Posted on 11/16/2006 9:07:52 PM PST by NormsRevenge
NEW YORK - The Hubble Space Telescope has shown that a mysterious form of energy first conceived by Albert Einstein, then rejected by the famous physicist as his "greatest blunder," appears to have been fueling the expansion of the universe for most of its history.
This so-called "dark energy" has been pushing the universe outward for at least 9 billion years, astronomers said Thursday.
"This is the first time we have significant, discrete data from back then," said Adam Riess, a professor of astronomy at Johns Hopkins University and researcher at NASA's Space Telescope Science Institute.
He and several colleagues used the Hubble to observe 23 supernovae — exploding white dwarf stars — so distant that their light took more than half the history of the universe to reach the orbiting telescope. That means the supernovae existed when the universe was less than half its current age of approximately 13.7 billion years.
Because the physics of supernova explosions is extremely well-known, it is possible for the astronomers to gauge not just their distance, but how fast the universe was expanding at the time they went off.
"This finding continues to validate the use of these supernovae as cosmic probes," Riess said.
He and his colleagues describe their research in a paper that is scheduled for publication in the Feb. 10 issue of Astrophysical Journal.
The idea of dark energy was first proposed by Einstein as a means of explaining how the universe could resist collapsing under the pull of gravity. But then Edwin Hubble — the astronomer for whom the NASA telescope is named — demonstrated in 1929 that the universe is expanding, not a constant size. That led to the big-bang theory, and Einstein tossed his notion on science's scrap heap.
There it languished until 1998, when astronomers who were using supernova explosions to gauge the expansion of the universe made a shocking observation. It appeared that older supernovae, whose light had traveled a greater distance across space to reach the Hubble telescope, were receding from Earth more slowly than simple big-bang theory would predict. Nearby supernovae were receding more quickly than expected. That could only be true if some mysterious force were causing the expansion of the universe to accelerate over time.
Cosmologists dubbed the force "dark energy," and ever since they've been trying to figure out what it is.
"Dark energy makes us nervous," said Sean Carroll, a theoretical physicist at the California Institute of Technology who was not involved in the supernova study. "It fits the data, but it's not what we really expected."
Answers may come once NASA upgrades the Hubble Space Telescope in a space shuttle mission scheduled for 2008. NASA and the Department of Energy are also planning to launch an orbiting observatory specifically designed to address the mystery in 2011.
Dark energy could be some property of space itself, which is what Einstein was thinking of when he proposed it. Or it could be something akin to an electromagnetic field pushing on the universe. And then there's the possibility that the whole thing is caused by some hitherto undiscovered wrinkle in the laws of gravity.
I watched a show last night about crop circles. Made me wonder.
Are there people from Cal Tech going out with architectural drawings and doing this for kicks or is there an alien culture using earth as a giant etch-o-sketch?
And, if the government just takes enough tax dollars from people who have absolutely no interest in whether or not the universe is expanding at a constant rate or not and would far rather spend the money that they earned on things that are of importance to them, then this "important" mystery might someday be solved.
More importantly PhDs in astronomy will be supported even though they cannot make a living selling their skills in a free market marketplace.
Ah a trick question.. Depends on whether a mind is a brain or a spirit?..
If a brain then a mind is a mental consruct....
If a spirit then a mind is a spiritual construct and brain is a mirror..
You have the wrong end of Mikulski. The stuff she comes out with originates at the terminal end of her digestive tract.
"Because the physics of supernova explosions is extremely well-known
Yeah, right."
That got a notice from me too. Not just known, or well known, but extremely well known.
Why not, certainly and surely, positively and undoubtedly, absolutely extremely well known.
Fascinating, Physicist! Thank you so much for the informative essay/posts.
thanks for taking the time to post that.
PING for later read.
May the Force be with you!!!
I need more coffee, this is entirely to deep on one cup!
Thanks for the ping. I am glad they are planning to service Hubble. I just hope they really do!
Ah, so it's the observation you don't like. Either you have in mind some specific flaw in the technique, or you simply don't want the universe to behave in that fashion and infer that they must have made a mistake.
I'll assume it's the former. Why won't this technique give a reliable measurement of the change in the Hubble parameter--I can't call it the "Hubble constant"--over time?
No kidding. Sigh.
In the same way, the pull of gravity should make particles fall into discrete energy levels. But because gravity is extremely weak on small scales, the effect has been impossible to spot. "To be able to measure it, you need to suppress interference from all the other fields...."
What an ingenious experiment, Physicist! Thank you so much for the link.
"article written by a scientifically illiterate journalist" placemarker
Why? Because it doesn't fit your medieval interpretation of Genesis?
I really didn't intend it to be a trick question. I'll admit it might be a koan though I'm not sure what technically makes a question a koan...so. Your answer is quite interesting however. Certainly not ordinary.
If a brain then a mind is a mental consruct....
I don't consider the brain to be mind or the generator of mind. I view mental constructs as coming from mind so I don't know if I could consider mind itself a mental construct. I can't rule that out though, my understanding is not refined enough to, but probably not. I do see brain as a mental construct.
If a spirit then a mind is a spiritual construct and brain is a mirror..
To me spirit is just understanding/awareness itself. Mind is just a reflection in the mirror and the mirror is the ground or the true nature of reality. Pure awareness beyond conceptualizations. So I would have to say that spirit is the mirror and mind is just a reflection.
I see brain as just a squishy computer that runs the body. A really really impressive computer though if just a touch glitchy and more than a tad dangerous. ; )
So, to sum that all up, I do see mind as a construct. Or put another way; a conceptual reflection of the non-conceptual reality that underlies everything. I guess that means that I haven't perfectly agreed with either of your possible views of mind so I can't pin you to either one and ask you to answer on that basis. Guess I'll just have to continue contemplatin' it on my lonesome. :^(
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