Name______Class______Date______
Skills Worksheet
Directed Reading A (Lesson 19-3)
Section: Galaxies
1.A collection of stars, dust, and gas bound together by gravity is called a(n) ______.
Types of galaxies
_____2.Which of the following is one of Edwin Hubble’s contributions to science?
a.He invented the telescope.
b.He developed a way to classify galaxies.
c.He founded the field of astronomy.
d.He built the Hubble Space Telescope.
_____3.Most galaxies are classified by their
a.shape. c. age.
b.size. d. color.
_____4.Where are newly formed stars found in a spiral galaxy?
a.spiral arms c. center bulge
b.spiral halo d. outer rings
Each of the following statements is true of a spiral galaxy, an elliptical galaxy, or an irregular galaxy. Write S for a spiral galaxy, E for an elliptical galaxy, and I for an irregular galaxy in the space provided.
_____5.These galaxies contain mostly old stars.
_____6.The Milky Way is probably this type of galaxy.
_____7.Many of these galaxies may have their shape distorted by neighboring galaxies.
_____8.The arms of these galaxies are made up of gas, dust, and new stars.
_____9.These galaxies are massive blobs of stars.
_____ 10. These galaxies are close companions of another galaxy.
_____ 11. These galaxies have a bulge in the center and spiral arms.
Directed Reading A continued
contents of galaxies
_____ 12. Which one of the following statements is NOT true of nebulas?
a.Nebulas are often found in spiral galaxies.
b.Nebulas are often found in elliptical galaxies.
c.Some types of nebulas glow.
d.Some types of nebulas absorb light and hide stars.
_____ 13. All of the following are true of star clusters EXCEPT
a.A globular cluster may have as many as 1 million stars.
b.An open cluster may have only a few hundred stars.
c. An open cluster may have as many as a few thousand stars.
d.An open cluster usually has more stars than a globular cluster.
14.___Large clouds of gas and dust are called ______.
15.A tight group of stars that looks like a ball is called a(n) ______.
16. A group of stars that are closer together than the surrounding stars is called a(n) ______.
17.What is a nebula?
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18.What is a globular cluster?
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19.What is an open cluster?
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Directed Reading A continued
Match the correct description with the correct term. Write the letter in the space provided.
_____ 20. found in interstellar space
_____ 21. found in a spherical halo that surrounds a spiral galaxy
_____ 22. usually found along a galaxy’s spiral disk
origin of galaxies
_____ 23. Which one of the following statements is NOT true of quasars?
a.Quasars are among the closest objects to Earth.
b.Quasars may be caused by massive black holes in the cores of some galaxies.
c.Quasars are among the most distant objects of space.
d.Quasars are among the most powerful energy sources in the universe.
24.Why is looking through a telescope like looking back through time?
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25.Why do scientists study distant galaxies?
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Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Science and technology1Stars, Galaxies, and the Universe