Welcome to the Qantascience podcast.

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

I'm Susan Vallett.

Using machine learning, string theorists are finally showing how microscopic configurations of extra dimensions translate into sets of elementary particles,

though not yet those of our universe. That's next.

It's season three of the joy of why, and I still have a lot of questions. Like, what is this thing we call time? Why does altruism exist? And where is Jan 11? I'm here. Astrophysicist and co-host. Ready for anything. That's right. I'm bringing in the A team. So brace yourselves. Get ready to learn. I'm Janelle Levin. I'm Steve Strogatz.

And this is Quantum Magazine's podcast, The Joy of Why.

New episodes drop every other Thursday.

String Theory captured the hearts and minds of many physicists decades ago because of a beautiful simplicity.

The theory goes like this.

Zoom in far enough on a patch of space, and you won't see a menagerie of particles or jittery quantum fields.

There will only be identical strands of energy, vibrating and merging and separating.

By the late 1980s, physicists found that these strings can cavort in just a handful of ways.

That raised the possibility that physicists could trace the path from dancing strings to the

elementary particles of our world. The deepest rumblings

of the strings would produce gravitons. Those are hypothetical particles believed to form the

gravitational fabric of space time. Other vibrations would give rise to electrons, quarks,

and neutrinos. String theory was dubbed a theory of everything.

Anthony Ashmore is a string theorist at Sorbonne University in Paris.

People thought it was just a matter of time until you could compute everything that was to know about these things

and then just compute predictions in your particle physics theory directly from string theory.

But as physicists studied string theory, they uncovered a hideous complexity.

...