2. Asteroids
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Fragments of rock that orbit the sun
Orbits are ellipses
Largest known asteroid is Ceres
Most are located in the ‘asteroid belt’
between the planets Mars and Jupiter
• Composition:
– Silicate minerals (look like earth rocks)
– Iron and nickel (shiny metallic appearance)
– Carbon (have a dark color and are rare)
3.
4. Comets
• Small bodies of ice, rock, and cosmic dust.
• Have highly elliptical orbits around the sun.
• Most originate in the Oort Cloud (spherical cloud of
dust and ice that lies far beyond Pluto’s orbit and that
contains the nuclei of billions of comets).
• Bright appearance results from sunlight reflected by
the comet’s coma
• Has Several Parts:
– core/nucleus
– Coma (together with the core form the head of the comet)
– Tail (always points a way from the sun because electrically
charged particles from the sun push it away)
5. Famous Comets
• Halley’s Comet
– Passes by Earth every 76 years
– Last passed Earth in 1986
– Will return in 2061
• Comet Hale-Bopp
– Passes by Earth every 5-10 years
– Last passed by Earth in 1997
6. Meteoroids
• A small, rocky body that travels through
space.
• Most have a diameter less than 1 mm.
• Most meteoroids burn up in the
atmosphere due to increased friction with
more molecules as it gets closer to Earth.
7. Meteor
• Bright streak of light
caused when a
meteoroid burns up in
the atmosphere.
• Also known as
“shooting stars” (click
picture)
• Picture to the right is
a meteor shower.
8. Meteorite
• Any part of a meteoroid that is left when a
meteoroid hits Earth.
• Three Types of Meteorites:
– Stony (similar to rocks on Earth)
– Iron (metallic in appearance)
– Stony-iron (contain iron and stone, are rare)
