October 11, 1999
Noted astronomer to deliver the first public lecture of a new astronomy series
By Tim Stephens
Recent observations of very distant exploding stars have provided evidence that the
expansion of the universe is speeding up with time rather than slowing down as cosmologists
had expected. These observations, called the Science Breakthrough of 1998 by Science
magazine, revived the idea of a long-range "anti-gravity" effect in the
universe.
UC Berkeley astronomer Alex Filippenko, a prominent member of an international team
that first reported these striking findings, will discuss their implications on Tuesday,
October 26, in a public lecture at UCSC. His talk, "Einstein's Biggest Blunder?
The Case for Cosmic 'Anti-gravity,'" will begin at 8 p.m. in Classroom Unit
2. Admission is free.
Albert Einstein introduced the idea of a "cosmological constant," a long-range
repulsive effect in the universe, because he believed the universe to be static and
recognized that gravity should make it contract. When Edwin Hubble discovered that
the universe is actually expanding, Einstein renounced the cosmological constant,
calling it the biggest blunder of his career. Ever since, cosmologists have assumed
that the universe began in an expanding state (the Big Bang) and that gravity has
gradually slowed down this expansion.
Now, however, Filippenko's group and another independent team of researchers have
found strong evidence that the expansion of the universe is actually accelerating
with time. They based this startling conclusion on observations of very distant supernovae,
exploding stars that shine very brightly and can be used as beacons for measuring
great distances in the universe. In order to explain these findings, cosmologists
have revived Einstein's cosmological constant, a positive force countering the effect
of gravity and propelling the continued expansion of the universe.
The implications are that the universe will expand forever and that space is geometrically
flat on large scales. The age of the universe derived from this model is 14 billion
years, consistent with the ages of the oldest known stars.
In his talk, Filippenko will present an overview of this research and discuss its
implications. Filippenko's research accomplishments have been recognized by several
major awards, including the American Astronomical Society's Pierce Prize and the
Canadian Astronomical Society's Petrie Prize.
A dedicated and enthusiastic instructor, he has won the top teaching awards at
UC Berkeley, and in 1995 was voted the "Best Professor" on campus in an
informal student poll. Recently, he produced a 40-lecture video course on introductory
astronomy with The Teaching Company.
Filippenko's talk is the first of the Halliday Lectures, a new series of public lectures
presented by UCSC's Department of Astronomy and Astrophysics. The lecture series
is supported by a gift from John and Layne Halliday. John Halliday is a trustee and
former president of the UC Santa Cruz Foundation.
Parking is available in the lot at Hahn Student Services, down the hill from Classroom
Unit 2, or at the East Field House. For more information, please call the UCSC Public
Information Office at (831) 459-2495.
