Astronomy 101 Practice questions and
Verified Answers
(Q04.03) Which of the following best describes why the moon goes through phases? -
ANSWER We see only part of the lit-up half of the moon depending on its position relative to
the Earth and Sun
(Q04.04) Suppose you see the Moon rising at the same time as the Sun is setting. What is
the phase of the Moon? - ANSWER Full Moon
(Q04.05) You see the Moon rising at midnight. What will the phase of the Moon be in one
week? - ANSWER Full Moon, Waning gibbous, Third quarter, Waning crescent (NONE OF
THE ABOVE)
(Q04.06) Which of the following groups of moon phases can be seen (above the horizon)
at 3am? - ANSWER Third quarter, Full moon, Waning gibbous
(Q04.07) Which of the above situations occurs at a time closest to sunset? - ANSWER
"C" (waning crescent rising)
(Q04.08) When the Moon appears to completely cover the Sun (a solar eclipse), the Moon must
be in which phase? - ANSWER New Moon
(Q05.01) One evening at midnight, you observe Leo high in the southern sky at midnight. Virgo
is to the east of Leo and Cancer is to the west. One month earlier, which of these
constellations was high in the southern sky at midnight? - ANSWER Cancer
(Q05.02) One night you see the star Sirius rise at exactly 7:36pm. The following night it will rise -
ANSWER slightly earlier
, (Q05.03) What component of Earth's motion causes the stars to rise earlier on
successive nights? - ANSWER Its orbit around the Sun
(Q06.01) How does the parallax of a distant object compare to the parallax of a nearby object?
- ANSWER The nearby object has a larger parallax compared to a distant object
(Q06.02) Which of the following planetary orbits is the most eccentric? - ANSWER "D"
(Most elliptical orbit)
(Q06.03) The extreme distances of a planet around its parent star is shown. What is the
semi-major axis of the planet? - ANSWER 10AU (15AU major axis, 5AU minor axis)
(Q06.04) The ellipse in the figure represent the orbit of a planet around a star. Which correctly
identifies a possible location for the star? - ANSWER "C" (the orbit is eccentric so the star has to
be at one end of the orbit)
(Q06.05) During which part of the planet's orbit (A-D) is the planet moving fastest? -
ANSWER "C" (because the planet is closest to the star)
(Q06.06) During how many portions of the planet's orbit (A,B,C,D) would the planet be
speeding up the ENTIRE TIME? - ANSWER Two (as it is approaching the star and when it is
directly next to the star)
(Q06.07) Suppose the Earth suddenly became 10 times more massive than it is now. How would
this affect the length of a year (i.e. how long it takes Earth to orbit the Sun)? - ANSWER The year
would be shorter (?)
(Q06.07) Jupiter is roughly five times further from the Sun than the Earth. How does the time
it takes Jupiter to go around the Sun compare to the time it takes the Earth? - ANSWER It takes
Earth longer to orbit the Sun
Verified Answers
(Q04.03) Which of the following best describes why the moon goes through phases? -
ANSWER We see only part of the lit-up half of the moon depending on its position relative to
the Earth and Sun
(Q04.04) Suppose you see the Moon rising at the same time as the Sun is setting. What is
the phase of the Moon? - ANSWER Full Moon
(Q04.05) You see the Moon rising at midnight. What will the phase of the Moon be in one
week? - ANSWER Full Moon, Waning gibbous, Third quarter, Waning crescent (NONE OF
THE ABOVE)
(Q04.06) Which of the following groups of moon phases can be seen (above the horizon)
at 3am? - ANSWER Third quarter, Full moon, Waning gibbous
(Q04.07) Which of the above situations occurs at a time closest to sunset? - ANSWER
"C" (waning crescent rising)
(Q04.08) When the Moon appears to completely cover the Sun (a solar eclipse), the Moon must
be in which phase? - ANSWER New Moon
(Q05.01) One evening at midnight, you observe Leo high in the southern sky at midnight. Virgo
is to the east of Leo and Cancer is to the west. One month earlier, which of these
constellations was high in the southern sky at midnight? - ANSWER Cancer
(Q05.02) One night you see the star Sirius rise at exactly 7:36pm. The following night it will rise -
ANSWER slightly earlier
, (Q05.03) What component of Earth's motion causes the stars to rise earlier on
successive nights? - ANSWER Its orbit around the Sun
(Q06.01) How does the parallax of a distant object compare to the parallax of a nearby object?
- ANSWER The nearby object has a larger parallax compared to a distant object
(Q06.02) Which of the following planetary orbits is the most eccentric? - ANSWER "D"
(Most elliptical orbit)
(Q06.03) The extreme distances of a planet around its parent star is shown. What is the
semi-major axis of the planet? - ANSWER 10AU (15AU major axis, 5AU minor axis)
(Q06.04) The ellipse in the figure represent the orbit of a planet around a star. Which correctly
identifies a possible location for the star? - ANSWER "C" (the orbit is eccentric so the star has to
be at one end of the orbit)
(Q06.05) During which part of the planet's orbit (A-D) is the planet moving fastest? -
ANSWER "C" (because the planet is closest to the star)
(Q06.06) During how many portions of the planet's orbit (A,B,C,D) would the planet be
speeding up the ENTIRE TIME? - ANSWER Two (as it is approaching the star and when it is
directly next to the star)
(Q06.07) Suppose the Earth suddenly became 10 times more massive than it is now. How would
this affect the length of a year (i.e. how long it takes Earth to orbit the Sun)? - ANSWER The year
would be shorter (?)
(Q06.07) Jupiter is roughly five times further from the Sun than the Earth. How does the time
it takes Jupiter to go around the Sun compare to the time it takes the Earth? - ANSWER It takes
Earth longer to orbit the Sun
