Earth, Sun, Moon.

3. To spin.
4. A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
7. An imaginary line about which the Earth rotates.
8. A burning ball of gas.
11. The part of the earth's atmosphere which extends from the top of the troposphere to about 30 miles (50 kilometers) above the surface.
13. The laying down of sediment carried by wind, flowing water, the sea or ice.
14. The region of the earth's atmosphere above the stratosphere and below the thermosphere.
16. The planet we live on.
17. An imaginary line drawn around the earth equally distant from both poles, dividing the earth into northern and southern hemispheres and constituting the parallel of latitude 0°.
18. There are eight of these in our Solar System.
21. The lowest region of the atmosphere, extending from the earth's surface to a height of about 3.7–6.2 miles (6–10 km), which is the lower boundary of the stratosphere.
22. An astronomical event where the Moon moves into Earth's shadow, causing it to darken.
24. A celestial body orbiting the earth or another planet.

1. A system of stars, planets, moons, and other objects, bound together by gravitational orbit.
2. The envelope of gases surrounding the earth or another planet.
4. The force that attracts a body toward the center of the earth, or toward any other physical body having mass.
5. The process of wearing or being worn by long exposure to the atmosphere.
6. Holes made by an asteroid or meteor.
9. To orbit.
10. The process of eroding or being eroded by wind, water, or other natural agents.
12. When the Moon blocks out the Sun.
15. The region of the atmosphere above the mesosphere and below the height at which the atmosphere ceases to have the properties of a continuous medium.
19. Earth's only natural satellite.
20. To follow a path.
23. The stellar object that the Earth revolves around