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Meteorites Composition:
  1. Small, heavy rocks and/or metal-containing bodies that are found on the ground, likely from an asteroid or comet. Composition of these bodies include iron, silicate minerals, nickel, carbon, and amino acids.
  2. Meteors are the streaks of light or falling stars that are made from a falling meteorite.
Effect of Impact:
  1. A stony meteorite 10-300 feet in diameter would disintegrate a few miles above the surface, creating a shock and heat wave that would devastate a wide area and leave only minute rock particles.
  2. Would create a crater.
Asteroids Composition:
  1. Same as meteorite, but bigger and more destructive.
  2. Contains Iridium.
Effect of Impact:
  1. Upon impact, they would create craters, fires and dust. The impact of an asteroid 1 km in diameter would cause the climate to change: the dust would block out the Sun and the polar ice caps would likely melt. There would be mini-aftershocks and mini-debris from asteroids that would hit in areas around the center of the impact.
Comets Composition:
  1. A heavenly body having a bright nucleus with a luminous mass around it and a long, luminous tail when it is close to the Sun.
  2. Comprised of vast clouds of ice, dust and organic materials.
Effect of Impact:
  1. Small comets would disintegrate in the upper atmosphere and not likely cause any surface destruction, or explode above ground, causing rocky debris to fall to Earth.
  2. A comet, 2km in diameter, is large enough to reach Earth's surface and would cause problems akin to a "nuclear winter."

Please send any comments to:
Curator:
Tom.Benson@grc.nasa.gov
Responsible Official: Kathy.Zona@grc.nasa.gov