Across
1
Nerve cell in the brain
3
Molten rock beneath Earth surface
4
Blocking of light by a celestial body
9
Solid with repeating atomic pattern
10
Form of thermal energy
11
Glass that splits light into spectrum
12
Path of a planet around the sun
Down
2
Hottest planet in solar system
3
The Red Planet
5
Center of an atom or cell
6
Smallest unit of an element
7
Icy body with a tail near the sun
8
Tissue that contracts for movement