Astronomy Vocabulary

Across
5.	planets similar to Jupiter, large gas and low density
7.	model of the solar system with the Earth at the center
8.	the shortest type of electromagnetic radiation
12.	the galaxy that we live in
14.	young average stars like the sun
15.	a change in wavelength caused by movement
17.	everything known to exist
18.	a spherical object that orbits a star
19.	when a star moves towards us and its wavelengths are closer together
20.	hydrogen molecules combine to make helium and release energy

Down
1.	the brightness of a star compared to the sun
2.	the cloud of gas and dust that stars form in
3.	a collection of gravitationally bound stars
4.	planets similar to earth, small rocky and dense
6.	the idea that the universe began as a single point 13.7 billion years ago
9.	this object orbits the Earth in both the geocentric and heliocentric model of the solar system
10.	the star closest to the earth
11.	when a star moves away from us and its wavelengths are further apart
13.	gas and dust combining together into larger and larger pieces
16.	model of the solar system with the Sun at the center