Across
1
Substance with pH below 7
3
Hottest planet in solar system
5
Blocking of light by a celestial body
7
Solid with repeating atomic pattern
8
Curved glass that refracts light
Down
2
Icy body with a tail near the sun
4
Center of an atom or cell
6
Nerve cell in the brain
9
Tissue that contracts for movement
10
Fourth state of matter