Across
1
Blocking of light by a celestial body
6
Second lightest element
7
Measure of matter in an object
8
Absolute temperature scale unit
10
Amplified beam of light
13
Group of similar cells
Down
2
Path of a planet around the sun
3
Chemical element in table salt
4
Curved glass that refracts light
5
Tectonic landmass section
9
Tissue that contracts for movement
11
Gas essential for breathing
12
Disturbance that transfers energy