Why I can’t get excited about the new largest known prime

A week or two back, it was announced that computers had verified that $2^{74,207,281}-1$ was a 22-and-a-bit million digit prime number. Cue headlines on the BBC and silliness on Twitter and slight derailment of maths lessons across the country.

But me? It leaves me cold, and here’s why: because of Sergei Bubka.

In the 1990s, Sergei Bubka had an agreement with Nike that every time he broke a pole-vaulting world record, they’d pay him $100,000. And he duly beat his world record, over and over again, one centimetre at a time.

Bubka was an incredible athlete, obviously. But the same person not-even-inching a world record upwards on a regular basis using the same techniques doesn’t hold any particular thrall for me. “Oh, Bubka’s broken another world record. Hooray.”

Worse than that, in the case of the primes, while the bar is being raised by looking for bigger primes, it’s being lowered just as swiftly, as computing power increases.

Worse still, in this case, the discovery went unnoticed for several months. It’s as if poor Sergei broke his own world record yet another time and the officials didn’t record it. (In this analogy, Sergei is the computer tirelessly running the Lucas-Lehmer test over and over again. The officials are the people whose job it is to keep track of what he’s done and take credit for it. That’s right: the people with their name all over the press are the people who missed the thing they were meant to be looking out for.)

I’m not saying that showing this monster is a prime1 isn’t an achievement, I just don’t think it’s very interesting. I wouldn’t expect the New York Times to give Bubka prominent coverage every time he broke a world record, to the exclusion of the different athletes breaking records in other events.

We’ll get exactly the same big prime story again in a couple of years, and I’ll continue to shrug at it.

There are some positives, of course: it’s not a daft story about the perfect formula for the ideal rugby match, and it’s not a pseudo-scientific claim that slugs can do calculus, so that’s something. The GIMPS is an interesting bit of computer science (with, presumably, a bit of number theory behind it).

But I don’t buy “it gets people talking about maths” as a justification for this story, any more than I buy it as an excuse for ‘perfect formula’ stories.

I’ll not stop your “new prime” parties; I couldn’t if I wanted to. But forgive me if I stay at home and put my computer to a more constructive use.

Colin

Colin is a Weymouth maths tutor, author of several Maths For Dummies books and A-level maths guides. He started Flying Colours Maths in 2008.

He lives with an espresso pot and nothing to prove.

  1. I don’t think saying the number has been ‘discovered’ is accurate. I can ‘discover’ as many Mersenne primes as I like by making a huge list of the Mersenne numbers. Some of them are bound to be prime. []

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