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Old 10-November-2003, 12:17 AM
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Normandy6644 Normandy6644 is offline
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Default Article in WIRED magazine...

Yes, I understand that WIRED magazine is not exactly a prestigious scientific joournal, but my dad did find an article in it that puzzle him. he gave it to me to see if I could make any sense of it. The article in its entirety can be found here. Here are some snippits:

Quote:
Since the days of Galileo's telescope, new and better scientific instruments have steadily transformed our conception of the universe. Now we've got the Wilkinson Microwave Anisotropy Probe. This superb gizmo, launched in June 2001, is floating 1 million miles from Earth in the second Lagrange Point, measuring the density of the universe with unheard-of digital accuracy and sending data back to mission control.

Already, the probe's findings have provided a few salient new notions about the nature of cosmic reality. For starters, the universe is 13.7 billion years old. Unlike previous figures, this is not a rough estimate; the margin of error is about 1 percent. In addition, the universe is flat. Forget all that mind-boggling space-time-is-curved stuff. Euclid was right all along. And the space-time pancake will expand infinitely. There's no such thing as an end to this particular universe.
Ok, most of that just seems wrong to me, especially the part about flat spacetime. But let's continue....

Quote:
It gets worse. Dark matter, the 23 percent formerly thought to be burnt-out stars and lonely little planetoids, probably has nothing to do with normal, so-called baryonic matter. It might be axions and neutralinos, leftover twiddly bits predicted by string theory. Or it might be what physicists call weakly interactive massive particles, or WIMPs, which form a kind of cosmic smog that builds up in the wake of nuclear interactions.
It seems to me that he is using theoretical predictions to support his argument. [-X

It goes on like this, essentially saying that all of today's cosmology is wrong, but without citing any sources. Has anyone else seen this and care to comment? if not, it's a rather short article, go ahead and check it out.
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Old 10-November-2003, 02:36 AM
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After doing a search on the author, it appears he has a degree in journalism and has written plenty of science fiction. Perhaps he just misinterpreted certain information?
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Old 10-November-2003, 10:22 PM
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He is confused about flat geometry, that's for sure.

Spacetime is curved locally by mass, in the same way that a heavy rock distorts a mattress.

But that's different than overall geometry, the curving of spacetime as a whole. That's a universal property, not a local one.

Hmph, it would take longer than I have to describe how spacetime geometry works (using parallel lines, for example). Anyone wanna have a go at this?
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Old 11-November-2003, 12:09 AM
Ian Goddard Ian Goddard is offline
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I saw Max Tegmark speak last week on the recent SDSS data. The best evidence continues to suggest that spacetime is flat, or nearly flat, overall. In fact Tegmark said spacetime may be perfectly flat, but the data is not yet clear enough to say for sure. As Phil notes, that's not a comment on local spacetime topographies. Indeed, as Max pointed out, the SDSS data
interpretation rests on the assumption that General Relativity is true.

Inflation models of the universe predict that spacetime is flat. This is an important feature of inflation theory since if spacetime is flat, then total energy equals zero -- the negative energy of the gravitational field exactly cancels the positive energy of mass. This could explain how a universe could spring forth from nothing without violating the conservation of energy. So "nothing ((+) + (-)) from nothing" may leave universe.
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Old 12-November-2003, 02:05 AM
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Quote:
Originally Posted by The Bad Astronomer
He is confused about flat geometry, that's for sure.

Spacetime is curved locally by mass, in the same way that a heavy rock distorts a mattress.

But that's different than overall geometry, the curving of spacetime as a whole. That's a universal property, not a local one.

Hmph, it would take longer than I have to describe how spacetime geometry works (using parallel lines, for example). Anyone wanna have a go at this?
Yeah I know the basics of this. But what evidence is there that spacetime, even as a whole, is flat?
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Old 12-November-2003, 11:01 PM
Ian Goddard Ian Goddard is offline
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Quote:
Originally Posted by Normandy6644
[...] what evidence is there that spacetime, even as a whole, is flat?
The evidence that suggests the universe is flat (ie, that spacetime is Euclidean) is the measurement of "ripples" in the cosmic microwave background radiation. "If the universe is flat, the largest undulations would appear to be about one degree across [...] Ground and balloon-borne observations suggest that the ripples are one degree across" (Krauss). Since then COBE, WMAP, and SDSS have not only corroborated those findings, but tightened up the parameters.

Perfect flatness corresponds to a spectral index of 1 (Omega = 1) as seen in this graphic. The area in white is the region of possibility, all colored regions are ruled out by the WMAP and SDSS data. The possible region is considered to be "nearly flat." The data should continue to tighten up over time, but at this time essentially all the data on the question of universal geometry indicates nearly flat spacetime.

See Max Tegmark's SDSS page, he's one of the leading scientists working on this issue. The graphic I just discussed is the second on that page.

Krauss, Lawrence. "Cosmological Antigravity." Reprinted in Scientific American (Special Edition, "The Once and Future Cosmos"), Dec 31, 2002. 31-39.
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Old 14-November-2003, 04:52 AM
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Could someone explain what you mean by flat?
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Old 14-November-2003, 08:46 PM
Ian Goddard Ian Goddard is offline
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Quote:
Originally Posted by Kebsis
Could someone explain what you mean by flat?
Here's a good description: Spatial Curvature.
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Old 14-November-2003, 10:40 PM
Ian Goddard Ian Goddard is offline
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Check it out, Professor Wright whose Spatial Curvature page I just linked to has several pages debunking bad cosmology: Cosmological Fads and Fallacies
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