5 ATHENA ch17 Scott Foresman 2008

Term Definition
solar system the Sun and all the bodies that orbit it
revolution one full orbit of an object around another object
axis an imaginary center line around which the Earth roatates
rotation one whole spin of an object on its axis
space probe a spacecraft that gathers data without a crew
comet a frozen mass of ice and dust orbiting the Sun
asteroid a rocky mass up to several hundred kilometers wide that revoluves around the Sun
satellite an object in orbit around another object
moon phase an indication of the fraction of the Moon that is illuminated as seen from Earth