December 18, 2003

ALPHA BITS:

Science breakthrough of the year: proof of our exploding universe (Tim Radford, December 19, 2003, The Guardian)

The findings settle a number of arguments about the universe, its age, its expansion rate, and its composition, all at once. Thanks to the two studies, astronomers now believe the age of the universe is 13.7bn years, plus or minus a few hundred thousand. And its rate of expansion is a bewildering 71km per second per megaparsec. One megaparsec is an astronomical measure, totting up to 3.26m light years. Something latent in space itself is acting as a form of antigravity, exerting a push on the universe, rather than a pull.

Dark matter was proposed more than 20 years ago when it became clear that all the galaxies behaved as if they were far more massive than they seemed to be. All sorts of explanations - black holes, brown dwarfs and undetectable particles that are very different from atoms - have been suggested. None has been confirmed.

But dark matter exists, all the same. The dark energy story began in 1998 when astronomers reported that the most distant galaxies seemed to be receding far faster than calculations predicted. A study of a certain kind of supernova confirmed that they had not been misled: the universe was indeed expanding ever faster, rather than decelerating.

The discovery that some unexpected and undetectable force was pushing the fabric of space apart seemed to confirm a famous observation decades ago by the British scientist JBS Haldane: "The universe is not only queerer than we suppose. It is queerer than we can suppose." It once again raised profound questions about the nature of the universe: about space, and time, and energy, and matter. And it set the theorists on the hunt first for an explanation, and then for an experiment that would confirm their hypothesis.

So they turned once again to the original evidence for the Big Bang, the cosmic microwave background radiation. This is the original blaze of creation, cooled to minus 270 C - just about 3 C above absolute zero. Several lines of research, including experiments in the Antarctic and from high-flying balloons, began to provide a clearer picture: the universe simply had to consist of something more than just atoms and so-called dark matter.

"But WMAP, with superbly precise data beamed back from a little spacecraft a million miles away, has made the evidence more precise," said Sir Martin, of the Institute of Astronomy at Cambridge.

"The dark energy is spread uniformly through the universe, latent in empty space. Its nature is a mystery. Whereas there's a real chance of learning what the dark matter is within the next five to 10 years, I'd hold out less hope of understanding the dark energy unless or until there's a unified theory that takes us closer to the 'bedrock' of space and time."


It may just be hubris, but does any of us truly doubt that there is such a unified theory and that it is discoverable? And does not that in itself implicate the idea of Creation, regardless of your concept of Creator?

Posted by Orrin Judd at December 18, 2003 10:05 PM
Comments

My physics adviser says he is confident there is a coherent explanation that unifies quantum theory (including, someday, gravity) and relativity; and that when someone finds it, the solution will be "really simple."

If you mean, do I think the Universe behaves according to a coherent set of rules or constraints, then I think probably so.

That we'll conceive of a unified theory to mimic the set of constraints seems considerably less likely. This is not just a feeling on my part.

First, our physics as of today includes two very persuasive partial theories, neither of which, on our present understanding, is compatible with the other. So on that grounds, we're just beginners.

Second, some years ago, an author I forget tried to estimate the cosmological phenomena that we have yet to discover. (At that time, about 35 years ago, we had discovered about 130, by his count, as I recall.)

By a series of fairly straightforward arguments, he estimated about 300 more unknown phenomena, some of which seem likely to remain unknown (because of observed characters that block further observation).

I'm a skeptic about even interplanetary travel, more of a skeptic about intragalactic travel and very, very skeptical about intergalactic travel.

If the last is necessary for a unified theory, which seems at least possible, then . . .

As for creators, I'll stick with Macauley's reply to Emerson when Emerson passed on the message from Margaret Fuller, "Tell Mr. Carlyle that I accept the Universe!"

Carlyle said, "She does, does she? By God, she'd better!"

We'll have a unified theory of the cosmos before we have one of bluestockings. Of that I'm sure.

Posted by: Harry Eagar at December 19, 2003 12:30 AM

If they're there, they need to take Joe Hill's advice.

Posted by: Harry Eagar at December 19, 2003 12:33 AM

"The dark energy is spread uniformly through the universe, latent in empty space. Its nature is a mystery."

Sounds eerily reminiscent of the "aether" theory of 100+ years ago. Is anyone else bothered by the invocation of mysterious entities, having no known physical basis, to reconcile theoretical models with recent observations? Instead of dogmatically asserting their existence, isn't it at least possible that these results indicate a defect in the model used to interpret the observations?

Posted by: jd watson at December 19, 2003 12:42 AM

JD:
Invocating those entities is not dogmatic. Rather, the invocation serves as a placeholder against which to look for further verification.

Aether was just such a thing. At the time, no one could conceive of how certain phenomana could operate without some sort of transmission medium. Therefore, posit aether, and then try to determine its characteristics.

As it turns out, the most fundamental characteristic of aether is that it doesn't exist.

As with dark energy. Within our knowledge, that is the only explanation for the phenomena. Having posed it, now the search is on to define it. Two possible outcomes could be to define it right out of existence, or junk the entire model upon which the assumption is based.

That is the nature of the process, not dogma.

OJ:
a) Does truly hope and truly doubt count as a correct answer?

b) The mind boggles.

Posted by: Jeff Guinn at December 19, 2003 8:41 AM

Harry:

Interplanetary travel is child's play. (If the child is a multi-billionaire). I, and a multitude of other, could explain how it could be accomplished, and how cheap it could be, once the initial capital spending is done.

I fully expect to see such travel become unremarkable, just as traveling to Earth orbit is now worth only a five-second mention in the news, unless you're a civilian, or blow up.

Intragalactic travel seems likely, as well, although some technical problems, notably the development of some kind of hibernation or cryogenic system, remain.
The biggest problem with intragalactic travel is, it's a one way ticket to the future. Although communication between star systems will occur in real time, using quantum-linked atoms, actual physical travel could take hundreds of years, depending on destination.
Assuming, of course, that we don't develop "time warping" or "hyperspace" propulsion.

Posted by: Michael Herdegen at December 19, 2003 9:18 AM

Michael:

Harry measures the Universe by his life span alone.

Posted by: oj at December 19, 2003 10:08 AM

Jeff:

You have apparently misinterpreted my comment. It is, of course, perfectly legitimate to hypothesize entities as a basis for further investigation, but dogmatic to conclude these entities necessarily exist, as exemplified by statements like:

"The findings settle a number of arguments about the universe, its age, its expansion rate, and its composition, all at once."
"But dark matter exists, all the same."
"...the universe simply had to consist of something more than just atoms and so-called dark matter."

Posted by: jd watson at December 19, 2003 11:01 AM

JD:
You are right, I misinterpreted your comment.

Michael:
I think you are referring to the quantum mechanical effect termed "action at a distance," as truly puzzling a thing that an already beyond puzzling set of phenomena has produced.

However, I think it has been shown that it isn't possible to transmit information via action at a distance.

As far as intergalactic travel goes, absent some time warping or hyperspace device, that would be akin to paddling upstream, since nearly all galaxies are receding from us. Additionally, those same quantum mechanics will prove most troubling no matter how good your cryogenics.

DNA, among other things, isn't stable for ever.

Posted by: Jeff Guinn at December 19, 2003 2:01 PM

Sorry, the Joe Hill post was meant to go with the comments about how moderate Islamic voices seem to be increasing. Don't know how it got here.

Posted by: Harry Eagar at December 19, 2003 3:41 PM

Jeff -

Ah, but if it's a one-way trip and you have a suitable engine (fusion ramjet?), the relativistic time dialation will handle it for you; suspended animation is almost unnecessary. I think the subjective time to the other side of the universe at 1G is only a few thousand years, but would have to check the math on that.

Posted by: Mike Earl at December 19, 2003 9:42 PM
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