Milky Way Galaxy. Image: NASA/JPL-Caltech

(PhysOrg.com) — 95%. That is the percentage of the known Universe that is missing. As in it is not there. Or at least if it is there, we can’t see it. We call this unseen stuff “dark matter”. That has been well known for sometime. What is trickier in answering is why? Why is it that 95% of the universe is made up of this so-named “dark matter?” An even trickier question is where? As in where is this dark matter? It is those two questions that have plagued physicists for decades. Dark matter, by its own definition cannot be seen, hence its name. So how do we “see” it, how do we know “where” to look?

Physicists have been trying to think of various “indirect” ways to “see” dark matter for decades. Now physicists at the Institute for Advanced Study in Princeton, NJ and the Max Planck Institute for Physics in Munich are ready to test their methods, The Economist reports.

Read complete article here. {via physorg.com}

Embedded in darkness (economist)

MOST of reality appears to be missing. Physicists reckon that the missing matter must be there, but that it is dark. Finding the stuff is damned tricky because dark matter, by definition, cannot be seen. So some of those physicists have been busy trying to devise ways of glimpsing it indirectly—and two groups of them now think their methods are ready to test.

One reason to believe dark matter exists is that galaxies rotate at such speeds that they would fly apart without it, or so the argument goes. The fact that galaxies persist suggests they are held together by the gravitational pull of something invisible—in other words, dark matter. This stops stars being shed from their edges.

Read complete article here. {via economist}

The Dark Matter Lab

SIOUX FALLS, S.D. (AP) — Far below the Black Hills of South Dakota, crews are building the world’s deepest underground science lab at a depth equivalent to more than six Empire State buildings — a place uniquely suited to scientists’ quest for mysterious particles known as dark matter.

Scientists, politicians and other officials gathered Monday for a groundbreaking of sorts at a lab 4,850 foot below the surface of an old gold mine that was once the site of Nobel Prize-winning physics research.

The site is ideal for experiments because its location is largely shielded from cosmic rays that could interfere with efforts to prove the existence of dark matter, which is thought to make up nearly a quarter of the mass of the universe.

Read complete article here. {via Associated Press}

Dark matter ring. (Credit: Image courtesy of Andalucía Innova)

Here’s an article on the ever elusive dark matter. Science seems to be making some sort of headway on this stuff.

ScienceDaily (June 9, 2009) — Dark matter is an enigmatic energy that makes up most of the mass in the Universe, whose nature has not yet been identified. Researchers have succeeded in estimating the percentage of dark matter in the Universe and describing the processes related to the very existence of this matter. But, until now, no one has established the distribution and behavior of the dark matter in a galaxy.

Now, astronomers in the Theoretical Physics and Cosmos Department of the University of Granada, led by Eduardo Battaner, in collaboration with researchers in the Applied Mathematics Department, have made great progress: establishing the distribution and behaviour of the dark matter in a galaxy.

New mathematical calculations on the dark matter describe the density profiles which define how the dark matter changes in a galaxy. This had not been specified in the astronomy field yet. Until now, the behaviour of the dark matter had been estimated through simulations, but the new mathematical description approach based on equations and functions which describe each characteristic of the dark matter make this result much more reliable.

Read complete article here. {via ScienceDaily}