Across
1
Blocking of light by a celestial body
4
Path of a planet around the sun
8
Solid with repeating atomic pattern
10
Nerve cell in the brain
11
Force that attracts objects together
Down
2
Glass that splits light into spectrum
3
Mass per unit volume
5
Biological catalyst
6
Smallest unit of an element
7
The Red Planet
9
Chemical element in table salt
12
Hottest planet in solar system