Little Black Holes Everywhere

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Radiolab from WNYC See Yep.

I'm Lulu Miller.

And this is Radiolab.

And today we have two very different stories from two very different reporters, one of whom is you, Molly.

Yeah.

Who each got pulled down into the same very strange and very dark place.

All right, okay, thank you for joining me.

And we're going to begin with producer Annie McKeown.

Yeah, yeah, yeah.

Well, where do you want to start?

Where do I want to start? I want to start in Siberia.

Okay.

Okay, so the year is 1908, it is June, it is a bright, sunny morning.

Whoa?

It arcs across the sky, disappearing over the horizon.

Huh, wow.

And, uh, I don't know, have either of you heard of this before? It's called the Tunguska Event, No.

I've never heard of it.

Tunguska, Tunguska, that's the town.

That's the nearby river, okay? And today, this is still considered the largest impact event in recorded human history, so like an impact....

So there's a something that, like, hit us.

Yes, well, maybe.

Hmm.

Okay.

So a bunch of scientists go plunging into the forest to try to figure out what the heck just happened. They scramble over fallen log after fallen log, through dense bog after dense bog for miles, until finally they realize....

Uh, really.

Yeah, they can't find any evidence of what caused this huge explosion.

Wait, what?

Like, they sort of figured this must have been an asteroid, so they thought they'd find debris from an asteroid. Like space Rock. Yeah, they don't find a single bit of space rock in this whole area, weird.

That's kind of spooky.

In 800 square miles of destruction, there was like nothing from space.

Yeah.

Not even a hole. This is why people think UFOs exist.

Yeah, and I think that, like, that's what the scientists were like. Well, we have to find what obviously should be there. And so all kinds of ideas cropped up, like some people thought it was. Maybe like a natural gas bubble that bursts from beneath Earth's crust, but that doesn't explain, like the bright light in the sky.

It's like an office building, yeah, or like an apartment building headed toward planet Earth.

Right, and the theory is that it came into Earth's atmosphere at kind of a weird angle.

Wait, but then are there some chunks, or it's just dust and fire and energy?

That's the thing, like, that's a real question, like, shouldn't there be some pieces of this like somewhere out there, like some sort of evidence, yeah.

That does seem strange, doesn't it?

I think it does, yeah.

But, you know, it's pretty plausibly an atmospheric explosion, and I think, you know, most scientists have sort of dusted their hands off. And moved on to the next question with regards to Tunguska.

It's not a cold case. It's not like, Oh, on the shelf, isn't it?

Well, I think in some people's minds it is, some still believe it wasn't an asteroid.

This is astrophysicist Matt O'Dowd.

Professor at the City University of New York, Lehman College.

And I reached out to Matt because I had recently seen him on his side gig.

Have you ever asked what is beyond the edge of the universe?

This really awesome physics YouTube show.

What would it take to build a starship, which is called PBS Space Time?

Talking about this really wild.

Absolutely.

Alternate theory of what could have caused the Tunguska event of 1908.

Which is the black hole?

Wait.

That's.

Wait, like a black hole, like a space black hole. Did this, like how I don't know, radiated a death wave toward planet Earth.

No, what, Matt's talking about a black hole actually hitting Earth.

Exactly What?

Which sounds impossible, because usually, when we're talking black holes, my God, right out of Dante's inferno. We're talking about these big, terrifying, churning places in space where gravity is just so strong that not even light can escape it.

Like, they warp the space around them, change the flow of time and all of that awesome stuff that comes out of general relativity.

But if one of these black holes approached Earth, its gravitational pull would be so strong that.

Earth would be, they call it spaghettified, the black hole would pull Earth in.

The entire planet would begin to stretch towards the black hole. And then, as it punched in,....

Earth would essentially follow it through the hole that it made, what you can imagine Earth just folding in afterwards, and it would probably follow the black hole in this stream of super hot stuff.

Until all of earth, everything on it, everything in it is ripped apart into individual atoms, and Earth is devoured.

That's so awesome, it's awesome.

Not what happened.

But you would also notice.

Right, right, right.

We would all agree today, exactly.

That was a black hole, exactly right?

Okay, so this obviously is not a very plausible explanation for the Tunguska event. No, no.

Certainly not.

But that's because there's one very important difference between these black holes and the one that potentially destroyed 800 square miles of Siberian forest. Which is that, rather than being this giant monster, the Tunguska black hole would have been a really, really teeny tiny monster.

Very small.

Wait, black holes can be little.

Yeah, like, really small.

Like, how small?

Like, very tiny.

Itty Bitty.

So small.

I mean, could it fit on my hand?

Yeah, I mean.

Are we talking like a peanut?

We're talking like the size of a hydrogen atom.

Oh, an atom, yeah.

Oh my goodness, that is very small for a black hole.

So these tiny little black holes are special black holes, because typically a black hole gets made after a star explodes.

Yeah.

But these tiny little black holes, they got made in this one particular explosion.

13.

Which was a very great day for existence.

Yeah, exactly, awesome.

But a very upsetting day for Gravity.

Because, like the Big Bang, was the explosion outward, where things became free of gravity in a way.

And packed together in this really tight, dense ball, and then this little dense ball. Was this rapidly expanding ocean of hot hydrogen and helium, these bright, swirling gases, glowing and gravity? Was like, Oh my God, I have to get all this back in that tiny little hole again.

Exactly for one minute, I fell asleep, seriously.

So gravity is stressed.

Gravity is stressed and immediately begins.

To turn the whole universe into a black hole.

Trying to grab everything and pull it back together, which is not possible.

Mostly, it fails, you know, happily.

Because the expansion of the Big Bang is just too powerful, but everything is still.

So hot and so dense, and so compacted together.

That gravity is able to grab some of this stuff, crush it together to create.

What we call primordial black holes.

Black holes from the beginning of time.

Exactly.

Primordial black holes or PBHs, which do you prefer?

PBHS really? No, No, yeah, PBH, it sounds like PBS.

It sounds like a condiment.

Yeah, exactly, PBH sauce. Primordial Black Hole is good, it's really good, I'm happy to go with Primordial Black Hole.

I just didn't know if it was too much every time, but no, it was good.

I'll try to say it fast.

Great Matt explained that even though these primordial black holes could be as small as an atom.

Very massive.

There is still a huge amount of stuff packed into that small space, so it's an atom, but with the mass of.

An asteroid, basically.

Oh.

And the other thing is that super big black holes, they usually sit in the middle of a galaxy, with everything spinning around them, these little primordial black holes. They're kind of like untethered. And since everything in the universe is swirling and spinning and moving around.

Exactly.

And it's possible, or so the theory goes, that on a beautiful June morning in 1908. One of these primordial black holes. A particularly small one, about the size of a hydrogen atom, but with a mass equal to an office building-sized rock. Zooming along at 62 miles a second, about to make a direct hit with a certain patch of Siberian forest.

Okay.

We're back.

We're back. You ready for impact?

Oh my God, yeah.

All right, let's do it, mm-hmm.

Okay, now, now okay, all right. So this primordial black hole punches through the atmosphere.

Like a tiny needle of gravity.

And stuff gets pulled towards that gravitational field.

Stuff like nitrogen molecules, carbon dioxide.

Oxygen molecules.

And this tiny little black hole begins to eat it, devours molecule after molecule after molecule, and each one of those molecules.

As it fell into the black hole.

Becomes hotter than the surface of a star radiating.

An enormous amount of heat and energy.

And with all that energy around the black hole, this halo begins to form, and it's not very big, but it is shining.

Oh my god.

In that moment, if you'd been standing in the Siberian forest, looking up at the sky, this would have looked exactly like a second sun rocketing through the sky, pulling behind it a tail of blue and white light.

To be equivalent in energy to an asteroid exploding.

Which meant this tiny, primordial black hole was creating these enormous.

Shockwaves.

And what did that sound like?

I imagine a ginormous kaboom cool that would flatten this forest.

Knock people over, throw boats out of rivers, shatter windows.

And then it would hit the ground and it should actually leave a crater, oh.

But this one would be much smaller.

Sort of a column.

Probably not what the scientists have been looking for.

And it would have been harder to find.

It would also be very deep, because while an asteroid stops when it hits the Earth, the black hole doesn't even slow down what and as it plummets through the Earth.

Through its whole passage.

It would be generating these seismic waves.

These rings of earthquake expanding from around this bullet, shooting through the earth and the earthquakes wouldn't be strong, but they would be global.

Meaning every single person plant animal on Earth.

What, what?

The heck.

Is that a little earthquake? Hmm, hmm.

Anyway.

And some stuff does follow the black hole, but some stuff just gets super hot.

Leaving behind this trail, that.

It would at first be molten, and then it would solidify into this column of solid glass.

Like a glass lightsaber all the way through Earth, yes.

Yeah.

Stop it.

This long tunnel of altered material.

Wow.

And then it comes out somewhere.

And then, yeah, there would have to be an exit wound.

Wait, where would the exit wound be?

Well, it depends on what angle it came in at the angle.

Back in 1908, it could have easily been in the ocean somewhere, and we probably wouldn't have noticed.

If you're on a boat or standing nearby, would you be like, Oh my goodness? That was something that came up through the floor of the planet and it made a boom. And then there was a bright light.

It would be like a shooting star coming out of the ground.

That whole journey through the Earth would have taken this little black hole about two minutes, and then it would continue on making its way through the universe.

And as it goes forward on the rest of its journey, is there a little bit of 1908 forest floor Siberia inside it?

In some very altered form, yeah.

But okay, I am wondering, like, how many people think, or how likely is it that this is what happened, or is this like a pretty thought exercise?

Well, this is kind of a pretty thought exercise, but it doesn't mean that it's never happened or it's never going to happen. Tunguska just gives you kind of like a case study for like, Okay, well, is it possible that it could have been? And the scientists found out, Yes, it is possible. And statistically, something like this either has happened in Earth's history or truly might happen in Earth's future.

Well, now that we know there are little black holes out there, everywhere.

Who's going to tell him that the job he's currently seeking might just be one of those Black jobs?

Democrats depart from the high road at the DNC with some creative jabs at the Republican candidate.

That's what mockery does. It kind of shows you that that great and powerful Oz is merely a little man behind a curtain.

Examining the DEMs new lexicon on this week's On the Media from WNYC, Find on the Media wherever you get your podcasts.

Lulu Molly Radiolab B-holes, Black Holes.

So this next one comes to us from you, Molly.

Indeed.

So what do you got?

So when Annie came to our pitch meeting and she was like, Have I got a story for you guys?

It's like a star goes in.

A star goes in, we don't know, and you don't know, like, did the star get crushed? is the star through a wormhole out somewhere else? Did the star burn up?

Oh, interesting, so wait. So it's like the particles would come out and they might have little clues about, like the interiority of a black hole.

Yeah, they would be like, Hey, I'm a particle, and I'm telling you that there is a brown rock in here. Like, it would give you a hint of what the black hole has gobbled, or what the black hole has seen or intersected with. Okay, and the thought is that all of these particles that are shot out of the black hole kind of gather on its surface and create a glow.

Indeed, you did. I have it right here in front of me.

Yay.

It is called little black hole. Will you flip to the first page of the story and just read us the first couple pages of the story, okay?

There once was a little black hole who loved everything in the universe the stars, the planets, the space rocks and the space Fox, even the flying astronauts.

We all eat our friends.

And then the little black hole meets a big black hole, another black hole, and the big black hole tells the little black hole. To take a deep breath. And to close her eyes, and to think about the things she loves and what the little black hole sees is essentially, she sees herself glowing, she sees her hawking radiation, huh?

Oh.

Yeah.

I know that this is based on, like, rigorous astrophysics. But the journey that this little Black hole character is on, it does ring so true for loss in life. Like when friends disappear, when people go away, when you look up blinking and no one's left. That's a hard feeling that I think everybody, and kids for sure, but everybody like, has. But I authentically, like, really, really just loved the realization that, like the memories, the almost companionship in your mind. Like it doesn't have to go, it can.

It's interesting that you say that because I had a lot of trouble with the ending. Because I was like, I don't in any way want to imply to kids that. Just because you realize you have some memories inside of you, like, the world's a lot better, yeah, like, it's a little bit better, yeah.

Oh, I've got something for you. Oh, whoa, hi.

Hey Annie, hello, where did you come from?

Oh, I've actually, I actually never left, I've just quietly been here.

Okay, cool.

Anyway, so the reason I'm butting in is because of something that Matt told me.

So these are maybe my current favorite thing.

As we were wrapping up our interview.

Okay, so.

We've been talking about hawking radiation, black holes, evaporating all that good stuff. But then he told me about some current thinking.

There is one theory a number of very reasonable scientists think that, once, the black hole is very small.

Like when it evaporates basically all of itself away and is now.

The Planck scale.

Which is so impossibly teeny tiny that a rough way of understanding it is. If the Earth was the size of an atom, then one of these small things, these planck units, would be smaller than an atom on that atom sized Earth. Whoa, and when the black hole has evaporated down to this inconceivably tiny size?

There is no transition that lets it give up its last little bit of mass.

Oh, whoa. So that means that it can't die, that it just won't. If that's true, then there are kajillions of skeletons of black holes all over the universe.

Yes, what? And the wildest part of all this is that there is this mystery in the universe. You may have heard of the question of dark matter.

Oh yeah, yes. So that's the idea that there's 80 of matter in the universe that we don't know what it is. But it is heavy, dark and impossible to detect.

Right, and the theory goes that if black holes actually can't totally disappear, but instead get locked at that last teeny tiny, invisible size.

That sounds exactly like dark matter.

Perfect.

Exactly.

Perfect, and Matt says, If that's the case.

Then there must be an unthinkably large number of them out there, and in fact, they must be passing through the Earth constantly. If that's the case, really, I mean, there probably aren't any in the room with you right now.

Kill you.

Pass straight through your body and what would happen? And they are so small, you know, it would leave absolutely no sign.

Would you be like, how? no?

No, I don't think so, I'm sorry.

You wouldn't be like, Oh.

I mean, the thing is, atoms are mostly empty space, so they would zip between your electrons. OK, and I'm pretty sure even if they passed through the nucleus, they would just pass through the nucleus like it's empty space. I think they would need to have like a head on with a quark or something.

Then you may be like, Ow.

Yeah, and even well, yeah, no, I'm kidding ah.

Exactly, it's like this trail of stuff it would be pulling behind it.

Yeah, exactly, and that would be essentially what happens to most of the stuff. Because, yeah, because it's so small, the amount that it actually has a direct contact with would be.

Like it could only eat so much, it could eat so much.

And it only, you know, it's only whatever.

This episode was reported by Annie McKeown and Molly Webster.

It was produced by Annie McKeown and Becca Bressler, with help from Matt Kilty, fact-checked by Diane Kelly and edited by Alex Neeson.

Sound design by Matt Kilty and Annie McKeown, Jeremy Bloom mixing by Jeremy Bloom and dialogue mix by Arianne Wack. Special thanks to Matt Kaplan, a physicist at Illinois State University who worked on a team whose recent paper taught us what the impact crater left behind by a primordial black hole would actually look like.

We also want to thank Priyampadam Natarajan and Brian Green, and we dedicate this episode to our newest, favoritest, littlest, black hole, Annie McKeown's baby boy.

And then, finally, a reminder that Molly's children's book is now out everywhere.

I do, I do always. Did you know? Most black holes generally have a best friend?

Who?

A star.

Wait, what do you mean? That's just like, always nearby, like, what's his name? Flounder and the Little Mermaid.

Exactly exactly.

Wait, in what way? For real?

The star orbits the black hole, sort of floating in space together. And then, depending on how close they are, they may eat it all.

At some point, my jaw is so wide right now, I never knew that.

They may just, you know, grab up little bits of it and hug it pretty close.

That is wonderful, I am so happy to know that.

All right, well, thanks so much for listening. Enjoy all the little black holes hitting. You see you soon bye.

Radio Lab was created by Jad Abumrad and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co-hosts. Dylan Keefe is our director of sound design.

Our staff includes Simon Adler, Jeremy Bloom, Becca Bressler, Rachel Cusick, Akedi Foster-Keyes.

W. Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindhu, Niana Sambandang, Matt Kielty.

Annie McEwen, Alex Neeson, Sarah Kari, Ana Vazquez, Sarah Sandbach, Arianne Wack, Pat Walters and Molly Webster. With help from Sacha Kidajima-Molke. Our fact-checkers are Diane Kelly, Emily Krieger and Natalie Middleton.

Hi, my name is Michael Smith, I'm calling from Pennington, New Jersey. Leadership support for Radio Lab's science programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, Simon's Foundation initiative, and the John Templeton Foundation. Foundational support for Radio Lab was provided by the Alfred P. Sloan Foundation.