Astronomy 12
Final Exam Review
Part I- Multiple choice: Answer each question by shading the most appropriate bubble.
01. Astronomy is the study ofa. the stars and planets and their movements as well as their affects on the lives and behavior of human beings.
b. the weather and of atmospheric processes.
c. the structure and evolution of the earth's crust.
d. everything in the universe that lies above Earth's atmosphere. /
02. Which of the following terms would not be associated with astronomy?
a. horoscope
b. telescope
c. astrolabe
d. celestial sphere /
03. A planet is an object which
a. occurs only in our solar system.
b. is too faint to see.
c. orbits a star.
d. does not generate its own energy from nuclear reactions /
05. A galaxy is
a. a large cloud of gas.
b. an exploding star.
c. the object from which all other objects in the universe were formed.
d. a collection of a large number of stars bound by gravity. /
06. A(n) _____ is the totality of all space, time, matter, and energy.
a. universe
b. galaxy
c. planet
d. star /
07. Which of the following is arranged from the smallest to the largest in size?
a. planet, star, universe, galaxy
b. star, planet, galaxy, universe
c. planet, star, galaxy, universe
d. universe, galaxy, star, planet /
12. An imaginary sphere of infinite extent with Earth at its center on which the stars, planets, and other heavenly bodies appear to be located is known as the
a. Zodiac.
b. celestial sphere.
c. atmosphere.
d. Valhalla. /
18. The Sun rises in the east and sets in the west because
a. the Earth rotates on its axis.
b. the Earth revolves around the Sun.
c. the Moon revolves around the Earth.
d. the Earth ‘wobbles’ on its axis. /
26. The appearance of the sunlit face of the Moon at different points along its orbit, as seen from Earth, is referred to as a
a. parallax.
b. phase.
c. lunar eclipse.
d. solar eclipse. /
27. A _____ eclipse occurs whenever the Moon passes through some portion of the Earth's shadow.
a. solar
b. lunar
c. total
d. partial /
28. A _____ eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring Earth's view of the Sun.
a. solar
b. lunar
c. total
d. partial /
29. The darkest part of the shadow is called the
a. penumbra.
b. umbra.
c. baseline.
d. dark zone. /
30. The part of a shadow where the light source is only partially blocked is called the
a. penumbra.
b. umbra.
c. baseline.
d. light zone. /
31. The difference in position of a star as seen from the Earth at different locations around the orbit of the Sun is known as
a. triangulation.
b. transit.
c. stellar parallax.
d. precession. /
32. During its orbital period, as a planet moves closer to the Sun, the orbital velocity of the planet ___.
(a) increases
(b) decreases
(c) remains the same /
33. According to Newton’s law of universal gravitation, the force of attraction between any two masses is directly related to the ___.
(a) distance between the masses
(b) product of the two masses
(c) velocity of the two masses
(d) sum of the two masses /
34. According to Kepler, planetary orbits are ______in shape.
a. elliptical b. circular c. spiral d. wavy /
35. What are the four Terrestrial Planets?
(a) Charon, Earth, Uranus, Mars
(b) Mars, Venus, Mercury, Earth
(c) Venus, Pluto, Mercury, Jupiter
(d) Neptune, Uranus, Sol, Jupiter /
35. What are the four Jovian Planets?
(a) Saturn, Neptune, Jupiter, Uranus
(b) Mars, Ceres, Mercury, Saturn
(c) Uranus, Mercury, Mars, Neptune
(d) Charon, Neptune, Uranus, Mars /
36. What is another name for an interstellar gas cloud?
(a) Nebula (b) Coma (c) Corona (d) Solar wind /
37. What solar system object revolves around the Sun, has enough gravity to form a nearly round shape, and have no other objects of similar size in it’s orbit?
(a) Planet (b) Comet (c) Meteoroid (d) Asteroid /
40. What method has been used in the successful search for planets around stars other than the Sun?
(a) Hubble Space Telescope photography of faint, nearby companions of stars
(b) detection of the spectral signature of methane gas near the star, since this gas is known to be a major constituent of the atmospheres of major planets
(c) measurement of the "wobble" of a star, caused by the orbital motion of the planet, detected either by accurate positional measurement of the star or by spectral Doppler shifts in the stars spectrum
(d) detection of the bending of light due to strong gravitational fields between Earth and the star system. / either C or D
41. What happens when an object gains more matter through its gravitational pull.
(a) Accumulation (b) Accretion (c) Evaporation (d) Outgassing /
42. What is the outward flow of charged particles from the sun called?
(a) Out gassing (b) Nova (c) Evaporation (d) Solar wind /
43. What is a planet that revolves around a star, other than our sun?
(a) protoplanet (b) planetesimal (c) extrasolar planet (d) exotroid /
44. Using Bode’s Law for planetary orbital radii, what is the next number in the sequence of numbers:
0.4, 0.7, 1.0, 1.6, 2.8, ____
(a) 10.0 (b) 5.2 (c) 4.8 (d) 4.4 /
56. In which of the following types of galaxies would you be least likely to find a newly-formed star?
a) Elliptical
b) Spiral
c) Irregular /
Use the diagram below to answer the next 3 questions:
57. Region #1 is referred to as the galactic _____.
a) halo
b) disk
c) bulge
d) cluster /
58. Region #2 is referred to as the galactic _____.
a) halo
b) disk
c) bulge
d) cluster /
59. Region #3 is referred to as the galactic _____.
a) halo
b) disk
c) bulge
d) cluster /
60. What does Hubble’s law tell us about how galaxies are moving?
a) All galaxies are moving away from us at the same velocity.
b) Galaxies close to us are receding from us slowly, and galaxies farther from us are receding more rapidly.
c) Galaxies close to us are receding from us rapidly, and galaxies farther from us are receding more slowly.
d) Galaxies have random distribution of velocities—there is no pattern. /
61. The cosmic microwave background radiation is
a) all of the radiation currently existing in the universe produced by all possible sources.
b) all of the radiation emitted by stars since the first stars were born.
c) leftover radiation from the original Big Bang that has been tremendously redshifted by the expansion of the universe.
d) radio emission from various radioactive galaxies. /
Part II- Short Answer: Answer each question on the test paper in the space provided.
49. Label the phases of the Moon. Indicate phase name below its image.
New Moon / Waxing Crescent / 1st Quarter / Waxing Gibbous / Full Moon / Waning Gibbous / 3rd Quarter / Waning Crescent50. Draw a diagram that would illustrate a lunar eclipse.
51. Draw a diagram that would illustrate a solar eclipse. Indicate the regions on Earth’s surface where total and partial eclipses would be seen.
52. Construct a Venn Diagram comparing and contrasting the geocentric and heliocentric models of the universe.
53. Draw a label a diagram that illustrates the geocentric model of the solar system. Be sure to include the following parts: deferent, epicycle, planet, Earth, Sun.
54. Define perihelion and aphelion.
Perihelion is the point on the orbital path of a planet closest to the Sun; aphelion is the point on the orbital path of a planet farthest from the Sun.
55. State Kepler’s 3 Laws of Planetary Motion.
· 1st: the orbit of a planet about the Sun is an ellipse with the Sun at one focus
· 2nd: a line joining a planet and Sun sweeps out equal areas in equal time intervals (i.e. a planet travels fastest at the perihelion and slowest at aphelion)
· 3rd: the period of a planet’s orbit squared (in years) is equal to the orbital radius of the planet cubed (in AU) (i.e. P2 = a3)
56. State Newton’s Law of Universal Gravitation.
The gravitational attractive force between two objects (i.e. a planet and the Sun) is directly related to the product of the mass of the two objects and inversely related to the square of the distance between them.
57. State Newton’s three laws of motion.
· First law: The velocity of a body remains constant unless the body is acted upon by an external force.
· Second law: The acceleration a of a body is parallel and directly proportional to the net force F and inversely proportional to the mass m, i.e., F = m x a.
· Third law: For every action, there is a reaction force, equal in magnitude (i.e. size) but opposite in direction
58. The orbital distance from Saturn to the Sun is approximately 10.0 A.U. Using Kepler’s 3rd Law of Planetary Motion (P2 = a3), what is the period of Saturn (or the time it takes Saturn to revolve around the Sun)?
P2 = a3 à P = √(10.0 AU)2 = 31.6 years
59. It takes Mars 688 days to revolve around the Sun. What is its orbital distance from the Sun?
Convert 688 days to years….688/365 = 1.88 years
P2 = a3 à a = cube root [(1.88 years)2] = 1.52 AU
60. State Newton’s revisions to Kepler’s Laws of Planetary Motion.
· 1st law: Newton agreed with Kepler but said that orbits could be elliptical if bound and the planet would continue to orbit regularly. Orbits could be parabolic or hyperbolic if unbound (i.e. planet passes Sun once and leaves Solar System)
· 2nd law: Newton said that the change in velocity or acceleration of a planet around the Sun is due to gravity
· 3rd law: Newton agreed that P2/a3 ratio was true for all planets in Solar System but was able to use gravity to determine the mass of Sun
61. State Bode’s Law. Compare its usefulness and accuracy to Kepler’s 3rd Law of Planetary Motion.
Bode’s law is a pattern of numbers that predict the orbital distances (in AU) from the Sun to all the planets with reasonable accuracy:
0.4, 0.7, 1.0, 1.6, 2.8, 5.2, 10.0, 19.6, 19.6, 38.8
It is useful for approximate distances but only useful for planets and not other Solar System objects. Kepler’s 3rd law can be used to find orbital distances of any Solar System object.
62. Use Bode’s Law to predict the orbital radius of the Asteroid Belt.
At 2.8 AU in the Bode’s law pattern, a planet was predicted to exist. After careful searching, astronomers determined that at this distance, the Asteroid Belt resides and not a planet.
63. Using Newton’s law of gravitation, if the distance between a planet and the Sun increases by a factor of 4, how does the force of gravity between the planet and Sun change?
The force of gravity would decrease by a factor of 16 (i.e. 42 = 16).
64. List Newton’s laws of motion and an example for each.
{see answer to #67; examples will vary}
65. List the major types of structures in the solar system, from the largest to the smallest mass.
· Sun, planets, moons, asteroids, comets
66. Why is Pluto no longer considered a planet?
· It has a highly eccentric orbit (eccentricity = 0.25).
· It is a very rocky object.
· Numerous trans-Neptunian objects the size of Pluto have been discovered.
67. Explain how the planets in our solar system were formed.
6 Steps to Form a Solar System
THE NEBULAR HYPOTHESIS
1. Solar Nebula Forms
· A huge cloud of cold gas and dust.
· Many times larger than our present solar system.
· Probably spinning very slowly.
2. Formation of the Protosun
· Under the influence of gravity, the solar nebula condensed into a dense central region (the protosun) and a diffuse outer region (the protoplanetary disk).
· Began to spin faster, flattened out, and central region heated up.
3. Rings and Planetesimals
· Instabilities in the rotating disk caused regions within it to condense into rings under the influence of gravity.
· Gradually, planetismals formed in these rings.
4. Terrestrial or Rocky Planets
· The planetismals attracted each other by gravity and collided to build planets.
· Closest to the protosun, only rocky material and metals could withstand the heat, and so the planets in this region are made mainly of these materials.
5. Jovian or Gas Giants
· In the outer part of the disk, the bodies formed from planetesimals made of rock and ice.
· They became big enough to attract large amounts of gas around them.
· Soon after these gas planets formed the protosun became a full-fledged star.
6. Remaining Debris
· Radiation from the Sun blew away most of the remaining gas and other material in the planetary solar system.