It is well established that in some experiments light behave like waves (electromagnetic) and in some experiments it behave like particles (photons). This is called wave particle duality. It is also well established that the gravity acts on both masses as well as energy. For the same reason Dark Energy in cosmology can exert gravitational pull and cause accelerated expansion of the universe. Previously physicists used to use relativistic mass for certain calculations. For light it is E/c^2. It comes from E= mc^2. But then general relativity physicists abandoned this parameter.

If you want to understand why a photon , a massless boson for sure, is affected by gravity exerted by stars, black holes etc, you have to put apart the Newton's theory for the moment, and move to the Einsteinian General Relativity where garvity means spacetime curvature and any free particle (including photons) follows a so-called geodesic (a trajectory which is curved in a curved space and linear in a flat space).

Withou General Relativity you can not understand how the trajectory of a massless particle can be bent by a vicinal mass.

according to the interpretation of gravity by general relativity, gravity is interpreted as a property of space-time in that , in general, energy-concentrations form space-time and the geodesics in space-time are the orbits, on which energy-comcentrations move. since photons are energy concentrations, they move on geodesics as well. for black-hole solutions in general relativity, these geodesics lead directly into the center of the black hole.

@Hinnerk Albert

Thank you, sir, your explanation is convincing.

Any theory is consistent until it can explain results of experiments. If the theory cannot explain some results, we can: 1) extend its frames by means of another theory, which can explain these results; 2) built the new in principle theory which will explain these results by means of new propositions. Quantum theory cannot explain the nature of entangled particles. Really, the explanation of this phenomena is out the frames of quantum mechanics. The problem i the same that is in GR. This theory rejects long-range-action. If to accept this phenomena, we will understand that the time is not x^4 = ict. We must accept that the Time is multi-dimensional space of the time, which creates all local times of different bodies including the particles. The notion entanglet particles means that the same particle possesses 2 sates in the Time. Therefore these particles are linked by the same state of the time as and in the initial moment.

I think the best way of thinking about this question is to recognise that mass curves spacetime. This is observed during a solar eclipse where it is clear that light from distant stars has followed a curved path around the sun. In a similar way the presence of a black hole will create a region of curved spacetime even outside the event horizon.

See also:

Data Black Holes

Richard

This question made me disappointed in physicists' definitions of natural phenomena in the universe, the subject of the fact that the photon does not have a mass. It was a solution in which physicists fabricated it to escape from his answer to a simple question from their students. If the photon has a mass and gravity, then why, according to Lorentz, does not reach the infinity in the mass? The professors were deceiving the students and that they themselves should say that the photon is massless. I have a solution if you read my paper on the transformation equations for the fifth dimension in this link:

https://aip.scitation.org/doi/abs/10.1063/1.4992770

How can you bend, curve.. "space-time"?? What is bent, curved,...?

JES

The best way i can think to get this question answered in a simple way which anyone can understand is to consider 2 bodies attracted by gravity to each other lets say one is the earth and the other is an apple

The apple will accelerate towards the earth at 1 g and the earth will hardly notice

If we spilt the apple in 2 the acceleration of the parts stays exactly the same at one g because the mass is halved and the force is halved

Continue doing this splitting until in the limit you have a photon there is no point in this scenario where the situation changes so in the limit the photon with zero mass and zero force follows the same path. There would have to be an additional singularly for this not to be the case.

Don’t forget space time itself is curved and the inertia of the mass which limits the acceleration to one G is an explanation we use to explain the motion of the bodies

I.e. if you double the mass the force doubles

This is only the result of space time being curved not the cause of space time being curved. I still think it was extra brilliant of Einstein to predict this would happen to a massless particle in advance of it being detected

The simple answer to the question of this thread is Einstein's formula E=mc². This formula means that any form of energy also corresponds to a gravitating mass.

Basically, this question is addressing only a small part of the problems of General Relativity and Quantum mechanics (the Big and the Small). The Black Hole is one of the intersections where models of both Big and Small must become one model. Certainly, the standard, accepted models fail. Most (all but the STOE) of the non-standard (not accepted by the orthodox community) also fail.

Scalar Theory of Everything (STOE) unites the big, the small, and the four forces (GUT) by extending Newton's model

https://www.researchgate.net/publication/344442808_Scalar_Theory_of_Everything_STOE_unites_the_big_the_small_and_the_four_forces_GUT_by_extending_Newton's_model

https://www.youtube.com/watch?v=0YlJGdTvuTU

The STOE explanation is the photon are particles. Their structure allows the computer simulation to duplicate light interference experiments include those several experiment which specifically reject wave models of light. It also describes why photons have the fastest speed of any other matter and a much better explanation of the Michaelson-Morley experiment.

Matter includes substance and fields, including electromagnetic ones. Particles of substance move at subluminal speeds, particles (quanta) of the electromagnetic field move at the speed of light. Black holes have gravitational fields with extremely strong gravitational effects. According to the theoretical studies of Laplace and Hilbert, a black hole is an object, the gravitational field can accelerate a material object to motion at the speed of light. As we approach the surface of a black hole, the rate of time slows down until it stops completely on its surface. Black holes absorb material bodies, accelerating them to the speed of light, that is, transforming them into fields. Btcause photons move with the the light velocity, black hole absorbs photons.