Thursday, February 24, 2005

Dark Matter.

This is fucking awesome.

In order to explain why the universe acts the way it does, astophysicists have been postulating the predominant existence of dark matter in the universe. Dark matter releases no radiation and is needed to make sense of why galaxies hold together, reconcile the Big Bang with existing astronomic evidence, and so on.

Dark matter is critical to theorizing what will inevitablly happen to the universe (long after we're dead). If the universe doesn't have enough critical mass, it will continue to expand forever and we'll eventually wind up in heat death, in which everything gets so far apart that communication of information and life will become impossible. I mentioned this a few days ago as part of a random rant. You can also find a somewhat fanciful story by Isaac Asimov about it here and a funny depiction of it at the ever fun Exit Mundi.

A lot of the present data points towards a Heat Death scenario due to the universe not having enough mass. Michio Kaku wrote on this last December

"The universe is out of control. Not only is it expanding but the expansion itself is accelerating. Most likely, such expansion can end only one way: in stillness and total darkness, with temperatures near absolute zero, conditions utterly inhospitable to life. That became evident in 1998, when astronomers at the Lawrence Berkeley National Laboratory and AustralianNationalUniversity were analyzing extremely distant, and thus ancient, TypeIa supernova explosions to measure their rate of motion away from us. (TypeIa supernovas are roughly the same throughout the universe, so they provide an ideal “standard candle” by which to measure the rate of expansion of the universe.)

Physicists, scrambling to their blackboards, deduced that a “dark energy” of unknown origin must be acting as an antigravitational force, pushing galaxies apart. The more the universe expands, the more dark energy there is to make it expand even faster, ultimately leading to a runaway cosmos. Albert Einstein introduced the idea of dark energy mathematically in 1917 as he further developed his theory of general relativity. More evidence came last year, when data from the Wilkinson Microwave Anisotropy Probe, or WMAP, which analyzes the cosmic radiation left over from the Big Bang, found that dark energy makes up a full 73 percent of everything in the universe. Dark matter makes up 23 percent. The matter we are familiar with—the stuff of planets, stars, and gas clouds—makes up only about 4 percent of the universe."

That depressing analysis relies on a somewhat low percentage of dark matter composing the universe.

However, something pretty sweet came out today. Astronomers may have finally found an entire galaxy made up of dark matter. While that certainly doesn't disprove the 23 percent figure cited by WMAP (and I'm no where close to being qualified to know how these two articles interact), it's interesting, at the very least. It might give some Omega Point wackoes something to be happy about.

Even so, that probably doesn't matter, given that the implosion of the Universe will, more likely than not, vaporize all life. Maybe I don't understand enough about physics, but I'm still skeptical of humanity being able to force the Taub collapse necessary for the computing power necessary to cause some sort of endless simulation of humanity.

But I really have no idea what I'm talking about.

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