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Objective – I can describe the characteristics of comets, asteroids, and meteors.
Comets, Meteors, and Asteroids Review Sheet
I. I can identify properties and characteristics of comets.
A comet is made of water ice, dry ice, frozen ammonia, dust, dirt, and rocks. A comet has been
described as a “dirty snowball” or an “icy dirtball.”
It is made up of three major parts.
Nucleus (the “dirty snowball, “icy dirtball,” or the actual comet).
Coma (vaporizing gas, ice, and dirt that surrounds the nucleus).
Tail (the gases, ices, and dirt being pushed away from the comet).
The comet’s tail always points away from the Sun. It is blown in away from the Sun by the solar
wind (particles blown out from the Sun into space).
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Objective – I can describe the characteristics of comets, asteroids, and meteors.
Comets come from two different locations. The first is the Oort Cloud. It is found
6,000,000,000,000 miles (one light year) from the Sun.
Long-period comets (comets that return every 200 years or longer) come from the Oort Cloud.
Comets also come from the Kuiper Belt. The Kuiper Belt begins just beyond the orbit of Neptune
to at least 6,000,000,000 miles from the Sun.
Short-period comets (comets that return every 200 years of less) come from the Kuiper Belt.
My daughter just thinks that all moms fly the Space Shuttle
Air Force Col. Eileen Collins, first female Space Shuttle Commander
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Objective – I can describe the characteristics of comets, asteroids, and meteors.
II. I can identify properties and characteristics of asteroids.
Asteroids are material left over from the formation of the Solar System and never formed into a
planet. Asteroids are found between the orbits of Mars and Jupiter.
Jupiter’s gravity is so strong, when a planet began to form in the Asteroid Belt, it eventually pulled
it apart. If all the asteroids were put together, it would make a world about half the size of the
Moon.
Asteroids are irregularly shaped objects. We don’t know how many asteroids are out there, but
Universe Today estimates there are millions.
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Objective – I can describe the characteristics of comets, asteroids, and meteors.
For an object to be an asteroid, it must…

orbit the Sun inside the orbit of Jupiter.
 not be round.
 not have cleared the neighborhood around its orbit.
 not be a satellite (a moon revolving around another world).
All asteroids are rocky bodies. Their diameters range from about 330 miles to about 100 meters.
Vesta is the largest asteroid. It’s about 330 miles in diameter.
If we knew exactly what to expect throughout the Solar System, we would have no reason to
explore it.
Poul (William) Anderson
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Objective – I can describe the characteristics of comets, asteroids, and meteors.
III. I can identify properties and characteristics of meteors and meteorites.
Meteors and meteorites are names for one object. These are rocky bodies and range in size from
particles of dirt to over 35 feet across.
A meteor is a rocky body the has entered into the Earth’s atmosphere. It makes a quick streak in
the sky, lasting for two or three seconds.
If the meteor is large enough, it will survive its trip through the atmosphere. When it hits the
ground, it is called a meteorite.
To go places and do things that have never been done before—that's what living is all about.
Michael Collins, Apollo 11 Astronaut
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Objective – I can describe the characteristics of comets, asteroids, and meteors.
If the meteorite is large enough, it can make a crater.
IV. I can define and use unit vocabulary correctly.
Asteroids – Irregular large pieces of rock that move through space.
Comets – Objects made up of ices, dust, and gases that orbit the sun in a large, elliptical orbit.
Gravitational Force – The measurement of the pull of gravity.
Gravity – The attraction of one mass to another.
Meteor – The streak of light produced by a small piece of matter in space that is visible when it
falls into Earth’s atmosphere.
Meteorite – Meteor that falls to the surface before burning up in the atmosphere.
Planet – A celestial object, larger than asteroids or comets that revolve around a star without
giving off its own light.
Solar System – The system made up of the eight unique planets, and many smaller objects that
orbit the sun.
Sun – The star in our Solar System that sustains most life on Earth and is the primary source of
heat and light.
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