Astronomy Chapter Nine

1. Which of the following is furthest from the Sun?

Pluto

Neptune

An asteroid in the asteroid belt

A comet in the Kuiper belt

A comet in the Oort cloud

2. What is a meteorite?

A streak of light caused by a star moving across the sky

A streak of light caused by a small particle from space burning up in Earth's atmosphere

A fragment of an asteroid from the solar system that has fallen to Earth's surface

A small moon that orbits one of the giant planets

A comet that burns up in Earth's atmosphere

3. How do asteroids differ from comets?

Asteroids are made of rocky material. Comets are made of icy material.

Asteroids are made of icy material. Comets are made of rocky material.

Asteroids and comets are both made of rocky and icy material, but asteroids are larger in size than comets.

Asteroids and comets are both made of rocky and icy material, but asteroids are smaller in size than comets.

4. Why do asteroids and comets differ in composition?

Asteroids formed inside the frost line, while comets formed outside.

Asteroids and comets formed at different times.

Comets formed from the jovian nebula, while asteroids did not.

Comets are much larger than asteroids.

Asteroids are much larger than comets.

5. What is Charon?

Pluto's largest moon

The largest known asteroid

The largest known comet

One of the Galilean moons of Jupiter

A moon of Neptune

6. Why won't Pluto collide with Neptune?

Pluto's orbit is completely outside Neptune's orbit.

Pluto's orbit is completely inside Neptune's orbit.

Pluto's orbit never comes anywhere close to Neptune's orbit.

The two planets have an orbital resonance that prevents them from colliding.

It could!

7. Why aren't small asteroids spherical in shape?

The strength of gravity on small asteroids is less than the strength of the rock.

Small asteroids have odd shapes because they were all chipped off larger objects.

Large asteroids were once molten and therefore became spherical, but small asteroids were never molten.

8. Rather than being a planet, Pluto is really just a large member of

The asteroid belt.

The Kuiper belt.

The Oort cloud.

The moon system around Neptune.

An extrasolar planetary system.

9. What is the name of the largest known Kuiper Belt Object?

Pluto

Charon

Sedna

Quaoar

Xena

10. A rocky leftover planetesimal orbiting the Sun is

A comet.

A meteor.

An asteroid.

A meteorite.

Possibly any of the above

11. When was Pluto discovered?

About 25 years ago

About 75 years ago

About 200 years ago

About 2000 years ago

In ancient history

12. Processed meteorites with high metal content probably are

Leftover chunks of rock from the earliest period in the formation of the solar system.

Pieces of comets rather than of asteroids.

Chunks of a larger asteroid that was shattered by a collision.

Chunks of rock chipped off the planet Mercury.

Chunks of rock chipped off the planet Mars.

13. Comets with extremely elliptical orbits, like comets Hyakutake and Hale-Bopp,

Come from the asteroid belt.

Come from the Kuiper belt.

Come from the Oort cloud.

Are Trojan comets.

Are captured by Jupiter.

14. According to the nebular theory, how did the Kuiper belt form?

It is made of planetesimals that formed beyond Neptune's orbit and never accreted to form a planet.

It is made of planetesimals between the orbits of Mars and Jupiter that never formed into a planet.

15. Which of the following statements about comets and asteroids is true?

Only asteroids collide with Earth.

Comets are balls of ice and dust.

Most of the trillions of comets in our solar system have tails.

All asteroids lie in the asteroid belt between Mars and Jupiter.

There are about 1 million known asteroids in the solar system.

16. Why does the plasma tail of a comet always point away from the Sun?

The solar wind blows the ions directly away from the Sun.

Radiation pressure from the Sun's light pushes the ions away.

The conservation of the angular momentum of the tail keeps it always pointing away from the Sun.

Gases from the comet, heated by the Sun, push the tail away from the Sun.

It is allergic to sunlight.

17. Why was the Shoemaker-Levy 9 impact so important to astronomers?

It dredged up material that gave us our first direct look at Jupiter's interior composition.

It wiped out the dinosaurs.

It was the first direct proof that impacts really occur.

It confirmed our theory of solar system formation.

It was the first event in modern history that was brighter than the full moon in the sky.

18. On average, how often do impactors about 10 km in size, large enough to produce mass extinction, hit Earth?

Once every century

Once every thousand years

Once every million years

Once every hundred million years

Once in Earth's history

19. Which is closest to the average distance between asteroids in the asteroid belt?

1 hundred km

1 thousand km

10 thousand km

1 million km

10 million km

20. According to the nebular theory, how did the Oort cloud form?