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Enlarge Left panel: Air molecules whiz around at a variety of speeds, and some are very fast. When they collide with both heavy and light elements - for example, xenon (purple) and silicon (orange) - these fast moving particles have enough momentum to affect both nuclei. Right panel: Dark matter particles are moving more slowly and are less able to affect the heavy xenon nucleus. As a result, detectors made from lighter materials like silicon may prove to be more effective at picking up signals of dark matter. Credit: Greg Stewart/SLAC National Accelerator Laboratory (Phys.org) —Now that it looks...

Try using the entire Earth to hunt for a new fundamental force of nature. So say Larry Hunter of Amherst College in Massachusetts, and colleagues. They have created a map of the spins of electrons deep within the Earth's mantle, which could be used to reveal the as-yet-unseen force as well as the strange particles – known as "unparticles" – that might carry it. We currently know of four fundamental forces: gravity, electromagnetism and the strong and weak nuclear forces. The hypothetical fifth force can be thought of as a version of magnetism that does not weaken as quickly with...

3D image shows ginormous filament of Big Bang batter Dark matter can't really be "seen" as such, it can only be detected by looking at the gravitational effects it has on the space around it. But by collating images from the Hubble Space telescope, the researchers now have a picture of dark matter (shown in blue above) extending 60 million light-years away from one of the most massive galaxy clusters astrophysicists know about – MACS J0717. Big Bang theories predict that when the universe was first created, dense matter condensed into a web of tangled dark matter filaments throughout the...

A re-analysis of radio telescope observations from three countries has yielded a surprising result: nearby galaxies harbour one-third more hydrogen than had previously been estimated. While nothing like enough matter to solve physics’ “dark matter” problem, the work by CSIRO astronomer Dr Robert Braun (chief scientist at the agency’s Astronomy and Space Science division in Sydney) also helps explain why the rate of star formation has slowed down. While there’s more hydrogen than astronomers had thought, its distribution makes star formation more difficult. Andromeda – the galaxy headed for a catastrophic collision with our own in about four billion years...

Analysis of data from the National Science Foundation-(NSF) funded 10-m South Pole Telescope (SPT) in Antarctica provides new support for the most widely accepted explanation of dark energy, the source of the mysterious force that is responsible for the accelerating expansion of the universe. The results begin to hone in on the tiny mass of the neutrinos, the most abundant particles in the universe, which until recently were thought to be without mass. The SPT data strongly support Albert Einstein's cosmological constant—the leading model for dark energy—even though researchers base the analysis on only a fraction of the SPT data...

Astronomers have measured the precise distance to over a quarter of a million galaxies to gain new insights into a key period in cosmic history. The 3D map of the sky allows scientists to probe the time six billion years ago when dark energy became the dominant influence on the Universe's expansion. No-one knows the true nature of this repulsive force, but the exquisite data in the international BOSS survey will help test various theories. The analysis appears in six papers. These have all been posted on the arXiv preprint server. "This is an incredibly exciting time to be working...

Scientists' predictions about the mysterious dark matter purported to make up most of the mass of the Universe may have to be revised.Research on dwarf galaxies suggests they cannot form in the way they do if dark matter exists in the form that the most common model requires it to. That may mean that the Large Hadron Collider will not be able to spot it. Leading cosmologist Carlos Frenk spoke of the "disturbing" developments at the British Science Festival in Bradford. The current theory holds that around 4% of the Universe is made up of normal matter - the stuff...

First results from a major astronomical survey have confirmed the existence of mysterious dark energy using a cutting-edge technique. Dark energy makes up some 74% of the Universe and its existence explains why the Universe appears to be expanding at an accelerating rate. The finding was based on studies of more than 200,000 galaxies. Scientists used two separate kinds of observation to provide an independent check on previous dark energy results. Two papers by an international team of researchers have been accepted for publication in the Monthly Notices of the Royal Astronomical Society journal. One type of observation used by...

Is an Adjacent Universe Causing the Dark Flow of Hundred of Millions of Stars at the Edge of the Observable Universe? Or, Might It Be Something ElseBack in the Middle Ages, maps showed terrifying images of sea dragons at the boundaries of the known world. Today, scientists have observed strange new motion at the very limits of the known universe -- kind of where you'd expect to find new things, but they still didn't expect this. A huge swathe of galactic clusters seem to be heading to a cosmic hotspot and nobody knows why. The unexplained motion has hundreds of...

Researchers have developed a simple technique that adds evidence to the theory that the Universe is flat. Moreover, the method - developed by revisiting a 30-year-old idea - confirms that "dark energy" makes up nearly three-quarters of the Universe. The research, published in Nature, uses existing data and relies on fewer assumptions than current approaches. Author Christian Marinoni says the idea turns estimating the Universe's shape into "primary school" geometry. While the idea of the Earth being flat preoccupied explorers centuries ago, the question of whether the Universe itself is flat remains a debatable topic. The degree to which the...

Today physicists announced that they may have found the key to explaining dark matter in the universe. It all has to do with the potential discovery of a "sterile neutrino." According to a release about the new study: Neutrinos are neutral elementary particles born in the radioactive decay of other particles. The known "flavors" of neutrinos are the neutral counterparts of electrons and their heavier cousins, muons and taus. Regardless of a neutrino's original flavor, the particles constantly flip from one type to another in a phenomenon called "neutrino flavor oscillation." An electron neutrino might become a muon neutrino, and...

British scientists have claimed that the method used to calculate the make-up of the universe may be wrong. The universe as we know it -- formed of recognisable components such as planets, stars, asteroids and gas -- accounts for just four per cent of the cosmos, according to the decades old Standard Model. The rest is thought to be made up of mysterious dark matter and dark energy. This permeates space and powers the expansion of the universe. But physicists at Durham University now claim the calculations on which the Standard Model is based could be fatally flawed. This raises...

Scientists announced Thursday that they believe they have detected evidence of dark matter in data collected at an underground physics lab in Soudan... According to the Department of Energy's Fermilab, which is conducting the search for dark matter at the Soudan lab, "judging by the way galaxies rotate, scientists have known for 70 years that the matter we can see does not provide enough gravitational pull to hold the galaxies together. There must exist some form of matter that does not emit or reflect light." In the announcement, the lab said the Cryogenic Dark Matter Search experiment has "detected...

What if the discrepancy arises from a flaw in our theory of gravity rather than from some provider of mass that we cannot see? In the 1980s physicist Mordehai Milgrom of the Weizmann Institute of Science in Rehovot, Israel, proposed a modification to Newtonian dynamics that would explain many of the observational discrepancies without requiring significant mass to be hidden away in dark matter. But it fell short of describing all celestial objects, and to incorporate the full span of gravitational interactions, a modification to Albert Einstein's theory of general relativity is needed. A review article in the November 6...

Imagine a time when the entire universe froze. According to a new model for dark energy, that is essentially what happened about 11.5 billion years ago, when the universe was a quarter of the size it is today. The model, published online May 6 in the journal Physical Review D, was developed by Research Associate Sourish Dutta and Professor of Physics Robert Scherrer at Vanderbilt University, working with Professor of Physics Stephen Hsu and graduate student David Reeb at the University of Oregon. A cosmological phase transition -- similar to freezing -- is one of the distinctive aspects of this...

As modern cosmologists rely more and more on the ominous "dark matter" to explain otherwise inexplicable observations, much effort has gone into the detection of this mysterious substance in the last two decades, yet no direct proof could be found that it actually exists. Even if it does exist, dark matter would be unable to reconcile all the current discrepancies between actual measurements and predictions based on theoretical models. Hence the number of physicists questioning the existence of dark matter has been increasing for some time now. Competing theories of gravitation have already been developed which are independent of this...

For the past quarter century, dark matter has been a mystery we've just had to live with. But the time may be getting close when science can finally unveil what this befuddling stuff is that makes up most of the matter in the universe. Dark matter can't be seen. Nobody even knows what it is. But it must be there, because without it galaxies would fly apart. Upcoming experiments on Earth such as the Large Hadron Collider (LHC) particle accelerator in Switzerland, and a new spacecraft called Gaia set to launch in 2011, could be the key to closing the...

Dark energy - the mysterious force that is speeding up the expansion of the Universe - has been a part of space for at least nine billion years. That is the conclusion of astronomers who presented results from a three-year study using the Hubble Space Telescope. The finding may rule out some competing theories that predict the strength of dark energy changes over time. Dark energy makes up about 70% of the Universe; the rest is dark matter (25%) and normal matter (5%). "It appears this dark energy was already boosting the expansion of the Universe as much as...

As if the mysteries of dark matter and dark energy weren't vexing enough, another baffling cosmic puzzle has been discovered. Patches of matter in the universe seem to be moving at very high speeds and in a uniform direction that can't be explained by any of the known gravitational forces in the observable universe. Astronomers are calling the phenomenon "dark flow." The stuff that's pulling this matter must be outside the observable universe, researchers conclude. When scientists talk about the observable universe, they don't just mean as far out as the eye, or even the most powerful telescope, can see....

Tsunami invisibility cloak, dark energy v. the void, sorting nanotubes with light, and moreNews from the American Physical SocietyTsunami Invisibility Cloak M. Farhat, S. Enoch, S. Guenneau and A.B. Movchan Physical Review Letters (forthcoming) Rather than building stronger ocean-based structures to withstand tsunamis, it might be easier to simply make the structures disappear. A collaboration of physicists from the Centre National de la Recherche Scientifique (CNRS) and Aix-Marseille Universite in France and the University of Liverpool in England have conducted laboratory experiments showing that it's possible to make type of dike that acts as an invisibility cloak that hides off-shore...