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Coincidence of meteor strike and close asteroid approach at same time.
On Mar 6, 5:03*pm, bob haller wrote:
On Mar 6, 12:27*pm, Robert Clark wrote: *Assuming comet C/2013 A1 misses Mars by 37,000 km how much delta-v would you need to nudge it to hit Mars? This might not be purely of academic interest. Already we've seen two Earth encounters whose likelihood together was one in hundreds of millions. This comet to make a close encounter to Mars is *huge*. To put it perspective it dwarfs the asteroid that destroyed the dinosaurs. Such close encounters to any of the terrestrial planets must be very rare. For instance the puny, in comparison, asteroid 2012 DA14 would be expected to get so close to the Earth once in 40 years. That such a large comet would get so close to Mars must be much rarer than this. So the chance is less than 1 in 40 in a year. Say it happens for either of two planets; that's a chance of less than 1 in 20 in a year. Say then it happens within a 2 year period; that's 1 chance in 10. Now the chance of the three encounters occurring within such a close time span is greater than one in several billion. The unlikelihoods begin piling up greater and greater. Then we are left with the disturbing possibility there is a physical phenomenon causing these large, close encounters. And the possibility arises there is another large, close encounter to the Earth that may be upcoming. It would really become important to know then not what's the delta-v needed to turn a close miss to an impact, but in fact the reverse. Bob Clark Well aiming hazardous comets and asteroids at mars or other planets may be a good way to get rid of hazards.... theres a theory the earth has a planet killer type event every 34 million years or so. A couple weeks ago I posted we may be entering a littered part of space. Yes, you linked: http://pubs.giss.nasa.gov/docs/1985/1985_Stothers.pdf This proposes oscillation of the Sun about the galactic plane over time scales of millions of years as the cause. Other possible causes described he http://en.wikipedia.org/wiki/Extinct...s_in_frequency Bob Clark |
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