Dark Matter

Dark matter mystery grows
Associated Press
NEW YORK ” The Hubble Space Telescope has shown a mysterious form of energy first conceived by Albert Einstein, then rejected by the famous physicist as his “greatest blunder,” appears to have been fuelling the expansion of the universe for most of its history.
This so-called “dark energy” has been pushing the universe outward for at least nine 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 their light took more than one-half the history of the universe to reach the orbiting telescope. That means the supernovae existed when the universe was less than one-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,” Dr. 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 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 supernovae explosions to gauge the expansion of the universe made a shocking observation. It appeared that older supernovae, whose light had travelled 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 U.S. 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 the whole thing is caused by some hitherto undiscovered wrinkle in the laws of gravity.

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Everybody is entitled to my opinion.

sounds like what Maimonedes talked about in Genesis, that darkness referred initially to a primordial substance

quote:

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23 supernovae ” exploding white dwarf stars

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This is, I'm resonable certain, wrong. They would not be white dwarves.

Hi Ned, yes they will be. It's the type 1a S/N that is the standard 'standard candle', and these are WDs exploding after accreting matter from a typically massive partner in very close orbit with the WD. The more commonly explained S/N is the type II (and Ib, Ic) which is the collapse of the giant star having falied in Hydrostatic Eqm.

Thanks for that. I guess I thought the term "Super" was only applied to the biggies and ordinary "nova" to the others.

It was always thought that the Type 1a was a true biggie... the accreting matter tipped the WD over the Chandrasekhar limit and initiated collapse to a Neutron Star, with the inevitable supernova explosion. Now it seems that's not what happens, and it is much more of a HUGE nova-type mechanism. Guess I have a few text books I need to amend! The joys of a developing field...ABE - the pedant in me also should point out that we say white dwarfs, not white dwarves - for the simple and rather obvious reason that they are not of Durin's line Edited by cavediver, : Pedantry

Yes, it sounds exactly like what Maimonedes talked about in Genesis, except for two things:1) there is absolutely no reference to any "lightness' or "darkness";2) there is absolutely no reference to any "primordial substance".So, except for those two items, it does sound exactly like what Maimonedes talked about in Genesis, and once again science confirms the divine origins of the bible.

I think this is a bit misleading. For years we wondered why the Cosmological Constant appeared to be zero. Now we wonder why it is not quite zero. Not a lot has changed...

I am the layman's layman meaning that I am uniquely unqualified to comment but it sure appears to me that the more science discovers, the more we find we don't know or understand. Nothing is what we expected.I mean, is everything that exists made up of particles that have mass and/or energy but don't take up space? Personally, that wouldn't have been my first guess.I guess that in order to keep scientists in business the number of questions have to exceed the number of answers. I think you scientists will be around for a good long time yet.

There's nothing exciting about being surprised. The universe, from Planck scale to Horizon, is a big place and we should expect nothing but surprises. It's when we are not surprised - when we manage to predict the answers - that it gets really exciting. GR, QED, QCD - they're the excitement. Oh? Something unexplicable about NGC2047's rotation curve? Yeah, big deal - we didn't see that coming And particles are just an illusion - it's all in the fields...

I've seen your posts on particles being a fluctuation in a field but I've never seen you call a particle an illusion before. Is this associated with QLT?Can you expand on this at all?