Planetary Science Vocabulary

Front

accretion

Back

sticking together (IG)

Front

altitude

Back

the distance above Earth’s surface (IG)

Front

asteroid

Back

a small, rocky object that orbits the Sun (SRB, IG)

Front

asteroid belt

Back

a region between Mars and Jupiter that consists of small chunks of matter that orbit the Sun (SRB)

Front

astronomical unit (AU)

Back

the average distance between Earth and the Sun, about 150 million kilometers (SRB, IG)

Front

atmosphere

Back

a layer of gases that surround an object, held in place by gravity (SRB, IG)

Front

axis

Back

an imaginary axle that a planet spins on (SRB, IG)

Front

big bang theory

Back

a theory that one explosion created the universe (SRB)

Front

binary star

Back

a system of two stars orbiting their barycenter (SRB)

Front

biosphere

Back

a system of interacting living organisms (SRB, IG)