Something's in the air

And it might even be dark matter. There's been a rash of slightly odd and suggestive results as of late. There was the observation last month by the PAMELA satellite of an anomalous positron excess at ~50 GeV. This week the balloon-borne ATIC experiment reports seeing a bump in electrons and positrons (they can't tell the difference) at 500 GeV. MILAGRO has recently seen some weird gamma ray hotspots at 10 TeV. As if all this isn't enough, Doug Finkbeiner has been warning us that there is an unexplained CMB "haze". The reason we care about all of these observations is that they may be pointing to dark matter! Yes, dark matter is dark, so it's awfully hard to see directly. But some of the favored dark matter particle candidates happen to annihilate when they smack into each other (which happens at sufficiently high density), producing "conventional" stuff (such as ...