Gravitational field

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The gravitational field is a field (physics), generated by massive objects, that determines the magnitude and direction of gravitation experienced by other massive objects.

According to Einstein's physics the physical reason for this field is that space and time (composing together spacetime) are modified by the presence of masses (actually by any form of energy in space) so that speed of light becomes a tiny bit smaller around these masses (as demonstrated by bending of light rays in their vicinity) and so the internal energy of any object, known also as its gravitational energy, is smaller in direction of those masses. This way the object, trying to get into place of smaller internal energy is pushed in direction of those masses by an inertial force, called in this case a gravitational force generated by its own mass. As calculations show, this force is almost exactly equal the gravitational force proposed by Isaac Newton over 300 years ago. Except that it is an "Einsteinian push" coming from the inertia of the object itself that directs the object to a place where its internal energy is smaller and not a "Newtonian attraction" of the other masses. So the physics is different but math almost exactly the same. The "Einsteinian push" is a bit more accurate math than "Newtonian attraction" but the differences are negligible for all practical purposes within our solar system.

The gravitational field at any point in space is by definition the ratio of the gravitational force acting on any object located at this point in space, to the mass of this object.