Transcript Asteroids, Comets, and Meteorites, Oh My! - Willoughby

Asteroids, Meteroids, and
Comets…Oh my!
Asteroids
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Asteroids – A rocky lump of frozen gas
that can range in size from a few hundred
feet to several hundred miles wide.
Matter that is similar in composition to the
planets. Sometimes, it’s called a
Planetoid.
Orbit in a belt between Mars and Jupiter.
Largest asteroid known: Ceres (1801)
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Asteroid Gaspra – photographed by
the Galileo spacecraft in 1991.
What prevents the Asteroids in the
belt from plunging into the sun and
hitting the inner planets in the
process?
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The Sun’s gravity and Jupiter’s
gravity!
Meteoroids
Meteoroids – Small fragments of
matter, like rock, stone, and metals
(smaller than asteroids) that orbit
the sun at a variety of speeds; pieces
of planets, moon, or asteroids
 Meteor - “shooting star”
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• This happens when a meteoroid enters
Earth’s atmosphere and begins to burn.
• Briefly visible
• Fireball – Long streaks of bright light
created by these racing meteors
Fireball from a meteor in the night
sky.
 Pennsylvania 1992
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Sometimes meteors strike Earth!
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Meteorite – a meteor that impacts the
ground.
• Most meteorites fall into the oceans.
• Most meteorites fall to earth as dust,
because they burn up in the atmosphere.
• “Micrometeorites” strike Earth daily. These
can be as small as pebbles.
• Size of a mountain every 10,000 years.
• Craters are created when large meteorites
strike a moon or planet.
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3 km wide in Quebec, Canada
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Largest Meteorite to strike US – Oregon
1902
1954 – crashed through the living room
and injured a woman.
What’s the difference between a
meteoroid, meteor, and meteorite?
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Meteoroid – still in space
Meteor – enters earth’s
atmosphere
Meteorite – meteor that
strikes earth because it’s
so big it doesn’t burn up.
Seen during a football
game.
Pieces of it crashed into
the trunk of a parked car.
Meteor Shower
The 1966 Leonids Meteor Shower
 Arizona; 2300/minute for 20 minutes
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Comets
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Comets – lumps of frozen gas and rock that orbit
the sun in a highly eccentric way.
A heavenly body that is usually named after its
discoverer.
Believed to originate in an Oort cloud. (Huge cloud
that is thought to surround our solar system).
Nucleus – the center of a comet.
Coma – large halo of gas and dust that forms
around the nucleus of a comet when it gets close to
the sun. It actually loses mass as it gets close to
the sun.
More about a comet
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Comets orbit the sun in an elliptical
pattern.
Comets have tails. Their tails are made
of frozen gases, cosmic dust, and rocky
particles. As a comet travels toward the
sun, its head leads the way. But as it
travels away, its tail leads the way. This is
due to Solar winds.
Haley’s comet – a space curiosity that
returns to Earth’s view every 76 years.
Haley’s Comet
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It has been spotted for thousands of years.
Sir Edmond Halley – English
astronomer (1656-1742)
Can you find Haley’s Comet in the
tapestry below dated from 1066 A.D.?