front 1 asteroid | back 1 a small rocky body orbiting the sun |
front 2 asteroid belt | back 2 the region of the solar system between the orbit of mars and jupiter |
front 3 atmosphere | back 3 the mixture of gases that surrounds a planet or moon |
front 4 comet | back 4 a small body of matter from outer space . |
front 5 crater | back 5 a large round pit caused by the impact of a meteoroid |
front 6 galaxy | back 6 a collection of stars , dust and gas bound together by gravity |
front 7 gas giant | back 7 the outer planets |
front 8 gravity | back 8 a force that pulls objects toward each other |
front 9 planets | back 9 a celestial body moving in a elliptical orbit around a star |
front 10 moon | back 10 a natural object that orbits a planet |
front 11 milky way | back 11 the galaxy containing the solar system |
front 12 orbit | back 12 the path an object follows as it moves around another object . |
front 13 revoulution | back 13 the movement of an object around another object . |
front 14 rotation | back 14 the spinning motion of a planet on its axis . |
front 15 solar system | back 15 the collection of eight plants and their moons in orbit around the sun |
front 16 star | back 16 a ball of hot gas , primarily hydrogen and helium , that undergoes nuclear . |
front 17 terristial | back 17 the name of the inner planets . |
front 18 dwarf planets | back 18 a celestial body resembling a small planet but lacking certain technical criteria that are required for it to be classified as such . |
front 19 light year | back 19 the distance light travels in one year . |
front 20 kuiper belt | back 20 a region of the solar system that is just beyond the orbit of neptune . |
front 21 meteor | back 21 a small body of matter from outer space that enters the earth's atmosphere appearing as a streak of light . |
front 22 universe | back 22 all of space and everything in it . |