Hi, I'm Rose Rimmler filling in for Wendy Zuckerman.
She fell into some quicksand.
I'm just kidding.
She'll be back soon.
And you're listening to Science Versus from Gimlet.
This is the show that pits facts against misfortune.
And I'm here in the studio with our producer, Meryl Horn.
Hi, Meryl.
Hi, Rose.
So, what are we doing here today?
We are here because it's the 13th season of Science Versus.
Oh, wow.
Yeah, I've come a long way, baby.
Yeah.
So, we've decided to look at the number 13 and whether there is actually anything that's
unlucky about it.
So, why do people think 13 is unlucky in the first place?
Most people seem to think it comes from the Bible because according to the Bible at the
Last Supper, there were 13 people there and, you know, that's a bad supper because that's
the one that happened right before Jesus was crucified.
It was the last one.
Yeah.
Okay, yeah.
I see why that's bad.
And according to a Gallup poll, about 9% of Americans are so afraid of the number 13 that
if they were assigned the 13th room number or floor at a hotel, they'd like demand a
room change.
Wow.
9%.
That's more than I would have thought.
Yeah.
That's a lot of people, actually.
I know, right?
So, and a lot of hotels actually just don't have the 13th floor, so they can avoid this
altogether.
That's wise.
So, is there anything to actually worry about?
Do bad things happen on the 13th floor, like two little girls appear at the end of the
hallway?
We don't have any science on that, but there surprisingly is some science on whether the
number 13 is generally unlucky.
So, like, there's this one paper I found from the 90s that was done in the UK, and they
actually found that more people were sent to the hospital from traffic accidents on
Friday the 13th.
Oh.
They compared it to what happened on Friday the 6th.
So they concluded that, quote, Friday the 13th is unlucky for some, unquote.
Wow.
But I'm not sure what to make of that.
Like, it's kind of old, it's a little weird, so I went looking for something a little better,
and I did find one that was super interesting.
So this study doesn't look at 13, it actually looks at the number 4.
That number is considered unlucky by many East Asian people, and that's because the
number 4 sounds really similar to death in several languages, like Cantonese, Mandarin,
and Japanese.
The word for the number 4 sounds like the word for death.
Yeah.
Yeah, exactly.
And so what the study did is they looked at over 200,000 deaths of Chinese and Japanese
Americans in the U.S. to see if more people died on the fourth of the month compared to
other days of the month.
So let me send you a graph of what they found.
Wow, there is a spike.
This is like a bar chart of the number of people who died on certain days of the month.
There's a spike on the fourth day of the month.
Yeah.
Like a clear spike.
Yeah, more people did die on the fourth of the month.
Whoa.
Yeah.
That's wild.
I know, right?
And so the authors aren't sure if this is just from the stress of the number 4 itself
or maybe it's like the stress of the number 4 leads more people to do other unhealthy
stuff, like maybe drink more alcohol on that day.
And then they compared this with just white Americans and they didn't see that spike.
Like it was specific to Japanese and Chinese Americans who are more likely to be afraid
of the number 4.
I mean, this is just one study and the difference wasn't that big, but it does seem like one
of these cases where even though there is nothing inherently bad about the number 4,
the fact that people believe that there is something unlucky could lead to real effects.
Something about the belief of the thing makes the thing real.
Yeah, exactly.
Okay, so for today, we're going to talk about good old unlucky 13.
We're going to tell you science stories about both the number 13 and about luck more generally.
You're going to hear about one of the weirdest creatures on the planet and we'll talk about
a hot new telescope that's trying to look back 13 billion years ago to uncover the secrets
of the universe.
And we'll talk about a squeaky superstition that involves a rat as the tooth fairy.
So get ready.
All those stories are coming up right after the break.
Welcome back.
This is our 13th season of Science Versus, so to celebrate, we're looking into stories
about the number 13 or about luck.
And our first story is the tale of a 13 legged animal.
A few years ago, a diver in Bali uploaded a video of a strange creature creeping along
the sea floor.
The body of the creature looks kind of like someone cut up an old nubbly towel into 13
strips while the head looks like a small balloon, a sphere that inflates two, three times its
size and then shrinks back and then expands and then shrinks back again.
There's a crease in the middle of this balloon head, which gives it a vibe that is distinctly
butt-like.
You can see it on our Instagram or on our show page on Spotify.
This creature was so weird looking that it caused a bit of a media sensation.
The video went viral and made headlines with the Daily Mail screaming out, the mysterious
creature with 13 legs and a jelly head, the Mirror calling it a mysterious alien creature.
And the Sun said this bizarre creature left viewers baffled.
I have a soft spot for spineless, gelatinous ocean creatures, and I didn't know what
this was any more than the Daily Mail did.
So I wanted to know, what exactly is this 13 legged sea monster?
How could any creature have 13 legs?
If you have an odd number of legs, wouldn't you just sort of go round and round in circles?
Luckily, I found someone who has seen this mysterious creature in the flesh.
I arranged to meet him at a tavern on a storm-tossed bay, where over a pine aisle, he spun me a
tale of the sea.
Hi.
Hi, Rose.
Actually, I called him on Zoom.
Nice to see you.
Nice to meet you.
His name is Julian Evans, and he's a marine biologist at the University of Malta.
Malta is a small island country in the middle of the Mediterranean Sea, and he told me the
story of his encounter with this freaky beast.
It was an early fall day a few years back.
He was scuba diving with a colleague, doing a survey of the sea floor.
They were about 60 feet below the surface, and the water was nice and clear.
Off in the distance, they saw something very weird.
There were these blobs of jelly-like creatures just standing there, sitting there on the
bottom, moving about really slowly.
A group of strange creatures on the sandy bottom.
He and his dive buddy swam closer.
And obviously, when you see something on the seabed that looks unfamiliar, your first guess
is that I'm too far.
I just need to get closer, and then I'll recognize what this thing is.
But the closer we got, the weirder it became.
Julian was baffled, and baffled by being baffled.
He's literally a marine biologist who grew up in Malta.
Why had he never seen this creature before?
And it didn't seem like his dive buddy, who had logged thousands of dives herself, had
either.
And we both looked at each other sort of…
I mean, I could see her facial expression from behind the mask, trying to communicate
that I've never seen this before, what is it?
Julian watched its strange inflatable head, expanding and contracting.
Initially, I mean, I had no idea what they were doing, but then looking closely, it became
clearer that they have like a big mouth, which they were extending over the seabed.
Julian realized that they were actually hunting.
He saw that when the head expanded, it made a sort of dome over the seafloor, capturing
little creatures that happened to be there, like crabs and snails.
If you imagine yourself as being the crab, right?
And suddenly you're enveloped by this gelatinous thing, which then sort of closes upon you
and there's no room for escape.
So that's the beginning of the end.
The crab is then swallowed whole and pulverized by the animal's gizzard-like stomach.
Ingenious.
But that still leaves some questions unanswered.
Why does its head look like a butt?
Like a butt.
So in some pictures, you get that impression, right?
Don't you?
It's like two cheeks.
Yeah.
The crease, it turns out, is the opening of the mouth.
When Julian got back on land, he figured out that this was a sea slug called Malibe viridis.
So not an alien.
And you know, slugs famously don't have legs.
But all those articles were flipping their lids about the 13 legs on this creature.
So I asked Julian, what's that about?
They're not actually legs.
They're not used to move.
These paddle-like things protruding off its body are actually structures called cerata.
They basically help the animal breathe.
And they also have a special superpower.
The slug can drop them at will and regenerate them later.
And that comes in handy if the slug is being attacked by a predator.
Like if a fish nibbles at one, the slug can just sever it.
So if it gets bitten, it actually loses one of them.
And that gives it a chance to try to escape.
And in that way, the idea is to give the predator a bit.
Something they can work on, they can chew on.
And in the meantime, the main animal, so to speak, missing a body part, can try to run
away to escape before the predator realizes that it's gone.
Body part dropped as a decoy, the slug can run away.
Well, not run exactly.
I mean, remember, it doesn't actually have legs.
It'll sort of squirm away.
The other big thing the headlines got wrong is that there aren't necessarily 13 of these
cerata.
As far as we can tell, they can have anywhere from five to 20.
The one Julian photographed had nine.
Maybe that variation is because they shed them so casually.
So unlucky 13, it's not a characteristic of the species.
This brings me back to the question of luck.
Do you think that you were lucky to have stumbled on this creature?
Well, in a way, yes.
I guess I'm one of only very few people in my country has seen these.
So in that sense, I seem to have been in the right place at the right time.
So I guess you can say that that is lucky.
Milipe Viridis usually lives in tropical places like the Indian Ocean.
But in recent years, it's been seen more often in new places where it hadn't been seen before.
Julian and his dive buddy were the first scientists to report seeing it in Malta.
And that suggests it might be starting to set up shop in the Mediterranean, like a lot
of invasive species do.
The fact that we saw it means that we have another species that doesn't belong here,
which has arrived.
Invasive species are a big problem in the Mediterranean.
Yes, I think the Mediterranean has been called the most invaded sea in the world.
Oh.
It's really bad.
And why?
Why is the Mediterranean such a hotspot?
Well, first of all, there's the Suez Canal.
The Suez Canal.
It's an artificial trench that connects the Mediterranean and the Red Sea.
It's where that big ship got stuck a couple years ago.
Remember that?
Well, that canal was opened in 1869, creating a passage between Europe and Asia, so ships
don't have to go all the way around Africa.
And ever since then, new species have been swimming, floating, or hitching a ride through
the canal and into the Mediterranean.
And so it was lucky for your experience as a scientist and for this conversation that
you stumbled across this group because it's rare, but it's unlucky that they're there
at all, really.
Exactly.
So we don't know what this slug could do to the Mediterranean.
Maybe nothing, but it might be something very weird.
We'll just have to cross our fingers and knock on wood, maybe?
When we come back, we're going to leave this world altogether and explore the entire universe.
That's after the break.
Welcome back.
It's time to make some space for space.
Here's producer Disha Bhagat.
When I started thinking about what story to tell about luckiness or unluckiness, I thought
of the James Webb Space Telescope.
I had been following it along as it was coming together and it kept hitting roadblocks.
Like maybe it wasn't written in the stars at all.
Okay, so here's what happened.
Scientists proposed the idea for this new telescope way back in 1996 and they got to
work pretty soon after that, but it didn't all go according to plan.
This thing is kind of complicated, so the road was a bit rocky.
And back in 2011, they almost killed the whole project, but it continued along and the telescope
was supposed to launch in 2018.
Then it got delayed.
Technical challenges.
Then delayed again, COVID-19 and delayed again, bad weather.
All together, it got delayed eight times.
We finally got lucky.
The James Webb Space Telescope launched on December 25th, 2021, 25 years after the whole
thing started.
It definitely feels lucky, but I think it's really the result of a lot of hard work by
a lot of people.
This is Jehan Kartaltope.
She's an astrophysicist and an associate professor at the Rochester Institute of Technology.
I mean, it was something that was really planned and developed for decades, really.
People all over the world working together for many, many years and they tested and tested
and tested just because you don't want anything to go wrong.
And now that this telescope is out in space, it'll hang out about a million miles from
Earth also orbiting the sun.
The idea is that this telescope can look further than any other telescope in history and take
way better pictures of what's out there.
Now that it's all set up, the fun starts.
They get to play around with the shiny new toy and learn how to use it.
For these first projects, teams from all over the world submitted proposals for how they
wanted to test the telescope, explore stuff and share what they'll find with the other
scientists.
And weirdly, from all the teams submitting proposals to test out the telescope, there
were 13 projects that got accepted.
13!
And one was Jehan's.
Yeah, it was a big deal.
It was very exciting.
Did you feel lucky that like, wow, we're like one of the 13?
We definitely felt lucky and kind of honored to have the opportunity to be among the first
users of the telescope.
Jehan's project is basically to use the telescope to look at some of the earliest galaxies in
the universe.
And this means her team is looking back in time.
That's because when things are far away, it takes a long time for their light to reach
us.
For the nearest stars, it can take years, galaxies, millions to billions of years.
We're really observing the most distant galaxies as they were billions of years ago because
that's how long it took their light to reach us.
Scientists like Jehan hope that by looking at all this, it'll help them understand how
the universe came to be.
You're basically trying to get as close to like the Big Bang that we know and then seeing
what happened.
Exactly.
The universe was a very different place than it is today, right?
It was a lot denser.
At first it was very hot.
Once elements could form, all we really had was hydrogen and helium.
Hydrogen and helium, those are the most basic elements we have.
And somehow out of that soup of simple stuff, we got stars.
And we still don't understand how that happened.
Like what ignited that spark?
We call it first light.
So how did the first galaxies and first stars form in the universe?
Before they could start looking back through the universe's history, they had to wait.
Because once telescope launched, it took several months for it to get fully set up.
Then came the moment in July when Jehan's team was finally able to see what the web
saw.
We were all in a room together working on things and we kind of all gather around one
person's computer screen to look at images as they came up and then, oh, look at that
one.
Oh, look at that one.
And yeah, that was a lot of fun.
It felt like being an explorer, you know, and just trying to find unknown things and
treasure hunt and finding like the cool things.
Maybe you've seen some of the early images from web.
There's this one showing red space dust.
It almost looks like an outstretched hand in the night sky.
They call it the pillars of creation.
It's where new stars are being born from clouds of gas and dust.
Images like these are some of the clearest that we've ever captured.
And as Jehan's team hunts for galaxies, they've already had some surprises.
I would say the biggest surprise that we've seen so far is that detecting these galaxies
has actually been really easy.
We've found more of them than we thought we did.
So in one way, that's really exciting.
So that kind of changes our picture of that very early time period and how the first stars
were able to form and that when they started forming is even earlier than we initially
thought.
Oh, OK.
So what you're seeing is like you thought that like, oh, we're getting like close to
the beginning.
But it's like, no, this the beginning is even like earlier.
Yeah.
Does it show that the universe is older than we thought then?
So no, that doesn't do that because we have a very good, a good handle on how old the
universe is.
And speaking of the age of the universe, guess how old it is?
13 billion years.
Well, there's some rounding, right?
Our universe is probably closer to 14 because it's, you know, 13 point something.
OK, OK, 13.8 billion years.
Anyway, just imagine as we go about our days, the Webb Telescope will be chugging along,
looking at stuff like black holes, stars, exoplanets.
So we're going to be hearing a lot more about the past 13 billion years.
Lucky us.
All right, we're bringing you back down to earth for this last story.
Like we spoke about at the top of the episode, there are more unlucky numbers lurking around
the world than just the number 13.
Here's producer Michelle Dang on an unlucky number and superstition that haunts her personally.
Yeah, so in Vietnam, where my family is from, a big fat unlucky number is the number three.
Like I've always heard that you should never take a photo with three people in it.
Some say it curses the person in the middle for an early death.
So when I'm with certain family members, there's always this mad reshuffle of people
before the shutter goes off.
Like it can be two, four, more than that, but not three.
That's Michelle's mom.
Yeah, that's my mom.
All this talk of superstitions got me thinking of another one she's told me.
One that she's believed in while growing up in Vietnam.
Instead of the tooth fairy, she had a squeakier version that did not involve putting your
tooth under a pillow.
When I was young, each time I lost my tooth, my mom would say, bring your tooth and throw
it onto the roof.
Yeah, you throw it up onto the roof for a really specific reason.
Because you want a rat to find it and pick it up.
Yes, a rat.
Basically, you throw your baby tooth up there for them to snatch up and hope that in exchange,
they give you some luck on your incoming one.
The rat, they always have like two strong front teeth.
You throw it up on the roof and then you make a prayer.
Which would sound something like this.
The rat, Vietnamese call it Juc.
So I would say, hey Juc, I give you my old tooth.
Please give me your new tooth.
Like a tooth just like yours.
Yeah, yeah, yeah.
A strong, healthy tooth just like yours.
Pretty simple, right?
Basically, instead of the tooth fairy, it's the rat fairy.
Not very cash money, just a wish, a blessing for a big, healthy, strong tooth to come in.
What do you think the rat fairy looks like?
A rat.
Like a normal rat?
I was hoping it's a white rat.
Like a lab rat?
Because the tooth is white.
Now, yeah, the superstition when she told me about it was very silly to me.
I mean, I just had the tooth fairy growing up who graciously gave me a $20 bill once.
So hearing about this rat fairy stuck with me like tartar.
Like is it based on something real?
Do rats really have teeth to strive for and are they that strong?
So step one, I Googled and all these pest control sites came up with these mind blowing
claims about just how strong rat teeth are.
And they make them sound totally outlandish.
Take this list for example.
Can rats chew through wood?
Yes.
Can rats chew through brick?
Yes.
Can rats chew through concrete?
Yes.
Okay, but the most shocking was this figure that kept popping up.
Apparently, their jaws can exert up to 12 tons per square inch, six times the bite force
of a great white shark.
What?
Six fold the bite force of a great white shark?
Is that true?
It was time to find myself an expert.
So meet Philip Cox.
He's an associate professor in anatomy at University College London.
His specialty is the mammalian skull, but he's very keen on rodents.
And well, he quickly debunked the shark thing for me.
Imagine, I mean, I've been bitten by a rat in a lab.
Oh, you have?
Yeah, it would have taken my entire finger off if that were the case, you know, what
was a little nip through the skin.
If it were six fold the great white, yes.
Personal bite forces are often reported online in units of pressure, like tons per square
inch.
And that's wrong.
It's also confusing to compare the bite of a rat to a great white shark in terms of pressure.
The rat's bite can have a very high pressure because its teeth are really small.
But if we do really want to compare the bite forces of these animals, we have the numbers.
We've spent a lot of time modeling and analyzing rat jaws in the lab.
And what he knows is that the average brown rat can bite with the force of about 30 newtons.
Newtons are the standard unit of force used in science.
And the bite of a great white shark can go into the thousands of newtons.
So let's not have a rat square up against the great white anytime soon.
But let me tell you, these little guys still have a pretty wicked set of chompers.
Okay, let's zoom out a moment.
If we look at all rodents, big and small, from the capybara, beavers, flying squirrels
to rats and mice.
They're a really, really fascinating group.
They are the largest group of mammals, so there's about two and a half thousand species
alive today.
That's 40 to 45% of all living mammals.
So they are doing something amazing and successful.
Yeah, nearly half of all the types of mammals on our planet are rodents.
Like, what the f***?
And brace yourself.
I'm very excited to tell you that rodents, this big motley crew, all have one huge thing
in common.
It's the teeth.
So all rodents have a single pair of ever-growing incisors in their upper and lower jaws.
They all have them, those four weirdly isolated, large, curvy teeth that basically keep growing
and growing throughout their entire life.
These are the teeth that my mom wished for, that all the rats of the world have.
Which is obviously an amazing thing to have, because then you can start eating things and
not worrying about if you're going to break your teeth, because there's always more
tooth to come behind.
Seriously, a pretty nifty tool.
Phillips says they have clever construction too.
They have this really hard layer of enamel in front that's better than ours, because
it has more iron compounds in it.
It's what makes their teeth more yellowy.
But they also have this softer layer of tooth in the back, which wears down way quicker
than the front.
And you end up with a really nice, sharp, chisel-like blade.
And it allows them to access all kinds of different foodstuffs.
Okay, so ever-growing teeth that are super sharp and quite hard.
It kind of sounds like, yes, these teeth are something to be desired, because they're
just really darn good for eating and getting through things.
And it's actually true that rats can chew through things that we would want nowhere
near our teeth.
Things like old brick and concrete, those claims are true.
They've even gotten through things like rusted metal.
You know, it must be also a sort of a real continuous period of time that they're sat
there just wearing away.
And you know, I don't think it's that their teeth are harder than the things that they
are gnawing.
It's just that over time, they are able to keep going because the tooth keeps coming
so they can keep gnawing at the same place and eventually sort of wear this material
down.
Yeah, so they're super persistent.
And these critters are also just about everywhere.
Take the brown rat, for example.
Phillips says if you look up a map of their global distribution, the only places they're
thought to be totally absent are Antarctica, the Arctic Circle, and apparently the province
of Alberta in Canada.
They wiped out all their rats in the 50s and have claimed to be rat-free ever since.
But other than that, they're pretty much everywhere across the globe.
It lives alongside humans, it's followed us around the world, and it's been incredibly
successful and maybe, just maybe, partly that's because wherever it goes, it can find something
to eat.
Yeah, Phillips' working hypothesis is that the rats' wild success really has to do with
their jaws and their teeth.
So when it comes to the rat fairy, if there is a rat fairy, would you like your teeth
to be blessed by the rat fairy?
Would you like a rat's teeth?
Oh, of course.
Absolutely.
If I had the opportunity, I would definitely throw my teeth on the roof.
Is that what you do for the rats?
Yes.
Yeah, yeah.
So they're that good.
Yeah.
I think it would only be fair that they get to look at my teeth since I've spent a lot
of time looking at theirs so much.
That's Science Versus.
Thanks for sticking with us for 13 seasons, or if you're new, thanks for joining us.
We'll be back next week with our final episode of season 13, where we'll be diving into Adderall
and ADHD.
Hello.
Hi, Adisha Bhagat.
Hey, Rose.
How many citations are in this week's episode?
There are 88.
Okay, 88.
And so if people want to check out these 88 citations, where should they go?
They can go to our show notes and there will be links to their transcript and they're all
there.
Sounds good.
Do you have any superstitions of your own that you follow?
Not really, but I remember there being a superstition in our culture that you shouldn't cut your
nails in the dark.
Not in the dark, as in like, it's dark outside.
So you shouldn't cut your nails at night?
Yes.
Oh.
And I think there was a reason behind it because it would be dangerous before there was light
and stuff, but now it's like, you could do it whenever you want.
Well, thanks, Disha.
All right.
Thanks, Rose.
Bye.
Okay.
Talk to you later.
Bye.
And make sure to check out our Instagram to see pictures of the sea slug and pictures
from the James Webb telescope and there's lots of other good stuff there.
And you can also check some of that stuff out on our Spotify clips.
This episode was produced by me, Rose Rimmeler, as well as Michelle Deng, Meryl Horn, and
Disha Bhagat.
We're edited by Blythe Terrell, Wendy Zuckerman is our executive producer, fact checking by
Eva Dasher, mix and sound design by Bumi Hidaka, music written by Bumi Hidaka, Emma Munger,
Bobby Lord, and Peter Leonard.
And big thanks to the researchers we spoke to, including Professor Eduardo Fernandez
Doquet, Dr. Ron Wasserstein, Professor Sander Greenland, Professor Natalie Batalia, and
Dr. Terry Gosliner.
Special thanks to Jen Han and Jonah Delso.