Across
1
Naturally occurring inorganic solid
6
Hottest planet in solar system
7
Particle of light
8
Icy body with a tail near the sun
Down
2
Unit of heredity
3
Curved glass that refracts light
4
Ball of burning gas in space
5
Smallest unit of an element
7
Glass that splits light into spectrum
9
Path of a planet around the sun