Welcome to Quantum Magazine's podcast.

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

I'm Susan Vallett.

In a series of breakthrough papers, theoretical physicists have come, oh, so close to resolving the black hole information paradox that has toyed with

them for nearly 50 years. They now say with confidence that information does escape a black hole.

Imagine that you jump into a black hole. It seems like you might be gone with a poof,

but you won't be gone for good. Particle by particle, the information needed to reconstitute your body will reemerge.

Most physicists have long assumed it would.

That was the upshot of string theory, their leading candidate for a

unified theory of nature. But even though the new calculations are inspired by string theory,

they stand on their own. Information gets out through the workings of gravity itself, just ordinary

gravity with a single layer of quantum effects. This is a peculiar

role reversal for gravity. Einstein's general theory of relativity says the gravity of a black

hole is so intense that nothing can escape it. Stephen Hawking and his colleagues in the 1970s

developed a more sophisticated understanding of black holes,

but it didn't question this principle.

Hawking and others tried to describe matter in and around black holes using quantum theory,

but they continued to describe gravity using Einstein's classical theory.

It's a hybrid approach that physicists call semi-classical. Although the approach predicted new effects at the perimeter

of the hole, the interior remained strictly sealed off. Physicists figured that Hawking had nailed

the semi-classical calculation.

Any further progress would have to treat gravity as quantum.

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