The Universe CH.18

2. First-magnitude stars are __ than fifth-magnitude stars.
5. The most catastrophic of stellar explosions is called a __.
6. The __ cycle is 11 years long.
7. The apparent change of the position of a star due to Earth's orbiting the Sun is called?
9. are sudden, bright, explosive events originating from the Sun's surface
11. The extension of the Earth's equator onto the celestial sphere is called the?
13. Stars are born in giant clouds of gas and dust, such as the Great __ in Orion.
14. Type M stars are __ in color.
15. Analysis of the __ of a star reveals the composition of the star.
16. A red giant star ends its life as a __ Dwarf.
17. When a star runs out of nuclear fuel, the core begins to __.
19. is the totality of matter, energy, and space.
20. The Sun's energy comes from the __ of hydrogen into helium.

1. A "new" star is called a __.
3. The longitude of a place on the Earth's surface is comparableto the ___ of the star on the celestial sphere.
4. The celestial sphere is divided into 88 __.
8. The apparent annual path of the Sun on the celestial sphere is called the ___.
10. The diagonal group of stars on an H-R diagram is called the __.
12. Astronomers think a __ black hole lies at the center of the Milky Way.
18. Pulsars are a type of __ star.