Question 1

Which of these is NOT true of motions in the solar system?

Accepted Answer

A)   The orbital motion of the planets is in the same direction as the rotation of the Sun.
B)   All the planets orbit in the same direction as the solar nebula from which they formed.
C)   The orbital period of the planets increases with distance from the Sun.
D)   All the planets orbit the Sun in the same direction, except one.

Question 2

The timescale over which material in the solar nebula accreted to form the inner planets was about _____ years.

Accepted Answer

A)   100 million
B)   4.6 million
C)   4.6 billion
D)   100,000

Question 3

The low average density of the large, outer planets, which have high masses and hence high gravitational fields, is an indication of what fact about their interiors?

Accepted Answer

A)   The large, outer planets have hot, gaseous interiors, similar to the interiors of cool stars.
B)   The interiors of the large, outer planets are composed of water, methane, and ammonia.
C)   The large, outer planets are composed mainly of very light elements, such as hydrogen and helium.
D)   The interiors of the large, outer planets have not been condensed to liquid or solid form.

Question 4

According to current theories of planetary formation, why is Saturn less massive than Jupiter?

Accepted Answer

A)   Saturn formed far out in the solar system where gas and dust were not as readily available as where Jupiter formed near the Sun.
B)   Saturn formed in the inner part of the solar system where the rocky inner planets had already absorbed most of the material.
C)   Saturn was originally more massive but has been repeatedly struck by large planetesimals that have stripped off some of its matter.
D)   Jupiter formed first, using up or ejecting much of the material available in the outer solar system. D

Question 5

MOST of the planets orbit the Sun on or close to the

Accepted Answer

A)   plane of the Milky Way Galaxy.
B)   ecliptic plane.
C)   plane containing both north and south celestial poles and the zenith at Greenwich, England.
D)   equatorial plane.

Question 6

The MOST probable process for the formation or acquisition of the planets of the Sun is the

Accepted Answer

A)   capture of planets from outer space by gravity.
B)   relatively slow growth of smaller objects by collisions and mutual gravitational attraction.
C)   freezing of immense gas clouds by the cold temperature of space.
D)   breakup by tidal distortion of a single large companion body to the Sun.

Question 7

One particularly important collision in the early inner solar system about 100 million years after Earth's formation resulted in

Accepted Answer

A)   the extinction of 70 % of the species then in existence on Earth, including the dinosaurs.
B)   the formation of a secondary asteroid belt between the orbits of Earth and Venus.
C)   the destruction of the planet Vulcan, which had an orbit inside the orbit of Mercury.
D)   the formation of our Moon.

Question 8

The smallest of the planets in our solar system, as measured by its mass, is

Accepted Answer

A)   Venus.
B)   Neptune.
C)   Mercury.
D)   Mars.

Question 9

Which of these time sequences for the formation of the solar system is MOST probable?

Accepted Answer

A)   The Sun contracted first as a gas ball, and the planets and moons formed shortly afterward by accretion and condensation.
B)   The Sun formed first, the planets were spun off from the Sun, and the moons in turn were spun off from the planets.
C)   The planets formed first out of a cold nebula of gas and dust, followed by the Sun, which formed when the gas had become much hotter.
D)   The Sun formed initially, and the planets and major moons were captured much later as they drifted by the Sun.

Question 10

Which of these solar system bodies is MOST likely to have hosted liquid water in the past?

Accepted Answer

A)   Ceres
B)   Venus
C)   Europa
D)   Triton C

Question 11

The solar system formed about 4.5 billion years ago. What has been the rate of bombardment by space debris in the inner part of the solar system since then?

Accepted Answer

A)   There has been a relatively steady bombardment by both large and small pieces of debris since the formation.
B)   The rate of bombardment was very heavy just after the solar system's creation, but the rate has decreased steadily since then.
C)   The rate decreased steadily for about 400 million years after the solar system's creation. Then a very heavy bombardment began and lasted about 300 million years. The rate has been greatly reduced since then.
D)   The rate has been highly erratic with no clear pattern.

Question 12

The region outside the orbit of Neptune in which a large number of objects composed of rock and ice circle the Sun not far from the plane of the ecliptic is called the

Accepted Answer

A)   outer solar system.
B)   asteroid belt.
C)   Kuiper belt.
D)   Oort comet cloud.

Question 13

Viewed from a position above the north pole of the Earth, the direction of the motion of the planets in their orbits is

Accepted Answer

A)   clockwise.
B)   counterclockwise.
C)   clockwise except the direction of Venus.
D)   counterclockwise except the direction of Mercury. B

Question 14

Compared with the orbital distance of Earth from the Sun, the equivalent orbital distances for the outer planets are _____ times greater.

Accepted Answer

A)   between 2 and 20
B)   more than 10
C)   between 2 and 5
D)   more than 5

Question 15

The planet with the greatest mean density is

Accepted Answer

A)   Mercury.
B)   Earth.
C)   Jupiter.
D)   Neptune.

Question 16

The average density of a planet is

Accepted Answer

A)   its total mass divided by its total volume.
B)   the amount of mass in unit volume of the material on its surface.
C)   another way of describing its total mass.
D)   the mass of a unit volume (1 cubic meter)  of the material at its core.

Question 17

What is a "plutino"?

Accepted Answer

A)   any object in a 2:3 orbital resonance with Pluto
B)   any object with the same orbital resonance as Pluto
C)   any object in an orbit outside that of Pluto
D)   any object beyond the orbit of Neptune that has enough mass to assume a spherical shape

Question 18

Which of these correctly characterizes a similarity between our solar system and the exoplanet population that has so far been discovered?

Accepted Answer

A)   The gas giants in our solar system have a comparable mass and density to gas giants in exoplanet systems.
B)   The terrestrial planets in our solar system have a comparable mass and density to terrestrial planets in exoplanet systems.
C)   Exoplanet orbits have comparable eccentricity to orbits in our solar system.
D)   Only gas giant exoplanets have so far been discovered.

Question 19

What process heated the early solar nebula as it slowly condensed toward a central protosun?

Accepted Answer

A)   radioactive decay of heavy elements originally formed in the Big Bang
B)   release of heat as molecules formed and gases condensed into ices
C)   thermonuclear fusion in the protosun, followed by radiative heating of the nebula
D)   generation of heat by collisions of particles as they gained kinetic energy in falling toward the center of the nebula

Question 20

Which planet in our solar system has the greatest mass?

Accepted Answer

A)   Saturn
B)   Earth
C)   Uranus
D)   Jupiter

Exam 6: Formation of the Solar System

Which of these is NOT true of motions in the solar system?

Correct AnswerverifiedShow Answer

The timescale over which material in the solar nebula accreted to form the inner planets was about _____ years.

Correct AnswerverifiedShow Answer

The low average density of the large, outer planets, which have high masses and hence high gravitational fields, is an indication of what fact about their interiors?

Correct AnswerverifiedShow Answer

According to current theories of planetary formation, why is Saturn less massive than Jupiter?

Correct AnswerverifiedD

MOST of the planets orbit the Sun on or close to the

Correct AnswerverifiedShow Answer

The MOST probable process for the formation or acquisition of the planets of the Sun is the

Correct AnswerverifiedShow Answer

One particularly important collision in the early inner solar system about 100 million years after Earth's formation resulted in

Correct AnswerverifiedShow Answer

The smallest of the planets in our solar system, as measured by its mass, is

Correct AnswerverifiedShow Answer

Which of these time sequences for the formation of the solar system is MOST probable?

Correct AnswerverifiedShow Answer

Which of these solar system bodies is MOST likely to have hosted liquid water in the past?

Correct AnswerverifiedC

The solar system formed about 4.5 billion years ago. What has been the rate of bombardment by space debris in the inner part of the solar system since then?

Correct AnswerverifiedShow Answer

The region outside the orbit of Neptune in which a large number of objects composed of rock and ice circle the Sun not far from the plane of the ecliptic is called the

Correct AnswerverifiedShow Answer

Viewed from a position above the north pole of the Earth, the direction of the motion of the planets in their orbits is

Correct AnswerverifiedB

Compared with the orbital distance of Earth from the Sun, the equivalent orbital distances for the outer planets are _____ times greater.

Correct AnswerverifiedShow Answer

The planet with the greatest mean density is

Correct AnswerverifiedShow Answer

The average density of a planet is

Correct AnswerverifiedShow Answer

What is a "plutino"?

Correct AnswerverifiedShow Answer

Which of these correctly characterizes a similarity between our solar system and the exoplanet population that has so far been discovered?

Correct AnswerverifiedShow Answer

What process heated the early solar nebula as it slowly condensed toward a central protosun?

Correct AnswerverifiedShow Answer

Which planet in our solar system has the greatest mass?

Correct AnswerverifiedShow Answer

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