Comets and Meteors
Comets• Large, icy dirt-ball• Contains dust, ice,
carbon dioxide, ammonia, methane and more
• Most comets ~ 16km across
Comets• Comets orbit the sun, but
have very large orbits • The orbits come from a
region beyond Pluto, called the ‘Oort Cloud’
Comets• Scientists think some comets come from a
band of icy objects called the “Kuiper belt”, beyond Neptune’s orbit
Comets• Some comets, called ‘sun-grazers’, smash right
into the sun or get so close that they break up and evaporate.
Comets• When a comet gets closer
to the sun, the ice turns into a gas cloud (called a ‘coma’)
• Solar radiation pushes dust from the sun, forming a dust tail
• Charged particles convert some of the sun’s gases, forming an ion tail
Tails always point away from the sun.
Comets• Comets leave a trail of debris behind them
that can lead to meteor showers on Earth.• Some famous comets:– Haley’s Comet– Comet Hale-Bopp– Comet Shoemaker-Levy– Comet Holmes
Meteors• Meteors (“shooting
stars”) are tiny bits of dust and space rocks that fall through the atmosphere.
• They heat up so much that they become a fiery streak across the night sky.
Meteors• Meteor showers happen
when Earth passes through a region of space that a comet passed through before
• During these times, you can see 1-2 shooting stars per minute!
Meteors• Most meteors are the size of a grain of sand• They burn up completely in the atmosphere
Meteors• Upcoming meteor showers:– Geminids, Dec.13 – Dec.14– Quadrantids, January 3– Lyrids, April 21– Eta Aquarids, May 5
Meteors• Meteors that are big enough to make it all the
way to the ground are called ‘meteorites’
Meteors• Finding one is a pretty big deal!
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