Across
1
Icy body with a tail near the sun
3
Blocking of light by a celestial body
4
Preserved remains of ancient life
6
Form of thermal energy
8
Nerve cell in the brain
11
Measure of matter in an object
Down
2
The Red Planet
3
Our home planet
5
Unit of energy
7
Infectious microscopic agent
9
Substance with pH above 7
10
Unit of power