Question 1

The diagram below shows the radioactive decay of cesium (135Cs). What is the half-life of 135Cs?

Accepted Answer

3 million years

Question 2

How do the motions of the sun and planets reflect the disk shape of the solar nebula?

Accepted Answer

The motions of the sun and planets within our solar system are a direct consequence of the solar system's origins from a rotating disk-shaped cloud of gas and dust known as the solar nebula. This nebula collapsed under its own gravity, which led to the formation of the sun and the planets. The disk shape of the solar nebula and the motions of the bodies within the solar system are closely related through the following aspects:

1. Conservation of Angular Momentum: As the solar nebula contracted, it spun faster due to the conservation of angular momentum. This is similar to how a figure skater spins faster when they pull their arms in. The rotation caused the nebula to flatten into a disk shape, with most of the material moving in the same direction around the center where the sun would eventually form.

2. Formation of the Sun and Planets: The sun formed at the center of the disk, where the density of material was highest and gravitational forces caused the hydrogen and helium to fuse, initiating nuclear fusion. Around the sun, the remaining material in the disk began to coalesce into planetesimals, which eventually formed the planets, moons, asteroids, and other bodies.

3. Coplanar Orbits: Because the planets formed within this rotating disk, they naturally ended up orbiting in the same plane, known as the ecliptic plane. This is why the planets of the solar system generally have orbits that are relatively flat and aligned with one another, reflecting the original disk shape of the solar nebula.

4. Prograde Motion: The direction of the rotation of the solar nebula also determined the direction of the rotation of the planets and their orbits around the sun. Most planets in the solar system rotate on their axes and revolve around the sun in the same direction that the solar nebula was spinning, which is counterclockwise when viewed from above the north pole of the sun. This common direction of motion is known as prograde motion.

5. Angular Momentum Distribution: The sun contains the majority of the mass of the solar system but only a small fraction of its angular momentum. The planets, being spread out over a larger area and moving at significant velocities, carry most of the solar system's angular momentum. This distribution reflects the initial conditions of the spinning solar nebula and the process of angular momentum transfer during the formation of the solar system.

In summary, the disk shape of the solar nebula is reflected in the coplanar orbits of the planets, their prograde motion, and the overall distribution of angular momentum within the solar system. These characteristics are a result of the physical laws governing the collapse and rotation of the solar nebula, leading to the structured and organized system we observe today.

Question 3

The asteroid belt is found between which two planets' orbits?

Accepted Answer

A)  Earth and Mars 
B)  Mars and Jupiter 
C)  Jupiter and Saturn 
D)  Venus and Earth 
A)  Earth and Mars 
B)  Mars and Jupiter 
C)  Jupiter and Saturn 
D)  Venus and Earth B

Question 4

The hydrogen and helium in our solar system were created from subatomic particles about ______ years ago.

Accepted Answer

A)  14 billion 
B)  10.5 billion 
C)  7.0 billion 
D)  4.5 billion 
A)  14 billion 
B)  10.5 billion 
C)  7.0 billion 
D)  4.5 billion

Question 5

The present motions of the planets were inherited from the rotation of the solar nebula.

Accepted Answer

A) True 
 B)False

Question 6

Which one of the following IS a characteristic of Jovian planets?

Accepted Answer

A)  low average density 
B)  orbits inside the asteroids 
C)  craters in old surfaces 
D)  small diameters 
E)  very few satellites 
A)  low average density 
B)  orbits inside the asteroids 
C)  craters in old surfaces 
D)  small diameters 
E)  very few satellites

Question 7

Why are more massive planets circling stars easier to detect than low-mass planets?

Accepted Answer

The answer of Why are more massive planets circling stars...

Question 8

Massive planets create ____________________ Doppler shifts of their stars than lower-mass planets.

Accepted Answer

The answer of Massive planets create ____________________ Doppler shifts of...

Question 9

Which one of the following IS NOT a characteristic of terrestrial planets?

Accepted Answer

A)  low average density 
B)  orbits inside the asteroids 
C)  craters in old surfaces 
D)  small diameters 
E)  very few satellites 
A)  low average density 
B)  orbits inside the asteroids 
C)  craters in old surfaces 
D)  small diameters 
E)  very few satellites

Question 10

One common technique used to discover the presence of an extrasolar planet around a star is to detect how they tug their stars about, creating small Doppler shifts in the stars' spectra.

Accepted Answer

A) True 
 B)False

Question 11

Part of the current atmosphere of Earth is believed to be

Accepted Answer

A)  the remnants of the original hydrogen and helium gas from the solar nebula attracted by the protoplanet. 
B)  the result of the melting and vaporizing of the glaciers from the last ice age. 
C)  composed primarily of hydrogen and helium. 
D)  composed of gases that were outgassed from the heated rocks sometime after the planet formed. 
E)  the result of a collision between the sun and another star. 
A)  the remnants of the original hydrogen and helium gas from the solar nebula attracted by the protoplanet. 
B)  the result of the melting and vaporizing of the glaciers from the last ice age. 
C)  composed primarily of hydrogen and helium. 
D)  composed of gases that were outgassed from the heated rocks sometime after the planet formed. 
E)  the result of a collision between the sun and another star.

Question 12

A newly formed planet or large asteroid becomes molten due to

Accepted Answer

A)  the last infalling objects. 
B)  decay of radioactive element isotopes. 
C)  both of the above. 
D)  none of the above. Newly formed planets remain solid inside. 
A)  the last infalling objects. 
B)  decay of radioactive element isotopes. 
C)  both of the above. 
D)  none of the above. Newly formed planets remain solid inside.

Question 13

____ pushed gas and dust particles out of the solar nebula by the light from the sun.

Accepted Answer

A)  Radiation pressure 
B)  Outgassing 
C)  Condensation 
D)  Accretion 
E)  Differentiation 
A)  Radiation pressure 
B)  Outgassing 
C)  Condensation 
D)  Accretion 
E)  Differentiation

Question 14

The Jovian problem refers to

Accepted Answer

A)  the high speed with which the Jovian planets rotate on their axes. 
B)  the large number of satellites that orbit each Jovian planet. 
C)  the existence of rings around the Jovian planets. 
D)  the excess heat radiated by the larger of the Jovian planets. 
E)  the apparently short period of time that disks exist around stars from which Jovian planets can form. 
A)  the high speed with which the Jovian planets rotate on their axes. 
B)  the large number of satellites that orbit each Jovian planet. 
C)  the existence of rings around the Jovian planets. 
D)  the excess heat radiated by the larger of the Jovian planets. 
E)  the apparently short period of time that disks exist around stars from which Jovian planets can form.

Question 15

Accretion is

Accepted Answer

A)  the adding of material to an object an atom or molecule at a time. 
B)  the adding of material to an object by collection of solid particles. 
C)  the release of gas from rocks as they are heated. 
D)  the largest of the Galilean satellites. 
E)  caused by the bombardment of the solar wind. 
A)  the adding of material to an object an atom or molecule at a time. 
B)  the adding of material to an object by collection of solid particles. 
C)  the release of gas from rocks as they are heated. 
D)  the largest of the Galilean satellites. 
E)  caused by the bombardment of the solar wind.

Question 16

If a star is found with five planets orbiting it, and a process like that described in the solar nebula theory formed the planets, which of the planets would be expected to have the greatest uncompressed density?

Accepted Answer

A)  The one farthest from the star. 
B)  The one with the greatest mass. 
C)  The one with the greatest radius. 
D)  The one closest to the star. 
E)  The one that has liquid water on its surface. 
A)  The one farthest from the star. 
B)  The one with the greatest mass. 
C)  The one with the greatest radius. 
D)  The one closest to the star. 
E)  The one that has liquid water on its surface.

Question 17

Venus is often called Earth's sister planet because it is similar to the Earth in terms of

Accepted Answer

A)  mass. 
B)  size. 
C)  density. 
D)  all of the above. 
A)  mass. 
B)  size. 
C)  density. 
D)  all of the above.

Question 18

A(n) ____ is a solar-system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere and does not survive to reach the surface.

Accepted Answer

A)  asteroid 
B)  meteor 
C)  comet 
D)  meteoroid 
E)  planetesimal 
A)  asteroid 
B)  meteor 
C)  comet 
D)  meteoroid 
E)  planetesimal

Question 19

How is the presence of space debris accounted for by solar system models?

Accepted Answer

A)  Space debris is left over material from the early solar system that never formed into a planet. 
B)  Space debris was formed by the collision of objects after the planets formed. 
C)  Space debris is material that existed in our region of space before the sun formed. 
D)  both a and b 
E)  all of the above 
A)  Space debris is left over material from the early solar system that never formed into a planet. 
B)  Space debris was formed by the collision of objects after the planets formed. 
C)  Space debris is material that existed in our region of space before the sun formed. 
D)  both a and b 
E)  all of the above

Question 20

What observation made of other stars seems to suggest the solar nebula theory is correct?

Accepted Answer

A)  Stars are found to exist more often in binaries than by themselves. 
B)  Protostars are seen to radiate much of their light at infrared wavelengths. 
C)  Nearby stars tend to be low-mass red dwarfs. 
D)  Young stars are found to have hot disks that surround them. 
A)  Stars are found to exist more often in binaries than by themselves. 
B)  Protostars are seen to radiate much of their light at infrared wavelengths. 
C)  Nearby stars tend to be low-mass red dwarfs. 
D)  Young stars are found to have hot disks that surround them.

The diagram below shows the radioactive decay of cesium (¹³⁵Cs). What is the half-life of ¹³⁵Cs?

How do the motions of the sun and planets reflect the disk shape of the solar nebula?

The asteroid belt is found between which two planets' orbits?

The hydrogen and helium in our solar system were created from subatomic particles about ______ years ago.

The present motions of the planets were inherited from the rotation of the solar nebula.

Which one of the following IS a characteristic of Jovian planets?

Why are more massive planets circling stars easier to detect than low-mass planets?

Massive planets create ____________________ Doppler shifts of their stars than lower-mass planets.

Which one of the following IS NOT a characteristic of terrestrial planets?

One common technique used to discover the presence of an extrasolar planet around a star is to detect how they tug their stars about, creating small Doppler shifts in the stars' spectra.

Part of the current atmosphere of Earth is believed to be

A newly formed planet or large asteroid becomes molten due to

____ pushed gas and dust particles out of the solar nebula by the light from the sun.

The Jovian problem refers to

Accretion is

If a star is found with five planets orbiting it, and a process like that described in the solar nebula theory formed the planets, which of the planets would be expected to have the greatest uncompressed density?

Venus is often called Earth's sister planet because it is similar to the Earth in terms of

A(n) ____ is a solar-system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere and does not survive to reach the surface.

How is the presence of space debris accounted for by solar system models?

What observation made of other stars seems to suggest the solar nebula theory is correct?

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies: Normal and Active

Modern Cosmology

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters

Exam 15: The Origin of the Solar System

The diagram below shows the radioactive decay of cesium (135Cs). What is the half-life of 135Cs?

How do the motions of the sun and planets reflect the disk shape of the solar nebula?

The asteroid belt is found between which two planets' orbits?

The hydrogen and helium in our solar system were created from subatomic particles about ______ years ago.

The present motions of the planets were inherited from the rotation of the solar nebula.

Which one of the following IS a characteristic of Jovian planets?

Why are more massive planets circling stars easier to detect than low-mass planets?

Massive planets create ____________________ Doppler shifts of their stars than lower-mass planets.

Which one of the following IS NOT a characteristic of terrestrial planets?

One common technique used to discover the presence of an extrasolar planet around a star is to detect how they tug their stars about, creating small Doppler shifts in the stars' spectra.

Part of the current atmosphere of Earth is believed to be

A newly formed planet or large asteroid becomes molten due to

____ pushed gas and dust particles out of the solar nebula by the light from the sun.

The Jovian problem refers to

Accretion is

If a star is found with five planets orbiting it, and a process like that described in the solar nebula theory formed the planets, which of the planets would be expected to have the greatest uncompressed density?

Venus is often called Earth's sister planet because it is similar to the Earth in terms of

A(n) ____ is a solar-system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere and does not survive to reach the surface.

How is the presence of space debris accounted for by solar system models?

What observation made of other stars seems to suggest the solar nebula theory is correct?

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies: Normal and Active

Modern Cosmology

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters

The diagram below shows the radioactive decay of cesium (¹³⁵Cs). What is the half-life of ¹³⁵Cs?