Across
1
Positive particle in nucleus
4
The Red Planet
6
Naturally occurring inorganic solid
7
Unit of energy
8
Icy body with a tail near the sun
10
Blocking of light by a celestial body
11
Absolute temperature scale unit
Down
2
Center of an atom or cell
3
Nerve cell in the brain
4
Molten rock beneath Earth surface
5
Mass per unit volume
9
Disturbance that transfers energy
12
Particle of light