Across
1
Tectonic landmass section
4
Ball of burning gas in space
5
Curved glass that refracts light
6
Gas essential for breathing
9
Chemical element in table salt
12
Absolute temperature scale unit
Down
2
Solid with repeating atomic pattern
3
Unit of electric potential
7
Mass per unit volume
8
Smallest unit of an element
10
Blocking of light by a celestial body
11
Our home planet