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Big Rocks & The Mayhem That Follows
If an Earth-like planet was struck by a 1000km-diameter planetoid (a
mini-version of the Mars-sized rock that might have hit Earth and formed the moon), would it: 1) Pump enough heat into the environment to boil off the oceans? 2) Shatter the crust around the planet, or just a local continent? 3) What time scale do the effects take place over? Would it take weeks or hours for the crust to sustain its damage? Weeks or hours for the impact heat to suffuse the environment? Something in between? Mike Miller, Materials Engineer |
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Big Rocks & The Mayhem That Follows
That depends on the relative speed it was travelling. More than likely a
1000km sized object travelling at any speed has enough energy to wipe everything off this planet... in hours i'd assume... "Mike Miller" wrote in message om... If an Earth-like planet was struck by a 1000km-diameter planetoid (a mini-version of the Mars-sized rock that might have hit Earth and formed the moon), would it: 1) Pump enough heat into the environment to boil off the oceans? 2) Shatter the crust around the planet, or just a local continent? 3) What time scale do the effects take place over? Would it take weeks or hours for the crust to sustain its damage? Weeks or hours for the impact heat to suffuse the environment? Something in between? Mike Miller, Materials Engineer |
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Big Rocks & The Mayhem That Follows
"Mike Miller" wrote in message om... If an Earth-like planet was struck by a 1000km-diameter planetoid (a mini-version of the Mars-sized rock that might have hit Earth and formed the moon), would it: 1) Pump enough heat into the environment to boil off the oceans? 2) Shatter the crust around the planet, or just a local continent? 3) What time scale do the effects take place over? Would it take weeks or hours for the crust to sustain its damage? Weeks or hours for the impact heat to suffuse the environment? Something in between? Mike Miller, Materials Engineer Try using the catastrophe calculator at the link provided: http://www.lpl.arizona.edu/impacteffects/ |
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Big Rocks & The Mayhem That Follows
In article ,
Gordon D. Pusch wrote: I mis-remembered how long it takes for seismic waves to propagate through the Earth: Characteristic seismic wave velocities are actually in the range of 4--8 kps, so it will actually take less than an hour for P-waves (which are the fastest seismic waves) to propagate completely through the planet. Bear in mind that normal seismic waves are *not* shock waves. There is a difference, and it matters in this case. Again, the amount of energy involved in such a large impact is so enormous that the seismic shock waves it produces will completely shatter the crust as they propagate through it... Quite so. And because shock waves alter the properties of the material as they pass through it, they are *not* limited to the speed of sound in the original material. The speed of a shock wave depends on how energetic it is. Really energetic ones move much faster than the speed of sound. The speed of sound is the speed at which *weak* disturbances propagate. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
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Big Rocks & The Mayhem That Follows
(Christopher M. Jones) writes:
(Gordon D. Pusch) wrote in message ... (Mike Miller) writes: If an Earth-like planet was struck by a 1000km-diameter planetoid (a mini-version of the Mars-sized rock that might have hit Earth and formed the moon), would it: [...] 3) What time scale do the effects take place over? For a straight-on impact, on the order of 1.5 minutes --- the time it takes for the planetoid to move through its own diameter at escape velocity. For a glancing impact, on the order of 90 minutes --- the time it takes for the debris to orbit the Earth once. Close. Any "lithobraking" glancing impact will send the bulk of the impactor on a decidedly sub-orbital path, a mere atmospheric impact would probably not stop the impactor from simply passing through and heading back out to interstellar space. Even on the sub-orbital impact the apogee could be quite high, and it may take hours for the impactor to come around again. More likely is that substantial amounts of material from the impact (both from the impactor and the crust) will head out on low sub-orbital trajectories which will reimpact the far side of Earth on time scales closer to 45 minutes (half an orbit). As I noted in another post, "on the order of 90 minutes " means "within a power of ten of 90 minutes," i.e., probably more than 9 minutes, and probably less than 900 minutes (15 hrs). Between 45 minutes and "several hours" is certainly bracketed within that range. -- Gordon D. Pusch perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;' |
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