Einstein's Blunder Undone: The Runaway Universe

Just 100 years ago, Einstein invented a new theory of gravity called "General Relativity" and applied it to the study of the universe as a whole.  To match astronomers' understanding at the time, he introduced the Cosmological Constant, a factor that would guarantee the entire universe itself was static – neither expanding nor collapsing.  In the following decade, astronomers showed the universe was not static at all, but expanding, and Einstein banished his constant, even calling it his greatest blunder.  However, in the past 20 years, astronomers have shown that the universe is not only expanding, but speeding up.  What drives this cosmic acceleration?  We call it the Dark Energy, but it might be very similar to Einstein's idea from a century ago.  In this talk, Dr. Kirshner will show the methods used to discover the cosmic acceleration and present the evidence that we live in a Universe that is only 4% matter like the atoms of the periodic table, with the balance divided between dark energy, speeding up the universe, and equally mysterious dark matter, drawing things together.

Speaker: Robert Kirshner, Harvard University