Posted on 01/03/2003 6:35:40 AM PST by forsnax5
HANOVER, NH - A Dartmouth researcher is building a case for a "dark energy"-dominated universe. Dark energy, the mysterious energy with unusual anti-gravitational properties, has been the subject of great debate among cosmologists.
Brian Chaboyer, Assistant Professor of Physics and Astronomy at Dartmouth, with his collaborator Lawrence Krauss, Professor of Physics and Astronomy at Case Western Reserve University, have reported their finding in the January 3, 2003, issue of Science. Combining their calculations of the ages of the oldest stars with measurements of the expansion rate and geometry of the universe lead them to conclude that dark energy dominates the energy density of the universe.
“This finding provides strong support for a universe which is dominated by a kind of energy we’ve never directly observed,” says Chaboyer. “Observations of distant supernova have suggested for a few years that dark energy dominates the universe, and our finding provides independent evidence that the universe is dominated by this type of energy we do not understand.”
The researchers came to this conclusion as they were refining their calculations for the age of globular clusters, which are groups of about 100,000 or more stars found in the outskirts of the Milky Way, our galaxy. Because this age (about 12 billion years old) is inconsistent with the expansion age for a flat universe (only about 9 billion years old), Krauss and Chaboyer came to the conclusion that the universe is expanding more quickly now than it did in the past.
The only explanation, according to Chaboyer and Krauss, for an accelerating universe is that the energy content of a vacuum is non-zero with a negative pressure, in other words, dark energy. This negative pressure of the vacuum grows in importance as the universe expands and causes the expansion to accelerate.
ET PHONE HOME, DADDY WANTS YOU
[This ping list for the evolution -- not creationism -- side of evolution threads, and sometimes for other science topics. To be included, or dropped, let me know via freepmail.]
Black Crunch jams Universal cycle [Cosmology].
Scientists Seek 'Dark Energy' That's Filling In the Universe.
Cosmic Microwave Background Radiation's Polarization Detected at Last.
Thanks for the ping.
I'm still trying to comprehend the above statement. I should have taken more math.
The only explanation, according to Chaboyer and Krauss, for an accelerating universe is that the energy content of a vacuum is non-zero with a negative pressure, in other words, dark energy. This negative pressure of the vacuum grows in importance as the universe expands and causes the expansion to accelerate.It has an eerily Barry-Setterfieldian "more energy is periodically pumped into the universe from the vacuum, thus violating conservation of energy" kind of ring. I hate it when the loonies get something to lawyer with.
This sounds like what most of the crevo threads devolve into...
I donno. More energy is actually more matter/energy, which automatically means more gravity. And if gravity has a minus sign (as it must to cancel out matter/energy and result in a net zero for the universe), then this new dark energy stuff must be generating more gravity, which automatically cancels it out and we'd still have a net energy component of zero for the universe. Makes sense? We need Physicist to come to our aid.
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