Question 1

The three common substances believed to have been important in planet formation are

Accepted Answer

Rocks, ices, and gas are the three common substances believed to have been important in planet formation. Rocks and ices formed the solid materials from which planets could form, while the gas provided the material for the atmospheres of these planets.

Question 2

The manner in which the terrestrial planets formed was

Accepted Answer

The most widely accepted theory for the formation of terrestrial planets is the accretion of solid planetesimals containing mostly rocky material. These planetesimals collided and stuck together gradually forming larger and larger bodies until the terrestrial planets were formed. There was no significant amount of gas in the region of the solar system where the terrestrial planets formed.

Question 3

The temperature began to rise at the center of the solar nebula because

Accepted Answer

The temperature began to rise due to the process of gravitational contraction, which caused the material in the center of the nebula to collide and increase thermal energy. This is known as the nebular hypothesis, which is the most widely accepted explanation for the formation of our solar system.

Question 4

The material from which our solar system formed is believed to be

Accepted Answer

The most widely accepted theory of solar system formation is the nebular hypothesis, which suggests that the solar system was formed from a cold, dark cloud of gas and dust known as a nebula. Over time, gravitational forces caused the nebula to collapse and spin, eventually forming the sun and the planets.

Question 5

Suppose you were to go back in time and explore the early solar nebula (during the formation of the solar system).If you were to travel outward from the protosun,the first solid material you would encounter would be

Accepted Answer

During the early solar system, the protosun heated up the material in the nebula causing it to evaporate and travel away from the sun. As this material cooled, it condensed into solid particles made up of iron and rocky material, forming the first solid material encountered as one travels outward from the protosun.

Question 6

A proplyd is

Accepted Answer

A proplyd is a protoplanetary disk, which is often observed around young stars in regions such as the Orion nebula. The term "proplyd" is short for "protoplanetary disk."

Question 7

The process of accretion in planetary formation is the

Accepted Answer

Accretion in planetary formation involves the slow accumulation of solid particles by gravity and collision into larger, solid objects. This process takes millions of years and gradually forms planets. Options B, C, and D describe other processes but are not related to accretion in planetary formation.

Question 8

More than any other,which physical parameter probably controlled the early evolution of the planetary system and dictated the characteristics of the planets that eventually formed?

Accepted Answer

The temperature distribution within the nebula is likely the most important factor in determining the composition and characteristics of the planets that formed. This is because the temperature affects the ability of solid particles to form and the types of chemical reactions that can occur. Different temperatures also favor the formation of different chemical compounds, such as metals or silicates, which can impact the final composition of the planets.

Question 9

The most probable theory for the solar system's formation is

Accepted Answer

The most widely accepted theory for the formation of the solar system is the nebular theory, which explains the formation of the Sun and planets from a cloud of gas and dust. According to this theory, the solar system started as a spinning disc of gas and dust called a solar nebula. As gravity caused the nebula to condense, it began to heat up and eventually caused the central part of the nebula to collapse and form the Sun. At the same time, smaller clumps of material called planetesimals began to form in the surrounding nebula. Over time, these planetesimals collided and stuck together, eventually forming the planets. This process is called accretion. The gas and dust that remained in the nebular disk eventually formed the rings, asteroids, and comets in the outer parts of the solar system.

Question 10

If a large cloud of gas and dust is initially rotating,and it begins to contract without losing any mass,it will rotate

Accepted Answer

According to the law of conservation of angular momentum, as the cloud of gas and dust contracts without losing any mass, its rotational speed must increase to conserve its angular momentum.

Question 11

The reason for the vast amount of hydrogen in the interior of Jupiter is probably that

Accepted Answer

The answer of The reason for the vast amount of...

Question 12

The most probable time sequence for the solar system's formation was that the

Accepted Answer

This is known as the nebular hypothesis, where the Sun formed from a collapsing cloud of gas and dust, and the planets and their moons formed from the leftover material. This theory is supported by evidence such as the similarities in composition of the Sun and the planets, the direction of planetary orbits, and the presence of asteroid belts and Kuiper Belt objects.

Question 13

What name is given to the concentration of mass that formed at the center of the solar nebula,eventually becoming the Sun?

Accepted Answer

The concentration of mass that formed at the center of the solar nebula, eventually becoming the Sun is called the Protosun.

Question 14

In order for the disk instability model to be able to account for the formation of the Jovian planets,

Accepted Answer

The disk instability model requires the gas in the nebular disk to be clumpy so that these clumps can start to contract and eventually form Jupiter-sized gas giants. Rocky material being confined completely to the inner part of the solar system (choice A) and gas being at a very high temperature (choice B) are not specifically required for this model to work, and the gas being mostly methane and ammonia (choice D) is not a necessary condition for the formation of Jovian planets.

Question 15

The early phases of planetary formation into protoplanets were characterized by

Accepted Answer

The early phases of planetary formation involved the slow accretion of small particles and dust by gravitational attraction and collision, which gradually formed larger bodies known as protoplanets. This process was aided by the presence of a protoplanetary disk of gas and dust surrounding the young star. It is important to note that while there were likely some collisions and impacts involved in this process, they were not as violent or shattering as option C suggests. Option B refers to earlier stages of star formation, and option D refers to the later stages of protoplanet formation when heating and gravitational collapse became more intense.

Question 16

What was the form of the material from which the solar system formed?

Accepted Answer

The prevailing theory of solar system formation is the nebular hypothesis, which states that the Sun and planets formed from a rotating cloud of gas and dust known as a nebula. This nebula was mostly made of hydrogen and helium gas, but it was also enriched in heavier elements from previous supernova explosions, which had scattered these elements throughout the galaxy. Therefore, choice A (a nebula made mostly of hydrogen and helium gas, but enriched in heavier elements from supernova explosions) is the best answer.

Question 17

The most probable process for the formation or acquisition of the Sun's planets is

Accepted Answer

The most accepted theory for the formation of the Sun's planets is the process of relatively slow growth of smaller objects by collisions and mutual gravitational attraction. This is known as the hypothesis of planetesimal accretion. Small grains in the protoplanetary disk come together by mutual gravitational attraction and form larger bodies known as planetesimals. These planetesimals then collide with each other and gravitationally attract each other to form larger and larger bodies, eventually forming the planets within the solar system.

Question 18

A T Tauri wind is

Accepted Answer

A T Tauri wind is a rapid expulsion of the tenuous outer layers of a young star. This wind is formed when the young star's strong magnetic fields interact with the surrounding protoplanetary disk, launching material away from the star. It is an important process in the early stages of star formation, as it can help clear away the disk material and slow down the rate of accretion onto the star.

Question 19

In describing the early solar system,we discuss solids and vapors but no liquids.Why do we believe liquids were absent?

Accepted Answer

The pressure in the solar nebula was too low to permit liquids to exist. In the early stages of the solar system, the low pressure conditions of the solar nebula meant that materials would sublimate directly from solid to gas without passing through a liquid phase.

Question 20

Which one of the following is NOT an example of the conservation of angular momentum?

Accepted Answer

The Moon keeping one face pointed toward Earth is an example of tidal locking, not a demonstration of the conservation of angular momentum. The other options (A, B, C) illustrate situations where angular momentum is conserved, leading to changes in rotational speed or orbital velocity as the distribution of mass changes or as objects move in their orbits.

Quiz 4: Exploring Our Evolving Solar System