Solar System Dynamics Practice Test

Solar System Dynamics Practice Test

A good score is at least 30 correct. Answers are provided at the end. It is best to have a friend check your score the first time so that you won’t memorize the answers if you want to take the test again.

1. The term epicycle refers to

(a) the motion of a planet with respect to the stars.

(b) the variation in the Moon’s orientation with respect to Earth.

(c) the speed of a planet’s revolution around the Sun.

(d) the wobbling of Earth on its axis.

(e) a component of a planetary orbit according to Ptolemy.

2. Which of the following planet has the most known moons?

(a) Mercury

(b) Mars

(c) Saturn

(d) Uranus

(e) Pluto

3. An accretion disk is

(a) a ring around a planet such as Saturn.

(b) a region around a planet in which orbits are stable.

(c) the plane of the orbits of the planets around a star.

(d) a rotating, flat cloud of matter from which planets form around a star.

(e) a computer disk used for storing position data for celestial objects.

4. Fill in the blank in the following sentence. The names of meteor showers derive from the positions of the _____ in the sky, which tend to be the same, year after year, for any given meteor shower.

(a) escarpments

(b) originating comets

(c) originating asteroids

(d) radiants

(e) focal points

5. Fill in the blank in the following sentence. The theory of _____, given sufficient time to operate, results in the evolution of life forms that are better and better suited to the particular environment in which they live.

(a) natural selection

(b) biological entropy

(c) conservation of energy

(d) Thomas Malthus

(e) planetary evolution

6. According to the geocentric theory

(a) the Earth revolves around the Sun.

(b) the Sun revolves around the Earth.

(c) the Moon revolves around the Sun.

(d) the distant stars are reflections of Earth.

(e) everything is sitting still in the Universe.

7. A laser can be used in long-distance space communication when it is necessary to

(a) direct the energy in a narrow beam.

(b) use as wide a frequency range as possible.

(c) spread the radio waves over a wide angle.

(d) generate large amounts of intergalactic noise.

(e) slow down the rate of data transmission.

8. Entropy has a tendency to

(a) turn chaos into order.

(b) equalize temperatures.

(c) create life.

(d) make stars shine.

(e) make planets form from cosmic dust.

9. Thomas Malthus is known for his theory that

(a) the human population increases geometrically, but the food supply increases arithmetically at best.

(b) the human population increases arithmetically, but the food supply increases geometrically at best.

(c) both the human population and the food supply increase geometrically.

(d) war ultimately will bring about the destruction of any technologically advanced civilization.

(e) a desire to travel among the stars is a characteristic of any intelligent species.

10. The Pluto-Charon system is unique in the sense that

(a) the planet and the moon always keep the same faces toward each other.

(b) the planet and the moon are the same size.

(c) the moon is larger than the planet.

(d) both objects are believed to have once been moons of Neptune.

(e) they are much warmer than the other outer planets or their moons.

11. A comet might burn out because

(a) it falls into the Sun.

(b) a solar flare hastens the disintegration of its nucleus.

(c) it is struck by a small asteroid, which shatters its nucleus.

(d) either a, b, or c take place.

(e) No! Comets never burn out.

12. Attempts to determine the number of advanced civilizations in the Milky Way galaxy have been carried out mathematically using

(a) radio waves.

(b) star charts.

(c) optical telescopes.

(d) the Green Bank formula.

(e) the Malthusian formula.

13. The planet Venus has a retrograde orbit around the Sun

(a) because it was knocked out of alignment long ago by a collision with a protoplanet almost as large as itself.

(b) because it is influenced by the gravitational fields of Earth and Mercury.

(c) because it is tilted on its axis by almost 180 degrees.

(d) because it was originally from outside the Solar System and was captured by the Sun’s gravity after all the other planets were formed.

(e) No! The planet Venus does not revolve around the Sun in a retrograde manner, but in the same sense as all the other planets.

14. So-called minor collisions, small asteroids striking planets, have been suggested as a catalyst for

(a) wiping out all life.

(b) the evolution of intelligent life.

(c) creating dinosaurs.

(d) adding oxygen to the atmosphere.

(e) creating oceans.

15. The Milky Way galaxy contains about

(a) 20,000 stars.

(b) 200,000 stars.

(c) 2 million stars.

(d) 20 million stars.

(e) None of the above

16. Copernicus was one of the earliest astronomers to hypothesize that

(a) Earth revolves around the Sun.

(b) the stars revolve around the Sun.

(c) epicycles exist within other epicycles.

(d) the planets are more distant than the stars.

(e) the Milky Way is not the only galaxy in the Universe.

17. Planetary moons almost always have rotation periods that correspond to their orbital revolution periods

(a) because of tidal effects between the moon and the parent planet.

(b) because the moons orbit in the plane of the parent planet’s equator.

(c) because the moons were captured from interplanetary space by the parent planet’s gravity.

(d) because the moons are perfect spheres.

(e) No! Planetary moons almost never have rotation periods that correspond to their orbital revolution periods.

18. When we say a celestial body has a low albedo, we mean to say that it is

(a) relatively low in density.

(b) relatively low in specific gravity.

(c) nonspherical in shape.

(d) relatively dark in appearance.

(e) not a good place for life to evolve.

19. When a planet or moon that has many craters is viewed from a distance, some craters have bright lines that run outward from the center. Such lines are called

(a) subcraters.

(b) crateroids.

(c) escarpments.

(d) rift valleys.

(e) rays.

20. The age of the Solar System is believed by most scientists to be approximately

(a) 4.6 million years.

(b) 4.6 billion years.

(c) 10 billion years.

(d) 200 billion years.

(e) 4.6 trillion years.

21. The average time interval between major comet impacts on the Earth is estimated to be on the order of several

(a) decades.

(b) centuries.

(c) tens of millennia.

(d) tens of millions of years.

(e) tens of billions of years.

22. Orbital resonances can be caused by

(a) solar flares and sunspots.

(b) synchronization of a planet’s rotation rate with the rotation rate of the Sun.

(c) mutual gravitation between different moons of the same planet.

(d) powerful magnetic fields, such as the magnetosphere of Jupiter.

(e) radio-wave emissions from planets.

23. The “probability fallacy” refers to

(a) an overestimate of the chance that something will happen.

(b) an inaccurate estimate of the chance that something took place.

(c) inappropriate use of statistics.

(d) a statement of belief rather than an estimate of probability.

(e) the derivation of a theory based on faulty observation.

24. According to one theory, tektites come from

(a) the Sun.

(b) the Moon and Mars.

(c) the planet Mercury.

(d) comets.

(e) beyond the Milky Way galaxy.

25. A mutation is

(a) an eccentricity in a planet’s orbit.

(b) the formation of a planet from cosmic dust and rocks.

(c) a star that has been modified by a collision with another star.

(d) a change in the shape of a crater.

(e) none of the above.

26. On the surface of an outer-planetary moon, craters can last a long time even when the chemical composition is largely frozen water. This is so because

(a) water periodically boils up from the interior, freezing on the surface.

(b) tidal interactions with the parent planet heat the moon from within.

(c) the extremely low temperatures make the ice as hard as granite.

(d) the moon’s atmosphere prevents wind erosion.

(e) No! Craters on the surfaces of an outer-planetary moon do not last long.

27. A Sungrazer is

(a) an asteroid that falls into the Sun.

(b) a star that passes so close to the Sun that the two stars pull matter from each other.

(c) a comet that enters the solar corona at perihelion.

(d) a comet that passes directly between Earth and the Sun.

(e) a comet that passes directly behind the Sun as seen from Earth.

28. In order for an astronaut to travel to the other side of the Milky Way galaxy within the span of his or her lifetime,

(a) the space ship would have to be well streamlined.

(b) the space ship would have to use liquid fuel.

(c) the space ship would have to travel at almost the speed of light.

(d) the space ship would have to travel faster than the speed of light.

(e) No! No astronaut can possibly reach the other side of the Milky Way galaxy within the span of his or her human lifetime no matter how fast the space ship goes.

29. Project Ozma involved the use of

(a) the Hubble Space Telescope.

(b) unmanned space probes.

(c) time-exposure photography.

(d) radio telescopes.

(e) manned space flights.

30. Suppose that there are two celestial objects, X and Y. Object X has a visual magnitude of 2, and object Y has a visual magnitude of 3. Which of the following statements is true?

(a) Object X is 2.5 times as bright as object Y.

(b) Object Y is 2.5 times as bright as object X.

(c) Both objects are too dim to be seen without the aid of a telescope.

(d) Both objects are the same brightness, but they are of different colors.

(e) None of the statements is true.

31. According to the tidal theory of the formation of the Solar System,

(a) the planets formed from matter that two passing stars pulled from each other.

(b) the planets condensed from a disk of matter in orbit around the Sun.

(c) the planets formed from tidal interactions among gas and dust clouds.

(d) two stars collided directly, and the debris condensed into planets.

(e) the planets were captured by the Sun’s gravity from interstellar space.

32. One of the major moons of the outer planets is believed by some astronomers to have once been a planet itself that came too close to the larger planet and became a natural satellite. This moon is

(a) Io.

(b) Rhea.

(c) Triton.

(d) Ariel.

(e) Miranda.

33. The “dirty snowball” portion of a comet is called the

(a) Lyttleton portion.

(b) Whipple portion.

(c) nucleus.

(d) coma.

(e) tail.

34. Some ancient astronomers talked about “music of the spheres.” Today we believe that the phenomenon they described was

(a) a figment of their imaginations.

(b) caused by solar radiation.

(c) caused by Earth’s tidal interactions with the Moon.

(d) caused by tidal interactions among Earth, the Moon, and the Sun.

(e) noise produced by falling meteors.

35. The term “shooting star” refers to

(a) a visible meteor.

(b) a solar flare.

(c) meteoric dust.

(d) an asteroid.

(e) a planetary moon.

36. Ganymede is a moon of

(a) Mars.

(b) Jupiter.

(c) Saturn.

(d) Uranus.

(e) Neptune.

37. Titan, one of the moons of Saturn, has been suggested as

(a) a place where life must exist.

(b) a place with an Earthlike environment.

(c) the place with the most violent storms in the Solar System.

(d) a generator of powerful radio waves.

(e) a place where future interplanetary travelers ought to go.

38. The major moons of Uranus

(a) are all believed to be comets that were captured by Uranus’s gravitation.

(b) orbit in the same plane as Uranus orbits the Sun.

(c) have highly eccentric orbits.

(d) orbit almost directly over the planet’s poles.

(e) orbit in the same plane as the planet’s equator.

39. The Oort cloud is notable because it is a source of

(a) radiation.

(b) radio signals.

(c) infrared energy.

(d) fuel for the Sun.

(e) none of the above.

40. Which of the following statements is false?

(a) Each planet follows an elliptical orbit around the Sun, with the Sun at one focus of the ellipse.

(b) An imaginary line connecting any planet with the Sun sweeps out equal areas in equal periods of time.

(c) For each planet, the square of its sidereal period is directly proportional to the cube of its average distance from the Sun.

(d) In reality, no planet orbits in a perfect circle around the Sun; the orbits are always at least a little bit oblong.

(e) All the planets and all the planetary moons orbit in the same plane around the Sun.

Answers

1. E

2. C

3. D

4. D

5. A

6. B

7. A

8. B

9. A

10. A

11. D

12. D

13. E

14. B

15. E

16. A

17. A

18. D

19. E

20. B

21. D

22. C

23. C

24. B

25. E

26. C

27. C

28. C

29. D

30. A

31. A

32. C

33. C

34. A

35. A

36. B

37. E

38. E

39. E

40. E