The ninth ray is one of the rays of sunlight. It is considered to be the most mysterious form of light.
Use in canonEdit
In the books it is mainly used in the Atmosphere Factory to create the artificial atmosphere that makes life on Barsoom possible. The ray is collected on the factory's roof, after which it is converted into energy and stored in one of several enormous reservoirs, at which point an electrical current is introduced that presumably converts the energy into a gas. This gas centers of the planet where, as it is released, contact with the ether of space transforms it into atmosphere.
Use in other mediaEdit
In the Disney movie the ninth ray is used by the Therns as both a method of teleportation between Earth and Barsoom, and as a weapon. The weapon can create a blue energy that disintegrates anything it comes in contact with. Dejah Thoris comes close to discovering the ray herself. She hopes to use it as an energy source.