When science reached Newton, science came up against that extraordinary Englishman...As an Englishman he postulated a rectilinear universe because the English always used the word "square" to denote honesty, truthfulness: in short, rectitude. Newton knew that the universe consisted of heavenly bodies that were in motion and that noneof them moved in straight lines, nor ever could. Mere fact will never stop an Englishman. Newton invented a straight line, and that was the "law of gravitation," and when he had invented this, he had created a universe which is wonderful in itself, a complete British universe, and established it as a religion which was devoutly believed for 300 years. --- George Bernard Shaw, 1930
Is Gravity a Straight Line?
If we drop an object, will it travel along a straight line to the ground? For all the appearances it might seem so. If we were standing at the equator and dropped a ball of something fairly heavy from a height of 32 feet, in just one second it would reach the ground. Would that have been a straight line? In that same second, as a consequence of the Earth’s rotation, it would have traveled nearly 1500 feet (over a quarter mile) toward where the Sun rises. (We will not, for simplicity, take into this account the additional motions of the solar system, galaxy, et cetera.) If we were standing at the poles... well, who but a madman would?
We can easily see that our object was not following a straight line. When we combine these two aspects of our observed motion, the one that appears to move straight earthward, and the other less apparent one, produced by the planet’s rotation, we will find that our object followed a curling curve of a path. In fact, it followed the type of line that an object being pulled into a fluid vortex would follow.
What is that inward force in the vortex called?
It is called CENTRIPETAL FORCE.
How is this force (as it appears in the fluid vortex) explained by the science of physics? Was this force ever described or explained by the Newtonian model?
Physics books, both advanced and basic, seem only to describe centripetal force in terms of a string attached to a weight, being slung about in a circle. This "string" is actually called "a," an acceleration in Newton's Second Law of Motion (F = ma -- where "F" is force and "m" is mass). There are no strings pulling objects into a vortex! A string is not the centripetal force of the vortex. Most books purporting to explain our knowledge of gravity haven't even the words, "centripetal" or "vortex" within them.
Is it time for us to begin writing some new books?
I really must say here that no serious disrespect is intended toward Sir Isaac Newton. Newton, explaining the nature of gravity in non-mathematical terms, said that gravity might be transmitted by an invisible æther. He further suggested that this æther may also be responsible for electricity, magnetism, light, radiant heat, and the motion of living things that he, like his contemporaries, thought was the consequence of some source beyond inanimate matter. It is upon all of us to stand upon Newton’s shoulders, only when it is judged advantagious. When the view is obscured from that vantage, it is time to find another viewpoint. Please take references to Newton as they were intended, with a sense of humor. Thank you. -- RLR