We are all familiar with the colours of the rainbow, but light has many more colours –only our eyes cannot see them. Then, how do we know about them? 

Physicists describe light as something called an electromagnetic wave. Our eyes are adapted to detect only a small portion of this spectrum, and this portion is what we call “visible light”. Different wavelengths of visible light are perceived by our eyes as different colours. Gamma rays have the shortest wavelength, and radio waves the longest. Thus, the only difference between the colours of visible and invisible light is their wavelength (or frequency) 

ESASky is a science-driven discovery portal providing access to the full sky as observed by space astronomy missions from ESA and other  agencies, very visual and easy to use, and that requires no previous knowledge of the mission or data.