1.   Herschel had found the infra-red detected invisible light in the form of radiant heat.

2.   Soon, I thought, I would be swapping files over pulses of invisible light.

3.   The instrument bathes the sample in invisible infrared light, and then looks at the resulting unique molecular signature.

4.   Those beams of invisible light can be bounced off ceilings, walls, furniture and even people.

5.   When the electrons decay, in a process called fluorescence, they emit invisible light close to the ultraviolet and infrared parts of the electromagnetic spectrum.

6.   It carries four instruments that can detect natural gamma rays, a powerful form of invisible light that bathes the universe.