Tuesday, June 03, 2008

Dark, Perhaps Forever?

The New York Times has a lengthy piece on the current effort in the study of Dark Energy.

A decade ago, astronomers discovered that what is true for your car keys is not true for the galaxies. Having been impelled apart by the force of the Big Bang, the galaxies, in defiance of cosmic gravity, are picking up speed on a dash toward eternity. If they were keys, they would be shooting for the ceiling.

“That is how shocking this was,” Dr. Livio said.

But what I just don't quite understand is this kind of reaction:

It is still shocking. Although cosmologists have adopted a cute name, dark energy, for whatever is driving this apparently antigravitational behavior on the part of the universe, nobody claims to understand why it is happening, or its implications for the future of the universe and of the life within it, despite thousands of learned papers, scores of conferences and millions of dollars’ worth of telescope time. It has led some cosmologists to the verge of abandoning their fondest dream: a theory that can account for the universe and everything about it in a single breath.

Forget about the fact that I don't quite believe that such a thing is possible (i.e. "account for the universe and everything about it in a single breath") due to my view that the "TOE" is a fallacy. But why are they giving up so quickly? I mean, the discovery of dark energy has only been about 10 years old! This is a blink of an eye! Condensed matter physicists had dealt with the mysteries of high-Tc superconductors for 20 years already, and you don't hear them giving up! And they have more data and more discoveries to content with.

If the Dark Energy Survey really gets off the ground, there's a good chance that more evidence on the nature of dark energy will be revealed. Aren't people just salivating for that kind of information? I don't know what is there to be discouraged about. If I were in this field, I'd say that this might be some of the most exciting time to be alive!



Anonymous said...

Now I'm no physicist, Not by a long shot, I dont mean to sound naive, But isnt this dark energy you speak of just a form of entropy? I'd really like to know if anyone can clear things up for me..I'm very, VERY bored....

Chaz said...

I agree ... it's incredibly premature to be abandoning all hope, but the concern that dark energy will remain mysterious forever is somewhat justified. Right now, the only handle we have on dark energy is the way that it affects the geometry of the Universe. You can also keep testing General Relativity to look for deviations that might help explain cosmic acceleration without dark energy. But ultimately there are lots of dark energy models that can be rigged to match the small number of available observations. So it's possible that surveys like DES won't provide a satisfying amount of information on dark energy. Of course, there's only one way to find out! Anyway, such surveys are filled with other interesting information about cosmology and are bound to lead to breakthroughs.

Kent Leung said...

Come on! I thought the article was being overly pessimistic for dramatic effects. I didn't know people really felt that way! Nothing remains mysterious forever since forever does not exist. This is the biggest problem in physics today, which as ZapperZ pointed out has only existed for 10 years. We have only really started to understand its true nature in the last 5 years thanks to remarkable CMB data from WMAP.

I feel to get to the heart of the matter we must first get a grasp on dark matter and fill the gaping holes in the Standard Model. We are on the verge of doing just that with LHC coming online. Last week, I was at an international workshop with cold neutrons and measurements of the neutron EDM is on the verge of getting to the limits of closing in on new physics in CP violation. I feel we are coming pretty close to redefining a new Standard Model which will now tie closely with astrophysics.

Although understanding the creation and evolution of the universe is a very difficult task, I still bet my hat that we will get there if not in this century, certainly the next. That is assuming we don't kill ourselves before then.

Anonymous said...

Please, please resist the apparantly overwhelming temptation to fall prey to the misleading mindset that underlies such phraseology as '...since the _discovery_ of dark matter...'. Dark matter was not discovered ten years ago, nor nine, neither eight through one, nor yet this year. It was invented ten years ago, and has been memetically rewiring the epistomological credulity of physicists and lay-people alike with great furor during its brief -- and conjectural -- existence. The discovery of dark matter, should the nature of reality correspond so fortuituously to wish-fulfillment as do dreams and fantasy, would entail the repeatable, phenomenological demonstration of mass interactions involving substances without strong electromagnetic coupling. Throughout the history of science, whenever the predictions provided by provisional and contingent theories of nature have failed to reconcile with observed behaviour, the wise have opted to act in ontological economy and revise the theories to correspond with the observations. It is only in our most recent folly that this epistomological thrift has been thrown to the wind, and -- for the sake of theoretical turpor and surfeit of imagination -- we have resorted to the hubris of cosmological fiat. "Let there be matter!", the physicist declared. And he saw that (if it was conveniently located in exactly the right, undetectable, configuration) it was good. And evening came and mourning came on the sixth night.

ZapperZ said...

First of all, it was "dark ENERGY" that was "discovered" 10 years ago, not dark matter. Dark matter, or at least the effect of it, was observed WAY before dark energy.

So before you put your foot in your mouth, get your FACTS straight.

And they could have called it by some exotic names if they wish, and you'd be none the wiser, because it seems that all you care about is why it is called that, rather than the PHYSICS of it. Do you care that a gap that opened above Tc in the underdoped cuprates is called a "pseudogap", or that an effect that we don't quite expected can be called a "anomalous quantum hall effect"? How come I don't hear you bitching about those?

The physics that arises out of Dark Matter is VERY clear. The physics from Dark Energy is still very much being studied, and that's why they had just launched GLAST, and why the Dark Energy Survey project is one of the highest priority in the Astrophysics funding. It means that we still need to know more about these unexpected observation!

Oy vey!