2011
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Blow for 'dark matter' theory as scientists find faint, undetected star
Tiny, faint star has mass one-fifth of our Sun Undetected stars could make up bulk of star clusters Blow for theory that 'dark matter' accounts for much of universe's mass By Rob Waugh UPDATED: 18:56 GMT, 22 December 2011 'Dark matter' is a theoretical - and controversial - substance which is undetectable by telescopes on earth, but thought by some scientists to account for up to three quarters of the mass of the whole universe. That theory received another blow today, as scientists detected a very low mass, faint star in a star cluster for the first time. The result means that the overall mass of such 'globular clusters' could well be explained without having to resort to dark matter. The M22 cluster, where a Swiss astronomer found a faint, previously undetected star.RECENT hints of a featherweight Higgs boson don't just take us nearer to a complete standard model of physics. The results affect a possible link between the Higgs and dark matter, the invisible stuff making up 80 per cent of the universe's matter. The Higgs is the last remaining hole in the standard model, the leading theory for how particles and forces interact. On 13 December, physicists at CERN near Geneva, Switzerland, presented data from the Large Hadron Collider suggesting Higgs bosons with a mass of 125 gigaelectronvolts (GeV) were made. The Higgs is detected by looking for suspicious excesses of particles that it might decay into.
What Higgs result means for dark matter conspiracy
An image taken by Kepler of star cluster NGC 6791, which is located 13,000 light years from Earth. The image has been color-coded so that brighter stars appear white, and fainter stars, red. Image credit: NASA/Ames/JPL-Caltech (PhysOrg.com) -- The primary objective of NASA’s Kepler satellite, which was launched in March 2009 to orbit the Sun, is to search for Earth-like planets in a portion of the Milky Way galaxy. But now a team of physicists has proposed that Kepler could have a second appealing purpose: to either detect or rule out primordial black holes (PBHs) of a certain mass range as the primary constituent of dark matter.
NASA satellite could reveal if primordial black holes are dark matter
Independent analyses of data from the Fermi Gamma-ray Space Telescope have found no trace of low-mass dark matter – the mysterious substance thought to make up much of the universe. The results appear to go against recent direct evidence for low-mass dark matter, although some physicists believe there is no conflict. Dark matter is an invisible substance thought to make up nearly a quarter of the mass/energy of the universe.
Latest Fermi studies find no trace of dark matter
New Study Throws Dark Matter Finding Into Question
A new study of dark matter, the mysterious hidden stuff thought to pervade the universe, casts doubt on a previous finding that offered hope that dark matter had finally been seen. In 2008, a European-Russian satellite called Payload for Antimatter Matter Exploration and Light nuclei Astrophysics (PAMELA) discovered a strange overabundance of particles called positrons, which are the antimatter counterpart to electrons. Matter and antimatter, which have the same mass but opposite charges, destroy one another when they meet.
Search for Elusive Dark Matter May Get Boost From New Galaxies | Andromeda Galaxy & Dwarf Galaxies | Structure of the Universe & Dark Energy
Astronomers have found two small galaxies that appear to circle our Milky Way's galactic neighbor Andromeda, and could shed new light on the mystery of dark matter in the universe, scientists say. The newfound dwarf galaxies, called Andromeda 28 and 29, are two of the most distant satellites galaxies from Andromeda ever detected. They are located about 600,000 light-years away from Andromeda, and approximately 1.1 million light-years from Earth, researchers said. The Andromeda galaxy is about 2.5 million light-years away and is the nearest spiral galaxy to the Milky Way. Like our galaxy, Andromeda is surrounded by numerous dwarf satellite galaxies.
Oct. 31, 2011 — Scientists all over the world are working feverishly to find the dark matter in the universe. Now researchers at Stockholm University have taken one step closer to solving the enigma with a new method. The universe is still a mystery. We know what about 5 percent of the universe consists of.
One step closer to dark matter in universe
Dark Matter Mystery Deepens
Like all galaxies, our Milky Way is home to a strange substance called dark matter. Dark matter is invisible, betraying its presence only through its gravitational pull. Without dark matter holding them together, our galaxy’s speedy stars would fly off in all directions. The nature of dark matter is a mystery — a mystery that a new study has only deepened.
Dark Matter: Now More Mysterious Than Ever
<img class="alignnone size-full wp-image-81258" title="Fornax_dwarf_galaxy" src="http://www.wired.com/images_blogs/wiredscience/2011/10/Fornax_dwarf_galaxy.jpg" alt="" width="660" height="660" /> Astronomers have one more reason to scratch their heads over the unseen material known as dark matter. Observations of two dwarf galaxies, Fornax and Sculptor, show the dark matter within them is spread out smoothly rather than heaped into a central bulge, contradicting cosmological models. Researchers know dark matter comprises a far greater percentage of the universe than the ordinary matter making up things like people and stars. Because of this, the distribution of dark matter determines the structure of the cosmos.Hubble survey carries out a dark matter census
Oct. 13, 2011 — Cluster MACS J1206.2-0847 (or MACS 1206 for short) is one of the first targets in a Hubble survey that will allow astronomers to construct the highly detailed dark matter maps of more galaxy clusters than ever before. These maps are being used to test previous but surprising results that suggest that dark matter is more densely packed inside clusters than some models predict. This might mean that galaxy cluster assembly began earlier than commonly thought.
Could primordial black holes be dark matter?
(PhysOrg.com) -- “We know that about 25% of the matter in the universe is dark matter, but we don’t know what it is ,” Michael Kesden tells PhysOrg.com . “There are a number of different theories about what dark matter could be, but we think one alternative might be very small primordial black holes.” When many of us think about black holes, we think of a huge cosmic event, sucking in everything around it. However, there is also the possibility of small black holes.How Dark Matter Messes with Our Galaxy
Space :: Web Exclusives :: September 20, 2011 :: :: Email :: Print One mystery solves another: dark matter explains the puzzling shape and environs of the Milky Way By George Musser Image: Illustration by Don Dixon Showcasing more than fifty of the most provocative, original, and significant online essays from 2011, The Best Science Writing Online 2012 will change the way...Sep. 19, 2011 — Scientists looking to capture evidence of dark matter -- the invisible substance thought to constitute much of the universe -- may find a helpful tool in the recent work of researchers from Princeton University and New York University. The team unveiled in a report in the journal Physical Review Letters this month a ready-made method for detecting the collision of stars with an elusive type of black hole that is on the short list of objects believed to make up dark matter. Such a discovery could serve as observable proof of dark matter and provide a much deeper understanding of the universe's inner workings.
Black hole, star collisions may illuminate universe's dark side
Dwarf galaxies suggest dark matter theory may be wrong
16 September 2011 Last updated at 17:47 GMT By Leila Battison Science reporter, Bradford Dwarf galaxies around the Milky Way are less dense than they should be if they held cold dark matter 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.Want to stay on top of all the space news? Follow @universetoday on Twitter Computer model of the Milky Way and its smaller neighbor, the Sagittarius dwarf galaxy.