Chapter 21 Vocab

Question 1

Terrestrial planet

Answer 1

One of the highly dense planets nearest to the sun; Mercury, Venus, Mars, and Earth

Question 2

Prograde rotation

Answer 2

The counterclockwise spin of a planet or moon as seen from above the planets North Pole; rotation in the same direction as the Suns rotation

Question 3

Retrograde rotation

Answer 3

The clockwise spin of a planet or moon as seen from above the planets North Pole

Question 4

Gas giant

Answer 4

A planet that has a deep, massive atmosphere, such as Jupiter, Saturn, Uranus, and Neptune

Question 5

Satellite

Answer 5

A natural or artificial body that revolves around a planet

Question 6

Phase

Answer 6

The change in the sunlit area of one celestial body as seen from another celestial body

Question 7

Eclipse

Answer 7

An event in which the shadow of one celestial body falls on another

Question 8

Comet

Answer 8

A small body of ice, rock, and cosmic dust that follows an elliptical orbit around the sun that gives off gas and dust in the form of a tail as it passes close to the sun

Question 9

Asteroid

Answer 9

A small, rocky, object that orbits the sun, usually in a band between the orbits of Mars and Jupiter

Question 10

Asteroid belt

Answer 10

The region of the solar system that is between the orbits of Mars and Jupiter and in which most asteroids orbit

Question 11

Meter oil

Answer 11

A relatively small, rocky body that travels through space

Question 12

Meteorite

Answer 12

A meteoroid that reaches the earths surface without burning up completely

Question 13

Meteor

Answer 13

A bright steak of light that results when a meteoroid burns up in the earths atmosphere

Question 14

Astronomical unit

Answer 14

The average distance between the Earth and the sun; approximately 150 million kilometers