Across
1
Nerve cell in the brain
4
Icy body with a tail near the sun
6
Our home planet
7
Unit of electric potential
8
Amplified beam of light
10
Glass that splits light into spectrum
11
Curved glass that refracts light
Down
2
Blocking of light by a celestial body
3
Absolute temperature scale unit
4
Reddish electrical conductor
5
Compound containing oxygen
9
Precious yellow metallic element
12
The Red Planet