Friday, December 21, 2007

sucks to be Martian

According to this article, there is currently a 1 in 75 chance that a recently discovered asteroid will slam into our next-door neighbor Mars on January 30. I love how the article ends:

In 1994, fragments of the comet Shoemaker-Levy 9 smacked into Jupiter, creating a series of overlapping fireballs in space. Astronomers have yet to witness an asteroid impact with another planet.

"Unlike an Earth impact, we're not afraid, but we're excited," [astronomer Steve] Chesley said.

Meanwhile, the Martians are going, "Fuckin' FEMA. Knew they'd never get here in time."

My question is: if we live in an age where we can pick out distant planets and even gauge their approximate size and composition, how is it that we can't get a more accurate read on this very nearby chunk of rock? Related question: why was it only recently discovered? You'd think we'd have computers tracking literally billions of asteroids by now, and not just the ones close to us.


1 comment:

  1. Finally, a chance to employ my physics minor.

    The first extra-solar planets were detected by watching for subtle, cyclical eccentricities in the motions of stars. To date there are several methods of detecting extra-solar planets, of which Wikipedia is a much better source than me. But these methods are mostly clever hacks, and rely upon the specific circumstances of the parent star.

    I'm not really tuned in to the literature, but I think guesses as to their consistency comes from watching for minute variations in high-resolution spectroscopic images. My classmates in observation lab took spectra; it's fricking hard to get really useful images.

    Of the thousands and thousands of catalogued stars, we have detected a few hundred planets. Think about it; we know exactly where to look for planets (next to stars, duh!) but we still can't find them with much regularity. As opposed to meteors, which are largely non-reflective, produce few gravitational disturbances, and could be basically anywhere. The only way we can detect them is if they are really big, really close, and happen to pass directly in front of a few steady bright objects at the same time we're looking in that direction.

    On a sidenote, when I was an astronomy student, one of the early extra-solar planet detections was done by a professor using his personal 12" scope in the university parking lot. It caused a big buzz in the astronomy community, largely because it demonstrated that serious astronomy is possible with high-level amateur gear, thanks to new technology. Expertise is now (arguably) more important than gear. Remember, astronomy is a field that has been dominated by its equipment. Wish I remembered the name; a quick Wikipedia survey doesn't turn it up.



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