Gravity Travels at the Speed of Light

Here's the rub. In Newton's theory of gravity, one body exerts a gravitational pull on another with a strength determined solely by the mass of the objects involved and the magnitude of their separation. The strength has nothing to do with how long the objects have been in each other's presence. This means that if their mass or their separation should change, the objects will, according to Newton, immediately feel a change in their mutual gravitational attraction. For instance, Newton's theor...

 Newton's Law of Universal Gravitation

Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them

 A Unique Statement of the Law of Universal Gravitation

The relative interattractiveness invisibly operative between any two remote-from-one-another cosmic bodies, as compared to any other pair of cosmic bodies, equally distanced from one another, is proportional to the multiplicative product of the respective couple's masses, and the interattractiveness of any pair of celestial bodies varies inversely as the second power of the distance between them. Halve the intervening distance and the interattractiveness increases fourfold.