Across
- 6. a graph plotting star luminosity and temperature
- 8. huge group of stars, dust, gas, planets, and other objects bound together by gravity
- 9. galaxy shaped like a round or flattened ball
- 11. the distance that light travels in one year, about 9.46 trillion kilometers
- 12. the tendency of sound from a moving object to change frequency to a stationary observer
- 13. the amount of energy a star gives off from its surface
Down
- 1. galaxy that does not have a regular shape
- 2. a phenomenon in which the wavelengths of light from a source shifts to the red end of the spectrum
- 3. a theory that proposes that the universe formed in an instant in an enormous explosion
- 4. a well-tested explanation of an aspect of the natural world
- 5. galaxy that appears to have a bulge in the center and arms that spiral outward in a pinwheel pattern
- 7. all of space and everything in it
- 10. a giant ball of hot gas, made mostly of hydrogen and helium