Notice: The first test this year will have 30 multiple-choice questions and 10 short-answer questions, rather than 50 multiple-choice ones, and you will not need a scantron card; Also, that time we had not covered telescopes yet. For the version with the correct answers indicated, click here.

University of Mississippi
ASTR 103, August 2006 Minisession

Midterm Test

Mark your choice of answer for each question on your scantron card. When you are finished, make sure that your name is written on the scantron card. Once you have handed in the scantron card, you can take this test with you (you may want to check your answers later).

(1) Why is the daytime sky blue?
a. Because we are facing a part of space that is bluer than the rest.
b. Because the Earth is warmer than at night and emits blue light.
c. Because the Sun is up and illuminates the space between planets and stars.
d. Because blue sunlight is scattered all around us by the Earth's atmosphere.

(2) 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.

(3) Is the Sun different from the other stars in the sky?
a. Yes, it is much brighter and bigger in size.
b. Yes, it is the only yellow star, the others are blue or red.
c. Yes, it is the only one that has planets around it.
d. No, the only difference is that it is much closer to us.

(4) Which of the following statements about planets and stars is correct?
a. Stars appear brighter in the sky than all planets because they are much larger.
b. Planets appear brighter in the sky than all stars because they are much closer.
c. Planets look smaller than stars when viewed through a telescope.
d. Planets move on the celestial sphere over time, stars basically don't.

(5) Which is these statements about the planet Venus is correct?
a. It is always close to the Moon in the sky.
b. It is always close to the Sun in the sky.
c. It can only be seen late at night when the sky is very dark.
d. It is the slowest moving planet on the Celestial Sphere.

(6) What is the celestial sphere?
a. An imaginary surface around the Earth used for locating stars and planets.
b. A sphere surrounding the Sun, on which the Earth and planets move.
c. The blue globe of the Earth, as it appears when viewed from space.
d. A sphere that separates the stars in our galaxy from other ones.

(7) What is declination?
a. The latitude of the point on the Earth where a telescope is located.
b. The angle at which an object is located above or below the Celestial Equator.
c. The downward motion of a star as it sets below the horizon.
d. The tilt angle between the Moon's orbit and the Earth's orbit.

(8) What is the name of the star at the North celestial pole?
a. Polaris.
b. Betelgeuse.
c. Sirius.
d. Alpha Centauri.

(9) Why do stars move across the sky overhead through the night?
a. Because the stars revolve around the Earth.
b. Because the Earth revolves around the stars.
c. Because the stars rotate around their axis.
d. Because the Earth rotates around its axis.

(10) What is the ecliptic?
a. The time at which an eclipse will occur.
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.

(11) How many constellations do we officially recognize in the sky?
a. 12.
b. 88.
c. About 150,000.
d. About 100 billion.

(12) What is the Zodiac?
a. The set of constellations that are located along the celestial equator.
b. The set of constellations that are located along the ecliptic.
c. The point straight above our head in the sky at a given time.
d. The point on the celestial sphere above the Earth's north pole.

(13) If someone tells you that one night they saw Mars rise in the West and set in the East, you can conclude that
a. Mars is an a period of retrograde motion.
b. That person was looking at Mars from the Southern hemisphere.
c. Mars is in a period of normal, prograde motion.
d. That person was either mistaken or was lying.

(14) Why is there a difference between a solar and a sidereal day?
a. Because the Earth is rotating around its axis.
b. Because in one day the Earth moves a little along its orbit around the Sun.
c. Because the celestial sphere rotates around the Earth.
d. Because in one day the stars' positions change slightly.

(15) 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.

(16) What are seasons on Earth due to?
a. Changes in the distance between the Sun and Earth.
b. The tilt of the Earth's axis with respect to its orbit.
c. The influence of the Moon on the Earth's motion.
d. The location of the other planets in the solar system.

(17) The day of the year in which the Sun is lowest in the sky is called
a. Vernal (Spring) equinox.
b. Autumnal (Fall) equinox.
c. Summer solstice.
d. Winter solstice.

(18) Is the Summer solstice the hottest day of the year?
a. Yes, because that is when the Sun is highest in the sky.
b. No, the hottest days are a little earlier.
c. No, the hottest days are a little later.
d. No, the Spring equinox is the hottest day.

(19) What is parallax?
a. The apparent displacement of an object when the observation point changes.
b. A situation in which the Earth's axis and the Moon's axis are parallel.
c. A method for measuring the angular size of an object.
d. A method for aligning a telescope with the Earth's axis.

(20) When do we say that the Moon is "new"?
a. When it is at the peak of its brightness.
b. When it is at the point on its orbit that is closest to Earth.
c. When it cannot be seen because it is between us and the Sun.
d. When it has just come out from a thick layer of clouds.

(21) Why do we say that the Moon is in "first quarter" when we see half of the disk?
a. Because at that time only one fourth of the Moon is illuminated by the Sun.
b. Because at that time it has gone through one fourth of its monthly cycle.
c. Because "quarter" is just another word for "phase" of the Moon.
d. Because of an old historical misconception about the phases of the Moon.

(22) On a day when the Moon is full, at what time is it highest in the sky?
a. At sunset.
b. Around midnight.
c. In the early morning.
d. It may occur at different times, depending on the seasons.

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

(24) When a lunar eclipse occurs, what phase does the Moon have to be in?
a. It could be any phase, depending on the time of day when it happens.
b. First quarter.
c. New Moon.
d. Full Moon.

(25) What causes a solar eclipse to be annular rather than total?
a. The Earth's tilt bringing us closer to the Sun in Summer.
b. The Moon being slightly further away, so it doesn't cover the whole Sun.
c. The Sun being brighter than usual, so we see it glowing behind the Moon.
d. The viewer being at the wrong location on the Earth's surface.

(26) How long does a total solar eclipse usually last?
a. Less than a second.
b. A few minutes.
c. Almost an hour.
d. Two to three days.

(27) How old are the earliest human-made astronomical structures known?
a. From around 200 BC.
b. From between 3000 and 5000 BC.
c. From between 80,000 and 100,000 years ago.
d. From around 3 million years ago.

(28) Why did prehistoric astronomical sites have circular stone arrangements?
a. To mark directions where astronomical objects rise and set.
b. To indicate places where stars could be seen without light pollution.
c. To keep track of dates when eclipses were predicted to occur.
d. To represent artistically the celestial sphere and the stars' positions.

(29) What is Stonehenge?
a. A cave where paleolitic paintings including stars were found.
b. A place in Wyoming where the Indians built a Medicine Wheel.
c. A circular structure of tall stones in Southern England.
d. A prehistoric era, during which the oldest sites were built.

(30) Where do the names for the seven days of the week come from?
a. Seven important people in the Holy Bible.
b. Seven important people in the Koran.
c. The Sun, Moon, and the planets known in antiquity.
d. The seven visible stars in the Pleiades cluster.

(31) Aristotle concluded that the Earth did not revolve around the Sun because
a. He was following religious teachings.
b. He carefully observed the motion of planets over long times.
c. He could not feel the Earth's motion or see star parallax.
d. He read about Copernicus' and Kepler's work.

(32) 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.

(33) Why is Ptolemy important in the history of Astronomy?
a. He was the first person who observed the stars' parallax.
b. He developed a very detailed and successful geocentric model of the solar system.
c. He was the first person who understood the force of gravity.
d. He made the best observations in astronomy before the telescope was invented.

(34) What is the main contribution to astronomy made by Copernicus?
a. He made excellent observations of the planets' positions.
b. He proposed a modern heliocentric model of the solar system.
c. He explained the orbits of planets in terms of gravity.
d. He was the first person to use a telescope in astronomy.

(35) What was important about Tycho's observation of a comet in the 1500's?
a. It was the first time ever a comet was recorded.
b. It showed that distant objects, beyond the Moon, can change.
c. It was evidence in support of a heliocentric model.
d. It showed how good the telescopes he used were.

(36) Who is recognized as the first person to realize that the orbits of planets are not based on circles?
a. Ptolemy.
b. Copernicus.
c. Tycho.
d. Kepler.

(37) 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.

(38) Why was Galileo's observation of the Sun important?
a. Because he saw that the Sun does not move.
b. Because he was able to show that the Sun is a star.
c. Because he calculated the Sun's size for the first time.
d. Because he showed that the Sun is not a perfect sphere.

(39) What does an object do if no force is acting on it?
a. It either doesn't move, or moves along a straight line at constant speed.
b. If either doesn't move, or slows down and eventually comes to a stop.
c. It falls straight down.
d. It cannot move at all.

(40) When gravity makes a ball fall toward the Earth, does the Earth also feel attracted toward the ball?
a. No, the Earth only produces gravity, it is not subject to it.
b. No, the Earth is only subject to the gravity of larger bodies like the Sun.
c. Yes, it feels the same force and moves towards the ball by the same distance.
d. Yes, it feels the force, but it is hardly affected because of its huge mass.

(41) What happens to the mass and weight of astronauts orbiting the Earth inside a space shuttle?
a. Their weight becomes zero.
b. They feel weightless because they are in free fall.
c. Their mass becomes zero.
d. Both their mass and their weight are zero in space.

(42) Do all objects exert a gravitational pull on other objects?
a. No, some exert a gravitational push, others a pull.
b. No, only more massive objects can pull on lighter ones.
c. No, only the Sun, the Earth, and other celestial objects do.
d. Yes.

(43) Do planets really orbit the Sun along ellipses?
a. No, they follow small circles on top of big circles, and the result just appears to be an ellipse.
b. No, in reality only the Sun moves along an ellipse.
c. Almost, but their orbits are slightly perturbed by additional forces from objects other than the Sun.
d. Yes, because that is what Kepler's laws tell us.

(44) Can you apply Kepler's laws to the orbits of moons around a planet?
a. Yes, because the force involved is still the force of gravity.
b. Yes, but only because the planet is orbiting the Sun at the same time.
c. No, because Kepler wrote down his laws only for planets.
d. No, because moons are too small.

(45) What allowed Newton to add a few details that were not in Kepler's laws of planet motion?
a. Newton had better data available on the positions of planets.
b. Newton made predictions based on his understanding of general laws.
c. Newton realized that Kepler had made a few calculational errors.
d. Newton knew what the planets and the Sun were made of.

(46) Which one of the following is larger?
a. A molecule.
b. An atom.
c. An electron.
d. A proton.

(47) How many protons does a helium atom have?
a. 0.
b. 1.
c. 2.
d. 4.

(48) What are ions?
a. Small particles contained inside the nuclei of atoms.
b. Atoms with missing electrons, or extra electrons.
c. Individual packets of radio waves, similar to photons for light.
d. Particles that have not yet been identified.

(49) What makes the particles inside an atom's nucleus stick together?
a. Electric forces between particles of opposite charges.
b. Nuclear forces, which are stronger than the electric ones.
c. Weight pulls them inward, because those particles are very massive.
d. The electrons orbiting around the nucleus keep them tightly bound.

(50) Which of the following is not a way for heat to travel from one place to another?
a. Radiation.
b. Refraction.
c. Conduction.
d. Convection.