Dark energy and the runaway universe
Out in the cosmos, there is really no such thing as “empty space.” Much of space is actually “dark energy” - a force that has overcome gravity and is pulling galaxies apart, expanding the universe.
Alex Filippenko, one of the world's leading astronomers, will delve into this great cosmological mystery in “Dark Energy and the Runaway Universe,” on Saturday, Nov. 7, starting at 7 p.m., at the University of Delaware's Clayton Hall Conference Center. The talk will culminate the Harcourt C. “Ace” Vernon Public Lecture Series hosted by UD's Delaware Asteroseismic Center and sponsored by the Mt. Cuba Astronomical Observatory in Greenville, Del., in honor of the International Year of Astronomy.
“Observations of very distant exploding stars (supernovae) show that the expansion of the universe is now speeding up, rather than slowing down due to gravity as expected,” says Filippenko, who is the Richard and Rhoda Goldman Distinguished Professor in the Physical Sciences at the University of California, Berkeley.
Filippenko was part of a research team that determined that the universe is expanding at an accelerating rate -- an observation that implies the existence of a mysterious, self-repelling property of space first proposed by Albert Einstein. The extraordinary finding was named Science magazine's “Breakthrough of the Year for 1998.”
“Over the largest distances, our universe seems to be dominated by a repulsive 'dark energy' -- an idea Einstein proposed in 1917, but renounced in 1929 as his 'biggest blunder,'” Filippenko says.
“Dark energy stretches the very fabric of space itself faster and faster with time. But the physical origin of dark energy is unknown, and is often considered to be the most important unsolved problem in physics; it probably provides clues to a unified quantum theory of gravity,” Filippenko notes.
An observational astronomer, Filippenko uses the Hubble Space Telescope and other observatories to study supernovae, active galaxies, black holes, gamma-ray bursts, and the expansion of the universe. A member of the National Academy of Sciences, he is one of the world's most cited astronomers, with some 600 scientific publications to his credit, as well as an award-winning textbook.
One of his major activities is to use supernovae as cosmological distance indicators, for which his group has developed the 0.76-meter Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory in San Jose. He is also interested in searching for black holes and determining the physical properties of quasars and active galaxies.
Filippenko has won the top teaching awards at UC Berkeley and has been voted the “best professor” on campus six times. In 2006, he was selected as the Carnegie/CASE National Professor of the Year among doctoral institutions.
He also has produced four astronomy video courses with The Teaching Company and appeared on numerous television programs including Stephen Hawking's Universe and The History Channel's The Universe.
An avid tennis player and hiker, Filippenko says he enjoys world travel and “is addicted” to experiencing total solar eclipses (10, and counting).
The lecture is free and open to the public. For more information see UDaily.