Across
1
Gas essential for breathing
3
Disturbance that transfers energy
5
Unit of energy
7
Blocking of light by a celestial body
8
Solid with repeating atomic pattern
12
Precious yellow metallic element
13
Second lightest element
Down
2
Absolute temperature scale unit
4
Icy body with a tail near the sun
6
Mass per unit volume
9
Group of similar cells
10
Our home planet
11
Amplified beam of light