Question 1

What is one way that astronomers have actually gotten an idea of the age of the surfaces of terrestrial planets other than the Earth?
A) looking at the colors different surfaces show
B) bringing back samples and run radioactive dating tests
C) counting craters
D) measuring the thickness of the atmosphere above each surface
E) looking in the instruction manual that comes with each planet

Accepted Answer

Astronomers can use the number of craters on a planet's surface to estimate its age. This is because over time, a planet's surface gets bombarded with small objects, like meteoroids, which leave behind craters. The more craters a surface has, the older it is thought to be. This method has been used to estimate the ages of surfaces on the Moon, Mars, and several of the moons of Jupiter and Saturn.

Question 2

The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call:
A) planetesimals
B) nebuloids
C) satellites
D) differentiated objects
E) jovians

Accepted Answer

The term used to describe the smaller pieces that eventually come together to form the major bodies in our solar system is planetesimals.

Question 3

Our best evidence and theoretical calculations indicate that the solar system began with a giant spinning system of gas and dust that scientists call:
A) the Titius-Bode cloud
B) the solar nebula
C) a planetesimal
D) the asteroid belt
E) the beltway

Accepted Answer

The solar system began as a giant spinning system of gas and dust known as the solar nebula, as supported by scientific evidence and theoretical calculations.

Question 4

In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its
A) radioactive ratio
B) parent-daughter criterion
C) half-life
D) geological activity
E) Tinder activity

Accepted Answer

The measure that scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its half-life. It is the time taken for half of the radioactive nuclei in a sample to decay.

Question 5

The inner planets are made mostly of rock and metal because:
A) lighter materials cannot orbit the Sun; they would fall in immediately
B) the Sun is made mostly of rock and metal and the inner planets are closest to the Sun
C) it was so hot where the inner planets formed that the lighter materials evaporated
D) Jupiter's large gravity immediately attracted all the lighter materials, and so there were few light atoms left by the time the inner planets were ready to form
E) this is an unsolved problem in astronomy

Accepted Answer

The inner planets formed close to the Sun where it was very hot, so lighter materials like hydrogen and helium evaporated, leaving behind mostly rock and metal.

Question 6

On Earth, we can get the age of various parts of our planet by finding rocks that contain radioactive atoms. Which other world do have a good number of rocks from to do this kind of age analysis?
A) Venus
B) The Moon
C) Halley's Comet
D) Jupiter
E) You can't fool me, there is no other world from which we have rocks

Accepted Answer

The Moon is the only option that has a good number of rocks that have been brought back to Earth by the Apollo missions. These rocks have been used to study the age of the Moon and the history of our solar system.

Question 7

In general, the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?
A) its atmosphere (whether it has one and how thick it is)
B) the number of large moons that are close to the planet
C) how fast the planet is spinning (the length of its day)
D) whether its core has a lot of iron in it
E) none of the above (only distance from the Sun affects a planet's temperature)

Accepted Answer

The atmosphere of a planet plays a significant role in determining its surface temperature. Greenhouse gases, such as carbon dioxide, trap heat and cause a planet to be warmer than it would be otherwise. Planets with thicker atmospheres also tend to have higher surface temperatures.

Question 8

In studying the surfaces of solid bodies in the solar system, astronomers have learned that the number of craters (per unit area):
A) is about the same on every world
B) is greater as you get closer to the Sun
C) is greater as you get further and further from the Sun
D) is roughly proportional to the age of the surface we are examining
E) follows no discernible rules or relationships at all

Accepted Answer

Craters on solid bodies in the solar system are caused by impacts with other objects. As such, the number of craters on a surface can give an indication of its age: the more craters, the older the surface. Therefore, the number of craters is roughly proportional to the age of the surface we are examining.

Question 9

The rate at which a collection of the same radioactive atoms will decay depends on:
A) the amount of radio waves falling on the material
B) the amount of light falling on the material
C) the temperature of the material
D) the size of the planet or moon on which the material is located
E) only on internal processes within the atoms; nothing external matters

Accepted Answer

The rate of radioactive decay is determined solely by internal processes within the atoms, specifically the stability of the nucleus and the probability of emitting radiation. External factors such as temperature, light, and radio waves will not affect the rate of decay. The size of the planet or moon may affect the way radiation emitted by the radioactive material is absorbed or detected, but it does not affect the rate at which the atoms decay.

Question 10

In a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villain has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg. for his weapon to work. After how much time will the weapon no longer be a threat?
A) just a little after 1 hr
B) just a little after 2 hrs
C) just a little after 4 hours
D) just a little after 16 hours
E) can't be determined from the information given

Accepted Answer

The half-life of the radioactive material is 1 hour, meaning the amount of material halves every hour. Starting with 4 kg, after 1 hour it would be 2 kg, and after 2 hours it would be 1 kg. Just after 2 hours, the amount would drop below 1 kg, making the weapon no longer a threat.

Question 11

One piece of evidence that can help astronomers sort out how the planets in our solar system formed is
A) discovering other galaxies of stars beyond the Milky Way
B) counting the number of moons around each planet in our own solar system
C) finding circumstellar disks of material around nearby stars
D) counting the craters on the surface of Jupiter, Saturn, Uranus, and Neptune
E) measuring variations in the amount of snowfall in northern Canada during this century

Accepted Answer

The presence of circumstellar disks around nearby stars can indicate the early stages of planet formation, as the disk of material eventually coalesces into planets. Observing these disks can provide clues about the conditions and processes involved in the formation of our own solar system. None of the other options are directly related to planet formation in our own solar system.

Question 12

On which planet (besides the Earth) do we still see a high level of geological activity on the surface today?
A) Jupiter
B) Mercury
C) Neptune
D) Venus
E) none of the above
Section 4.3: Dating Planetary Surfaces

Accepted Answer

Venus still shows a high level of geological activity on its surface today, including volcanic eruptions, lava flows, and rift valleys.

Question 13

A future interplanetary tourist whose parents kept him too warm as a baby asks for your help to find a "really cold place" in the solar system. Which of the following would be the coldest place to take him?
A) the Earth's polar regions
B) the moons of Neptune
C) the moons of Mars (which are captured asteroids)
D) Halley's Comet when it is closest to the Earth in its orbit
E) the deep atmosphere of Jupiter

Accepted Answer

The moons of Neptune, particularly Triton, have extremely low temperatures of around -235°C (-391°F) due to their distance from the sun and the thin atmosphere. This makes them the coldest place in the solar system that a tourist could potentially visit. The other options may have cold temperatures, but not as extreme as the moons of Neptune.

Question 14

Radioactive dating techniques have revealed that our Earth and Moon are approximately how old?
A) about 6,000 years
B) about 2 million years
C) about 100 million years
D) about 4.5 billion years
E) you can't fool me, we have no way of measuring ages as old as the Earth's
Section 4.4: Origin of the Solar System

Accepted Answer

Radioactive dating techniques have revealed that the Earth and Moon are approximately 4.5 billion years old.

Question 15

Which of the following places is most likely NOT to be differentiated?
A) a small asteroid
B) Earth
C) Jupiter
D) Venus, because it is so hot
E) Ganymede, the largest satellite in the solar system

Accepted Answer

Small asteroids are generally homogeneous and do not have enough gravity to produce layers or differentiation.

Question 16

On which of the planets (other than Earth) could a human being step out of a spacecraft and survive without any protective gear (special suit, oxygen tanks, etc)?
A) Venus
B) Mars
C) Jupiter
D) Neptune
E) you can't fool me; there is no other planet on which we could survive unprotected

Accepted Answer

No planet other than Earth in our solar system can support human life without protective gear due to extreme temperatures, lack of breathable atmosphere, or high radiation levels.

Quiz 7: Other Worlds: an Introduction to the Solar System

What is one way that astronomers have actually gotten an idea of the age of the surfaces of terrestrial planets other than the Earth?

The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call:

Our best evidence and theoretical calculations indicate that the solar system began with a giant spinning system of gas and dust that scientists call:

In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its

The inner planets are made mostly of rock and metal because:

On Earth, we can get the age of various parts of our planet by finding rocks that contain radioactive atoms. Which other world do have a good number of rocks from to do this kind of age analysis?

In general, the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?

In studying the surfaces of solid bodies in the solar system, astronomers have learned that the number of craters (per unit area) :

The rate at which a collection of the same radioactive atoms will decay depends on:

One piece of evidence that can help astronomers sort out how the planets in our solar system formed is

On which planet (besides the Earth) do we still see a high level of geological activity on the surface today?

A future interplanetary tourist whose parents kept him too warm as a baby asks for your help to find a "really cold place" in the solar system. Which of the following would be the coldest place to take him?

Radioactive dating techniques have revealed that our Earth and Moon are approximately how old?

Which of the following places is most likely NOT to be differentiated?

On which of the planets (other than Earth) could a human being step out of a spacecraft and survive without any protective gear (special suit, oxygen tanks, etc) ?