Images All telescopes collect light from objects to make them visible to the eye. However, what we commonly perceive as light is only one type of electromagnetic radiation. Radiation comes in a range of energies, known as the electromagnetic spectrum . The spectrum consists of radiation such as Gamma rays, X-rays, Ultraviolet, Visible, Infrared and Radio. Radiation travels in waves, just like waves in an ocean.
Visible light has a wavelength that is just right for the human eye to detect.
Astronomers use telescopes that can detect different wavelengths in order to see what the universe truly looks like. Our Key to terms has descriptions of some of the telescopes used to produce images of objects at different wavelengths.