BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Saul Perlmutter\, University of California - Berkeley\n\n
Thi s constant acted as a sort of anti-gravity to counteract the force of grav ity that would otherwise be pulling the masses of the universe together. W hen astronomers such as Hubble and others subsequently observed the red sh ifts of far distant stars and galaxies\, they discovered that the universe is not static but\, indeed\, is expanding. Therefore\, it no longer seeme d necessary to have a counter balance to gravity. It is said that Einstein \, when he heard of the expansion of the universe\, characterized his use of a cosmological constant his greatest mistake. Indeed\, for the better p art of 100 years the standard view of the universe was that its expansion rate was gradually slowing down under the influence of the gravity of its components. The question of the future of the universe was posed in terms of\, depending on the total mass of the universe\, whether the universe wo uld come to a stop and fall back in on itself\, come to a halt at infinite time\, or continue to expand forever. Professor Perlmutter and his collea gues\, using Supernovas Type Ia as &ldquo\;standard candles&rdquo\; becaus e of their great brightness\, have measured the expansion rate of the univ erse at much large distances than previously possible. In doing so\, they have made the remarkable discovery that the expansion of the universe is a ctually accelerating. There appears to be a previously undetected force of nature that acts like antigravity\, dominating the gravitational force an d causing the universe to expand faster and faster with time. So the bette r part of a century after the cosmological constant was abandoned\, it see ms that it must be re-employed to describe this new phenomenon which has b een labeled dark energy. Perhaps Einstein was right after all!
\n DTSTART:20050419T233000Z LOCATION:Chemistry Building Auditorium\, Room 402 SUMMARY:Supernovae\, Dark Energy\, and the Accelerating Universe END:VEVENT END:VCALENDAR