January 18
Adam Riess (Johns
Hopkins & STSCI)
Supernovae and the Discovery of the Accelerating
Universe
In
1929 Edwin Hubble discovered that our Universe is expanding. Eighty years
later, the Space Telescope which bears his name is being
used to study an even more surprising phenomenon, that the expansion is
speeding up. The origin of this
effect is not known, but is broadly attributed to a type of "dark
energy" first posited to exist by Albert Einstein and now dominating the
mass-energy budget of the Universe. I will describe how our team discovered
the acceleration of the Universe and why understanding the nature of dark
energy presents one of the greatest remaining challenges in astrophysics and
cosmology.