Dark matter is a (still!) hypothetical invisible substance, which accounts for the universe behaving as if it is 5 times heavier than can be accounted for by the total visible matter. There are various searches underway for dark particles, but by definition they are hard to see, barely interacting with other particles. However they must have mass, and therefore cannot be completely imperceptible. They have been dubbed WIMPS: weakly interacting massive particles.
CDMS works by detecting heat from collisions between particles passing through discs of germanium and silicon, frozen to near absolute zero. Then they have to discount the collisions by particles we already know about.
So have they found a WIMP? Or have they just narrowed down the size that any such particle may have? This would be scientifically valuable, but less spectacular.
All should become clear at 10pm GMT today, in Jodi Cooley’s webcast. (If you’re watching it and the answer doesn’t become clear, then the answer is probably the latter.)
UPDATE: there is 77% chance that they have found WIMPs!