Question 1

Earth's atmosphere resulted from the impact of icy planetesimals that originated in the outer regions of the Solar System.

Accepted Answer

A) True 
 B)False

Question 2

According to our theory of solar system formation,what three major changes occurred in the solar nebula as it shrank in size?

Accepted Answer

A) It got hotter,its rate of rotation increased,and it flattened into a disk. 
B) Its mass,temperature,and density all increased. 
C) It gained energy,it gained angular momentum,and it flattened into a disk. 
D) Its gas clumped up to form the terrestrial planets,nuclear fusion produced heavy elements to make the jovian planets,and central temperatures rose to more than a trillion Kelvin. 
A) It got hotter,its rate of rotation increased,and it flattened into a disk. 
B) Its mass,temperature,and density all increased. 
C) It gained energy,it gained angular momentum,and it flattened into a disk. 
D) Its gas clumped up to form the terrestrial planets,nuclear fusion produced heavy elements to make the jovian planets,and central temperatures rose to more than a trillion Kelvin.

Question 3

Which of the following best explains why we can rule out the idea that planets are usually formed by near-collisions between stars?

Accepted Answer

A) Studies of the trajectories of nearby stars relative to the Sun show that the Sun is not in danger of a near-collision with any of them. 
B) Stellar near-collisions are far too rare to explain all the planets now known to orbit nearby stars. 
C) A near collision might have created planets,but it could not have created moons,asteroids,or comets. 
D) A near collision should have left a trail of gas extending out behind the Sun,and we see no evidence of such a trail. 
A) Studies of the trajectories of nearby stars relative to the Sun show that the Sun is not in danger of a near-collision with any of them. 
B) Stellar near-collisions are far too rare to explain all the planets now known to orbit nearby stars. 
C) A near collision might have created planets,but it could not have created moons,asteroids,or comets. 
D) A near collision should have left a trail of gas extending out behind the Sun,and we see no evidence of such a trail.

Question 4

Based on our current theory of Earth's formation,the water we drink comes from

Accepted Answer

A) ice that condensed in the solar nebula in the region where Earth formed. 
B) chemical reactions that occurred in Earth's crust after Earth formed. 
C) chemical reactions that occurred in Earth's core after Earth formed. 
D) material left behind during the giant impact that formed the Moon. 
E) comets that impacted Earth. 
A) ice that condensed in the solar nebula in the region where Earth formed. 
B) chemical reactions that occurred in Earth's crust after Earth formed. 
C) chemical reactions that occurred in Earth's core after Earth formed. 
D) material left behind during the giant impact that formed the Moon. 
E) comets that impacted Earth.

Question 5

According to modern scientific dating techniques,approximately how old is the solar system?

Accepted Answer

A) 10,000 years 
B) 4.6 million years 
C) 4.5 billion years 
D) 14 billion years 
A) 10,000 years 
B) 4.6 million years 
C) 4.5 billion years 
D) 14 billion years

Question 6

Why did the solar nebula heat up as it collapsed?

Accepted Answer

A) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. 
B) As the cloud shrank,its gravitational potential energy was converted to kinetic energy and then into thermal energy. 
C) Radiation from other nearby stars that had formed earlier heated the nebula. 
D) The shock wave from a nearby supernova heated the gas. 
E) Collisions among planetesimals generated friction and heat. 
A) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. 
B) As the cloud shrank,its gravitational potential energy was converted to kinetic energy and then into thermal energy. 
C) Radiation from other nearby stars that had formed earlier heated the nebula. 
D) The shock wave from a nearby supernova heated the gas. 
E) Collisions among planetesimals generated friction and heat.

Question 7

Which of the following are relatively unchanged fragments from the early period of planet building in the solar system?

Accepted Answer

A) the moons of Mars 
B) asteroids 
C) Kuiper belt comets 
D) Oort cloud comets 
E) all of the above 
A) the moons of Mars 
B) asteroids 
C) Kuiper belt comets 
D) Oort cloud comets 
E) all of the above

Question 8

Observations of young stars (as well as theory)tell us that when the Sun was young the solar wind

Accepted Answer

A) was weaker than it is today. 
B) was stronger than it is today. 
C) was about the same strength as it is today. 
D) was nonexistent. 
E) blew outward only along the Sun's poles. 
A) was weaker than it is today. 
B) was stronger than it is today. 
C) was about the same strength as it is today. 
D) was nonexistent. 
E) blew outward only along the Sun's poles.

Question 9

What percentage of the solar nebula's mass consisted of rocky material?

Accepted Answer

A) 0 percent 
B) 0.4 percent 
C) 2 percent 
D) 20 percent 
E) 80 percent 
A) 0 percent 
B) 0.4 percent 
C) 2 percent 
D) 20 percent 
E) 80 percent

Question 10

Based on our theory of how our own solar system formed,we would expect that other solar systems would be quite common.

Accepted Answer

A) True 
 B)False

Question 11

What percentage of the mass of the solar nebula consisted of elements other than hydrogen and helium?

Accepted Answer

A) 0 percent 
B) 0.1 percent 
C) 2 percent 
D) 20 percent 
E) 80 percent 
A) 0 percent 
B) 0.1 percent 
C) 2 percent 
D) 20 percent 
E) 80 percent

Question 12

Process of Science: A scientific theory must produce testable hypotheses that are then evaluated when data are available.What testable hypotheses does nebular theory predict? Describe two hypotheses about solar systems that come from nebular theory that we can test when more data on other solar systems become available.

Accepted Answer

1.Larger planets should be in

Question 13

What do we mean by the period of heavy bombardment in the context of the history of our solar system?

Accepted Answer

A) the first few hundred million years after the planets formed,which is when most impact craters were formed 
B) the time before planetesimals finished accreting into planets,during which many growing planetesimals must have shattered in collisions 
C) the time during which heavy elements condensed into rock and metal in the solar nebula 
D) the period about 65 million years ago when an impact is thought to have led to the extinction of the dinosaurs 
A) the first few hundred million years after the planets formed,which is when most impact craters were formed 
B) the time before planetesimals finished accreting into planets,during which many growing planetesimals must have shattered in collisions 
C) the time during which heavy elements condensed into rock and metal in the solar nebula 
D) the period about 65 million years ago when an impact is thought to have led to the extinction of the dinosaurs

Question 14

The more massive planets in the solar system tend to be less dense than the lower mass planets.

Accepted Answer

A) True 
 B)False

Question 15

Suppose the entire solar nebula had cooled to a very low temperature before the solar wind cleared it away.Do you think Earth would be the same? Why or why not?

Accepted Answer

Ices would have condensed in the inner s

Question 16

Briefly summarize the observed patterns of motion in our solar system that are consistent with the nebular theory.

Accepted Answer

(a)All planets orbit the Sun countercloc

Question 17

According to our present theory of solar system formation,which of the following best explains why the solar nebula ended up with a disk shape as it collapsed?

Accepted Answer

A) It was fairly flat to begin with,and retained this flat shape as it collapsed. 
B) The force of gravity pulled the material downward into a flat disk. 
C) the law of conservation of energy 
D) It flattened as a natural consequence of collisions between particles in the nebula. 
A) It was fairly flat to begin with,and retained this flat shape as it collapsed. 
B) The force of gravity pulled the material downward into a flat disk. 
C) the law of conservation of energy 
D) It flattened as a natural consequence of collisions between particles in the nebula.

Question 18

As viewed from above Earth's North Pole,all of the planets orbit the Sun in the same (counterclockwise)direction.

Accepted Answer

A) True 
 B)False

Question 19

About 2% of our solar nebula consisted of elements besides hydrogen and helium.However,the very first generation of star systems in the universe probably consisted only of hydrogen and helium.Which of the following statements is most likely to have been true about these first-generation star systems?

Accepted Answer

A) There were no comets or asteroids in these first-generation star systems. 
B) Jovian planets in these first-generation star systems had clouds made of water and other hydrogen compounds. 
C) These first-generation star systems typically had several terrestrial planets in addition to jovian planets. 
D) Like the jovian planets in our solar system,the jovian planets in these first-generation systems were orbited by rings. 
A) There were no comets or asteroids in these first-generation star systems. 
B) Jovian planets in these first-generation star systems had clouds made of water and other hydrogen compounds. 
C) These first-generation star systems typically had several terrestrial planets in addition to jovian planets. 
D) Like the jovian planets in our solar system,the jovian planets in these first-generation systems were orbited by rings.

Question 20

The nebular theory of the formation of the solar system successfully predicts all but one of the following.Which one does the theory not predict?

Accepted Answer

A) Planets orbit around the Sun in nearly circular orbits in a flattened disk. 
B) the compositional differences between the terrestrial and jovian planets 
C) the equal number of terrestrial and jovian planets 
D) asteroids,Kuiper-belt comets,and the Oort cloud 
E) the craters on the Moon 
A) Planets orbit around the Sun in nearly circular orbits in a flattened disk. 
B) the compositional differences between the terrestrial and jovian planets 
C) the equal number of terrestrial and jovian planets 
D) asteroids,Kuiper-belt comets,and the Oort cloud 
E) the craters on the Moon

Exam 8: Formation of the Solar System

Earth's atmosphere resulted from the impact of icy planetesimals that originated in the outer regions of the Solar System.

According to our theory of solar system formation,what three major changes occurred in the solar nebula as it shrank in size?

Which of the following best explains why we can rule out the idea that planets are usually formed by near-collisions between stars?

Based on our current theory of Earth's formation,the water we drink comes from

According to modern scientific dating techniques,approximately how old is the solar system?

Why did the solar nebula heat up as it collapsed?

Which of the following are relatively unchanged fragments from the early period of planet building in the solar system?

Observations of young stars (as well as theory)tell us that when the Sun was young the solar wind

What percentage of the solar nebula's mass consisted of rocky material?

Based on our theory of how our own solar system formed,we would expect that other solar systems would be quite common.

What percentage of the mass of the solar nebula consisted of elements other than hydrogen and helium?

What do we mean by the period of heavy bombardment in the context of the history of our solar system?

The more massive planets in the solar system tend to be less dense than the lower mass planets.

Suppose the entire solar nebula had cooled to a very low temperature before the solar wind cleared it away.Do you think Earth would be the same? Why or why not?

Briefly summarize the observed patterns of motion in our solar system that are consistent with the nebular theory.

According to our present theory of solar system formation,which of the following best explains why the solar nebula ended up with a disk shape as it collapsed?

As viewed from above Earth's North Pole,all of the planets orbit the Sun in the same (counterclockwise)direction.

The nebular theory of the formation of the solar system successfully predicts all but one of the following.Which one does the theory not predict?

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light and Matter: Reading Messages from the Cosmos

Telescopes: Portals of Discovery

Our Planetary System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

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