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Astro 101 Midterm (UMich) Questions and
Correct Answers
Star Ans: -glowing ball of gas, generates heat + light through
nuclear fusion
Planet Ans: -a large object that orbits a star and does not produce
its own light
-may be icy, gaseous, rock
-made spherical by gravity
Moon Ans: -objects that orbit planets; have craters because no
atmosphere
Asteroid Ans: -small object that orbits a star
-most are between Jupiter and Mars
Comet Ans: -asteroid that's cold + icy, have tails made of
evaporated ice
-come from colder, outer region of solar system
Solar System Ans: -a star and all the planets and other objects that
revolve around it [star is usually the biggest thing]
Nebula Ans: -interstellar cloud of gas and dust
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galaxy Ans: -collection of stars held together by gravity + common
center
Speed of light (how many seconds to moon, sun?) Ans: 3.00 x 10^8
m/s, moves 9.5 trillion km/year
-moon: 1 s
-sun: 8 min
Big Bang Ans: -turning H into He; primordial abundances are
thrown into atmosphere; we're made of elements originally made
of "star stuff"
Cosmic Calendar Ans: -a scale on which we compress the history
of the universe into 1 year
Earth's rotation Ans: -axis: 1/day (23.5 degrees off perpendicular)
-around sun: 1/year [west to east]; after a full orbit around sun,
stars 'return' to positions in sky
-around Milky Way center: 1/230 mil years
Constellation Ans: -a region of the sky that contains a
recognizable star pattern and that is used to describe the location
of objects in space
Milky Way Ans: -our galaxy
-a spiral plane
-center: big bulge of stars + blackhole underneath
© 2025 All rights reserved
Astro 101 Midterm (UMich) Questions and
Correct Answers
Star Ans: -glowing ball of gas, generates heat + light through
nuclear fusion
Planet Ans: -a large object that orbits a star and does not produce
its own light
-may be icy, gaseous, rock
-made spherical by gravity
Moon Ans: -objects that orbit planets; have craters because no
atmosphere
Asteroid Ans: -small object that orbits a star
-most are between Jupiter and Mars
Comet Ans: -asteroid that's cold + icy, have tails made of
evaporated ice
-come from colder, outer region of solar system
Solar System Ans: -a star and all the planets and other objects that
revolve around it [star is usually the biggest thing]
Nebula Ans: -interstellar cloud of gas and dust
© 2025 All rights reserved
, 2 | Page
galaxy Ans: -collection of stars held together by gravity + common
center
Speed of light (how many seconds to moon, sun?) Ans: 3.00 x 10^8
m/s, moves 9.5 trillion km/year
-moon: 1 s
-sun: 8 min
Big Bang Ans: -turning H into He; primordial abundances are
thrown into atmosphere; we're made of elements originally made
of "star stuff"
Cosmic Calendar Ans: -a scale on which we compress the history
of the universe into 1 year
Earth's rotation Ans: -axis: 1/day (23.5 degrees off perpendicular)
-around sun: 1/year [west to east]; after a full orbit around sun,
stars 'return' to positions in sky
-around Milky Way center: 1/230 mil years
Constellation Ans: -a region of the sky that contains a
recognizable star pattern and that is used to describe the location
of objects in space
Milky Way Ans: -our galaxy
-a spiral plane
-center: big bulge of stars + blackhole underneath
© 2025 All rights reserved
