Mastering Astronomy Chapter 7

What are some of the things that make Earth unique in the solar system?

-Its surface temperature is such that water can exist in three phases: solid, liquid, and gaseous. -It is the only planer that is known to harbor life.

Based on the frequency with which we see comets from Earth, astronomers estimate the total number of comets in the solar system to be

1 trillion

Which of the following best describes Pluto in terms of the general characteristics of terrestrial and jovian planets?

size and solid surface similar to terrestrial planets; distance similar to jovian planets

Astronomers have decided that, rather than being a planet, Pluto is really just a large member of

the Kuiper belt

Rank Mercury, Saturn, Earth, Pluto, Jupiter, and Mars based on their average distance from the Sun, from farthest to closest.

Pluto, Saturn, Jupiter, Mars, Earth, Mercury

The planet with the lowest average density is ________.

Saturn

Which of the following is not an advantage of spacecraft flybys over ground-based telescope observations?

Spacecraft can monitor changes in a planet's atmosphere over long times.

Rank the Sun, Jupiter, Earth, Mars, Mercury and Pluto from largest to smallest.

Sun, Jupiter, Earth, Mars, Mercury, Pluto

Rank the Sun, Jupiter, Earth, Pluto, Mercury, and Mars based on their mass, highest to lowest.

Sun, Jupiter, Earth, Mars, Mercury, Pluto

Which of the following is not a pattern of motion in our solar system?

Planets all rotate in the same direction

Which of the following is farthest from the Sun?

A comet in the Oort cloud

What is the Kuiper belt?

A region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets.

Which jovian planet does NOT have rings?

All the jovian planets have rings.

Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?

All the planets orbit counterclockwise around the Sun.

How do asteroids differ from comets?

Asteroids are rocky bodies and are denser than the comets, which are made of icy material.

_________ is about 30 times as far from the Sun as our own planet.

Neptune

Where are most of the known asteroids found?

Between the orbits of Mars and Jupiter

Which is the densest planet in the solar system?

Earth

Most of the surface of _________ is covered with liquid water.

Earth

All comets orbit the Sun in the same direction as the planets.

False

All the planets in the solar system have at least one moon.

False

The planet Uranus held a special place in the mythology of the ancient Romans.

False

Robotic spacecraft have different levels of complexity, which contributes to overall cost. Which of the following types of missions are likely to be the cheapest?

Flybys

What are the main constituents of the jovian planets?

Hydrogen and helium

Where does nuclear fusion occur in the Sun?

In its core

Which of the following statements about Pluto is true?

It has more in common with comets in the Kuiper belt than it does with terrestrial planets like Earth.

How does the Sun's mass compare with that of the planets?

It is a thousand times more massive than all the planets combined.

Rank Neptune, Earth, Jupiter, Mercury, and Mars based on the amount of time it takes them to orbit the Sun from longest to shortest.

Neptune, Jupiter, Mars, Earth, Mercury

What is the Oort cloud?

It's not really a cloud at all, but rather refers to the trillion or so comets thought to orbit the Sun at great distances.

Pluto is different from the outer planets in all of the following ways except which one?

Its surface temperature is very cold.

________ is the jovian planet that orbits closest to the Sun.

Jupiter

Rank Earth, Mars, Jupiter and Mercury based on the amount of moons they have, highest to lowest.

Jupiter, Mars, Earth, Mercury

Estimate the distance between Venus and Earth in km and AU.

Km- 4.2*10^7 AU- .28

The only rocky planet to have more than one moon is_______.

Mars

Which planet, other than Earth, has visible water ice on it?

Mars

The most metal-rich terrestrial planet is

Mercury

The planet that orbits closest to the Sun is _______.

Mercury

Rank Neptune, Jupiter, Mars, Earth and Mercury based on average surface temperature, from highest to lowest.

Mercury, Earth, Mars, Jupiter, Neptune

Which of the following statements is not an observed pattern of motion in our solar system?

Most planets orbit at the same speed.

What is the primary reason why a Pluto flyby mission would be cheaper than a Pluto orbiter?

The fuel needed for an orbiter to slow down when it reaches Pluto adds a lot of weight to the spacecraft.

Which of the following is not an exception to the general patterns in the solar system?

The rings of Saturn

What is aerobraking?

The technique of using a planetary atmosphere to change the orbit of a spacecraft

Which of the following observations indicates that conditions on Mars may have been suitable for life in the past?

There is liquid water as well as a significant number of dried-up riverbeds on Mars.

Which of the following is not a characteristic of the inner planets?

They all have substantial atmospheres

Which of the following is not a characteristic of the outer planets?

They have very few, if any, satellites.

All four of the giant outer planets- Jupiter, Saturn, Uranus, and Neptune- have rings.

True

All planets orbit the Sun in the same direction (counterclockwise as viewed from above Earth's North Pole).

True

Oceans cover more of Earth's surface than land

True

The jovian planets have no solid surface

True

The more massive planets in the solar system tend to be less dense than the lower mass planets.

True

__________ has a rotational axis that is tilted so much it lies nearly in the plane of its orbit.

Uranus

Which planet has a ring system?

Uranus, Saturn, Jupiter, and Neptune

The planet closest in size to Earth is

Venus

__________ is the planet with the highest average surface temperature.

Venus

Which planet has the highest average surface temperature, and why?

Venus, because of its dense carbon dioxide atmosphere

How many Earths could fit inside Jupiter? The equation for the volume of a sphere is V=(4/3)πr^3. (The radius of Jupiter is RJupiter=71492 km.)

approx. 1410

How many Jupiters could fit inside the Sun? The equation for the volume of a sphere is V=(4/3)πr^3.

approx. 919