Sunday, December 07, 2008

On Asteroids

And, on the matter of risk, how are we to respond to the possibility of an asteroid impact? There's running around screaming, of course, or, at the other end of the scale, there's the if-an-asteroid's-got my-number-on-it shrug. The anti-asteroid programme being suggested is over at the screaming end of things and seems to be a very ambitious attempt to make the universe a bit safer for people.  The short-sighted dinosaurs never saw the need. I am tempted to see such impacts as forest fires - violent but necessary. After all, if the one that wiped out the dinosaurs hadn't happened, the mammals could never have made their move. Come, friendly asteroids, and fall on earth.

11 comments:

  1. I have always thought of asteroid impact as more of a danger than Catastrophic Anthropogenic Global Warming (CAGW), and potentially more easily prevented, or mitigated.

    One of the things that puzzles me is, as mentioned in the referenced article, of deflecting the asteroid by crashing a spacecraft into it. I don't see the advantage of this over 'landing' on the asteroid and running one's engines steadily for a long time. In both cases, the same amount of fuel would (in the best case for collision) provide the same amount of deflection. However, surely the collision option has many more risks: one might miss, the asteroid might break up and then present multiple dangers with the same total kinetic energy, the energy put into breaking up the asteroid is not available for deflection.

    It would surely be better to have a dual plan: early detection and long-term controllable deflection with rocket motors; last-minute explosive and less-controllable deflection.

    Also, is there not also possible benefit, say against medium-sized asteroid strike, of accurate prediction of impact point, together with large-scale planned evacuation.

    Best regards

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  2. I think we all know the real solution involves nuclear warheads and Bruce Willis.

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  3. Sounds to be like a make work project for scientists with mortgages and bills to pay.

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  4. My asteroids have been acting up all weekend.
    However, this restored the good humour. You couldn't make it up, could you.

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  5. are you saying the dinosaurs might come back?

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  6. I'm not worried. If an asteroid ever threatens us, I'm sure we can all count on the Americans to do something clever. OTOH, I do worry that if we put the UN in charge they'll end up finding a way to attract them.

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  7. Hurry up indeed all you good asteroids out there before these crazy bastards get a government grant.

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  8. Presumably, Bryan would feel somewhat differently about this if the astronomers announced that one on a clear trajectory to hit the earth in the next few years had just been spotted.

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  9. What chance an asteroid attack, Bryan?

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  10. Here is a list of known close biggish asteroid approaches: http://neo.jpl.nasa.gov/cgi-bin/neo_ca?type=PHA&hmax=24&sort=date&sdir=ASC&tlim=future&dmax=5LD&max_rows=20&fmt=full&action=Display+Table&show=1

    A date to watch 13th April 2036 (I suspect the 2029 date in the above link is a typo), as Adophis comes within about 1/10 of the lunar distance. It is estimated to be 270 metres in diameter and travelling at around 7.5km/s. The current Earth impact probability is 1 in 45,000 and impact energy is the equivalent of 506 megatonnes of TNT.

    Best regards

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  11. I'd be more worried about gamma ray bursts from Quasars and Hypernovas.

    nothing more humbling then becoming the ant under the magnifying glass.

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