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.
I just finished Stephen Hawkings' "A Brief History Of Time." While he keeps expressing hope that those last pieces of the "big picture" puzzle are just around the corner, you realize the physicists are juggling so many theoretical balls that they are going to crash in a jumble before anyone can pick up the pieces and make sense of it.
I was out of my depth when I was looking for my boots this morning, so I'll wait for Phys to come and decode for the laymen.
I was remarking about an unfortunate coincidence between a feature of Australian creationist Barry Setterfield's cosmology and the last sentence in this article. I say "unfortunate" knowing that the Young Earthies will take anything close for propaganda purposes. I don't think Chaboyer and Krauss are loonies, although modern cosmology for sure has a lot of real questions to answer.
Perhaps the information pressure is between non-zero and negative.
Here’s something to ponder. Feynman said ‘there is plenty of room, down.’ We exist, in conscious interaction with the universe, at a rather specific size ratio. It is as far down to the smallest manifestations of matter as it is ‘up’ to the greatest manifestations, spatially speaking. We make things to help us improve the resolution of larger and smaller, to bring it to our ratio for comprehension. Why do we not try to do the same with the temporal unresolved? The temporal resolution of our perception is extremely limited, accumulating only past, not even having present available to us, just the recent past. Not one of our devices is calibrated to adjust for better temporal resolution.
Time is a total figment. An illusion. If we were photons we would cross the entire universe instantly. Go ahead, resolve the illusion to a finer degree of instantaneous.
How ‘big’ is a photon? And you just made my earlier point (made a few years ago on one of these insane threads) that photons are a little bit of space, a little bit of time, and energy ... they cross the universe always in the present of when they were formed, so the background temporal reality they do not interact with until they ‘arrive’ at something with an ‘accumulation’ of time.
The Justice Brothers!
We are going to be sorry we ever listened to Einstein. From 1905 to now we have been thinking there are photons and that time is another spatial dimension. There are no photons, Einstein invented them, and while he didn’t make time out to be another spatial dimension he didn’t object when Minkowski did that very thing. Einstein misread Kant, as do most of us.
Now that is science for you!
If the scientific observations do not meet the preconditions, make up something that will make it sound cool and all is well again.
Bwahahahahaha
“If the scientific observations do not meet the preconditions ...” You’re stumbling over the obvious ... the preconditions are yet to be defined precisely enough. Remember that the effects of bacterial infection were pretty well understood (the preconditions) before the microscope revealed the little buggers. The effects of DNA were well observed prior to that brilliant lady revealing the molecule via x-ray photography. It was only then that Watson and Crick could fully detail the amazing ‘preconditions’ responsible for genetic evidence.
Why can't we "see" or experience the dark stuff about us?
I've got Iain Nicolson's Dark Side of the Universe : Dark Matter, Dark Energy on hold at my library, and I think I'll peruse it before stepping too deeply into this dark morass.
But I sure appreciate you two and others battting it around a bit.
Thanks.
Obama ‘s winning everything!
Um, I’ll have to say thanks but can’t accept any accolades, ‘I know nothing’. RW is the one using dark energy to heat his digs up there in cold country. LOL ... tell us your secret, RW!
We see effects that don't add up to what other things we see. For example, galaxies are difficult to model since it would take a lot more gravity to shape them than would be available from the material (stars, dust clouds, gas clouds, black holes) that appears to our < Boris Karloff voice > scientific instruments < / BKv >. So we postulate something that has gravity like the visible or nearly visible material but that is not visible and call it dark matter.
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.
This is yet another result of Global Warming...
And by the way... What does cosmotology have to do with Space??
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. . . .
We don’t even know half of what we know.
We don’t even know half of what we know.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
And we were not too sure about the first half
We have the dark side covered
(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.
Though we do know a lot more than half of what we knew just ten years ago.
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