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Astronomy 209 / ASTR 209 Midterm Exam –
Latest 2026/2027 Update | Practice Review with
Verified Questions & Answers | Grade A
What celestial line is a product of the Earth's orbit around the Sun?
Ecliptic
The heliocentric model was actually first proposed by:
Aristarchus.
Tycho Brahe's contribution to Kepler's Laws of Planetary Motion was:
his detailed and accurate observations of the planet's position
According to Kepler's third law, the square of the planet's period in years is:
proportional to the cube of its semimajor axis in A.U
Define Zenith
the point in the sky or celestial sphere directly above an observer
Where on Earth can you observe all the stars in the sky over an entire year?
the equator
The stars appear to be attached to a sphere that surrounds the Earth and rotates above, causing
the apparent rising and setting of the stars. This is called the:
celestial sphere.
The places where the Sun crosses the equator are called the:
equinoxes.
Which are the key observations made by Galileo that challenged widespread philosophical
beliefs about the solar system?
- Jupiter has orbiting moons.
- The Moon has mountains, valleys, and craters.
- The Sun has sunspots and rotates on its axis.
- Venus goes through a full set of phases.
The angular size of an object depends on which two quantities?
the object's actual size and its distance from us
, The place the Sun stops its northward motion along the ecliptic is the:
summer solstice.
Into how many constellations is the celestial sphere divided?
88
A "light-year" is a unit used for what kind of measurement?
distance
The force of gravity varies with the:
product of the two masses and the inverse square of the distance separating the two bodies.
The temperature scale that places zero at the point where all atomic and molecular motion ceases
is:
Kelvin
Colors appear different to us because of their photons' different:
frequencies
If the distance between two asteroids is doubled, the gravitational force they exert on each other
will:
be one fourth as great.
The total energy radiated by a blackbody depends on:
the fourth power of its temperature.
According to Wein's Law, if the surface temperature is increased by a factor of 2, its peak
wavelength will:
decrease by a factor of 2
Very low temperature molecular clouds emit most of their light in which part of the
electromagnetic spectrum?
the radio
The number of waves passing the observer per second is:
the frequency in Hertz.
Of all the forms of electromagnetic radiation, the one with the lowest frequency is:
radio waves.
At which of these Kelvin temperatures would a blackbody radiate mostly at visible wavelengths?
the highest temperature
Astronomy 209 / ASTR 209 Midterm Exam –
Latest 2026/2027 Update | Practice Review with
Verified Questions & Answers | Grade A
What celestial line is a product of the Earth's orbit around the Sun?
Ecliptic
The heliocentric model was actually first proposed by:
Aristarchus.
Tycho Brahe's contribution to Kepler's Laws of Planetary Motion was:
his detailed and accurate observations of the planet's position
According to Kepler's third law, the square of the planet's period in years is:
proportional to the cube of its semimajor axis in A.U
Define Zenith
the point in the sky or celestial sphere directly above an observer
Where on Earth can you observe all the stars in the sky over an entire year?
the equator
The stars appear to be attached to a sphere that surrounds the Earth and rotates above, causing
the apparent rising and setting of the stars. This is called the:
celestial sphere.
The places where the Sun crosses the equator are called the:
equinoxes.
Which are the key observations made by Galileo that challenged widespread philosophical
beliefs about the solar system?
- Jupiter has orbiting moons.
- The Moon has mountains, valleys, and craters.
- The Sun has sunspots and rotates on its axis.
- Venus goes through a full set of phases.
The angular size of an object depends on which two quantities?
the object's actual size and its distance from us
, The place the Sun stops its northward motion along the ecliptic is the:
summer solstice.
Into how many constellations is the celestial sphere divided?
88
A "light-year" is a unit used for what kind of measurement?
distance
The force of gravity varies with the:
product of the two masses and the inverse square of the distance separating the two bodies.
The temperature scale that places zero at the point where all atomic and molecular motion ceases
is:
Kelvin
Colors appear different to us because of their photons' different:
frequencies
If the distance between two asteroids is doubled, the gravitational force they exert on each other
will:
be one fourth as great.
The total energy radiated by a blackbody depends on:
the fourth power of its temperature.
According to Wein's Law, if the surface temperature is increased by a factor of 2, its peak
wavelength will:
decrease by a factor of 2
Very low temperature molecular clouds emit most of their light in which part of the
electromagnetic spectrum?
the radio
The number of waves passing the observer per second is:
the frequency in Hertz.
Of all the forms of electromagnetic radiation, the one with the lowest frequency is:
radio waves.
At which of these Kelvin temperatures would a blackbody radiate mostly at visible wavelengths?
the highest temperature
