I’ve been pleased to read about the recent results from the detector on the ISS called AMS and an underground detector down a mine in Minnesota, called CDMS, which *hint* at ideas about dark matter. Hint is pretty crucial: weakly interacting massive particles (WIMPS) are extremely hard to detect, the AMS detector result is a detection of an excess of high-energy positrons, supposedly the result of WIMP annihilation in our galactic centre. But can we be sure it means this, above the background signals from other cosmic processes? Not really, calling it a signature of dark matter is hype, says Jester.
Then there’s the CDMS results posted on the physics Arxiv server here on Monday. These were analysis of data collected in 2006-2007, in which 3 particle events could have been a detection of dark matter itself hitting they crystal and making it recoil. Making sense of the results depends on the dark matter models you have, however, and these results seem to favour a more complex sort of model where you have different types of WIMP, some of which may interact – perhaps by a dark force?
It seems there’s a long way to go before we can describe dark matter reliably, all we know is that it seems to account for about 80 per cent of the Universe’s mass, revealing itself through the way stars and galaxies move due to its mass, and hence gravitational pull on them. A new satellite called Gaia is due to launch in October, which could help matters. 🙂
sophiehebden 