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ASTR 100 EXAM 1 ACTUAL
QUESTIONS 2026 WITH VERIFIED
ANSWERS.
What were the causes of climate (non-anthropogenic) change
in the past? (Select all that apply)
A. orbit and tilt change
B. volcanic activity and asteroids (atmospheric causes)
C. continents and oceans rearranging
D. change in greenhouse gas levels - correct answer-A. orbit
and tilt change
B. volcanic activity and asteroids (atmospheric causes)
C. continents and oceans rearranging
D. change in greenhouse gas levels
Gravity and angular momentum are both important in the
formation of planetary systems. - correct answer-True
The direction of revolution in the plane of the solar system was
determined by
A. The direction of rotation of the original cloud.
B. The amount of material in the original cloud
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C. The direction of the gravitational force within the original
cloud.
D. The plane of the galaxy in which the solar system sits. -
correct answer-A. The direction of rotation of the original cloud.
Molecular clouds collapse because of
A. Static Electricity
B. Angular Momentum
C. Gravity
D. Nuclear Reactions - correct answer-C. Gravity
Clumps grow into planetesimals by
A. gravitationally pulling in other clumps
B. colliding with other clumps
C. attracting other clumps with opposite charges
D. both a and b - correct answer-D. both a and b
Do planets affect the motion of the stars they orbit?
A. No, it is the other way around, stars make the planets go
around in orbits.
B. No, stars only move in orbits around the center of the galaxy.
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C. Yes, planets cause stars to slow down in their motion around
the galaxy.
D. Yes, stars also feel a gravitational pull from planets, but they
move much less. - correct answer-C. Yes, planets cause stars
to slow down in their motion around the galaxy.
What indicates when a protostar is considered a star?
A. the star begins to rotate
B. hydrogen fusion begins
C. the star first becomes luminous
D. the star becomes hot enough to ionize hydrogen - correct
answer-B. hydrogen fusion begins
Compared to a similar star at rest, the light received from a star
moving away from us is
A. ionized
B. shifted to shorter wavelengths
C. collisionally broadened
D. shifted to longer wavelengths
E. undetectable - correct answer-D. shifted to longer
wavelengths
ASTR 100 EXAM 1 ACTUAL
QUESTIONS 2026 WITH VERIFIED
ANSWERS.
What were the causes of climate (non-anthropogenic) change
in the past? (Select all that apply)
A. orbit and tilt change
B. volcanic activity and asteroids (atmospheric causes)
C. continents and oceans rearranging
D. change in greenhouse gas levels - correct answer-A. orbit
and tilt change
B. volcanic activity and asteroids (atmospheric causes)
C. continents and oceans rearranging
D. change in greenhouse gas levels
Gravity and angular momentum are both important in the
formation of planetary systems. - correct answer-True
The direction of revolution in the plane of the solar system was
determined by
A. The direction of rotation of the original cloud.
B. The amount of material in the original cloud
, Page | 2
C. The direction of the gravitational force within the original
cloud.
D. The plane of the galaxy in which the solar system sits. -
correct answer-A. The direction of rotation of the original cloud.
Molecular clouds collapse because of
A. Static Electricity
B. Angular Momentum
C. Gravity
D. Nuclear Reactions - correct answer-C. Gravity
Clumps grow into planetesimals by
A. gravitationally pulling in other clumps
B. colliding with other clumps
C. attracting other clumps with opposite charges
D. both a and b - correct answer-D. both a and b
Do planets affect the motion of the stars they orbit?
A. No, it is the other way around, stars make the planets go
around in orbits.
B. No, stars only move in orbits around the center of the galaxy.
, Page | 3
C. Yes, planets cause stars to slow down in their motion around
the galaxy.
D. Yes, stars also feel a gravitational pull from planets, but they
move much less. - correct answer-C. Yes, planets cause stars
to slow down in their motion around the galaxy.
What indicates when a protostar is considered a star?
A. the star begins to rotate
B. hydrogen fusion begins
C. the star first becomes luminous
D. the star becomes hot enough to ionize hydrogen - correct
answer-B. hydrogen fusion begins
Compared to a similar star at rest, the light received from a star
moving away from us is
A. ionized
B. shifted to shorter wavelengths
C. collisionally broadened
D. shifted to longer wavelengths
E. undetectable - correct answer-D. shifted to longer
wavelengths
