Gravitational lensing, as the term suggests, arises from the interaction between electromagnetic radiation (photons) and a gravitational field. Specifically, it involves the symmetric energetic interaction of photons with the gravitational field, resulting in balanced blueshifts and redshifts of the photon’s energy. This symmetry causes the photon’s trajectory to curve, deviating from its linear path during transit through the gravitational field. Once the photon exits the field, it retains its energy and resumes its inherent linear trajectory.
The question of whether energetic plasma can cause gravitational lensing must be examined by understanding how photons interact with ionized gas during transit. Unlike the photon-gravitational field interaction, which is energetically symmetric, the interaction between photons and ionized plasma is fundamentally different. This is an electromagnetic-electromagnetic interaction where photons interact with charged particles (electrons and ions) via electromagnetic forces.
Such interactions are inherently asymmetric and often involve absorption, scattering, or redistribution of photon energy due to the charged nature of plasma constituents. Consequently, these processes result in photon scattering rather than the curvature of the photon’s path seen in gravitational lensing.
While hot plasma may facilitate symmetric energy exchanges, it primarily causes photon scattering rather than maintaining the conditions necessary for gravitational lensing. This distinction highlights that the nature of photon interactions with ionized plasma differs fundamentally from the interaction with a gravitational field.
Electrons and ions, due to their electric charge, always interact with photons via electromagnetic forces. However, this interaction leads to scattering and absorption, making it unlikely that hot plasma could produce the phenomenon of gravitational lensing.
In conclusion, photon interaction with a gravitational field and photon interaction with ionized plasma are fundamentally different processes. Gravitational lensing remains a unique phenomenon tied to the symmetric energetic interaction of photons with gravitational fields, distinct from the asymmetric scattering processes characteristic of plasma interactions.