June 8, 2018 • 42 mins
Sure, invisibility is about Harry Potter cloaks and invisible inks. But it’s so much more than that, too! From the way butterflies see a secret world of light that humans can’t, to the reason polar bears are completely undetectable to infrared cameras, there’s a whole big world you ought to hear about… even if you can’t see it. Featuring author Bob Berman.
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Speaker 1 (00:00):
Guess what, mango, what's that? Will? I was reading this
old story about a bank robbery that happened in so
this guy walks into two banks, one after the other.
He has no mask and no face cover. I mean,
it didn't seem like he was trying to hide himself.
And he gets caught on camera pretty clearly, and so
obviously he's apprehended not long after that. But the weird
(00:21):
thing is when the cops come fro him, he was
totally baffled. Well, he kept saying, I was wearing the juice.
The juice, Well, apparently he'd poured lemon juice all over
his face because he knew it could be used as
this invisible ink for writing. And the poor guy, he
was really bewildered because he said he tested it out,
and the cops pressed him for details, and he said
(00:41):
the lemon juice had gotten in his eyes the first
time when he poured it all over his face, and
then he took a selfie to see if it had worked.
And the combination of squinting and not being accustomed to
taking his own photo, I mean, this this was well,
it made him take a photograph that he wasn't in
and he just believed that he was invisible. Oh no,
I know you almost feel bad for the guy, but
(01:03):
you know, reading up on his invisible face juice made
me wonder what is the science of invisibility and what
are some of the things going on that we can't see?
And where is my invisibility cloak? So let's dive in.
(01:28):
Y Hey, their podcast listeners, Welcome to Part Time Genius.
I'm Will Pearson and as always I'm joined by my
good friend Man Guesh, I'll Ticketer and over there on
the other side of the glass with the biggest smile
that you can't see is Tristan McNeil, our producer, And
on today's show, we're taking a WorldWind tour of our
(01:49):
invisible world and trying to get a better grasp of
all things unseen. You know, the idea of invisibility is
fascinated mankind for thousands of years. It's parts of our
myths and our folklore and our pop culture and you know,
even our psychology. Of course, there are lots of different
kinds of invisibility. So this will be a super fun
Hodgepodge episode where we cover as much as possible. We'll
(02:10):
talk to a couple of insightful authors who have devoted
years of study to stuff we can't see. So who
do we have on the line today, Mango, Today we're
talking to Bob Berman, one of America's top astronomy writers
and author of a brand new book about the curious
history of invisible light. It's called Zapped, and it's incredible
and we'll have some wonderful quizzes along the way as usual.
All right, So, in honor of Bob's new book, I
(02:30):
want to dive straight into the science and talk about light,
and more specifically invisible light. You know, obviously there are
large portions of the electromagnetic spectrum that we have no
trouble observing, but there's also a huge part that's totally
invisible to us. That's the part that includes things like
ultra violet light and for red light, radio waves, microwaves,
X rays, gamma raves, you know, all that good stuff. Yeah.
(02:52):
I mean, I always knew there were parts of the
spectrum beyond our range of vision, just like you know
there's sounds outside the limits of human hearing. But reading
Bob's book put the vastness of light in a completely
new perspective for me, and it really blew me away.
So Bourmon rights, there's more light in the universe than
anything else. So if you were to add up every
individual light photon in the cosmos, they would account for
(03:14):
nine point of everything there is. And those forms of
invisible light you listed off, that actually makes up the
vast majority of the light. I actually can't wrap my
head around that fact, but it seems unbelievable. But you know,
our eyes are designed to recognize only the Sun's most
abundant energy, so we really can only see the colors
(03:34):
that the Sun emits most strongly. And even though the
whole universe is light, the bulk of it, it's completely
invisible to us. We've actually figured out all kinds of
ingenious ways to measure and observe forms of invisible light.
And one of the most interesting things I came across
while prepping for this episode was the way human observation
actually affects the behavior of light. All right, well, I
(03:55):
think this pretty complicated, so why don't you break it
down a little. Well. When quantum theory became all the
rage in the twentieth century, scientists started noticing something super weird.
They found that when they use special equipment to pinpoint
the location of photons. These tiny bits of matter always
behaved as particles. For example, they could pass through one
tiny hole or another in a barrier, but not through
(04:15):
both holes at once. All right, so far, so good,
and particles do what particles do that. I don't think
there's anything weird about that, right, But the scientists also
discovered that when they didn't try to determine the exact
location of each photon, the photons behaved as waves instead
of particles. So the photons were then able to pass
through both tiny holes in a barrier at the same time.
And that's something that only waves can do, not particles. Okay, alright,
(04:38):
I spoke through soon. That's really weird. And so you're
saying that light, photons and other sub atomic matter act
like particles, you know, when they know we're watching, and
then like waves when they know we aren't looking. Yeah,
it's something like that. So obviously the photons themselves aren't
aware of us watching them, but they definitely seem to
act differently based on how closely we observe them. And
the best explanation, at least according to most physicists, is
(05:01):
that when we look closely, our brains halt the wave
patterns so that we can see the photon in a
certain place as a particle. It just makes us feel
better that way. That's really insane, all right. So where
does that leave us? Does light exists as a wave
or as tiny bits of almost invisible matter? Yeah, it's both.
So Bob Berman sums up the paradox this way, and
I'm going to quote him here. He says, just a
(05:22):
century ago, the local realism mindset of science and even
common sense, held that all objects, including atoms and photons,
have an existence independent of our observation of them. But
that's been replaced by a more modern view that our
observation itself is necessary for the very existence of a
photon or an electron. A spooky prospect, kidding. Yeah, So,
(05:43):
he continues, it possessed no real existence as an actual
photon or electron or whatever it was. Rather, it's observed
existence is it's only existence. The observation establishes reality, nothing
else is certain. Oh that's pretty trippy. Yeah, the stuff
feels so philosophical, and especially when you go from a
micro perspective to a macro one, because just like with photons,
(06:05):
the color and brightness of light doesn't exist outside the
experience of the observer. We only see light as a
certain color because of how it stimulates the cones in
our eyes and how our brain interprets those signals. Well,
that's a good point, but it's also kind of a
terrifying I mean, it means the external world is really
just as invisible as a UV ray, because outside of
human observation, there is no color or brightness. It's just
(06:27):
this mix of different invisible energy pulses. Actually, by the way,
that this is off topic, but did you read about
the women that supposedly have four cones in their eyes
instead of three, and as a result, they can see
hundreds of millions of color. That's a wild Yeah, they're
called tetra chromats. But baby, we're clinging too tightly to
the human experience that you know. I actually did some
(06:48):
digging to see if there were any animals whose vision
best oars in terms of light perception, and it turns
out there quite a few that put the invisible spectrum
to pretty good use. Awesome, so give me the low down. Well,
one case where plenty of animals have a speed is
the ability to perceive ultra violet light. The invisible UV
radiation is all around us, and while it's useful for
getting a golden tan, it's also a menace because exposure
(07:11):
to it can lead to melanoma and other illnesses. But
that hasn't stopped some animals from making the most of
UV light. There's some species of birds that have plumage
that you know, to our eyes look the same between
males and females. But if your vision allows you to
see the UV range like those birds are able to
see it, you know you'd be able to make out
the uvy markings that distinguish them. So those markings make
(07:32):
it easier for the birds to find a met definitely,
but that's actually only part of it. Some mother birds
determine which chicks to feed based on how much UV
light you know their heads reflect. For whatever reason, the
heartier birds tend to have a shinier crest than their
weaker siblings, so when the mama bird has limited food
to share, she'll go with whomever has the most shine.
There's also the fact that urine and feces of mice
(07:54):
and other small prey are visible in the ultra violet range,
so birds that are sensitive to UV light can use
these traces to track their prey, even in a place
where everything is uniform in color, you know, like a
green field or something like that. But you know, birds
aren't the only ones that can do this. You have
rodents and bats and even some marsupials that can see
UV light for similar reasons. So I actually think I
(08:17):
read something about butterflies also having great V perception, and
I think they use it to identify which flowers are
currently producing nectar based on the color of the petals
or something. Well, yeah, I'm glad you mentioned that, because
butterflies with a high sensitivity light are often considered to
have the widest visual range of any form of wildlife.
It's crazy the invisible world might be the most visible
(08:37):
to butterflies of all things. But before we move on,
there's one last animal I want to talk about, and
that's the reindeer. So I'm sure there's a Rudolph joke
in here somewhere, but not telling reindeer can see UV risk. Well,
it sounds strange at first, but reindeer of evolved to
take full advantage of the ultraviolet range, and they're not
the only ones. There are other Arctic mammals who make
(08:59):
their homes at the Earth's poles, and they have to
deal with much higher levels of UV light. Yeah, the
thinning ozone layer doesn't block as many rays as it
used to, especially in those upper latitudes. Yeah, exactly. So
there was this study out of the University College of
London and the University of Tromso in Norway, and they
found evidence that not only a reindeer resistant eye damage
from intense UV rays, they're also able to see UV
(09:22):
light and this helps them find food and avoid predators.
And in the winter, reindeer primarily do two things. They
eat lichen and they try to avoid being eaten by wolves.
And wouldn't you know it, lichen and the fur of
wolves both absorb UV light. So because snowy landscape strongly
have reflect UV rays, you got reindeer that can spot
lichen and wolves with ease. Yeah that's really cool, And well,
(09:45):
I think you and I could nerd out on reindeer
facts for a while, Like how Norwegian scientists wanted to
get closer to reindeers so they could study them better,
so they wore polar bear costumes and did that work? No,
not at all, Like it's scared off the reindeer. But
they also wrote a a scientific paper on reindeers reactions
to costumes, and we're hoping to redo the study with
better costumes, like like a clown costume. I like how
(10:07):
they just went off track there, Like that didn't work,
So let's just do costumes. How about clowns? How about
police officers? Science is great, but what I was saying
was I think we should shift the topic a little.
All right, well, what do you what do you want
to talk about? Secret messages? So last year a group
of scientists and friends developed a special kind of paper
that can carry secret messages. It looks just like plain
old paper, but you can use different wavelengths of UV
(10:29):
light to read, write, or even erase the messages that
can't be seen invisible light. So how does that work?
So apparently the paper has this special kind of molecule
bonded to its cellulose fibers that reacts and turns fluorescent
when exposed to UV light. The idea is you can
write messages on the paper using a stencil to produce
dark and bright areas that react differently under the UV lamp.
But the really cool thing is that the process is
(10:52):
completely reversible. You can expose the used paper to a
shorter wavelength of UV light that erases the message completely,
and that way paper can be used over and over.
I mean, it is kind of cool, but what's the
advantage over you know, the disappearing reappearing and visible length
that our kids play with and stuff like that. So
why is this better than that? So not only are
the messages on this paper undetectable under visible light, they
(11:15):
also can't be dissolved with other chemicals. So it's the
super useful tool in anti counterfeiting and tracking operations. A
good job, France, you know. I actually want to dive
into some of the historical obsession with invisibility and the
ridiculous potions humans used to make. But before we do that,
how about we check in with Bob Burman and see
if he can tell us a little about the cool
properties of light and how humans have managed to turn
(11:37):
something invisible to our advantage. So in this episode on
All Things Invisible, we've been talking a little bit about
this great book, Zapped, and we're really lucky to have
one America's top astronomy writers on with us and the
author of this book. It's Zapped from infrared to X rays.
The Curious History of invisible Light. Bob Berman, welcome to
(11:59):
Part time Genius. Well, thank you, great to be here.
All right, well, let's just start with the basics. So
can you explain to us where light comes from. Well,
all light, except for gamma rays, comes from one source only,
and that is atoms. If the atom gets excited in
any way, electricity, collisions, anything can may be excited, madam,
(12:19):
So that the electrons or in the case of hydraten
it's only got one electron, jumps to a higher orbit
because it's excited, it really doesn't like to be there.
So in a fraction of a second, it'll tumble down
closer to its nucleus, and that is what causes any
kind of light. And the distance that it tumbles down
(12:40):
determines the color of the light and therefore whether it's
visible or invisible. So, I know you talk about this
in your book, But what did ancient people think about
light and were they aware of invisible light? They felt
about light as at first something that comes from the eye,
and then later on as an interaction between a beam
(13:03):
from the eye and external objects. So they got it
wrong for a long time. They realized that it involves
something with a very fast speed, but nothing more than that.
And nobody foresaw invisible light until the time of the
Renaissance of the Middle Ages. It was one of those
things that no wise person or Greek philosopher, or scientists
(13:28):
or religious order, nobody came up with the idea that
there might be kinds of light out there that our
eyes can't see well. In the Renaissance, as you mentioned,
you know, with this idea of invisible light being a possibility,
how did this start to be discovered? Well, it's really
William Herschel who found the first kind. He projected sunlight
(13:48):
through a prism piece of cut glass onto a tabletop,
so you had the whole rainbow of colors. And then
he put a thermometer in each color, and he had
other bmometers on the side in the darkness to act
as controls. And so he noticed that when the thermometer
was in the blue or the green part of the spectrum,
(14:09):
the temperature went up very little, in the yellow it
went up more, and the red it went up still more.
But then he took a break, and when he came
back some minutes later, the sun had moved across the sky.
So the spectrum on the table had shifted, and now
his thermometer on the table was no longer in the
(14:30):
visible light instead of was sitting in a spot of
darkness outside of the spectrum, just beyond the red end
of the spectrum. And he looked down on it, and
now that thermometer was crazy. It was had It was
registering much more heat than any color did. And so
he repeated this and he realized that the blank spot
(14:52):
beyond the red part of the spectrum was heat, was
producing more heat while he realized it had to be
an invisible kind of light that was creating the heat,
and he called these calorific rays. Later on we came
to call it infrared. So that was the first kind
of invisible light ever discovered. Wow. Wow. And you also
(15:14):
talked in the book about the discovery of X rays
and I'm curious what the you know, the public response
was to this discovery. Well, X rays, Yeah, that changed
the world too. That was Renkin, and he was boy.
He had fame and he would have had fortune too
if he had patented it, but he didn't. Generously just
(15:34):
allowed the world to use it, and almost right away
people realized the value in medicine that you could use
X rays and find a bullet, wear a bullet was
in my body for someone who had been shot, or
where broken bones were broken. And but nobody knew at
the time that X rays also had a dark side,
(15:54):
that it could produce harm as well as benefits. What
new opportunities for the use of invisible light are the
horizon and things like medicine or technology or culture, well
everywhere you know, we use that more than visible light
these days. Everybody knows about microwaves and used in for
not just our ovens, but for broadcasting on the GPS
(16:17):
signals that come down to us from the radio part
of the spectrum. Really the microwave part of the spectrum.
So whenever we use our GPS in our cars, or
when when we're on a camping trip, or use our
cell phones, those are all parts of the radio spectrum.
And then we know about the infrared. We use heat laps,
we use garage door openers, that are they're using infrared
(16:41):
and ultra violet. That's boy, that's the one with the
two edged sword. Ultra Violet is both the most dangerous
form and the most valuable for our health. And what
makes UV rays so harmful to us. Well, they're the
beginning of the part of the spectrum that has the
power to ionize and others to strip electrons from atoms
(17:04):
and therefore to change genes, that change chromosomes, to alter DNA,
and that could give rise to cancer, and it does.
The eight thousand or so melanoma deaths per year. Skin
cancer are caused by generally too much UV, usually from
from from a bad sudden burn in our youth. And uh,
(17:29):
and that's why people nowadays know that they should be
putting on sunscreen and wearing hats and stuff like that.
But bad thing has happened from that too, in that
we've now blocked so much of the UV. That's strange
things are happening to our bodies that that most even
(17:50):
doctors are not aware of, although many are like like, like,
what do you do? Have some examples of this? Yeah, yeah,
and this is started. If I could give just a
bit of background, There was a time, of course, when
we were an agricultural society and we were out of
doors a lot, and we got plenty of sunlight and
therefore plenty of ultra violet, which is a few percent
(18:12):
of the sunlight and stimulates our bodies to produce U
v a vitamin D very quickly. That V induced vitamin
D is such a avalanchingly fast process that we get
more UV from twenty minutes in the strong sunlight, and
then you would from drinking two hundred glasses of milk.
(18:34):
So somehow our bodies want lots of vitamin D production
from UV. It's a natural thing. But as we moved
indoors to be a manufacturing society, and then starting in
the fifties and sixties, had air conditioning so that we
didn't have to open windows, and glass blocks UV, and
(18:55):
so it blocks the vitamin D production on our skin.
And then worst of all, this is something that the
Vitamin D Council talks about a lot, because the doctors there,
like John Cannell like are really getting frustrated with the
fact that we've turned into kind of a race of
of of mold people where we're blocking the sun entirely
(19:18):
and not getting enough sunlight. They see it that it
wasn't that many decades ago. The kids after school. Of course,
during school they're not getting any UV and therefore not
producing any vitamin D. But after school kids used to
play outdoors and parents used to say yeah, come back
at dinner time, and between they be out doing whatever
in the playground or climbing trees. And then that changed.
(19:41):
So their UV levels in their and their blood has
dropped to a really, really low level. So what does
this do is it turns out that UV is one
of the strongest prevent ers of cancer. It stops cancers
from growing, so when they're tiny, pre detectable tumors, they
(20:01):
don't get any bigger. This year, for example, it was
found that pancreatic cancer is prevented by by adequate vitamin
D triggered by ultra violet light. So there are a
lot of health benefits also psychological benefits in terms of
(20:22):
treatment for depression and and things like that. If you
get enough sunlight induced h vitamin D, it's hard to
strike that strike that perfect balance. No, you're so right.
At the same time, you don't want to burn. So
the people like Dr Cavill in the Vitamin D Council,
(20:43):
they say that we should get as much sun as
we can without burning, because everybody is so different and
how much sun they can handle before they start to burn.
You know, blue eyed blonde people tend to burn faster
and camp shouldn't get as much. Well, there are a
thousand other questions we could ask. Is this such a
(21:05):
fascinating book. I hope all of our listeners will check
out zapp. But Bob, thanks so much for joining us
on Part Time Genius. It's been a pleasure. Thanks so much.
(21:26):
You're listening to Part Time Genius and we're talking about
the peculiar allure of turning invisible, So mego. We mentioned
at the top of the show that humans have been
obsessed with the idea of invisibility from millennia, so I
thought it might be fun to take a look at
some of the weirdest attempts to go invisible that people
have tried all over the years. Yeah, so I'm definitely gay.
I spent some time looking up medieval recipes and spells
(21:46):
to turn yourself invisible, and as you might guess, they're insane.
So one of my favorites is from the Ashmole, which
is this anonymous fifteenth century manuscript that collected over a
hundred eighty magical and non magical recipes in English and Latin.
So this is the invisibility spell. It goes if you
wish to be invisible. Take a dead dog and bury
(22:08):
it and plant a bean plant over it, and place
one in your mouth, and without a doubt, you'll be invisible.
That that's it. It's simple. It's like one of these
great invisibility life hacks. But but don't worry. If you're
fresh out of dead dogs or beans, there's another suggestion
for you. Um this is also from the Middle Ages.
Grind up an owl's eye with the ball of beetle
(22:29):
dung and some olive oil and rub it all over
your body. I like the addition of the olive oil,
like weird stuff, and you know, just put some olive
oil in there that I think I'd rather eat the
dead dog being So why do they all have to
be so gross? So most invisibility charms that ties to
a cult practices so they tend to feature nasty ingredients
like the ivan a for a heart of a bat
or whatever. And one of them actually calls for the
(22:50):
head of someone who committed suicide but stuffed with fava beans. God,
it's hard to imagine why any of these ingredients were
picked to be the ones that would turn you invisible.
But I don't know, and think about it. Might have
something to do with our desire for power, which seems
to be at the root of man's continuing quest for invisibility.
I mean, we have stories going all the way back
to antiquity that point to the dark side of going invisible. Yeah.
(23:12):
So there are all kinds of myths and folk legends
that warn about the corrupting power invisibility and how it
can lead even the most pure of heart heroes into
recklessness or voyeurism. And well, you know, these commonalities between
fables from different cultures. I find these fascinating. In this case.
They seem to suggest that we all know invisibility as
a power that we probably shouldn't have, and you know,
(23:34):
it doesn't stop us from wanting it though. And in fact,
the top two superpowers that people always cite is the
ones they'd most like to have, are the ability to
fly and the power to turn invisible. Yeah. So both
of those provide the user a crazy amount of freedom,
and maybe that's why we find them appealing. You know,
that could definitely be the case. But in keeping with
the shady side of invisibility we've been talking about, there
(23:55):
there might be another explanation, and I couldn't find an
actual psychological study of this, but there is some speculation
about what the choice between flight and invisibility says about
a person. William Barry is this psychotherapist and professor at
Florida International University. He suggests that people who opt to
go invisible are embracing their dark side, you know, the
(24:15):
side of themselves that they typically don't like to acknowledge
as being part of them. So this is the side
of your psyche where all your most shameful thoughts and
desires dwell. According to Barry, quote, many of those who
choose invisibility do so to hear what others say about
them when they aren't around, or to spy on others,
or to procure things that they don't have the money
to pay for. It's easy to see how this relates
(24:37):
to the dark side. Yeah, it really is, especially when
you compare it to choosing flight, which is mostly appealing
as this form of fast travel or experiencing this different sensation,
but it doesn't seem to have any of the darker edge,
right and you know. Barry found that people who choose
power of flight generally see it as a way to
add excitement or fulfillment to their lives. Whether that's from
you know, maybe rescuing people from burning buildings or just
(24:59):
zipping across the world to have dinner in Italy, or
you know, something like that, which is interesting. You know,
there's another commonality between invisibility fables that we should probably
talk about, all right, and what's that invisibility cloaks. So
ancient Greek myths described caps and cloaks with magical properties
that made the were invisible to other mortal men, and
from their invisibility, cloaks have popped up in everything from
(25:21):
Welsh and Germanic folklore to modern day pop culture. Of course,
and I'm guessing being a big fan, you're thinking of
Harry Potter definitely, So Harry Potter is never far from
my mind. But scientists have been hard at work on
cloaking devices for a while now, things that can mask
or completely hide an object or a person from sight.
And sometimes they're more successful than others. But all of
(25:42):
the most promising ones involves something called meta materials, and
it's just you know, some kind of super science cloth
or something more or less. So meta materials are basically
a kind of material that's engineered to have properties that
that don't occur in nature, and in this case, it's
a light bending property that manipulates by So the reason
objects are visible to our eyes at all is because
(26:04):
objects distort light waves based on their shapes. But when
the light from an object reaches our eyes, we see
the object by recognizing those distortions. Alright, so meta materials
they somehow counteract this or so. The idea is that
the meta material forms a kind of shell around the object,
or a cloak, so the light rays bends smoothly around
the meta material and recombined on the other side. And
(26:27):
one helpful example I came across is that it's kind
of like water flowing around a rock and a stream.
I viewer on the far side wouldn't see anything unusual,
but both the meta materials shield and object in its
center would be completely invisible to him. It would look
like the lights bouncing off a smooth surface, which is
pretty cool. But I don't know, I have the same thing.
I've read so many headlines over the last few years
(26:48):
that claim we're this much closer to Harry Potter like
invisibility cloak, And you know, there are definitely some similarities
to what you're describing, but it's hardly a one to want.
I mean, I mean, natural materials get their special properties
from the arrangement of atoms, and there's no way what's
going on with these meta materials is the same thing. Yeah,
that's true. And these cloaking devices are more like chunky
(27:09):
rings and pyramids that fit over a stationary object right now,
rather than any sort of sleek piece of fabric. But
the technology is advancing pretty quickly. Well, I'm glad to
know that we're on our way towards that. But why
don't we break for a little quiz? Alright, So today's
show us about invisibility. We decided to bring on to
(27:31):
Seattle based artists who produced the delightful art series that
only shows up when it rains. Welcome to the show,
Peregon Church and Zach Fisher. Thank you great to be here.
I am so excited to have you on. And and
for you listeners who aren't familiar with rain Works, you
should definitely check out the photo gallery at www dot
rain dot works because it's fantastic. So can you tell
(27:53):
us a little bit about how you came up with
this idea of making invisible artwork that only shows up
in the rain. I love thinking of ways to use
materials that already exists in ways that they shouldn't be used.
And I came across this stuff called super hydrophobic coatings. Basically,
when you put it on the surface, it keeps it
from getting wet, and I thought, wow, that's super cool.
(28:16):
You're watching all this water roll off these clothes and
shoes and whatever. What if you put it on something
that change color when it got wet, like concrete, and
so you since it's a spray on the thing, you
could spray it through a stencil on the concrete, and
as long as it was invisible and dry, you can
create art that was only visible when the surface is wet.
Would you tell our listeners a little bit about some
(28:36):
of the designs you do and how you make them interactive? Sure,
we like to do things that are positive, things that
don't make someone stay better. That's are really one of
the big motivations behind it. Because in Seattle and the
Pacific Northwestern general people tend to suffer from sad seasonal
effect of disorders. The skuys are gray and it's dreary
and wet all the time. So we figured we could
(28:58):
take that thing that causes the jurius the rain and
use it to make people smile. We did a lock
mass monster at a at a dock out in over
a lake here in Seattle Green Lake so that people
could stumble upon the monster while they were out on
rainy days. We do games. Sometimes, we've done like it
Don't Touch the Lava game. Um. We've done like nostalgic
(29:22):
references to like characters that we love as like when
we were kids. So like we've done like a Peter
Pan rainwork and like Calvin and Hobbs rain work. Basically
just whatever we think would like cheer someone up or
make them smile or make them think when they see
it it's funny. I mean even hearing the examples makes
you smile. That's pretty great. And you've now turned this
(29:43):
into a business. So what are the best applications of
your rain works? And you know that you've seen in
the wild. Now, oh man, we've seen so many some
all over the world. Some people have done like promposals
or actual wedding proposals with them. We've seen people use
public sountains to make like dolphins that appear. That's awesome. Yeah,
(30:04):
there was one just like a day or two ago
where they coated a canvas with it, then through water
balloons with like water based paint in them, through do
a gender reveal right back, that was what that was. Yeah, Yeah,
it's that kind of worked a little differently because our
spray doesn't repel paint, but it like reacted with it
in a certain way, so it does kind of make
(30:25):
the letters pop, but like not in the way you expect.
It's really interesting to see like a new application for it,
and that's really been the coolest thing is like just
since this started, it's really taken off just all around
the world, and we get like no one's popping up
in like Denmark and like Taiwan and like Armenia. Does
having worked on this project make you look forward to
(30:47):
rainy days? Like do you sit on benches waiting for
people to interact with the art? Oh? Absolutely. It has
completely changed our perspective on rainy days. And one of
our favorite things to hear when we tell people about
the project is them the words coming out of their mouths,
oh my gosh, I can't wait till it rains. Now,
like that means the world to us. We've become so
(31:10):
hyper sensitive to it that every time it starts to
rain or like the forecast predicts range like were like
on the edge of our sieves, like we're preparing, we're
making rain work. Our our whole work as well depends
on the weather. For sure, we'll tell us a little
bit about your connection with the Awesome Foundation. Sure. When
(31:30):
I had this idea, it was just an idea, like
on a note in my phone for a long time,
but it was one of one of my favorites, and
I started mentioning it to people and eventually mentioned it
to a friend in Seattle who was part of the
Seattle chapter of the Awesome Foundation. For anyone doesn't know,
the Awesome Foundation is an organization that every month it's
(31:54):
one dollars the person with a cool idea or an
awesome idea, as they put it, No, it's needs attached.
So I submitted this rain activated our idea, but we're
not called rain works to the Austin Foundation, and they
accepted it, and that was what really gave it the
first push. All right, Well, I thought we should play
a little game with these guys, and Mango, you came
(32:16):
up with one that's appropriate from what what game are
we playing with? A Peregrine and Zach. It's called I'm
Only Have You in It rains all right. We love
your Rainy Day project, and we figured we'd give you
a quiz where all the answers involved rain and you
can work together on this. So you guys ready, you're ready? Alright?
He got five questions for you, all right. Number One,
Gene Kelly had a one hundred and three degree fever
(32:38):
when he danced the big number in this rainy movie.
What classic film are we talking about? One? Number two,
Prince's manager questioned the decision to put When Doves Cry
in this movie slash album because the song didn't have
a baseline and he didn't think it would be a hit.
What Prince movie are we talking about? Purple Yes? All right?
(33:01):
Number three? All these pop culture references. I'm depending on
your's action. He's really pulling through, alright. Number three. During
the filming of this award winning movie, both Tom Cruise
and Dustin Hoffman thought the flick would be a clunker.
The whole time. They referred to it as two schmucks
in a car. What movie are we talking about? Wait?
(33:23):
I got this one, Raymond. Alright, with the big answer
here we go number four. Before this actor won the
role of Dwight Shrut on the Office seth Rogan had
auditioned for the role. Who are we talking about Wilson? Yes,
they both got that one, all right. The last question
see if you can get the perfect score number five.
(33:44):
This song, written by Paul Schaeffer and performed by the
Weather Girls, was intended to be a gay anthem, much
like Y M c A. You know the name of
the song, it's man. Yes, all right? How did they do? Mango?
Our howls when astounding five for five, which means we'll
be sending them our top prize, a handwritten note to
their mom or boss, singing their praises congratulations, m thanks
(34:09):
so much. Yeah, that's awesome. Listeners, please check out rain
dot Works when you get a second, and thank you
guys so much for all the work you do and
for putting smiles on so many faces having us. Okay, well,
(34:37):
so we talked about fictional invisibility cloaks as well as
the closest things. We have two real life ones. But
there's one more thing I want to talk about, and
it's the psychological sort. It's kind of a psychological invisibility
quote I don't even know how that would work. Is
like a helmet that would block your brain waves or
something like that. Yeah, that's a good guess, but no,
nothing like that. I'm actually talking about the great study
(34:58):
I came across about a I'm not called it invisibility
cloak illusion, and that's the name researchers at Yale University
came up with for our mistaken belief that we observe
others way more than others observe us. All Right, so
this is kind of like us pretending that maybe we're
under invisibility cloaks when we're out in public, if we're
grocery shopping or walking our dogs or something like that,
exactly pretty much any time we're in public, really, So
(35:21):
the team describes it this way, and they're abstract quote,
whether at a coffee shop, in a waiting room, or
riding the bus, people frequently observe the other people around them,
yet they fail to realize how much other people engage
in the same behavior, and that they therefore also are
being observed. Because it's logically impossible that people on average
(35:41):
are the subjects of observation more than they are objects
of it. The belief that one watches others more than
one is watched is an illusion that's pretty wild. I mean,
we feel like we're invisible, when the fact that we
observe others should tell us just the opposite of this.
And I really can't understand why we make this silly mistake,
because it's just that we're egomany acts, and you know,
we think we're the observant person and the only observant
(36:03):
person in a room. Yeah, that's definitely part of it.
But at least there's a good reason why we think
that way. And why is that? Well, the researchers at
Yale concluded that social norms compel our neighbors to pretend
to be busy with something else if it looks like
we might catch them watching us. All right, so we've
secretly scoped out the competition at a job interview, or
glanced around the waiting room and a doctor's office, and
(36:24):
just in case we need an alibi, we have a
magazine or something like that. It's funny that we all
assume we're the only ones who do this, though, right, so,
when it's actually so widespread and phenomena that it even
has its own name, researchers call it civil and attention.
I kind of like that, yeah, But my favorite part
of the study is this line from the conclusion, however
irresistible the sensation of being invisible, maybe it is not
(36:47):
to be trusted. That sounds exactly right, and it actually
makes it me think of this this other study I
read on the logic of the game Peekaboo. Apparently it's
this great display of the kind of nonsensical logic that
most kids share, namely the idea that you can make
yourself invisible by just covering your own eyes. So the
study was what like scientists rounded up a bunch of
toddlers and had this epic peekaboo session, Not exactly, but
(37:10):
but kind of. So the researchers at the University of
Cambridge had a group of three and four year olds
where I'm asked, and then they asked them whether they
could be seen by researchers or if they were invisible
to them. Then they asked the kids whether the researchers
would be able to see adults if those adults were
wearing eyemask like their's, and unsurprisingly, nearly all the kids
said they were hidden from view while their eyes were covered,
(37:33):
and most of them actually thought the imask would make
the adults invisible too, which is super cute. But did
the researchers have any ideas for why almost every child
subscribes to that weird logic. Well, actually, here's where things
get really interesting. And because when kids had their eyes covered,
they felt invisible, which fair enough, I mean, I think
we've all heard that before. But the researchers started to
(37:53):
press them on what invisibility meant, and surprisingly, the kids
conceded that their bodies weren't actually hidden it all all
in the sixth so they admitted their bodies could still
be seen even when their eyes were covered. So what
do they mean by invisible? So that's the weirdest part
and where this gets a little deep here. So the
implication was that the kids felt it was their true
self that was being hidden from view. So basically, they
(38:15):
were saying, I know, you can still see my arms
and my legs and all that when my eyes are closed,
but you can't see me, which is which is pretty existential,
you know, I know. It's it's like the children share
some natural distinction between you know, the physical body and
the metaphysical self. And I just find this stuff fascinating.
And you know, because most adults tend to think of
(38:36):
their consciousness and their body being joined together in some way,
and studies like this suggests that perception might be something
we only adopt or maybe decide on later in life. Yeah,
that's especially interesting when you think about how people always
say the eyes of the window to the soul, or
that eye contact Foster's understanding. I mean, in some ways,
covering your eyes really is like withdrawing yourself from the
(38:58):
world and making yourself invisible. Alright, well, Mango, you need
to keep those eyes open because there's only one thing
you can't hide from the PGG fact off exactly. All right,
here's something I hadn't thought about. Any lightbeam weapon you
(39:21):
see in the movies, from photon torpedoes to invisible rays,
they're all things you won't see coming so anytime as
sci fi heroes and a jet dodging those rays. None
of that's possible. You know that some of the things
you see in movies you just ruined all movies did so.
I want to know a figure who's basically become invisible
Jeremiah Dummer. Most people know. Yale University is named for
(39:42):
Elihu Yale, but Dumber probably did more for the early
university in terms of securing funds and building its reputation.
The problem is, Dumber College isn't a great name. Well,
Reindeer are good at spotting polar bears, Cameras aren't, so
when scientists decided to use infrared cameras to locate the bears,
they were stunned because polar bears are basically invisible to
infrared cameras too. While cameras can pick up the heat
(40:05):
off their nose and their breath, their blubber basically does
such a good job of trapping the heat within that
their fur is essentially the same temperature as all the
snow around it. So despite all the safety features and
cars with backup cameras and beeping sensors, people still back
up into lampos. So researchers at Kyo University in Japan
have come up with back seats that actually turned transparent
(40:27):
when you back up. Basically, it's a backup camera that
projects on the seats, but it does the trick of
seeming transparent and of course making the children sitting in
those seats disappear as another matter, definitely all right, here's
a fun one about not being seen. A building supervisor
in Spain skipped work for six years and kept collecting
his salary. You know the only reason he got caught.
(40:47):
People got suspicious when he won an award for twenty
years of loyal service. In two thousand six, Magician David
Copperfield and his two assistants were walking down the street
when mugger's approached and demanded all their money, and all
the assistants forked over plane tickets, cell phones, and over
five dollars in cash. Copperfield used sleight of hand to
show the gun wielding robbers that his pockets were empty.
(41:09):
He reperformed the trick at the police station and wow
the officers, showing them he actually had a passport and
lost with cash on him the whole time. I know
he's such a performer, but he did help catch the
bad guys and I kind of love it all right. Well,
in that case, I'm gonna have to give you today's
championship felt. So that's it for today's episode. Thanks so
much for listening, Thanks again for listening. Part Time Genius
(41:44):
is a production of how Stuff Works and wouldn't be
possible without several brilliant people who do the important things
we couldn't even begin to understand. Christa McNeil does the
editing thing. Noel Brown made the theme song and does
the MIXI MIXI sound thing. Jerry Rowland does the exact
producer thing. Gave Bluesiers our lead researcher, with support from
the Research Army, including Austin Thompson, Nolan Brown and Lucas
Adams and Eve Jeff Cook gets the show to your ears.
(42:07):
Good job, Eves. If you like what you heard, we
hope you'll subscribe, And if you really really like what
you've heard, maybe you could leave a good review for us.
Do we do? We forget Jason? Jason who
Guess what, mango, what's that? Will? I was reading this
old story about a bank robbery that happened in so
this guy walks into two banks, one after the other.
He has no mask and no face cover. I mean,
it didn't seem like he was trying to hide himself.
And he gets caught on camera pretty clearly, and so
obviously he's apprehended not long after that. But the weird
(00:21):
thing is when the cops come fro him, he was
totally baffled. Well, he kept saying, I was wearing the juice.
The juice, Well, apparently he'd poured lemon juice all over
his face because he knew it could be used as
this invisible ink for writing. And the poor guy, he
was really bewildered because he said he tested it out,
and the cops pressed him for details, and he said
(00:41):
the lemon juice had gotten in his eyes the first
time when he poured it all over his face, and
then he took a selfie to see if it had worked.
And the combination of squinting and not being accustomed to
taking his own photo, I mean, this this was well,
it made him take a photograph that he wasn't in
and he just believed that he was invisible. Oh no,
I know you almost feel bad for the guy, but
(01:03):
you know, reading up on his invisible face juice made
me wonder what is the science of invisibility and what
are some of the things going on that we can't see?
And where is my invisibility cloak? So let's dive in.
(01:28):
Y Hey, their podcast listeners, Welcome to Part Time Genius.
I'm Will Pearson and as always I'm joined by my
good friend Man Guesh, I'll Ticketer and over there on
the other side of the glass with the biggest smile
that you can't see is Tristan McNeil, our producer, And
on today's show, we're taking a WorldWind tour of our
(01:49):
invisible world and trying to get a better grasp of
all things unseen. You know, the idea of invisibility is
fascinated mankind for thousands of years. It's parts of our
myths and our folklore and our pop culture and you know,
even our psychology. Of course, there are lots of different
kinds of invisibility. So this will be a super fun
Hodgepodge episode where we cover as much as possible. We'll
(02:10):
talk to a couple of insightful authors who have devoted
years of study to stuff we can't see. So who
do we have on the line today, Mango, Today we're
talking to Bob Berman, one of America's top astronomy writers
and author of a brand new book about the curious
history of invisible light. It's called Zapped, and it's incredible
and we'll have some wonderful quizzes along the way as usual.
All right, So, in honor of Bob's new book, I
(02:30):
want to dive straight into the science and talk about light,
and more specifically invisible light. You know, obviously there are
large portions of the electromagnetic spectrum that we have no
trouble observing, but there's also a huge part that's totally
invisible to us. That's the part that includes things like
ultra violet light and for red light, radio waves, microwaves,
X rays, gamma raves, you know, all that good stuff. Yeah.
(02:52):
I mean, I always knew there were parts of the
spectrum beyond our range of vision, just like you know
there's sounds outside the limits of human hearing. But reading
Bob's book put the vastness of light in a completely
new perspective for me, and it really blew me away.
So Bourmon rights, there's more light in the universe than
anything else. So if you were to add up every
individual light photon in the cosmos, they would account for
(03:14):
nine point of everything there is. And those forms of
invisible light you listed off, that actually makes up the
vast majority of the light. I actually can't wrap my
head around that fact, but it seems unbelievable. But you know,
our eyes are designed to recognize only the Sun's most
abundant energy, so we really can only see the colors
(03:34):
that the Sun emits most strongly. And even though the
whole universe is light, the bulk of it, it's completely
invisible to us. We've actually figured out all kinds of
ingenious ways to measure and observe forms of invisible light.
And one of the most interesting things I came across
while prepping for this episode was the way human observation
actually affects the behavior of light. All right, well, I
(03:55):
think this pretty complicated, so why don't you break it
down a little. Well. When quantum theory became all the
rage in the twentieth century, scientists started noticing something super weird.
They found that when they use special equipment to pinpoint
the location of photons. These tiny bits of matter always
behaved as particles. For example, they could pass through one
tiny hole or another in a barrier, but not through
(04:15):
both holes at once. All right, so far, so good,
and particles do what particles do that. I don't think
there's anything weird about that, right, But the scientists also
discovered that when they didn't try to determine the exact
location of each photon, the photons behaved as waves instead
of particles. So the photons were then able to pass
through both tiny holes in a barrier at the same time.
And that's something that only waves can do, not particles. Okay, alright,
(04:38):
I spoke through soon. That's really weird. And so you're
saying that light, photons and other sub atomic matter act
like particles, you know, when they know we're watching, and
then like waves when they know we aren't looking. Yeah,
it's something like that. So obviously the photons themselves aren't
aware of us watching them, but they definitely seem to
act differently based on how closely we observe them. And
the best explanation, at least according to most physicists, is
(05:01):
that when we look closely, our brains halt the wave
patterns so that we can see the photon in a
certain place as a particle. It just makes us feel
better that way. That's really insane, all right. So where
does that leave us? Does light exists as a wave
or as tiny bits of almost invisible matter? Yeah, it's both.
So Bob Berman sums up the paradox this way, and
I'm going to quote him here. He says, just a
(05:22):
century ago, the local realism mindset of science and even
common sense, held that all objects, including atoms and photons,
have an existence independent of our observation of them. But
that's been replaced by a more modern view that our
observation itself is necessary for the very existence of a
photon or an electron. A spooky prospect, kidding. Yeah, So,
(05:43):
he continues, it possessed no real existence as an actual
photon or electron or whatever it was. Rather, it's observed
existence is it's only existence. The observation establishes reality, nothing
else is certain. Oh that's pretty trippy. Yeah, the stuff
feels so philosophical, and especially when you go from a
micro perspective to a macro one, because just like with photons,
(06:05):
the color and brightness of light doesn't exist outside the
experience of the observer. We only see light as a
certain color because of how it stimulates the cones in
our eyes and how our brain interprets those signals. Well,
that's a good point, but it's also kind of a
terrifying I mean, it means the external world is really
just as invisible as a UV ray, because outside of
human observation, there is no color or brightness. It's just
(06:27):
this mix of different invisible energy pulses. Actually, by the way,
that this is off topic, but did you read about
the women that supposedly have four cones in their eyes
instead of three, and as a result, they can see
hundreds of millions of color. That's a wild Yeah, they're
called tetra chromats. But baby, we're clinging too tightly to
the human experience that you know. I actually did some
(06:48):
digging to see if there were any animals whose vision
best oars in terms of light perception, and it turns
out there quite a few that put the invisible spectrum
to pretty good use. Awesome, so give me the low down. Well,
one case where plenty of animals have a speed is
the ability to perceive ultra violet light. The invisible UV
radiation is all around us, and while it's useful for
getting a golden tan, it's also a menace because exposure
(07:11):
to it can lead to melanoma and other illnesses. But
that hasn't stopped some animals from making the most of
UV light. There's some species of birds that have plumage
that you know, to our eyes look the same between
males and females. But if your vision allows you to
see the UV range like those birds are able to
see it, you know you'd be able to make out
the uvy markings that distinguish them. So those markings make
(07:32):
it easier for the birds to find a met definitely,
but that's actually only part of it. Some mother birds
determine which chicks to feed based on how much UV
light you know their heads reflect. For whatever reason, the
heartier birds tend to have a shinier crest than their
weaker siblings, so when the mama bird has limited food
to share, she'll go with whomever has the most shine.
There's also the fact that urine and feces of mice
(07:54):
and other small prey are visible in the ultra violet range,
so birds that are sensitive to UV light can use
these traces to track their prey, even in a place
where everything is uniform in color, you know, like a
green field or something like that. But you know, birds
aren't the only ones that can do this. You have
rodents and bats and even some marsupials that can see
UV light for similar reasons. So I actually think I
(08:17):
read something about butterflies also having great V perception, and
I think they use it to identify which flowers are
currently producing nectar based on the color of the petals
or something. Well, yeah, I'm glad you mentioned that, because
butterflies with a high sensitivity light are often considered to
have the widest visual range of any form of wildlife.
It's crazy the invisible world might be the most visible
(08:37):
to butterflies of all things. But before we move on,
there's one last animal I want to talk about, and
that's the reindeer. So I'm sure there's a Rudolph joke
in here somewhere, but not telling reindeer can see UV risk. Well,
it sounds strange at first, but reindeer of evolved to
take full advantage of the ultraviolet range, and they're not
the only ones. There are other Arctic mammals who make
(08:59):
their homes at the Earth's poles, and they have to
deal with much higher levels of UV light. Yeah, the
thinning ozone layer doesn't block as many rays as it
used to, especially in those upper latitudes. Yeah, exactly. So
there was this study out of the University College of
London and the University of Tromso in Norway, and they
found evidence that not only a reindeer resistant eye damage
from intense UV rays, they're also able to see UV
(09:22):
light and this helps them find food and avoid predators.
And in the winter, reindeer primarily do two things. They
eat lichen and they try to avoid being eaten by wolves.
And wouldn't you know it, lichen and the fur of
wolves both absorb UV light. So because snowy landscape strongly
have reflect UV rays, you got reindeer that can spot
lichen and wolves with ease. Yeah that's really cool, And well,
(09:45):
I think you and I could nerd out on reindeer
facts for a while, Like how Norwegian scientists wanted to
get closer to reindeers so they could study them better,
so they wore polar bear costumes and did that work? No,
not at all, Like it's scared off the reindeer. But
they also wrote a a scientific paper on reindeers reactions
to costumes, and we're hoping to redo the study with
better costumes, like like a clown costume. I like how
(10:07):
they just went off track there, Like that didn't work,
So let's just do costumes. How about clowns? How about
police officers? Science is great, but what I was saying
was I think we should shift the topic a little.
All right, well, what do you what do you want
to talk about? Secret messages? So last year a group
of scientists and friends developed a special kind of paper
that can carry secret messages. It looks just like plain
old paper, but you can use different wavelengths of UV
(10:29):
light to read, write, or even erase the messages that
can't be seen invisible light. So how does that work?
So apparently the paper has this special kind of molecule
bonded to its cellulose fibers that reacts and turns fluorescent
when exposed to UV light. The idea is you can
write messages on the paper using a stencil to produce
dark and bright areas that react differently under the UV lamp.
But the really cool thing is that the process is
(10:52):
completely reversible. You can expose the used paper to a
shorter wavelength of UV light that erases the message completely,
and that way paper can be used over and over.
I mean, it is kind of cool, but what's the
advantage over you know, the disappearing reappearing and visible length
that our kids play with and stuff like that. So
why is this better than that? So not only are
the messages on this paper undetectable under visible light, they
(11:15):
also can't be dissolved with other chemicals. So it's the
super useful tool in anti counterfeiting and tracking operations. A
good job, France, you know. I actually want to dive
into some of the historical obsession with invisibility and the
ridiculous potions humans used to make. But before we do that,
how about we check in with Bob Burman and see
if he can tell us a little about the cool
properties of light and how humans have managed to turn
(11:37):
something invisible to our advantage. So in this episode on
All Things Invisible, we've been talking a little bit about
this great book, Zapped, and we're really lucky to have
one America's top astronomy writers on with us and the
author of this book. It's Zapped from infrared to X rays.
The Curious History of invisible Light. Bob Berman, welcome to
(11:59):
Part time Genius. Well, thank you, great to be here.
All right, well, let's just start with the basics. So
can you explain to us where light comes from. Well,
all light, except for gamma rays, comes from one source only,
and that is atoms. If the atom gets excited in
any way, electricity, collisions, anything can may be excited, madam,
(12:19):
So that the electrons or in the case of hydraten
it's only got one electron, jumps to a higher orbit
because it's excited, it really doesn't like to be there.
So in a fraction of a second, it'll tumble down
closer to its nucleus, and that is what causes any
kind of light. And the distance that it tumbles down
(12:40):
determines the color of the light and therefore whether it's
visible or invisible. So, I know you talk about this
in your book, But what did ancient people think about
light and were they aware of invisible light? They felt
about light as at first something that comes from the eye,
and then later on as an interaction between a beam
(13:03):
from the eye and external objects. So they got it
wrong for a long time. They realized that it involves
something with a very fast speed, but nothing more than that.
And nobody foresaw invisible light until the time of the
Renaissance of the Middle Ages. It was one of those
things that no wise person or Greek philosopher, or scientists
(13:28):
or religious order, nobody came up with the idea that
there might be kinds of light out there that our
eyes can't see well. In the Renaissance, as you mentioned,
you know, with this idea of invisible light being a possibility,
how did this start to be discovered? Well, it's really
William Herschel who found the first kind. He projected sunlight
(13:48):
through a prism piece of cut glass onto a tabletop,
so you had the whole rainbow of colors. And then
he put a thermometer in each color, and he had
other bmometers on the side in the darkness to act
as controls. And so he noticed that when the thermometer
was in the blue or the green part of the spectrum,
(14:09):
the temperature went up very little, in the yellow it
went up more, and the red it went up still more.
But then he took a break, and when he came
back some minutes later, the sun had moved across the sky.
So the spectrum on the table had shifted, and now
his thermometer on the table was no longer in the
(14:30):
visible light instead of was sitting in a spot of
darkness outside of the spectrum, just beyond the red end
of the spectrum. And he looked down on it, and
now that thermometer was crazy. It was had It was
registering much more heat than any color did. And so
he repeated this and he realized that the blank spot
(14:52):
beyond the red part of the spectrum was heat, was
producing more heat while he realized it had to be
an invisible kind of light that was creating the heat,
and he called these calorific rays. Later on we came
to call it infrared. So that was the first kind
of invisible light ever discovered. Wow. Wow. And you also
(15:14):
talked in the book about the discovery of X rays
and I'm curious what the you know, the public response
was to this discovery. Well, X rays, Yeah, that changed
the world too. That was Renkin, and he was boy.
He had fame and he would have had fortune too
if he had patented it, but he didn't. Generously just
(15:34):
allowed the world to use it, and almost right away
people realized the value in medicine that you could use
X rays and find a bullet, wear a bullet was
in my body for someone who had been shot, or
where broken bones were broken. And but nobody knew at
the time that X rays also had a dark side,
(15:54):
that it could produce harm as well as benefits. What
new opportunities for the use of invisible light are the
horizon and things like medicine or technology or culture, well
everywhere you know, we use that more than visible light
these days. Everybody knows about microwaves and used in for
not just our ovens, but for broadcasting on the GPS
(16:17):
signals that come down to us from the radio part
of the spectrum. Really the microwave part of the spectrum.
So whenever we use our GPS in our cars, or
when when we're on a camping trip, or use our
cell phones, those are all parts of the radio spectrum.
And then we know about the infrared. We use heat laps,
we use garage door openers, that are they're using infrared
(16:41):
and ultra violet. That's boy, that's the one with the
two edged sword. Ultra Violet is both the most dangerous
form and the most valuable for our health. And what
makes UV rays so harmful to us. Well, they're the
beginning of the part of the spectrum that has the
power to ionize and others to strip electrons from atoms
(17:04):
and therefore to change genes, that change chromosomes, to alter DNA,
and that could give rise to cancer, and it does.
The eight thousand or so melanoma deaths per year. Skin
cancer are caused by generally too much UV, usually from
from from a bad sudden burn in our youth. And uh,
(17:29):
and that's why people nowadays know that they should be
putting on sunscreen and wearing hats and stuff like that.
But bad thing has happened from that too, in that
we've now blocked so much of the UV. That's strange
things are happening to our bodies that that most even
(17:50):
doctors are not aware of, although many are like like, like,
what do you do? Have some examples of this? Yeah, yeah,
and this is started. If I could give just a
bit of background, There was a time, of course, when
we were an agricultural society and we were out of
doors a lot, and we got plenty of sunlight and
therefore plenty of ultra violet, which is a few percent
(18:12):
of the sunlight and stimulates our bodies to produce U
v a vitamin D very quickly. That V induced vitamin
D is such a avalanchingly fast process that we get
more UV from twenty minutes in the strong sunlight, and
then you would from drinking two hundred glasses of milk.
(18:34):
So somehow our bodies want lots of vitamin D production
from UV. It's a natural thing. But as we moved
indoors to be a manufacturing society, and then starting in
the fifties and sixties, had air conditioning so that we
didn't have to open windows, and glass blocks UV, and
(18:55):
so it blocks the vitamin D production on our skin.
And then worst of all, this is something that the
Vitamin D Council talks about a lot, because the doctors there,
like John Cannell like are really getting frustrated with the
fact that we've turned into kind of a race of
of of mold people where we're blocking the sun entirely
(19:18):
and not getting enough sunlight. They see it that it
wasn't that many decades ago. The kids after school. Of course,
during school they're not getting any UV and therefore not
producing any vitamin D. But after school kids used to
play outdoors and parents used to say yeah, come back
at dinner time, and between they be out doing whatever
in the playground or climbing trees. And then that changed.
(19:41):
So their UV levels in their and their blood has
dropped to a really, really low level. So what does
this do is it turns out that UV is one
of the strongest prevent ers of cancer. It stops cancers
from growing, so when they're tiny, pre detectable tumors, they
(20:01):
don't get any bigger. This year, for example, it was
found that pancreatic cancer is prevented by by adequate vitamin
D triggered by ultra violet light. So there are a
lot of health benefits also psychological benefits in terms of
(20:22):
treatment for depression and and things like that. If you
get enough sunlight induced h vitamin D, it's hard to
strike that strike that perfect balance. No, you're so right.
At the same time, you don't want to burn. So
the people like Dr Cavill in the Vitamin D Council,
(20:43):
they say that we should get as much sun as
we can without burning, because everybody is so different and
how much sun they can handle before they start to burn.
You know, blue eyed blonde people tend to burn faster
and camp shouldn't get as much. Well, there are a
thousand other questions we could ask. Is this such a
(21:05):
fascinating book. I hope all of our listeners will check
out zapp. But Bob, thanks so much for joining us
on Part Time Genius. It's been a pleasure. Thanks so much.
(21:26):
You're listening to Part Time Genius and we're talking about
the peculiar allure of turning invisible, So mego. We mentioned
at the top of the show that humans have been
obsessed with the idea of invisibility from millennia, so I
thought it might be fun to take a look at
some of the weirdest attempts to go invisible that people
have tried all over the years. Yeah, so I'm definitely gay.
I spent some time looking up medieval recipes and spells
(21:46):
to turn yourself invisible, and as you might guess, they're insane.
So one of my favorites is from the Ashmole, which
is this anonymous fifteenth century manuscript that collected over a
hundred eighty magical and non magical recipes in English and Latin.
So this is the invisibility spell. It goes if you
wish to be invisible. Take a dead dog and bury
(22:08):
it and plant a bean plant over it, and place
one in your mouth, and without a doubt, you'll be invisible.
That that's it. It's simple. It's like one of these
great invisibility life hacks. But but don't worry. If you're
fresh out of dead dogs or beans, there's another suggestion
for you. Um this is also from the Middle Ages.
Grind up an owl's eye with the ball of beetle
(22:29):
dung and some olive oil and rub it all over
your body. I like the addition of the olive oil,
like weird stuff, and you know, just put some olive
oil in there that I think I'd rather eat the
dead dog being So why do they all have to
be so gross? So most invisibility charms that ties to
a cult practices so they tend to feature nasty ingredients
like the ivan a for a heart of a bat
or whatever. And one of them actually calls for the
(22:50):
head of someone who committed suicide but stuffed with fava beans. God,
it's hard to imagine why any of these ingredients were
picked to be the ones that would turn you invisible.
But I don't know, and think about it. Might have
something to do with our desire for power, which seems
to be at the root of man's continuing quest for invisibility.
I mean, we have stories going all the way back
to antiquity that point to the dark side of going invisible. Yeah.
(23:12):
So there are all kinds of myths and folk legends
that warn about the corrupting power invisibility and how it
can lead even the most pure of heart heroes into
recklessness or voyeurism. And well, you know, these commonalities between
fables from different cultures. I find these fascinating. In this case.
They seem to suggest that we all know invisibility as
a power that we probably shouldn't have, and you know,
(23:34):
it doesn't stop us from wanting it though. And in fact,
the top two superpowers that people always cite is the
ones they'd most like to have, are the ability to
fly and the power to turn invisible. Yeah. So both
of those provide the user a crazy amount of freedom,
and maybe that's why we find them appealing. You know,
that could definitely be the case. But in keeping with
the shady side of invisibility we've been talking about, there
(23:55):
there might be another explanation, and I couldn't find an
actual psychological study of this, but there is some speculation
about what the choice between flight and invisibility says about
a person. William Barry is this psychotherapist and professor at
Florida International University. He suggests that people who opt to
go invisible are embracing their dark side, you know, the
(24:15):
side of themselves that they typically don't like to acknowledge
as being part of them. So this is the side
of your psyche where all your most shameful thoughts and
desires dwell. According to Barry, quote, many of those who
choose invisibility do so to hear what others say about
them when they aren't around, or to spy on others,
or to procure things that they don't have the money
to pay for. It's easy to see how this relates
(24:37):
to the dark side. Yeah, it really is, especially when
you compare it to choosing flight, which is mostly appealing
as this form of fast travel or experiencing this different sensation,
but it doesn't seem to have any of the darker edge,
right and you know. Barry found that people who choose
power of flight generally see it as a way to
add excitement or fulfillment to their lives. Whether that's from
you know, maybe rescuing people from burning buildings or just
(24:59):
zipping across the world to have dinner in Italy, or
you know, something like that, which is interesting. You know,
there's another commonality between invisibility fables that we should probably
talk about, all right, and what's that invisibility cloaks. So
ancient Greek myths described caps and cloaks with magical properties
that made the were invisible to other mortal men, and
from their invisibility, cloaks have popped up in everything from
(25:21):
Welsh and Germanic folklore to modern day pop culture. Of course,
and I'm guessing being a big fan, you're thinking of
Harry Potter definitely, So Harry Potter is never far from
my mind. But scientists have been hard at work on
cloaking devices for a while now, things that can mask
or completely hide an object or a person from sight.
And sometimes they're more successful than others. But all of
(25:42):
the most promising ones involves something called meta materials, and
it's just you know, some kind of super science cloth
or something more or less. So meta materials are basically
a kind of material that's engineered to have properties that
that don't occur in nature, and in this case, it's
a light bending property that manipulates by So the reason
objects are visible to our eyes at all is because
(26:04):
objects distort light waves based on their shapes. But when
the light from an object reaches our eyes, we see
the object by recognizing those distortions. Alright, so meta materials
they somehow counteract this or so. The idea is that
the meta material forms a kind of shell around the object,
or a cloak, so the light rays bends smoothly around
the meta material and recombined on the other side. And
(26:27):
one helpful example I came across is that it's kind
of like water flowing around a rock and a stream.
I viewer on the far side wouldn't see anything unusual,
but both the meta materials shield and object in its
center would be completely invisible to him. It would look
like the lights bouncing off a smooth surface, which is
pretty cool. But I don't know, I have the same thing.
I've read so many headlines over the last few years
(26:48):
that claim we're this much closer to Harry Potter like
invisibility cloak, And you know, there are definitely some similarities
to what you're describing, but it's hardly a one to want.
I mean, I mean, natural materials get their special properties
from the arrangement of atoms, and there's no way what's
going on with these meta materials is the same thing. Yeah,
that's true. And these cloaking devices are more like chunky
(27:09):
rings and pyramids that fit over a stationary object right now,
rather than any sort of sleek piece of fabric. But
the technology is advancing pretty quickly. Well, I'm glad to
know that we're on our way towards that. But why
don't we break for a little quiz? Alright, So today's
show us about invisibility. We decided to bring on to
(27:31):
Seattle based artists who produced the delightful art series that
only shows up when it rains. Welcome to the show,
Peregon Church and Zach Fisher. Thank you great to be here.
I am so excited to have you on. And and
for you listeners who aren't familiar with rain Works, you
should definitely check out the photo gallery at www dot
rain dot works because it's fantastic. So can you tell
(27:53):
us a little bit about how you came up with
this idea of making invisible artwork that only shows up
in the rain. I love thinking of ways to use
materials that already exists in ways that they shouldn't be used.
And I came across this stuff called super hydrophobic coatings. Basically,
when you put it on the surface, it keeps it
from getting wet, and I thought, wow, that's super cool.
(28:16):
You're watching all this water roll off these clothes and
shoes and whatever. What if you put it on something
that change color when it got wet, like concrete, and
so you since it's a spray on the thing, you
could spray it through a stencil on the concrete, and
as long as it was invisible and dry, you can
create art that was only visible when the surface is wet.
Would you tell our listeners a little bit about some
(28:36):
of the designs you do and how you make them interactive? Sure,
we like to do things that are positive, things that
don't make someone stay better. That's are really one of
the big motivations behind it. Because in Seattle and the
Pacific Northwestern general people tend to suffer from sad seasonal
effect of disorders. The skuys are gray and it's dreary
and wet all the time. So we figured we could
(28:58):
take that thing that causes the jurius the rain and
use it to make people smile. We did a lock
mass monster at a at a dock out in over
a lake here in Seattle Green Lake so that people
could stumble upon the monster while they were out on
rainy days. We do games. Sometimes, we've done like it
Don't Touch the Lava game. Um. We've done like nostalgic
(29:22):
references to like characters that we love as like when
we were kids. So like we've done like a Peter
Pan rainwork and like Calvin and Hobbs rain work. Basically
just whatever we think would like cheer someone up or
make them smile or make them think when they see
it it's funny. I mean even hearing the examples makes
you smile. That's pretty great. And you've now turned this
(29:43):
into a business. So what are the best applications of
your rain works? And you know that you've seen in
the wild. Now, oh man, we've seen so many some
all over the world. Some people have done like promposals
or actual wedding proposals with them. We've seen people use
public sountains to make like dolphins that appear. That's awesome. Yeah,
(30:04):
there was one just like a day or two ago
where they coated a canvas with it, then through water
balloons with like water based paint in them, through do
a gender reveal right back, that was what that was. Yeah, Yeah,
it's that kind of worked a little differently because our
spray doesn't repel paint, but it like reacted with it
in a certain way, so it does kind of make
(30:25):
the letters pop, but like not in the way you expect.
It's really interesting to see like a new application for it,
and that's really been the coolest thing is like just
since this started, it's really taken off just all around
the world, and we get like no one's popping up
in like Denmark and like Taiwan and like Armenia. Does
having worked on this project make you look forward to
(30:47):
rainy days? Like do you sit on benches waiting for
people to interact with the art? Oh? Absolutely. It has
completely changed our perspective on rainy days. And one of
our favorite things to hear when we tell people about
the project is them the words coming out of their mouths,
oh my gosh, I can't wait till it rains. Now,
like that means the world to us. We've become so
(31:10):
hyper sensitive to it that every time it starts to
rain or like the forecast predicts range like were like
on the edge of our sieves, like we're preparing, we're
making rain work. Our our whole work as well depends
on the weather. For sure, we'll tell us a little
bit about your connection with the Awesome Foundation. Sure. When
(31:30):
I had this idea, it was just an idea, like
on a note in my phone for a long time,
but it was one of one of my favorites, and
I started mentioning it to people and eventually mentioned it
to a friend in Seattle who was part of the
Seattle chapter of the Awesome Foundation. For anyone doesn't know,
the Awesome Foundation is an organization that every month it's
(31:54):
one dollars the person with a cool idea or an
awesome idea, as they put it, No, it's needs attached.
So I submitted this rain activated our idea, but we're
not called rain works to the Austin Foundation, and they
accepted it, and that was what really gave it the
first push. All right, Well, I thought we should play
a little game with these guys, and Mango, you came
(32:16):
up with one that's appropriate from what what game are
we playing with? A Peregrine and Zach. It's called I'm
Only Have You in It rains all right. We love
your Rainy Day project, and we figured we'd give you
a quiz where all the answers involved rain and you
can work together on this. So you guys ready, you're ready? Alright?
He got five questions for you, all right. Number One,
Gene Kelly had a one hundred and three degree fever
(32:38):
when he danced the big number in this rainy movie.
What classic film are we talking about? One? Number two,
Prince's manager questioned the decision to put When Doves Cry
in this movie slash album because the song didn't have
a baseline and he didn't think it would be a hit.
What Prince movie are we talking about? Purple Yes? All right?
(33:01):
Number three? All these pop culture references. I'm depending on
your's action. He's really pulling through, alright. Number three. During
the filming of this award winning movie, both Tom Cruise
and Dustin Hoffman thought the flick would be a clunker.
The whole time. They referred to it as two schmucks
in a car. What movie are we talking about? Wait?
(33:23):
I got this one, Raymond. Alright, with the big answer
here we go number four. Before this actor won the
role of Dwight Shrut on the Office seth Rogan had
auditioned for the role. Who are we talking about Wilson? Yes,
they both got that one, all right. The last question
see if you can get the perfect score number five.
(33:44):
This song, written by Paul Schaeffer and performed by the
Weather Girls, was intended to be a gay anthem, much
like Y M c A. You know the name of
the song, it's man. Yes, all right? How did they do? Mango?
Our howls when astounding five for five, which means we'll
be sending them our top prize, a handwritten note to
their mom or boss, singing their praises congratulations, m thanks
(34:09):
so much. Yeah, that's awesome. Listeners, please check out rain
dot Works when you get a second, and thank you
guys so much for all the work you do and
for putting smiles on so many faces having us. Okay, well,
(34:37):
so we talked about fictional invisibility cloaks as well as
the closest things. We have two real life ones. But
there's one more thing I want to talk about, and
it's the psychological sort. It's kind of a psychological invisibility
quote I don't even know how that would work. Is
like a helmet that would block your brain waves or
something like that. Yeah, that's a good guess, but no,
nothing like that. I'm actually talking about the great study
(34:58):
I came across about a I'm not called it invisibility
cloak illusion, and that's the name researchers at Yale University
came up with for our mistaken belief that we observe
others way more than others observe us. All Right, so
this is kind of like us pretending that maybe we're
under invisibility cloaks when we're out in public, if we're
grocery shopping or walking our dogs or something like that,
exactly pretty much any time we're in public, really, So
(35:21):
the team describes it this way, and they're abstract quote,
whether at a coffee shop, in a waiting room, or
riding the bus, people frequently observe the other people around them,
yet they fail to realize how much other people engage
in the same behavior, and that they therefore also are
being observed. Because it's logically impossible that people on average
(35:41):
are the subjects of observation more than they are objects
of it. The belief that one watches others more than
one is watched is an illusion that's pretty wild. I mean,
we feel like we're invisible, when the fact that we
observe others should tell us just the opposite of this.
And I really can't understand why we make this silly mistake,
because it's just that we're egomany acts, and you know,
we think we're the observant person and the only observant
(36:03):
person in a room. Yeah, that's definitely part of it.
But at least there's a good reason why we think
that way. And why is that? Well, the researchers at
Yale concluded that social norms compel our neighbors to pretend
to be busy with something else if it looks like
we might catch them watching us. All right, so we've
secretly scoped out the competition at a job interview, or
glanced around the waiting room and a doctor's office, and
(36:24):
just in case we need an alibi, we have a
magazine or something like that. It's funny that we all
assume we're the only ones who do this, though, right, so,
when it's actually so widespread and phenomena that it even
has its own name, researchers call it civil and attention.
I kind of like that, yeah, But my favorite part
of the study is this line from the conclusion, however
irresistible the sensation of being invisible, maybe it is not
(36:47):
to be trusted. That sounds exactly right, and it actually
makes it me think of this this other study I
read on the logic of the game Peekaboo. Apparently it's
this great display of the kind of nonsensical logic that
most kids share, namely the idea that you can make
yourself invisible by just covering your own eyes. So the
study was what like scientists rounded up a bunch of
toddlers and had this epic peekaboo session, Not exactly, but
(37:10):
but kind of. So the researchers at the University of
Cambridge had a group of three and four year olds
where I'm asked, and then they asked them whether they
could be seen by researchers or if they were invisible
to them. Then they asked the kids whether the researchers
would be able to see adults if those adults were
wearing eyemask like their's, and unsurprisingly, nearly all the kids
said they were hidden from view while their eyes were covered,
(37:33):
and most of them actually thought the imask would make
the adults invisible too, which is super cute. But did
the researchers have any ideas for why almost every child
subscribes to that weird logic. Well, actually, here's where things
get really interesting. And because when kids had their eyes covered,
they felt invisible, which fair enough, I mean, I think
we've all heard that before. But the researchers started to
(37:53):
press them on what invisibility meant, and surprisingly, the kids
conceded that their bodies weren't actually hidden it all all
in the sixth so they admitted their bodies could still
be seen even when their eyes were covered. So what
do they mean by invisible? So that's the weirdest part
and where this gets a little deep here. So the
implication was that the kids felt it was their true
self that was being hidden from view. So basically, they
(38:15):
were saying, I know, you can still see my arms
and my legs and all that when my eyes are closed,
but you can't see me, which is which is pretty existential,
you know, I know. It's it's like the children share
some natural distinction between you know, the physical body and
the metaphysical self. And I just find this stuff fascinating.
And you know, because most adults tend to think of
(38:36):
their consciousness and their body being joined together in some way,
and studies like this suggests that perception might be something
we only adopt or maybe decide on later in life. Yeah,
that's especially interesting when you think about how people always
say the eyes of the window to the soul, or
that eye contact Foster's understanding. I mean, in some ways,
covering your eyes really is like withdrawing yourself from the
(38:58):
world and making yourself invisible. Alright, well, Mango, you need
to keep those eyes open because there's only one thing
you can't hide from the PGG fact off exactly. All right,
here's something I hadn't thought about. Any lightbeam weapon you
(39:21):
see in the movies, from photon torpedoes to invisible rays,
they're all things you won't see coming so anytime as
sci fi heroes and a jet dodging those rays. None
of that's possible. You know that some of the things
you see in movies you just ruined all movies did so.
I want to know a figure who's basically become invisible
Jeremiah Dummer. Most people know. Yale University is named for
(39:42):
Elihu Yale, but Dumber probably did more for the early
university in terms of securing funds and building its reputation.
The problem is, Dumber College isn't a great name. Well,
Reindeer are good at spotting polar bears, Cameras aren't, so
when scientists decided to use infrared cameras to locate the bears,
they were stunned because polar bears are basically invisible to
infrared cameras too. While cameras can pick up the heat
(40:05):
off their nose and their breath, their blubber basically does
such a good job of trapping the heat within that
their fur is essentially the same temperature as all the
snow around it. So despite all the safety features and
cars with backup cameras and beeping sensors, people still back
up into lampos. So researchers at Kyo University in Japan
have come up with back seats that actually turned transparent
(40:27):
when you back up. Basically, it's a backup camera that
projects on the seats, but it does the trick of
seeming transparent and of course making the children sitting in
those seats disappear as another matter, definitely all right, here's
a fun one about not being seen. A building supervisor
in Spain skipped work for six years and kept collecting
his salary. You know the only reason he got caught.
(40:47):
People got suspicious when he won an award for twenty
years of loyal service. In two thousand six, Magician David
Copperfield and his two assistants were walking down the street
when mugger's approached and demanded all their money, and all
the assistants forked over plane tickets, cell phones, and over
five dollars in cash. Copperfield used sleight of hand to
show the gun wielding robbers that his pockets were empty.
(41:09):
He reperformed the trick at the police station and wow
the officers, showing them he actually had a passport and
lost with cash on him the whole time. I know
he's such a performer, but he did help catch the
bad guys and I kind of love it all right. Well,
in that case, I'm gonna have to give you today's
championship felt. So that's it for today's episode. Thanks so
much for listening, Thanks again for listening. Part Time Genius
(41:44):
is a production of how Stuff Works and wouldn't be
possible without several brilliant people who do the important things
we couldn't even begin to understand. Christa McNeil does the
editing thing. Noel Brown made the theme song and does
the MIXI MIXI sound thing. Jerry Rowland does the exact
producer thing. Gave Bluesiers our lead researcher, with support from
the Research Army, including Austin Thompson, Nolan Brown and Lucas
Adams and Eve Jeff Cook gets the show to your ears.
(42:07):
Good job, Eves. If you like what you heard, we
hope you'll subscribe, And if you really really like what
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Do we do? We forget Jason? Jason who
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