Is 'surface gravity' the same as 'gravitational field strength'? No , it isn't . The first is gravitational field strength at the surface of the Earth . The second is a general term , that refers to the force a body exerts on a unit mass , kept at some distance , sa...
BIn GR gravity, does "equal and opposite" still hold and what does that mean? In GR, if two massive objects distort spacetime, are the effects still "equal and opposite" in some sense? In what sense? It seems that for "equal" to hold, the equations of GR must force the effect of ...
Take for example the simple Law of Gravity envisioned by Newton in 1660s that force of gravity equals the product of masses divided by the square of the distance between the two masses and multiplied by a gravitational constant. This very simple but prophetic mathematical formulation has been pro...
1920), supporting the factor of two increase in the deflection angle prediction of general relativity over Newtonian gravity. Should the Sun be counted as the first lens “discovery”? Throughout this chapter we will be concerned with strong gravitational lensing, in which multiple images of the ...
Although gravity and topography are both non-unique functions of 3D density structure, when taken together—since the vertical component of the gravity field is sensitive to 3D mass distribution and topography is sensitive to 2-D buoyancy—the two actually do prescribe a unique density structure. ...
In general relativity, the effects of both the stationary field and gravitational radiation are described by the tidal forces they produce on free test masses. In other words, single geodesics alone cannot detect gravity or gravitational radiation; we need at least a pair of geodesics. While the...
First John Mitchel, in a letter to Henry Cavendish in 1784, and later Johann von Soldner in 1804, calculated that light propagating in the field of a spherical mass M, like a star, would be deflected by an angle αˆ = 2GM/(c2ξ), where G is Newton's constant of gravity, c is...
In the string-inspired effective gravitational field theory for the very early Universe, proposed in [1,2,3], and further discussed from the point of view of the swampland criteria and the weak gravity conjecture in [4], it was assumed that the only degrees of freedom present are those fro...
> radiation, because gravity is such a weak force; it would take a truly > enormous amount of radiation to give a detectable signal. Â But it would be > very peculiar, to say the least, to find that some forms of electromagnetic > energy gravitate while others don't. > > > Is ...
This observation is due to the Event Horizon Telescope (EHT) based on the very large interferometry (VLBI) technique promise to get deep understanding of the strong gravitational field regime around supermassive black hole (SMBH) and to test the theories of gravity. The image of the SMBH or ...