Across
1
Absolute temperature scale unit
3
Blocking of light by a celestial body
4
Mass per unit volume
5
Reddish electrical conductor
6
Solid with repeating atomic pattern
10
The Red Planet
11
Ball of burning gas in space
12
Our home planet
Down
2
Substance with pH above 7
3
Biological catalyst
5
Icy body with a tail near the sun
7
Second lightest element
8
Unit of energy
9
Gas essential for breathing