Near-Hit?

I bought a newspaper the other day, and while reading it, came across an interesting column headline:

Asteroid Could Collide With Mars, Scientists Say

According to the very brief article, this asteroid, called 2007 WD5, which was discovered in November, is calculated to pass very close to Mars. Earlier odds were given at 1-75 of an impact, but recent historical data on the asteroid’s path have bumped that up to 1-25. The current prediction is that if this is the 1 in 25 chance, the asteroid will hit Mars on January 30th.

Those are close odds, like really, really, really close. If this was something coming towards Earth, I’d stock up on food and water and bring along my copy of Cormic McCarthy’s The Road.

An asteroid is any object that’s smaller than 600 miles across. The largest one, around that size, is called Ceres. Most asteroids orbit the sun between Mars and Jupiter. Both plants have moons that are thought to be captured asteroids.

This isn’t the first time that something’s plowed into one of the planets – this is most likely a common occurance. One of the coolest asteroid impacts occured on one of Saturn’s moons, Mimas. The crater, which was formed billions of years ago, has turned the moon to look almost exactly like the Death Star. In 1994, 21 fragments of the Shoemaker-Levy comet impacted Jupiter, creating huge impacts in the atmosphere, releasing an incredible amount of energy.

2007 WD5 is about the size of a football field. That doesn’t sound too big, but it’s something that could do a lot of damage to the planet – an imact from an object that size would have huge rammifications for the planet. The Meteor Crater in Arizona, was formed when an object a hundred feet in length, a third of the size of the one going towards Mars, hit Earth, leaving a crater a mile in diameter. The last time earth was hit is thought to be 1908, when an asteroid landed in an uninhabited area in Sibera, exploding several miles above the surface, causing widespread devestation. Currently, it’s theorized that a 6 mile long asteroid is enough to cause a mass-extinction that would kill off the human race. 65 million years ago, a large asteroid hit what’s now Mexico, and is believed to have played a large part in killing off the dinosaurs. An earlier asteroid impact at Permian-Cretasious bountry was larger, killing off 95% of the planet’s life. 95% !

Overall, asteroid impacts are probably a fairly common occurence, when you take into account geologic time. (think big) The moon is pockmarked with major asteroid impacts that’ve left bright scars across the surface. Mars and Jupiter, who are closer to the asteroid belt, have probably been hit numerous times in their history. As I mentioned before, Earth has been hit before as well, and will probably be hit again. Currently, there are 200 known asteroids that pass over Earth’s pathway around the sun. There’s probably a lot more that we don’t know about. If I remember correctly, our next near-hit will be around 40 years from now, when one will come close to the planet. I think this sort of thing should really put into focus the fragility of our planet. Life isn’t something that should be taken for granted here – in the larger scheme of things, it hasn’t been around long, only a billion years or so, and it’s come very close to being erased, and that’s just because nature’s out to get us. A small thing like global warming is pretty good evidence that we can screw things up pretty badly on our own.

Despite all the doomsday and gloom surrounding these sorts of events (there’s really nothing that upbeat about planetary extinction), 2007 WD5 (they have to find a better name for this rock) coming close to Mars and possibly hitting it is really interesting. Scientifically, it’ll allow scientists at NASA and around the world to examine what will happen on a planet when a huge rock slams into it, and will be able to see it as it happens. I have no idea what it will mean for all the existing equipment that we have on the planet, such as Viking and the Mars Rovers. But, we do have weather satellites up there, and the amount of data that they’ll be able to collect will be immense – planetary geologists will have a field day. This is all assuming that this isn’t the 24 times that this asteroid will miss. I for one, will be following this with great interest.

In the meantime, let’s have a marathon of Deep Impact, Armageddon, the latest craptacular SciFi movie of the month, and watch the skies.

An interesting, related sidenote – I got a copy of an article entitled An Asteroid Breakup 160 MYR ago As the Probable Source of the K/T Impactor, which came out in the August issue of Nature. It’s really interesting, and talks about the place where the K/T boundry asteroid (the one from 65 million years ago), came from.

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