We are familiar with the idea that mass and energy are equivalent from the famous equation E= mc². If mass and energy are one and the same, why do we need two different forces- gravitational and electromagnetic?
As photons ‘aggregate’ into matter, the resultant decrease in the number of ‘free photons’ or the energy level of the system (or the decrease in entropy) is probably what we appreciate as the gravitational attraction. And energy may be seen as a force that is responsible for the gravitational repulsion or antigravity.
In other words an increase in entropy (energy level or disorder) is what causes the electromagnetic force and a decrease in the same (or creation of matter) is what results in the gravity.
A decrease in entropy may create ‘antiphotons’ (?graviton) or ‘dark energy’ which could then mediate gravity.
Or Gravity could be an innate property of matter in the universe in the sense that it may not require a mediator or carrier. Probably matter ‘naturally’ collapses into singularity in the absence of Energy. So graviton, the presumed carrier particle for gravity, may not be needed.
So mass and energy are responsible for the same force but have opposite direction.
Gravitational collapse/ Formation of Black holes
It is thought that stars as they ‘burn out’ their energy reserves, collapse into bodies called neutron stars, white dwarfs and black holes depending on their mass. That means a star needs energy to oppose its own gravity and without this energy it collapses.
If we take the Solar system, while the Sun and the planets get ‘attracted’ by the gravity, the energy that ‘pervades’ the solar family opposes their gravitational collapse. This energy includes the Sun’s radiation, the planets’ energy, and probably the ‘vacuum energy’. So if Sun runs out of its energy reserve, this not only results in its own collapse but probably of the whole solar family.