Astronomy Unit: Essential Vocab

3. The spiral galaxy which our solar system exists in.
6. ______ are billions of stars held together by their mutual gravity.
7. The moon is ____ hundred thousand miles away from Earth.
9. A celestial body that orbits the sun made of dust gas and ice.
10. Core of a star that remains after a supernova explosion.
12. Actually, the weakest of the fundamental forces, because it is a purely attractive long-range force.
13. ______ consists of planets, moons, stars or other cosmic bodies that orbit a star.
16. A theory that says a universe is constantly expanding which causes the galaxies and matter in the universe to disperse and move away from each other. The idea that matter is just formed out of nothing and grow.
19. A celestial body that makes an orbit around a planet.
20. A highly compacted object where the speed of light is weaker than the escape speed.

1. An astronomical measure for how far away objects in space are.
2. Quasi-stellar radio source. Very energetic and distant active galactic nucleus.
4. The theory that the universe began with a huge explosion that scattered matter and atoms which eventually evolved to stars,galaxies and etc.
5. Where the earth gets most of it's energy.
8. A group of stars that are near one another and named.
11. A massive, luminous sphere of plasma held together by its own gravity.
14. Small, often irregularly shaped rocky bodies that orbit the Sun.
15. When light from an object moves away from the observer increasing in wavelength, shifting to the red end of the light spectrum.
16. The collapse of a neutron star or runaway thermonuclear reaction.
17. The closest big galaxy from Earth.
18. The most distant object we have seen so far is __ billion light years away.