Spectrograph has revolutionized astronomy. Ordinary light reaching the earth from the sun, stars, reflection from the surfaces of the moon and the planets, brings quite a bit of information about the heavenly bodies. Another example of a wave is sound, the subject area called Acoustics. Sound requires a medium to travel unlike light waves which can penetrate through the vast empty space. Light is made up of electric fields and magnetic fields, hence called Electromagnetic waves.
Light is only one type of electromagnetic waves.
Speed of light is tremendous. Here, h is called Planck's constant. Energy relation shows that as wavelength becomes shorter, the energy becomes larger. We are familiar with microwave ovens used to cook our food. Our eyes do not see it as a color.