4:32 PM — An asteroid walks into a bar...
My roommate Jethereal read an article online today (see Astronomy Picture of the Day
) that yet another asteroid barely missed Earth. This reminded me of one of the arguments for continued servicing of the Hubble Space Telescope
. The original plan for the HST, way back in the early 1990's when it still needed glasses, was that a future Shuttle mission would take Hubble back into its bay and bring it back down to Earth. This plan was later changed to adding a set of rocket boosters during the last servicing mission (you mean the one that was cancelled? *hyuk*
) that would guide any remaining debris into the ocean. See, the problem is that, left to itself, not all of the satellite will burn up during re-entry: at least the mirror will likely have parts survive. A BBC article
quotes the dubious number of a 1 in 700 chance of human death due to Hubble debris. (I say dubious because they do not cite any source for this number, and I haven't seen it anywhere else despite searching.)
But my point was, this prompted me to try to statistically determine the chance that a human could be hit by Hubble debris, or similarly, that a human could be hit by an asteroid. For the point of this (attempted) calculation, I want to ignore things like whether it'll burn up while passing through the atmosphere, and only consider the size of the meteorite when it impacts the Earth's surface. My argument is that it'll depend upon the size (cross-section, or area) of the asteroid, size of the earth, and density of people on the Earth. At this point my brain fizzles out, and I ask Jethereal to help me try and figure it out.
After much discussion, we came up with various insights, including that that it might depend upon the sizes of the asteroid and earth, and maybe even the size of people! (OMG!
) I mean,
Me: "What if the human's the size of the Earth?"
Jethereal: "No no, consider them point particles."
With the way people in the US eat? I don't think
so! (flips hair) Maybe in Ethiopia. Perhaps we should look at the problem from a different point of view.
Stay tuned for the results of our deliberations...
Jethereal: "Say there's an asteroid on the ground, and bombard the Earth with humans."
Me: "But the humans can't overlap at all, so each human hits in a different place, they're dependent events. Hm, though I guess there could be some having sex, or in tall office buildings."