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Stealth Asteroid Misses Earth

Posted by timothy on from the they're-sneaky-like-that dept.

Paradoxish writes: "Gah. According to cnn.com an asteroid hiding in an astronomical blindspot nearly blindsided Earth. The scary part is that scientists didn't notice it until four days AFTER it passed by. Apparently, it would've been similiar to the Tunguska explosion. Scary." As long as they keep missing Earth, we're OK.

3 of 475 comments (clear)

  1. Re:Thanks for picking on us, CNN... by curunir · · Score: 4, Insightful

    Thanks for telling me how dead I'd be if it hit here. Couldn't you have talked about it hitting somewhere where I don't live? Like Kabul, or something? Maybe Baghdad?

    They were trying to get you to imagine what the devastation might have been like. Thanks to the presidents Bush, one does not need any imagination to envision what Kabul or Baghdad would look like.

    --
    "Don't blame me, I voted for Kodos!"
  2. Are these really near misses? by Performer+Guy · · Score: 5, Insightful

    OK time for some back of the envelope math to counter the hysteria.

    461,000 kilometers was the distance it missed by. The projected target area of that circle is PI*R^2 or about 667 billion square kilometers.

    Radius of the Earth is around 6360 kilometers give or take. Projected target area of the Earth is therefore about 0.12 billion square kilometers. So the probability this class of object would collide with teh earth is roughly .12/667 or around 1/5600. Then IF it hit it would be more likely to do no damage than not depending on the impact zone.

    Of course they don't just count objects inside the 1.2X distance to the moon, range when they scream "near miss". Inside the moon, beyond the moon, they all count for the headlines.

    Excuse me for not losing any sleep.

    1. Re:Are these really near misses? by Performer+Guy · · Score: 4, Insightful

      P.S. I know it's bad probability math to post facto take the range and use that in calculations, however, it is correct to say that the chance that any future object passing within that distance would have this probability of hitting gives some simplifying assumptions. The big assumption is that theere is an even poisson distribution of events in the circular target cross section. There may not be for reasons of orbital mechanics and the gravity of the Earth skewing the results. It seems to me that these would likely work to increase the probability of a strike, unless you consider that the Earth hoovering up rocks could skew results the other way, I think when you're this close with a near miss anyway the latter effect is negligable.