Wednesday, January 4, 2012
What the #*!$ is dark matter? One astrophysicist's perspective
Annika Peter, UC Irvine
The nature of dark matter is one of the major "known unknowns" of physics of the Universe. From astronomical observations, we know that dark matter exists, makes up 23% of the mass budget of the Universe, clusters strongly to form the load-bearing frame of structure for galaxy formation, and hardly interacts with ordinary matter. This information is not enough to identify the particle specie(s) that make up dark matter, though. As such, the problem of determining the identity of dark matter has largely shifted from astronomy to the fields of astroparticle and particle physics. In this talk, I will give an overview of the ecosystem of astroparticle and particle-physics searches for dark matter, and show what its prospects are for dark-matter detection in the next decade. I will also highlight some of the pitfalls of this particle-physics-oriented search. This will lead me to advocate a return of the problem of dark-matter identification to astronomy, and show what kinds of theoretical and observational work might be used to pin down the nature of dark matter once and for all.