"Dark Energy" Dominates The Universe

Dartmouth College ^ | January 2, 2003 | Brian Chaboyer, Lawrence Krauss

[forsnax5]

DARK ENERGY DOMINATES THE UNIVERSE

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.

[onedoug]

I'm aware of your take locally, though clearly it seems that the density at galactic centers is gravitationally bound, almost certainly by one or more black holes which would seem to have been the seeds of galaxy formation (these must be quite old, the black holes having formed somewhat earlier in the history of the universe). And it should be gravitation which is the principle force in galactic clustering as well.

In miniature, at least, it seems to have been gravitation which grave rise to the formation of solar systems, so I'm just scaling it up.

That's certainly not to say however, that there isn't something else about which I'd scratch my head over.

What does seem quite odd though is recent observational evidence that the expansion of the universe is speeding up. If this is true, then the "dark energy" posited to account for it is very odd indeed.

As Hamlet said, "There are many things Horatio, that are not dreamt of in your philosophy." But I'm very curious and hope someday to know something ofthe "mind of God", particularly beyond this life if that's some aspsct of the way He has it figured.

[Hootch]

This is yet another result of Global Warming...

And by the way... What does cosmotology have to do with Space??

[RightWhale]

http://www.spacedaily.com/reports/XMM_Newton_Discovers_Part_Of_Missing_Matter_In_The_Universe_999.html

Paris, France (SPX) May 07, 2008

ESA’s orbiting X-ray observatory XMM-Newton has been used by a team of international astronomers to uncover part of the missing matter . . .

Only about 5% of our universe is made of normal matter as we know it, consisting of protons and neutrons, or baryons, which along with electrons, form the building blocks of ordinary matter. The rest of our universe is composed of elusive dark matter (23%) and dark energy (72%).

Small as the percentage might be, half of the ordinary baryonic matter is unaccounted for. All the stars, galaxies and gas observable in the universe account for less than a half of all the baryons that should be around. . . .

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We don’t even know half of what we know.

[woofie]

We don’t even know half of what we know.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

And we were not too sure about the first half

[woofie]

We have the dark side covered

[Bryan24]

(In my best Forrest Gump voice)

“I’m not a smart man, but I know when someone is talking out of their butt.”

I think these guys are just hoping to be called “brilliant” retroactively, by about 300 years. I don’t think they have a clue what they are talking about.

[onedoug]

We don’t even know half of what we know.

Though we do know a lot more than half of what we knew just ten years ago.