Chapter 21 Vocabulary Flashcards
(14 cards)
One of the highly dense planets nearest to the sun; Mercury, Venus, Mars, and Earth
Terrestrial planet
The average distance between the Earth and the sun; approximately 150 million kilometers (Symbol, AU)
Astronomical unit
The counter-clockwise spin of a planet or moon as seen from above the planet’s North Pole; rotation in the same direction as the sun’s rotation
Prograde rotation
A planet that has a deep, massive atmosphere, such as Jupiter, Saturn Uranus, and Neptune
Gas giant
A natural or artificial body that revolves around a planet
Satellite
The change in the sunlit area of one celestial body as seen from another celestial body
Phase
An event in which the shadow of one celestial body falls on another
Eclipse
A small body of ice, rock, and cosmic dust that follows an elliptical orbit around the sun and that gives off gas and dust in the form of a tail a sit passes close to the sun
Comet
A small, rocky object of hat orbits the sun, usually in a band between the orbits of Mars and Jupiter
Asteroid
The region of the solar system that is between the orbits of Mars and Jupiter and in which most asteroids orbit
Asteroid belt
A relatively small, rocky body that travels through space
Meteoroid
A meteoroid that reaches the Earth’s surface without burning up completely
Meteorite
A bright streak of light that results when a meteoroid burns up in the Earth’s atmosphere
Meteor
The clockwise spin of a planet or moon as seen from above the planet’s North Pole
Retrograde rotation
