| A | B |
|---|
| atmosphere | layer of gases around some planets, moons, and stars |
| axis | imaginary line that goes straight through the center of the earth |
| gravity | pull between the center of two objects |
| lunar phases | what we see of the moon's lighted half |
| meteorite | space rock that crashes into a planet or moon |
| orbit | path an object takes through space |
| revolve | means "to orbit" and causes the seasons |
| rotate | means "to spin" and causes day and night |
| satellite | object that orbits a planet |
| solar system | the sun, planets, and moons |
| sphere | round body, globe, ball |
| observatory | place with telescopes for studying space |
| horizon | line where earth seem to touch the sky |
| star | ball of burning gas that gives off light |
| sunspots | dark spots that are cooler |
| time of one revolution | 365 days |
| time of one rotation | 24 hours |
| planet | the largest objects that orbit the sun |
| universe | all the galaxies and the space between |
| new moon | the moon is dark |
