Across
1
Ball of burning gas in space
4
Amplified beam of light
5
Our home planet
7
Second lightest element
8
Positive particle in nucleus
11
Center of an atom or cell
Down
2
Molten rock beneath Earth surface
3
Hottest planet in solar system
6
Path of a planet around the sun
9
Measure of matter in an object
10
Gas form of a liquid
12
Form of thermal energy