All bodies are composed of elementary particles (protons, neutrons, electrons). The same is observed in the nature of electromagnetic radiation. Only the electromagnetic field consists of special particles - photons. They do not have their own weight and are small blobs of energy, which is perpendicular relative to each other fluctuating electric and magnetic forces.
The photon is constantly moving as fast as possible and at the same time ranges. In a vacuum (in a vacuum) all photons travel at the same speed (300 000 kilometers per second - the speed of light. In one second light from the Earth reaches almost to the moon. In other matters - glass, water, air, etc. - light and other electromagnetic radiation move slower.
Photons fill the whole Universe and all of her body. In space there are photons of different types of energies. They bring solar energy to the Earth, carry information about the body in which they were born, and the space through which penetrated. We know the world around us by using photons of light.