Meteors

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Meteors
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Ground Zero

• What is the chance of being near (within 1 km) a
  meteor as it strikes the ground during your
  lifetime?
• A. About 1 in a thousand.
• B. About the same as winning the lottery.
• C. About the same as winning the Nobel Prize in
  physics.
• D. Virtually impossible.

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Shooting Stars

• Objects in space move very quickly compared to
  Earth.
• Any object entering the earths atmosphere from
  space will heat up and glow.
• These bright objects streak across the sky as
  meteors.

meteor
atmosphere
earth
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Meteorites

• Some meteors do not entirely burn up.
• Outer layers of a meteor protect the core
• The atmosphere slows it down
• The remaining rock that reaches earth is a
  meteorite.

meteor
meteorite
earth
earth
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Types of Meteorites

• Meteors match the types of material in comets
  (95) and asteroids (5).
• Comets mainly ice - few reach ground
• Asteroids mainly rock - makes most of the
  meteorites

Carbon chondrites 4
Stony meteorites 88
Metallic meteorites 8
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Finding Meteorites

• About 10 to 50 meteorites land each day, or about
  10,000 meteorites land per year.
• Earths surface about 500 million square km
• 1 meteorite per 1 square km every 50,000 years
• About 1/1000 that one will land near you during
  your life
• The surface of the Earth hides most meteorites.
• 2/3 of the meteorites land in the ocean
• 1/4 of those on land are in desolate areas
  (deserts, poles)
• Antarctica is a good place for meteorite hunting.

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Planet Parts

• Meteorites can be matched to planetary surfaces.
• Spectral analysis
• Matches to Moon, Mars, asteroids
• These meteorites were blasted from their parent
  planet.

Meteorite from the asteroid Vesta
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Jupiter Impact

• Comet Shoemaker-Levy 9 struck Jupiter in 1994.
• Broke up before impact.
• Pieces damaged Jupiters atmosphere

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Earth Impact

• Meteor Crater, Arizona
• Impact 50,000 years ago
• Object 40 meters in diameter
• Iron composition

• Tunguska, Siberia, Russia
• Impact June 30, 1908
• Object 60 meters in diameter
• Stony composition

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Extinction

• An object the size of Shoemaker-Levy 9 collided
  with the earth 65 million years ago.
• 180 km crater
• 12 km object
• Debris blocked sunlight
• Plants and animals went extinct