Question 1

Which of the following planets does NOT have an atmosphere?
A) Earth
B) Venus
C) Jupiter
D) Neptune
E) you can't fool me: all of the above have an atmosphere

Accepted Answer

All of the planets listed (Earth, Venus, Jupiter, Neptune) have atmospheres, making option E correct. Earth's atmosphere is composed of nitrogen, oxygen, and other gases; Venus has a thick atmosphere of carbon dioxide with clouds of sulfuric acid; Jupiter, being a gas giant, has a massive atmosphere primarily of hydrogen and helium; and Neptune also has an atmosphere, mainly of hydrogen, helium, and methane.

Question 2

The first technique that allowed astronomers to find exoplanets involved:
A) photographing the planets using infrared waves
B) looking for the decrease of light from the star during a transit of the planet across its disk
C) sending a very small spacecraft to the exoplanet to take close-up images
D) measuring changes in the radial velocity (Doppler shift) of the star caused by the pull of orbiting planets
E) simply taking a visible light photo of the planet around the nearest star; it wasn't that hard

Accepted Answer

The first technique that allowed astronomers to find exoplanets was measuring changes in the radial velocity (Doppler shift) of the star caused by the pull of orbiting planets. This technique became known as the radial velocity method or the Doppler method. By observing how the spectrum of a star changes over time, researchers can detect the wobble of a star caused by the gravitational pull of an exoplanet.

Question 3

A type of planet that our surveys of exoplanets are revealing around other stars, but we don't have any examples of around the Sun are:
A) terrestrial planets
B) jovian (giant) planets
C) Super-Earth's
D) dwarf planets
E) you can't fool me, we have examples in the solar system of all the types of planets our exoplanet surveys are revealing

Accepted Answer

Exoplanet surveys are revealing the existence of a type of planet called Super-Earths, which are larger than Earth but smaller than Neptune. While our solar system doesn't have an example of this type of planet, scientists believe they could be common throughout the universe.

Question 4

One of the best proofs that our theory of how the solar system formed is correct is that astronomers now observe
A) Pluto's orbit, which is not in the plane (or disk) that the other planets orbit in
B) disks around other stars which show evidence of gaps where planets may be forming
C) planets that are called "hot Jupiters"
D) no water in the inner solar system
E) UFO's with alien astronomy textbooks inside, discussing the same theories

Accepted Answer

The presence of disks around other stars which show evidence of gaps where planets may be forming is a strong indication that our theory of planet formation in a disk of gas and dust is correct. This supports the idea that our own solar system formed in a similar way.

Question 5

Which planet in the solar system rotates the most slowly (has the longest "day")?
A) Venus
B) Uranus
C) Earth
D) Jupiter
E) Pluto

Accepted Answer

Venus has the slowest rotation period of any planet in the Solar System, with its day lasting longer than its orbit around the Sun. It takes Venus 243 Earth days to rotate once on its axis.

Question 6

Of the following planets which has NO satellites (moons)?
A) Earth
B) Venus
C) Jupiter
D) Pluto
E) Neptune

Accepted Answer

Venus is the only planet among the given options that has no natural satellites (moons).

Question 7

The telescope in space that allowed astronomers to find thousands of exoplanets and exoplanet candidates by making very careful measurements during a planet transit was called:
A) Kepler
B) Voyager
C) Transitor
D) New Horizons
E) InSight

Accepted Answer

The telescope in space that allowed astronomers to find thousands of exoplanets and exoplanet candidates by making very careful measurements during a planet transit was called Kepler.

Question 8

Which planet in the solar system has the longest year (orbits the most slowly)?
A) Mercury
B) Uranus
C) Earth
D) Jupiter
E) Neptune

Accepted Answer

Neptune has the longest year, with a period of about 165 Earth years.

Question 9

At the beginning of the solar system's history, a ready supply of proto-planets or mini-planets crashed into the developing planets and each other - something astronomers call the "era of giant impacts." How long do astronomers estimate this era lasted?
A) only a few dozen years - it was over very quickly
B) about 100 million years (0.1 billion)
C) about two billion years
D) about four billion years (it only ended about half a billion years ago)
E) that era is not finished yet - giant impacts are still happening all over the solar system

Accepted Answer

Astronomers estimate that the "era of giant impacts" lasted about 100 million years (0.1 billion).

Question 10

One of the most perplexing issues raised by the discovery of thousands of exoplanets is the existence of "hot Jupiters" - planets with the masses and compositions of Jupiter, but orbiting closer to their stars than Mercury does in our solar system. What is our best idea currently about how such "hot Jupiters" came to be?
A) each hot Jupiter came directly out of the star it now orbits and must be made of the exact same material at only slightly lower temperatures
B) hot Jupiters formed by the collision and merger of many terrestrial planets - these collisions heated them up
C) hot Jupiters formed in an asteroid belt and are made of countless asteroids that are hot
D) hot Jupiters formed further out in their star system, and then migrated inward somehow
E) hot Jupiters are artificial; they were made by super-advanced alien beings to make the universe more interesting
Section 14.5: Planetary Evolution

Accepted Answer

The most widely accepted theory for the formation of hot Jupiters is that they formed further out in their star system, beyond the "snow line" where it was cool enough for water and other volatile substances to freeze into solid particles. This allowed the planets to grow larger and more massive, until their gravity was strong enough to pull in surrounding gas and form a gas giant. However, something caused these planets to migrate inward towards their star, perhaps due to interactions with other planets in the system, or through gravitational interaction with their star's disk of gas and dust. This migration could have caused the planets to reach their current, much closer orbits.

Question 11

For solid rocky worlds, a general rule is
A) the larger the world, the closer it is to the Sun
B) the smaller the world, the more likely it is to have an atmosphere
C) the larger the world, the slower it cools off and the more it will keep its internal heat
D) the smaller the world, the more likely it is to have a moon or moons
E) the shorter a world's year (time to orbit the Sun), the more likely it is to harbor life

Accepted Answer

This is because the larger a solid rocky world is, the more energy it has due to its greater mass, and energy is lost slower than by smaller bodies. This means it cools off more slowly and retains its internal heat for a longer period of time.

Question 12

A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that
A) those in the inner solar system were much larger than those in the outer solar system
B) those in the outer solar system included far more metal and rock, and thus the outer planets could be denser
C) those in the outer solar system were in a place where ice, not just rock, condensed and thus could grow larger
D) those in the outer solar system did not have enough planetesimals nearby
E) you can't fool me, there were no differences between the inner and outer protoplanets; only the planets that finally formed are different.
Section 14.3: Comparison with Other Planetary Systems

Accepted Answer

The difference between the protoplanets in the outer and inner solar system was that those in the outer solar system were able to grow larger because they were in a region where ice could condense in addition to rock. This allowed for the formation of larger protoplanets and ultimately, larger planets.

Question 13

The atmosphere of Venus is mostly carbon dioxide, and the atmosphere of the Earth has water vapor. Why are these two gases absent in the atmosphere of the satellite around Saturn called Titan?
A) Titan's atmosphere was captured from the ring system of Saturn, and thus consists of small ice crystals
B) The energetic particles in the magnetosphere of Saturn have collided with and knocked away all the lighter gases in the atmosphere of Titan
C) There are life-forms on the surface of Titan which absorb carbon dioxide and water vapor as part of their life processes
D) Titan is so cold that carbon dioxide and water vapor freeze out
E) There is a runaway greenhouse effect on Titan
Extra: Some Review Questions Covering the Entire Solar System

Accepted Answer

Titan's atmosphere is mostly composed of nitrogen and methane, which are both gases that can exist in their gaseous form at Titan's cold temperatures. However, carbon dioxide and water vapor are not present because they freeze out and form ice particles in Titan's atmosphere due to the low temperatures.

Question 14

Astronomers now believe that the differences in composition among the planets reflect what characteristic in the early solar system
A) orbital speed
B) temperature
C) whether or not a planet had rings
D) the age of the material
E) none of the above

Accepted Answer

The temperature of the early solar system played a significant role in determining the composition of each planet. Higher temperature zones closer to the sun contained materials that were evaporated or melted, while cooler zones further away retained more solid materials. This resulted in a pattern where the inner planets (Mercury, Venus, Earth, and Mars) are primarily made up of rock and metal, while the outer planets (Jupiter, Saturn, Uranus, and Neptune) are mostly made up of gas and ice.

Question 15

Many worlds in the solar system show extensive impact cratering, dating back billions of years. Which of the following worlds does NOT show such cratering?
A) Our Moon
B) Callisto
C) Mercury
D) Saturn
E) Mars

Accepted Answer

Saturn does not show extensive impact cratering as it is a gas giant planet and does not have a solid surface.

Question 16

One of the best ways to learn more about a world is to have samples from its surface to analyze in our laboratories. From which of the following worlds do we NOT yet have a sample to analyze here on Earth?
A) Earth
B) the Moon
C) Mars
D) Venus
E) the asteroid Vesta

Accepted Answer

As of my last update in 2023, we have samples from Earth, the Moon, Mars (through meteorites), and the asteroid Vesta (also through meteorites). However, we have not yet collected or received samples from Venus for analysis on Earth.

Question 17

Which of these worlds is the most active geologically?
A) Venus
B) Mars
C) Mercury
D) the Moon
E) all of the above are equally active these days

Accepted Answer

Venus is the most active geologically, with frequent volcanic eruptions and evidence of tectonic activity. Mars and Mercury also show some signs of geological activity, but not to the same extent as Venus. The Moon is relatively inactive compared to the other options.

Question 18

Which of the following is NOT a way that Jovian planets can be distinguished from terrestrial planets?
A) their average density is lower
B) they are farther away from the Sun
C) they include much more gas and liquid
D) they are larger
E) they have many more craters from collisions that happened early in solar system history

Accepted Answer

The presence of many craters is a characteristic of terrestrial planets, not Jovian planets. Jovian planets are distinguished by their lower density, larger size, greater distance from the Sun, and inclusion of much more gas and liquid.

Question 19

The reason that Olympus Mons, the tallest mountain on Mars, is taller than Mount Everest (the tallest mountain on Earth) is that:
A) the gravity on Mars is less, so a larger mass can support itself against its own weight
B) Mars has a much larger molten core than the Earth
C) there are no continental plates that move sideways on Mars, while there are such sliding motions on Earth
D) the Earth's Moon has a much stronger pull than the moons of Mars
E) more than one of the above

Accepted Answer

The correct answers are A and C. Olympus Mons is taller than Mount Everest partly because the gravity on Mars is less than Earth's, allowing larger masses to support themselves against their own weight. Additionally, the lack of continental plate tectonics on Mars means there's no lateral movement to limit the height of mountains as there is on Earth.

Question 20

The tallest mountain on a terrestrial world is:
A) Mt. Everest on Earth
B) Mt. Maxwell on Venus
C) the ring of mountains surrounding Copernicus crater on the Moon
D) the ice mountains on Titan
E) Olympus Mons (Mt. Olympus) on Mars

Accepted Answer

The tallest mountain on a terrestrial world is Olympus Mons (Mt. Olympus) on Mars. It measures 21.9 km (13.6 mi) in height, making it almost three times taller than Mt. Everest on Earth.

Quiz 14: Cosmic Samples and the Origin of the Solar System

Which of the following planets does NOT have an atmosphere?

The first technique that allowed astronomers to find exoplanets involved:

A type of planet that our surveys of exoplanets are revealing around other stars, but we don't have any examples of around the Sun are:

One of the best proofs that our theory of how the solar system formed is correct is that astronomers now observe

Which planet in the solar system rotates the most slowly (has the longest "day") ?

Of the following planets which has NO satellites (moons) ?

The telescope in space that allowed astronomers to find thousands of exoplanets and exoplanet candidates by making very careful measurements during a planet transit was called:

Which planet in the solar system has the longest year (orbits the most slowly) ?

At the beginning of the solar system's history, a ready supply of proto-planets or mini-planets crashed into the developing planets and each other - something astronomers call the "era of giant impacts." How long do astronomers estimate this era lasted?

For solid rocky worlds, a general rule is

A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that

The atmosphere of Venus is mostly carbon dioxide, and the atmosphere of the Earth has water vapor. Why are these two gases absent in the atmosphere of the satellite around Saturn called Titan?

Astronomers now believe that the differences in composition among the planets reflect what characteristic in the early solar system

Many worlds in the solar system show extensive impact cratering, dating back billions of years. Which of the following worlds does NOT show such cratering?

One of the best ways to learn more about a world is to have samples from its surface to analyze in our laboratories. From which of the following worlds do we NOT yet have a sample to analyze here on Earth?

Which of these worlds is the most active geologically?

Which of the following is NOT a way that Jovian planets can be distinguished from terrestrial planets?

The reason that Olympus Mons, the tallest mountain on Mars, is taller than Mount Everest (the tallest mountain on Earth) is that:

The tallest mountain on a terrestrial world is: