With Kent Harrison, Kip Thorne and Masami Wakano he wrote Gravitation Theory and Gravitational Collapse (1954).
The fact that, so far as is known, gravitation depends on no other physical factors makes it likely that the value of G reflects a basic restriction on the possibilities of physical measurement, just as special relativity is a consequence of the fact that, beyond the shortest distances, it is impossible to make separate measurements of length and time.
After introducing the idea of a universal force affecting all objects no matter how insulated, and noting that gravitation as usually conceived is such a force, Reichenbach writes that: "The solution to the problem of space is…found only in this conception we call conventionalism…which goes back to Helmholtz and Poincaré." (Reichenbach, 2006, p. 135).
Newton's theory of gravitation worked virtually perfectly for weak gravitational fields.
Three-body problem, in astronomy, the problem of determining the motion of three celestial bodies moving under no influence other than that of their mutual gravitation.
By the start of the 21st century, all observations and experiments on gravitation had detected that there are no deviations from the deductions of general relativity, that the weak principle of equivalence is valid, and that the inverse square law holds over distances from a few centimetres to thousands of kilometres.
Newton himself made no attempt to communicate his theories of motion and gravitation to general readers.
For example, to many in the seventeenth century, Newton's account of gravitation, involving action at a distance with no underlying explanation, seemed a poor account, in that respect at least, when compared, for example, to Ptolemy's explanation of the motion of the planets in terms of contiguous crystalline spheres or to Descartes' explanation in terms of vortices.
For an inverse-square law such as Newton's law of universal gravitation, where n equals 1, there is no angular scaling (k = 1), the apsidal angle α is 180°, and the elliptical orbit is stationary (Ω = β = 0).
The effect of gravitation on light increases with the strength of the gravitational attraction.
