UNIT 1: EpitU Vocab

 a collection of stars, dust, and gas bound together by gravity.

all of space and everything in it including stars, planets, galaxies, etc.

 the average distance between the Earth and the Sun (about 150 million kilometres, or 93 million miles).

force of attraction between objects that is due to their masses.

the distance light travels in one year (9.5 trillion kilometers, or 5.9 trillion miles).

a group of planets or celestial bodies that revolve around a star(s).

the movement of one object around another

 a large, round object in space that travels around a star.

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

 a ball-shaped gaseous celestial body (as the sun) of great mass that shines by its own light.