Space 01

3. white ____: the remains once a medium or small star has died
4. force that keeps objects with mass attracted to each other
8. ____ year: common measurement of distance in astronomy
10. man-made orbitter of a planet
11. group of galaxies bound together by gravity
13. celestial body that orbits a planet
15. dark ____: hypothetical force responsible for the universe's accelerating expansion
19. cloud of gas and dust in space
20. orange ____: a medium or small star when it is aging
22. universe's ongoing process of getting bigger
23. celestial body that emits light and heat

1. path a planet takes around its star
2. big ____: theory that explains the origin of the universe
5. HR _____: graph used to classify stars based on temperature and brightness
6. _____ star: the remains once a huge star has died
7. ____ dwarf: a medium or small star that is no longer emitting light
9. black ___: region in space with such strong gravity that nothing can escape it
12. main _____: stage in a star's life when it fuses hydrogen into helium
14. most abundant element in the universe
16. vast collection of stars, gas, and dust
17. celestial body that orbits a star
18. process that powers stars by combining hydrogen atoms
19. super ____: massive explosion in space
21. ____ matter: mysterious substance that makes up most of the universe's mass
23. red ____ giant: a huge star when it is aging