Does Photons exist in free vacuum outer space ?
A photon is simply a packet of electromagnetic energy on the move. Since we detect this energy as it comes from across the vacuum of space, we must conclude that they exist in the free vacuum. A photon (as it travels) does not need to react with anything. It is its own wave. Many forms of energy transfer require a medium to transport them. Sound, for example, is a compression wave traveling through air. However, light does not need a separate medium to carry the wave — it carries its own wave. An alternative way of looking at this is to say that the medium is the fabric of space-time itself. But that is only a mathematical ploy to help understand the equations.
