[muffaletaman]

You are confusing instantaneous with continuous.

The effect of Gravity as a field is based on a continuous "warping" of space based on the presence of mass. And mass such as the sun does not instantaneously dissappear, as in the thought experiment cited of a vanishing sun. Every "now" is based on the influence of where everything elsewhere "was" at this moment's light-horizon...

If the sun exploded from its center in an emmense explosion such that all the remaining mass of the sun was accelerated into a spherical shell expanding at near light speed from the center of the sun, once this shell of matter passed the earth, what was left of the earth would proceed in an essentially straight line - no longer an orbit - based on the long-recognized zeroing out of the gravitational attraction of matter outside a sphere, modified by the reaction of the collision of the expanding debris impacting the earth, and physically propelling it in a slightly different direction...

[muffaletaman]

Likewise the importance that as near as it can be measured, inertial mass and gravitational mass are exactly equal.

In the supposed experiment measuring the weight of an object suspended over a rapidly spinning superconducting disk, and finding the claimed finding that weight of the object is lessened...

(1) either a repulsive electromagnetic effect is generating a force upward... normal action/reaction is occuring, nothing more...

(2) or a method of shielding the gravity field is being generated, which if true can be engineered into a warp drive someday allowing interstellar travel vis-a-vis star trek (i.e. if gravitational mass and inertial mass can be caused to become different and the difference manipulated, then perhaps an inertial bubble can be created, and the bubble accelerated by a generated polar flux in the universal G-field - one direction of the entire universe attracts, the opposite direction repulses. Thus, though the object within the bubble never exceeds local light speed within the bubble, the bubble itself can be moved at warp speeds, multiples of the speed of light)...

(3) or... (fill in the blank yourself...)