Welcome to Quantum Magazine's podcast.

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

I'm Susan Vallett.

Scientists have recently discovered scores of free-floating worlds that defy classification.

The new observations have forced them to rethink their theories of star and planet formation.

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

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

New episodes drop every other Thursday.

When Galileo Galilei, a mathematician at the University of Padua,

trained a spyglass of his own creation

on the sky, he was overwhelmed. He saw more than 500 new stars in the constellation Orion, in

addition to the familiar three in the hunter's belt and six in the sword. In October of

2023, astronomers used the James Webb Space Telescope to zoom in on

one of the middle stars in the sword and identified another 500 or so previously unseen spots.

The worlds are so small and dim that they blur the line between star and planet. It's an ambiguity that plagued Galileo,

who referred to the moons of Jupiter as both stars and planets in the same page in his 1610

astronomical treaties. And it continues to trouble astronomers today. Samuel Pearson is an astronomer

with the European Space Agency.

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