Question 1

The jovian planets in our solar system

Accepted Answer

The jovian planets, Jupiter, Saturn, Uranus, and Neptune, all have extensive ring systems around their equators. The jovian planets (Jupiter, Saturn, Uranus, and Neptune) all have rings around their equators.

Question 2

Conservation of angular momentum means that a spinning body tends to:

Accepted Answer

Conservation of angular momentum means that the total angular momentum of a system remains constant, unless an external torque is exerted on it. In the case of a spinning body, this means that it will continue to spin at a constant rate unless an external torque (like friction with the atmosphere or collision with another object) slows it down. Therefore, the best choice is E, which states that the spinning body will keep spinning. Conservation of angular momentum means that the total angular momentum of a system is conserved. In the case of a spinning body, this means that the amount of angular momentum it possesses will remain constant unless an external torque acts upon it. Therefore, the spinning body will tend to keep spinning.

Question 3

A successful theory of the formation of the solar system must explain:

Accepted Answer

A successful theory of the formation of the solar system must be able to explain all observed properties of the solar system, including but not limited to the prograde rotation of planets, elliptical orbits, the asteroid belt, and atmospheric composition of the planets. A successful theory of the formation of the solar system must explain all observed properties of the solar system, including the direction of planetary rotation, the eccentricity of planetary orbits, the existence of the asteroid belt, and the differences in atmospheric composition between inner and outer planets.

Question 4

What happens when a solar nebula contracts?

Accepted Answer

When a solar nebula contracts, it conserves its angular momentum and hence flattens out and spins faster due to conservation of angular momentum. The gravitational potential energy is converted to thermal energy, hence the nebula heats up. Therefore, all of the above options are correct. When a solar nebula contracts, it conserves angular momentum, which causes it to flatten out and spin faster. The compression of gas also increases the temperature, causing it to heat up. Therefore, all the mentioned options occur when a solar nebula contracts.

Question 5

An alternative to the core-accretion theory that explains the formation of the jovian planets isthe:

Accepted Answer

The gravitational instability theory proposes that Jupiter and Saturn were formed through the direct collapse and fragmentation of the gas and dust within the solar nebula, while Uranus and Neptune formed through a combination of core accretion and gravitational instability. The gravitational instability theory suggests that the jovian planets formed directly from the collapse of the solar nebula without the need for a solid core as required by the core-accretion theory. Instead, gas and dust in the nebula clumped together and collapsed under their mutual gravitational attraction to form the gas giants we see today.

Question 6

Which of these is NOT a characteristic of the solar nebula theory?

Accepted Answer

The solar nebula theory does not necessarily dictate that larger planets should form closer to their star. In fact, some of the outer planets in our own solar system are much larger than the inner planets.

Question 7

In light of modern solar system theory, why do the orbits of the planets all lie in the sameplane?

Accepted Answer

According to modern solar system theory, the orbits of the planets all lie in the same plane because the solar nebula that gave birth to our solar system was a rotating disk, and the planets formed from this disk as well. The conservation of angular momentum of this rotating disk caused it to flatten into a disk shape, and from this disk, the planets formed in orbits around the Sun within the same plane. According to modern solar system theory, the orbits of the planets all lie in the same plane because the early solar nebula flattened into a disk, with the planets forming from material that was orbiting in that disk. This is known as the accretion disk model of planetary formation.

Question 8

One possible way that future scientists may determine whether the core-accretion model orthe gravitational instability theory better explains the formation of the jovian planet is:

Accepted Answer

Measuring the mass of the rocky material in the jovian planets' cores would help determine whether the core-accretion model or gravitational instability theory is more accurate, as the core-accretion model suggests that such planets formed from the accumulation of solid materials that eventually formed a rocky core, while the gravitational instability theory predicts that the planets formed as gas and dust collapsed under their own gravity without the need for a rocky core. By measuring the mass of the rocky core, scientists can determine which theory is more accurate. Measuring the metallic hydrogen layer or observing the changes in the rings or magnetic fields of the jovian planets does not directly relate to the formation theories. The core-accretion model predicts that a solid core of rocky material forms first, which then attracts gas from the surrounding disk to form a giant planet. The gravitational instability theory suggests that a clump of gas in the disk collapses under its own gravity to form a giant planet. By measuring the mass of the rocky material in the jovian planets' cores, scientists can determine whether the amount of core material is consistent with the core-accretion model or the gravitational instability theory.

Question 9

As a rotating gas cloud contracts, it spins:

Accepted Answer

As the gas cloud contracts, its size decreases and its rotation rate increases due to the conservation of angular momentum. This means that the product of the cloud's mass, radius, and angular velocity remains constant. Therefore, as the radius decreases, the cloud must spin faster to maintain the same angular momentum. As the gas cloud contracts, it conserves its total angular momentum, which is the product of its mass, velocity, and distance from the rotation axis. As the cloud's mass moves closer to the axis, its velocity increases, which leads to a decrease in its distance from the axis. However, because the total angular momentum is conserved, the cloud must spin faster to maintain its original value. Therefore, the correct choice is D, faster due to conservation of angular momentum.

Question 10

As the solar nebula contracts, it:

Accepted Answer

Conservation of angular momentum dictates that as the solar nebula contracts, it spins faster. This is similar to ice skaters spinning faster when they pull their arms in towards their body. Conservation of angular momentum dictates that as the solar nebula contracts, it will spin faster in order to maintain the same total angular momentum. This is similar to how a figure skater spins faster when they pull in their arms.

Question 11

In the conventional scenario, during which phase of planet formation caused the jovianplanets to form?

Accepted Answer

The jovian planets are thought to have formed during the core-accretion phase of planet formation, in which massive gas giants can form through rapid gas accretion onto a solid core. The core-accretion model suggests that the jovian planets formed through the accretion of a solid core first, which then attracted large amounts of gas and dust to form the massive atmospheres we see today. This process occurred during the later stages of planet formation, after the initial condensation and differentiation of the inner terrestrial planets.

Question 12

Dust is an important part of the nebular theory of solar system formation because dust isneeded to explain:

Accepted Answer

Dust is crucial in the nebular theory because it provides the solid material needed for the formation of rocky bodies, such as the inner planets, through the process of accretion.

Question 13

What is the process of accretion?

Accepted Answer

Accretion is the growth of an object by the accumulation of matter. It is a key process in the formation of planets and other astronomical bodies. Accretion is the process of an object growing larger by the accumulation of matter, usually through gravity. This is how planets and other bodies in our solar system were formed - particles in the solar nebula clumped together and gradually grew larger through accretion.

Question 14

What is true about solar system densities?

Accepted Answer

The answer of What is true about solar system densities?
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Question 15

What was the primary role of dust in the formation of the solar system?

Accepted Answer

Dust acted as condensation nuclei; platforms to which other particles could attach and form larger particles of matter. These larger particles eventually combined to form the planets in our solar system. Dust acted as condensation nuclei, allowing other particles to attach and form larger particles of matter, eventually leading to the creation of planets and other celestial bodies in the solar system.

Question 16

What is the role of irregularities in the solar system in terms of theories of its origin?

Accepted Answer

Irregularities in the solar system, such as the tilt of Uranus and the clustering of asteroids in the asteroid belt, introduce a need for flexibility in theories of the solar system's origin. These irregularities challenge the idea of a perfectly orderly and uniform formation process, leading scientists to consider alternative explanations and possibilities. Irregularities in the solar system, such as the tilt of Uranus, the unusual orbit of Neptune, and the Kuiper Belt, introduce a need for flexibility and revision in theories of the solar system's origin. These irregularities cannot be ignored and must be taken into account when developing new theories.

Question 17

Planetary orbits:

Accepted Answer

Planetary orbits are almost circular with low eccentricities, meaning their shape is close to a perfect circle and not elongated.

Question 18

The meteorites that strike Earth are:

Accepted Answer

Meteorites are considered the oldest rocks known because they are remnants from the early solar system, providing insights into its formation and history.

Question 19

What factor caused different planets to form out of different types of material?

Accepted Answer

The variation in temperature throughout the solar nebula played a crucial role in determining the types of materials that could condense and form into planets. Closer to the Sun, where temperatures were higher, only metals and silicates could condense, leading to the formation of terrestrial planets. Further out, where it was cooler, gases and ices could also condense, contributing to the formation of gas giants and ice giants.

Question 20

What might have made the original solar nebula begin to contract?

Accepted Answer

The shock wave from a nearby exploding star (supernova) could have provided the necessary external pressure or trigger to initiate the contraction of the original solar nebula, leading to the formation of the Solar System. This process is supported by evidence of short-lived radioactive isotopes found in meteorites, which are thought to be remnants of the early Solar System and could have been produced by nearby supernovae.

Quiz 6: The Solar System: Comparative Planetology and Formation Models