Coffee and Gravity

Robert Hooke was a brilliant mathematician and natural philosopher. From 1664 until his death in 1703, he was the Gresham Professor Geometry at Oxford. Among his many accomplishments, he contributed to Boyle’s Law, helped found the Royal Society of Science, and helped lay out the city of London after the Great Fire of 1665.

Christopher Wren made his living as the Savilian Professor of Astronomy at Oxford, but he is best known for his work as an architect. While Hooke was working on rebuilding the city of London after the Great Fire, Wren was actually doing it. He built St. Paul’s Cathedral and designed or built fifty other churches in London.

Edmund Halley was a brilliant youth when he graduated from Oxford in 1676. He traveled to Saint Helena in the Atlantic and there observed a transit of Mercury. He laid the groundwork for calculating the size of the solar system (a project not completed in his lifetime) and predicted the return of the comet that now bears his name.

In January of 1684, the three men were sitting in a coffee house arguing over the function of gravity on the planets. Everyone knew gravity worked. The great Florentine natural philosopher Galileo Galilei had demonstrated this beyond question in the previous generation. A century before Galileo, Nicolaus Copernicus had demonstrated that the planets orbited the sun. But what shape would the planets orbits be? How would gravity affect large bodies like a planet?

Halley, the youngest of the men, believed that gravity would decrease with the inverse square of the distance. Hooke claimed he had done the math and that this was indeed the case. He claimed that the shape of the orbits would be elliptical. Wren was doubtful and demanded that Hooke show him the math. He even offered up one of his most prized and valuable books as a prize. Hooke could not show his work, and the prize went unclaimed.

Later that year, Halley went to visit the eccentric Lucasian Professor of Mathematics at Oxford’s rival, Cambridge – Isaac Newton. Newton was an odd man, completely consumed by scientific and mathematic pursuits. Sitting among papers and experiments, he listened to Halley as the young man presented his question. He then stated plainly that he had done the work and that it was here somewhere, and that Halley was correct.

Unable to find his calculations, Newton set to redoing them. He produced them and sent it to Halley, who was overjoyed to prove Wren wrong. The orbits would indeed be elliptical. Gravity would draw the planets toward the sun, but then their acceleration would send them slingshotting around the sun and then back out until gravity pulled them back again.

But something clicked in Newton’s brain, and he continued work on the theorem. Three years later, in 1687, he produced a book – the book. It was called Philosophiae naturalis principia mathematica or “Mathematical Principles of Natural Philosophy.” It was, in every sense of the word, the first true book of science. In short, Newton’s book changed the world as we know it forever. It is one of the greatest books ever written, and it made Isaac Newton’s name a shorthand for genius.

There are two morals to this story:

1. Great things happen when geeks, nerds and mathematicians drink coffee, even when their conversations don’t make sense to anyone else.

2. Make friends with guys from rival colleges, because sometimes they turn out to be really, really smart.

3. Always show your work.

Oh wait, that’s three morals…I never was any good at math.


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