May 7 - Happy Birthday, Alexis Claude Clairaut

Posted on May 7, 2021

Key points

This is an update of my post published on May 7, 2010:

On this date in 1713, a mathematical prodigy was born in Paris, France.

Or was in on May 3, 1713, that Alexis Claude Clairaut was born?

Or May 13?

I found all three dates as I looked at various biographies of Clairaut. So I checked 12 different websites, assuming that one of the dates would be reported on most of the sites and would therefore (hopefully) be the accurate birth date.

But four websites said May 3, four said May 7, four said May 13!

So this number guy, this fellow who was soooo good with numbers, has three different numbers associated with his birth!

They can’t all be “right.”

On the one hand, who cares? He was born in the first half of May. While he was alive, he may well have celebrated his birthday on a convenient day rather than the “actual” birthday (assuming that he knew the accurate birthday!).

On the other hand, could there be an explanation for why these different dates are floating around? Is it as simple as a mistake in copying? Did some sources just copy-paste what they found elsewhere, without checking its accuracy? Could it be that the variation comes from the world’s uneven switching over from the Julian calendar to the Gregorian calendar? Is the birth date itself unrecorded, and all we have is the baptismal date—and then various scholars made different assumptions about the actual birth date?

I have no idea!

Okay, what about the rest of the life of this “numbers guy”? He was a child prodigy, right?

A prodigy is someone who has exceptional talent at something, and a child prodigy is one whose exceptional talent is recognized at an early age. Mozart was a child prodigy in music, and Clairaut was a math prodigy.

He learned to read by reading Euclid’s Elements, he mastered calculus and analytical geometry by age 9, and he read his first mathematical paper to the Academy at age 13! At age 18, he became the youngest person ever elected to the Paris Academy.

Those are some amazing numbers, huh?

Another number associated with Clairaut’s life is very sad—his mom and dad had 20 kids, but he was the only one who survived to adulthood.

Clairaut’s contributions

Clairaut was considered a human computer, and he used his number skills to do a lot of important things:

He questioned and then supported Newton’s theory of universal gravitation.

He better computed the Moon’s orbit around Earth and the orbit of Halley’s comet around the Sun.

He confirmed the shape of the Earth (which is not a perfectly round sphere, like an artificial globe, but instead is slightly squashed down at the poles into an “oblate spheroid.”