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Chapter 19 Study Guide



Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 1. 

The model in which Earth is at the center of the system of planets is called the
a.
solar system.
b.
heliocentric system.
c.
geocentric system.
d.
Copernican system.
 

 2. 

Copernicus explained that
a.
the sun is at the center of the system of planets.
b.
the sun and the planets revolve around Earth.
c.
the geocentric system is correct.
d.
there are only six planets.
 

 3. 

The heliocentric system gained support when Galileo observed that
a.
one side of the moon always faces Earth.
b.
most of the smaller planets are closer to the sun.
c.
Venus goes through phases similar to those of Earth's moon.
d.
the orbit of each planet is an ellipse.
 

 4. 

The two factors that combine to keep the planets in orbit are
a.
gravity and orbital speed.
b.
orbital speed and mass.
c.
mass and inertia.
d.
gravity and inertia.
 

 5. 

The sun produces energy by
a.
attracting it with the force of gravity.
b.
nuclear fission.
c.
burning fuels such as oil.
d.
nuclear fusion.
 

 6. 

What do all of the inner planets have in common?
a.
They have the same period of revolution.
b.
They have the same period of rotation.
c.
They have the same diameter.
d.
They are small and have rocky surfaces.
 

 7. 

What do the first four outer planets have in common?
a.
They are much larger than Earth and do not have solid surfaces.
b.
They are about the same size as Earth and do not have solid surfaces.
c.
They are much larger than Earth and are solid.
d.
They are about the same size as Earth and are solid.
 

 8. 

Uranus is different from most other planets because it
a.
is the farthest from the sun.
b.
is mostly nitrogen and helium.
c.
rotates on its side.
d.
has the most moons.
 

 9. 

Pluto is different from the other outer planets because it
a.
is almost entirely made of gases.
b.
is much larger than the others.
c.
has the most moons.
d.
is small and has a solid surface.
 

 10. 

What shape are the orbits of most comets?
a.
long, narrow ellipses
b.
circles
c.
nearly circular ellipses
d.
spherical
 

 11. 

The asteroid belt is located
a.
between Earth and Mars.
b.
between Mars and Jupiter.
c.
between Jupiter and Saturn.
d.
between Saturn and Uranus.
 

 12. 

Meteoroids usually come from
a.
debris from other planets.
b.
solar winds.
c.
beyond the solar system.
d.
comets or asteroids.
 

 13. 

When a meteoroid enters Earth's atmosphere, it produces a streak of light called a
a.
meteor.
b.
asteroid.
c.
meteorite.
d.
comet.
 

Completion
Complete each sentence or statement.
 

 14. 

Most ancient astronomers thought that all celestial objects revolved around ____________________.
 

 

 15. 

The force that pulls the moon toward Earth is called ____________________.
 

 

 16. 

Nuclear fusion occurs in the ____________________, or center, of the sun.
 

 

 17. 

The tendency for an object in motion to remain in motion is called ____________________.
 

 

 18. 

The only outer planet with a solid surface is ____________________.
 

 

 19. 

A meteoroid that hits Earth's surface is called a ____________________.
 

 

 20. 

When a large ____________________ strikes Earth, it can create a crater.
 

 

 21. 

Kepler discovered that Mars' orbit is a(n) ____________________.
 

 

 22. 

The sun's energy comes from the process of _________________________, in which hydrogen atoms form helium.
 

 

 23. 

The atmospheres of the gas giants are composed mainly of the element ____________________.
 

 

Short Answer
 
 
chapter_19_study_gu_files/i0270000.jpg
 

 24. 

Write the name of the planet that is labeled with each number.
1.
2.
3.
4.
 

 25. 

Which planet is closer to the sun, the one labeled 10 or the one labeled 11? Is it always closer to the sun?
 

 26. 

What objects are found at 5? Why are they not considered to be planets?
 

 27. 

What is object 7? Compare its size and orbit to those of the planets.
 

 28. 

Name object 9 and explain why it appears different from the other gas giant planets.
 

 29. 

Explain how inertia and gravity combine to keep the planets in their orbits.
 

Essay (Answer Question #36 using a thinking map for 10 extra credit points)
 

 30. 

How are Earth and Venus similar? How is Venus different from Earth?
 

 31. 

Describe the differences among a meteoroid, a meteor, and a meteorite.
 

 32. 

Why do scientists think Europa might be a good place to look for extraterrestrial life?
 

 33. 

Explain why the outer planets did not lose the gases in their atmospheres.
 

 34. 

What caused Galileo to accept the theory that the planets revolve around the sun?
 

 35. 

Name three conditions needed for life as we know it to exist. Where in the solar system are these conditions found?
 

 36. 

Explain why some scientists do not consider Pluto to be a planet.
 



 
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