Astronomy 101 Exam Questions with Correct Answers Latest Update 2025-2026
Astronomers refer to the distance that light travels in one year as - Answers one light year
If the population of human beings keeps increasing on this planet, estimates are that we will
have more than ten billion members of our species on the increasingly crowded surface of the
Earth. How would you express this number (ten billion) using "Power-of-Ten" (or, "scientific")
notation? - Answers 1x10^10
The typical diameter of an atom is about .0000000001 meters. Expressed in scientific notation,
this number is equal to: - Answers 1x10^-10
The star Betelgeuse in the constellation of Orion is estimated to be 500 light years (LY) away
from Earth. Suppose that right now, Betelgeuse explodes as a supernova. In what Year would
people on Earth first become aware that Betelgeuse has exploded? - Answers in 2514 (ie. in
about 500 years from now)
For an observer standing today in San Diego (Latitude= 30 degrees north), the North Star
(Polaris) will always appear - Answers about 30 degrees above the observer's northern horizon
The Sun's radius is roughly 100 times that of the Earth. Assuming both the Sun and Earth to be
spheres, about how many times larger is the Sun's circumference than that of the Earth? -
Answers The sun's circumference is 100 times larger than that of the Earth.
The Sun's radius is roughly 100 times that of the Earth. Assuming the Earth and Sun to be
sphere, about how many times larger is the Sun's surface area than that of the Earth? - Answers
The Sun's surface area is 10,000 times larger than that of the Earth.
When you solve the following algebraic equation for x, what value do you get? 4x+2/2 = 7 -
Answers 3
The apparent path of the Sun makes around the celestial sphere during the course of a year is
calledw - Answers the ecliptic
The ancient Greek identified 7 objects that change their location night-to-night relative to the
background "fixed" stars of the celestial sphere. They dubbed these objects the "wanderers."
Which one of the "wanderers" wanders the most (i.e., changes its position the most from one
night to the next) relative to the fixed stars of the celestial sphere? - Answers the Moon.
Which ancient Greek thinkers is known to have suggested that the Earth is moving around the
Sun? - Answers Aristarchus
Which of the following is NOT an argument for showing that the Earth must be round? -
Answers The Sun is seen to be located within different constellations during the course of the
year.
, If Eratosthenes had measured the angle that the Sun made with the vertical at noon on June 22
in Alexandria to have been 14 degrees instead of 7 degrees, approximately what value would he
have estimated for the Earth's circumference? - Answers 1250,000 stadia
Polaris is currently located very close to the North Celestial Pole. However, due to the effects of
precession, we know that it has not always been located as close to the North Celestial Pole as
it is today. Of the following, at which point in the past was Polaris located farthest from the
North Celestial Pole? - Answers 13,000 years ago.
Which of the following is a correct chronological sequence of famous thinkers, ordered from
longest ago to most recent? - Answers Aristotle, Ptolemy, Copernicus, Galileo.
What specific historical event really made it possible for the three laws of planetary motion to
be discovered? (Hint: Remember that these are Reading Quizzes -- reread sections 2.1.1 and
2.1.2 in your text if you need to!) - Answers Tycho Brahe died and his assistant was able to get
full access to his data.
In physics, the term momentum is used to represent: - Answers the mass of an object multiplied
by its velocity.
The semimajor axis of the Earth's orbit around the sun is equal to: - Answers 1.0 AU
In what fundamental way did the work of Galileo differ most from his ancient predecessors who
had thought about the sky? - Answers Galileo relied on instruments and experiments to reveal to
him what Nature was doing, rather than on pure logic alone.
Which of the following has the greatest density? - Answers A cubic meter of gold.
A hypothetical planet orbits the Sun exactly once every 8 years. Its mean orbital distance to the
Sun must be equal to: - Answers 4 LY.
A single star in the process of forming starts by spinning slowly (while it is quite large and
relatively cool). As the star collapses under the pull of its own gravity, its size decreases. As a
result, its rate of spinning: - Answers will increase.
Which of the following statements about forces is FALSE? - Answers If there is no force acting
on an object, it will always be at rest with respect to surrounding objects.
The Moon is located about 60 Earth-radii away from the center of the Earth. If the moon were
located 30 Earth-radii away from the center of the Earth, the gravitational force exerted on it by
the Earth would - Answers increase by a factor of four.
The Earth has a radius of 6400 km. The space shuttle typically orbits the Earth at an altitude of
500 km above Earth's surface. To calculate the gravitational force exerted by the Earth on the
orbiting space shuttle you must use Newton's law of gravitation: F= GM1M2/ R^2 . For this
situation, the R in Newton's gravity law represents: - Answers The distance between the shuttle
Astronomers refer to the distance that light travels in one year as - Answers one light year
If the population of human beings keeps increasing on this planet, estimates are that we will
have more than ten billion members of our species on the increasingly crowded surface of the
Earth. How would you express this number (ten billion) using "Power-of-Ten" (or, "scientific")
notation? - Answers 1x10^10
The typical diameter of an atom is about .0000000001 meters. Expressed in scientific notation,
this number is equal to: - Answers 1x10^-10
The star Betelgeuse in the constellation of Orion is estimated to be 500 light years (LY) away
from Earth. Suppose that right now, Betelgeuse explodes as a supernova. In what Year would
people on Earth first become aware that Betelgeuse has exploded? - Answers in 2514 (ie. in
about 500 years from now)
For an observer standing today in San Diego (Latitude= 30 degrees north), the North Star
(Polaris) will always appear - Answers about 30 degrees above the observer's northern horizon
The Sun's radius is roughly 100 times that of the Earth. Assuming both the Sun and Earth to be
spheres, about how many times larger is the Sun's circumference than that of the Earth? -
Answers The sun's circumference is 100 times larger than that of the Earth.
The Sun's radius is roughly 100 times that of the Earth. Assuming the Earth and Sun to be
sphere, about how many times larger is the Sun's surface area than that of the Earth? - Answers
The Sun's surface area is 10,000 times larger than that of the Earth.
When you solve the following algebraic equation for x, what value do you get? 4x+2/2 = 7 -
Answers 3
The apparent path of the Sun makes around the celestial sphere during the course of a year is
calledw - Answers the ecliptic
The ancient Greek identified 7 objects that change their location night-to-night relative to the
background "fixed" stars of the celestial sphere. They dubbed these objects the "wanderers."
Which one of the "wanderers" wanders the most (i.e., changes its position the most from one
night to the next) relative to the fixed stars of the celestial sphere? - Answers the Moon.
Which ancient Greek thinkers is known to have suggested that the Earth is moving around the
Sun? - Answers Aristarchus
Which of the following is NOT an argument for showing that the Earth must be round? -
Answers The Sun is seen to be located within different constellations during the course of the
year.
, If Eratosthenes had measured the angle that the Sun made with the vertical at noon on June 22
in Alexandria to have been 14 degrees instead of 7 degrees, approximately what value would he
have estimated for the Earth's circumference? - Answers 1250,000 stadia
Polaris is currently located very close to the North Celestial Pole. However, due to the effects of
precession, we know that it has not always been located as close to the North Celestial Pole as
it is today. Of the following, at which point in the past was Polaris located farthest from the
North Celestial Pole? - Answers 13,000 years ago.
Which of the following is a correct chronological sequence of famous thinkers, ordered from
longest ago to most recent? - Answers Aristotle, Ptolemy, Copernicus, Galileo.
What specific historical event really made it possible for the three laws of planetary motion to
be discovered? (Hint: Remember that these are Reading Quizzes -- reread sections 2.1.1 and
2.1.2 in your text if you need to!) - Answers Tycho Brahe died and his assistant was able to get
full access to his data.
In physics, the term momentum is used to represent: - Answers the mass of an object multiplied
by its velocity.
The semimajor axis of the Earth's orbit around the sun is equal to: - Answers 1.0 AU
In what fundamental way did the work of Galileo differ most from his ancient predecessors who
had thought about the sky? - Answers Galileo relied on instruments and experiments to reveal to
him what Nature was doing, rather than on pure logic alone.
Which of the following has the greatest density? - Answers A cubic meter of gold.
A hypothetical planet orbits the Sun exactly once every 8 years. Its mean orbital distance to the
Sun must be equal to: - Answers 4 LY.
A single star in the process of forming starts by spinning slowly (while it is quite large and
relatively cool). As the star collapses under the pull of its own gravity, its size decreases. As a
result, its rate of spinning: - Answers will increase.
Which of the following statements about forces is FALSE? - Answers If there is no force acting
on an object, it will always be at rest with respect to surrounding objects.
The Moon is located about 60 Earth-radii away from the center of the Earth. If the moon were
located 30 Earth-radii away from the center of the Earth, the gravitational force exerted on it by
the Earth would - Answers increase by a factor of four.
The Earth has a radius of 6400 km. The space shuttle typically orbits the Earth at an altitude of
500 km above Earth's surface. To calculate the gravitational force exerted by the Earth on the
orbiting space shuttle you must use Newton's law of gravitation: F= GM1M2/ R^2 . For this
situation, the R in Newton's gravity law represents: - Answers The distance between the shuttle
