Impact Craterin2

Impact Craterin2 - explodes on impact The explosion is what...

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Impact Cratering There are still small chunks of rock orbiting the Sun left over from the formation of the solar system. Some of them have orbits that cross the orbits of the planets and moons. When they get close enough to a planet or moon, they will be pulled in by the large body's gravity and strike the surface at a speed of at least the escape velocity of the planet or moon, i.e., faster than a bullet. At such speeds, the projecticle explodes on impact and carves out a round bowl-shaped depression on the surface. This process is impact cratering . How can you distinguish an impact crater from a volcanic crater? Volcano craters are above the surrounding area on mountaintops while the craters from impacts are below the surrounding area with raised rims. The craters on all of the moons except Io, Mercury, and most of the ones on Mars are from impacts. The kinetic energy of the impacting meteorite or asteroid is converted into heat, sound, and mechanical energy---the projectile
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Unformatted text preview: explodes on impact. The explosion is what carves out the crater so almost all craters are round (otherwise the great majority would be oblong in shape). See the "Not Round" page from the THEMIS site for what can make an impact crater not round (links will appear in a new window). The rock on the surface of the planet or moon is bent backward, upward, and outward so the amount of material ejected is much larger than the projectile. Large craters will have a central peak formed by the rock beneath the impact point rebounding upward and they may also have terracing of the inner walls of the crater from the collapsing of the crater rim inward. The size of the craters having central peaks depends on the gravity of the planet or moon: on the Moon craters larger than about 60 kilometers in diameter have central peaks while the crater diameter on the Earth needs to be larger than just 1 to 3 kilometers....
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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