Across
1
Precious yellow metallic element
3
Force that attracts objects together
4
Blocking of light by a celestial body
7
Ball of burning gas in space
9
Curved glass that refracts light
12
Particle of light
Down
2
Reddish electrical conductor
5
Unit of power
6
Group of similar cells
8
Push or pull on an object
10
Unit of electric potential
11
Hottest planet in solar system