Across
- 2. Composed of particles that do not absorb, reflect, or emit light.
- 3. Star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass.
- 7. All existing matter and space considered as a whole; the cosmos.
- 8. The rapid expansion of matter from a state of extremely high density and temperature that according to current cosmological theories marked the origin of the universe.
- 12. a galaxy in which the stars and gas clouds are concentrated mainly in one or more spiral arms.
- 13. Celestial body distinguished from the fixed stars by having an apparent motion of its own.
Down
- 1. Region of space having a gravitational field so intense that no matter or radiation can escape.
- 4. Cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.
- 5. Unit of astronomical distance equivalent to the distance that light travels in one year.
- 6. The star around which the earth orbits.
- 9. The planet on which we live; the world.
- 10. System of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
- 11. A luminous ball of gas, mostly hydrogen and helium, held together by its own gravity.