Spotted on P.P.Cook's Tangent Space (via Uncertain Principles): A link to a BBC News article entitled "Dark matter comes out of the cold". Apparently a team of Astronomers at Cambridge's Insitute of Astronomy have reported on a set of observations of 12 dwarf galaxies in our local cluster which apparently tell us a wealth of new information about Dark Matter and its properties. In particular, they claim to be able to put a lower limit on the effective temperature (average speed) of the dark matter particles, and.... it is not cold, but warm! If true (I suspect that it is still preliminary...I don't think there's a paper yet), it will be very interesting to see how it fits with everything else we've come to expect from other studies of dark matter (currently expected to be most likely cold), including, for example, the rather intricate simulation work that various groups do (see e.g. a post I did here), including work by our very own Risa (see links to various talks here, and more information here). So does the new data make it too hot? Or just right? Inquiring blonde girls (and bears) want to know. One to watch.... -cvj
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