Posted on 01/30/2008 4:57:20 PM PST by decimon
PARIS (AFP) - Astrophysicists believe they are closing in on one of the cosmos' great mysteries: why the expansion of the Universe, triggered by the Big Bang, is accelerating.
The answer could be tantalisingly within reach, according to their study, released on Wednesday by the British weekly science journal Nature.
A decade ago, astronomers were stunned to learn that the Universe was expanding more quickly than in the past.
It had long been assumed that the mutual attraction of galaxies through gravity would slow the expansion of space, kicked off by the Big Bang some 14 billion years ago.
Two very different theories have emerged to explain this shock discovery.
One is that the Universe is filled with so-called dark energy, a substance that has been inferred but never seen. Dark energy cannot be detected with present technology as it neither emits nor reflects light or radiation.
Dark energy, so the theory goes, counteracts the gravitational attraction that galaxies exert on each other and which would otherwise brake the cosmic expansion.
The other possible explanation is that dark energy does not exist.
If this were true, current theories about gravitational force as the prime mover in the Universe would be flawed -- they would only make sense if there are additional dimensions to space.
Until now, observations have not strongly supported either scenario.
But a new approach may unlock the enigma, say the paper's authors.
Using the European Space Agency's (ESO) Very Large Telescopes (VLS), an international team of 51 astronomers led by Luigi Guzzo of the Astronomico di Brera in Merate, Italy measured the distribution and movement of some 10,000 galaxies over a period of 30 years.
The goal of their observations was to assess the great forces in the cosmic tug-of-war -- the overall expansion of the Universe, which pushes galaxies away from each other, and the force of gravity, which pulls them together.
By indirectly measuring the speed at which the galaxies travelled, the scientists were able to create a 3-D map of an expanding Universe that also informs about movements within the galaxies themselves.
"Measuring this distortion at different epochs of the Universe's history is a way to test the nature of dark energy," said Oliver Le Fevre, from the Laboratoire d'Astrophysique de Marseille.
The big tool was a spectrograph -- an instrument to record X-rays -- on one of the four 8.2-metre (320-inch) ESO telescopes perched on the summit of the 2,635-metre (10,374-feet) Cerro Paranal in the Chilean Andeas.
They scanned thousands of galaxies across a patch of sky roughly 20 full moons across.
The results, while not conclusive, are consistent with a "dark energy" explanation for the acceleration of an expanding Universe, say the researchers.
The next step is to extend the observations tenfold.
"This technique should be able to tell us whether cosmic acceleration originates from a dark energy component of exotic origin, or requires a modification of the laws of gravity," said Guzzo.
According the most recent models, he said, 73 percent of cosmic energy seems to consist of "dark energy."
I gotta stop doing these quick glances through the article titles. I read this as “..cosmic enema.” Geez.
“One is that the Universe is filled with so-called dark energy, a substance that has been inferred but never seen.”
Its inferred but never seen, sounds quite worthy of a government grant or two.
It will probably turn out that the “big bang” is still going on, hence the accelleration is increasing.
I mean, it only happened yesterday...
Maybe its expanding faster because God wants it too?
I thought it was because God wanted it that way - who knew?
Maybe to keep the bad aliens away from the good ones.
There's some dark energy for ya.
“One is that the Universe is filled with so-called dark energy, a substance that has been inferred but never seen.”
perfect ‘scientific’ evidence.......
and they laff a creationists (roll eyes here...)
threads about asteroids and cosmic enigmas...
Just more of the stuff we’re never going to know before at least 100 years.
From the article it seems the European taxpayers are on the hook for observatories wherever there is a tall mountain.
Maybe the Universe didn’t begin with the Big Bang, but instead, was created by God?
Maybe all of this is nothing more than a passing thought in the mind of God.
It’s because of global warming.
I really can’t buy the theory of “dark energy”, the invisible force at work is magnetism if you ask me.
“I really can’t buy the theory of “dark energy”, the invisible force at work is magnetism if you ask m”
Dont think magnetism is effective over the long distances, I could be wrong of course.
Magnetism as opposed to gravity? What would generate the magnetism?
Not trying to give you a hard time with that as I don't have a clue.
Scotty, you get this right or your next job will be a bouncer in a Klingon cathouse.
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