Institute for Advanced Study Informal Astrophysics Seminar - NOTE LOCATION!

Observations of high-redshift 21cm brightness temperature fluctuations are challenging but can potentially provide unprecedented information about the early universe. In particular, they are the only direct probe of large-scale structure during the cosmic "dark ages", which follow the last scattering of CMB photons and precede the formation of the first luminous objects. During that epoch, the growth of overdensities is very well described by linear perturbation theory and the power spectrum of 21cm fluctuations can in principle be predicted exactly.