Notice: The first test this year will have 30 multiple-choice questions and 10 short-answer questions, rather than 40 multiple-choice ones, and you will not need a scantron card; Also, that time we had not covered matter, light and telescopes yet. For the version with the correct answers indicated, click here.

University of Mississippi
ASTR 103 Sections 09-12, Fall 2003

Test 1

Mark your choice of answer for each question on your scantron card. When you are finished, make sure that your name and the test number and version are written on the scantron card. Once you have handed in the scantron card and the instructor has checked your test version, you can take this test with you.

(1) Which one of these planets cannot be seen with the naked eye?
a. Mercury.
b. Venus.
c. Saturn.
d. Neptune.

(2) If you looked at the sky from the Space Station, outside the Earth's atmosphere, which objects would twinkle?
a. Stars
b. Planets.
c. Asteroids and comets.
d. None of the above.

(3) What is the Sun?
a. The biggest and brightest planet in the solar system.
b. The brightest object of the universe, center of all motions.
c. A star like many others, but the only one that is close to us.
d. A star that is larger than all the others in our galaxy.

(4) What is the zenith?
a. The time at which the Moon is highest in the sky.
b. The point straight above us on the celestial sphere.
c. The line along which the Sun moves on the celestial sphere.
d. A small circle on which a planet moves according to the geocentric model.

(5) Approximately how many stars can we see with the naked eye, in good viewing conditions?
a. A few hundred.
b. A few thousand.
c. About 1 million.
d. About 100 billion.

(6) What is a galaxy?
a. A fuzzy, dusty region that sometimes surrounds a very distant star.
b. A place where thousands of icy objects such as comets collect, beyond Pluto.
c. A collection of billions of stars and other matter held together by gravity.
d. A huge cloud of gas suspended in space between the stars.

(7) What is right ascension?
a. The maximum height along a planet's orbit, with respect to the ecliptic.
b. The longitude of the point on the Earth where a telescope is located.
c. A coordinate on the celestial sphere that is a star's equivalent to longitude.
d. The tilt angle between the Moon's orbit and the Earth's orbit.

(8) Where is Polaris located?
a. On the celestial equator.
b. Near the celestial North Pole.
c. On the ecliptic.
d. Near the zenith.

(9) The path that the Sun seems to follow among the stars is called
a. Celestial equator.
b. Equinox.
c. Parallax.
d. Ecliptic.

(10) Do stars move?
a. They move in our local sky because the Earth rotates, but on the celestial sphere they essentially don't.
b. They move from East to West in our local sky, and from West to East on the celestial sphere.
c. Yes, their motion depends on where they are along their orbit; right now they are in retrograde motion.
d. No, stars are always in the same position in the sky; only planets, the Moon and the Sun move.

(11) What do we mean when we talk about Mars' retrograde motion?
a. Mars spins backward around its axis, compared to all other planets.
b. During part of its orbit, Mars appears to move backward on the celestial sphere.
c. Mars always moves in the sky in the opposite direction to all other planets.
d. It is gradually moving away from the Sun, in an orbit that spirals slowly outward.

(12) What do we mean by the Earth's rotation?
a. Its motion around the Sun over the course of a year.
b. The rotational motion around its axis over the course of a day.
c. Its wobbling motion over a period of many years.
d. The fact that the appearance of the sky changes every day.

(13) Is there a difference between a solar and a sidereal day?
a. A sidereal day is a little longer.
b. A solar day is a little longer.
c. The sidereal day refers to a planet orbiting another star.
d. No, they are two names for the same thing.

(14) What kind of day is the one our clocks measure to be 24 hours long?
a. A lunar day.
b. A solar day.
c. A sidereal day.
d. A Ptolemaic day.

(15) What do we mean by the Earth's revolution?
a. Its motion around the Sun over the course of a year.
b. The rotational motion around its axis over the course of a day.
c. Its wobbling motion over a period of many years.
d. The fact that the appearance of the sky changes every day.

(16) What are solstices?
a. The days when day and night are equally long.
b. The longest and shortest days of the year.
c. The occasional alignments of the Earth, Moon and Sun.
d. The paths that the planets followed according to old models.

(17) What is meant by the precession of the Earth?
a. The wobbling of the Earth's rotation axis over many thousands of years.
b. The seasonal change of the constellations in the Earth's night sky.
c. A method by which its distance from the Sun is calculated using parallax.
d. The passage of the Earth along the line joining the Sun and the Moon.

(18) Why do we see different phases of the Moon on different days?
a. Because the Moon changes shape, it is not always round.
b. Because the Moon rotates in such a way that we don't always see the same side.
c. Because the Sun illuminates a larger or smaller portion of the Moon's surface.
d. Because we usually don't see the whole half of the Moon that is illuminated.

(19) Suppose that the Moon is full today. How long will it be until the next full Moon?
a. The length of time varies, sometimes it may take years.
b. 7 days.
c. 23 hours and 56 minutes.
d. About 29 days.

(20) Around what time will a full Moon rise above the horizon?
a. Noon.
b. Sunset.
c. Midnight.
d. The answer depends on the time of year.

(21) What causes a solar eclipse to occur?
a. The Moon passing through the Earth's shadow.
b. The Earth passing between the Moon and the Sun.
c. The Moon passing between the Earth and the Sun.
d. The Sun passing between the Earth and the Moon.

(22) When a solar eclipse occurs, what phase does the Moon have to be in?
a. New moon.
b. First (waxing) quarter.
c. Full moon.
d. It can be in any phase.

(23) Why don't we see lunar and solar eclipses every month?
a. Because the weather does not always allow us to see them.
b. Because the Moon's orbit is not in the plane of the Earth's orbit.
c. Because the Earth's axis is tilted with respect to its orbit.
d. Because usually we are facing a different direction when they occur.

(24) How can we use astronomy to find out when seasons will change?
a. By keeping track of the dates when eclipses occur.
b. By keeping track of where the Sun and stars rise and set.
c. By keeping track of the location of planets in the sky.
d. By keeping track of the phase the Moon is in.

(25) Which ancient people first emphasized the need for developing models to explain astronomical observations?
a. The Mesopotamians.
b. The Egyptians.
c. The Greeks.
d. The Chinese.

(26) Which planets were already known by the 1600's?
a. Venus, Mars, Jupiter and Saturn.
b. Mercury, Venus, Mars, Jupiter and Saturn.
c. Venus, Mars, Jupiter, Saturn, Uranus and Neptune.
d. Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune.

(27) Which of the following is a reason why ancient astronomers believed in a geocentric model?
a. At that time, it was not possible to observe the stars' parallax.
b. The stars show a very obvious parallax displacement.
c. The retrograde motion of planets is explained best by geocentric models.
d. The geocentric model agreed with Copernicus' ideas.

(28) What is the main assumption in a heliocentric model?
a. The Earth is the center of the universe and all objects revolve around it.
b. The Earth and other planets in the solar system revolve around the Sun.
c. The center of the Earth is as hot as the surface of the Sun.
d. The space between the planets in the solar system is filled with helium.

(29) What is an epicycle?
a. A full cycle of seasons on Earth due to the tilt of its rotation axis.
b. A smaller circle added to a planet's main circular orbit in old models.
c. The center of the circle along which a planet moves around the Sun.
d. The point in the sky at which a planet reverses its direction of motion.

(30) Around what time was the currently accepted model for the solar system developed?
a. 300-200 BC.
b. 100-200 AD.
c. In the 1500-1600's.
d. Around the year 1924.

(31) What kind of telescope did Tycho Brahe use?
a. He did not have a telescope.
b. A refracting telescope.
c. A reflecting telescope.
d. A diffracting telescope.

(32) How was Tycho able to establish that comets were more distant than the Moon?
a. He measured the time it takes a comet to complete a full orbit.
b. He found the parallax of a comet as seen from different places on Earth.
c. He measured the apparent size of a comet, as seen through a telescope.
d. He applied Newton's laws and found the force of gravity on a comet.

(33) Why is Kepler important in the history of astronomy?
a. He made excellent observations of the planets' positions.
b. He discovered how the Earth and other planets move around the Sun.
c. He explained the way the planets move in terms of gravity.
d. He was the first person who used a telescope in astronomy.

(34) How are ellipses related to the orbit of a planet?
a. The planet is at one focus, the Sun at the other one.
b. The Sun is at one focus, the planet moves along the ellipse.
c. The Sun is at the center, the planet moves along the ellipse.
d. The planet and the Sun are at opposite points of the ellipse.

(35) Does the speed of a planet along its orbit vary?
a. Yes, it moves fastest when it is closest to the Sun.
b. Yes, it moves fastest when it is farthest to the Sun.
c. Yes, it moves fastest when it is moving toward the Sun.
d. No, each planet always moves at the same speed.

(36) Which of the following aspects of the Solar System is not addressed by Kepler's laws?
a. The fact that the planets' orbits are not shaped like circles.
b. The part of their orbit during which planets move fastest.
c. The fact that the planets' orbits all lie approximately in the same plane.
d. The relationship between the periods of revolution of different planets.

(37) What important fact did Galileo observe about Jupiter with his telescope?
a. That it has its own moons revolving around it.
b. That it does not revolve around the Earth.
c. That there are imperfections, dark spots on its surface.
d. That it goes through phases like the Moon.

(38) Why does an airplane need an engine to keep flying, while the Moon stays up without an engine?
a. Because the Moon is pushed along its orbit by the gravitational force.
b. Because the Moon is pushed along its orbit by a magnetic force.
c. Because the airplane is inside the atmosphere and would be slowed down by friction.
d. Because the airplane is a much smaller and lighter object than the Moon.

(39) Newton's law of gravitation states that gravity between two objects
a. Gets weaker if the objects' motion is made to slow down.
b. Gets weaker if the separation between the objects increases.
c. Exists only if the objects' temperature is high enough.
d. Exists only if one of the objects is a star or a planet.

(40) What causes high and low tides along the coasts of Earth's oceans?
a. The Earth's revolution around the Sun.
b. The precession of the Earth's axis.
c. The gravitational attraction by the Moon.
d. The apparent retrograde motion of Mars.