ASTRONOMY 101

1. What is the main mechanism by which the lower atmosphere of Earth is heated? a. Sunlight heats Earth's surface and the resultant heat is transferred to the atmosphere by infrared radiation and convective gas motions. b. Conduction carries heat from Earth's interior to the surface where conduction in the lower atmosphere transfers this heat to the higher layers. c. friction between the winds in the atmosphere and the mountain ranges and land masses of Earth d. absorption of sunlight by molecules of the gases of the atmosphere.

2. The greenhouse effect heats a planet because a. more sunlight gets in. b. the albedo is increased. c. infrared radiation is trapped. d. the atmosphere becomes ionized.

3. "Chemical differentiation" in planetary sciences refers to a. the formation of rocky planets in the hotter, inner solar system and gas giants in the colder, outer regions. b. the circulation of iron in the core of a planet, resulting in the generation of a magnetic field. c. the large-scale convection of rock in the mantle of a planet, that on Earth causes continental drift. d. the sinking of heavier elements toward the center of a planet and the floating of lighter elements toward the surface.

4. What is the basic structure of Earth's interior (from the center out)? a. solid iron inner core, molten iron outer core, rocky mantle, lighter rocky crust b. molten iron inner core, molten rocky outer core, solid rocky mantle, lighter rocky crust c. molten iron core, molten rocky mantle, solid rocky crust d. molten iron inner core, solid iron outer core, rocky mantle, lighter rocky crust

5. You are a geologist detecting S (secondary) seismic waves from a source somewhere else on Earth. You know that these S waves a. have traveled in a straight line through Earth from the source to your detector. b. have not passed through the core of Earth because they can't propagate through liquids c. have traveled along the surface of Earth from the source to your detector. d. must have originated only a few hundred miles away because S waves tend to attenuate quickly within Earth.

6. The average speed of motion of the plates on Earth's surface is a. very small, less than an inch per millenia. b. a few feet per year c. about an inch per year d. about an inch per century

7. The San Andreas fault in California is an example of a. an upthrust due to a hot spot in Earth's mantle. b. a subduction zone, where one plate is pushed back down into Earth. c. a spreading center, where two tectonic plates are being pushed away from each other. d. two tectonic plates sliding past each other.

8. The presence of oxygen in Earth's atmosphere is thought to result directly from what type of process? a.volcanic eruptions b. original condensation of interplanetary gas clouds c.outgassing of the oceans d. biological activity

9. In the stratosphere, the temperature increases as you go higher. The cause of this is a. heating by auroral activity higher in the atmosphere. b. absorption of ultraviolet radiation by ozone, O3. c. ionization of O2 and N2 by solar ultraviolet radiation. d. turbulence and friction caused by wind and weather.

10. The lunar maria appear smooth because they are a. ancient sea beds, now dry, dating back to when the Moon had a denser atmosphere and rainfall was abundant. b. very recent lava flows, which have obliterated earlier craters. c. regions where craters have been obliterated by crustal deformation caused by hot spots and volcanic lava flow from the underlying molten mantle. d. ancient lava flows that occurred soon after the end of an early period of intense bombardment and have had relatively few impacts since then.

Mercury is much closer than Venus to the Sun, and yet it never appears brighter than Venus, even when both are at maximum brightness, because Select one: a . Mercury is small, has a dark surface, and has no reflecting clouds. b. Mercury is larger than Venus, but it has a thick atmosphere which impedes reflection from its surface, making it appear dark. c .we never see more of Mercury than a thin crescent because of its orbital path relative to that of Earth. d. Mercury has average reflectivity but is very small and hence appears relatively dark.

In view of Mars's tilted angle of rotation at 25° to the ecliptic, its very similar rotation period to that of Earth (24 hours, 37 minutes), and its orbital period of nearly 2 years, what will be the seasonal variations on Mars, compared to those upon Earth? Select one: a. very similar seasonal variations, including seasons lasting about as long as those upon Earth because of the similar rotation rates of the two planets b. much smaller seasonal variations than Earth's seasonal variations because of Mars's distance from the Sun, each season lasting about twice as long as those upon Earth c. very similar seasonal variations, but each season lasting about half as long as those upon Earth because of the different orbital periods d. very similar seasonal variations, but with each season lasting twice as long as Earth's seasons

The surface and near-surface atmospheric conditions on Venus are Select one: a. CO2 atmosphere, high pressure, and high temperature. b. no atmosphere, very variable temperature. c. dense methane, ammonia, and H2O atmosphere, low temperature. d. CO2 atmosphere, low pressure, and low temperature.

In what way was the production of the Hawaiian Islands on Earth similar to the production of some of the major mountains on Mars and Venus? Select one: a.They were produced by slow buildup of coral reefs in ancient oceans. b.They were produced by impacts of massive asteroids during the ancient heavy bombardment period, and are now being eroded by wind and water. c.They were produced by hot-spot volcanism and upflow of heat from below. d.They were formed by upthrust from collisions of two tectonic plates.

Mars has a crust which is everywhere thicker than Earth's crust. What is the primary reason for this? Select one: a. Mars rotates too slowly to allow the crust to remain fluid. b. Mars rotates too rapidly to allow the crust to remain fluid. c. Mars is cooler because it is farther from the Sun. d. Mars, being smaller, cooled more rapidly.

How did the inner planets, Venus and Earth, acquire their original atmospheres? Select one: a. the impact and melting of icy comets and asteroids from the planetary system and perhaps beyond b. capture of solar wind gases from the Sun as they stream past the planets c.outgassing of the planets through volcanoes and other vents d.gravitational capture of material from the original solar nebula by the planets

The Mars Exploration Rovers were both landed at locations which seemed promising for uncovering evidence of ancient water flow on Mars. What did they find? Select one: a. Neither rover discovered any signs that water had ever existed on the surface of Mars. b. As expected, both found sedimentary rocks, evaporites, and hematite, all signs of abundant water on the Martian surface in the past. c. Spirit found abundant signs, including pools of liquid water, that water exists at present on the Martian surface, while Opportunity found none. d. Spirit found few signs of past water flow but Opportunity found sedimentary rocks, evaporites, and hematite, all signs of abundant water on the Martian surface in the past.

In what important way does the Jupiter-moon system resemble a miniature Solar System, perhaps providing a hint to the initial formation of both systems? Select one: a. Average density of objects decreases as distance increases from the central object, because the heat from this object would have melted and evaporated the volatile low-density ices from the closer objects. b. Average density of objects increases the farther away they are from the central object, because this central object can attract high-density material over a greater range of distances than for low-density material. c. The masses of objects increase as distance increases from the central object, because the probability of accretion of small objects into larger objects increases with distance. d. The reflectivity of their surfaces decreases, the farther away they are from the central object, because the nearer objects have thicker clouds around them.

What characteristic of Jupiter's moon Io makes it different from any other known satellite in the Solar System? Select one: a. It has a permanent, dense atmosphere which totally obscures the solid surface. b. Its surface shows uncratered, flooded regions (now frozen) and other signs of geologically recent activity involving water. c. It has geyser-like plumes of nitrogen gas. d. It is volcanically active.

What property is shared by the Earth and Europa, one of Jupiter's large moons? Select one: a. They have both been shown to harbor life in their oceans. b. Both have warm oceans of water. c. They are about the same physical size. d. They both have thick atmospheres of nitrogen and oxygen.

1. At the present time, how many extra-solar planets have had confirmed discoveries? A.None B.Less than 500 C.Between 500 and 1000 D.More than 1000

2. In general, what are the characteristics of the vast majority of planets that have been found so far around other stars? A.They are the mass of Saturn or larger, and are therefore Jovian-type planets. B.They are larger than the mass of Jupiter, and are probably a new type of planetary object. C.between the mass of Mercury and Earth, and are therefore terrestrial-type planets. D.They have masses between the mass of Earth and about three times the mass of Jupiter.

3. Assuming that the transit curves shown belong to two exoplanets orbiting the same star. What is necessarily true? A. Planet on the left plot has a smaller mass B. Planet on the right plot is bigger C. Planet on the left plot is closer to the star D. None of the above

4. What was the first big surprise related to exoplanets A.That exoplanets exist at all B.That exoplanets can be way bigger than Jupiter C.That planets like Jupiter can be really close to their parent star D.That Earth-like planets are so hard to detect

5. What of the following is not true about the radial velocity method? A. The more massive the planet, the easier it is to detect B. It can be used to measure the inclination of the planet's orbit with respect to the observer (actually, that is one of the main problems, that you don't know the inclination). C. The Doppler shift of the star is used to measure the star's wobbling motion D. It was the first method that led to the regular discovery of exoplanets

6. At the present time, the energy of the Sun is generated A. in its central core only, by fission of heavy nuclei. B. by the release of gravitational energy as the Sun slowly shrinks. C. in the central core by fusion of helium nuclei and in an outer shell by fusion of hydrogen nuclei. D. in its central core only, by fusion of hydrogen nuclei.

7. What happens to the neutrinos produced by the nuclear reactions in the core of the Sun? A. They collide and stick together with protons to form helium nuclei. B. They escape quickly from the Sun into space. C. They combine with protons to form neutrons. D. They collide with electrons, producing energy.

8. In order from lowest to highest, what are the names of the three layers in the Sun's atmosphere? A. photosphere, chromosphere, corona B. chromosphere, photosphere, corona C. corona, chromosphere, photosphere D. photosphere, corona, chromosphere

9. The rotation of the Sun is A. fastest at the equator, slowest at mid-latitudes, rising to intermediate speeds near the poles. B. fastest at mid-latitudes, slower at the equator, and slowest near the poles. C. fastest at the equator, slower at mid-latitudes, and slowest near the poles. D. slowest at the equator, faster at mid-latitudes, and fastest near the poles.

10. Sunspots appear dark because they A. are coronal holes. B. are cooler than the surrounding surface. C. are regions from which the light is prevented from escaping by strong magnetic fields. D. have a different chemical composition than the surrounding surface.

11. (Bonus) What astronomical event is happening this weekend? A. A lunar eclipse on May 19 B. A lunar eclipse on May 20 C. A solar eclipse on May 19 D. A solar eclipse on May 20

1. The correct sequence of planets in our solar system from the Sun outward is A) Mercury, Venus, Earth, Mars, Saturn, Uranus, Jupiter, Neptune. B) Mercury, Earth, Venus, Mars, Jupiter, Saturn, Uranus, Neptune. C) Mercury, Venus, Mars, Earth, Jupiter, Saturn, Uranus, Neptune. D) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

2. In our solar system, which of the following planets is not a member of the Jovian group? A) Mars B) Saturn C) Neptune D) Jupiter

3. The low average densities of the Jovian planets, which have high masses and hence high gravitational fields, is an indication that their interiors are A) gaseous and rocky B) composed mainly of very light elements, such as H and He. C) composed of very porous rock (many small, empty cavities). D) composed of H2O, CH4 (methane), and NH3 (ammonia).

4. Which of the following general statements about all of the planets in the planetary system is true? A) They have hard, rocky surfaces, which can be seen and photographed. B) They orbit the Sun in the same direction. C) They have satellites or moons. D) They have very dense atmospheres.

5. A nitrogen molecule (N2) is lighter than a carbon dioxide molecule (CO2). For a mixture of the two gases at a given temperature, the N2 molecules will have a A) greater average speed than the CO2 molecules. B) smaller average speed than the CO2 molecules

6. Comets are typically A) chunks of ice that begin to vaporize if they pass close to the Sun. B) chunks of rock a few tens to hundreds of kilometers in diameter. C) slushy mixtures of liquid and ice. D) gaseous bodies from which some of the gas is pushed out by the Sun to form a long tail.

7. The craters on the Moon are all nearly circular. Why is this? A) Most of the craters on the Moon were formed by volcanoes, and this results in circular craters. B) It is believed that the objects that formed the impact craters on the Moon's surface all struck the Moon approximately perpendicular to its surface, and this would result in circular craters. C) The objects that produced the impact craters came in at a variety of angles, but the craters were actually made by the shock waves generated by impact—and this results in circular craters. D) The objects that produced the impact craters had been rounded by many previous collisions in space, and round objects produce circular craters regardless of their direction of impact.

8. In general, large bodies in the solar system show less evidence of cratering than do small bodies. Why should we expect this correlation? A) The gravity of large bodies deflects incoming projectiles and thus there are fewer collisions. B) Large bodies are more likely to retain an atmosphere, and thus most large projectiles burn up before striking the ground. C) Large bodies actually receive more hits because of their larger size, but later craters obliterate earlier ones, and we only see evidence of the most recent. D) Large bodies cool more slowly and are more likely to retain internal heat and be geologically active, capable of resurfacing the planet and obliterating craters.

9. In general, small bodies in the solar system are less likely than large bodies to possess a planet-wide magnetic field. Why should we expect size and magnetism to be correlated? A) A small body cools more rapidly and is less likely to possess a molten, liquid interior — one requirement for planet- wide magnetism. B) Small bodies are more likely to be heavily cratered, and such impacts can destroy the mechanism that produces the magnetic field. C) Magnetic fields are produced by the entire volume of a body. Smaller bodies have smaller volumes and hence smaller magnetic fields. D) Small bodies necessarily rotate more slowly, and a rapid rotation rate is one requirement for a planet-wide magnetic field.

10. The most abundant elements in the universe, as revealed by spectroscopic analysis, in order of decreasing abundance (number of atoms) are A) nitrogen, oxygen, carbon, helium. B) hydrogen, helium, oxygen, carbon. C) helium, carbon, oxygen, hydrogen. D) hydrogen, iron, oxygen, nitrogen.

11. The composition of matter in the universe can be summarized by which statement? A) About half of the mass of the universe is in the form of rocks, molecules, and planetary material, visible by infrared radiation. B) All but 2% of the mass in the universe is hydrogen and helium. C) 2% of the mass of the universe is hydrogen and helium, the rest is heavier elements. D) All but 2% of the mass of the universe is hydrogen.

12. How has the present mix of chemical elements in the universe been produced? A) All the known elements have been formed by the radioactive breakup of the heavy elements formed in the initial Big Bang. B) All of the known elements were formed in the Big Bang. C) H and He were formed in the Big Bang, while the heavier elements have been slowly forming by collisions in cold interstellar gas clouds. D) H and some He were formed in the Big Bang, while the heavier elements have been slowly formed in the centers of stars and in supernovae over the life of the universe.

13. What was the form of the material from which the solar system formed? A) a nebula made mostly of hydrogen and helium gas, but enriched in heavier elements from supernova explosions B) a nebula made mostly of heavy elements, but enriched in hydrogen and helium from the supernova explosions C) a nebula made entirely of hydrogen and helium gas

14. The most probable time sequence for the solar system's formation was that the A) Sun formed initially, and the planets and major moons were captured much later as they drifted by the Sun. B) planets formed first out of the cold gas and dust nebula, followed by the Sun, which formed when the gas had become much hotter. C) Sun formed first, the planets were spun off from the Sun, and the moons in turn were spun off from the planets. D) Sun contracted first as a gas ball, and the planets and moons formed shortly afterward by accretion and condensation.

15. The manner in which the terrestrial planets formed was A) accretion of planetesimals to form a core, followed by gravitational capture of gas from the solar nebula. B) gravitational condensation of hydrogen, helium, and dust in eddies or vortices in the solar nebula. C) gravitational condensation of gas followed by capture of solid planetesimals. D) accretion of solid planetesimals containing mostly rocky material.

The oldest rocks, as measured by radioactive age-dating, have been found Select one: a.in the lunar highlands. b.on Earth. c.in the maria of the lunar lowlands. d.in meteorites.

Radioactive decay in an atom occurs because Select one: a.the atom has more protons than neutrons. b.the atom has more protons than electrons. c.the nucleus, originally stable, has been made unstable by exposure to the nuclear reactions in a nearby star. d.the nucleus contains a mix of neutrons and protons which is not stable.

What was the form of the material from which the solar system formed? Select one: a. debris from the explosion of a massive star b. a nebula made mostly of heavy elements, but enriched in hydrogen and helium from the supernova explosions c. a nebula made mostly of hydrogen and helium gas, but enriched in heavier elements from supernova explosions d. a nebula made entirely of hydrogen and helium gas

The temperature began to rise at the center of the solar nebula because Select one: a.massive stars nearby were heating the nebula with their ultraviolet radiation. b.the nebula was contracting, increasing the speed of motion of the atoms. c.supernova explosions were stirring up the material there and causing turbulence. d.fusion reactions were beginning in the core, releasing tremendous amounts of heat.

The early phases of planetary formation into protoplanets were characterized by Select one: a.the shattering collision of very large objects into planet-sized fragments. b.condensation of hot gas clouds. c.violent collapse and heating of gas and dust grains by gravity. d.slow accretion of small particles by gravitational attraction and collision.

How are many of the satellites of the Jovian planets thought to have formed? Select one: a.from material thrown off the planet when one or more large planetesimals or small planets collided with it b.from a disk of material around the planet, similarly to the way the planets formed around the Sun c.They are fragments of one large satellite orbiting around each of the planets. d.They are small planets in their own right but were captured by the Jovian planets early in the solar system's history.

Of all the stars with metal abundances like the Sun surveyed so far by the radial velocity method, about how many have planets in orbit around them? Select one: a.much less than 1% b.virtually all of them c.10-20% d.50-60%

In general, what are the characteristics of the planets that have been found so far around other stars? Select one: a.They have masses between the mass of Earth and about three times the mass of Jupiter. b.They are the mass of Saturn or larger, and are therefore Jovian-type planets. c.They are larger than the mass of Jupiter, and are probably a new type of planetary object. d. between the mass of Mercury and Earth, and are therefore terrestrial-type planets.

What is the Sun's energy source? Select one: a.radioactivity b.heat released by gravitational contraction c.thermonuclear fusion in the core d.primordial heat left over from the release of gravitational energy when the Sun first formed

The Sun has existed for a very long time without change in its size, appearance, or behavior. This means that it must be in hydrostatic equilibrium. Under these conditions, which two parameters must be in exact balance within the Sun? Select one: a.hydrogen gas pressure and helium gas pressure b.magnetic field and force of gravity c.numbers of hydrogen and helium nuclei d.inward force of gravity and outward gas pressure

When light passes through a prism of glass, the a) different colors are caused by multiple reflections in the prism and interference between the resulting beams. b) different colors or wavelengths of light are separated in angle by the prism. c) prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors that we see. d) prism adds colors to different parts of the broadly scattered beam coming out of it.

2. Which is the correct reasoning for why a x-ray telescope located in Antarctica that is to be used to look for evidence of black holes in the centers of galaxies should not get funded? A)There is no way to detect the presence of a black hole. B) Only half of the sky can be seen from Antarctica C) You can't build a functioning telescope in Antarctica. D) X-rays don't penetrate Earth's atmosphere.

3. The first reliable method developed to measure the speed of light involved a) careful observation of the eclipses of the moons of Jupiter at different times in Jupiter's orbit. b. observing the opening and closing of shutters on lanterns on hilltops separated by a known distance. c) splitting of light into its spectrum in laboratory experiments. d) making careful measurements of the orbital path of the Moon around Earth.

4. Gamma rays and visible light are a) different because gamma rays are made up of particles, whereas light is made up of waves. b) the same thing except that gamma rays have a smaller frequency than visible light. c) the same thing except that gamma rays have a larger frequency than visible light. d) different because gamma rays are made up of waves, whereas light is made up of particles.

5. As a new star evolves from a warm gas to a very hot body, the peak wavelength of its spectrum of electromagnetic radiation should a) change from the ultraviolet to the visible range. b) change from the infrared to the visible wavelengths. c) increase from the visible to infrared wavelengths. d) remain the same.

6. A blackbody is an idealized object that a) reflects and emits light with the same intensity at all wavelengths. b) neither reflects nor emits light. c) both reflects and emits light in a manner determined by its temperature. d) reflects no light and emits light in a manner determined by its temperature.

7. The specific colors of light emitted by an atom in a hot, thin gas (e.g., in a tube in a laboratory or a gas cloud in space) are caused by a. the vibrations of the electrons within the atom. b. an electron dropping into the nucleus and causing changes in the energy of the nucleus. c. electrons jumping to lower energy levels, losing energy as they do so. d. protons jumping from level to level.

8. The hot, dense gas existing in the Sun emits energy a. at all wavelengths uniformly. b. at all wavelengths, with a peak at one particular wavelength (color). c. only at certain wavelengths and no others. d. mostly at the longest and shortest wavelengths, less in between.

9. The reason the primary mirror of an astronomical telescope is often polished to a parabolic shape is a. to avoid the chromatic aberration that would be produced by an equivalent spherical mirror. b. that it is lighter and easier to mount in a telescope. c. that it is easier to produce, even though the resulting mirror will produce more spherical aberration than an equivalent spherical mirror. d. to avoid spherical aberration.

10. The future EELT (European Extremely Large Telescope) will have a diameter of 40m. How many times larger will be the light gathering-power of the EELT compared to one of the Keck telescopes (which has a diameter 10 m) ? a. 2 times larger b. 4 times larger c. 8 times larger d. 16 times larger

1. A correct description for the relationship between the period of revolution (P) and the distance of a planet to the Sun (A) would be a) P2 is proportional to A3 b) P is proportional to A2. c) P is proportional to A. d) P does not correlate at all with A.

2. __________ was the first person to truly solve the problem of accurately describing planetary motion. a) Copernicus. b) Tycho. c) Kepler. d) Galileo.

3. Which situation does NOT correspond to having a force acting on the object: a) a car traveling with constant speed on a straight road. b) a car traveling with constant speed around a bend. c) a planet traveling in its orbit around the Sun. d) a car slowing down

4. You are an astronaut taking a spacewalk to fix your spacecraft. You are working with a hammer when your lifeline breaks and you start drifting away. To return safely to your spacecraft you should a) throw the hammer at the spaceship b) throw the hammer in the direction opposite to the space ship. c) use a swimming motion with your arms. d) kiss your ship good bye.

5. Which fundamental misconception(s) made Ptolemy's geocentric model very complicated and prevented it from adequately describing the movements of bodies in the Solar System? I) The Sun is at the center of the universe. II) All heavenly bodies move in combinations of perfect circles. III) The Earth is at the center of the universe. IV) The stars never move. a) I and IV. b) III only. c) IV only. d) II and III. e) III and IV

6. Observations of Venus are at odds with the geocentric model because in this model a. Venus would not be expected to significantly change in size b. Venus would never appear in "full" phase c. Venus would never show retrograde motion d. Venus would not be visible for half of the year

7. Galileo's discovery of the moons of Jupiter was shocking because it showed those who believed Earth to be at the center of the Universe that a. A planet could have more than one moon b. Earth was unusual to have only one moon c. Gravity could hold a moon in orbit d. Jupiter does not move e. Objects could move around a moving object that wasn't Earth

8. Which of the following pairs of masses exert the largest gravitational force on each other?

9. If the radius of the Earth was doubled, your weight would be a) less than half your current weight b) half your current weight c) the same d) double your current weight

10. According to Kepler's second law, the ranking of the planet's velocity, from faster to slower is: a) 1, 2, 3, 4 b) 3, 4, 2, 1 c) 2, 1, 4, 3 d) 1, 4, 2, 3

1. What was the most important difference in development between Isaac Newton's theory of planetary motion and that of Johannes Kepler? Select one: a.Newton based his theory on accurate telescopic observations, whereas Kepler used observations made by eye. b.Newton lived in England, which is famous for clear skies, whereas Kepler lived on the Continent, which is notorious for bad weather. c.Newton lived in a freer political climate, whereas Kepler risked house arrest if his theory opposed the Bible or Aristotle. d.Newton developed his theory from first physical principles, whereas Kepler found the model that provided the best fit to the data

2. Which one of the following statements describes the Newtonian understanding of the mechanics of the solar system? Select one: a. The natural motion of the planets, asteroids and comets would be that of a straight line if there was no gravitational pull from the Sun. Since there is, they move in one of four possible trajectories (circle, ellipse, parabola, or hyperbola) b.The natural motion of the planets is uniform circular motion. It is the gravitational force of the Sun which distorts these orbits into ellipses. c.The planets are held in their orbits by a gravitational balance between the Sun (which is closer) and the stars (which are farther away). d.The planets are held in their orbits by a balance between gravitation (attractive) and magnetism (repulsive).

Suppose I am at Earth's equator at a time when my location is experiencing a high tide that is higher than usual. What is happening one quarter of the way around the equator at this same time? Select one: a. This location will experience an exceptionally low tide. b.This location will also experience an exceptionally high tide. c.This location will experience a low tide, but it will be higher than usual. d.This location will experience a high tide, but it will be lower than usual.

4. In 1675, Rømer measured the speed of light by Select one: a. opening a shutter on a lantern on a hilltop and measuring the time taken for light from an assistance's shuttered lantern to return. b. timing eclipses of Jupiter's satellites, which appeared to occur later when Earth was farther from Jupiter. c. reflecting light from a mirror rotating at a known speed and measuring the angle of deflection of the light beam. d. measuring how long it took the light from stars located at different distances to reach Earth.

5. When light passes through a prism of glass, the Select one: a.different colors or wavelengths of light are separated in angle by the prism. b.prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors that we see. c.prism adds colors to different parts of the broadly scattered beam coming out of it. d.different colors are caused by multiple reflections in the prism and interference between the resulting beams.

6. Which one of the following statements is true? Select one: a.Visible light takes up only a very small part of the total range of wavelengths in the electromagnetic spectrum. b.Visible light is not part of the electromagnetic spectrum. c.Visible light takes up all of the electromagnetic spectrum. d.Visible light takes up most (but not all) of the total range of wavelengths in the electromagnetic spectrum.

7. A blackbody is an idealized object that Select one: a.reflects and emits light with the same intensity at all wavelengths. b.neither reflects nor emits light. c.reflects no light and emits light in a manner determined by its temperature. d.both reflects and emits light in a manner determined by its temperature.

8. Why does the Sun look red at sunset? Select one: a.The air molecules absorb blue light better than red light, allowing more red light to reach our eyes. b.The air molecules scatter red light better than blue light, so more red light reaches our eyes. c.The air molecules scatter blue light better than red light, so only red light arrives to our eyes.

10. When electromagnetic radiation (e.g., light) is Doppler-shifted by motion of the source away from the detector the Select one: a.measured frequency is higher than the emitted frequency. b.speed of the radiation is reduced below the emitted speed. c.detected wavelength is longer than the emitted wavelength. d.frequency remains the same, but the wavelength is shortened, compared to the emitted radiation.

1. Precession is the a) accuracy with which numbers are given in astronomy. b) slow motion of the Earth's rotation axis on the celestial sphere. c) apparent backward motion of planets on the celestial sphere. d) daily eastward motion of the Sun around the celestial sphere.

2. Which of the following is NOT a consequence of precession: a) The star that we refer to as the "north star" changes every few thousand years b) The seasons "shift" in time very slowly (March will feel more like winter in a few thousand years) c) The existence of seasons

3. The phase of the Moon during a lunar eclipse a) is always full. b) is always new. c) is always waning crescent. d) is always waxing gibbous.

4. Suppose tonight is new Moon. You are an astronaut on the side of the Moon facing the Earth. What phase of Earth do you see? a) You can't see the Earth because it is eclipsed by the Sun. b) new Earth c) first quarter Earth d) full Earth

5. If the Moon was third quarter last Saturday, what phase will it be this Saturday? (Remember that it takes about 30 days for the Moon to complete a full revolution) a) waning crescent b) waxing gibbous c) at or very near first quarter d) at or very near new

6. If you observe the Moon rising in the east as the Sun is setting in the west, then you know that the phase of the Moon must be a) new. b) first quarter. c) full. d) third quarter.

7. The eclipse on the right is a) a partial solar eclipse b) a total lunar eclipse c) a total solar eclipse d) a partial lunar eclipse

8. Why don't lunar eclipses happen at every full moon? a) The Moon's Orbit has 5 degree tilt with respect to the Earth's orbit around the Sun b) The moon's orbit sometimes takes it far enough away that the Earth's shadow has disappeared c) The Moon's orbit is not circular d) The moon cannot be full AND pass through the Earth's shadow.

9. At any instant in time (with the exception of Lunar eclipses), 50% of the Moon is illuminated by the Sun: a) True b) False

10. The Moon goes around the Earth in the same counter-clockwise direction in which the Earth rotates around itself and around the Sun a) True b) False

11. What would an astronaut on the near side of the Moon see during one month? a) See the Earth neither rise nor set, but stay nearly fixed at the same position in the sky. b) See the Earth rotate on its axis once every 24h. c) See the Earth go through phases d) All of the above

1. Eclipses of the Moon can occur only Select one: a.at new Moon. b.in June and December, when the Sun is near the solstices. c.in the spring and fall, when the Sun is on the ecliptic plane. d.at full Moon.

2. During a solar eclipse, the Select one: a. Moon comes between Earth and the Sun. b. Sun comes between Earth and the Moon. c. Earth comes between the Sun and the Moon. d. Sun goes below the horizon.

3. The maximum number of eclipses (both solar and lunar) that can occur in one calendar year is Select one: a.one. b.seven c.two d. five

4. In a period of 1 month, the Moon moves across the sky Select one: a.precisely along the celestial equator. b.parallel to the horizon. c.precisely along the ecliptic plane. d.along a plane that is neither the ecliptic plane nor the celestial equator, nor is it parallel to the horizon.

5. A lunar eclipse does not occur at every full moon because Select one: a. lunar eclipse cannot occur after sunset. b. the path of the Sun is inclined at an angle of 5° to the ecliptic plane. c. the plane of the Moon's orbit is at an angle to the plane of Earth's orbit. d. the orbit of the Moon is not a perfect circle.

6. When in total lunar eclipse, the Moon shows a reddish color because Select one: a. light from the northern and southern lights (the aurora) on Earth, which is predominantly red, illuminates the Moon. b. this is the color of the residual thermal glow from a still-warm Moon, after the abrupt removal of the heat of the Sun. c. only the red part of the solar spectrum is deflected onto it by Earth's atmosphere. d. the Moon is illuminated only by the residual glow from the dark side of Earth, which is predominantly red.

7. We can occasionally see a total eclipse of the Sun on Earth and the solar corona because Select one: a.the Sun is closer than the Moon b.the angular sizes of Sun and Moon, when viewed from Earth, are almost the same c.both the Moon and Sun move precisely along the ecliptic plane. d.the physical sizes of Sun and Moon are almost the same.

8. A total lunar eclipse can last more than an hour and a half, but a total solar eclipse never lasts more than 7 1/2 minutes. Why this difference? Select one: a. A total solar eclipse always occurs when Earth is at perihelion, and it is moving fastest at that time. b. A total solar eclipse always occurs when the Moon is at perigee, and it is moving fastest at that time. c. Earth's shadow at the Moon's distance is much larger than the Moon's shadow at Earth's distance. As Earth rotates, this narrow lunar shadow sweeps quickly over any given spot. d. Both Earth and the Moon move clockwise in their orbits, as seen from the north. Thus during a solar eclipse Earth and Moon are moving in opposite directions, and during a lunar eclipse they are moving in the same direction.

9. The word planet is derived from a Greek term meaning Select one: a. wanderer. b.astrological sign. c.bright nighttime object. d.non-twinkling star.

10. The Ptolemaic model of the universe included each of the following features, except one. Which one is the exception? Select one: a.The planets move in circular orbits called epicycles. The centers of the epicycles move along circular orbits called deferents. b.The Sun and Moon revolve around Earth. c.The apparent daily motion of the stars is due to the rotation of Earth. d.Comets are within Earth's atmosphere.

1. If the unaided human eye is sensitive enough to see about 6000 of the stars in the entire sky, about how many stars can be seen from the North Pole? a. All 600 of them every night b. only half (3000) because the rest are below the horizon all the time c. All 6000 of them; 3000 in the Summer and 3000 in the Winter

2. What basic pattern do stars seem to trace out in our sky if you watch (or photograph) stars near the north celestial pole for a period of several hours? a. circles, with the north celestial pole at the center b. spirals, as the stars move while Earth rotates c. almost straight lines, rising from the horizon towards the zenith d. ellipses, with the north pole as one focus

3. The two coordinates used by astronomers to define the position of a star in the sky that is applicable anywhere on Earth are a. azimuth and elevation b. latitude and longitude c. horizontal and vertical angles d. right ascension and declination.

4. The summer solstice position coordinates are RA = 6h, declination = +23.5°. What are the coordinates of the winter solstice? a. RA = 18h, declination = +23.5° b. RA = 0h, declination = 0° c. RA = 12h, declination = -23.5° d. RA = 18h, declination = -23.5°

5. What is the primary cause of Earth's seasons? a. The orbit of Earth is an ellipse, so Earth is not always at the same distance from the Sun. b. Earth's rotation axis tilts with respect to the plane of its orbit around the Sun. c. Earth's precession axis precesses (wobbles). d. In accord with Kepler's Second Law, Earth moves faster during parts of its orbit around the Sun and more slowly during other parts.

6. At what time of the year will the shadow of a vertical pole (a sundial) at any site in the northern hemisphere be the shortest? a. noon, August 5, midsummer b. noon, December 21, at the beginning of winter c. noon, June 21, at the beginning of summer

7. At rise time star A is at the position: a. 1 b. 2 c. 3 d. 4

8. Star B is observe at position #4 at 6PM. Where can it be found at midnight? a. 1 b. 2 c. 3 d. 4

9. Which of the following is NOT true: a. Star B never sets for this observer b. Star B has a lower declination than star A c. Star A is unobservable for a fraction of the day d. Star B is not observable from the South Pole

10. Where is the observer? a. North Pole b. Tropic of Cancer c. Equator d. South Pole

1. The ecliptic is defined as the Select one: a.line traced in our sky by the Sun over one year against the background stars. b.line in the sky that is perpendicular to Earth's spin axis. c.line traced in our sky by the Moon each month against the background stars. d.band of constellations through which the Sun and Moon move in our sky

2. The ecliptic crosses the celestial equator at Select one: a.one point only, known as the vernal equinox. b.two points, known as solstices. c.the meridian. d.two points, known as equinoxes.

3. What is the primary cause of Earth's seasons? Select one: a.The orbit of Earth is an ellipse, so Earth is not always the same distance from the Sun. b.Earth's rotation axis tilts with respect to the plane of its orbit around the Sun. c.Earth's precession axis precesses (wobbles). d.In accord with Kepler's Second Law, Earth moves faster during parts of its orbit around the Sun and more slowly during other parts.

4. The vernal equinox is one time of the year when the Sun Select one: a.crosses the Moon's orbital path in the sky. b.is at its lowest point in the sky at midday. c.crosses the ecliptic plane. d.crosses the celestial equator.

5. In San Luis Obispo, how many times during the year will the Sun pass precisely through your zenith (that is, directly on top of you)? Select one: a.once b.every day for a half a year c.never d.twice

6. Precession is Select one: a.the daily spinning motion of Earth, producing the apparent motion of the Sun and the stars. b.the motion of Earth along its orbital path during a year. c.the slow coning motion of the spin axis of Earth, similar to that of a spinning top. d.another name for a parade.

7. A science fiction writer, writing a story about inhabitants on Earth in 14,000 A.D. who have survived a disaster that included the loss of modern navigational aids, describes them traveling due north across barren wastes by walking toward Polaris, the Pole Star. What is wrong with this situation? Select one: a.Polaris will no longer be visible since its lifetime is only a few thousand years. b.Polaris will no longer be due north, because of Earth's precession. c.By that time, Polaris will be due south, not due north, because of the reversal of Earth's spin axis. d.Polaris will have moved away from due north since it is moving rapidly with respect to surrounding stars.

8. By observing the sky closely night by night, you would note that a particular star rises Select one: a.about 4 minutes earlier every night. b.about 4 minutes later every night. c.at the same time every night. d.at a varying time every night, sometimes earlier, sometimes later than a specified time.

9. A solar day is the time it takes Earth to rotate around its axis between two consecutive solar positions (i.e. high noon to high noon or sunset to sunset). A sidereal day is the time it takes Earth to rotate around its axis between two consecutive positions of a distant star (i.e. Vega on the eastern horizon to Vega again on the eastern horizon). Which is longer? Select one: a.They are always the same length. b.A sidereal day is always longer. c.A solar day is always longer. d.A sidereal day is longer when Earth is farther from the Sun (northern summer), but a solar day is longer when Earth is closer to the Sun (northern winter).

10. Why do we see different phases of the Moon? Select one: a.The rotation of the Moon around its own axis causes us to see different amounts of the sunlit side of the Moon. b.The distance of the Moon from Earth changes because of the elliptical orbit of the Moon, causing the sunlit side of the Moon to move relative to Earth. c.The motion of the Moon in its orbit around Earth causes us to see different amounts of the sunlit side of the Moon d.The motion of the Moon in its orbit around Earth causes us to see different amounts of Earth's shadow falling on the Moon.

1. One arcminute is equal to Select one: a.1/60 degree. b.60 degrees. c.1/60 of a full circle. d.1/60 arcsecond.

2. The following distance units, arranged in size from smallest to largest, are Select one: a.km, ly, AU, pc b.AU, pc, km, ly c.km, AU, ly, pc d. ly, AU, pc, km

3. Heavy elements, such as those throughout Earth and within our bodies, appear to have been formed Select one: a.only during the initial Big Bang formation of the universe. b.inside the Sun. c.by radioactive decay here on Earth. d.deep inside some now-vanished star.

4. In science, if new observations disagree with a well established theory then Select one: a.the observations must be discarded. b.the theory must be discarded immediately and completely c.the theory must be modified. d.this should be accepted as part of the overall incomprehensibility of the universe, and both the observations and the theory should be retained.

5. According to the scientific method, a hypothesis that is proposed to explain a particular physical phenomenon is considered wrong if Select one: a.it appears to defy logic and logical reasoning. b.leading scientists in the world believe it is wrong. c.it disagrees with the accepted theory at the time of the proposal. d.it is in conflict with the results of just one reliable and repeatable observation.

6. Astronomers sometimes announce they have discovered a new solar system beyond our own, or a new galaxy beyond our own. Which choice correctly describes the terms "solar system" and "galaxy"? Select one: a..A solar system consists of planets and other objects orbiting around a star, whereas a galaxy is a system consisting of an immense number of stars. b.A solar system consists of an immense number of stars (i.e., suns), and a galaxy is a cluster of many such systems. c.A galaxy consists of planets and other objects orbiting around a single star, whereas a solar system is a system consisting of an immense number of stars (i.e., suns). d.A solar system is a large assemblage of stars similar to the Sun, whereas a galaxy is much larger and consists of all different types of stars.

7. In modern astronomy, the constellations are Select one: a.clusters of stars that are held together by the mutual gravitational attractions of the individual stars in the cluster. b. nearby galaxies to which astronomers have given specific names. c.88 regions of sky, covering the entire sky. d.12 regions of sky through which the Sun, Moon, and planets move as seen from Earth.

8. The nightly motion of objects across our the sky is caused by the Select one: a.rotation of Earth on its axis. b.revolution of Earth around the Sun. c.motion of the solar system around the galaxy. d.rotation of the whole celestial sphere of stars around the fixed Earth.

9. When we watch the nighttime sky, we find that Select one: a.most stars and constellations slowly rise in the east, pass overhead, and set in the west. b.the stars and constellations remain fixed in our sky, not rising or setting in a time as short as one night because they are so far away. c.most stars and constellations slowly rise in the west, pass overhead, and set in the east. d.all stars and constellations pass exactly ovehead at some point during the night

10. Imagine a bright star in the night sky. You watch it rise above the eastern horizon about 2 A.M. in the middle of February. About what time will it rise in the middle of March? Select one: a.4 A.M. b.10 P.M. c.2 A.M. d.midnight

1. There is no evidence of plate tectonics on Mercury. The most likely explanation is that A) the planet cooled too slowly and the mantle remained too soft. B) the planet cooled too rapidly and the mantle became too rigid. C) Mercury has no iron core like Earth. D) plate tectonics can only occur on a body with continents separated by oceans.

2. Venus has a higher surface temperature than Mercury. Which of the following is an explanation for this? A) Venus is closer to the Sun than Mercury is. B) Venus has a dense atmosphere of carbon dioxide. C) Venus is still contracting gravitationally and thus gives out more radiation than it receives. D) Venus has a higher albedo (reflectance) than Mercury.

3. A shield volcano is a A) volcanic dome on the side of a larger volcano that shields the surrounding plains from inundation by lava from the main vent. B) very broad volcano with gently sloping sides C) tall volcano with steep sides D) vast lava flood-plain originating from a ground-level fissure

4. On the surface of which planet have experiments been carried out to search for life-forms or evidence of life? A) Jupiter B) Mars C) Venus D) Mercury

5. Why would you expect to see no craters, such as those on the Moon or Mars, on Io, the innermost Galilean moon of Jupiter? A) because the surface is always reentering the planet's interior by subduction in rapid plate tectonic motion, similar to but faster than that on Earth B) because continuous rainfall quickly erodes and washes away all trace of craters C) because its liquid surface cannot maintain a crater, just as Earth's oceans cannot do D) because volcanoes are continuously depositing new material on the surface

6. Titan is Saturn's largest satellite. It is unusual among all the planetary moons because of its A) strong magnetic field. B) ocean of water under the icy crust C) dense atmosphere. D) rings.

7. Why is the strategy of searches for extraterrestrial life usually based upon a carbon chemistry? A) Carbon dioxide is the main ingredient of planetary atmospheres, both terrestrial and Jovian. B) Carbon is abundant and is versatile in forming complex, long-chain molecules. C) Most meteorites that reach Earth are composed of carbon. D) No other atom can combine easily with the abundant hydrogen and helium to form long molecules in interstellar gas.

8. Imagine a solar system just like ours but where the Sun is 30% more massive. What planet would you expect to find in the habitable zone? A) Mercury B) Venus C) Earth D) Mars

9. How have we been able to obtain samples of Martian rocks? A) Rocks have been collected and returned from the Moon to Earth by astronauts, now identified as Martian rocks blasted from this planet by a massive impact. B) Rocks have been blasted off Mars by impacts, and have landed on Earth as meteorites. C) We have not yet been able to obtain any Martian rock samples. D) Sample return missions have been flown in which a robotic rover collected rocks and returned them to Earth.

10. The Drake equation attempts to predict A) the probability that primitive life exists elsewhere in our galaxy. B) the number of inhabitable planets around stars in our galaxy. C) the number of technologically advanced civilizations in our galaxy.

1. In recent times, one method that has been used successfully to investigate the deep interior of the Sun has been to observe Select one: a.the progress of a solar-impacting comet. b.the deep atmospheric conditions, as encountered by a spacecraft as it entered the solar atmosphere. c.the spectrum and behavior of a sunspot, whose roots are deep inside the Sun. d.regular 5-minute oscillations and fluctuations of the surface.

2. Which part of the Sun is the origin of most of the light we see? Select one: a.the photosphere b.the core c.the chromosphere d.the corona

3. What is the source of the solar wind? Select one: a.gas escaping from X-ray-bright regions of the solar corona b.gas escaping through coronal holes c.gas flung out from the Sun's equatorial region by the centrifugal force due to the Sun's rotation d.gas flung out from solar flares

4. How does the number of sunspots on the Sun vary with time? Select one: a.relatively regularly, with a period of about 11 years b.They vary irregularly, with no periodicity. c.They increase and decrease every year as Earth revolves around the Sun. d.They increase and decrease regularly in number at exactly 11-year intervals.

5. The albedo of a planet is the fraction of energy that is Select one: a.absorbed. b.reradiated into space as infrared radiation by the planet. c.reflected by clouds in the atmosphere. d.reflected by the whole planet, including atmosphere and surface.

6. The greenhouse effect is the Select one: a.absorption of solar infrared radiation by the atmosphere and the subsequent heating of a planet's surface. b.absorption of solar ultraviolet radiation by gases in planetary atmospheres leading to atmospheric heating. c.protection of the surface of a planet from harmful infrared rays by atmospheric gases. d.absorption by atmospheric gases of infrared radiation emitted by a planet that has been heated by solar visible and ultraviolet radiation.

7. To form the present structure of Earth, which of the following mechanisms is most likely to have taken place while Earth was molten? Select one: a.Hydrogen and helium became highly compressed by gravity and sank to the core below a layer of heavier rocky material. b.All materials were thoroughly mixed by convection in the molten state, and Earth remained mixed as it cooled. c.Heavy elements sank to the center under gravity, while lighter materials rose to the surface and solidified into rocks.

8. Seismic waves inside Earth Select one: a. always travel in a straight line at a constant speed. b. travel at a constant speed but change direction (refract) as they travel through materials of different densities or compositions. C .travel at different speeds in materials of different densities or compositions and change direction (refract) as they move from one material to another. d. travel in straight lines with speeds that change as the waves move through materials of different densities or compositions.

9. Approximately how many tectonic plates make up Earth's surface? Select one: a. two (the eastern and western hemispheres) b. seven (one under each continent) c. hundreds d. about ten

10. The motions of large portions of Earth's surface, or "plates," are caused by Select one: a.the varying pressure of Earth's atmosphere, both daily and seasonally. b.tidal forces from the Moon and the Sun, acting on continental landmasses. c.convective flow of matter in Earth's interior. d.flexing of the surface due to solar heating and nighttime cooling.

11. In which layer of Earth's atmosphere is the ozone layer located? Select one: a.stratosphere b.mesosphere c.troposphere d.thermosphere

12. Which one of the following four theories about the origin of the Moon is now believed to be correct? Select one: a.An object about the size of Mars crashed into Earth and debris from the collision formed the Moon. b.The Moon formed separately in a different part of the solar nebula and was later captured by Earth. c.Earth and the Moon formed together, already orbiting each other. d.Earth was spinning so rapidly while still molten that a piece "spun off" to form the Moon.

1. The natural satellites (moons) of the planets in our solar system Select one: a. fall into two main classes: seven larger than 2000 km in diameter, the rest much smaller. b.are all small, less than 2000 km in diameter. c.fall into three main classes: three larger than Mercury, five others larger than our Moon, and the rest less than 300 km in diameter. d.are all approximately the size of our Moon or larger.

2. Table 7-2 of the book describes the seven largest satellites in the solar system. From these data it can be seen that the presence of an atmosphere correlates with Select one: a.diameter. The largest satellites have atmospheres, the smaller ones do not. b.average density. The satellites with the larger average densities are more likely to have atmospheres. c.none of the above. d.mass. The more massive the satellite, the more likely the satellite is to have an atmosphere.

3. Determination of the chemical composition of the atmospheres of the planets is carried out most effectively by what type of study? Select one: a.photometry—the measurement of the fading of light from their moons as they pass behind the planet's atmosphere b.measurement of their relative mean densities c.spectroscopy—the measurement of absorption features in their spectra d.measurement of their atmospheric temperature

4. The wide absorption features in the optical spectrum of Titan's atmosphere (see Figure 7-3b) are produced by Select one: a.methane gas, CH4. b.hydrogen gas, H2. c.oxygen gas, O2. d.water vapor, H2O.

5. The mass of the planet Jupiter is high and its atmosphere is relatively cool. What are the chances for the retention of gases within its atmosphere? Select one: a.poor for all gases because of the low temperature, thus all gases will be leaving Jupiter continuously b.good for all gases, including light (H2 and He) and heavier (CH4, NH3, H2O) molecules c.good for light (H2 and He) molecules but poor for heavier (CH4, NH3, H2O) molecules d.good for heavier (CH4, NH3, H2O) molecules but poor for light (H2 and He) molecules

6. A typical asteroid is made of Select one: a.rock and ice. b.rock and metal. c.ices of water, methane, and ammonia or perhaps ices with dust-sized grains of rock mixed in. d.ice with a liquid water core.

7. Comets are typically Select one: a.gaseous bodies from which some of the gas is pushed out by the Sun to form a long tail. b.slushy mixtures of liquid and ice. c.chunks of ice that begin to vaporize if they pass close to the Sun. d.chunks of rock a few tens to hundreds of kilometers in diameter.

8. Planets and satellites with a large amount of surface cratering generally have insignificant atmospheres. Why are these two conditions correlated? Select one: a.A large amount of cratering implies a small size, and this, in turn, implies a low escape speed. b.Most of the solar system debris that caused cratering was near the Sun. Thus heavily cratered planets and satellites are near the Sun where high temperatures result in high average molecular speeds. c.A large amount of cratering implies a small size, and this, in turn, implies a high escape speed. d.The impacts that create the craters also tend to vaporize the atmosphere.

9. In general, small bodies in the solar system are less likely than large bodies to possess a planet-wide magnetic field. Why should we expect size and magnetism to be correlated? Select one: a.Small bodies are more likely to be heavily cratered, and such impacts can destroy the mechanism that produces the magnetic field. b.A small body cools more rapidly and is less likely to possess a molten, liquid interior — one requirement for planet-wide magnetism. c.Magnetic fields are produced by the entire volume of a body. Smaller bodies have smaller volumes and hence smaller magnetic fields. d.Small bodies necessarily rotate more slowly, and a rapid rotation rate is one requirement for a planet-wide magnetic field.

10.The age of the solar system has been dated rather precisely to 4.56 billion years. What method was used to determine this number? Select one: a.determining the age of meteorites by radioactive dating b.calculating the age of the Sun c.calculating the age of Earth by counting layers of geologic deposit

The Earth revolves around the sun in a counter-clockwise direction, moving 1* per day (360* per 365 days). This motion causes the sun to appear to move... a)1* per day eastwards b)1* per day westwards c)15* per day eastwards d)15* per day westwards

If the Sun rises directly East on the Spring equinox, then three weeks later it will rise: a) Directly East b) North of East c) South of East

What causes the seasons?