Mass is proportional to gravity because everything with mass emits tiny particles called gravitons. These gravitons are responsible for gravitational attraction. The more mass, the more gravitons. The properties of gravitons are thought to be responsible for the propagation of gravity: Changes in gravitational fields propagate by gravitational waves, which move at the speed of light.
GRAVITY propagates via gravitons; there is a graviton-graviton interaction.
Gravity is affected by intense gravitational fields around black holes.
Gravitons are fully expected to emerge as a consequence of gravity being an inherently quantum force in nature. Just as light is composed of photons, gravitational waves ought to be composed of gravitons. A series of particles moving along circular paths can appear to create a macroscopic illusion of a wave. Others have postulated that graviton scattering yields gravitational waves as particle interactions yield coherent states. Although these experiments cannot detect individual gravitons, they might provide information about specific properties of the graviton.
Forget gravitons; they are not pertinent to whether gravity acts on itself. And the answer is a resounding yes. Gravitation, unlike electromagnetism, is a “nonlinear” theory; that is to say, it is a theory in which the field interacts with itself. The gravitational field has energy and momentum, which are the sources of gravitation. This is explicitly present in Einstein’s field equations, particularly when the equations are written as useful approximations, the so-called post-Newtonian formalism. One of the contributions that pops up at the post-Newtonian level characterizes this nonlinearity.
Believe it or not, this is readily tested in the first “classical test” of general relativity, the anomalous perihelion advance of Mercury. If gravitation were a linear theory, the calculated perihelion advance of Mercury would be 4/3 the observed value. Instead, the value we observe is consistent with Einstein’s theory, with its known nonlinearity.
Now about gravitons. We don’t know if gravitation can be described as a quantum field theory, but we do know that if it can, in the perturbative limit, it will have quantized units of energy, i.e., gravitons. Also, in the perturbative limit, its interactions could be described, e.g., in the form of Feynman diagrams showing how gravitons interact with other particles.
Or with other gravitons. A quantum version of Einstein’s theory would have graviton vertices in its Feynman diagrams, showing gravitons emitting, absorbing, or scattering off gravitons. Similar diagrams do not exist for photons because electromagnetism is a linear theory. Gravity propagates via gravitons; is there a graviton-graviton interaction?
Gravity is caused by intense gravitational fields around black holes.
Fields of gravitational waves as particle interactions yield coherent states.[25] Although these experiments cannot detect individual gravitons, they might provide information about specific properties of the graviton.
Gravitation, unlike electromagnetism, is a “nonlinear” event; that is, it is a theory in which the field interacts with itself. The gravitational field has energy and momentum, which are the sources of gravitation. This is explicitly present in Einstein’s field equations, particularly when the equations are written as useful approximations, the so-called post-Newtonian formalism. One of the contributions that pops up at the post-Newtonian level characterizes this nonlinearity.
Believe it or not, this is readily tested in the first “classical test” of general relativity, the anomalous perihelion advance of Mercury. If gravitation was a linear theory, the calculated perihelion advance of Mercury would be 4/3rd the observed value. Instead, the value we observe is consistent with Einstein’s theory, with its known nonlinearity.
Now about gravitons. We don’t know if gravitation can be described as a quantum field theory, but we do know that if it can, in the perturbative limit, it will have quantized units of energy, i.e., gravitons. Also, in the perturbative limit, its interactions could be described, e.g., in the form of Feynman diagrams showing how gravitons interact with other particles.
Or with other gravitons. A quantum version of Einstein’s theory would have graviton vertices in its Feynman diagrams, showing gravitons emitting, absorbing, or scattering off gravitons. Similar diagrams do not exist for photons because electromagnetism is a linear theory.
Forget gravitons, as they are not pertinent to the question: Does gravity act on itself? And the answer is a resounding yes. Gravitation, unlike electromagnetism, is a “nonlinear” theory; that is to say, it is a theory in which the field interacts with itself. The gravitational field has energy and momentum, which are the sources of gravitation. The so-called post-Newtonian formalism is explicitly present in Einstein’s field equations, particularly when the field equations are written as a valid approximation. One of the contributions at the post-Newtonian level characterizes this nonlinearity.
Believe it or not, this is readily tested in the first “classical test” of general relativity, the anomalous perihelion advance of Mercury. If gravitation were a linear theory, the calculated perihelion advance of Mercury would be 4/3 the observed value. Instead, the value we observe is consistent with Einstein’s theory, with its known nonlinearity.
Now about gravitons. We don’t know if gravitation can be described as a quantum field theory, but we do know that if it can, in the perturbative limit, it will have quantized units of energy, i.e., gravitons. Also, in the perturbative limit, its interactions could be described, e.g., in the form of Feynman diagrams showing how gravitons interact with other particles.
Or with other gravitons. A quantum version of Einstein’s theory would have graviton vertices in its Feynman diagrams, showing gravitons emitting, absorbing, or scattering off gravitons. Similar diagrams do not exist for photons because electromagnetism is a linear theory.
Mass is proportional to gravity because everything with mass emits tiny particles called gravitons. These gravitons are responsible for gravitational attraction. The more mass, the more gravitons. The properties of gravitons are thought to be responsible for the propagation of gravity: Changes in gravitational fields propagate by gravitational waves, which move at the speed of light.
Mass is proportional to gravity because everything with mass emits tiny particles called gravitons. These gravitons are responsible for gravitational attraction. The more mass, the more gravitons. 
