The Universe

2. Dense remnant of star that can only be seen as an absence of light.
5. When a star runs out of energy and collapses, the rebounding material forms a massive explosion called.
6. Force that pulls matter closer together.
11. The apparent movement of stars when observed at different times of the year.
15. The model of the solar system with the Sun at its center.
16. Process by which Hydrogen becomes Helium.
17. Commonly used to measure distances in space. (5,4)
18. Type of star with an absolute magnitude +10 to +16 and temperature >4400 degrees celcius. (5,5)
19. A theory of how the universe started.

1. Rapidly spinning neutron star.
3. Common issue of refracting telescopes, solved by using reflection.(9,10))
4. The lens at the end of a refracting telescope that collects and focuses light to form an image.
7. A giant cloud of gas and dust in space where stars form.
8. A type of electromagentic wave that is emitted by our Sun.
9. The lens that magnifies an image. (3,5)
10. The model of the solar system with the Earth at its center.
12. Evidence that galaxies are moving away from our own.
13. Another word for moon.
14. Another word for brightness.