Question 1

What is the giant impact hypothesis for the origin of the Moon?
A) The Moon formed from material blasted out of the Earth's mantle and crust by the impact of a Mars-size object.
B) The Moon formed when two gigantic asteroids collided with one another.
C) The Moon originally was about the same size as Earth, but a giant impact blasted most of it away so that it ended up much smaller than Earth.
D) The Moon formed just like the Earth, from accretion in the solar nebula.

Accepted Answer

The giant impact hypothesis proposes that the Moon formed from material ejected from the Earth's mantle and crust by the impact of a Mars-size object, which eventually coalesced into the Moon.

Question 2

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

Accepted Answer

As the solar nebula shrank in size, it got hotter (due to gravitational potential energy being converted into thermal energy), its rate of rotation increased (due to conservation of angular momentum), and it flattened into a disk (due to collisions between particles causing them to align in the same direction). Option B is incorrect because density actually decreased as the solar nebula expanded, not increased. Option C is incorrect because the solar nebula actually lost energy as it shrank, due to radiation escaping into space. Option D is incorrect because it describes the eventual outcomes of solar system formation, not the changes that occurred in the solar nebula itself.

Question 3

The terrestrial planets in our solar system are ________.
A) Mercury, Venus, Earth, and Mars
B) Jupiter, Saturn, Uranus, and Neptune
C) Pluto and Eris
D) Mars, Jupiter, Saturn, Uranus, and Neptune

Accepted Answer

The term "terrestrial" refers to planets that are Earth-like or rocky, meaning they have a solid surface. The four planets that fit this description in our solar system are Mercury, Venus, Earth, and Mars. Option B includes Jupiter, Saturn, Uranus, and Neptune, which are gas giants with no solid surface. Option C includes Pluto and Eris, which are technically categorized as "dwarf planets" and not fully recognized as planets by the International Astronomical Union. Option D includes Mars, which is a terrestrial planet, but also includes gas giants that do not fit the definition of terrestrial.

Question 4

When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except ________.
A) carbon dioxide
B) water
C) ammonia
D) methane

Accepted Answer

Jovian planets, also known as gas giants, are composed mainly of hydrogen and helium, with small amounts of other elements. The hydrogen compounds mentioned in the question include water (H2O), ammonia (NH3) and methane (CH4). Carbon dioxide (CO2) is not a hydrogen compound, but rather a compound of carbon and oxygen.

Question 5

Which of the following types of material can condense into what we call ice at low temperatures?
A) Hydrogen compounds
B) Hydrogen and helium
C) Rock
D) Metal

Accepted Answer

Hydrogen compounds, such as water (H2O), can condense into ice at low temperatures. Helium and metals cannot form ice at low temperatures, and while some rocks may contain water, they cannot directly convert into ice.

Question 6

What do we mean by the frost line when we discuss the formation of planets in the solar nebula?
A) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense.
B) It is another way of stating the temperature at which water freezes into ice.
C) It marks the special distance from the Sun at which hydrogen compounds become abundant; closer to the Sun, there are no hydrogen compounds.
D) It is the altitude in a planet's atmosphere at which snow can form.

Accepted Answer

The frost line refers to the distance from the Sun beyond which the temperature was low enough for ices, such as water, methane, and ammonia, to condense into solid form. This led to the formation of icy planetesimals and eventually the outer gas giant planets.

Question 7

Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years pass?
A) You'll have 0.25 kilogram of the radioactive substance remaining.
B) All the material will have completely decayed.
C) You'll have 0.75 kilogram of the radioactive substance remaining.
D) You'll have 0.5 kilogram of the radioactive substance remaining.

Accepted Answer

After 10 years, half of the substance will have decayed, leaving 0.5 kg. After another 10 years (totaling 20 years), half of that remaining 0.5 kg will have decayed, leaving 0.25 kg.

Question 8

Which planet (besides Earth) has been visited by the largest number of robotic spacecraft?
A) Mars
B) Jupiter
C) Venus
D) Saturn

Accepted Answer

Mars has been visited by the largest number of robotic spacecraft, with over 50 missions to date. This is due to its proximity to Earth and the potential for finding evidence of past or present life on the planet.

Question 9

According to our theory of solar system formation, what are asteroids and comets?
A) Leftover planetesimals that never accreted into planets
B) The shattered remains of collisions between planets
C) Chunks of rock or ice that condensed after the planets and moons finished forming
D) Chunks of rock or ice that were expelled from planets by volcanoes

Accepted Answer

According to the theory of solar system formation, asteroids and comets are leftover planetesimals that never accreted into planets.

Question 10

Which moons are sometimes called the Galilean moons?
A) The four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto
B) The two largest moons in the solar system: Ganymede and Titan
C) The moons that orbit their planet "backward" compared to their planet's rotation, such as Neptune's moon Triton
D) The moons orbiting Uranus, which was once named "planet Galileo"

Accepted Answer

The four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto, were first observed by Galileo Galilei and are sometimes called the Galilean moons.

Question 11

The jovian planets in our solar system are ________.
A) Jupiter, Saturn, Uranus, and Neptune.
B) Mercury, Venus, Earth, and Mars
C) Pluto and Eris
D) Io, Europa, Ganymede, and Callisto

Accepted Answer

The jovian planets in our solar system are Jupiter, Saturn, Uranus, and Neptune.

Question 12

Which jovian planet does not have rings?
A) All the jovian planets have rings.
B) Jupiter
C) Neptune
D) Uranus
E) Mars

Accepted Answer

The answer of Which jovian planet does not have rings?
A)...

Question 13

What do we mean by accretion in the context of planet formation?
A) The growth of planetesimals from smaller solid particles that collided and stuck together
B) The formation of moons around planets
C) The solidification of ices, rocks, and metal from the gas of the solar nebular
D) The growth of the Sun as the density of gas increased in the center of the solar nebula

Accepted Answer

Accretion in the context of planet formation refers to the process of planetesimals growing by colliding and sticking together to form larger bodies. This process eventually leads to the formation of planets.

Question 14

According to our present theory of solar system formation, which of the following lists the major ingredients of the solar nebula in order from the most abundant to the least abundant?
A) Hydrogen and helium gas; hydrogen compounds; rock; metal
B) Hydrogen compounds; hydrogen and helium gas; metal; rock
C) Hydrogen and helium gas; rock; metal; hydrogen compounds
D) Hydrogen, water, methane, helium

Accepted Answer

Hydrogen and helium gas are the most abundant elements in the universe, and they were the main components of the solar nebula. Hydrogen compounds, such as water and methane, were also present, but in smaller amounts. Rock and metal were the least abundant ingredients of the solar nebula.

Question 15

The planet in our solar system with the highest average surface temperature is ________.
A) Venus
B) Mercury
C) Earth
D) Neptune

Accepted Answer

Venus has a thick atmosphere composed mostly of carbon dioxide which causes a strong greenhouse effect, trapping heat on the surface and leading to an average temperature of around 864 degrees Fahrenheit (462 degrees Celsius).

Question 16

In essence, the nebular theory holds that ________.
A) our solar system formed from the collapse of an interstellar cloud of gas and dust
B) nebulae are clouds of gas and dust in space
C) the planets each formed from the collapse of its own separate nebula
D) The nebular theory is a discarded idea that imagined planets forming as a result of a near-collision between our Sun and another star.

Accepted Answer

The nebular theory postulates that our solar system formed from the collapse of an interstellar cloud of gas and dust, which eventually accreted to form the sun, planets, and other celestial bodies.

Question 17

The Cassini mission to Saturn consists of
A) an orbiter that orbits Saturn and a probe that descended to the surface of Titan.
B) a large spacecraft that flew by Saturn on its way to other planets.
C) an orbiter that orbits Saturn and a probe that descended into Saturn's atmosphere.
D) a spacecraft that orbits Saturn and a sample return mission that landed on Titan, scooped up a surface sample, and will return it to Earth.

Accepted Answer

The Cassini mission included an orbiter that studied Saturn and its moons from orbit, and the Huygens probe, which descended to the surface of Titan, Saturn's largest moon.

Question 18

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

Accepted Answer

The period of heavy bombardment refers to the first few hundred million years after the planets formed, during which time most impact craters on the inner solar system bodies were formed. This bombardment is thought to have been caused by leftover planetesimals and debris from the formation of the solar system.

Question 19

According to modern science, what was the approximate chemical composition of the solar nebula?
A) 98% hydrogen and helium, 2% everything else
B) 50% hydrogen and helium, 50% everything else
C) 98% hydrogen, 2% helium
D) Roughly equal proportions of hydrogen, helium, water, and methane

Accepted Answer

According to modern science, the solar nebula, from which the solar system formed, was primarily composed of hydrogen and helium, with trace amounts of other elements making up the remaining 2%. This is known as the nebular hypothesis and is supported by observations of other star-forming regions and the chemical analysis of meteorites. Therefore, choice A is the best answer.

Question 20

The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from?
A) They were produced by stars that lived and died before our solar system was born.
B) They were produced by gravity in the solar nebula as it collapsed.
C) They have been present in the universe since its birth.
D) They were made by chemical reactions in interstellar gas.

Accepted Answer

The heavy elements that make up the terrestrial planets were produced by stars that lived and died before our solar system was born, in a process known as stellar nucleosynthesis. During the late stages of a star's life, it can fuse lighter elements into heavier ones, including those found in Earth's crust and mantle. When these stars eventually explode as supernovae, they eject their newly formed elements into space, providing the raw materials for the formation of new stars and planets.

Quiz 6: Formation of Planetary Systems: Our Solar System and Beyond

What is the giant impact hypothesis for the origin of the Moon?

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

The terrestrial planets in our solar system are ________.

When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except ________.

Which of the following types of material can condense into what we call ice at low temperatures?

What do we mean by the frost line when we discuss the formation of planets in the solar nebula?

Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years pass?

Which planet (besides Earth) has been visited by the largest number of robotic spacecraft?

According to our theory of solar system formation, what are asteroids and comets?

Which moons are sometimes called the Galilean moons?

The jovian planets in our solar system are ________.

Which jovian planet does not have rings?

What do we mean by accretion in the context of planet formation?

According to our present theory of solar system formation, which of the following lists the major ingredients of the solar nebula in order from the most abundant to the least abundant?

The planet in our solar system with the highest average surface temperature is ________.

In essence, the nebular theory holds that ________.

The Cassini mission to Saturn consists of

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

According to modern science, what was the approximate chemical composition of the solar nebula?

The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from?