Hooke and Newton
In most textbooks, Sir Isaac Newton is credited with the Law of Universal Gravitation. While many would agree with this statement, there are many others who would argue that Robert Hooke deserves the credit and not Newton. Take a look at the following pieces of evidence and decide for yourself. Who deserves the credit, Newton or Hooke?
23 May 1666, during a demonstration at the Royal Society Hooke proposed his theory of the planetary movements:
“This inflexion of a direct motion into a curve by a supervening attractive principle.”
London, in 1670, R. Hooke during a seminar at the Royal society:
“First, thats all Cœlestial Bodies whatsoever, have an attraction or a gravitating power towards their own Centers, whereby they attract not only their own parts, and keep them from flying from them, as we may observe the Earth to do, but that they do also attract all the other Cœlestial Bodies that are within the sphere of their activity; and consequently that not only the Sun and Moon have influence upon the Body and motion of the Earth, and the Earth upon them. . . ”
Hooke announced in 1674 that he planned to "explain a System of the World differing in many particulars from any yet known", based on three "Suppositions": that "all Coelestial Bodies whatsoever, have an attraction or gravitating power towards their own Centers" [and] "they do also attract all the other Coelestial Bodies that are within the sphere of their activity";that "all bodies whatsoever that are put into a direct and simple motion, will so continue to move forward in a straight line, till they are by some other effectual powers deflected and bent..."; and that "these attractive powers are so much the more powerful in operating, by how much the nearer the body wrought upon is to their own Centers".
In winter, 1679, Hooke became then secretary of the English Royal Society and he introduced a correspondence with Isaac Newton. His intention was sincerely to interest Newton in the works of the Academy. He ended however his first letter by asking to Newton for his opinion on his past works of celestial mechanics.
17 January 1680, Hooke in a letter to Newton:
“. . . it now remains to know the proprieties of a curve Line (not Circular nor concentrical) made by a central attractive power which make the velocity of Descent from the tangent line or equal straight motion at all Distances in a duplicate proportion to the Distances Reciprocally taken. I doubt not but that by your excellent method you will easily find out what Curve must be, and its proprieties, and suggest a Physical Reason of this proportion”.
Newton in a June 20, 1686 letter to Halley:
“... Borell did something in it and wrote modestly, [Hooke] has done nothing and yet written in such a way as if he knew and had sufficiently hinted all but what remained to be determined by the drudgery of calculations and observations, excusing himself from that labour by reason of his other business: whereas he should rather have excused himself by reason of his inability. For it is plain by his words he knew not how to go about it. Now is not this very fine?”
Newton’s Philosophiae Naturalis Principia Mathematica was published in 1687 and contained the Law of Universal Gravitation.
Halley to Newton after Principia’s publication:
“… That Mr. Hook has some pretensions upon the invention of the rule of the decrease of Gravity, being reciprocally as the squares of the distances from the Center. He sais you had the notion from him, though he owns that Demonstrations of the Curves generated thereby to be wholly your own…”
So, who do you think deserves the credit? Does coming up with the idea earn you the credit, or should you be able to demonstrate the validity of the idea in order to deserve the credit? If working in a group, discuss these questions. Then, write a letter stating your conclusion. Support your conclusion with evidence.