Across
1
Fourth state of matter
4
Reddish electrical conductor
6
Icy body with a tail near the sun
7
Tectonic landmass section
10
Magnetic metallic element
Down
2
Absolute temperature scale unit
3
Natural satellite of Earth
5
Blocking of light by a celestial body
8
Smallest unit of an element
9
Mass per unit volume
11
Curved glass that refracts light
12
The Red Planet