The Study of the Universe

Across
2.	The study of space and everything beyond earth.
6.	A constellation known as the queen.
8.	Rising and falling of the sea.
9.	A medium sized yellow dwarf star in our solar system.
10.	A natural satellite of the Earth.
11.	A chunk of ice, dust or rock that orbits the sun.
12.	Gasses and charged particles are expelled above a sunspot.
14.	A theory of the creation of the universe.
15.	A large celestial object that circles a star.
17.	Obscuring of light from one celestial body passing in front of another.
18.	The layer of gasses surrounding the Earth.
19.	A celestial object that orbits a planet.

Down
1.	A group of stars held together by gravity.
3.	The path an object follows as it circles another.
4.	A large number of meteors falling in the sky and burning up.
5.	The planet on which we live.
7.	A dark spot on the sun's surface.
13.	The distance a light ray travels in 1 year.
16.	Also known as the North Star.