Across
1
Blocking of light by a celestial body
5
Natural satellite of Earth
6
Precious yellow metallic element
9
Icy body with a tail near the sun
11
Substance with pH above 7
12
Mass per unit volume
13
Curved glass that refracts light
Down
2
Glass that splits light into spectrum
3
Tissue that contracts for movement
4
Solid with repeating atomic pattern
7
Biological catalyst
8
Compound containing oxygen
10
Gas essential for breathing
14
Ball of burning gas in space