The elastic property of the field is responsible for both gravity and electromagnetic forces.

The details of gravity force equations for photons are in the link below.

“Equations of force between photons or photon and matter with mass” The preprint published on March 27, 2020   Max Gaofei Yan     Abstract   This paper defines the gravitational field as a medium with elastic properties, and the gravitational force occurs when… Continue Reading
  A comparative examination of cosmological observations through three theories Alexander Z. Yan   Traditional Newtonian physics cannot explain many observed galactic-scale gravitational effects and phenomena. This has… Continue Reading The preprint published on May 11 2020   Alexander Z. Yan*, Max Gaofei Yan 300 NE 12th Ave. Apt. 601 Hallandale Beach, FL 33009-4503, USA; * Received 2020 May 6   ABSTRACT Recent studies showed that gamma-… Continue Reading