Transcript Comets, Meteoroids and Asteroids

Comets, Meteoroids and Asteroids
comets
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A comet is a small, icy celestial
body that orbits around the sun.
(a “dirty snowball”)
•
We see the ice turn into gas as the
comet gets near the sun.
It is made up of a:
a) nucleus- solid, frozen ice, gas and dust
b) coma- water vapor, CO2, and other gases
c) tail - made of dust and ionized gases; develops
when the comet is near the Sun. Its long tail always
points away from the sun, because of the force of the
solar wind. The tail is most of what we see.
A comet’s tail can be 250 kilometers
long!
Comets, such as Halley’s Comet, are
named by the person who discovered
them. Halley’s Comet is visible from
Earth every 76 years.
*The Oort Cloud is the area
where comets originate (come from)
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meteoroids
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meteoroids are small bodies that travel through
space.
a )smaller than asteroids; most are smaller than
the size of a pebble.
b) most come from asteroids that are broken
apart by impacts with other asteroids. Other
meteoroids come from the Moon, from comets
and from the planet Mars.
c) made from iron or nickel
How meteoroids are named:
c) meteoroid-in space;
• meteor- when it glows in Earth’s
atmosphere (a “shooting star”)
• meteorite- when falls to Earth
asteroids
• Asteroids are rocky or metallic objects in space
that revolve around the Sun.
• Most orbit the Sun in the asteroid belt between
Mars and Jupiter.
• Asteroids are also known as planetoids or minor
planets.
• There are about 40,000 known asteroids that are
over 0.5 miles (1 km) in diameter in the asteroid
belt.
• The first one discovered (and the biggest) is named
Ceres.
• 2 types:
• a) dark ones made of metal, mostly iron and
nickel
• b) lighter-colored ones made of rock
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