Posted on 03/16/2006 11:31:54 AM PST by The_Victor
Physicists announced Thursday that they now have the smoking gun that shows the universe went through extremely rapid expansion in the moments after the big bang, growing from the size of a marble to a volume larger than all of observable space in less than a trillion-trillionth of a second.
The discovery — which involves an analysis of variations in the brightness of microwave radiation — is the first direct evidence to support the two-decade-old theory that the universe went through what is called inflation.
It also helps explain how matter eventually clumped together into planets, stars and galaxies in a universe that began as a remarkably smooth, superhot soup.
"It's giving us our first clues about how inflation took place," said Michael Turner, assistant director for mathematics and physical sciences at the National Science Foundation. "This is absolutely amazing."
Brian Greene, a Columbia University physicist, said: "The observations are spectacular and the conclusions are stunning."
Researchers found the evidence for inflation by looking at a faint glow that permeates the universe. That glow, known as the cosmic microwave background, was produced when the universe was about 300,000 years old — long after inflation had done its work.
But just as a fossil tells a paleontologist about long-extinct life, the pattern of light in the cosmic microwave background offers clues about what came before it. Of specific interest to physicists are subtle brightness variations that give images of the microwave background a lumpy appearance.
Physicists presented new measurements of those variations during a news conference at Princeton University. The measurements were made by a spaceborne instrument called the Wilkinson Microwave Anistropy Probe, or WMAP, launched by NASA in 2001.
Earlier studies of WMAP data have determined that the universe is 13.7 billion years old, give or take a few hundred thousand years. WMAP also measured variations in the cosmic microwave background so huge that they stretch across the entire sky. Those earlier observations are strong indicators of inflation, but no smoking gun, said Turner, who was not involved in the research.
The new analysis looked at variations in the microwave background over smaller patches of sky — only billions of light-years across, instead of hundreds of billions.
Without inflation, the brightness variations over small patches of the sky would be the same as those observed over larger areas of the heavens. But the researchers found considerable differences in the brightness variations.
"The data favors inflation," said Charles Bennett, a Johns Hopkins University physicist who announced the discovery. He was joined by two Princeton colleagues, Lyman Page and David Spergel, who also contributed to the research.
Bennett added: "It amazes me that we can say anything at all about what transpired in the first trillionth of a second of the universe."
The physicists said small lumps in the microwave background began during inflation. Those lumps eventually coalesced into stars, galaxies and planets.
The measurements are scheduled to be published in a future issue of the Astrophysical Journal.
You know the experiment, but it is not about heat, but rather a demonstration that light has momentum (and therefor mass). One side of the vanes is black to absorb photons, and the other is silver to reflect them. Shine a light on it and the device spins. I can't find one online though. I remember seeing them in the ads in the back of "Boy's Life."
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Why turtles?.. Why NOT Moonbats..?
The photons have a momentum, not a mass.
Anyway, the windmill/lightbulb doesn't really have much to do with photon momentum, it has more to do with differences in temperature on the vanes and the gas molecules inside the bulb.
I suppose it is theorized that C did not get established as a property of radiant energy until after this "expansion" business.
Is this the first you've heard of the expansion of the universe? It does not conflict with relativity. Relativity at first predicted it, although Einstein was unnerved enough to find a way to revise that feature out. The universe has some finite volume (although incredibly huge, far far bigger than the part we can see) but no edge or surface. Within it, everything is still relative to the observer's frame of reference. Outside of it... who knows?
"Stretching across the entire sky" is not properly descriptive of a "hugeness" of variations - indeed, a constant microwave background could also "stretch across the entire sky". So, I'm still wondering what, exactly, the author was trying to convey with that strange wording...
Yes,....
well, sort of.
Light has momentum. The photons have no rest mass, but since they move at the speed of light and from all relative observers, always move at that speed, the photos have a measurable mass associated with it's high velocity. Do a Google search on "light, momentum, photon, mass" and you'll turn up a ton of good explanations.
One problem remains with the inflation theory. In order for the universe to expand that rapidly, the matter that existed in the first instance of the universe would have to travel MUCH faster than the speed of light.
I question the introduction of the term "sky" in the whole thing. I'll have to read this later, after several sips of a good single malt..
No. The space is expanding. The mass is just staying put within the space.
But in order to have momentum, mass is required. Photons have no rest mass, but since they are never at rest, they have a measurable mass, even if that mass is purely associated with it's velocity.
"Why turtles?.. Why NOT Moonbats..?
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It's a Hindu thing. You wouldn't understand.
The bulb is supposed to be pumped down to a vacuum.
"No. The space is expanding. The mass is just staying put within the space."
I don't think this is going to get across. The concepts are just a little too difficult for most folks to grasp, I'm afraid.
The concept of space isn't something that most people understand, and it's hard to explain, since it requires stepping away from observable reality.
Doesn't that violate the law that nothing can travel faster than the speed of light?
Nope, things aren't allowed to move through spacetime faster than the speed of light, but spacetime can stretch and carry stuff with it that fast.
The balloon analogy was what worked for me.
Nope, it's not the first I've heard of the expansion of the universe.
I remember the epicycles and geometrics of a past age too.
It's pretty clear to me that we're in one of those "epicycle phases" of our knowledge, where what we're seeing is odd and doesn't work very well with something else we think, but all we've got is the model so we have to soldier on until someone has a brilliant insight that makes the thing simpler and rational.
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