Dark matter comes out of the cold

[Oscar the Cat]

Astronomers have for the first time put some real numbers on the physical characteristics of dark matter.

http://news.bbc.co.uk/1/hi/sci/tech/4679220.stm

[Rick]

US astronomers say they have found the first direct evidence for the mysterious stuff called dark matter.

Dark matter - which does not emit or reflect enough light to be "seen" - is thought to make up 25% of the Universe.

By contrast, the ordinary matter we can see is believed to make up no more than about 5% of our Universe.

More: http://news.bbc.co.uk/2/hi/science/nature/5272226.stm

[Rick]

Astronomers have found one of the best pieces of evidence for the existence of dark matter, a mysterious quantity that pervades our Universe.

They have identified what appears to be a ghostly ring in the sky which is made up of this enigmatic substance.

Using the Hubble Space Telescope, the scientists have established that the ring formed long ago after a colossal smash-up between two galaxy clusters.

More: http://news.bbc.co.uk/2/hi/science/nature/6657271.stm

[mickw]

A new map reveals dense pools of invisible matter tipping the scales at 10 trillion times the mass of the sun and housing a cosmic city of ancient galaxies.

The map, presented last week at a meeting of the American Astronomical Society in Austin, Texas, provides indirect evidence for so-called dark matter and how this mysterious substance affects galaxy formation.

Scientists theorize that dark matter, considered to make up about 85 percent of the universe's matter, acts as scaffolding on which galaxies mature. As the universe evolves, the tug from dark matter's gravitational field causes galaxies to collide and swirl into superclusters.

More: http://news.yahoo.com/s/space/20080117/sc_space/poolsofinvisiblemattermappedinspace

[mickw]

The identity of the mysterious dark matter thought to pervade the universe has eluded astrophysicists for decades. Now, for the first time a team hopes to look inside the sun for one of the prime candidates.

The invisible stuff called dark matter is thought to make up as much as 90 percent of the universe's matter. To date, astrophysicists have only inferred the existence of some mysterious substance by identifying its gravitational effects on visible matter such as stars and galaxies. (For instance, dark matter makes galaxies spin faster than otherwise expected.)

More:  http://www.space.com/scienceastronomy/080617-st-dark-matter.html

[Rick]

Scientists are pondering the possible source of an "unexpected surplus of cosmic ray electrons at very high energy", and suggest they're either pouring out of an exotic object relatively close to Earth or represent the fall-out from the annihilation of theoretical particles comprising dark matter.

The observation was made by the Advanced Thin Ionization Calorimeter (ATIC) project, led by boffins from Louisiana State University, which soared to 124,000 feet above Antarctica under a helium balloon "about as large as the interior of the New Orleans Superdome".

More: http://www.theregister.co.uk/2008/11/20/cosmic_ray_electrons/

[mickw]

Scientists are hot on the tail of one of nature's most elusive substances, the mysterious dark matter that is thought to make up the bulk of the universe. Many scientists think dark matter might even be hiding right under our noses here on Earth.

Dark matter is especially tricky to find because of its dark nature. In fact, scientists don't know what it is. It doesn't emit or reflect any light, so the most powerful telescopes have no hope of spying it directly. It has been thought to exist since the 1970s based on observations of gravity's effects on large-scales, such as among and between galaxies – regular matter can't account for the amount of gravity at work.

And dark matter doesn't often interact with most other matter, scientists theorize. One idea is that it flies right through the Earth, your house, and your body without bouncing off atoms

More:   Dark Matter

[mickw]

Dark matter and dark energy are two of the most mind-boggling ingredients in the universe. Ever since these concepts were first proposed, some astronomers have worked feverishly to figure out what each thing is, while other astronomers have tried to prove they don't exist, in hopes of restoring the universe to the more understandable place many would like it to be.

A new look at the data from one of the telescopes used to establish the existence of this strange stuff is causing some scientists to question whether they really exist at all. Yet other experts are holding firm to the idea that, whether we like it or not, the "dark side" of the universe is here to stay.

More:   No Matter

[Rick]

(Kind-of old, but couldn't find a link to the story in the forum...)

Thousands of physicists, astrophysicists, and astronomers are searching for dark matter, mysterious stuff whose gravity seems to hold the galaxies together. However, an old and highly controversial theory that simply changes the law of gravity can explain a key property of galaxies better than the standard dark matter theory, one astronomer reports. That claim isn't likely to win over many skeptics, but even some theorists who favor the standard theory say the analysis hands them a homework problem they should solve.

More: http://news.sciencemag.org/sciencenow/2011/02/more-evidence-against-dark-matte.html

[Rick]

Dark matter hunt nears final phase

Scientists could be nearing the final phase of the search for dark matter: the enigmatic substance thought to make up a quarter of our Universe.

The first results from a particle detector called LUX show it is the most powerful experiment of its kind.

It did not detect any dark matter during its first run, but scientists say it is poised to probe deeper than ever before during its second in 2014.

More: http://www.bbc.co.uk/news/science-environment-24733131