SEEING INFRARED

Visible to the human eye are the familiar colors of a rainbow. But light sources like the sun also emit invisible radiation at wavelengths slightly longer than red light. Radar, X-rays and infrared radiation are all examples of electromagnetic radiation that we can not see. Part of the infrared spectrum can be captured by special film like that used to produce this image. Scientific research relies on infrared techniques for learning about liquids and solids, and for researching distant stars and galaxies.