Lesson 17 Crossword

3. - a small rocky body orbiting the sun
5. - a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction
7. - the action or process of re-entering something
10. - the 3rd planet from the Sun; the planet we live on
12. - the 9th planet from the Sun; also known as the dwarf planet
13. - a group of visible stars formed to perceive an outline or pattern
14. - the 7th planet from the Sun
15. - a celestial body that obscures the light from or to another celestial body
16. - an act of counting numerals in reverse order to zero
17. - an artificial body placed in orbit around the earth or moon or another planet in order to collect information or for communication
18. - the 4th planet from the Sun; the “red planet”
20. - the 5th planet from the Sun
21. - the envelope of gases surrounding the earth or another planet
23. - the circular movement of an object around an axis of rotation
24. - the 2nd planet from the Sun

1. - the smallest and closest planet to the Sun
2. - a pair of robotic probes launched to observe and to transmit information to Earth about the giant planets of the outer solar system
4. - the 6th planet from the sun
6. - an instance of revolving
8. - the state of apparently not being acted on by gravity; the state of being weightless
9. - the 8th planet from the Sun
11. Way - the galaxy that includes our Solar System
12. - a substance that propels something
19. - a person who is trained to travel in a spacecraft
22. - an expert in or student of astronomy