Or did he make it up? (Part – 1)

By : Niranjan Kambi, University of Wisconsin-Madison, USA

An Indian minister recently brought gravity into the limelight when social media made fun of him for his apparent ignorance about who discovered gravity. I’m going to be provocative and question the premise behind the question of whether gravity was indeed discovered. I am sure most people would doubt my sanity for asking this question. But, let’s play this game and see where it leads.

So, did Isaac Newton really discover gravity? Or did he invent it?

Since discovery assumes the phenomenon existed before it was explained, we can say gravity existed long before Newton without anyone rolling their eyes at it, right? Can we, though? 

Let me start with a passage from the iconoclastic philosophical fiction Zen and the Art of Motorcycle Maintenance, or ZAMM, by Robert Pirsig to set the tone. 

“For example, it seems completely natural to presume that gravitation and the law of gravitation existed before Isaac Newton. It would sound nutty to think that until the seventeenth century there was no gravity.”

“Of course.”

“So when did this law start? Has it always existed?”

John is frowning, wondering what I am getting at.

“What I’m driving at,” I say, “is the notion that before the beginning of the earth, before the sun and the stars were formed, before the primal generation of anything, the law of gravity existed.”

“Sure.”

“Sitting there, having no mass of its own, no energy of its own, not in anyone’s mind because there wasn’t anyone, not in space because there was no space either, not anywhere…this law of gravity still existed?’”

Now John seems not so sure.

“If that law of gravity existed,” I say, “I honestly don’t know what a thing has to do to be nonexistent. It seems to me that law of gravity has passed every test of nonexistence there is. You cannot think of a single attribute of nonexistence that that law of gravity didn’t have. Or a single scientific attribute of existence it did have. And yet it is still ‘common sense’ to believe that it existed.”

Let’s understand how Newton came upon gravity and see if it was discovered or if he made it up. The story begins with Galileo Galilei, who asked the most obvious of questions that nobody had bothered to wonder about until then: what makes objects, from a small ball to giant stars and planets move?

What he observed was the simple yet remarkable fact that objects moving in a straight line at a uniform speed will keep moving at that speed for eternity if left undisturbed. Now this is what we learn in elementary physics textbooks. But why should objects behave this way? Turns out we have no idea but since Galileo we have accepted this enigma of inertia without question. Here starts the mystery that underlies the most basic thing we know about objects in the world. 

To be continued… Next Week