Across
1
Blocking of light by a celestial body
6
Compound containing oxygen
7
Nerve cell in the brain
8
Element found in all living things
11
Glass that splits light into spectrum
12
Amplified beam of light
Down
2
Particle of light
3
Unit of energy
4
Center of an atom or cell
5
Icy body with a tail near the sun
9
Unit of power
10
Absolute temperature scale unit