Download Handout 3 1-2 ppt

Handout 3 (1-2)
Chpater’s 28-4 and 30-3
Asteroids, Comets, and Meteroroids
And
Star Groups
Handout 28-4
Asteroids, Comets, and Meteoroids
1. In addition to the sun, planets, and their
moons, what occupies the space in our
solar system?
• The solar system includes million of smaller
bodies; some are tiny bits of dust or ice;
others are as large as small moons.
2. What are asteroids?
• fragments of rock that orbit the sun
3. Most asteroids are found in the
asteroid belt located
• between the orbits of Mars and Jupiter.
4. The composition of asteroids is
similar to that of the
• inner planets.
5. For what reason do many astronomers
think that asteroids in the asteroid belt
were not able to form a planet?
• because of the strong gravitational force of
Jupiter
6. What is a comet?
• a small body of ice, rock, and cosmic dust that
orbits the sun
7. A comet’s spectacular tail forms
when
• sunlight changes the comet’s ice to gas.
Matching 8-13
8. meteor
9. meteor shower
10 iron meteorite
.
11 stony meteorite
.
a.
a large number of meteoroids entering
Earth’s atmosphere in a short period of
time.
b. a bright streak of light that results when
a meteoroid burns up in Earth’s
atmosphere
c. a meteorite similar in composition to
rocks on Earth that may contain carbon
compounds
d. the rarest type of meteorite
12 meteorite
.
e.
a meteoroid or any part of a meteoroid
that is left when it hits Earth
13 stony-iron meteorite
.
f.
a meteorite with a distinctive metallic
appearance
Types of Meteorites
Fifty thousand years ago, a giant fireball
streaked across the North American
sky. It struck the earth in what is now
northern Arizona, exploding with the
force of 2 ½ million tons of TNT.
14. Why are the oldest meteorites
important?
• Because they may be 100 million years older
than Earth and its moon, and thus may
provide information about how the early solar
system formed.
Handout 30-3
Star Groups
1. What is a galaxy?
• a large-scale group of stars, gas, and dust
bound together by gravity
2. What is the diameter of the Milky
Way?
• about 100,000 light-years
3-6 Matching
3. elliptical
galaxy
a. varies from almost spherical to a
stretched out football in shape
and has a bright center
4. barred spiral
galaxy
b. has a nucleus of bright stars and
flattened arms that circle around
the nucleus
c. has a no particular shape and
may have a low total mass
5. irregular
galaxy
6. spiral galaxy
d. has a straight bar of stars that
runs through the center
Types of Galaxies
7. What does the Milky Way look like
in the night sky?
• a cloudlike band that stretches across the sky
8. How is the sun related to the Milky
Way?
• It is one of hundreds of billions of stars in the
Milky Way.
9. How long does it take the sun to
orbit around the Milky Way?
• About 225 million years
10. What are the closest neighbors to
the Milky Way?
• Two irregular galaxies called the Large
Magellanic Cloud and the Small Magellanic
Cloud
11. How far from Earth are the Milky
Way’s closest neighbors?
• More than 170,000 light-years away from
earth
THE END???