First off, if you don’t know what dark matter is, Technology Review gives a description:
The universe is filled with mysterious invisible stuff that refuses to interact with light. It doesn’t reflect, emit or absorb light. But astronomers know it is there because of its gravitational effect on the visible stuff. They call it dark matter.
But there is a problem. If dark matter exists (and on this blog we’ve looked at a number of alternative ideas), there ought to be a lot of it out there. Astronomers estimate that 83 percent of the mass of the universe should take this form. The rest, a mere 17 percent, is visible.
So where is all this stuff? It should permeate the Solar System, the Earth and our environment. And yet when physicists look for it, they find zip.
More importantly, it seems that some scientists are coming up with consistent ways of discovering it. For more on this news, go here.