JPL is a division of the California Institute of Technology.

posted in Cosmology - 0 replies

Help Solve the Mystery of the Pioneer Anomaly

2005-07-25T18:59:36Z

http://science.slashdot.org/article.pl?sid=05/07/25/114239&tid=160&tid=14

"Very soon, NASA will be dismantling and scrapping its only computer left which is able to access and process the data on its ancient 7- and 9-track magnetic tapes. "Who cares", you say? Well, the Planetary Society for one and they're hoping you might care as well. The data held on these (few hundred) tapes is no ordinary forgettable data, it is the complete archive of the first 15 years of all the data returned to Earth by the Pioneer spacecraft which were sent into interstellar space. This additional and thus far unexamined data (the data after 1988 is available and has already been examined) may hold the key to solving what is considered one of the top problems in physics today, the so called Pioneer anomaly, where the observed trajectory of these spacecraft (and a couple others) deviates noticeably from our very precise expectation. The reason for the anomaly may be as mundane as uneven radiation pressure or escaping thruster fuel or it may be as groundbreaking as a clue to completely new physics, perhaps related to dark matter or dark energy. The Planetary Society is planning on recovering this data and poring over it meticulously to look for something which may have been missed or hidden from current investigations into the phenomenon. They need money to do this, about $250,000, and are asking for donations to fund the project. You do not need to be a member to donate. There are no serious proposals to send any more spin-stabilized spacecraft on solar escape trajectories any time in the near future and this is probably the only tenable method we have to directly investigate this mystery in the interim."

posted in Cosmology - 0 replies

Ice ages maybe linked to galactic position

2005-07-25T18:57:49Z

It might sound preposterous, like astrology, to suggest that galactic events help determine when North America is or isn't buried under immense sheets of ice taller than skyscrapers. But new research suggests the coming and going of major ice ages might result partly from our solar system's passage through immense, snakelike clouds of exploding stars in the Milky Way galaxy.

...

[continued from link]

http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/07/25/MNGCIDSL4R1.DTL

posted in Cosmology - 0 replies

A Dangerous New Kind of Solar Storm

2005-07-15T01:08:44Z

http://science.nasa.gov/headlines/y2005/10jun_newstorm.htm

June 10, 2005: January 2005 was a stormy month--in space. With little warning, a giant spot materialized on the sun and started exploding. Between January 15th and 19th, sunspot 720 produced four powerful solar flares. When it exploded a fifth time on January 20th, onlookers were not surprised.

They should have been. Researchers realize now that the January 20th blast was something special. It has shaken the foundations of space weather theory and, possibly, changed the way astronauts are going to operate when they return to the Moon.

Sunspot 720 unleashed a new kind of solar storm.

see captionScant minutes after the January 20th flare, a swarm of high-speed protons surrounded Earth and the Moon. Thirty minutes later, the most intense proton storm in decades was underway.

"We've been hit by strong proton storms before, but [never so quickly]," says solar physicist Robert Lin of UC Berkeley. "Proton storms normally develop hours or even days after a flare." This one began in minutes.

Audio description:
http://science.nasa.gov/headlines/y2005/images/newstorm/audio/story.m3u

posted in Cosmology - 1 reply

* Third Orbit Thursday -- June 16th, 2005 in San Francisco, CA *

2005-06-16T00:06:52Z

Hi there,

Care to meet in person, over drinks, to discuss how people might sustainably provide something to look forward to for the world's populations by travelling into space and really beginning the era of space colonization? How might development in sustainable technology be influenced by the stresses of existence in space? Are there particular areas that might constitute "low-hanging fruit" for companies wishing to bypass government slowness by making the first space colonies a private endeavour? Or is public-private partnership the answer? Or does capitalism belong on Earth, not in space? How about nuclear (fission or fusion? vs. solar (photovoltaic or catching the solar wind)? What do you think?

Come on down to Sublounge this Thursday, June 16th, 2005 (tommorrow night as I write this) to discuss these topics and more!

WHERE:
Sublounge is a funky little pad at 628 20th St. @ 3rd St., in San Francisco between Potrero Hill and the bay.

WHAT:
Third Orbit Thursday is a free event held on, you guessed it, the third Thursday of every month. It's an opportunity to bring together people interested in space travel, sustainable development, alternative communities and burning man to have a social hour over cocktails. Musical hosts will provide good tunes to mellow out to, and there will be bartending staff at your service.

WHEN: ~9:30ish to sometime after midnight, after y'all take off. :-)

SPACECRAFT PARKING: Tons are available nearby. No shortage in this neighborhood.

cheers,
-Garlynn

posted in Cosmology - 0 replies

Astronomers have found the most Earthlike extrasolar planet discovered so far

2005-06-14T18:39:56Z

http://www.universetoday.com/am/publish/large_rocky_planet.html

posted in Cosmology - 0 replies

Recent study forces scientists to rethink basic law of physics

2005-05-12T17:46:53Z

http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/05/09/MNG5LCLEU41.DTL

Legislators change laws from time to time, but Mother Nature's laws are eternal -- or so it has seemed.

Now, though, scientists are debating clues that suggest the laws of physics change over time. University of California scientists are among the major players on both sides of the debate, which threatens to shake up our basic notions of reality.

At stake is one of the fundamental values in physics: the arcane-sounding "fine structure constant," which measures how subatomic particles interact with light and with each other.

Some astrophysicists have proposed that the value of the fine structure constant, a.k.a. "alpha," has changed subtly over billions of years. They base this proposal on their work -- using telescopes like the giant Keck telescope, which sits atop a dormant Hawaiian volcano -- analyzing light from interstellar gas and galaxy-gobbling super-furnaces called quasars on the outskirts of the universe.

posted in Cosmology - 0 replies

Bigger 'Birthmarks' In The Sky May Deflate Theory Of Cosmic Inflation

2005-04-22T16:06:08Z

http://www.spacedaily.com/news/cosmology-05s.html

Cool spaces in the cosmic microwave background - thought to be the 'birthmarks' of galaxies and clusters of galaxies - should be bigger than recently reported, according to a new analysis of satellite data by scientists at The University of Alabama in Huntsville (UAH).

This new analysis suggests that there is enough matter in the universe to bend light and other radiation as it travels through space, a finding that might deflate the current standard model of inflationary cosmology - how the universe is expanding and how much mass exists in that universe.

posted in Cosmology - 0 replies

NASA aims to hit, smash comet

2005-04-13T23:55:09Z

http://www.csmonitor.com/2005/0414/p25s01-stss.html

PASADENA CA – This year, NASA is planning a spectacular fireworks display on the Fourth of July. Unfortunately, you'll need a telescope to see it, as the explosions will take place over 268 million miles away. Obviously, this is far from the usual observances of our nation's birth. But NASA's plans do indeed have something to do with a birth: not just the birth of the United States, but our entire solar system.

I honestly have no idea if the timing of this mission is coincidence or not, but this July 4th, NASA is going to smash a comet, and observe the material that flies off in the explosion. The name of this mission is, appropriately enough, Deep Impact, and when it whops into the comet Tempel 1 this summer, the resulting smash will be equivalent to blowing up 4.8 tons of TNT, and is expected to blow a football stadium-sized crater about 7 stories deep into the dirty ice of the comet.

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On 'the 4th of July' no less. lol

posted in Cosmology - 0 replies

Mass extinction comes every 62 million years, UC physicists discover

2005-04-13T04:19:45Z

This is somewhat off topic but does have links to cosmological origins.

http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/03/10/MNGFIBN6PO1.DTL

With surprising and mysterious regularity, life on Earth has flourished and vanished in cycles of mass extinction every 62 million years, say two UC Berkeley scientists who discovered the pattern after a painstaking computer study of fossil records going back for more than 500 million years.

Their findings are certain to generate a renewed burst of speculation among scientists who study the history and evolution of life. Each period of abundant life and each mass extinction has itself covered at least a few million years -- and the trend of biodiversity has been rising steadily ever since the last mass extinction, when dinosaurs and millions of other life forms went extinct about 65 million years ago.

posted in Cosmology - 6 replies

Galactic pancake mystery solved

2005-04-09T18:16:01Z

http://news.bbc.co.uk/2/hi/science/nature/4422555.stm

Astronomers have figured out why a series of small galaxies surrounding the Milky Way are distributed around it in the shape of a pancake.

Theorists believed that the eleven dwarf galaxy companions should have a diffuse, spherical arrangement.

But a University of Durham team used a supercomputer to show how the galaxies could take the pancake form without challenging cosmological theory.

posted in Cosmology - 0 replies

Lawrence Livermore physicist: Black holes 'do not exist'

2005-04-05T00:11:44Z

http://www.nature.com/news/2005/050328/full/050328-8.html

Black holes are staples of science fiction and many think astronomers have observed them indirectly. But according to a physicist at the Lawrence Livermore National Laboratory in California, these awesome breaches in space-time do not and indeed cannot exist.

posted in Cosmology - 2 replies

Space.com top 20 Hubble pictures

2005-03-29T20:00:39Z

http://www.space.com/bestimg/result.php?back=besthubble_exp_bubble_03.jpg&cat=hst

posted in Cosmology - 6 replies

Craigslist gets beamed into space

2005-03-25T22:21:54Z

http://www.cnn.com/2005/TECH/space/03/23/craigslist.space/index.html

(SPACE.com) -- Aliens will be glad to know that if ever they need to find an apartment here on Earth, someone has got them covered.

On March 11, a company called Deep Space Communications Network beamed the first commercial transmission of a Web site into space.

The message? Over one hundred thousand separate postings from craigslist.org, the popular community Web site that includes classified listings for jobs, housing and other goods. The transmission included a date and time stamp, as well as an audio track identifying the message as originating from Earth.

posted in Cosmology - 0 replies

Planet Light Spotted From Beyond Solar System

2005-03-22T22:05:49Z

http://story.news.yahoo.com/news?tmpl=story&u=/ap/planetary_light

A NASA telescope peering far beyond our solar system has for the first time directly measured light from two Jupiter-sized gas planets closely orbiting distant stars, adding crucial features to astronomy's portrait of faraway worlds.

---

This is actually a historic moment in cosmology, IMO.

posted in Cosmology - 0 replies

13 things that do not make sense

2005-03-21T06:21:42Z

http://www.newscientist.com/channel/space/mg18524911.600

Many of the 13 are cosmological questions. :-)

posted in Cosmology - 0 replies

Nobel Prize winner Hans Bethe dies at age 98

2005-03-08T18:12:31Z

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/03/08/BAG5DBLTG41.DTL

Hans Bethe, the last of the giants of 20th century physics who explained the energy source that powers the stars and helped develop the atom bomb, but devoted decades of his life to nuclear arms control and campaigns against space-based weaponry, died Sunday night at his home in Ithaca, N.Y.

He was 98, a Nobel laureate and one of the most admired figures in modern science.

...Nearly 70 years ago, Professor Bethe published a seminal paper announcing that the fusion of hydrogen and helium atoms in stars like the sun was the source of their energy and light. The discovery won him the Nobel Prize nearly 30 years later, and while it also helped inspire Edward Teller to conceive of the hydrogen bomb, it also led to the long and bitter enmity between the two scientists who were once close friends.

posted in Cosmology - 0 replies

Spitzer Space Telescope Finds Bright Infrared Galaxies

2005-03-05T21:34:32Z

http://www.spacedaily.com/news/cosmology-05g.html

A Cornell University-led team operating the Infrared Spectrograph (IRS), the largest of the three main instruments on NASA's Spitzer Space Telescope, has discovered a mysterious population of distant and enormously powerful galaxies radiating in the infrared spectrum with many hundreds of times more power than our Milky Way galaxy.

Their distance from Earth is about 11 billion light years, or 80 percent of the way back to the Big Bang.

posted in Cosmology - 0 replies

Book: When Theories Collide

2005-03-05T08:37:05Z

http://www.rednova.com/news/display/?id=131908#

I HAD better declare an interest right away. Simon Singh is the British author of the 1997 book Fermat's Last Theorem, after the publication of which the phrase "math best-seller" was no longer an oxymoron. He thus opened up for lesser drudges the opportunity to actually make some money by writing popular books about mathematics, an opportunity I myself have seized upon gratefully. In spite of some minor issues I had with the Fermat book, I am therefore well disposed towards Singh, and picked up his latest production determined to give it the benefit of any possible doubt.

In the event, I don't think there is much doubt. Big Bang is a thoroughly excellent popular history of scientific cosmology, most of it dealing with the 20th century, which is when most of the important developments in this field occurred. It is written in a plain narrative style, with a minimum of difficult math, and two neat pages of summary notes at the end of each of the five main chapters. There are lively character sketches of the principal players, and some amusing anecdotes; but the author's main aim is to tell us how we reached the present state of fair consensus (there is rarely a total consensus on large scientific theories) about the structure and history of the universe at large.

As well as the particular story he has to tell, Singh gives some fine, illuminating descriptions of what happens when theories collide. Three times in the history of this topic it has been the case that two competing theories, each of roughly equal plausibility, have contended for supremacy. In showing how, in each case, the better theory won, Singh gives the general reader a valuable lesson in the progress of scientific inquiry, in the nature of scientific method and the means by which controversies in science are resolved. A great deal of nonsense is talked and written about this, particularly by anti-evolution propagandists. Singh's account shows plainly that the generality of scientists are neither passionless Mister Spocks, weighing evidence with cold, flawless objectivity, nor grim upholders of a pseudo-religious dogma determined to defend crumbling theories to the last ditch. They are human beings, equipped with the usual proportions of weaknesses and prejudices, reluctant to let go of the convictions of a lifetime, but usually willing to do so when faced with convincing evidence.

posted in Cosmology - 0 replies

Peek into deep space could rewrite history of Universe

2005-03-03T23:37:40Z

http://story.news.yahoo.com/news?tmpl=story&u=/afp/spaceastronomyuniverse

PARIS (AFP) - The discovery of a rich cluster of hundreds -- possibly thousands -- of galaxies in deep space suggests the Universe evolved into its present form far sooner than was once thought, space agencies announced.

posted in Cosmology - 0 replies

Unknown Force Triggers Star Formation

2005-03-02T06:33:57Z

http://www.space.com/scienceastronomy/proto_stars_050301.html

"The best look ever inside a womb of star birth reveals a force at work astronomers were not aware of.

Like a baby's first ultrasound, scientists peered into a stellar envelope to capture the earliest and most detailed view of a collapsing cloud of gas and dust, NASA announced Tuesday. The images were made mostly with the European Space Agency's XMM-Newton X-ray observatory.

Some previously unrealized energetic process, likely related to magnetic fields, is superheating parts of the cloud, nudging it to become a star, scientists said.

The detection of X-rays from the cold stellar precursor surprised astronomers. The observations reveal that matter is falling toward the core 10 times faster than gravity could account for."

posted in Cosmology - 0 replies

Dark matter alternative theory

2005-03-01T01:26:05Z

http://www.space.com/scienceastronomy/dark_energy_050228.html

"WASHINGTON, D.C. - Scientists may not have to go over to the dark side to explain the fate of the universe.

The theory that the accelerated expansion of the universe is caused by mysterious "dark energy" is being challenged by New York University physicist Georgi Dvali. He thinks there's just a gravity leak."

posted in Cosmology - 0 replies

First Invisible Galaxy Discovered in Cosmology Breakthrough

2005-02-24T04:29:20Z

http://www.space.com/scienceastronomy/050223_dark_galaxy.html

Possible 'dark matter' galaxy.

posted in Cosmology - 0 replies

'Pack ice' suggests frozen sea on Mars

2005-02-21T20:38:57Z

http://www.newscientist.com/article.ns?id=dn7039

A frozen sea, surviving as blocks of pack ice, may lie just beneath the surface of Mars, suggest observations from Europe's Mars Express spacecraft. The sea is just 5° north of the Martian equator and would be the first discovery of a large body of water beyond the planet's polar ice caps.

posted in Cosmology - 0 replies

Monster star burst was brighter than full Moon: astronomers

2005-02-19T00:26:18Z

http://story.news.yahoo.com/news?tmpl=story&u=/afp/astronomyspaceflare

"PARIS (AFP) - Stunned astronomers described the greatest cosmic explosion ever monitored -- a star burst from the other side of the galaxy that was briefly brighter than the full Moon and swamped satellites and telescopes."

A very interesting cosmological event!

posted in Cosmology - 0 replies