Super Cool

Summary

Radiolab Episode Summary: "Super Cool"

Podcast: Radiolab (WNYC Studios)
Original Air Date: December 5, 2017
Hosts: Jad Abumrad and Robert Krulwich
Special Guest: Walter Murch

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Episode Overview

In "Super Cool," Radiolab explores the science and mythology of supercooling—how water can remain liquid below its freezing point and then transform into ice instantaneously in the right conditions. The episode is sparked by a chilling wartime story involving horses and a lake that supposedly flash-froze around them. Through debates, experiments, and insights from scientists, the episode unpacks both the plausibility of the story and the underlying physics, before leaping into the ways these phenomena provide metaphors for the birth and structure of the universe itself.

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Key Discussion Points and Insights

1. The Story That Started It All: Horses Frozen in a Lake

• Walter Murch introduces a haunting tale purportedly from WWII: During the siege of Leningrad, Soviet horses, fleeing a forest fire, rush into a lake—which then instantly freezes around them, trapping their heads in a "sculpture garden" of ice.
  • “In the blink of an eye, the lake snaps them shut. It just freezes suddenly, turns to ice with a bang.” — Walter Murch [05:33]
  • Both hosts react to the story's power and strangeness—Jad is fascinated, Robert is skeptical.
• The group quickly moves to determine if this story could possibly be true or is merely metaphorical.

2. Investigating the Science: Supercooled Water and Nucleation

• The team visits Rockefeller University to try a supercooling experiment with Alexander Petrov.
  • Using ultra-pure water supercooled to -20°C, a plastic horse is dropped in, causing the water to freeze instantly.
    • “Because the moment that little plastic horse hit the water, the water slammed into ice.” — Jad Abumrad [09:46]
  • This dramatic demonstration shows catastrophic, near-instantaneous ice formation, but only in controlled conditions.

3. What Actually Makes Water Freeze?

• Virginia Walker, biologist, explains water's need for a "nucleator"—a seed particle (like dust or bacteria) that triggers freezing.
  • “The only reason that water freezes normally at 0°C is that there’s something there that makes it freeze. We call that a nucleator.” — Virginia Walker [10:33]
  • Without nucleators, water can be cooled far below freezing without solidifying—until something disturbs it.

4. How Plausible Is the Lake Story?

• Multiple experts, including glaciologist Erin Pettit, debunk the instant-lake-freeze premise for a real-world lake full of impurities and warm-blooded horses.
  • “When you’re talking about freezing an entire lake, you’ve got a lot of problems to consider… the water would never have been pure enough to supercool.” — Stephanie (paraphrasing Erin Pettit and Virginia Walker) [21:10]
  • Summary answer: The story is metaphorical at best, not possible under natural circumstances.

5. The Bacteria Connection: Microbes as Cloud Seeding Engineers

• Fascinatingly, certain bacteria serve as highly effective ice nucleators—helping water in the clouds form ice crystals, which become snowflakes.
  • “If you melt each snowflake, you’ll find a little bacterium inside it.” — Virginia Walker [20:01]
  • Bacteria’s evolutionary reason for this ability may be to hitch a ride to new places via snowflakes—turning winter weather into a method of transportation.

6. From Icy Lakes to Star-Birthing Clouds: The Cosmic Parallel

• The conversation shifts to how supercooling and nucleation provide a metaphor for the early universe.
  • Janna Levin, physicist, describes how tiny density fluctuations (“seeds”) in the young, rapidly cooling universe led to the large-scale structures—galaxies, clusters—that we see today.
  • “Amazingly, the largest structures that we know about in the universe have their seeds in these tiny fluctuations.” — Janna Levin [25:23]
• Jad notes that supercooling and seeding happen many times during cosmic evolution; perhaps more, as the universe continues to cool.

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Notable Quotes & Memorable Moments

• On the emotional power of the story:
  “You have hundreds of horses bolting through this flaming... heading towards the open space ahead, which was the lake.” — Walter Murch [05:12]
• On the scientific skepticism:
  “I told you at the time, don’t trust this story. It’s not scientifically possible.” — Robert Krulwich [07:16]
  • “Did somebody actually see this? What is the actual evidence?” — Stephanie [21:42]
• On discovering the bacterium at the heart of every snowflake:
  “If they make ice, they can get back down, and they can get back down in a different place and start a new colony of bacteria somewhere else. And so by this way, they get dispersed around the whole Earth.” — Virginia Walker [19:44]
• On the cosmic scale:
  “Like these beautiful structures that you’re describing are like the snowflakes around the little bit of D.” — Janna Levin [26:11]

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Timestamps for Important Segments

• Intro & Setup: [01:03-01:45]
• Malaparte’s Freezing Lake Story: [02:28-07:13]
• Experiment with Supercooled Water: [07:57-10:11]
• Explaining Nucleators & Ice Formation: [10:15-12:34]
• Key Science: Nucleators in Lakes and Bacteria: [17:17-20:09]
• Examining Story Authenticity, Scientific Rebuttal: [20:19-22:23]
• Cosmic Metaphor: Phase Transitions and Universe Formation: [22:26-27:13]
• Credits and Further Listening: [27:27-end]

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Summary Takeaway

Radiolab’s “Super Cool” is a masterful blend of storytelling and science: a haunting, possibly apocryphal wartime tale leads to a real laboratory demonstration of supercooling, a primer on nucleation (from dust to bacteria), and finally a grand cosmic metaphor explaining the birth and clustering of matter in the universe. The episode ultimately debunks the legend while marveling at the awe-inspiring phenomena that inspired it.

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Further Exploration:

• Watch videos of supercooling experiments at: Radiolab.org
• Read Walter Murch's translation of Malaparte's writings: The Bird that Swallowed Its Cage

Transcript

[Jad Abumrad]

Hey, Fidelity. How can I remember to invest every month?

[Stephanie]

With the Fidelity app, you can choose a schedule and set up recurring investments in stocks and ETFs. Huh.

[Jad Abumrad]

That sounds easier than I thought.

[Stephanie]

You got this?

[Jad Abumrad]

Yeah, I do. Now, where did I put my keys?

[Stephanie]

You will find them where you left them.

[Robert Krulwich]

Investing involves risk, including risk of loss.

[Walter Murch]

Fidelity Brokerage Services, llc. Member nyse, sipc.

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[Jad Abumrad]

Oh, wait, you're listening.

[Virginia Walker]

Okay. All right.

[Robert Krulwich]

Okay.

[Jad Abumrad]

All right. You're listening to Radiolab Radio from wnyc. Hey, I'm Jad Abumrad.

[Robert Krulwich]

I'm Robert Krulwich.

[Jad Abumrad]

This is Radiolab.

[Robert Krulwich]

And what we're going to do in this particular show is we're going to.

[Jad Abumrad]

This is one of my favorites. Yeah, favorite.

[Robert Krulwich]

It should be, because you certainly gave it your all.

[Jad Abumrad]

Exactly. I don't know. What do we need to say here? I mean, this is a little bit of a tussle. We sort of wanted to bring it back. Cause, you know, winter's approaching. Things are kind of heavy right now. We could use a little lightness.

[Robert Krulwich]

So this begins with a very, very successful film editor with. Well, you'll meet him in a moment. Comes to us with an idea, which Jad loves, I hate, and things go from there.

[Jad Abumrad]

Perfect. Can you hear us now?

[Robert Krulwich]

Hello?

[Jad Abumrad]

Hel.

[Robert Krulwich]

Hello.

[Jad Abumrad]

Hello.

[Robert Krulwich]

Hello.

[Jad Abumrad]

It starts with Walter, my hero, Walter Murch.

[Walter Murch]

I'm a film editor and sound designer, and I've been working in film since the late 1960s.

[Jad Abumrad]

Resume includes.

[Robert Krulwich]

I'm gonna make him an offer he can't refuse. The Godfather.

[Jad Abumrad]

Apocalypse Now. I love the smell of napalm in the morning. Ton of other films.

[Robert Krulwich]

The thing we're talking about in so youo Should Know is the.

[Jad Abumrad]

One of the more spectacular stories I've ever heard.

[Robert Krulwich]

How did you bump into this?

[Walter Murch]

Well, I was in Lyon in France, doing a film, Unbearable Lightness of Being.

[Jad Abumrad]

This is back in 1986.

[Walter Murch]

I was supposed to be there for a week, and it wound up I was there for a month and I ran out of things to read. So I went down the street from the hotel and there was a bookstore and I was interested, and still am, in cosmology. So I picked up a book by the Carl Sagan of France, a man named Hubert Reeves.

[Jad Abumrad]

Hubert Hubert, Actually, he's French Canadian.

[Robert Krulwich]

He translates as Carl Sagan.

[Jad Abumrad]

Anyway, Murch ends up buying Reeves book, goes back to the hotel, finds a cozy spot.

[Walter Murch]

So I was happily reading away and he was trying to explain, with some difficulty, because it's a difficult topic, how did matter condense out of the sort of cork soup that we believe happened right after the Big Bang? And he tried various attempts scientifically, but then he said, to give you a sense of the poetry of this moment, the best thing is the story that Malaparte tells.

[Robert Krulwich]

Who is Malaparte?

[Walter Murch]

Well, he was a journalist, a poet, diplomat, soldier, prisoner, film director, and somebody who got around. Yeah.

[Jad Abumrad]

And speaking of getting around, in 1942, a Milanese newspaper, Corriere della Serra, sent.

[Walter Murch]

Malaparte to report on the eastern and.

[Jad Abumrad]

Northern fronts of the war, specifically the Russian Finnish border.

[Walter Murch]

And he had a front row seat of the siege of Leningrad, the agony of the Nazi bombardment of that city.

[Robert Krulwich]

And it's from there that Malaparte tells his story.

[Walter Murch]

So this one day, this was in.

[Robert Krulwich]

The winter, Malaparty was posted with the Finnish army who were fighting along with the Nazis. And they were perched just north of.

[Walter Murch]

Leningrad on the shores of Lake Ladoga, which is this big lake abutting the city.

[Robert Krulwich]

And on this day.

[Walter Murch]

The Nazis bombarded area around the lake. This started a forest fire.

[Jad Abumrad]

Everyone ran for cover, soldiers ran every which way. And in the middle of the forest there were Soviet horses that were locked up in a stable.

[Walter Murch]

And the horses panicked and broke out of the stables, hundreds of them.

[Jad Abumrad]

And they just started running, rushing to.

[Robert Krulwich]

Get away from the fire, right?

[Jad Abumrad]

So you have hundreds of horses bolting.

[Walter Murch]

Through this flaming, heading towards the open space ahead, which was the lake.

[Jad Abumrad]

And all at once they burst out of the forest and go barreling into the lake, stampeding one on top of the other as they all get deeper.

[Walter Murch]

And deeper up to their heads.

[Jad Abumrad]

And it is at this moment when they enter the lake that according to the story, something very weird happens. In the blink of an eye, the.

[Walter Murch]

Lake snaps them shut. It just freezes suddenly, turns to ice with a bang.

[Jad Abumrad]

It goes from water to ice with this violent snap. And suddenly the horses are entombed. Malaparte writes that even the waves on the lake were gripped in midair and sort of suspended there.

[Walter Murch]

Fade out the next Morning, when Malaparte and the Finns were woke up, they discovered the forest fire had burned itself out. And look at that. The lake has frozen solid overnight. And his Finnish friends said, yes, that sometimes happens. And then they look and see, what are those bumps on the ice over there? They go to investigate and they find themselves in this horrific sculpture garden of horses heads sticking up out of this solid marble, like floor of ice.

[Jad Abumrad]

You said hundreds. So hundreds of horse heads.

[Walter Murch]

Hundreds of horse heads.

[Robert Krulwich]

These are not going to decay.

[Walter Murch]

Right.

[Robert Krulwich]

Because it's freezing cold.

[Walter Murch]

So those horses stayed there all winter. And Malaparte was there in that region of the world during that winter. And every so often, he and the other soldiers would go and have a smoke and they'd go into the sculpture garden and wander around looking at this miraculous thing.

[Jad Abumrad]

So this image of the horses frozen.

[Walter Murch]

In this lake, this image, beautiful and strange and disturbing and profound in some.

[Jad Abumrad]

Way, made us wonder what Made me wonder, I should say.

[Robert Krulwich]

I told you at the time, don't trust this story. It's not scientifically impossible.

[Jad Abumrad]

And I, keeping an open heart, you thought, could this possibly be true? Could there be a grain, perhaps several grains, Perhaps a lake's worth of grains of truth?

[Robert Krulwich]

Your heart, your mind is like loose, like a sieve. Anyway, we've argued about this for a year.

[Jad Abumrad]

Yeah. And you know what? We're gonna reconstruct that argument right now and take this uptown.

[Virginia Walker]

All right.

[Jad Abumrad]

Let's do this.

[Robert Krulwich]

To a real scientist.

[Jad Abumrad]

To a real scientist. In the course of our argument, we ended up going uptown to Rockefeller University to meet a couple people who know about ice. So we're going to go play with.

[Stephanie]

Some super cool ice.

[Jad Abumrad]

Among them, this fellow. I'm Alexander Petrov. I am the Raymond and Beverly Sackler fellow.

[Robert Krulwich]

Do you ever wonder who are Raymond and Beverly Sackler?

[Jad Abumrad]

They occasionally almost show up, and I almost meet them, but I never have. Yeah. By the way, the Sackler family has recently come into a bit of controversy. We all know that now, we didn't at the time. In any case, Alex, who, it must be said is an amazing dude, graciously agreed to demonstrate that you can, in fact, create the conditions of that massive lake inside a tiny little test tube. Okay, could somebody hold this sort of in here? And I'll get the tube set up. He reached inside his freezer, grabbed his trusty falcon. Yeah, this is called a Falcon tube. Just a plastic tube filled with water. Now, this is not normal water.

[Stephanie]

This is the really nice water.

[Jad Abumrad]

It's very, very pure water. No minerals, no dust. In there, like, super distilled. And. And he says when you take water like that and you cool it down, you can get it far below its freezing point and it won't freeze. Unless, that is, you happen to have a horse. You have a tiny horse here.

[Robert Krulwich]

We have a tiny horse, and we.

[Alexander Petrov]

Are gonna drop that into the Falcon.

[Jad Abumrad]

Tube and do that.

[Alexander Petrov]

That's gonna be awesome.

[Jad Abumrad]

So he handed us the tube. I'm holding a little vial of supercooled water. Alex, what temperature do you think this? -20. This is min. -20 c c Celsius.

[Robert Krulwich]

When does water freeze? In zero. So it's 20 degrees below freezing point, and it's still water.

[Jad Abumrad]

But not for long because we unscrewed the cap. Are you. Are you filming? We held the little plastic horse over the tube.

[Robert Krulwich]

Countdown or something.

[Jad Abumrad]

Okay, on the count of three. Guilty.

[Robert Krulwich]

All right, three. Oh, my God. Oh, my God.

[Jad Abumrad]

Point for Jad. Because the moment that little plastic horse hit the water, the water slammed into ice. I got excited. Suddenly, that little guy was trapped in an ice cube. Oh, my God. The horse is frozen.

[Walter Murch]

That's amazing.

[Robert Krulwich]

Please remember, the horse was plastic. No animals were harmed in this experiment.

[Jad Abumrad]

It is honestly breathtaking. Like, it happens so fast.

[Virginia Walker]

Catastrophic ice formation. Just like that.

[Jad Abumrad]

Did you hear that C word, Robert? Say it again. Catastrophic. This is Virginia Walker, and I'm in.

[Virginia Walker]

The Department of Biology, Queen's University.

[Jad Abumrad]

Virginia was one of the many people that we called up to ask, what the hell? Like, why does this happen? Shouldn't this water just freeze gradually the way that most water does? You know, at 32 degrees Fahrenheit or whatever?

[Virginia Walker]

No, actually. So you see, this is why we have to start at the beginning. As Julie Andrews says, a very good place to start. Right. All right, so the only reason that water freezes normally at 0 Celsius and 32 Fahrenheit is that there's something there that makes it freeze. We call that a nucleator.

[Jad Abumrad]

Sounds like a superhero.

[Virginia Walker]

Yeah. All right, so it's a nucleator.

[Jad Abumrad]

A nucleator is like a seed, right? Didn't know this, but it turns out water almost always needs a seed in order to grow ice.

[Stephanie]

It turns out water by itself is not actually that good at remembering how to become ice.

[Jad Abumrad]

That is Erin Pettit.

[Stephanie]

She's a glaciologist at the University of Alaska Fairbanks.

[Jad Abumrad]

And what she means is that when water cools down, the molecules start to slow their movement.

[Stephanie]

They get a little bit closer together.

[Jad Abumrad]

And at that point, they want to all hold hands. And become ice.

[Stephanie]

But the water molecules don't quite remember very well how they're supposed to be organized.

[Jad Abumrad]

They're like, wait, do you stand here? And I stand here? How do we do this?

[Stephanie]

Again, they need to be shown what combination of angles work the best to create a nice, stable structure.

[Jad Abumrad]

What they need is, say, a speck of dust. That's the nucleator. If you throw in some dust into otherwise pure water, now they have a.

[Stephanie]

Guide, because ice can start to mimic whatever the shape of the dust particle is.

[Jad Abumrad]

But what happens is that the water molecules start to form a cage around the dust particle, and that cage shape is very similar to the shape they need to make ice. And suddenly they're like, oh, that's how we do it. So in a sense, the dust particle is reminding the water molecules how to freeze.

[Virginia Walker]

Well, no, I don't think of it like that.

[Jad Abumrad]

Virginia says it's actually not quite so gentle, really. What's happening is the dust particle is forcing the water molecules into the right shape around it. It's like a command.

[Virginia Walker]

It's nothing about memory. It's a physical thing. They just get jammed in there.

[Robert Krulwich]

Wow, this is like Julie Andrews, like a Nazi. So then these start at the very beginning. Start at the very beginning.

[Jad Abumrad]

Okay, so if, as we just learned, water needs a catalyst, a nucleator, in order to freeze, doesn't this at least raise the possibility that that Finnish Russian lake had reached a supercooled state? Along come these horses, and they were the nucleators. Maybe they had dust on their hair or whatever. I don't know. Whatever it was, it started a chain reaction. Ice spread outward from these horses, shot across the entire lake, and froze the whole damn thing at once.

[Robert Krulwich]

If you'll excuse me for just a second, because this is like a touretting, like, impulse. I have. Excuse me. Now we can continue.

[Jad Abumrad]

Hold your horses there. We're going to take a break, and we'll continue this meaningless tussle in just a moment.

[Stephanie]

This is Alicia Bridges calling from Saskatoon in Saskatchewan. Radiolab is supported in part by the Alfred P. Sloan foundation, enhancing public understanding of science and technology in the modern world. More information about [e-mail]. radiolab is supported by BILT. Nobody wants to pay rent, but if you have to, BILT works to make it more worthwhile. By paying rent through bilt, you can earn flexible points that can be redeemed toward hundreds of hotels and airlines, a future rent payment, your next lift ride, and more. But it doesn't stop there. You can Dine out at your favorite local restaurants and earn additional points. Get VIP treatment at certain fitness studios and enjoy exclusive, exclusive experiences just for built members. Every month earn points on rent and around your neighborhood, wherever you call home by going to joinbuilt.com Radiolab that's J-O-I-N-B-I-L-T.com Radiolab.

[Alexander Petrov]

Radiolab is supported by Rippling Finance. Teams often spend weeks chasing receipts, reconciling spreadsheets and fixing errors across disconnected spend tools. This can be frustrating, and that's not software as a service, that's sad software as a disservice. If you've been thinking about replacing stitched together tech stacks with one platform for all departments, Rippling can help. Rippling is a unified platform for global hr, payroll, IT and finance, helping people replace their mess of cobbled together tools with one system designed to help give leaders clarity, speed and control. By uniting employees, teams and departments in one system, Rippling works to remove the bottlenecks, busy work and silos in business software. With Rippling you can choose to run hr, IT and finance operations as one, or pick and choose the products that best fill the gaps. Right now you can get 6 months free when you go to rippling.com Radiolab learn more at r-ip p l-I n g.com Radiolab terms and conditions apply. Radiolab is supported by Planet Visionaries, the podcast created in partnership with the Rolex Perpetual Planet Initiative. Stay tuned for a trailer and subscribe wherever you get your podcasts.

[Walter Murch]

I'm Alex Honl, professional rock climber and.

[Janna Levin]

Founder of the Honl Foundation.

[Jad Abumrad]

I wanted to let you know about a brand new season of the Planet.

[Walter Murch]

Visionaries podcast in partnership with the Rolex Perpetual Planet Initiative. This is the podcast exploring bold ideas.

[Jad Abumrad]

And big solutions from the people leading.

[Walter Murch]

The way in conservation. Join me in conversation with the likes of climate champion Mark Ruffalo, biologist and photographer Christina Mittermeier, and one of the most successful conservationists of our time, Chris Tompkins. Join us on Planet Visionaries wherever you get your podcasts.

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[Jad Abumrad]

Okay, so, Jad, Robert, Radiolab. Before the break, we posited what I thought was an interesting theory. Robert, not buying it. We'll get to your skepticism in a moment, but I want to talk a little bit more about nucleators for a second, because when we were talking with Virginia, she told us something kind of cool. We asked her, like, what else nucleates ice? Like, we learned about dust, but what else can do it?

[Virginia Walker]

Okay, so the best nucle is ice itself.

[Jad Abumrad]

She says if a little bit of snow falls into some water or a little bit of ice forms in the water organically, the water molecules will rush around that, and bam.

[Virginia Walker]

If you don't have ice, what is the second best thing to nucleate? This ice happens to be bacteria.

[Jad Abumrad]

Turns out, she Sundays, there are three different kinds of bacteria that can generate these special proteins, big honking proteins that can instantly turn water into ice.

[Robert Krulwich]

In fact, when we were reporting this story, a video started circulating on the Internet that showed a scientist taking a bottle of water, squirting a little bit of this bacteria in, and then the thing just shocked into ice.

[Virginia Walker]

And the cool thing is these bacteria are actually plant pathogens, plant killers. So you've probably seen grass growing in your backyard or whatever, and it can be all covered with frost, but then, you know, the frost can melt, and it's still green. Yeah, but if those bacteria are present.

[Jad Abumrad]

She says, they'll spit out their proteins onto the plant, which generates these ice crystals. The ice crystals then slice the plant.

[Virginia Walker]

Open and expose the inside of the plant. And the bacteria say, mmm, yummy. Here's lunch. And they eat the inside of the plant.

[Jad Abumrad]

It's a good strategy, but that's not the cool part. Virginia says she has also found these proteins in bacteria that don't kill plants. So that made me think, made her wonder why, like, why would they need to make ice? And that's when it occurred to her and a few other researchers, maybe it's about transportation.

[Virginia Walker]

Exactly.

[Robert Krulwich]

What?

[Jad Abumrad]

Well, think about it. These bacteria are just sitting on these.

[Virginia Walker]

Plants, and what happens is the wind comes along, blows up these little bacteria.

[Jad Abumrad]

Into the upper atmosphere, blows them literally up into the clouds.

[Virginia Walker]

They're not particularly cold, hardy, so now.

[Jad Abumrad]

They have a situation. They do not want to be all the way up there.

[Virginia Walker]

They gotta get back down to the earth. And unless they hitch a ride on those horses that you keep talking about, they're so light, they might not come down to Earth.

[Jad Abumrad]

So what they do, she suspects, is they use the plant trick. They spit out these proteins into the cold, wet cloud which galvanizes the water molecules around them to form. A snowflake around their body. So now they've got this little hovercraft that they can use to coast on down.

[Virginia Walker]

If they make ice, they can get back down, and they can get back down in a different place and start a new colony of bacteria somewhere else. And so by this way, they get dispersed around the whole Earth.

[Jad Abumrad]

Think about that the next time it's winter and it snows.

[Virginia Walker]

Apparently, if you melt each snowflake, you'll find a little bacterium inside it.

[Jad Abumrad]

You're saying all of them?

[Virginia Walker]

All the snowflakes? I haven't looked at every single snowflake, of course, but it makes perfect sense, doesn't it?

[Jad Abumrad]

But that's a very, very cool idea.

[Virginia Walker]

Yeah.

[Jad Abumrad]

I suddenly like the bacteria movie a hell of a lot better than the horse movie. So at least I, you know, and it at least has a shot of being, Yeah, the horses. So when we were reporting this story and talking to Aaron Pettit and Virginia Walker and a bunch of other scientists, when we asked them, could an entire lake have flash frozen in an instant, trapping all those horses uniformly, the answer that we got was no.

[Robert Krulwich]

Did you hear her? No there. Did you hear the sound of it? It seemed somewhat summery. Let me ask it to a different way. Would you say absolutely not, or is it just a kind of a gentle no?

[Stephanie]

I'd say that's an absolutely not.

[Virginia Walker]

Okay.

[Robert Krulwich]

Because as Aaron told us, when you're talking about freezing an entire lake, well, you've got a lot of problems to consider.

[Stephanie]

First, the process of freezing actually is a source of heat itself, because like.

[Robert Krulwich]

When water molecules form bonds to make ice, that's a lot of activity, and activity produces energy. And now that's gonna make things a little bit warmer. Not to mention the fact that horses are warm blooded animals, so they also would slow down the process of freezing.

[Virginia Walker]

Right.

[Robert Krulwich]

Also, the water would never have been pure enough to supercool in the first.

[Stephanie]

Place because there's too many things in the lake that would provide that initial nucleation. Plants, organisms, dirt.

[Jad Abumrad]

Damn it.

[Stephanie]

Did somebody actually see this? What is the actual evidence that.

[Walter Murch]

No, nobody saw any of this as it actually happened.

[Jad Abumrad]

When we told Walter Murch what the scientists told us, in typical Walter Murch fashion, he was icy, calm. And he reminded us that he never told us it was true. That Malaparte often mixed fact and fiction, and that the real reason he was attracted to this story was because it offered a metaphor for cosmology, right?

[Walter Murch]

The beginning of the universe, really.

[Robert Krulwich]

I mean, if you'll excuse me, if a small bit of skepticism. Now Walter thinks it's true for the universe.

[Jad Abumrad]

Metaphor. Metaphor.

[Robert Krulwich]

Even so. Even so.

[Virginia Walker]

Come on.

[Robert Krulwich]

What does he mean? What does he mean?

[Jad Abumrad]

Here's what he means. And if you're a physicist listening right now, just turn off the radio.

[Robert Krulwich]

We're just talking among ourselves here, right?

[Jad Abumrad]

So you can think of it in one of two ways, right? The first is that idea of super cooling that we saw at Rockefeller, where under the right circumstances, water can cool down way below its freezing point, not freeze, and then all of a sudden, And it can suddenly do that, which we saw at Rockefeller in the test tube. Now, according to Janna Levin, professor of.

[Janna Levin]

Physics and astronomy, Barnard College, Columbia University.

[Jad Abumrad]

The metaphor holds because that bizarro flash freezing phenomenon actually happened repeatedly, she says, in the moment after the Big bang.

[Janna Levin]

Yes, super cooling is definitely something that happens in the early universe.

[Jad Abumrad]

She says, right? When the universe got its start, it was still small, like the size of a grapefruit. Inside that grapefruit, it was extremely hot.

[Janna Levin]

Back then, it was probably a million trillion, trillion, trillion times hotter.

[Robert Krulwich]

A million trillion, trillion trillion times 10.

[Janna Levin]

To the 32 times hotter.

[Jad Abumrad]

But as a little grapefruit began to expand, the temperature started to drop, and it dropped and dropped to a point where the universe should freeze, so to speak. But it didn't. And it's waiting and it's waiting to freeze. And you're like, what's happening? Why aren't you freezing? Then suddenly, there it goes. Phase change.

[Robert Krulwich]

Go ahead.

[Jad Abumrad]

Okay.

[Robert Krulwich]

I don't know exactly what you're saying, but keep going.

[Jad Abumrad]

All I'm saying is there's a lot of phase changes. Some of them were super cool. Don't worry about it. Okay. There's another parallel which I think is actually even more interesting, has to do with those seeds we talked about. So if you go back to the grapefruit, okay, inside, it's very, very hot. You've got this wash of energy. And this energy is uniform, right? It's all the same thing, spread evenly everywhere, the same. But then as things cool, you begin.

[Janna Levin]

To get these tiny fluctuations, little variations.

[Jad Abumrad]

In temperature and density where it's a.

[Janna Levin]

Little bit hotter and denser in one point than another.

[Jad Abumrad]

We're talking about clumps. Like maybe over here, there's a little bit more matter and heat than over there. And these are our seeds, see?

[Robert Krulwich]

I Don't think that you're describing seeds like I understand seeds. Seeds are little things that attract other stuff.

[Jad Abumrad]

No, no, but these behave just like seeds. Because as the universe cools down and expands and begins to add all these new forces and all these new particles, gravity, electron photons, atoms, those little bits of variation from the beginning are still there, and now they're growing bigger because now we have gravity, right? So little concentrations of stuff are now attracting more stuff and then more stuff and then more stuff. And as the universe expands, they expand until ultimately those little brightness have become these massive objects.

[Janna Levin]

Amazingly, the largest structures that we know about in the universe have their seeds in these tiny fluctuations.

[Robert Krulwich]

Does that mean when you go on a Star wars kind of voyage, so you're in your spaceship and you're going at some incredibly high speed, you're rushing through the universe and you see huge clouds of gas with nurseries for stars, and you leave them and you go to a galaxy and then another galaxy. There's a galaxy over and a galaxy over there and a galaxy over here. You're saying that these massive structures, walls of galaxies, neighborhoods of stars, are reflections of a very early moment when something went in the initial broil of stuff.

[Janna Levin]

Like these beautiful structures that you're describing are like the snowflakes around the little bit of D.

[Robert Krulwich]

So does that mean that the empty spaces that we see when we gaze at the current universe are actually filled with something that hasn't cooled yet or that isn't visible to us or is working under a different rule?

[Janna Levin]

Well, if I can hijack your question, I can say we might not have seen the last of the phase transitions. Our universe is absolutely continuing to cool.

[Jad Abumrad]

Is it really? Yeah, it's cooling down.

[Janna Levin]

It's very cold right now. We have this dark energy driving the universe to expand at an ever accelerated rate. And it's conceivable that in the future that energy will endure some phase transition and it will go away or decay to something else. In this new state of matter, it might do something different to the evolution of the universe. So we might have a phase transition in our future.

[Robert Krulwich]

Suddenly, I feel a little. Oh, dear.

[Jad Abumrad]

Hello.

[Robert Krulwich]

We have many people to thank who helped us on this particular podcast.

[Jad Abumrad]

Totally. Producers Matthew Kielty, Molly Webster. Woo. Also Amanda Aranchak, Atish Batya, for sure.

[Robert Krulwich]

And Marine Budeau.

[Jad Abumrad]

These super cool people at Rockefeller University. Jeannie Garberino, Philip Kidd, and of course, Alexander Petrov. Thanks also to Jeffersonstrom, Inger Herberg, Mark.

[Robert Krulwich]

Martin, Martin Truffer, Mark Tuckerman, and Jason Wexler. And sincere thanks to all the listeners from Facebook and Twitter who helped us translate Russian and Finnish books.

[Jad Abumrad]

Oh, and certainly last but not least, Walter Murch for being my hero.

[Robert Krulwich]

Chad loves you.

[Jad Abumrad]

I love you. And more importantly, he released a book translating Malaparte from Italian to English, which is where we got the story of the. Of the horses falling in the lake. It's called the Bird that Swallowed Its Cage. The Selected Writings of Curzio Malaparte.

[Robert Krulwich]

All right, so that's, that's us saying.

[Jad Abumrad]

Oh, wait, one more thing, one more thing. Go to our website, Radiolab.org and you can see videos we shot at Rockefeller of water turning into ice in a flash, super cooling, right in front of your eyes. It's amazing. Radiolab.org, i'm Jad Abumrad.

[Robert Krulwich]

I'm Robert Crowart.

[Jad Abumrad]

Thanks for listening.

[Stephanie]

This is Stephanie calling from Bushwick, Brooklyn. Radiolab was created by Jad Abumrad and is produced by Soren Wheeler. Dylan Keefe is our director of sound design. Maria Matassar Padilla is our managing director. Our staff includes Simon Adler, Becca Bressler, Rachel Cusick, David Gabelle, Bethel Hapti, Tracy Hunt, Matt Kielty, Robert Crowwich, Annie McKeown, Latif Nasser, Melissa O', Donnell, Arianne Wack, Pat Walters, and Molly Webster, with help from Amanda Arancik, Shima Oliay, David Fuchs, Nigar Fatali, Phoebe Wang, and Katie Ferguson. Our fact checker is Michelle Harris.