The distance between stars is typically measured in
_____________________.
What is a light-year
Pg. 834
100
Which kind of star is most likely to spend the longest time on the main sequence?
a. a low-mass red star c. a high-mass blue star
b. a yellow star like the sun d. a bright white star
What is A. a low-mass red star
Pg. 841
100
Why is studying star clusters useful, what do they have in common?
What is the stars are about the same age and distance from Earth.
Pg. 847
100
Hubble’s Law states that the speed at which a galaxy is moving away is proportional to the
a. mass of the galaxy.
b. number of stars in the galaxy.
c. galaxy’s distance from Earth.
d. age of the galaxy.
What is C. galaxy’s distance from Earth
Pgs. 852-3
200
For the sun to be stable, the inward and outward forces within the sun must be
a. in equilibrium.
b. part of the fusion reaction.
c. focused in the core.
d. balanced with temperature and density.
What is A. in equilibrium
Pg. 829
200
Astronomers classify stars according to their
a. distance from Earth.
b. color, size, and absolute brightness.
c. age and parallax.
d. all of the above
What is B. color, size, and absolute brightness
Pgs. 836-838
200
The life cycle of a star begins with a cloud of gas and dust called a
a. protoplanet. c. nebula.
b. constellation. d. protosun.
What is a nebula.
Pg. 841
200
Galaxies are classified into four groups based on their
a. shapes. c. number of stars.
b. sizes. d. brightness.
What is A. shapes
Pg. 848
200
Dark matter can be detected by its
a. cosmic microwave background radiation.
b. red shift.
c. gravitational effects on visible matter.
d. velocity.
What is C. gravitational effects on visible matter.
Pg. 855
300
A stream of electrically charged particles sent into space by the sun is called ___________________.
What is solar wind
Pg. 831
300
An H-R diagram
a. is a map of the positions of the stars.
b. graphs stars according to their size and distance.
c. lists every known star.
d. graphs a sample of stars according to surface temperature and absolute brightness.
What is B. graphs stars according to their size and distance
Pg. 838
300
All stars remain on the main sequence
a. until they stabilize. protostars.
b. for about 90 percent of their lifetimes.
c. until they become
d. for about 10 billion years.
What is B. for about 90 percent of their lifetimes
300
How do open star clusters differ from associations?
a. Associations are typically larger.
b. Open clusters are organized into constellations.
c. Associations are usually smaller and have more stars.
d. Open clusters typically contain loose groupings of old stars.
What is A. Associations are typically larger.
Pg. 847
300
How can an object’s red shift tell us how fast the object is moving away from Earth?
What is the larger the observed shift, the faster the speed.
Pgs. 852-3
400
The sun’s major source of fuel is ____________________.
What is hydrogen
Pg. 829
400
The apparent change in position of an object with respect to a distant background is called ____________________.
What is a parallax.
Pg. 835
400
A young star forms when the pressure from ____________________ supports the star against the tremendous inward pull of gravity.
What is fusion.
Pg. 841
400
New stars are not forming in older ____________________ galaxies.
What is an elliptical
Pg. 848
400
The observation that cosmic microwave background radiation is detected in all directions in the universe supports the hypothesis that the universe is ____________________.
What is expanding.
Pg. 855
500
The two forces that are balanced when a star is in equilibrium are outward pressure and ____________________.
What is gravity.
Pg. 829
500
The main sequence lifetime of a star is dependent upon the star’s ____________________.
What is the mass.
Pg. 837
500
The sun will end its life as a red giant and eventually end up as a(an) _________________________.
What is white or black dwarf
Pg. 834
500
What is a group of stars called that appears to form a pattern when seen from Earth?
What is a constellation.
Pg. 846
500
To what do astronomers attribute the increasing rate of expansion of the universe?
What is a mysterious force called dark energy.
Pg. 855