Across
1
Push or pull on an object
4
Our home planet
6
Path of a planet around the sun
7
Group of similar cells
10
Molten rock beneath Earth surface
Down
2
Icy body with a tail near the sun
3
Mass per unit volume
5
Second lightest element
8
Tectonic landmass section
9
Blocking of light by a celestial body
11
Ball of burning gas in space