Different colors of light have different wavelengths and energy. (Human eyes detect differences in wavelength and energy as differences in color.) Light toward the red end of the spectrum has longer wavelengths and lower energy than light toward the violet end of the spectrum. Infrared light has even longer wavelengths than red; while ultraviolet has even shorter wavelengths than violet. Wavelength is described in units of length: 10 million nanometers = 1 centimeter.
Credits
Illustration
NASA, ESA, Leah Hustak (STScI)
