In order to explore the nature of photons, no doubts can be allowed to exist concerning the “physics of photons”. While static gravitation plays no role in the physics of photons, this paper will show that the previously unknown nonbaryonic dynamic gravitation of photons determines not only the external physical behaviour of photons but also, in particular, the hitherto unknown physical events occurring within the photons themselves. For this reason, the paper places particular emphasis on dynamic gravitation as a new hitherto unknown physical quantity. Moreover the new type of gravitation postulated here also provides a plausible explanation of the mysterious nonbaryonic dark matter. As no generally accepted scientific explanation of the creation and essence of dark matter exists to date, it is to be anticipated that the nonbaryonic dynamic gravitation of photons is of general interest to physicists as well as cosmologists and may serve to initiate a general debate among them. Furthermore, this paper will also show that there exists a close mutual relationship between electrodynamics <> dynamic gravitation <> static gravitation <> electrostatics <> electrodynamics (refer to paragraph 4). Due to the fact that the insights into the relationship between photons and their dynamic gravitation have not been described by any other author to date, there exists only a few references that I can cite in support of my paper.