SURFACE
The outermost covering or layer.
EARTH
The planet that all known life exists on.
SUN
The star at the center of our solar system that supplies heat and light to Earth; its enormous gravity keeps the solar system in orbit.
WEIGHT
The heaviness of an object; force of gravity on mass = weight.
CRATERS
Bowl-shaped indents or cavities on the surface of a planet, moon, or asteroid that are caused by a collision with another object, such as a meteorite.
MOON
A natural satellite that orbits a planet; some planets have no moons; others have over 60 moons.
STAR
A flaming ball of gas in space, producing its own heat and light.
PLANET
One of the eight named objects that orbits the Sun.
ATMOSPHERE
A layer of gases surrounding an object in space.
METE0RITE
A relatively small chunk of space rock that strikes the surface of a planet or moon.