Across
- 2. they can be made up of 10 or more clusters of galaxies.
- 5. a large collection of stars, gas, and dust held together by gravity.
- 7. The four planets that orbit nearest to the sun.
- 9. the distance that light travels through space in one year.
- 10. The four planets that orbit farthest from the sun.
- 14. galaxies that look like spheres or ovals and don't have arms.
- 16. they contain as many as thousand galaxies.
Down
- 1. a process that emits energy in the core of the star.
- 3. absorbs harmful solar radiation and other gases that keep Earth warm enough for life to exist.
- 4. huge spherical areas where very little matter exists.
- 6. galaxies that appear as splotchy irregularly shaped blobs.
- 8. space and all the matter and energy in it.
- 11. a large celestial body that is composed of gas and emits light.
- 12. the collection of large and small bodies that orbit our central star, the sun.
- 13. galaxies that are shaped like pinwheels and have a central bulge
- 15. a spherical body that orbits the sun.