Light travels in waves of frequency and as particles of matter. There are many types of light, of which the visible spectrum is a small part.
Visible light is the light that can be seen with the naked eye. It is one type of electromagnetic radiation, which results from the vibrations of electric and magnetic fields. Other types of light that exist in the electromagnetic spectrum include
- Gamma rays
- Ultraviolet rays
Television, radio and microwaves also exist on the EM spectrum. These waves have some of the lowest energy levels on the spectrum while gamma rays have some of the highest. The wavelengths of these rays are not captured by the human eye and are thus considered invisible. The visual range of the EM spectrum appear in different colors.
Another way that light is said to travel is as particles, or packets of energy. These packets are called photons, which are elementary particles that carry EM force. The concept of photons was developed by Albert Einstein to describe the actions of light that did not follow the convention of waves.
Light moves very rapidly, but does have a maximum velocity of 186,282 miles per second. In astronomy, a light year equals 5.8 trillion miles, which is the distance light can travel at its maximum speed for the span of a year.