Question 1

Table 7-2 (in the text) describes the seven largest satellites in the solar system. From these data it can be seen that the presence of an atmosphere correlates with:
A)diameter. The largest satellites have atmospheres, the smaller ones do not.
B)mass. The more massive the satellite, the more likely the satellite is to have an atmosphere.
C)average density. The satellites with the larger average densities are more likely to have atmospheres.
D)None of the above is correct.

Accepted Answer

The answer of Table 7-2 (in the text) describes the...

Question 2

Comparing Earth's Moon to the rest of the solar system, which contains about 130 known satellites, it is found that the Moon is:
A)a typical satellite of about average size.
B)the largest satellite in the solar system.
C)the largest satellite in the inner part of the solar system.
D)larger than some planets, including Mercury and Mars.

Accepted Answer

The Moon is the largest satellite relative to its planet in the inner solar system, but not the largest overall—that title goes to Ganymede, a moon of Jupiter.

Question 3

How many moons in the solar system are larger than Earth's Moon? (See Table 7-2 of Universe, 11^th ed.) A)zero B)one C)two D)four

Accepted Answer

The answer of How many moons in the solar system...

Question 4

The wide absorption features in the optical spectrum of Titan's atmosphere (See Figure 7-3 of Universe, 11th ed.) are produced by: A)water vapor, H₂O. B)methane gas, CH₄. C)hydrogen gas, H₂. D)oxygen gas, O₂.

Accepted Answer

The wide absorption features in the optical spectrum of Titan's atmosphere are produced by methane gas. This is because Titan's atmosphere is primarily composed of nitrogen gas with some methane gas present, which absorbs certain wavelengths of light in the visible spectrum.

Question 5

How do spectra of reflection of sunlight from a planet's surface compare with the spectra produced when this reflected light passes through the planet's atmosphere?
A)The surface produces only emission lines, the atmosphere produces only absorption lines.
B)The surface produces only absorption lines, the atmosphere produces only emission lines.
C)The surface spectra contain broad absorption lines, the atmosphere contains sharp absorption lines.
D)The surface spectra contain sharp absorption lines, the atmosphere contains broad absorption lines.

Accepted Answer

The surface spectra contain broad absorption lines due to the variety of materials and conditions on the surface. The atmosphere, on the other hand, contains sharp absorption lines because the gases in the atmosphere absorb light at very specific wavelengths.

Question 6

The discovery of nitrogen gas (N₂) in the atmosphere of Titan was made by: A)direct sampling of the atmosphere by a probe as it descended to Titan's surface. B)ultraviolet spectroscopy from Earth. C)measurement of microwave emission from N₂ molecules by radio telescopes on Earth. D)infrared spectroscopy from the Cassini spacecraft.

Accepted Answer

The answer of The discovery of nitrogen gas (N₂) in...

Question 7

The composition of the solid surfaces of planets and satellites (moons) that do not have substantial atmospheres can be found by:
A)measuring the thermal emission from the surface at several wavelengths in the microwave and infrared regions of the spectrum.
B)comparing the spectrum of the sunlight reflected from the surface with the spectrum of direct sunlight from the Sun.
C)comparing very broad absorption features in their spectra with spectra of known substances on Earth.
D)measuring the wavelengths of narrow absorption lines in their spectra.

Accepted Answer

Comparing very broad absorption features in the spectra of planets and satellites with spectra of known substances on Earth is the best way to determine the composition of solid surfaces. This is because different elements and compounds absorb light at certain wavelengths, causing broad absorption features in their spectra. By comparing these absorption features with spectra of known substances on Earth, we can determine the composition of the solid surface. The other options (measuring thermal emission, comparing reflected sunlight, and measuring narrow absorption lines) are useful methods for studying planetary atmospheres, but they do not provide as much information about the composition of solid surfaces.

Question 8

How does spectroscopy help determine the composition of a planet's atmosphere?
A)Radiation emitted by the planet passes through the atmosphere on its way to Earth, and analysis of the resulting absorption spectrum gives clues to the atmosphere's composition.
B)Heat from the planet makes its atmosphere emit large amounts of radiation. Analysis of the resulting emission spectrum gives clues to the atmosphere's composition.
C)Light from the Sun passes through the planet's atmosphere before and after reflecting from the planet's surface. Analysis of the resulting absorption spectrum gives clues to the atmosphere's composition.
D)At present, the only way to determine the composition of a planet's atmosphere is to have a flyby spacecraft scoop up a sample and then analyze it with an on-board spectrometer.

Accepted Answer

The answer of How does spectroscopy help determine the composition...

Question 9

A laboratory on the surface of Earth makes a spectrum of radiation that originates at the Sun and reflects off a celestial body with an atmosphere such as Saturn's large satellite Titan. Which one of the following statements about the resulting spectrum is correct?
A)The reflection from the solid surface produces sharp spectral lines.
B)Earth's atmosphere contributes only very broad spectral features, not sharp lines, to the spectrum.
C)The atmosphere of the body can contribute sharp absorption lines to the spectrum.
D)There is no evidence in the spectrum of the solar origin of the radiation.

Accepted Answer

When radiation from the sun reflects off a celestial body with an atmosphere, the atmosphere can contribute sharp absorption lines to the spectrum. This is because the atoms and molecules in the atmosphere can absorb specific wavelengths of light, leaving dark absorption lines in the spectrum. These absorption lines can provide information about the composition and properties of the atmosphere. Option A is incorrect because reflections off solid surfaces do not typically produce sharp spectral lines. Option B is incorrect because Earth's atmosphere does contribute to the spectrum with broad features, but this is not the only contribution. Option D is incorrect because the solar origin of the radiation is evident in the spectrum.

Question 10

To an astronomer, the word "ice" can mean: A)water (H₂O), carbon dioxide (CO₂), methane (CH₄), or ammonia (NH₃). B)hydrogen (H₂), water (H₂O), carbon dioxide (CO₂), methane (CH₄), or ammonia (NH₃). C)only water (H₂O). D)water (H₂O) or carbon dioxide (CO₂).

Accepted Answer

To an astronomer, the word "ice" can refer to various types of frozen volatile substances found in space, including water, carbon dioxide, methane, and ammonia.

Question 11

If the atmosphere of a particular planet is at a temperature of 213 K (-60°C), then molecules of methane (CH₄) and molecules of carbon dioxide (CO₂) in this atmosphere have: A)different average speed and kinetic energy. B)the same average kinetic energy (but different average speed). C)the same average speed (but different average kinetic energy). D)the same average speed and kinetic energy.

Accepted Answer

At a given temperature, all gases have the same average kinetic energy, which is proportional to the temperature. Therefore, both methane and carbon dioxide molecules in the atmosphere will have the same average kinetic energy. However, their molecular masses are different, so they will have different average speeds. This means that option B is correct, as the molecules have the same average kinetic energy but different average speeds.

Question 12

A nitrogen molecule (N₂) has a mass of 4.7 × 10^-26 kg, and a carbon dioxide molecule (CO₂) has a mass of 7.3 × 10^-26 kg. On a day when the temperature is 18°C (64°F), the N₂ molecules will have a: A)greater average kinetic energy and greater average speed than the CO₂ molecules. B)smaller average kinetic energy but greater average speed than the CO₂ molecules. C)smaller average speed than the CO₂ molecules but the same average kinetic energy. D)greater average speed than the CO₂ molecules but the same average kinetic energy.

Accepted Answer

At a given temperature, all gases have the same average kinetic energy due to the kinetic theory of gases. However, lighter molecules, like nitrogen in this case, will have a greater average speed than heavier molecules like carbon dioxide, because kinetic energy is also a function of mass and velocity.

Question 13

Each type of molecule has the same average kinetic energy in a planetary atmosphere. As a result (and knowing that an oxygen [O₂] molecule has twice the mass of a methane [CH₄] molecule), we can say that in this atmosphere the average speed of an oxygen molecule is: A)1.4 times less than that of a methane molecule. B)half that of a methane molecule. C)twice that of a methane molecule. D)1.4 times greater than that of a methane molecule.

Accepted Answer

The average kinetic energy of a molecule is given by $ \frac{1}{2}mv^2 $, where $ m $ is the mass and $ v $ is the speed of the molecule. Since the kinetic energy is the same for both types of molecules and the mass of an oxygen molecule is twice that of a methane molecule, the speed of an oxygen molecule must be $ \sqrt{1/2} $ times that of a methane molecule, which is approximately 1.4 times less.

Question 14

An oxygen (O₂) molecule has twice the mass of a methane (CH₄) molecule. In a planet's atmosphere at some particular temperature, the average kinetic energy of an oxygen molecule is: A)the same as that of a methane molecule (that is, all molecules have the same average kinetic energy at the same temperature). B)1.4 times greater than that of a methane molecule (that is, the average kinetic energy increases in proportion to the square root of the mass). C)4 times greater than that of a methane molecule (that is, the average kinetic energy increases in proportion to the square of the mass). D)twice that of a methane molecule (that is, the average kinetic energy increases in the same proportion as the mass).

Accepted Answer

The average kinetic energy of molecules in a gas is determined by the temperature of the gas, not by the mass of the molecules. Therefore, at the same temperature, all molecules, regardless of their mass, have the same average kinetic energy.

Question 15

The average speed of methane molecules (CH₄, molecular mass = 2.66 × 10^-26 kg) in the atmosphere of Neptune (temperature = 63 K = -210°C) is: A)313 m/s. B)327,000 m/s. C)572 m/s. D)98,000 m/s.

Accepted Answer

The average speed of gas molecules can be calculated using the formula for the root mean square speed, $v_{rms} = \sqrt{\frac{3kT}{m}}$, where $k$ is the Boltzmann constant ($1.38 \times 10^{-23} \, \text{J/K}$), $T$ is the temperature in Kelvin, and $m$ is the mass of one molecule of the gas. Substituting the given values for methane ($m = 2.66 \times 10^{-26} \, \text{kg}$, $T = 63 \, \text{K}$), we find that the average speed is closest to 313 m/s, making option A correct.

Question 16

Most of the ammonia on Jupiter is in the form of a:
A)gas.
B)liquid.
C)solid.
D)plasma.

Accepted Answer

The answer of Most of the ammonia on Jupiter is...

Question 17

On Mars, the temperature can reach 290 K and the escape speed is 5.0 km/sec. What is the average speed of a carbon dioxide molecule (mass = 7.31 × 10^-26 kg) at this temperature, and what can you say about the retention of carbon dioxide on Mars? A)The average speed is 0.4 km/sec, so Mars should retain its carbon dioxide. B)The average speed is 0.4 km/sec, so Mars should lose its carbon dioxide. C)The average speed is 1.9 km/sec, so Mars should retain its carbon dioxide. D)The average speed is 1.9 km/sec, so Mars should lose its carbon dioxide.

Accepted Answer

The average speed of a carbon dioxide molecule at 290 K can be calculated using the formula for the root-mean-square speed, $v_{rms} = \sqrt{\frac{3kT}{m}}$, where $k$ is the Boltzmann constant ($1.38 \times 10^{-23} \, \text{J/K}$), $T$ is the temperature in Kelvin, and $m$ is the mass of a molecule in kilograms. Plugging in the values, we find that the average speed is significantly lower than the escape speed of Mars (5.0 km/sec), indicating that Mars should retain its carbon dioxide.

Question 18

The average speed of hydrogen molecules (H₂) in Earth's atmosphere is below the calculated escape speed from Earth (11.2 km/s). So, is hydrogen gas retained in Earth's atmosphere? A)Yes. Under these conditions H₂ must be retained. B)No. Escape speed depends on the mass of the escaping object. Hydrogen is the lightest molecule, thus its escape speed is well below 11.2 km/s. C)No. Escape speed depends on the mass of the escaping object. Hydrogen is the lightest molecule, thus its escape speed is well above 11.2 km/s. D)No. While the average speed of H₂ is below the escape speed, there will be some H₂ molecules with speeds above escape speed-and these will escape.

Accepted Answer

The distribution of molecular speeds in a gas means that some molecules move faster than the average speed. For hydrogen in Earth's atmosphere, even though the average speed is below the escape velocity, some molecules will exceed this speed and escape into space.

Question 19

The asteroid Vesta, located in the main asteroid belt between the orbits of Mars and Jupiter, is spherical in shape with a radius of 265 km and a mass of 3.0 × 10²⁰ kg. What is the minimum speed at which you could propel yourself upward and not fall back down? A)285,000 m/s B)0.28 m/s C)388 m/s D)534 m/s

Accepted Answer

The minimum speed needed to escape from the gravitational pull of an object can be found using the equation:
v = sqrt(2GM/r)
where v is the minimum speed, G is the gravitational constant, M is the mass of the object, and r is the distance from the center of the object.

Plugging in the values for Vesta, we get:
v = sqrt(2 * 6.67 × 10^-11 N(m/kg)^2 * 3.0 × 10^20 kg / 265,000 m)
v = 387.9 m/s

Rounding to the nearest whole number, the minimum speed needed to escape from Vesta is 388 m/s, so the correct answer is C.

Question 20

What relationship must exist between a certain molecule's average speed, v, in a planetary atmosphere and the escape velocity, V_esc, from the planet's surface for this particular molecular species to be retained by the planet? A)v should not exceed V_esc. B)v must be less than about 6 × V_esc. C)v must be less than about 1/6 V_esc. D)v should not exceed 2 × V_esc.

Accepted Answer

For a molecule to be retained by a planet, its average speed must be significantly less than the planet's escape velocity. The rule of thumb is that the molecule's average speed should be less than about 1/6 of the escape velocity. This ensures that only a small fraction of the molecules in the high-speed tail of the Maxwell-Boltzmann distribution have enough speed to escape the planet's gravitational pull.

Quiz 7: Comparative Planetology I: Our Solar System

Table 7-2 (in the text) describes the seven largest satellites in the solar system. From these data it can be seen that the presence of an atmosphere correlates with:

Comparing Earth's Moon to the rest of the solar system, which contains about 130 known satellites, it is found that the Moon is:

How many moons in the solar system are larger than Earth's Moon? (See Table 7-2 of Universe, 11^th ed.)

The wide absorption features in the optical spectrum of Titan's atmosphere (See Figure 7-3 of Universe, 11th ed.) are produced by:

How do spectra of reflection of sunlight from a planet's surface compare with the spectra produced when this reflected light passes through the planet's atmosphere?

The discovery of nitrogen gas (N₂) in the atmosphere of Titan was made by:

The composition of the solid surfaces of planets and satellites (moons) that do not have substantial atmospheres can be found by:

How does spectroscopy help determine the composition of a planet's atmosphere?

A laboratory on the surface of Earth makes a spectrum of radiation that originates at the Sun and reflects off a celestial body with an atmosphere such as Saturn's large satellite Titan. Which one of the following statements about the resulting spectrum is correct?

To an astronomer, the word "ice" can mean:

If the atmosphere of a particular planet is at a temperature of 213 K (-60°C) , then molecules of methane (CH₄) and molecules of carbon dioxide (CO₂) in this atmosphere have:

A nitrogen molecule (N₂) has a mass of 4.7 × 10^-26 kg, and a carbon dioxide molecule (CO₂) has a mass of 7.3 × 10^-26 kg. On a day when the temperature is 18°C (64°F) , the N₂ molecules will have a:

Each type of molecule has the same average kinetic energy in a planetary atmosphere. As a result (and knowing that an oxygen [O₂] molecule has twice the mass of a methane [CH₄] molecule) , we can say that in this atmosphere the average speed of an oxygen molecule is:

An oxygen (O₂) molecule has twice the mass of a methane (CH₄) molecule. In a planet's atmosphere at some particular temperature, the average kinetic energy of an oxygen molecule is:

The average speed of methane molecules (CH₄, molecular mass = 2.66 × 10^-26 kg) in the atmosphere of Neptune (temperature = 63 K = -210°C) is:

Most of the ammonia on Jupiter is in the form of a:

On Mars, the temperature can reach 290 K and the escape speed is 5.0 km/sec. What is the average speed of a carbon dioxide molecule (mass = 7.31 × 10^-26 kg) at this temperature, and what can you say about the retention of carbon dioxide on Mars?

The average speed of hydrogen molecules (H₂) in Earth's atmosphere is below the calculated escape speed from Earth (11.2 km/s) . So, is hydrogen gas retained in Earth's atmosphere?

The asteroid Vesta, located in the main asteroid belt between the orbits of Mars and Jupiter, is spherical in shape with a radius of 265 km and a mass of 3.0 × 10²⁰ kg. What is the minimum speed at which you could propel yourself upward and not fall back down?

What relationship must exist between a certain molecule's average speed, v, in a planetary atmosphere and the escape velocity, V_esc, from the planet's surface for this particular molecular species to be retained by the planet?

Quiz 7: Comparative Planetology I: Our Solar System

Table 7-2 (in the text) describes the seven largest satellites in the solar system. From these data it can be seen that the presence of an atmosphere correlates with:

Comparing Earth's Moon to the rest of the solar system, which contains about 130 known satellites, it is found that the Moon is:

How many moons in the solar system are larger than Earth's Moon? (See Table 7-2 of Universe, 11th ed.) ​ ​

The wide absorption features in the optical spectrum of Titan's atmosphere (See Figure 7-3 of Universe, 11th ed.) are produced by: ​ ​

How do spectra of reflection of sunlight from a planet's surface compare with the spectra produced when this reflected light passes through the planet's atmosphere?

The discovery of nitrogen gas (N2) in the atmosphere of Titan was made by:

The composition of the solid surfaces of planets and satellites (moons) that do not have substantial atmospheres can be found by:

How does spectroscopy help determine the composition of a planet's atmosphere?

A laboratory on the surface of Earth makes a spectrum of radiation that originates at the Sun and reflects off a celestial body with an atmosphere such as Saturn's large satellite Titan. Which one of the following statements about the resulting spectrum is correct?

To an astronomer, the word "ice" can mean:

If the atmosphere of a particular planet is at a temperature of 213 K (-60°C) , then molecules of methane (CH4) and molecules of carbon dioxide (CO2) in this atmosphere have:

A nitrogen molecule (N2) has a mass of 4.7 × 10-26 kg, and a carbon dioxide molecule (CO2) has a mass of 7.3 × 10-26 kg. On a day when the temperature is 18°C (64°F) , the N2 molecules will have a:

Each type of molecule has the same average kinetic energy in a planetary atmosphere. As a result (and knowing that an oxygen [O2] molecule has twice the mass of a methane [CH4] molecule) , we can say that in this atmosphere the average speed of an oxygen molecule is:

An oxygen (O2) molecule has twice the mass of a methane (CH4) molecule. In a planet's atmosphere at some particular temperature, the average kinetic energy of an oxygen molecule is:

The average speed of methane molecules (CH4, molecular mass = 2.66 × 10-26 kg) in the atmosphere of Neptune (temperature = 63 K = -210°C) is: