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CH21- L1-4
CH21- L1-3
Term | Definition |
---|---|
asteroid | millions if small rocky objects |
comet | gas dust and ice that moves around the sun in an oval-shaped orbit |
astronomical unit | the average distance between the earth and sun |
period of revolution | the time a planet takes to orbit around the sun |
period of rotation | the time it takes a planet to complete one rotation |
terrestrial planet | the planets that are closest to the sun |
greenhouse effect | the atmosphere traps solar energy. |
Galilean moons | made of rock and ice. other planets moons |
meteoroid | A small rocky particle floating through space |
meteor | is meteoroid that is in earth's atmosphere |
meteorite | that strikes something |
impact crator | a round depression |