Welcome to Quantum Magazine's podcast.

Each episode, we bring you stories about developments in science and mathematics.

I'm Susan Vallett.

In the fall of 2019, the world began one of the largest evolutionary biology experiments in modern history.

Somewhere near the city of Wuhan in eastern China,

a coronavirus acquired the ability to live inside humans rather than the bats and other mammals that had been its hosts. It adapted further to become efficient at spreading from one person to the

next, even before the

body's defenses could rise against it. The evolutionary chess game didn't stop there. We have a

Greek alphabet soup of SARS-CoV-2 variants to prove it. Researchers around the world are trying

to understand the virus's evolution in more

detail. That's next.

Imagine you're in a lab where you've synthesized ancient DNA sequences and spliced them into modern bacteria

just to see how they'd react.

They needed each other, but they didn't want each other.

So, you know, it was like a very complicated relationship

unfolding in front of me.

This isn't Jurassic Park or some sci-fi movie.

I'm Steve Strogetz, and this is the joy of why. A new podcast from

Quantum Magazine that takes you into some of the biggest unanswered mysteries in science and math

today, where the knots with three crossings, the type you know from your shoelaces, are just the

beginning of a much bigger story. There's one four crossing knot.

There are two five crossing knots. We've tabulated all the possible knots up to 19 crossings,

...