Across
- 3. a person who is trained to travel in spacecraft
- 5. the first planet from the sun
- 8. a star that suddenly increases greatly in brightness as it explodes
- 9. a large celestial body that orbits a star
- 12. the fifth planet from the sun
- 14. a group of stars that form a recognizable pattern
- 17. the branch of science that deals with celestial objects, space, and the physical universe as a whole
Down
- 1. the curved path of a celestial object or spacecraft
- 2. the second planet from the sun
- 4. a vehicle used for traveling in space
- 6. formerly a planet
- 7. a naturally formed body that orbits a planet
- 10. a small rocky body orbiting the sun
- 11. a cloud of gas and dust in outer space
- 13. a system of stars
- 15. the sixth planet from the sun
- 16. National Aeronautics and Space Administration
- 18. the fourth planet from the sun