Three groups of cicadas emerge together for first time in 1,547 years Premium

North American cicadas have life cycles that last for prime numbers of years, putting pressure on the idea that humans created mathematics.

It’s a big year in America – for wildlife as well as for politics. I’m talking about periodical cicadas.

These curious creatures spend most of their lives in the ground, emerging after 13 or 17 years to eat, breed, die and repeat the cycle. For the first time in more than 200 years, two specific broods of the 13- and 17-year cicadas have emerged together: Brood XIX, in the southeastern United States, and Brood XIII, found in the country’s Midwest.

What’s more, this time the emergence of these broods also happens to coincide with an unrelated event on the other side of the world: the emergence of a big batch of Australian greengrocer cicadas, which have a seven-year life cycle.

This remarkable event has been 1,547 years in the making. Thinking about it sheds light on some of the deepest questions about mathematics.

Are mathematical facts created or discovered? Ask a mathematician, and they are likely to tell you that mathematical facts are discovered.

But this is perplexing: if such facts are discovered, what are we discovering? Are mathematical facts somehow “out there” before we discover them? Does that mean there’s some realm of pure mathematics that we uncover with our minds?

These sorts of questions quickly begin to feel pretty uncomfortable. We find ourselves in deep metaphysical territory, beset by questions about the nature of reality.