ch.11

Question 1

What are the two types of small bodies orbiting the Sun?

Answer 1

Asteroids and comets

Question 2

What are asteroids primarily composed of?

Answer 2

Rocky objects

Question 3

What are comets primarily composed of?

Answer 3

Icy bodies

Question 4

What do asteroids and comets represent in the Solar System?

Answer 4

Remnants of the formation of the Solar System

Question 5

What are planetesimals?

Answer 5

Small bodies that may be remnants of the Solar System’s formation

Question 6

What role do asteroids and comets play in planetary impact?

Answer 6

They can have a large influence on Earth’s biological life

Question 7

What is a meteor?

Answer 7

A streak of light from a solid object heated by friction in the Earth’s atmosphere

Question 8

What is the solid body in space called before it enters the atmosphere?

Answer 8

Meteoroid

Question 9

What are meteorites?

Answer 9

Solid bodies that reach the Earth’s surface

Question 10

What are the three broad categories of meteorites?

Answer 10

• Iron
• Stony
• Stony-iron

Question 11

What are carbonaceous chondrites?

Answer 11

Stony meteorites with organic carbon-rich compounds

Question 12

Where do most asteroids lie in the Solar System?

Answer 12

In the asteroid belt between Mars and Jupiter

Question 13

What is the combined mass of all asteroids compared to Earth?

Answer 13

Less than 1/1000 the mass of the Earth

Question 14

What are Near-Earth Objects (NEOs)?

Answer 14

Objects whose orbits carry them into the inner Solar System and across Earth’s orbit

Question 15

Who discovered Pluto and when?

Answer 15

Clyde Tombaugh in 1930

Question 16

What is the name of Pluto’s moon?

Answer 16

Charon

Question 17

When was Pluto classified as a Dwarf Planet?

Answer 17

In 2006

Question 18

What are the main components of a comet’s structure?

Answer 18

• Tail
• Coma
• Nucleus

Question 19

What is the tail of a comet?

Answer 19

A narrow column of gas and dust that points away from the Sun

Question 20

Where do most comets originate?

Answer 20

The Oort Cloud

Question 21

What is the Kuiper belt?

Answer 21

A region beyond Neptune’s orbit containing icy bodies

Question 22

What defines short-period comets?

Answer 22

Comets with periods of less than 200 years

Question 23

What causes meteor showers?

Answer 23

Earth passing through a comet’s dust-filled orbit

Question 24

What is the radiant in a meteor shower?

Answer 24

The point in the sky from which meteors seem to emerge

Question 25

What is the Tunguska event?

Answer 25

An asteroid broke up in the atmosphere in Siberia in 1908

Question 26

What evidence links an impact to the extinction of dinosaurs?

Answer 26

High abundance of iridium in sediments

Question 27

What is the average density of an asteroid?

Answer 27

About 2 g/cm³

Question 28

What is the composition of asteroids mainly classified as?

Answer 28

Carbonaceous, silicates, and metallic iron-nickel

Question 29

What planet creates gaps in the asteroid belt?

Answer 29

Jupiter

Question 30

What are the gaps created by Jupiter called?

Answer 30

Kirkwood gaps

Question 31

What are comets rich in?

Answer 31

* Water * Carbon monoxide (CO) * Carbon dioxide (CO2)

Question 32

What distinguishes short-period comets from long-period comets?

Answer 32

Short-period comets are from the Kuiper belt; long-period comets are from the Oort cloud

Question 33

Meteor showers are generally named after what?

Answer 33

The constellation from which they appear to diverge

Question 34

What is the evidence for the existence of the Kuiper belt?

Answer 34

The existence of short-period comets

Question 35

What supports the existence of the Oort cloud?

Answer 35

The fact that new comets continue to appear

Question 36

What is a characteristic of the Leonid meteor shower?

Answer 36

The radiant is in the constellation of Leo

Question 37

How often does Halley's comet orbit the Sun?

Answer 37

Approximately every 76 years

Question 38

What is a key feature of chondritic meteorites?

Answer 38

They contain grains from the first material that condensed out of the solar nebula

Question 39

What travels the farthest from the Sun?

Answer 39

Comets

Question 40

Chondritic meteorites provide important clues because they are believed to _______.

Answer 40

Contain grains from the first material that condensed out of the solar nebula ## Footnote Chondritic meteorites are often studied to understand the early solar system.

Question 41

_____ travel(s) the farthest from the Sun.

Answer 41

Comets ## Footnote Comets have highly elliptical orbits that can take them far from the Sun.

Question 42

The Trojan asteroids orbit the Sun at an average distance of ____.

Answer 42

60° ahead and 60° behind ## Footnote Trojan asteroids share an orbit with a larger planet, typically located at stable points known as Lagrange points.

Question 43

The tail of a comet always points _____.

Answer 43

Away from the Sun ## Footnote The tail of a comet is formed by solar wind and radiation pressure pushing gas and dust away.

Question 44

The typical size of a comet's nucleus is _____.

Answer 44

10 km ## Footnote Comet nuclei can vary in size, but many are around 10 km in diameter.

Question 45

The coma around the nucleus of a comet can be 10 times the size of the Earth. True or False?

Answer 45

True ## Footnote The coma can expand significantly when a comet approaches the Sun.

Question 46

The combined mass of thousands of asteroids is less than 1/1000 the mass of the Earth. True or False?

Answer 46

True ## Footnote This demonstrates the relatively small size of the asteroid belt compared to Earth.

Question 47

The existence of amino acids in carbonaceous chondrites proves that life on Earth originated in space. True or False?

Answer 47

False ## Footnote While amino acids have been found in meteorites, this does not definitively prove extraterrestrial origins of life.

Question 48

Astronomers believe that most of the meteorites come from broken up asteroids and comets, but some of the meteorites are fragments from the Moon or Mars. True or False?

Answer 48

True ## Footnote Meteorites can originate from various celestial bodies, including the Moon and Mars.

Question 49

Some asteroids have peculiar orbits that do not obey Kepler's laws. True or False?

Answer 49

True ## Footnote These asteroids may be influenced by gravitational interactions or other forces.

Question 50

In the inner part of the asteroid belt one is more likely to find silicate-rich asteroids, while the carbon-rich asteroids are more abundant in the outer parts of the asteroid belt. True or False?

Answer 50

True ## Footnote This distribution is a result of the formation conditions in the early solar system.

Question 51

Comets consist primarily of water, carbon dioxide and carbon monoxide. True or False?

Answer 51

True ## Footnote Comets are often described as 'dirty snowballs' due to their icy composition.

Question 52

Halley's comet orbits the Sun approximately every 76 years, therefore it is a long-period comet. True or False?

Answer 52

False ## Footnote Halley's Comet is classified as a short-period comet due to its relatively brief orbital period.

Question 53

The Oort cloud was probably formed by planetesimals that were tossed to the outer parts of the solar system by the planets. True or False?

Answer 53

True ## Footnote The Oort cloud is a theoretical cloud of icy bodies believed to be the source of long-period comets.