Asteroid Lesson
Asteroid Lesson
Asteroid Lesson
What is an asteroid?
An asteroid is a chunk of rock and metal in outer space that is in orbit around
the Sun. Asteroids vary in size from just a few feet across to hundreds of miles in
diameter.
Most asteroids are not round, but are lumpy and shaped like a potato. As they
orbit the Sun, they tumble and spin.
Asteroid Belt
The majority of asteroids orbit the Sun in a ring called the asteroid belt. The
asteroid belt is located between the planets Mars and Jupiter. It can be belt
between the rocky planets and the gas planets. There are millions and millions
of asteroids in the asteroid belt.
Most asteroids in our solar system can be found in the asteroid belt, between Mars and Jupiter .
Where did asteroids come from?
Asteroids are from the formation of our solar system. Our solar system began
about 4.6 billion years ago when a big cloud of gas and dust collapsed. When
this happened, most of the material fell to the center of the cloud and formed
the sun.
Some of the condensing left over dust in the cloud became planets. The objects
in the asteroid belt never had the chance to be incorporated into planets. They
are leftovers from that time long ago when planets formed.
Are all asteroids the same?
No way! Because asteroids formed in different locations at different distances
from the sun, no two asteroids are alike. Here are a few ways that they differ:
Asteroids aren’t all round like planets. They have jagged and irregular
shapes.
Some asteroids are hundreds of miles in diameter, but many more are as
small as pebbles.
Most asteroids are made of different kinds of rocks, but some have clays or
metals, such as nickel and iron.
C-type Asteroids - These asteroids make up for around 75% of the asteroid
belt. The initial C stands for carbon. C-type asteroids have dark surfaces,
almost coal-black in appearance
S-type Asteroids - These asteroids make up around 17% of the asteroid
belt. They are located mostly in the inner asteroid belt, and their numbers
dwindle farther out. The initial S stands for silicaceous. They are bright
asteroids composed of metallic nickel-iron mixed with magnesium-
silicates.
M-type Asteroids - These asteroids are the rarest in the Solar System. The
initial M stands for metallic. They are relatively bright and they are mostly
composed out of pure nickel-iron. Most of them reside in the middle of
the asteroid belt.
Largest Asteroids
Some asteroids are so large that they are considered minor planets. The four
largest asteroids are Ceres, Vesta, Pallas, and Hygiea.
CLASSIFICATIONS OF ASTEROID
Main Asteroid Belt: The majority of known asteroids orbit within the asteroid
belt between Mars and Jupiter, generally with shorter orbits.
Trojans: These asteroids share an orbit with a larger planet, but do not collide
with it because they gather around two special places in the orbit.
Near-Earth Asteroids: These objects have orbits that pass close by that of the
Earth. Asteroids that actually cross Earth’s orbital path are known as Earth-
crossers. These asteroids usually explode when they hit the Earth's atmosphere
and cause little damage on the Earth's surface.
Meteoroids - Sometimes one asteroid can smash into another. This can cause
small pieces of the asteroid to break off. Those pieces are called meteoroids.
Meteoroids can also come from comets.
Comets - Comets orbit the Sun, like asteroids. But comets are made of ice and
dust—not rock.
As a comet’s orbit takes it toward the Sun, the ice and dust begin to vaporize.
That vaporized ice and dust become the comet’s tail. You can see a comet even
when it is very far from Earth. However, when you see a meteor, it’s in our
atmosphere.