| A | B |
|---|
| asteroid | Rocky objects revolving around the sun that are too small and numerous to be considered planets. Made from left over solar system material. Located mostly between Jupiter and Mars |
| Asteroid belt | the region of the solar system between the orbits of Mars and Jupiter, where many asteroids are found |
| comet | large clumps of ice, dust and frozen gases that travel around the Sun in long elliptical orbits |
| Galilean Moons | the name given to Jupiter's four largest moons, Io, Europa, Callisto and Ganymede. |
| gas giants | the first four outer planets Jupiter, Saturn, Uranus, and Neptune |
| elliptical orbit | an orbit that is long and flat, oval or egg shaped orbit |
| gravity | force of attraction between all objects in the universe |
| greenhouse effect | the process by which heat is trapped in the atmosphere by water vapor, carbon dioxide, methane, and other gases that form a "blanket" around the earth |
| meteor | any of the small solid extraterrestrial bodies that hits the earth's atmosphere |
| meteorites | small bodies that enter the Earth's atmosphere and land on its surface |
| meteroids | small rocky objects that orbit the sun in both the outer and inner regions of the solar system |
| nuclear fusion | the combination of the nuclei os small atoms to from a larger nucleus: releases energy. This is how the sun gets its energy |
| orbit | the path of an object as it revolves around another object in space |
| osteoporosis | a condition in which the body's bones become weak an break easily |
| terrestrial planets | one of hte dense rocky planets nearest to the sun; Mercury, Venus Earth Mars |
