It came from beyond geek

One of the coolest things about cosmology - the study of the universe as a whole - is that subject of your concern is so vast and so complex that no theory, no hypothesis, is without questions and shortcomings, so there is always more to learn and discover.

It's been known and accepted for some time that the stuff we can see is only a small fraction of what there is. Even if we extend the range of our vision via technologies that can detect infrared and ultraviolet light, x-rays, and other forms of energy we can't see directly, it's still a small part. That seems startling but is actually quite reasonable: Unless something is either a source of energy (such as a star) or reflects energy (such as a planet) and that energy is intense enough when it gets here to be detected by our instruments, we can't "see" it. The existence of so-called "dark matter" is well-established, although there is still disagreement on exactly what makes it up. Is it, for example, some kind of exotic matter with which we're unfamiliar or are there just a lot of burned-out stars and "brown dwarfs" (small stars that glow so feebly they'd be almost impossible to see) out there?

The weirder notion is the existence of what's called "dark energy," a form of energy which has a major influence on the development of the universe from the "Big Bang" to now and into the future but which we can't detect, which we can only infer by its effects on matter that we can see. This still mysterious energy is a sort of anti-gravity force, one that repels rather than attracts, and that is accelerating the expansion of spacetime.

Maybe.

Marina Del Rey, California (New York Times, February 19) - Some of the biggest objects in the cosmos are behaving in a way radically out of step with the prevailing theory of how the universe was born and evolved, a team led by French astrophysicists said here on Thursday. ...

Many aspects of the universe, like its expansion rate, seem to be correctly explained by a universe in which the bright stars and glowing gases of the heavens are, in effect, floating in a sea of the unseen matter and energy. But the new findings, which rely on X-rays collected by a European satellite, XMM-Newton, suggest that the huge clusters are dancing to their own tune, refusing to behave as the mainstream theory predicts they should.

According to the theory, most of the clusters should have coalesced billions of years ago and changed only slightly since then. But by analyzing X-rays emitted by the stupendously hot gases whirling about in those clusters, the team found that there were far fewer of them in the distant past, said Dr. Alain Blanchard, a scientist at the Astrophysical Laboratory of Toulouse and Tarbes in France who spoke here.

The discrepancy with what is often called the "concordance" model, or theory, is not subtle, Dr. Blanchard said. The number of clusters several billion years ago is about a factor of 10 too small, the calculations show. Instead, he said, the clusters were still coalescing and growing in the cosmically recent past, apparently violating the predictions.

Some astronomers question the findings, noting that there are large uncertainties in the measurements made and they'd have to be confirmed before they could be accepted. Let the fun begin.

And I do mean fun.