Happy holidays friends. This year, December twenty fifth marks both the start of Hanukkah and Christmas Day. Feeling in the festive spirit, Daniel and I decided to dig into some of the science behind these holiday stories. To the parents with kids who will be staying up late waiting for Santa this year, you may want to consider whether your children's holiday experience would be enhanced or diminished by putting
these magical stories under a scientific lens. So today we'll be asking ourselves questions like how does Santa manage to go fast enough to deliver toys to all the Christian kids in the world in just one night? And how does Rudolph produce that light to guide the way? Does he have a bad bacterial infection? And how does time dilation perhaps account for the Hanukkah oil burning for eight long days and nights. Welcome to Daniel and Kelly's extraordinarily festive universe.
Hi. I'm Daniel. I'm a particle physicist, and I think we don't have enough science holidays.
Ooh, I'm Kelly Wienersmith. I study parasites, and yeah, I'll back that up. My people. The ecologists are pretty excited about birthday. But you know, we could always use more holidays. What holiday would you.
Start Universe Day?
Nice? Yeah, I guess Earth Day would be a subset of Universe Day.
Mm hmmm, yeah, it encompasses everything. Why isn't everyday Universe Day? I'm looking forward to those ads already.
That's right. Well, how would you celebrate Universe Day?
That's a good question. You'd need a really dark chocolate cake, I guess, to represent the absolute mysteries of the universe and the impenetrable darkness of space.
I think if someone told me they were giving me a cake that represented the mysteries of the universe, I would be really worrying about what was inside that cake. Like, here's a razor blade. I don't know that I'd be excited about that cake.
I'm only putting razor blades and cakes I send to my friends in prison. Kelly, You're not in prison.
Not yet. No. I think we've established that the worst I've ever done is like jaywalked.
That's right.
Oh, no, we both committed dairy related crimes.
Mmmm yes, international cheese smuggling and butter smuggling.
Yeah. Yeah, man, we're rebels.
Maybe not a great idea, to admit to that on air.
There's a show I listened to and their slogan is like, don't instagram your crimes, and we're podcasting are crimes anyway, We're not the smartest criminals.
No. And the cheese was delicious, so probably worth it anyway.
Yeah, and the butter was delicious also.
And food is asential element for how people celebrate their holidays. That's why I think it should be the center of Universe Day, which I'm totally going to launch next year. But today on the podcast, we're not talking about fictitious holidays that we are starting to poke fun at real holidays. We're talking about the science of your holidays.
And I am so excited. You know. We are, of course recording this a bit in advance of December twenty fifth, and my family's putting up our Christmas tree this weekend and I am so excited. I love doing that with my daughter. She's always like super excited about it.
So does that mean that you observe the Christmas tree before Thanksgiving tradition?
We observe no traditions in particular. It's just whenever we remember like, oh we can do that now, And this just happens to be when we're all going to have time. So we're probably gonna do it on Thanksgiving Day, just because it's a time when we're all together.
And do you guys follow your childhood Christmas traditions because Zach grew up in a Jewish family.
No, We've created our own traditions that mesh together Honkkah and Christmas and work for our family. What about you? Are you doing what your family did? Is Katrina's family also did they celebrate Hankah.
Katrina's family is Danish, so they celebrated a very secular kind of Christmas, but with particular traditions involving like harrying and very thick bread and dinners that are called lunches and lots of schnaps and stuff like that, which is a lot of fun. And over the years we've invited like eighty people over to serve them this traditional Danish dinner which they call Christmas lunch, which is a lot
of fun. But I didn't grow up with any Christmas traditions because my family is Jewish, so our Christmas traditions are Katrina's Christmas traditions. Plus Hazel's social media desires from what she's seen on other people's TikTok. She's like, I want Christmas like that, so we, for example, all wear matching pajamas on Christmas morning.
I have tried to get Zach to do that, and he absolutely refuses, but I think it would be so cute. Oh that's great.
This year even the dog is getting magic pajamas.
Oh that's amazing. Do you send out like holiday cards afterwards or like New Year cards? Mostly? I just have to see this, all right, I'll put up a picture. Okay, awesome, I can't wait. That sounds adorable, And maybe I could use that to convince Zach that we should all dress up. I don't think it's going to work, but it could be worth it.
Look what the Californians are doing. We should follow a suit. I don't know how to work on him.
No, well that's not going to work. That's gonna anti work.
All right, never mind, And we hope that you're all out there having a wonderful holiday. Whatever version or variety or tradition you are following. We hope it means one full time with your family, and we also hope that it gives you another way to think about science. That's why on today's epide That's why on today's episode we're going to be breaking down the science of holiday traditions.
I think we should start calling them epipodes, and we should get like toad related facts incorporated into every episode episode.
I think you hopped to that idea little quick.
Oh man, I love funs. That's so great. It's too bad we can't hear the audience groaning though, But.
You know they are, you know they are.
That's right.
So it's our first holiday tradition that we're going to interpret in the name of science.
All right. The first holiday tradition we're tackling today is how the heck does Santa manage to visit about three hundred million children in the world that are distributed in about eighty five million different homes. How does he do that in just one night?
Does Santa have to follow the laws of physics? Is it possible physically for Santa to accomplish this feat? We thought about some of the numbers, especially in light of our recent episode about flight and the physics of it, the mysterious science behind how things stay in the air. And so you're right, Kelly, by my calculations, there are approximately three hundred million children in the world who are expecting Santa to visit, which means eighty five to one
hundred million different homes on Christmas Eve. That's a lot. And if you think about what he's carrying with him, like, that's a lot of presents. If each kid gets a pretty small present. I was thinking, like, you know, an iPod, nano, something really tiny, then he has a pretty big load to carry. It's something like one hundred and fifty thousand tons of presents. And that's got to be a low estimate because some kids are getting you know, air rifles or big Tanka trucks or bicycles.
Yep, yep. Oh, what was the rifle in the Christmas story?
You're going to shoot your eye out with a daisy air rifle?
Yet, there you go, you'll shoot your own kid. Oh that was a classic. My daughter was not crusted with that movie anyway. I haven't like looked at a map and thought about this, but are Christian homes distributed all around the earth or are there regions of the earth that you can skip?
Well, Christians are definitely not equally distributed across the whole earth because there aren't that many for example, living in the Pacific, so you know, the land mass helps you concentrate, so that shrinks where Santa has to go. And also people are not evenly distributed across land, right, so you get like a lot of children you can take care of in Manhattan, for example. And of course not every country has an equal number of Santa expecting children, right.
There are more proportion in the Americas than there are in Africa or in Asia for example, though of course there are all across the world, and in every country you have children who are expecting Santa. So it's actually interesting problem, and it relates to the traveling salesman problem, which is a famous problem in computer science, which is to find the shortest path among a bunch of cities.
And even with like ten or twelve cities, there is a huge number of combinations that the traveling salesman would have to consider to find the shortest path. And it's not a problem we have a fixed solution to. Like, basically, the only way to find the shortest path is to try every possible combination and calculate them and then take the one with the shortest path. But because there's so
many combinations, it's almost impossible to even do that. So now have eighty five million homes that you have to go to and you try to minimize the flight time between them. Basically, Sant has got to have an enormous quantum computer if he wants to solve this problem.
I guess I was wondering if maybe this is what Santa does in the off time, you know, like while the elves are making the toys, but you know those Christian families are moving.
Around, yeah, and having babies and.
Having babies and just yeah, it's complicated. So maybe he has solved this already, and like we should be asking him what the solution is. Maybe he's a mathematician.
Mm hmm, Yeah, maybe he's solved whether P equals NP. Remember we had Scott Aronson on the podcast talking about really hard to solve problems. This is one of the hardest to solve problems, and Santa clearly has figured it out. Because even on the fastest computer, if you ran this problem how to very quickly go from home to home for eighty five million homes, it would take you at least a year on the world supercomputers. So I think that proves that Santa must have mastered quantum computing.
Yeah, no doubt. We should send Scott Aronson up there to visit and make a chat about it, or.
At least we should have the next big quantum computer named something Santa related.
I do like that idea. That's ter cool. Right, that's huge. I like it.
Wait, maybe P equals NP. Maybe NP stands for a north pole. It's been the secret the whole time. It's right in front of the gosh.
That's amazing. Wait, you and I should have a spinoff podcast on conspiracy theories. I'm in.
Santa sasquatch quantum computing, invest in my crypto startup.
Boom right, all the right words right there, Daniel. Yes, we've already got an advertisement for the show done.
But even if Santa does have a huge quantum computer and has figured out the fastest way to get from place to place, he's still got a lot of problems to solve if he's going to figure it out within the laws of physics.
That's right. So you said we've got about one hundred and fifty thousand tons of presents. He's got to distribute those presents at about seven hundred and sixty eight visits per second. Per second that's fast exactly.
That's a lot. And that's assuming that he has like around thirty hours to do it, because you know, as the earth spins and you have time zones, is like a little bit more than a twenty four hour window where people could still technically call it Christmas. This is being pretty generous. I mean, I think most people want their presence like by four am in case their kid gets up early. But if you're generous, you know midnight to seven am or whatever, then you get about thirty
one hours. And that's still a lot of visits and not a lot of time. It means, for example, one to one thousands of a second for each house, you got to land, you got to get down the chimney, you got to eat the cookies, you got to put the present, You've got to get back up the chimney, you got to get back on this leg, and you have to take off. All of these things have to happen within a thousands of a second per house.
Well, and it's some of the families. You have to grab the carrots that people left for the reindeer and feed those to the reindeer. And that was something my family did. So that's another step you can't miss.
Yeah, exactly, and then you have to factor in the travel time between houses also, right, So assuming again that sand has somehow minimized this, I estimated that the total travel time of his trip is going to be around seventy five million miles. That's making some simplifying assumptions about how far apart the houses are around the world. That's a long way to go in thirty one hours. And I hid in the back of my mind this question is like, is Sana going to have to break the
speed of light limit? Santa FTL is not only is he quantum Santa? Is he also like Einstein was wrong? Santa is he?
No, he's not right because he's under that he's not.
Actually, yeah, it turns out he only has to travel about seven hundred miles per second, which is pretty fast. I mean, it's like thirty four hundred times the speed of sound. But it's nowhere near the speed of light. So the speed of light does not interfere with Christmas.
So how much do you think Jeff Bezos has offered Santa for this technology that allows you to deliver packages this quickly?
Who's the logistics master? Right? That's right? Right? Santa should really branch out and compete with Amazon. If he did more than just Christmas, right, if Santa could deliver anything to you right now, like faster than Amazon, Wow, Santa could be rich.
You know what makes me a little nervous though, is last year it was noted that some of the bags the toys came in looked like the same bags Amazon uses when you deliver a gift, So at your house, at my house, there might be a little bit of collaborating going on, so maybe they're sharing secrets. Amazon packages get there like the next day sometimes that's pretty fast.
That's pretty fast, And I definitely don't want Jeff Bezos like learning to fly drones down chimneys just to deliver packages faster like that would be creepy.
Would be creepy, all right, So never mind, Let's hope they're not talking to each other. Could he travel that fast? So, like, at those speeds, is it gonna heat up? Or is he maybe traveling he goes up to space to avoid air friction, that comes back down again real fast.
You can't really avoid the resistance the atmosphere though, because if you come back in you have the re entry He's moving pretty fast. I mean, mock thirty four hundred is very fast to move through the atmosphere. Like I don't hear it, but if Santa really is traveling that fast on Christmas Eve, then there's gonna be some serious sonic booms. And not to mention that, Remember we're talking about a huge amount of cargo. Like we set one hundred and fifty thousand tons of presents. That's about the
same mass as two fully equipped loaded aircraft carriers. So now imagine two aircraft carriers traveling through the atmosphere at mock thirty four hundred. This sounds like the plot of the Avengers, right. Those things are definitely going to burn up. They're going to pressurize the atmosphere in front of them. It's going to turn into plasma. They're going to melt the front of it. He's going to have some really intense heat shielding. Yeah, but what does he have in front?
He's got reindeer. So somehow maybe those reindeer noses are working as heat shields. I don't really understand how that's possible.
I don't think that we have that as an example in the Animal Kingdom yet. That would be pretty incredible I guess maybe he has figured out some invisible heat shielding that can be used. Maybe that's how we explain this. I don't know.
I don't know. That seems like a copa because then you can do invisible anything. Right, Yeah, he's got an invisible warp drive.
That's where the magic happens. Then I guess, so you mentioned those reindeer flying, and let's take a break and talk about how that might have evolved. Okay, and we're back. So Santa has reindeer that fly and bring him around the world somehow without burning up to deliver gifts to all the boys and girls. How do those reindeer fly? So there's a whole field studying the evolution of flights. We have three vertebrate examples where these animals evolved the
ability to fly. So we've got bats, birds, and pterosaurs. That's right, we're going back in time.
Wow, So what you're saying, in the entire history of Earth, only three vertebrates have learned to fly. We got to dig back to dinosaurs to have our third example.
According to the cow Museum website, I was looking at Yes, those are the three examples I saw. The website didn't look super modern. So maybe it was a little bit, but as far as I know, yeah, we've got birds, bats, and pterosaurs.
And what about the evolutionary history there, because I know that people tell us that, like, oh, birds are basically descended from dinosaurs. Does that mean that birds are modern day pterosaurs? Do they come from the same origin? Did that flight involve twice or once?
I think that terosaurs are not dinosaurs.
What pterodactyls are not dinosaurs? Calvin and Hobbes taught me wrong.
That's right, Paradactyls are not dinosaurs. I mean, I hate to ever say anything negative about Calvin and Hobbes and Bill Waterston. Yeah, but you know children are allowed to dream and that is a fictional account of things. So yeah, pterosaurs are not dinosaurs.
So wait, what makes something a dinosaur? All giant reptiles living with the dinosaurs or not dinosaurs?
I'm guessing that's right. Not everything that lived in the time of the dinosaurs were dinosaurs. And we have now maxed out by paleontology knowledge. When I was like eight, could ask me any of this and I could have rattled off the answers.
But you know, oh man, we should have eight year old Kelly on the podcast. That sounds great.
She was a lot more fun.
When I build a time machine, that's the first thing I'll do. So I'll go back in time and ask eight year old you dinosaur questions.
Awesome, sounds good. I hope she's as clever as I seem to remember her being. But I guess we'll find out, all right.
But we were talking about reindeer flight, and you were giving us the context of the evolutionary history of flight pterosaurs, bats, and birds. So it's possible for vertebrates things with bones in them, to learn to take to the air. How does that happen? What are the evolutionary pressures that are needed, and could they possibly apply to a reindeer.
So for a lot of this stuff, you know, we can't go back in time, we can't see it ourselves, but we can look at evolutionary trees and try to see what closely related ancestors were doing and then try
to get a sense for what happened over time. So, for example, it looks like the pterosaurs, they evolved the ability to fly from ground dwelling ancestor, so it looks like they were sort of leaping up into the air and having wings maybe helped them soar or glide for a little while and then but birds seem to have evolved from animals that were up in the trees, and so they jumped out of the trees and then they
would glide. So you've got, you know, bottom up and top down abilities to learn how to fly.
But in both cases there had to be some evolutionary pressure. I mean, you're giving us examples of like how there was proto flight, which somehow got selected for and encouraged. What was the pressure that made these tree jumpers want to fly or these ground leapers want to fly.
There are a couple different hypotheses for what the pressures were. I think the most convincing, or at least the most commonly stated one is that it had something to do with like escaping predators. So if a predator is coming for you and you can jump out of the tree and then glide away, for example, then that helps you get away. And then over time there were all these
additional benefits. So, like gliding is nice, but if you're able to stay in the air for longer and maybe flap your wings, you can get from place to place. Maybe you can find a spot where there's better food. But every step along the way has to have some benefit in order for you know, evolution to continue building on that trait.
And something I don't often hear enough about when it comes to these stories of evolution are the costs. Because I could tell a story about how it would be awesome if I had wings, Like I could escape predators, I could escape traffic, I could hunt better, like I could do all sorts of things. I would love to have wings, Like, obviously there are benefits. Why don't everybody
have wings? And I guess the answer must be that there are costs to having wings which don't pay off for everybody, right, So, like why don't humans have wings?
Well, you know, sometimes evolution is a cruel mistress. I mean, so wings are often like the bones in your arms get sort of repurposed and you end up with like webbing in between. And so you know, bats, if you look at it, it's like the fingerbones have like extended and now there's webbing in between. And so you know, we really benefit from our ability to use our hands, right, so if we could fly, we might you know, lose some of that, and so yeah, there's trade offs or just about anything.
You know, if you asked me like wings or hands, that would be a tough call because wings would be awesome. But boy, who's going to like scratched at my nose if I don't have hands?
Yeah? Well, I mean you can rug your nose on a tree or something.
That doesn't seem very dignified.
Well, humans do tons of undignified things. We could Acclabate's true. But you know one thing you might have noticed is that reindeer don't have wings at all. That's right, Yeah, so what's going on with that? I can't think of any example of an animal that can fly with no wing.
All right, So let's talk a little bit about the physics of reindeer flight. How is it possible to get in the air. All the examples you're giving us for how to get in the air involved having like really low density like birds we know have like hollow bones and bats really have minimal bones because you want to minimize the amount of mass you need to get in the air, and then some huge surface areas that you get lift. And we had a whole episode about how
lift works. And you need either some angle of attack, so the Newtonian force pushes you up as the air particles put down, or you need some airfoil to create pressure difference in velocity difference, or you need both. So the physics of flight is quite complicated, but it always involves wings, right. Even insects have wings, even though their
flight mechanics are completely different. So it's hard to imagine how a reindeer without any wings at all are going to get up in the air, right, Like, physics problem number one is, I don't think their bones are hollow. You know, they are made for like holding a lot of meat and running pretty fast on the ground. Reindeer running like thirty five miles per hour, you need some pretty strong bones for that. I have to hold the muscles.
I did learn, however, that reindeer hair is hollow. So they're living cold places and for insulation, it's nice to have, you know, fluffy hair, and their hair is like little tubes, so it's very low density.
That's great.
Yeah, I mean it's sort of like having the frosting without the cake because you got a much bigger problem to solve just getting the thing off the ground. And then there's the big question of the antlers, right, Like, you don't see a whole lot of flying things with heavy duty antlers. And there's a reason, right, Like what about the pterosaurs? Do they have like really big heads and pokey bones.
I think they had like projections on their heads. I don't know what the point of those was. But they also had like giant weights, perhaps to offset stuff like that.
So I was thinking, if I had to get a bunch of reindeer off the ground, how would I do it? And I was thinking, maybe we're looking in the wrong place. Maybe the physics of reindeer flying is actually about the sleigh, because you never see the reindeer flying by themselves. There's always reindeer plus sleigh. So I thought, maybe it's like asking how does a jet engine fly. It doesn't fly by itself, it flies with a wing. So I thought maybe we should take a more careful look at Santa's
sleigh because potentially that could be like an airfoil. Think off Santa Slay as the wind and the reindeer as the engine. So they're running along the ground and maybe providing enough thrust so you get lyft off Santa's sleigh and then you can take off.
What is that going to get you across the ocean like that might get you off the ground, but then those hooves become helpless.
Yeah, I know the physics doesn't really hold together. That was just like, can I even make a first step here towards somehow getting this thing in the air. There's some obvious problems there, Like number one, you're saying, how do you stay afloat? Right? Like reindeer they can run pretty fast, but then what do they do once they get into the air. Because they don't have wings, they
can't paddle through the air. Though when you see a typical depiction, they're somehow still running through the air, Like, I don't know what they're supposed to be working on. Another big problem even with this idea is they got to be able to take off from a rooftop right, basically from a standstill. Yeah, and reindeer can run it like thirty five miles per hour, But they don't go from zero to thirty five miles per hour instantly, right,
They take some time aim to accelerate. Even a reindeer can't survive like more than a few g or their insides will liquefy the same way humans would. And reindeer speeds are thirty five miles per hour. That's pretty fast, But jets need like one hundred and twenty one hundred and fifty miles per hour going over those airfoils or hitting the angle of attack to take off. So reindeer, I can't see how they could get up to high speeds or accelerate from the rooftop to get fast enough.
The only thing that's left is, like, reindeer have kind of big ears. You know, maybe those ears could flap somehow. Maybe we're just like looking in the wrong place and all the magic is in the ears. So I did a little calculation to think if you treat the ears like wings, how fast would they have to flap to provide enough thrust? And the number I got, which I'm sure has a lot of uncertainty, is about thirty five thousand times per minute.
Oh my gosh, I mean, does that take into account all the weight that they're pulling and the fact that they're teeny tiny with low surface area. No, okay, no, just.
To take off the reindeer the I'm thinking like the reindeer version of a hummingbird here, like like it would be insane, and I think you would notice that happening. I don't see that in the depictions. So I did the best I could, but I couldn't get these reindeer off the rooftop no matter what I did. I just think the physics is not there.
I mean, it wouldn't be a dKu episode if we didn't talk about aliens once or cannibalism, which we've somehow managed to miss. Do you think maybe Santa has access to some alien levitation technology or maybe this is where the magic comes in.
It's certainly possible if you give yourself access to any sort of potential future human technology or alien technology across the galaxy, you might imagine that Santa is using anti gravity technology. I mean, fundamentally, we do not understand what
gravity is or how it works. We have this wonderful theory of gravity general relativity that tells us that mass bends space and space tells mass how to move, and that this weird bending can cause things that look like forces to appear, which is what we call the force of gravity. So the space is bent near the Earth, which is why everything falls towards the center of the Earth.
And in order to avoid falling towards the center of the Earth, you need to be accelerated up or outwards away from the center, which is what the surface of the Earth is doing. That's why it appears that things are moving under gravity when you're standing on the surface of the Earth. What's actually happening is you're accelerating against
the natural force of gravity. That's a long way to say that maybe Santa has some technology that bends space itself so that he can create some pseudo force, basically anti gravity. And if you imagine, like the gravitation a well of the Earth, things would naturally be falling towards it. But a Santa can counteract the bending of space only in his local environment, so that he's not falling towards the center of the Earth. It would look like he's flying.
You would look like there's some great force there. So potentially super advanced aliens or time traveling future humans might have access to space bending technology that to us would look like anti gravity basically levitation. So if we're gonna go for aliens, then that's my solution, Santa, the anti gravity alien.
I feel like there's all kinds of things that we could learn from Santa if he would only come hang out with the rest of us a little bit more. Maybe our scientists holiday should just be when Santa visits and reveals all these secrets to us.
I know he's mastered quantum computing, he's mastered anti gravity. Maybe he's figured out quantum gravity. Right, maybe Santa is a string theorist. Oh my gosh, Santa, please come on the podcast and explain physics to us.
That would be great.
You know, I was gonna say if anybody out there has a connection to Santa, but then I realized anybody can just write to Santa. So let's send a message to Santa and say what we want for Christmas is for him to come on the podcast and explain the universe to us.
That sounds great. All right, Well, Santa, please get in touch with us. That's my only wish for Christmas. And let's take a break, and when we come back, let's talk about Rudolph's shiny nose. All right, and we're back. So our next task is to try to figure out how Rudolph's shiny nose shines. We've got a couple ideas here.
So we discovered what we didn't personally discover. We discovered by doing a tiny bit of research that actually a lot of mammals are fluorescent, which means that when you shine black light on them, they sort of reflect that light back in a variety of different colors. So mammals are fluorescent. So Rudolph could maybe be fluorescent, but that's just reflecting light back and it's not producing light the way it feels like Rudolf's nose is supposed to be doing, so I think he's not fluorescent.
The fluorescence is really interesting from a physics point of view. I mean, what's happening there is a little bit more complex than just reflection. You're absorbing that light, converting into energy, and then emitting light at a different wavelength, right, because you're absorbing ultraviolet light or something else and then emitting at a different wavelength. So it is fascinating, right, Fluorescence
is not just reflection. It's amazing that it exists in so many animals and there's so many biological applications for it. Why do you think animals would have evolved this? Why is fluorescence a thing in an animal kingdom? Yeah?
I don't think we have a great handle on this yet. I think in some cases it seems like it's to attract prey, and other cases it's to attract mates. I think there's probably also a subset of instances where the fluorescence doesn't really have any purpose. It's just kind of an accident. Like the pigment is, you know, I don't know, it's like red or something, and it's meant to signal other animals. But that red pigment also happens to fluoresce
if it's hit with the right wavelength of light. And maybe that doesn't really happen in nature, but it happens in the lab. And so you know, in nature, maybe that fluorescence doesn't do anything because it just kind of doesn't come up that often. But I don't think we know why a lot of mammals are fluorescent, because I think we didn't realize it was until recently.
I was looking at a picture of a bat under a black light and it's like fabulously blue. It's like, wow, maybe bats are like having a party this whole time, and they looked like they were colored in a boring way to us, But the reality is that they're spectacular.
Bat ravees every night, I'm it.
I also remember talking to a friend of mine here at U c Irvine who studies birds and vision and she discovered that a certain kind of bird called the blue tit, is actually emitting in the ultraviolet, and that the birds themselves can see the ultraviolet. And they only discovered this because they smeared some of these blue tits with vasiline, which blocks the ultraviolet, and when you do that, the otherwise very sexually successful tits were now totally ignored by all the females.
Wow.
So that means that the females were selecting the fabulously ultraviolet blue tits.
That is incredible.
Yeah.
There is an incredible chapter in Ed Young's book Immense World, all about different kinds of visions, and he points out that there's lots of animals that can see things that we can't see. And I found that both like absolutely amazing that there's so much as animal behaviorists that maybe we're missing when we study animal behavior because we just don't know what they're seeing, but also like a total
bummer that there are colors that I will never see. Okay, so I think that these deer are not fluorescing, which would be awesome. Maybe they're fluorescing on top of it, but Rudolph's knows. My best guess is that it's bioluminescence, And so bioluminescence is a chemical reaction. So you get this thing called luciferin, and when it combines with oxygen, they produce something called oxyluciferin, and that reaction releases light.
And luciferin as in lucifer.
Luca is like a prefix that means something about light.
Oh I see, yeah, yeah.
So like fireflies, I believe that they've got like luciferin and oxygen like in similar places in their like butts, and then they release luciferase, and that's an enzyme that speeds up the chemical reaction and so it increases the amount of light that's visible. Some animals can do this, like fireflies, but there's also bacteria that can do this.
And there's a lot of animals that bioluminess not because they're doing the reaction themselves, but because they harbor bacteria in these specialized organs, and the bacteria produce the bioluminescns.
Oh that's very cool. Yeah, I love when you can't do it yourself you outsource it to microbes.
Symbiosis. Pretty cool. How would this have evolved for Rudolph? One possibility is for camouflage. So we see a lot of bioluminescence happening in the ocean, and often it's being used at night. So the deal is, if you're an animal that's swimming around, you know, under the water surface in the ocean, the light reflects off the moon and into the water and it leaves little like trickles or
streams of light coming through. And so if you as an animal moving around in the ocean, have to watch out because if you cast a shadow, then predators underneath you can see the shadow that you cast and then know that they can go to eat you. And so there's a lot of animals that have either their own bioluminescence or they store organisms that release light in ways that mimics the way moonlight trickles down through the ocean.
So that's fascinating because your intuition is if you want to hide, you should be dark. But if the background is shimmery, you actually want to be shimmery to blend in with the shimmery background, because otherwise your shadow makes you obvious.
Yeah, exactly, And so I think the most famous example of this are bobtail squid, and the bobtail squid have a compartment that stores these bioluminescing bacteria, and they feed the bacteria things like sugars and stuff to make them happy and keep them reproducing, and it casts enough light that sort of cancels out the shadow that's made by the squid. So this is like a famous symbiosis where
squid and bacteria live together nicely. So it could be that maybe why so few of us see Santa's sleigh at night is because there's some bioluminescent tricks canceling out Santa's sleigh shadow. But I think maybe that's not what's happening, because the light is facing in the wrong direction, right.
And also, we're talking about just one reindeer here, right, Rudolph is the only one with the shiny news. So not only do you have to explain how Rudolph evolved this, but how you have like a subset of reindeer with shiny noses and most of the population doesn't.
I have concluded that Rudolph is probably a separate species.
Oh, I see, all right, his.
Species evolved this, but he may be the last one left of his species. Because no, this is tragic, I know, because another purpose of bioluminescence is to attract mates, and it just doesn't seem to be working for poor Rudolph.
That's right.
A final purpose for this bioluminescence is to attract prey. There's an interesting story with cookie cutter sharks where they've got this like on their abdomen where it kind of looks like the light sort of coming down through the ocean, but then there's a blank patch, and the hypothesis is that blank patch looks like a fish that's swimming above and is creating a shadow, but you're actually just looking
at the belly of a cookie cutter shark. And so when a predator comes up, thinking it's gonna eat a fish, the cookie cutter shark quickly spins around and they take like a cookie cutter shaped chunk out of the animal and then they swim away really quick. So maybe Rudolph is predatory.
What he's not a grass munching vegetarian like the other reindeer.
It's unclear. It's unclear. So the question is, I guess, you know, is Rudolph another species or does he maybe just happen to have a weird bioluminescent bacterial infection in his nose? And so maybe he is the same species, it doesn't benefit him at all, and he just has this infection he can't clear.
That could be certainly, It's amazing how these things happen, right, Like, obviously none of this is designed or organized. It means that sometime in history, like one of these squid or one of these shark like developed some infection and it turned out to be beneficial. Right that's crazy.
Yeah, So an infection implies a negative outcome. So it could have been that these bioluminescing bacteria ended up invading some small part of the bobtail squid and they just lived there and didn't hurt the bobtail squid. But the ones who harbored the bacteria just did better, and over time it was better to have more bacteria, So some of them, you know, ended up feeding them with sugars. Blah blah blah. It doesn't have to start negatively, but it could have, right.
No, I don't even think about microbes negatively. I think I've just been propagandized by my wife who like helps me appreciate like basically microbes are essential for everything we do in every part of our lives. Like sterile humans just could not survive, right, and so we're totally colonized by all sorts of micros, bacteria and phages and all sorts of crazy stuff easing ecosystem that keeps us all going. But it's crazy when that changes, when you get colonized
by new criter, which changes what you could accomplish. It makes me wonder, like why humans never learn to glow? Right? I can imagine some scenarios where all these stories you tell, I can imagine some scenario where it could apply to humans right, where we could attract prey, or we could camouflage better or something.
Yeah, you know, I guess it's worth noting that most of the examples of animals that bioluminous are living in aquatic environments. It seems to be much more beneficial there. So, yes, we have fireflies, but they're pretty unique in their ability to buy iluminess on land. So it might be that the benefits on Earth are just not that big, which makes it even more surprising that Rudolph is able to do it.
Yeah, though, there are lots of land creators that fluoresce, right, so like under a black light will glow cool colors or something. But humans know you got to wear a crazy T shirt for that at your next dance party.
Absolutely. Yeah, Ah, the nineties were wild time.
But speaking of lighting, there's another holiday that happens right around the same time of year. It's not just Christmas. So let's talk about the science of Honkkah, the festival of lights.
That was a beautiful transition. Yes, let's do that. Tell me about the Honkah story. I did marry a Jewish man, so I'm familiar with it. But in case other people aren't.
So the story of Honkkah, as most of the stories from the Old Testament center around battles, those lots of these battles, Jews were always getting involved in wars. And this is a battle between the Jews and the Maccabees over the temple. And it raged back and forth, and the Jews lost the temple and then recovered it and they won the battle. But in the end, when they got back into the temple, they found that most of
the oil that they used to light the lamps. This is ali of oil in the original temple, which of course now destroyed, had been spoiled. And you know, this is like the center of Judaism, and so you need oil that's like pure and has been blessed in all this kind of stuff. You can't use spoiled oil. And they only had a little bit of oil left. They had oil enough to keep the lamps going for one day,
and it's essential, so you keep the lamps burning. And it takes about eight days to make more oil, to press it and purify it and bless it and all this stuff. So the pipeline is eight days long. It's been interrupted. You have one day supply. So they're like, uh, oh, we got to get these lamps going, but there's no way they're going to last eight days. And so the miracle of Honkkah is somehow a one day supply of
oil lasted for eight days. It lasted until they could get a fresh supply, and so the lamp never went out.
Amazing. And just to be clear, and it's not being used for cooking or for heating. It's being used for religious purposes and lighting.
Up the temple. Yeah, it's a ritual essentially, it's like the eternal flame, right, Okay, got it. Got And so even before we dig into like the miracle of Honkkah, I've always been amazed at the technology of lamps like, it's kind of incredible. You have this fuel you want to burn, but you want to burn it a little bit at a time, so you have a low, consistent glow. And there is this amazing bit of technology which it comes to us from the ancient world, which is the wick.
You don't want to just like set your oil ablaze because just like all burn out and pollute the indoors and you won't have a lighting for very long. So they have this incredible technology of the wick, which essentially pulls a little bit of fuel from your main supply and burns only a little bit at a time, giving you a constant glow. And it's so simple. It's basically just you put a string in your fuel. It's one of these genius bits of technology that must have been.
A huge improvement in quality of life when that was figured out. Like being able to read all night by the light of a lamp as opposed to just needing to pick and choose, when you're going to be able to burn your big supply of oil all at once.
That sounds incredible, It is incredible, and it's something that humans have been doing for thousands of years. We're telling a story from the Old Testament, so it's a couple thousand years old. But wick technology has been found by archaeologists dating back at least three thousand BC. Right, so the ancient Egyptians used wicks. This is something people figured
out a long long time ago, and probably independently. We think that the Chinese used rice paper to create wicks and made wax out of insects and seeds and all sorts of stuff. So this is like kind of ingenious but also fairly simple, and so people discovered a long time ago.
We are a pretty clever species. So is one possibility then that when they came back into the temple and they noticed that a lot of the oil had gone bad, they switched to using wicks and it used it more efficiently. Or that's not the miracle.
No, they were using wicks the whole time. Yeah, absolutely, wick technology was pretty well established at that point. I also love the word wick because the word tells you what it does. Right, Like everybody's familiar with like fancy shirts that wick the sweat away from your body, right, that's what wick means. It like slurps up the liquid. It's wicking the liquid. Anyway, That's enough about the science
of wicks. They're sort of incredible. So then let's dig into the miracle of it, right, how could you possibly use science to make your lamp burn longer than you have a fuel supply for? And the crucial thing is you have to keep it burning the same brightness. You can't just like turn it down and be like, oh, I'm going to make it last for eight days by having it be an eighth as bright. You got to keep it as bright and somehow get more energy out
of it. Right, And so unless you're going to say like, oh, there was fusion happening or some other sort of energy source to pull additional energy out of the fuel, seems pretty implausible. The only thing I could think of, and I'm basically going back to the same Santa miracle, is somehow bending of space and time. Because we know that there is a way in physics to have time slow down. If, for example, I sent Kelly in orbit near a black hole, I will see her clocks running slow, and she'll see
my clocks running more quickly. And so, for example, if I could create a special bending of space in the vicinity of these lamps, I could slow down time for the lamps and then far away from the lamps, even a few meters, I would observe clocks running slowly. So essentially one day for the lamp would be like eight days for me.
And during that time you were making new oil.
During that time, I was making new oil. And so this requires you to like somehow know how to bend space and time. But you know, if we're gonna give Santa that power, then we can give the ancient Jews that power. Also. There are some wrinkles here though, because if the clock is running slower, you would argue that it's also producing photons less often, and so technically you'd be getting photons at one eighth the rate. You know, It's sort of like if you're getting a video stream
from a spaceship going near the speed of light? Are you getting those frames at the same rate that they're being produced? Does it look slow motion to you? You could go down a whole rabbit hole here the science of Hanukkah. Basically there's no way to really make it work. But that's the best I could come up with.
Well, I mean it was a noble attempt, I think, yeah.
And you know, though it's fun to use these as a launching off place to talk about science and how you accomplish these things. We all recognize the point of these stories is not to have a scientific explanation their mythology and their nice stories to tell about our history and to have traditions and to all gather together over the holidays and enjoy time with our families. So we don't mean to try to ruin these things for you
by trying to turn them into science. We just mean to use them as a fun place to have science conversations on these topics.
That's right. The miraculous nature of these stories is what makes them so exciting to tell the kids.
Exactly, and having stories in common is what makes us human. And so everybody out there, hope you enjoyed this little dose of science and then you enjoy your time with your family on the holidays.
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