'New ocean of discovery'
Michael S. Turner
Professor, Departments of Astronomy and Astrophysics, and Physics, and the College; Enrico Fermi Institute; Kavli Institute for Cosmological Physics
Education: Ph.D., Stanford, 1978
Location: AAC 140A
WWW: Web Site
Theoretical astrophysics, cosmology and elementary particle physics, cosmology
My research focuses on the application of modern ideas in elementary-particle theory to cosmology and astrophysics. I believe that this approach holds the key to answering the most pressing questions in cosmology.
Research Fields: Cosmology
Graduate: Chaz Shapiro (2008)
Office: 329 Natural Sciences II
Electronic mail address: email@example.com
Office phone: (831) 459-3033
Fax: (831) 459-3043
Although physicists have yet to say what dark energy is, they have some ideas about where it came from. Some say it could percolate from the vacuum of space. Laboratory experiments show that seemingly empty space is actually seething with virtual particles that wink in and out of existence.
This perpetually bubbling vacuum provides energy that could take the form of a repulsive "negative gravity," some say. The problem is that this vacuum-energy as calculated would be so absurdly powerful that it would have blown apart the universe very long ago. One way out is to assume that the vacuum-energy vastly weakens over time and is not constant as imagined by Einstein. This leads to another idea called "quintessence" (for "fifth essence") which proposes a repulsive field embedded in space, not unlike a gravitational field or a magnetic field.
Under that hypothesis, the field was created in the early moments of the universe along with the other forces in nature, and now stretches across the universe like a spider web. As the universe expanded and cooled, gravity and quintessence were locked in an arm wrestle for dominance over space. Both fields weakened with the universes expansion. But ultimately quintessence won out over gravity and took control to push galaxies apart.
Astronomers plan to look at more distant supernovae to precisely track how the universes expansion rate has changed, and this hopefully will narrow the dark energy alternatives.
Arip Nurahman (Teacher and Professional Lecturer)