There's something in our galaxy that shouldn't be there. It doesn't shine. It doesn't speak. But it warps time, bends space, and swallows light whole. Scientists once thought the very idea was too preposterous to be real. Now it might be the reason that you're here listening and watching this podcast. It's called a black hole. But what if black holes aren't just the universe's ultimate predators? What if they're also its midwives? What if every black hole is a kind of cosmic womb giving birth to a new universe with slightly different laws of physics in a process not unlike natural selection? Today's guest has spent years tracing the story of how we came to learn about black holes and not just the science, but the human struggle to comprehend these magnificent monsters of the cosmos.

From equations scribbled in the trenches of World War I to a vanishing dark star in the nineteen seventies that changed everything. Marcus Chan, today's guest, is one of the clearest voices in popular science writing that I know of in the known universe. And his latest book, A Crack in Everything, tells the astonishing story of how black holes went from absurd fantasy to the center of all we know. Marcus soon, I wanna ask you if black holes are actually creators, a type of force that acts as a womb perhaps for new universes, but certainly for solar systems like our own. But first, let's start where everyone starts, as black holes as destroyers of worlds. What makes black holes the most terrifying objects in the cosmos?

Well, the regions of space where, gravity is so strong that nothing, not even light, can escape. So they do have this reputation for sucking in material relentlessly. And this was, really a a big mistake that that physicists and astronomers made over the last century because they thought that they would just suck in material, They're black against the black of space, and they'd be actually impossible to see. But actually, one of the most striking features well, first of all, black holes the the black holes that we know of in the universe are are include some of the most luminous objects in creation so that they're far from being black. And although we can just about see material disappearing down the the whole of a black hole just about, the most striking feature is often of material coming out, you know, often along these titanic jets of material which stab out through galaxies for millions of light years. So really, you know, the idea of them sucking in material, is is kind of they do, but but actually they kind of defy that that picture. And that's basically because they're they're embedded in environment and physicists and astronomers assume that that that they would be black because they would be isolated. But in fact pretty much everything in the universe is embedded in environment.

Most stars are binary stars. You know, sun is quite unusual being a solitary star. It's quite unusual. And being embedded in an environment, having a companion, having gas or dust around you makes all the difference. And this leads to these objects being in fact incredibly luminous even though they're black holes.

One thing I really loved about your writing, I always love your writing, but, but about the book is that you kind of steer away from the kind of pop culture mythology of spaghettification. Yes, you mentioned it. Of course, you have to. It's a it's a law of nature. Right? But you really get into the hard facts and and physics of it and it's no surprise because of your scientific training and your your past books as well. And speaking of books, I like to do what you're never supposed to do on the show, which is a feature called judging books by their cover. So I actually bought the audiobook and rated it with an asterism of five stars. Nothing less would suffice.

It's got the encomium, that it well deserves from Richard Dawkins, a pretty wonderful book. And from my, one of my kids' favorite astrophysicist, also named Brian, Brian May. Oh my god. It says, Marcus Marcus Chung rocks. Wow. You can't ask for a better so so, please, that's the back cover. But judge the front cover, title, subtitle, and this mysterious monstrous cover art that's so beautiful.

Glad you like it. But I I should point out that there are two types of black holes. There are theoretical black holes, which you you talk about, which are fantastically important because, you know, major theories of physics collide in black holes. Our theory of the microscopic role, quantum theory, our theory of big things, general relativity, and thermodynamics, our theory of heat. They clash, and they're not melded. They they predict different things, in the same domain, which is gold dust for physicists because when when a a a theory is shown to to break down and Einstein's theory of gravity breaks down in the center of a black hole, then we we are encouraged to look for a deeper, better theory. So there's there's there's theoretical black holes, and, of course, Stephen Hawking's name is associated with those. And then there's the real black holes, which are the black holes we've actually found out in the universe.