Speaker 1: Hey, Orgy. As an artist, do you have a favorite
Speaker 1: color that you use for scientific cartoons or some colors
Speaker 1: more sciency than others.
Speaker 2: Well, it depends on the science. I mean some science
Speaker 2: it's just more colorful than others.
Speaker 1: So then what's the color of physics?
Speaker 2: It kind of depends on the topic too. If it's
Speaker 2: about lasers, I might use red, or if it's about
Speaker 2: the sun, I might use a yellow. I've used cian
Speaker 2: for particle physics.
Speaker 1: What makes particle physics cian?
Speaker 2: I don't know. That just kind of would seem like
Speaker 2: fit to the topic at the time.
Speaker 1: It just gives you the blues.
Speaker 2: Yeah, Or if it's a red hot topic, I might
Speaker 2: go for a nice intense red. But for our books
Speaker 2: they usually go with purple.
Speaker 1: Yeah, what's purple about our curiosity?
Speaker 2: It's more about the process, you know. It's kind of
Speaker 2: mentally bruising, I mean mentally enlightening.
Speaker 1: I think it's position of both of those.
Speaker 2: It's both blue and red, which makes purple. There you go. Hi,
Speaker 2: I'm Hoorham Mack, cartoonas and the author of Oliver's Great
Speaker 2: Big Universe.
Speaker 1: Hi, I'm Daniel. I'm a particle physicist and a professor
Speaker 1: at U see irvine, and my daughter tells me I
Speaker 1: can't see mad.
Speaker 2: WHOA, wait, does that mean that you can't get mad
Speaker 2: or that you don't see the color red?
Speaker 1: Yes, As a parent of a stubborn toddler, I never
Speaker 1: once got mad. Absolutely kept my cool every single moment.
Speaker 3: No.
Speaker 1: She and I disagree a lot about what to call
Speaker 1: various colors, and she's convinced I'm partially colorblind.
Speaker 2: WHOA have you ever had it checked? Maybe it's true.
Speaker 2: What does that mean? You can't tell colors apart? Or
Speaker 2: you can't seek certain colors? But how do you know
Speaker 2: you can't see them?
Speaker 1: You can do these tests where you to see numbers
Speaker 1: out of dots. But she just likes showing me lots
Speaker 1: of different shades and asking me to come up with
Speaker 1: names of them. And I'm always like, I don't know
Speaker 1: wild Mountain raspberry, and she's like, that's not red, it's
Speaker 1: purple or something.
Speaker 2: Sounds like she just likes to disagree with you.
Speaker 1: Yeah, I think I raised her right.
Speaker 2: Yeah, you raised her to make you read all the time.
Speaker 2: But anyways, welcome to our podcast. Daniel and Jorge Explain
Speaker 2: the Universe, a production of iHeartRadio, in.
Speaker 1: Which we try to pencil in an explanation for how
Speaker 1: the universe works. We try to color inside the lines
Speaker 1: and help you understand how this incredible, glittering, beautiful, bizarre
Speaker 1: and crazy cosmos actually works, how all those quantum mechanical
Speaker 1: little particles come together to emerge into this incredible experience
Speaker 1: that we all enjoy.
Speaker 2: That's right. We try to paint a picture for you
Speaker 2: of our amazing and beautiful universe, using all of the
Speaker 2: hues of the rainbow to try to communicate to you
Speaker 2: all the feelings and impressions that the universe has in
Speaker 2: us as a human race.
Speaker 1: And in the end, science is trying to build a
Speaker 1: bridge between our visceral experience what you actually feel is
Speaker 1: a conscious entity, and our mental picture of what's out
Speaker 1: there in the universe, the mental model we're all putting
Speaker 1: together trying to explain how the universe itself, absent from
Speaker 1: our humanity, actually works. But in the end, we never
Speaker 1: probe that deep reality independent of our senses. We're only
Speaker 1: limited to understanding how it works as filtered by our
Speaker 1: eyes and ears and fingertips and everything else.
Speaker 2: Yeah, and as we look at the universe and filter
Speaker 2: it through our eye. Sometimes it makes us red with
Speaker 2: anger about the things we don't understand, or blue about
Speaker 2: the things we may never understand, and sometimes maybe even
Speaker 2: green and envy of maybe possible aliens out there that
Speaker 2: have figured it out. Did it miss a color? Orange?
Speaker 2: Mass orange? For a nice glass of orange?
Speaker 1: Aren't you glad you made that pun?
Speaker 2: Nice?
Speaker 1: All these things are part of our experience. The color
Speaker 1: purple in your mind is not actually part of the universe,
Speaker 1: is just part of your experience of the universe. Somehow,
Speaker 1: over the centuries and millennia, we have been able to
Speaker 1: piece together a picture of how the universe out there
Speaker 1: might actually work, perhaps independent of our senses, though of
Speaker 1: course we won't know until those aliens come and talk
Speaker 1: to us about the colors they see in the universe.
Speaker 2: Do you think they're a colored line too? Like Daniel,
Speaker 2: we think the answer to the universe is a light
Speaker 2: shade of lavender summer breeze. And then we would end
Speaker 2: up disagreeing about what that means.
Speaker 1: Yeah, I think whatever answer they have, my daughter will
Speaker 1: disagree with him. That's how I raised her.
Speaker 2: Let's not put her in the greeting committee.
Speaker 1: I think we agree on that Oh my gosh. Yes,
Speaker 1: let's not send Daniel's children to meet the aliens.
Speaker 2: Yeah, unless they start an intergalactic war.
Speaker 1: Maybe the colors are sacred to them, and if Hazel
Speaker 1: disagrees about what's purple and what's red, she's going to
Speaker 1: really piss them off.
Speaker 2: Yeah, or they might disagree about the color hazel itself.
Speaker 1: That's right. Yeah, exactly why are.
Speaker 2: You called hazel if you're not the color of a
Speaker 2: hazel nut. That's it. Forget this human race. It doesn't
Speaker 2: make any sense.
Speaker 1: It doesn't make any sense. You know, we named it
Speaker 1: her hazel before we knew her. But she does turn
Speaker 1: out to light the color hazel and hazel nuts, so
Speaker 1: there's a win.
Speaker 2: Yeah, but how do you know she's actually seen the
Speaker 2: color Hazel's hazel blind?
Speaker 1: M hazel blind.
Speaker 2: Wow, it's all hazey to her, it is.
Speaker 1: But we are fascinated by this concept of color, not
Speaker 1: just because it's such a visceral part of our experience,
Speaker 1: but because it's deeply connected to the physics of what's
Speaker 1: happening out there in the universe. It tells us something
Speaker 1: about how photons are wiggling, or how neutrinos are flying
Speaker 1: through the universe if you're willing to apply red and
Speaker 1: blue shifts to them as well. So this concept of color,
Speaker 1: what we see, what's out there in the universe, it's
Speaker 1: very confusing but also very illuminating about how the universe
Speaker 1: actually works.
Speaker 2: Yeah, there's a lot of physics in light and in
Speaker 2: all the colors. But then, as you said, it gets
Speaker 2: filtered through our eyes and our brains, and sometimes what
Speaker 2: we see is not quite what's out there, and maybe
Speaker 2: there might be things out there that are maybe impossible
Speaker 2: for us to experience.
Speaker 1: Well, that's right. We know that there are frequencies of
Speaker 1: light the humans can never experience, but are there also
Speaker 1: colors that are impossible to see?
Speaker 2: So to the end podcast, we'll be tackling the question
Speaker 2: what is an impossible color?
Speaker 1: It sounds like a job for Tom Cruise.
Speaker 2: Dunt dunt dan da dunt dun.
Speaker 1: This color will self destruct after you view it.
Speaker 2: We need a movie in which Tom Cruise is a physicist. Yeah,
Speaker 2: I mean he'd have to wear a lot of like
Speaker 2: wigs and prosthetics. Of course, he can't look like Tom Cruise.
Speaker 1: Yeah, he's too sexy to be a physicist. Is that
Speaker 1: what you're saying? I didn't say that he violates some
Speaker 1: physical law.
Speaker 2: He's too orange.
Speaker 1: He's definitely very physical, even if he's not a physicist,
Speaker 1: Right he doesn't.
Speaker 2: Yeah, that's right. Yeah. I wonder if he would do
Speaker 2: his own stunts in a physics movie, Like would you
Speaker 2: actually sit on the couch all day? I mean, that's
Speaker 2: it's probably more dangerous and jumping off a cliff.
Speaker 1: Then you put all those professional nap stunters out of work.
Speaker 1: You can just take naps on film as a wait.
Speaker 2: Wait, wait, that's a career. I can be a stunt
Speaker 2: napper exactly.
Speaker 1: Oh man, there's a career for everything.
Speaker 2: They're doing it all this time for free. Daniel.
Speaker 1: You know that the sign of an advanced civilization is specialization, right,
Speaker 1: And I think once we've achieved stunt napping, we've reached
Speaker 1: the pinnacle of civilizations. The aliens will be impressed.
Speaker 2: Oh, they might even hire us to nap for them.
Speaker 1: Well there's a.
Speaker 2: Twist ending, but yeah, this is an interesting question, the
Speaker 2: idea that there might be colors out there that are
Speaker 2: impossible to create, to experience, to see, to generate what
Speaker 2: side of the color spectrum.
Speaker 1: Are we Yeah, it's a complicated question. Because color is
Speaker 1: intimately connected with frequency, and we think about it as
Speaker 1: controlled by light, but really it's something inside our minds,
Speaker 1: it's something generated by our brain. It's an experience, and
Speaker 1: the colors you experience in the end come from the
Speaker 1: signals that travel up the optic nerve, which are not physical.
Speaker 1: They're just interpreted by your brain. And so it's interesting
Speaker 1: to think about whether there are colors that cannot be
Speaker 1: described by those signals.
Speaker 2: Oh boy, is this going to get into philosophy, Daniel, Like,
Speaker 2: what colors can a bat see?
Speaker 1: That's actually a great idea for paper. I'm gonna write
Speaker 1: that when we're done with this episode.
Speaker 2: Yeah, what color is your bad wing?
Speaker 1: Everything in the end is philosophy if you care about
Speaker 1: what it means. Right, So if you're going to answer
Speaker 1: the question what does that mean anyway? Then yeah, you're
Speaker 1: getting into philosophy.
Speaker 2: That sounds like a philosophical statement in itself, Daniel.
Speaker 1: The philosophy of philosophy.
Speaker 2: Yeah, you can get a phphphd in recursive philosophy in
Speaker 2: computer science philosophical puzzles well, as usually. We were wondering
Speaker 2: how many people had thought about this question of what
Speaker 2: is an impossible color, and so as usual, Daniel went
Speaker 2: out there to the Internet to ask people this question.
Speaker 1: Thanks very much to everybody who answers these questions for
Speaker 1: the podcast. If you would like to hear your voice
Speaker 1: on future episodes, please write to me two questions at
Speaker 1: danielan Jorge dot com.
Speaker 2: So think about it for a second. What do you
Speaker 2: think is an impossible color? Here's what people had to say.
Speaker 4: So, color is just a construct of our brain decoding
Speaker 4: the frequency of electiation. If you think about it and
Speaker 4: imagine our rods and cones were tuned a little wider
Speaker 4: and we could actually see an infrared and ultraviolet, and
Speaker 4: colors we can't see would be associated with those frequencies.
Speaker 4: So I guess every color associated with low frequency radio
Speaker 4: all the way to gamma rays would be impossible colors.
Speaker 3: If color is just how we perceive different wavelengths of light,
Speaker 3: and light can be in a huge range of wavelengths.
Speaker 3: It has something to do with the limits of the
Speaker 3: wavelength approaching either zero or infinity, where suddenly color doesn't
Speaker 3: make any sense anymore.
Speaker 5: An impossible color all very interesting. I'm going to say
Speaker 5: some sort of combination of spectral outputs that are that
Speaker 5: is a different spectral resolution than what our the receptors
Speaker 5: of our eyes are able to something to do with
Speaker 5: color metamerism.
Speaker 2: The interesting answers. I feel like nobody pitched the idea
Speaker 2: that maybe it's a color that's made out of plant based.
Speaker 1: Proteins vegan colors.
Speaker 2: Wow, yes, No, no animals or creatures were harmed in
Speaker 2: the making of this color.
Speaker 1: I can't even imagine a way you might harm an
Speaker 1: animal to make a color you're talking about, like, oh,
Speaker 1: let's see red, We're going to spill something's blood. Like
Speaker 1: it seems pretty unnecessary.
Speaker 2: I think, Daniel, you just don't have this strong enough imagination.
Speaker 2: But there are colors that are based on or traditionally
Speaker 2: there are dyes that are based on like insects, like
Speaker 2: insect juice.
Speaker 1: Oh yeah, okay, interesting, But.
Speaker 2: I don't know how vegans draw that line.
Speaker 1: You know, we're gonna have to have some of them
Speaker 1: on the podcast to answer the question.
Speaker 2: Yeah, sounds like good question for Katie. All right, well,
Speaker 2: let's dig into this question of what an impossible color is.
Speaker 2: Whether it means we can't see it, we can't make it,
Speaker 2: it can't exist in the universe. Let's figure it out.
Speaker 2: So you know, what are the basics of light and color?
Speaker 1: Yeah, so let's start outside the human brain before we
Speaker 1: get into like signal processing and all that stuff, and
Speaker 1: just begin with light. Right, Light we know is made
Speaker 1: of electromagnetic fields. There are ripples in electromagnetic fields, So
Speaker 1: we have electrical fields that can be made by like
Speaker 1: electrons and magnetic fields that have made my magnets. And
Speaker 1: light is a coupling of the electric fields and the
Speaker 1: magnetic fields together. Electric fields can induce magnetic fields, magnetic
Speaker 1: fields can induce electric fields. Light is like this perfect
Speaker 1: little packet where it's slashing back and forth between electric
Speaker 1: fields and magnetic fields in amazing harmony, and they can
Speaker 1: propagate through the universe, this little oscillation of the fields.
Speaker 1: And these oscillations have frequencies that have a wavelength, they
Speaker 1: have a frequency that relates to their energy. So if
Speaker 1: you have a beam of light, for example, coming out
Speaker 1: of a flashlight, it's actually made out of little photons,
Speaker 1: and each photon has a specific energy which has a
Speaker 1: specific wavelength and a specific frequency. So that's what light is, right,
Speaker 1: these packets of photons.
Speaker 2: So I have this laser and I'm shooting it, and
Speaker 2: there are photons coming out of it, and each photon
Speaker 2: is like a wiggle in the electromagnetic field. Is that
Speaker 2: what it is?
Speaker 1: Yeah, each photon is a wiggle in the electromagnetic field.
Speaker 2: But it's not a wiggle that's like propagating, like if
Speaker 2: I throw a pebble in a pond. It's not spreading
Speaker 2: out there like that, right, Like in a laser. These
Speaker 2: things are going in a straight line.
Speaker 1: These things are going in a straight line. And we
Speaker 1: just did a really fun but very confusing episode about
Speaker 1: how long is the photon? And if you didn't listen
Speaker 1: to that one, I.
Speaker 2: Was going to listen to it, but it's a little long.
Speaker 2: I'm not a light topic.
Speaker 1: And that tells you that real photons out there in
Speaker 1: the universe are a little packets. They have a length
Speaker 1: that's determined by the spread of the frequency. So in
Speaker 1: a sort of idealized sense, you can imagine every photon
Speaker 1: has exactly one frequency. It's like a pure little packet
Speaker 1: of one energy, one wavelength, one frequency. But that's actually
Speaker 1: mathematically very confusing because if it was like that, it
Speaker 1: would be everywhere in the universe. And so to build
Speaker 1: up a little packet that actually moves through the universe
Speaker 1: a little blob that stays together and flies through space.
Speaker 1: You have to have a little bundle of frequencies, so
Speaker 1: you know, blue photon is like a little spread of
Speaker 1: various blue frequencies, and a red photon is a little
Speaker 1: packet of a handful of differently red frequencies.
Speaker 2: And they're all going at the same speed, which is
Speaker 2: the speed of light.
Speaker 1: Yes, exactly, they all got the same speed even though
Speaker 1: they have a different wavelength and a different frequency, and
Speaker 1: the speed of light is the same across the spectrum.
Speaker 1: That's at least in our current theory. There are theories
Speaker 1: of physics like rainbow gravity, where different frequencies travel at
Speaker 1: different speeds and you get like effects around the edges
Speaker 1: of black holes, but are in their current theory physics,
Speaker 1: And according to all of our measurements, every photon travels
Speaker 1: at the same.
Speaker 2: Speed, and the spectrum of frequencies that light can have,
Speaker 2: it's basically one dimensional, right, Like there's only one knob
Speaker 2: for the frequency of light.
Speaker 1: Yeah, if you're going to think about a photon.
Speaker 2: From zero to infinity, hmm, But it's just a line,
Speaker 2: and if you were to draw a plot of it.
Speaker 1: Yes, exactly, it's one dimensional. It's a great way to
Speaker 1: think about it. And it is infinitely dense, right, there's
Speaker 1: an infinite number of frequencies there. We think of these
Speaker 1: things as like, oh, they're quantum mechanical, so it must
Speaker 1: be discrete, must be broken up into chunks, right, But
Speaker 1: the reality is that free objects, even free electrons, are
Speaker 1: not quantized in their energy levels. They're quantized in the
Speaker 1: number of photons. Like you can't have one point seven
Speaker 1: photons or two point two seven photons. You can have
Speaker 1: one or two or nineteen. But each photon can have
Speaker 1: any energy. There's no limitation, there's no quantitization, there's no
Speaker 1: descritization of the energy spectrum. But yes, it is one
Speaker 1: dimension all.
Speaker 2: That you know of though, right, Like, is it possible
Speaker 2: that maybe frequency is quantized as well.
Speaker 1: Yeah, in our current theory that's the case. There are
Speaker 1: theories of quantum gravity in which like space is pixelated,
Speaker 1: which would make like a minimum wavelength, and in that
Speaker 1: case every distance is quantized. In our current theories, there's
Speaker 1: no minimum frequency, but that doesn't actually really make sense
Speaker 1: below like the plank length, where every photon would like
Speaker 1: collapse into a black hole anyway, So it only really
Speaker 1: applies up to a very very high energy, but much
Speaker 1: higher than we could probe today.
Speaker 2: All right, So that's the physics of it. Now let's
Speaker 2: get into the biology of it. So when these photons
Speaker 2: hit our eyes, they create and experience in our brains.
Speaker 1: Yeah, I think there's one step before that, which is reflection. Like,
Speaker 1: let's imagine we're looking at a banana, right, why do
Speaker 1: we see the banana as yellow? We see the banana
Speaker 1: as yellow because white light hits the banana from the sun,
Speaker 1: and then some of it is absorbed and some of
Speaker 1: it is reflected. You start with almost every frequency of
Speaker 1: light you can see the banana, But then the banana
Speaker 1: has chemicals in it and atoms, and those atoms prefer
Speaker 1: to absorb some colors and not absorb other colors. And
Speaker 1: so when you see yellow as banana, that means that
Speaker 1: the wavelength of light that is being reflected is a
Speaker 1: specific band in this case, like between five hundred and
Speaker 1: seventy and five hundred and eighty nanometers. So you see
Speaker 1: something as red, it's not because it's like absorbing the
Speaker 1: red light, right, It's because it's reflecting the red light
Speaker 1: and absorbing everything else. But then yeah, it hits your eyeball,
Speaker 1: and those photons with a certain frequency are now going
Speaker 1: to be interacted with by your eye, which is like
Speaker 1: basically little observational device.
Speaker 2: But wait, the banana, So the banana absorbs all frequencies
Speaker 2: except maybe the kinds that are my brain will interpret
Speaker 2: as yellow.
Speaker 1: Yeah, not all frequencies, but all visible ones. Right, banana
Speaker 1: can't necessarily absorb all X rays and gamma rays or infrared,
Speaker 1: but in the visible spectrum and again, and not even
Speaker 1: all of that, right, Like you see it yellow because
Speaker 1: it's dominant in the yellow. It's never like intense and
Speaker 1: yellow and zero in every other frequency. You know, it just.
Speaker 2: Peaks unless it's like a perfect banana. Like, is it
Speaker 2: possible to create a perfect banana that only reflects like
Speaker 2: one frequency of yellow.
Speaker 1: If you make a shade which only reflects one frequency
Speaker 1: of yellow, I think Hazel would call that perfect banana.
Speaker 1: That is a nice name for a yellow.
Speaker 2: Exact banana, yes.
Speaker 1: Exact scientific banana.
Speaker 2: Okay, So there's a reflection and also I mean there's
Speaker 2: filtering too. But while we're talking about it, like it right,
Speaker 2: like if I have rose colored glasses, the world looks
Speaker 2: rose to me. Because it's filtering out all frequencies except
Speaker 2: the ones that I see is rose.
Speaker 1: Yeah, exactly, it's filtering. There's a reflection. All this affects
Speaker 1: the frequencies that actually hit your eyeball. But I hear
Speaker 1: a lot of confusion out there and the questions I
Speaker 1: get from listeners about what makes something a color, whether
Speaker 1: it's absorbing it or reflecting it, And so it's important
Speaker 1: to remember that the color is something that's in your
Speaker 1: eye depends on the light that hits your eyeball. You
Speaker 1: can only see something if it hits your eyeball. For example,
Speaker 1: if a photon was flying in front of you your face,
Speaker 1: you couldn't see it right. If it just flies past you,
Speaker 1: you don't see like a little glowing blob going through
Speaker 1: the universe. You imagine your visual perception is giving you
Speaker 1: an accurate description of everything that's out there in the universe,
Speaker 1: but you only see things that hit your eyeball. Photon
Speaker 1: that passes in front of you doesn't send any signals
Speaker 1: to you, so you don't see it right.
Speaker 2: Like if someone to my right shoots a laser to
Speaker 2: my left, I won't see it. It has to be
Speaker 2: they have to be shooting into my eye for me
Speaker 2: to see the.
Speaker 1: Laser, yeah, or it has to hit dust particles along
Speaker 1: the way or air and ionize that and make a
Speaker 1: glow or a reflection. Right, But a perfect laser in
Speaker 1: a vacuum you will not see until it slices your
Speaker 1: head open.
Speaker 2: The photons, ever, split into other photons.
Speaker 1: Photons can convert into electron positron pairs, which can then
Speaker 1: interact with other stuff, like including other photons, and do
Speaker 1: crazy stuff that differently could happen, and those could create
Speaker 1: other photons, So that can happen, but it's quantum mechanically
Speaker 1: pretty rare. If you pass a photon through a special
Speaker 1: kind of non linear crystal, it can split into two
Speaker 1: other photons. They use that for important experiments to like
Speaker 1: detect single photons. But mostly photons just fly through the universe.
Speaker 1: That's why we can see them after billions of years
Speaker 1: and across billions of light years. They're pretty reliable indicators
Speaker 1: of what emitted them.
Speaker 2: All right, So photons can't have all these frequencies. Sometimes
Speaker 2: they get filtered, or when they bounce off the things
Speaker 2: they get some of them make it out of the
Speaker 2: bounds and they sometimes hit our eyes, and then that's
Speaker 2: our experience of seeing things.
Speaker 1: Yeah, exactly, and also our eyeballs do some filtering, right
Speaker 1: to be experienced, the photon has to make it into
Speaker 1: the pupil and then through the lens and then all
Speaker 1: the way to the back of the retina where it
Speaker 1: can actually be interacted with. That's where there are these
Speaker 1: proteins which either turn on or turn off based on
Speaker 1: the frequency of light. So you have these like array
Speaker 1: of sensors in the back of your eyeballs which can
Speaker 1: detect photons.
Speaker 2: Did you look into how that works? Like there's a
Speaker 2: molecule on the surface of the receptor there and then
Speaker 2: it just gets activated and it wiggles, and then how
Speaker 2: does that? Does it release a chemical or does it
Speaker 2: create an action potential? How does it work?
Speaker 1: Yeah, it's actually really amazing. It's like a little machine
Speaker 1: and it actually changes the protein's configuration when it absorbs
Speaker 1: the photon. It flips like almost a physical switch on
Speaker 1: this chemical to change its configuration and that adds energy
Speaker 1: to it and then that's picked up by the optic nerve.
Speaker 1: It's really kind of amazing chemistry. And you have these things.
Speaker 1: They're scattered all over the back of your eye. Of course,
Speaker 1: people know there's two different kinds. There's rods, which basically
Speaker 1: give you black and white vision. They're sensitive across the spectrum.
Speaker 2: Wall what does that mean, Like any photon of any
Speaker 2: frequency will activate them or not.
Speaker 1: It's not exactly flat across the spectrum. But essentially, yes,
Speaker 1: they're not very frequency specific, they're not choosy. They're very
Speaker 1: very sensitive. Yeah, they're not choosy, but they're very good
Speaker 1: at picking out photons. They're much better than the cones.
Speaker 1: So they're good for like at night, is there a
Speaker 1: predator there or not? You don't really care if to
Speaker 1: red or green. You just want to know if it's
Speaker 1: something there.
Speaker 2: Basically gives the sense of like brightness or darkness.
Speaker 1: Yes, exactly, it's like black versus white. But then you
Speaker 1: have these other sensors, these cones. There's three different kinds
Speaker 1: of them. You have like six or seven million in
Speaker 1: the back of each eyeball, and most of them are
Speaker 1: actually concentrated in a tiny little spot in the retina
Speaker 1: near the center of your vision. So you have like
Speaker 1: color vision near the center of your eyeball, but mostly
Speaker 1: black and white in the rest, which is fascinating and
Speaker 1: each of these cones responds to a different frequency of light,
Speaker 1: so it has like a protein on it, and a
Speaker 1: different protein for each kind. You have three different kinds,
Speaker 1: and those proteins are tuned to flip or to not
Speaker 1: flip for different frequencies of light. So one of them
Speaker 1: mostly flips on for blue light, another one mostly flips
Speaker 1: on for green, another one flips on for like yellowish red.
Speaker 2: Light, and it so did they sort of ignore the
Speaker 2: other frequencies.
Speaker 1: They don't exactly ignore them, right, They're not in very
Speaker 1: narrow bands. So one of them does peak in the blue,
Speaker 1: and one peaks in the green, and one peaks in
Speaker 1: the red. If you imagine, like, what's the probability for
Speaker 1: this protein to flip based on the frequency of light, Well,
Speaker 1: the blue one will almost always flip for a blue one,
Speaker 1: but it'll sometimes flip for a green one, though not
Speaker 1: as reliably. And the red one will always flip for
Speaker 1: a red one, and sometimes for a green one, and
Speaker 1: occasionally even for a blue one. So they're a little
Speaker 1: bit overlapping. They're not like perfect bands.
Speaker 2: Right, They're fuzzy. They can each will react to a
Speaker 2: certain range of frequencies where those freagancies are centered. It
Speaker 2: kind of depends on the type of cone.
Speaker 1: Yeah, exactly. And so you have three of these, each
Speaker 1: of which are centered at different places in the spectrum.
Speaker 1: And then what your brain does is interpret the signals
Speaker 1: from these cones to figure out, oh, how blue was it. So,
Speaker 1: for example, if you get a signal only from blue
Speaker 1: cones and nothing from the red and the green one,
Speaker 1: then you're like, Okay, that must have been pretty blue
Speaker 1: in order to signal the blue ones and not signal
Speaker 1: the other ones. But if you get something that signals
Speaker 1: the blue one and the green one and not the
Speaker 1: red one, then you're like, okay, it was blue green.
Speaker 1: And so you can sort of triangulate where it is
Speaker 1: on the spectrum by the ratios of how these things react.
Speaker 2: Interesting. All right, Well let's get to this idea that
Speaker 2: maybe there are colors that are impossible for us to
Speaker 2: see even with our rods and cones. So let's dig
Speaker 2: into that. But first let's take a quick break. All right,
Speaker 2: we're talking about color today, hopefully not getting too off color.
Speaker 1: Depends on if you think philosophy is off color or not.
Speaker 1: What is the color of philosophy?
Speaker 2: WHOA, Well, that's getting a little purple there.
Speaker 1: I didn't mean to ask a lavender question.
Speaker 2: Well you don't have to yellow it, Daniel. All right, Well,
Speaker 2: we're talking about how we experience light, and so we
Speaker 2: know that light are photons. They come in different frequencies.
Speaker 2: There are frequencies from here to infinity. But our eyes
Speaker 2: have these sensors that can detect photons around certain frequencies,
Speaker 2: and those are the ones that generally we would associate
Speaker 2: as red, green, and blue rightb RGB.
Speaker 1: And it's fascinating that here we've transformed, as you said,
Speaker 1: an infinite one dimensional spectrum. Photons could be anywhere along
Speaker 1: the spectrum. So now sort of this three D spectrum
Speaker 1: RGB right, and the color that we perceive depends in
Speaker 1: principle on the photon, but really it depends on the
Speaker 1: signals from these neurons, which is in this three D
Speaker 1: space of red, green, or blue. You get these signals
Speaker 1: from these neurons, and once you experience is in your mind,
Speaker 1: it is just an interpretation of this point in this
Speaker 1: three dimensional RGB space.
Speaker 2: I guess maybe a question you could ask is like,
Speaker 2: why are we doing it this way? Why are we
Speaker 2: seeing the world this way? Why don't we just why
Speaker 2: didn't evolution come up with this answer that can just
Speaker 2: tell you what the frequency of light is.
Speaker 1: That's fascinating question. And there are some close based on
Speaker 1: the variety of the way the color perception works in
Speaker 1: the animal kingdom, Like we know that we have these
Speaker 1: three sensors, but there's nothing special about three. Like people
Speaker 1: think of RGB as the fundamental basis of color, but
Speaker 1: it's just so the way the human eye works. There
Speaker 1: are critters out there with like eleven different sensors. The
Speaker 1: mantis shrimp, I think has like fourteen, and there are
Speaker 1: and there are species out there that can see a
Speaker 1: broader range or a narrower range of colors, just depends
Speaker 1: on what's more efficient. The fascinating thing is that the
Speaker 1: more sensors you have, the better you are typically of
Speaker 1: being able to tell the difference between shades. So if
Speaker 1: you like really need to know the difference between dark
Speaker 1: green and light green, you might evolve more sensors or
Speaker 1: more sort of like processing power to be able to
Speaker 1: distinguish these signals.
Speaker 2: Yeah, I guess the more sensors you have, like kind
Speaker 2: of like posts you put in the frequency spectrum, the
Speaker 2: more you can tell things apart.
Speaker 1: Sometimes, like the mantis shrimp is famous for having like
Speaker 1: fourteen different sensors. You might think, wow, they must see
Speaker 1: the world in really vivid color, but they have very
Speaker 1: very few neurons to back it up behind that, so
Speaker 1: it's like they have really really good hardware but terrible software.
Speaker 1: So they might actually not experience more colors than we do,
Speaker 1: like the actual experience of a Manti strip. Who can
Speaker 1: never know right until we write that paper. But I
Speaker 1: think it takes both complex hardware and complex software to
Speaker 1: experience a broad variety of colors.
Speaker 2: I'm sure those fourteen centers are doing something right, like
Speaker 2: it's letting it discriminate a certain specific colors or certain
Speaker 2: specific patterns. But maybe after that, it's just not like
Speaker 2: the man district is not appreciating the color.
Speaker 1: It depends a lot on the processing, right. You get
Speaker 1: these signals if you have very crude responses to them,
Speaker 1: very crude like neural networks behind them to help you
Speaker 1: know how to respond to them, very wide bins in
Speaker 1: your response, for example, you could be wasting a lot
Speaker 1: of that information.
Speaker 2: You know.
Speaker 1: Imagine you have like a super excellent microphone and then a
Speaker 1: terrible cable to store it in very low fidelity file
Speaker 1: format could be very lossy. This is all very very speculative,
Speaker 1: of course, and there's experiments going on to try to
Speaker 1: understand what mentis shrimp experience. But there are some humans
Speaker 1: that have more than three cones. They're called tetra worlds. Yeah,
Speaker 1: like mutants, Yes, mutants exactly, But there are people have
Speaker 1: four different kinds of cones. When I first heard of that,
Speaker 1: I thought, WHOA, they must have a fourth color.
Speaker 2: How does that happen? Like they have a mutation that
Speaker 2: produces a whole different fourth kind of cone.
Speaker 1: Yeah, they're very rare. Then you can spot them, not
Speaker 1: because they see a different color we think. It's not
Speaker 1: like there's a fourth color that adds to RGB that
Speaker 1: they can experience that we can't. It's just that they
Speaker 1: tend to be better discriminating between colors, so like they
Speaker 1: might pass a color blindness test that the rest of
Speaker 1: us would fail. If you put like a really really
Speaker 1: subtle difference between the greens and the blues, for example,
Speaker 1: they might pick something out that other people can't.
Speaker 2: You put like a Stamp athlete next to a Harvard athlete,
Speaker 2: and you'd ask them like which one is which You'd
Speaker 2: be like, wait, what, they're the same? They just look red.
Speaker 2: But you know, maybe a more discerning person might say,
Speaker 2: oh no, that's a crimson, and then the other one's
Speaker 2: like a wine red.
Speaker 1: Junior college red. Yeah exactly. Yeah, yeah, way to come
Speaker 1: up with an example that's really relatable, I'm suing a
Speaker 1: lot of people have really struggled with their things.
Speaker 2: I mean, if you put a banana slug next one
Speaker 2: and eater, is it the same yellow or not?
Speaker 1: You know, that's actually a really fun question because all
Speaker 1: the University of California campuses are blue and gold, but
Speaker 1: they all have different shades of gold.
Speaker 2: Now, which one is more relatable? To exclude people who
Speaker 2: don't live in California, or to exclude people who've never
Speaker 2: heard of Stanford and Harvard?
Speaker 1: I don't know. Let's hear from the listeners.
Speaker 2: They're gonna be like, you excluded everyone.
Speaker 1: Anyway. It's fascinating because the biological transformation of these photons
Speaker 1: into optic signals puts us sort of like a distance
Speaker 1: from the actual photon. Like what you're experiencing in your
Speaker 1: mind is reaction to the optic nerve signals, not the
Speaker 1: photon directly.
Speaker 2: Well, it lands in your cone and then the cone
Speaker 2: generates the signal that then gets transmitted to your brain.
Speaker 1: Yeah, exactly what you mean. But you could simulate that
Speaker 1: signal without the photon, right, You create that same signal
Speaker 1: the optic nerve somehow without the photon, sort of the
Speaker 1: matrix style. You can experience that color without a photon,
Speaker 1: of that energy actually arriving on your optic nerve, and
Speaker 1: it tells you that. Like we say, photons have color,
Speaker 1: we call them red photons or blue photons, but that's
Speaker 1: not really accurate. The photons themselves don't have a color.
Speaker 1: The color is in your mind. The photons have an energy,
Speaker 1: to have a frequency, to have a wavelength. The color
Speaker 1: is just like your experience of the photon.
Speaker 2: Well, I mean, it's our brains trying to figure out
Speaker 2: what that frequency is. It just that we came up
Speaker 2: with a name for things like, oh, that's thirty point seven.
Speaker 2: Her have a prequancy light. We will call that yellow.
Speaker 2: Why not because we don't have decimal numbers back in
Speaker 2: the day.
Speaker 1: It's our brain trying to give us what it thinks
Speaker 1: is a useful experience or what evolution has proven to
Speaker 1: be a useful experience, the way that, like touching something
Speaker 1: hot gives you a painful experience, turns out to be useful.
Speaker 1: Having these different experiences in your mind for these different
Speaker 1: bands of frequencies turns out to be useful. But what's
Speaker 1: fascinating is a sort of philosophical question of like, where
Speaker 1: do these experiences themselves come from? And are they the same?
Speaker 1: You know, you put two people in black and white
Speaker 1: rooms and raise them without color and describe colors to them.
Speaker 1: Could they come out of that room and identify red
Speaker 1: versus blue versus green? Or is it purely captured in
Speaker 1: the innate experience and can never be described in any
Speaker 1: other terms. There are fascinating philosophical questions.
Speaker 2: I think it has been proven our brains have evolved to
Speaker 2: react to certain colors in certain ways, right, Like green
Speaker 2: usually has a calming effect, Red has a certain sort
Speaker 2: of anxiety raising effect. Right is that kind of what
Speaker 2: you mean, like our brains are cute to react to
Speaker 2: startain colors or what.
Speaker 1: I'm not familiar with those studies, though imagine it's probably
Speaker 1: is true that there are emotional responses to various colors.
Speaker 1: But I mean, like the actual experience of the color,
Speaker 1: Like the red that you feel in your mind is
Speaker 1: just an experience in your mind the way pain is right,
Speaker 1: Pain is like a reaction to heat, to damage, to temperature.
Speaker 1: Red is a reaction to certain frequencies of light hitting you.
Speaker 1: But the light itself is not red, the way that,
Speaker 1: like the heat from the burner, is not actually literally painful.
Speaker 1: The pain is part of your experience of it.
Speaker 2: Yeah, yeah, I guess, But I feel like maybe we're
Speaker 2: sort of maybe confusing things by trying to get to philosophical.
Speaker 2: It's basically just your brain trying to detect what's happening
Speaker 2: in the world, right, Yeah.
Speaker 1: It's your brain's interpretation of these signals. And you're right,
Speaker 1: Getting philosophical does always confuse things because you end up
Speaker 1: with questions you can't answer and you don't know if
Speaker 1: they actually tat you anything.
Speaker 2: So then let's get back to this topic of it.
Speaker 2: Maybe that there's a color that it's impossible for us
Speaker 2: to see or to make we're both.
Speaker 1: Yeah. A few decades ago a theory developed about how
Speaker 1: we experience color. It's actually slightly more complicated and actually
Speaker 1: slightly simpler than what we just described. Instead of imagining
Speaker 1: that you get like three signals red, green, and blue
Speaker 1: actually the way.
Speaker 2: That but I guess maybe just from a very basic
Speaker 2: level of course, our colors we can see, like we
Speaker 2: can't see light up up on the infrared, and we
Speaker 2: can't see light down or up in the ultraviolet. Right, Like,
Speaker 2: there's a whole range of light frequencies, infinite range of
Speaker 2: light frequencies that were our eyes just don't detect, Like
Speaker 2: they just go through our eyes or they hit our
Speaker 2: eyes and don't activate it.
Speaker 1: Right, Yeah, absolutely, there are lots of frequencies of light
Speaker 1: that don't generate in the signal. I don't know if
Speaker 1: those frequencies of light have a color though, right, color
Speaker 1: is just our experience, and so you just don't assign
Speaker 1: a color to those frequencies. So there are frequencies we
Speaker 1: cannot see. I don't know if those frequencies have color.
Speaker 2: What would you call a color?
Speaker 4: Was it?
Speaker 2: Like if we have like a visual spectrum, right, Like,
Speaker 2: there's a range of frequencies that our eyes can detect,
Speaker 2: and so let's call color the light that is within
Speaker 2: that range, the frequency of the light within that range.
Speaker 1: Yeah, I would say color is our response to frequencies
Speaker 1: of light within that range.
Speaker 2: Okay, I mean that sounds like an arbitrary definition. I
Speaker 2: could also just posit colors the frequency of the light
Speaker 2: that we can see, so.
Speaker 1: That all works really well. If you think about individual
Speaker 1: frequencies of light, it all makes sense. But you know,
Speaker 1: we never see individual frequencies. You always see a mixture.
Speaker 1: You see a little bit of this frequency, a little
Speaker 1: bit of that frequency. And once we start thinking about
Speaker 1: mixtures of frequencies, things get more complicated. And actually a
Speaker 1: different theory of how we experience color emerged a few
Speaker 1: decades ago. It's called opposing neuron theory. It says, instead
Speaker 1: of having like a three dimensional space RGB red, green,
Speaker 1: and blue one for each of these different kinds of cones,
Speaker 1: actually we only really have two because we have opposing neurons.
Speaker 1: That we have neus the fire more when light is
Speaker 1: red and less when it's green. And we have another one,
Speaker 1: a blue versus yellow one that fires more when things
Speaker 1: are yellow and less when things are blue. So instead
Speaker 1: of happening like three dimensional information, our nerves have figured
Speaker 1: out a way to incorporate this in just two dimensions,
Speaker 1: like a green versus red axis and a blue versus
Speaker 1: yellow axis. It's still pulled out of the same cones,
Speaker 1: but it's a little bit of processing there to like
Speaker 1: convert it into this red versus green and blue versus yellow.
Speaker 2: I think you're talking about what happens after it hits
Speaker 2: your optic nerve and maybe after it goes up into
Speaker 2: your like visual cortex, right, you're talking about like, you know,
Speaker 2: maybe your brain or evolution said, you know, maybe we
Speaker 2: don't need three signals to figure out what color thing
Speaker 2: the banana is or whether that's a spotted leopard or not. Like,
Speaker 2: maybe we can just instead of having three variables, maybe
Speaker 2: we can just do with two variables, and maybe that's
Speaker 2: more efficient and faster and just enough to survive.
Speaker 1: Yeah, exactly. I'm not exactly sure where this happens, and
Speaker 1: you know where the brain technically ends and the optic
Speaker 1: nerve begins. But yeah, this is part of the processing
Speaker 1: that happens in your brain. This is opposing neuron theory,
Speaker 1: and that means something really interesting because it means there's
Speaker 1: a little bit of a loss of information, and it
Speaker 1: means that there are some colors which now cannot be
Speaker 1: described in this two dimensional plane. For example, a mixture
Speaker 1: of green and red. You have this one opposing neuron
Speaker 1: which is supposed to fire more if it's red and
Speaker 1: less if it's green. What does it do if you
Speaker 1: send it red and green? Right? Does it fire more
Speaker 1: for the red and fire less for the green. It's
Speaker 1: an ore system. It can tell you whether this light
Speaker 1: is red or is green. There's no response that that
Speaker 1: neuron can make that says I see red and green.
Speaker 2: Wouldn't it fire like somewhere in between? Like neurons and
Speaker 2: code things by the frequency at which they, you know,
Speaker 2: send signals, right, like little like Morse codes. So if
Speaker 2: it's like doing red and for green, wouldn't like a
Speaker 2: mixture give you something in between?
Speaker 1: You can see a color that's between red and green,
Speaker 1: But you can't see like intense red and green simultaneously.
Speaker 2: Oh, you're talking about the intensity of things, not like
Speaker 2: which frequencies are present.
Speaker 1: It's also true if this is fairly dim. But what
Speaker 1: you can see is a color between red and green. Right,
Speaker 1: If you see like something on the spectrum that's between
Speaker 1: red and green, it's like a yellow, then you can
Speaker 1: see that, and the response of the neuron will be
Speaker 1: between its response for red and for green. If you
Speaker 1: shine pure green and pure red on it. It's supposed
Speaker 1: to both trigger it and inhibit it, and it doesn't
Speaker 1: know how to communicate that there's no place on its
Speaker 1: response that means green and red.
Speaker 2: Now, as you said, this is a theory, are there
Speaker 2: experiments back it up? Or like, do we know where
Speaker 2: in the brain this is happening.
Speaker 1: We don't know where in the brain this is happening.
Speaker 1: And there's a controversial set of experiments. People were like,
Speaker 1: is it possible to see these things? What happens if
Speaker 1: you put like strips of color near each other and
Speaker 1: ask people to like focus on the line between them.
Speaker 1: So they have these experiments that did originally in the
Speaker 1: eighties where they put like strips of blue and strips
Speaker 1: of yellow next to each other, or strips of red
Speaker 1: and strips of green next to each other, and ask like,
Speaker 1: what do you experience right at the edge? You know,
Speaker 1: where you're seeing like red and green at the same time.
Speaker 1: So there's this paper in eighties by these two guys,
Speaker 1: Crane and the Piantanita, and they claim to see these
Speaker 1: impossible colors. They ask people to describe what color they
Speaker 1: were seeing at the boundary, and it was like indescribable,
Speaker 1: and so this paper was really controversial for a long time.
Speaker 1: And then there were experiments two decades later at Dartmouth
Speaker 1: in the mid two thousands that sort of disputed these
Speaker 1: results and said, like, hmm, maybe people are just seeing
Speaker 1: sort of like an intermediate color. They're not simultaneously experiencing
Speaker 1: what happens when you have red and green photons. It's
Speaker 1: just sort of like hard to describe. So this controversy
Speaker 1: in the literature about whether this theory is right. There
Speaker 1: are other theories of how we experience color and whether
Speaker 1: it's possible to see these colors in some way.
Speaker 2: So what do you mean by possible colors? You're talking
Speaker 2: about like combinations of color that we can experience, Yeah, exactly,
Speaker 2: that maybe our optic nerves are picking up because they're
Speaker 2: definitely picking up something, but we just because of the
Speaker 2: way that our brains have maybe streamlined and gotten rid
Speaker 2: of certain information that doesn't think it needs now we
Speaker 2: have kind of blind spots in the color spectrum.
Speaker 1: Yeah exactly. And I read a really fascinating paper that
Speaker 1: suggested you might be able to experience this if you
Speaker 1: can come up with a way to like differently trigger
Speaker 1: different parts of your optic nerve. Like if you could
Speaker 1: get some of these opposing neurons to respond to the
Speaker 1: green light and some of them to respond to the
Speaker 1: red light, then instead of all sending the same signal,
Speaker 1: you'd have some sending the green signal and some sending
Speaker 1: the red signal, both intensely, and then maybe your brain
Speaker 1: would know how to interpret that, and we'd give you
Speaker 1: this experience of this red green combination. That's one theory,
Speaker 1: And people argue, like, maybe that's what was happening in
Speaker 1: the eighty three experiments, that they somehow like parts of
Speaker 1: it were triggering this part of your nerve and other
Speaker 1: parts are experiencing other parts of the nerve. But yeah,
Speaker 1: it's about these mixtures of colors that we can't see.
Speaker 1: We can see all the pure colors, but these mixtures
Speaker 1: of colors we can't see.
Speaker 2: Well, I guess you would see them, you just wouldn't
Speaker 2: be able to maybe tell them apart from some of
Speaker 2: the primary colors.
Speaker 1: Perhaps this is novel color, which is a mixture of
Speaker 1: these two which we do not have an experience of.
Speaker 1: Because we think that the sensory mechanisms and the optical
Speaker 1: nerve processing can't carry the information to describe it. The
Speaker 1: loss of information means there's no way to encode it
Speaker 1: basically in those signals.
Speaker 2: Now, do these impossible colors have a specific frequency or
Speaker 2: would you call it a different color because it's a
Speaker 2: mix of different frequencies.
Speaker 1: Yeahs, see that's fascinating because we think about color as
Speaker 1: associated with the frequency spectrum, right, and so pure frequencies
Speaker 1: we think of as pure colors, and that makes sense.
Speaker 1: But here we're talking about combinations of different frequencies, like
Speaker 1: shooting red and green photons or blue and yellow photons
Speaker 1: at you at the same time. And so that's why
Speaker 1: I think it's helpful that separated the question of frequency
Speaker 1: and color, because color is what you experience in your mind,
Speaker 1: and it's not always connected to just one frequency. Like
Speaker 1: this red green color, whatever it is, that would be
Speaker 1: an experience in your mind, your brain's interpretation of seeing
Speaker 1: both red frequency photons and green frequency photons at the
Speaker 1: same time. You wouldn't experience red, you wouldn't experience green,
Speaker 1: you'd experience some red green thing we don't have a
Speaker 1: word for.
Speaker 2: I guess it kind of goes back to the question
Speaker 2: of like what is yellow like If we have sensors
Speaker 2: that the tech red, blue, and green. What is yellow?
Speaker 1: Yeah, if you just think about the spectrum, right, yellow
Speaker 1: is the color that triggers the green and the red
Speaker 1: about the same amount and doesn't trigger the blue.
Speaker 2: Like there's a specific frequency that will do that, right,
Speaker 2: I imagine mm hmm. Now you could call that frequency yellow.
Speaker 2: But you can also kind of fool the eye into
Speaker 2: thinking of yellow by mixing frequencies. That's kind of what
Speaker 2: your TV and your phone screen do.
Speaker 1: Yeah, this is specific frequency range that we know triggers
Speaker 1: the experience of yellow in your minds five hundred and
Speaker 1: seventy to five and eighty animeters. Absolutely, and you know
Speaker 1: the same way that there's like a cyan and there's
Speaker 1: a purple. You don't have a special cone for these things.
Speaker 1: There are brain creating an experience for this whole range
Speaker 1: of possible signals that it's getting.
Speaker 2: Right, And you can sort of fold it into thinking
Speaker 2: of yellow by mixing frequencies, right. I mean like in
Speaker 2: your TV or your phone screen, there's only like three
Speaker 2: kinds of LEDs in it, right, There's red, green, and
Speaker 2: yellow ones. And so when you look at something yell
Speaker 2: on your phone, it's not actually shooting yellow light, shooting
Speaker 2: some combination of red, blue, and green that's making your
Speaker 2: brain think it's yellow. But there's also a frequency that
Speaker 2: wouldn't trigger that same Oh that's yellow. Anyways. The point
Speaker 2: is that there are combinations of frequencies that maybe our
Speaker 2: brains are not designed to like trigger your consciousness of them.
Speaker 1: Yeah, exactly. There should be a unique experience for those combinations,
Speaker 1: but the brain has nobody interpret it because it doesn't
Speaker 1: get a unique signal for those combinations. So we even
Speaker 1: like developed a unique experience.
Speaker 2: It's like you're blind to those colors kind of mm hmm, yeah,
Speaker 2: like it just looks red to you. You're like Stanford,
Speaker 2: Harvard the irvine. I don't know, mm, it could be
Speaker 2: any athlete.
Speaker 1: There's two other sort of ways to think about impossible
Speaker 1: colors as well. There are colors that can't be generated
Speaker 1: by any physical source, and then there's these things they
Speaker 1: called chimerical colors.
Speaker 2: Interesting. All right, let's get into those impossible to make
Speaker 2: colors and dig into what that means. But first let's
Speaker 2: take another quick break. Are we getting very colorful today?
Speaker 2: Looking at all of the rainbow of ideas around the
Speaker 2: concept of color and how we perceive it, and what
Speaker 2: is a color anyway, and what color is your been
Speaker 2: in it as well?
Speaker 1: Hey that's a personal question, man.
Speaker 2: WHOA Well, you just got really really purple there. I
Speaker 2: wasn't even thinking about that. I see what's on your mind,
Speaker 2: Daniel m lunch. Oh that's even racier.
Speaker 1: Let's steer back to physics.
Speaker 2: But we talked about how maybe there are combinations the
Speaker 2: frequencies of light that we can't see, because really color
Speaker 2: is our experience of how light hits her eye and
Speaker 2: sometimes sets of specific frequency maybe that's sometimes that's a
Speaker 2: combination or the absence of certain frequencies. So color is
Speaker 2: a complicated thing. But there are maybe combinations of frequencies
Speaker 2: that we our brains are just not equipped to deteg
Speaker 2: unless maybe you're maybe trained to see them, or maybe
Speaker 2: you're one of these people born with extra sensors.
Speaker 1: Right, Yeah, it could be. And in the end, we
Speaker 1: don't know what other people experience. We can just ask
Speaker 1: them to compare previous experience to current experience or to
Speaker 1: some references, but we can't, you know, cross correlate across brains.
Speaker 1: We don't know how to extract from inside the brain
Speaker 1: the actual encoding of these things and interpret it in
Speaker 1: any sort of objective way map from one brain to another.
Speaker 1: In the end, it's frustrating, but we can try to
Speaker 1: reverse engineer the system and think about ways to experience
Speaker 1: like weird colors or things that we can't experience. That's
Speaker 1: a lot of fun. And the system, the way it works,
Speaker 1: because it has these overlapping responses, also creates these things
Speaker 1: called imaginary colors, colors not that we can't experience, but
Speaker 1: that no physical source could generate.
Speaker 2: Well, yeah, I think that's a question that I have
Speaker 2: from the beginning. Are there colors that are impossible to make?
Speaker 2: But I guess to be clear, all colors are possible
Speaker 2: in the universe, right, Like you can always stretch light
Speaker 2: to be a certain color infinitely with infinite precision in
Speaker 2: the universe.
Speaker 1: Right, Yes, all frequencies of light can exist out there
Speaker 1: in the universe. But remember color is our experience in
Speaker 1: the mind, and it's this interpretation of the the red, green,
Speaker 1: and blue cones and then perhaps through these opposing neurons.
Speaker 1: But because those things overlap, there's a question of like
Speaker 1: what would happen if you only triggered the green neuron
Speaker 1: right now, the green neuron and the red neuron are
Speaker 1: almost overlapping. They're almost identical, Like there's a very small
Speaker 1: shift between them. So any physical photon that hits your
Speaker 1: eyeball that triggers the green is very likely going to
Speaker 1: trigger also some red ones. So you shoot like pure
Speaker 1: green light at somebody's eyeball, some of those red cones
Speaker 1: are also going to get triggered.
Speaker 2: Right because I think what we said before is that
Speaker 2: our cones are not perfect, right, Like, they don't just
Speaker 2: respond to one frequency. They respond to a range of frequencies,
Speaker 2: and in our eyes, those ranges kind of overlap, So
Speaker 2: there are some frequencies that will activate both yes.
Speaker 1: And the red and the green in particular are very
Speaker 1: close to each other. They respond almost the same way
Speaker 1: to different frequencies, and so like if you shoot something
Speaker 1: right in the middle of the green, then the green
Speaker 1: cone is always going to respond and the red cone
Speaker 1: is going to respond. Like ninety percent of the time
Speaker 1: was like further shifted down. But it makes you wonder,
Speaker 1: like what would happen if you could somehow just tweak
Speaker 1: the cones. Don't worry about the light you're shooting at
Speaker 1: it just somehow get only the green cone to respond
Speaker 1: without the red cone responding.
Speaker 2: Like what would happen in your brain?
Speaker 1: Yes, they call this hyper green, like the greeniest green
Speaker 1: that you could experience without any pollution from the red.
Speaker 1: In reality, it's essentially impossible to generate this using photons
Speaker 1: because all these photons will also stimulate that red cone.
Speaker 2: Oh you're talking about like it's an impossible experience of
Speaker 2: that color.
Speaker 1: We don't know that it's impossible. Like technically, if I
Speaker 1: attached little electrodes to all the nerves behind the green
Speaker 1: cones and stimulated them, then you would have this experience.
Speaker 1: But I can't create a photon that would do the
Speaker 1: same thing.
Speaker 2: You mean, like, you can't create a photon that will
Speaker 2: ignore the red cones, Yeah, and only hit the green
Speaker 2: cone exactly. Well, less you could somehow aim them really well.
Speaker 1: Yeah, exactly, super precise lasers in the back of your
Speaker 1: eye only hit those green cones. So it's possible, then, well,
Speaker 1: we think it's possible for it to happen. It's just
Speaker 1: that there isn't a physical source we could make that
Speaker 1: can do that. Yes, but that's the experience of hyper green.
Speaker 2: Right right, And it's probably the color of like mountain dew,
Speaker 2: or like if you took a green highlighter and like
Speaker 2: paint is sear the back of your eyeball.
Speaker 1: Yeah, so those are imaginary colors. Then there's another really
Speaker 1: fun kind of color that you actually can experience.
Speaker 2: But I mean it's not just green, right, and it's
Speaker 2: like all of them right, Like, it's probably possible to
Speaker 2: create a hyper blue or a hyper red.
Speaker 3: Mm hm.
Speaker 1: It's trickier with green and red because those two response
Speaker 1: curves are basically on top of each other, so it's
Speaker 1: harder to separate. Blue is further away, so it's possible
Speaker 1: to experience a purer blue than it is red or green.
Speaker 1: But in principle, yes, these same things are true. Even
Speaker 1: blue photons will stimulate a fraction of the green and
Speaker 1: red cones.
Speaker 2: All right, So that's one kind of impossible color. You said,
Speaker 2: there's another kind.
Speaker 1: There's another category. These are called chimerical colors. These are
Speaker 1: colors you experience if you change the way that your
Speaker 1: cones respond. Remember, these are little biological machines and they
Speaker 1: can sort of get tired. You know that if you
Speaker 1: look at a really bright light and then look away,
Speaker 1: for example, you still see it, right, that's because your
Speaker 1: cones are tired and they're responding differently. Now there's something
Speaker 1: like residual effect there. So for example, if you stare
Speaker 1: at like really bright yellow light, it sort tires out
Speaker 1: these opposing neurons. Then if you close your eye or
Speaker 1: you look at something really really black, then you see
Speaker 1: this blue response. There's no blue there. You're seeing a
Speaker 1: reaction to tiring out your blue yellow neurons. And so
Speaker 1: what you see is this super dark blue, this blue
Speaker 1: that you otherwise could not experience because to experience it,
Speaker 1: you'd need to receive a bunch of blue photons and
Speaker 1: that would make it brighter. So you see this like
Speaker 1: impossibly dark blue.
Speaker 2: Whoa couldn't you just sit in a room and shoot
Speaker 2: blue photons at my eyeball?
Speaker 1: You could do that, but then receiving those photons would
Speaker 1: create an experience of a brighter blue, and if you
Speaker 1: dial it down eventually you just wouldn't see anything. You
Speaker 1: just see black. So this is like a blue you
Speaker 1: can experience without receiving any photons.
Speaker 2: Right, because you're basically doing the same thing as these
Speaker 2: imaginary colors, right, you're sort of like knocking out your
Speaker 2: perception of certain rods and cones right exactly.
Speaker 1: And this is actually pretty easy to do. You just
Speaker 1: go to like Wikipedia and google chimerical colors. They have
Speaker 1: these templates, and you like staring a yellow dot and
Speaker 1: then look at a black field and you can see
Speaker 1: this blue which is different from just like a really
Speaker 1: really dark blue. It's fascinating. It's called sticky and blue.
Speaker 2: Whea, it's wild to think that, Like, if I'm just
Speaker 2: staring at something yellow, like my brain and my eyeballs
Speaker 2: and brains are constantly going yellow yellow, yellow, yell ye yellow,
Speaker 2: and eventually just like I give up, forget it.
Speaker 1: Yeah, then they're tired, and then the blue one's out right,
Speaker 1: and then they're sort of like leaning or they're biased
Speaker 1: against it. They're like exhausted, the yell the like, don't
Speaker 1: show me any more yellow. We're leaning blue for a while,
Speaker 1: and they're basically sending you blue information even though there's
Speaker 1: nothing there. And so because there's no brightness to it,
Speaker 1: but you're getting blue, your brain is like, well, I
Speaker 1: got to give you something blue, but there's no brightness there,
Speaker 1: So what do we do. Let's make the darkest blue
Speaker 1: we can. So it's a very deep blue.
Speaker 2: Does that mean that if I stare at a banana
Speaker 2: long enough, it'll eventually look blue.
Speaker 1: I think it means if you stare a banana long
Speaker 1: enough and close your eyes, you'll see an impossibly blue banana.
Speaker 2: I guess you won't see it because you won't be
Speaker 2: like experiencing photons from the banana. It'll be like sort
Speaker 2: of this lingering memory in your visual cortex of a
Speaker 2: blue banana.
Speaker 1: Yeah, you'll be experiencing a deep blue banana even though
Speaker 1: you're not getting blue photons from the banana.
Speaker 2: From the banana, Yeah, yeah, I guess it's all because
Speaker 2: we have this kind of flawed bio logical machinery that's
Speaker 2: trying to interpret with the frequency that we see in
Speaker 2: the world. But maybe through revolution, it's done it in
Speaker 2: a week way where you have these weird effects right
Speaker 2: where we can see certain combinations or you know, we
Speaker 2: see residual colors.
Speaker 1: Yeah, all of these colors in the end are brain's
Speaker 1: interpretation of these signals, signals that are typically generated by
Speaker 1: this experience or that experience. Back for in the corners
Speaker 1: of this and the limitations of it, we can try
Speaker 1: to get some understanding of what it means to see
Speaker 1: color what it tells us about what's happening out there
Speaker 1: in the universe.
Speaker 2: Because I guess you know, as physicists or as scientists,
Speaker 2: we can think about all the different frequencies of light.
Speaker 2: But maybe if you're like a simple creature, you don't
Speaker 2: need to know all that information, Like you don't need
Speaker 2: to know whether something's ten point seven herds. You just
Speaker 2: need to know, like, is this thing going to eat
Speaker 2: me or not? That's in front of me? Is it red?
Speaker 2: Is it the red kind that's going to eat me?
Speaker 2: Or is it the blue kind that's going to not
Speaker 2: eat me?
Speaker 1: Yeah, exactly, And that's why some bees can see into
Speaker 1: the ultraviolet because they have to despot the right kind
Speaker 1: of flower. For example. That's probably why manti strimp have
Speaker 1: super impressive hardware for ultrafast processing of this color and
Speaker 1: then like mostly waste that information because the don't really
Speaker 1: need to know specifically, they just needed fast processing.
Speaker 2: Now, if a manta shrimp looked at a banana, would
Speaker 2: it think it's a banana?
Speaker 1: That's another philosophy of paper I want.
Speaker 2: To write over to think, Oh, that's a nice digim
Speaker 2: blue banana.
Speaker 1: What is it like to be a manta strip eating
Speaker 1: a banana.
Speaker 2: Nobody knows that's the right feel. I'm pretty sure nobody
Speaker 2: has published that paper.
Speaker 1: I'm going to get on it.
Speaker 2: All right. Well, the interesting discussion here about what color
Speaker 2: is and what we can perceive. And you know, it
Speaker 2: has a physical basis, but our brains the way it's evolved,
Speaker 2: don't experience maybe the world the way physics has built it.
Speaker 1: And it's important to remember that our experience in the
Speaker 1: universe is always one step divorced from the reality of
Speaker 1: the universe, which is, in the end, our interpretation of
Speaker 1: a model we are building in our brain. Our a
Speaker 1: direct experience is what we actually can count on. Everything
Speaker 1: else is our interpretation.
Speaker 2: Yeah, and if that makes you red with anger or
Speaker 2: blue with sadness, just close your eyes.
Speaker 1: Don't yellow at us.
Speaker 2: Yeah, imagine a more beautiful universe of colors. All right, Well,
Speaker 2: we hope you enjoyed that. Thanks for joining us. See
Speaker 2: you next time.
Speaker 1: For more science and curiosity, come find us on social
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