Asteroids

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Asteroids

• Lab 10

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Asteroid Belt

• Most asteroids are believed to be remnants of the
  protoplanetary disc which were not incorporated
  into planets during the solar system's formation
  
• Some asteroids have moons
• Vast majority of the asteroids are within the
  asteroid belt, with elliptical orbits between
  those of Mars and Jupiter, about 2.8 AU from Sun
  
• Asteroids are rocky, metallic objects that orbit
  the Sun, too small to be considered planets.
  
• Asteroids range in size from about 1000 km down
  to the size of pebbles

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• If total mass of all asteroids was gathered into
  a single object, the object would be less than
  1,500 kilometers (932 miles) across -- less than
  half the diameter of our Moon
• Asteroids that are on a collision course with
  Earth are called meteoroids

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DOOMSDAY ASTEROID

• First spotted June 19, 2004 in AZ
• Seen again at Xmas in Australia
• Is 1000 ft wide
• Probability of it hitting earth rose from 1170
  to 138
  
• Impact would come on Friday the 13th in April 2029

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Asteroid 2004 MN4

• After recalculations, belief is Asteroid 2004 MN4
  will miss Earth by 15,000-25,000 miles which is
  one-tenth the distance to the moon
  
• Asteroid 2004 MN4 is a "regional" hazard -- big
  enough to flatten Texas or a couple of European
  countries with an impact equivalent to 10,000
  megatons of dynamite -- more than all the nuclear
  weapons in the world

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Really, really bad asteroid!

• In 2029, the close encounter with Earth will
  increase the size of the orbit, and the object
  could get into a resonance with the Earth
  
• Could get orbit matchups every five years or nine
  years, or something in between
  
• In fact, 2004 MN4 could come close again in 2034,
  2035, 2036, 2037, 2038 or later
  
• Read all about it at http//impact.arc.nasa.gov/