November 17, 2009
Only 4% of the Universe is made of the ordinary atomic matter that constitutes the objects in our daily experience as well as ourselves. The majority of the Universe resides in the Dark Side: Dark Matter and Dark Energy. This talk will examine the dark matter that comprises 95% of the mass of the Milky Way and all other galaxies. I will begin by reviewing the observational evidence for dark matter including rotation curves of galaxies. Then, I will discuss proposed candidates for the dark matter, which is probably made of some new kind of fundamental particle. The best motivated dark matter particles are Weakly Interacting Massive Particles, or WIMPs, such as supersymmetric particles or particles from extra dimensions. A great deal of excitement currently pervades this field because of current and upcoming experiments that can find the dark matter, via both direct and indirect techniques. We first made these predictions twenty years ago, and it is very exciting that more and more unexplained signals are emerging that may in fact be signatures of dark matter detection. These particles have been powerful motivation for the LHC at CERN, the underground experiments such as XENON, satellites such as FERMI or PAMELA, and neutrino detectors such as ICECUBE at the South Pole. The current status will be discussed. In the remainder of the talk, I will also discuss Dark Stars: the first stars to form in the universe may be powered by WIMP dark matter heating rather than by fusion (a new phase of stellar evolution) and may be detectable as well..
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Colloquia are held Tuesdays in Room 1410 at 4:00 pm (preceded by light refreshments at 3:30). If you have additional questions, please call 301-405-5946.