# Introductory Astronomy: Old Test Questions

Tests from fall 2017, astronomy 138.
Test 1 (PDF)
Test 2 (PDF)
Test 3 LG list (PDF) (for grand tour section only - recall that tests are cumulative.)
Test 3 (PDF)
Test 4 review questions and tidbits (PDF)

Here are some tests from spring 2015: Test 2 (PDF) | Test 3 (PDF) | Faux Final (PDF) | Test 4 (PDF).

A collection of older questions (below) are arranged in categories: sky behavior and astronomy history, light and telescopes, inner planets, outer planets, comets and asteroids, the sun, stars, galaxies, cosmology, and life in the universe. My courses can change substantially from semester to semester even for the same course number. Therefore, not all of these questions will apply perfectly to your exact situation.

# Sky behavior and Astronomy History

At [sunset/midnight/sunrise/noon], a moon that is overhead is in what phase?
new
first quarter
full
last quarter
The formula P2 = a3 is an expression of
Newton's second law
Kepler's first law
Kepler's second law
Kepler's third law
At what time is a [first-quarter/full/last-quarter/new] moon overhead?
12 noon
6 p.m.
12 midnight
6 a.m.
The daily rotation of the earth has what consequence?
The sun moves along the ecliptic about 1° a day.
The moon shows phases.
Time exposures of the night sky show star trails.
In May, the sun is really in Aries, not Taurus like the astrology columns all say.
What is 2 × 106 multiplied by 10-3?
2 × 10-3
2 × 103
2 × 109
1/2 × 10-3
A young, hip civilization on the planet Bebop has two cities almost directly north and south of each other. Vertical sticks placed at both cities show that the sun's angle is 10° different between the two cities, which are 1000 km apart. What is the circumference of planet Bebop?
360 km
3,600 km
36,000 km
360,000 km
The name for the average sun-to-earth distance is
a parsec.
an astronomical unit.
a light year.
a year.
The sun's path (ecliptic) and the celestial equator cross at
the equinoxes.
the zodiac.
the nexus.
the precession.
On June 21, the summer solstice, you are vacationing on a cruise ship in the Pacific ocean. The Captain tells you that the ship is located on the Tropic of Cancer. (It is summer in the northern hemisphere, and the Tropic of Cancer is the northern tropic.) That noon, you can expect the sun to pass
23.4 degrees north of the southern horizon.
23.4 degrees north of the zenith.
23.4 degrees south of the zenith.
What did Galileo not see?
Mountains on the earth's moon.
Uranus's moons Titania and Oberon.
Jupiter's 4 largest moons.
The phases of Venus.
Let's suppose the force that the sun exerts on Mars is exactly 1022 Newtons. What would the force be if Mars were twice as far away?
0.25 × 1022 N.
0.5 × 1022 N.
2.0 × 1022 N.
4.0 × 1022 N.
by inner planets.
by the moon.
by outer planets.
during eclipses.
To have a solar eclipse, the sun, moon, and earth are in this order:
moon-sun-earth
sun-earth-moon
sun-moon-earth
earth-sun-moon
What is one of the reasons the sun does not keep mean solar time?''
The earth spins at different speeds during different parts of the year.
Don't be silly, the sun doesn't even have a watch.
Because of earth's 23.4 degree tilt the sun's motion does not project uniformly on the celestial equator.
The earth's orbit is elliptical and therefore its orbital speed varies slightly.
Which astronomer of antiquity measured the size of the earth?
Eratosthenes
Aristarchus
Ptolemy
Copernicus
Which astronomer of antiquity made elaborate models of an earth-centered universe?
Aristarchus
Ptolemy
Copernicus
Tycho Brahe
Which astronomer of antiquity first applied a telescope to astronomical observation?
Ptolemy
Copernicus
Tycho Brahe
Galileo Galilei
The formula F=ma is
Kepler's third law.
Newton's first law.
Newton's second law.
a formula used by Galileo.
Seasons are caused by the earth's orbital motion and
tropics and circles.
earth's axial tilt.
a variable sun.
precession of the equinoxes.
Where on earth do you have to be in order to see the south celestial pole directly overhead?
North pole
Tropic of Cancer
Equator
South Pole
When is the next leap year? (Do not use the Julian calendar.)
2018
2019
2020
2024
Why isn't there a lunar eclipse every full moon and a solar eclipse every new moon?
What are degrees, arcminutes, and arcseconds (and how many of which fit into what)?
Sketch an ellipse below. Label at least four parts important for the geometry of an ellipse.
Sketch an outer planet (Mars, for example) and its orbit(s) in two different cosmological models. On the left sketch Mars's orbit(s) as envisioned by Ptolemy, on the right as envisioned by Copernicus.
Make a sketch illustrating why we have seasons.

# Light and Telescopes

Who first used the telescope to look at planets?
Who invented the reflecting telescope?
How is the energy carried by one photon related to the wavelength of light carried by that photon?
How is the temperature of a blackbody related to the wavelength at which most of its light is emitted?
Name the three main types of spectra and give examples for objects that give off the spectra.
List these in the correct order, shortest wavelength first: visible light, ultraviolet, infrared, microwave, gamma rays, radio, X-rays.
An astronomer takes a high resolution spectrum of a nearby star and finds that a spectral line normally seen at 5000 Å appears instead at 5005 Å. This star is
coming toward us.
going away from us.
If the speed of light is 3 × 105 km/s, the velocity of the star in the previous question is
3 km/s.
30 km/s.
300 km/s.
500 km/s.
3000 km/s.

# Inner Planets

What causes the aurora borealis (and aurora australis)?
Plate tectonics is important in shaping the surface of
Earth
Venus
Moon
Mars
Hot-spot volcanism created truly gargantuan mountains on
Earth
Venus
Moon
Mars
The oldest surface'' award goes to
Earth
Venus
Moon
Mars
The largest greenhouse effect'' award goes to
Earth
Venus
Moon
Mars
Mercury's orbital period is very close to 1/4 that of earth. Does that imply that Mercury is located at 1/4 A.U.?
yes
no
After a sun-drenched day Joe Beachcomber watches a crystalline tropical sunset and notices (1) there are neap tides, and (2) he doesn't see any moon in the sky. The phase of the moon is
new
first quarter
full
last quarter
The planets' paths in the sky stay quite close to
the celestial equator
the ecliptic
the line of nodes
the vernal equinox
The fact that the plane of the moon's orbit is much closer to the ecliptic than to the earth's equatorial plane argues most strongly against which of these lunar formation scenarios?
fission
cocreation
capture
collision
The fact that the moon's density and isotopic composition closely resembles the mantle layers of earth favors which lunar formation scenario?
cocreation
capture
collision
Which method for making an atmosphere is almost certainly not important, at least for Venus and the earth?
Early accretion of icy bodies
Solar nebula
Solar wind
Late comet and asteroid impacts
Which structural layer of earth is liquid?
inner core
outer core
mantle
crust
Radar is nifty because information on the following is available, even through clouds:
distance and angular size
a unique spectral signature of the composition
distance and velocity
If interstellar miners removed half of the mass of the moon, by what factor would the moon-earth gravitational force change?
1/4
1/2
no change
2
By counting craters we know that lunar _________ are older.
maria
highlands
Sketch the geometry of the orbit of Mars, labeling at least 3 geometrical features and indicating the position of the sun. It is OK to exaggerate the eccentricity of the orbit to show the parts more clearly.
Why is CO2 missing from Earth's atmosphere?
Why is H2O missing from Venus's atmosphere?

# Outer Planets

Laplace's original nebular hypothesis'' for the formation of the solar system had a difficult time starting the gravitational accretion process by which planets form. Today's version of this theory incorporates what feature that bridges the gap between no clumping of matter and clumps large enough to have noticeable gravity?
very massive gas molecules
mini black holes
sticky dust particles
comets and asteroids
Which is not a point of difference between terrestrial and jovian planets?
distance from the sun
orbital plane
size of atmosphere
total mass
If interstellar miners removed half of the mass of the moon, by what factor would the moon-earth gravitational force change?
1/4
1/2
no change
2

# Comets, Asteroids, and Meteors

In the absence of perturbations from the gravity of planets, do comets such as Halley's or Hale-Bopp travel on elliptical orbits?
yes
no

# The Sun

The part of the sun that we normally see is called the
atmosphere.
chromosphere.
photosphere.
corona.
A complete magnetic solar cycle takes
5.5 years.
11 years.
22 years.
44 years.
The sun gets its energy from
core hydrogen fusion.
shell hydrogen fusion.
core helium fusion.
latent heat.
begin A Joule is the amount of energy a 1-Watt light bulb gives off in one second (the standard units for the meter-kilogram-second system of units that we have been using). How much energy would be produced by the total conversion of 1 kg of material into energy? (For your information, the sun converts this much mass to energy in less than a billionth of a second!)
9 × 1016 Joules
9 × 1013 Joules
9 × 1010 Joules
3 × 105 Joules

# Stars

Which of the following is about the size of the earth?
a black hole from a 20 M star.
a neutron star.
a white dwarf.
a pulsar.
The element iron came from
the Big Bang.
fusion in stars like the sun.
fusion in massive stars.
dust and gas in the Milky Way.
The element hydrogen came from
the Big Bang.
fusion in stars like the sun.
fusion in massive stars.
dust and gas in the Milky Way.
Cepheid variable stars are important distance indicators because (1) they are supergiants and thus visible for many Mpc, well into the realm of galaxies, and (2)
measurement of the apparent magnitude gives the pulsation period of the star.
measurement of the period of pulsation gives the size of the star.
measurement of the period of pulsation gives the apparent magnitude of the star.
measurement of the period of pulsation gives the absolute magnitude of the star.
An H II region usually appears red in color because
interstellar dust both extincts and reddens light.
the red H alpha line from recombining hydrogen is very strong.
blue light is scattered from dust clouds, while red light gets through unattenuated.
it is very cool.
Which could not be plotted on the $x$ axis of the H-R diagram?
color
spectral type
magnitude
temperature
Which could not be plotted on the $y$ axis of the H-R diagram?
absolute magnitude
luminosity
apparent magnitude
Consider a cold gas cloud that collapses under its own gravity. By rare coincidence, it has no net spin at all. Will this cloud collapse to a disk shape?
yes.
no.
How distant is a star that has an astronomical parallax of 1/20th of an arcsecond?
1/2 pc.
20 pc.
200 pc.
50 pc.
Open cluster NGC 6791 has a distance modulus m - M = 10 magnitudes. Therefore, at, say, spectral type G, the stars in NGC 6791 are 100 × 100 = 10000 times dimmer than a G star at 10 parsecs. Using either the inverse square law or the distance modulus formula, what is the distance to NGC 6791?
100000 pc.
100 pc.
1000 pc.
10000 pc.
List the spectral types, hottest first.
Regarding planetary nebulae: What is the mass of the star from which the P.N. formed? What does the central star become after a few tens of thousands of years?
Regarding supernovae: What is the mass of the star that caused the S.N.? What possible stellar remnants are left after the explosion?
Describe the reason why the sun will eventually leave the main sequence, and how the location of fusion changes as it climbs'' the red giant branch.

# Galaxies

For each of the next 5 questions, choose either (a) disk, or (b) spheroid, and write a'' or b'' next to the number.
Where am I likely to find globular clusters?
Where am I likely to find H II regions?
Which appears yellow to red in color, if I see it from a distance?
In which do I need to worry about interstellar extinction?
Where am I likely to find open clusters?
The spiral arms of a galaxy appear blue because of
the presence of interstellar dust clouds.
the presence of many H II regions.
the presence of many globular clusters.
the presence of young stars.
Which galaxy type is basically all spheroid?
Barred spiral.
Spiral.
Irregular.
Elliptical.
                Slide Identifications
(Recognize pictures of the following objects.)

(a) spiral galaxy (unbarred)   (e) dark cloud
(b) barred spiral galaxy       (f) H II region
(c) irregular galaxy           (g) reflection nebula
(d) elliptical galaxy          (h) Bok globule


# Cosmology

Tell how we can have (1) a universe with no center and (2) every galaxy receeding from {\it the Milky Way} as if we {\it were} the center of the expansion.
Write the formula, due to Hubble, that describes the expansion of the universe.
If H0 = 50 km/s/Mpc, what is the approximate distance of a galaxy observed to have a redshift of 5000 km/s?
250 Mpc
100 Mpc
25 Mpc
10 Mpc
If the universe has less than the critical density of matter, we live in
an open universe.
a closed universe.