The dispersed medium of the electromagnetic field fills the whole space. We are convinced of the existence of this environment whenever we bring a mobile phone to our ear. The quanta of this medium - vortex gravitons - continuously move with a "thermal" speed of ~ 3 * 10 ^ 8 m/s (speed of light).
Photons are stable annular vortices of an electromagnetic field (Helmholtz vortices). They move along the axis of symmetry in a field medium without performing work. Photons are in "thermal equilibrium" with the medium - their speed is equal to the speed of light.
This situation is similar to the speed of sound in the atmosphere. Modern rockets move at hypersonic speeds with sufficient power. The velocities of matter during supernova explosions and in jets also exceed the speed of light.
The theory of relativity "prohibits" movement at superluminal speeds due to an increase in relativistic mass (mass of the boundary layer of the field). There is no mysticism here. The resistance of the field medium is manifested at light speeds. Body weight remains unchanged.
More in the book "Electromagnetic Gravity" in my profile.