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Physicists currently believe that most of the dark matter in the universe is made up of individual particles, and the challenge is to work out what kind of particles these are. New research, however, overturns this assumption and says that observational and experimental data are better explained if dark matter exists as composite particles - atoms of dark protons and dark electrons that are acted on by the dark-matter equivalent of the electromagnetic force.

As someone who's researched dark matter extensively, it is my determination that dark matter most likely exists, although explaining exactly what it is is a challenge. Over this next series, I would like to lead you through the evidence, observations and discoveries that have led me to this conclusion, and I hope that I explain this well enough that it leads you to draw the same ones for yourself.

For several decades, astronomers and cosmologists have been piling up data that indicates most of the matter in the Universe is dark, interacting only via gravity. As modified theories of gravity failed to account for observation, candidates for dark mater were winnowed down until one remained in favor: the weakly interactive massive particle, or WIMP. Over the past several years, potential signals of WIMPs have appeared in space and on Earth; that, combined with the startup of the LHC, has given the research community the sense that it's close to pinning down the identity of the WIMPs. But a review in this week's Nature considers what might happen if we fail.

We got the same measurement no matter which method we used, finding out that 25-30% of the total energy of the Universe is in some type of matter. But, only about 0.5% of the total energy is in stars, which means that nearly all of this matter doesn't give off light! So what is the rest of this matter?

The paper, Gentile et al, Nature, 461, 627, 2009, discusses the apparent constant surface mass density of disk galaxies in the centers, over several orders of magnitude in mass and luminosity of galaxies, and that the density, when fit with a cold dark matter inspired density profile for the galaxy halos, leads one to conclude the break radius is such that the inferred cold dark matter density decreases at a radius corresponding to an apparently near constant acceleration.

In addition to sensing distant galaxies made entirely of antimatter, the AMS will also test leading theories of dark matter, an invisible and mysterious substance that comprises 83 percent of the matter in the universe. And it will search for strangelets, a theoretical form of matter that's ultra-massive because it contains so-called strange quarks

Good article, though it still doesn't identify dark matter. Could it be the neutralino? Wait the results from the LHC in 2010 with great interest.

New experiments have revealed tantalizing evidence that sterile neutrinos are not only real but common. Some of them could even be the stuff of the mysterious dark matter astronomers have puzzled over for decades.

Together with ever-improving observations of the early universe, grand simulations are beginning to paint a single, unifying picture of why the universe looks as it does. At its heart is an almost invisible scaffold of dark matter and cold gas on which the visible constituents of the universe hang - a structure known as the cosmic web.

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The ATLAS detector is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy. ATLAS will learn about the basic forces that have shaped our Universe since the beginning of time and that will determine its fate. Among the possible unknowns are the origin of mass, extra dimensions of space, unification of fundamental forces, and evidence for dark matter candidates in the Universe.

The predicted neutralino may actually make up a portion or all of dark matter, if it's existence can be proved by the LHC.