Across
1
Icy body with a tail near the sun
5
Force that attracts objects together
6
Substance with pH above 7
7
Our home planet
10
Infectious microscopic agent
12
Molten rock beneath Earth surface
Down
2
Blocking of light by a celestial body
3
Path of a planet around the sun
4
Tissue that contracts for movement
8
Second lightest element
9
Unit of power
11
Unit of force