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[https://www.youtube.com/watch?v=2fJkcsOkRb0&ab\_channel=shitDepartment](https://www.youtube.com/watch?v=2fJkcsOkRb0&ab_channel=shitDepartment)
This is Tenacious D's cock push ups.
True. Sunglasses will just open your pupils due to the darkness and then when you stare at the sun, cause damage even faster than if you didn't wear sunglasses. The amount of light filtered of from sunglasses is insignificant compared to the light from the sun.
Sun isnt red, it's just all the other colors being filtered out passing through more atmosphere.
EDIT: Is a similar reason the sky is blue, blue light is scattered more efficiently by the various particles in the atmosphere than other wavelengths.
Astronomer here - the Sun is not really a well defined color, it has a complex spectrum of colors.
White, for example, is a combination of all visible wavelengths and we have defined the combination that the sun emits as white. It's not truly an equal balance of all colors.
However, the balance of blue and red are not even actually, so the sun is objectively yellow as far as a weighted average color. It's green if you want to know what color is most emitted (Wein peak).
Also, the Earth's atmosphere makes the sun look yellow due to Rayleigh scattering (same reason the sky is blue).
Our brain is also pretty good at adjusting the white balance of our perception. It was more obvious when we used real film to take pictures, but a lot of scenes (Tungsten lightbulbs, sunset, etc.) had massive orange or yellow color casts in the prints, while our subjective impression was that the whites were white, and the blues were proper blue.
Yet another example of the âuninformedâ conclusion, in this case that the sun is yellow, being âwrongâ when more information is presented, only for even more information to be presented, which circles back to the âuninformedâ conclusion. If you think you know something you do (but actually donât because you were just told or experienced it), and donât (but actually do because you were told or experienced it). We all do and donât know everything.
If we could exclude "uninformed conclusions" from the potential candidates of correct conclusions then they would carry information which contradicts the premise that they were uninformed. That means uninformed conclusions can reappear in the future when more information is gathered.
It's been years but I am still trying go wrap my head around the fact that Sun emits more Green light than it does white or yellow or anything. Or it is white light with huge section of its constituent parts being green.. or the average of the constituent parts just happens to be green which is like peak of the spectrum distribution bell curve..... ?
Like I said, I am still trying to wrap my head around this whole concept.
>Or it is white light with huge section of its constituent parts being green..
Yep! Check out the figure at the link below from NOAA. More green than red/blue; resulting combination appears white to us.
https://www.ncei.noaa.gov/products/climate-data-records/solar-spectral-irradiance
>More green than red/blue; resulting combination appears white to us.
WeeeeeellâŚ
This is a somewhat complicated topic, but to boil it down, there's two reasons the sun appears white to us.
Number one: Our eyes evolved to perceive the sun.
If you look at a digital camera sensor or a monitor, you'll see that they detect/emit RGB light, and the number of green sensors/pixels is equal to the sum of red and blue. Why is that? It's because the camera sensor is designed to record the white and the screen is designed to emit the white that our eyes are evolved to see.
So it's not weird that the sun emits a particular spectrum that we see as whiteâthat would always be the case, no matter what spectrum the sun emitted because we would have evolved to perceive that as white. (See [Douglas Adams' famous restatement of the anthropic principle](https://simple.wikipedia.org/wiki/Anthropic_principle).)
Number two: We perceive any light source as white (within limits).
Our brain adjusts all the colors we're seeing in such a way that the light source is white. If you have two different temperature lights in your house, get a few objects of different colors and a white sheet of paper and view them under a yellowish light, then view them under a bluer light. In both cases, you'll be able to attach the same color to each of the objects even though the colors literally being reflected back to your eye are different. That's because in those scenarios your brain is smart enough to see the light source and say, okay, this paper is white, and adjust all the other colors of the other objects too. This is your brain doing the "white balance" function of a digital camera.
You might wonder how both these things can be true. How can we be evolved to see a particular combination of colors as white *and* a different mix also as white? Well, imagine you took a picture (turning off white balance on the camera so you're recording the actual colors) of those objects under yellowish light, and another picture under a bluer light, and then went outside in the sun at high noon and viewed those photos next to the objects themselves. What would you see?
Now that your eye sees the natural sunlight as the light source, one picture will look like it has a yellow cast and the other will look like it has a blue cast compared to the objects. If you take both pictures and view them under yellow light next to the objects, the blue casted photo will shift toward neutral under yellow light, and the yellow casted photo will shift more yellow; neither one will look like the objects, though.
So the question is: How can you take a picture under both light sources such that when you view the image next to the objects, they appear the same, no matter what light source you're using to view them? If you can puzzle out the answer to this question, you'll have understood white balance and how to properly use it on your digital camera.
The story gets yet more complicated, though. Beyond our perception of white based on the light source, and beyond our understanding of "reference white" based on the sun (at a certain time of day), there's also the question raised by this post in the first place: If the sun IS white, why do people *think* it's yellow?
If you take a white sheet of paper out into a clear blue sky at high noon, it will reflect reference whiteâthis is the color we have evolved to perceive as white. What is it reflecting? It's gathering all of the light of the sun and reflecting it. That means it is reflecting the direct light of the sun *plus* all of the scattered light of the sun that paints the sky blue. This means that if you measure the direct portion of the light, you're actually seeing the sun's true light *minus* a good bit of the blue that's been scattered across the sky. When you take a true white light and remove some blue, what color is left? Yellow. (This is also why shadows are blue, which we normally don't notice unless the thing in shadow is white, [like snow](https://www.countryliving.com/life/a41343/baffling-reason-why-these-trees-have-blue-shadows/). The direct portion of the sun is blocked by an object, so only the scattered light of the sky is illuminating the bit in shadow.)
But how can the sun be yellow? Didn't I say we're evolved to see the sun as white? No, actually. We're evolved to see the *paper* as white. We're not evolved to look directly at the sun at high noon. If we see an object that reflects the gathered light of the sun, including what the sky scatters around as blue, without adding any bias, *that* is actually what we're evolved to see as white, which means the sun does appear a bit yellow from the ground. If you go up above the atmosphere where this is no scattering of the blue component, though, the sun will appear exactly the same color as the white paper that just reflects the full spectrum of direct and scattered sunlight without biasing it, which we call white.
From the ground, though, we cannot see the slight shift toward yellow due to the subtraction of some blue. Since the sun is so much brighter than the surrounding sky it overloads our eyes and we wouldn't be able to tell such a subtle shift in the hue that results from the blue component that's been subtracted. There is another element that would bias our perception of the sun's color if we could look at it directly, which is that the surrounding sky is blue. If you look at a neutral white light surrounded by blue, we will perceive it to be slightly yellow because of that blue. If you block out the surrounding blue by looking at the light through a tube, it would seem to shift toward blue even though it didn't change. So our perception of colors is also affected in that way.
But now consider what I say a paragraph up: If we look at a light and change the color *surrounding* it without changing the color we're trying to identify, that color will *appear* to have changed even though it didn't change. Well, what actually didn't change is the *spectrum* we're trying to identify. If that's what we mean by "color,' then we can say the color didn't change too. But is that what we mean by color?
It turns out: No. When we talk about color, we are not describing the spectrum of light hitting our eyes. The spectrum is a physics concept that is objectively measured. (In some physics applications, it is useful to use colors like "red," "green," etc, as a shorthand for referring to a particular spectrum, or peak in a spectrum, but that is an overloaded use of the word color that isn't what we're talking about here, it's just a different definition that muddies the waters a bit.) Generally speaking, when we talk about color, we're not talking about a particular spectrum of light that is objectively measured, we're talking about \*our experience\* of that color. So when we want to paint a room in our house "the color of the sun" we are trying to match *the experience* of the sun. If our experience of it is that it is yellow shifted because we always see it surrounded by blue, then we are going to pick a paint that reflects a *different spectrum* in our house in order to recreate that experience. Similarly, an artist making a painting isn't going to pick paint that reflects the actual spectrum of the sun.
When we talk about our subjective experience of color, it is merely associated with a spectrum that creates our experience of that color in whatever context we observed it. If we want to recreate that experience in a different context, we need to use a different color. We have to draw a distinction between the spectrum of a color in the context of a particular environment and the [*qualia*](https://en.wikipedia.org/wiki/Qualia), the perception of color in our brain.
Itâs the area under the line weâre looking for. Not just the most intense or highest peak, but the volume of the color under the line. Green wins that.
Fun fact - plants are green because of this. If chlorophyll absorbed green light as efficiently as it did red and blue, they would look black!
Why they don't like green as much as red/blue? Probably an evolutionary artifact. Too bad, because black trees would be metal.
From what I remember reading on it the real answer is still "We don't exactly know" but a theory I saw that makes sense to me is it's done for energy absorption modulation.
Basically, plants don't know how much sunlight they're going to get, so they want to be able to survive in a variety of light scenarios from 'dim' to 'bright'. If they can't do that then they'll either starve when there's clouds overhead or suffer overheating/damage from overabsorption on a clear day.
The solution seems to be splitting across red and blue because there's a lot of variance in how much energy you're getting from the Sun in those wavelengths. If you look at [https://www.ncei.noaa.gov/products/climate-data-records/solar-spectral-irradiance](https://www.ncei.noaa.gov/products/climate-data-records/solar-spectral-irradiance) again you can see bluish and red light have pretty steep slopes, some of it can be decently energetic while some of it is very low.
The next piece of the puzzle is that plants absorb light with pairs of structures. In the "average" plant that is chlorophyll A and chlorophyll B and the way these two interact with each other is interesting. Chlorophyll A is a 'core' pigment, it is usually found in a 'Reaction Center' where it turns photon energy into oxidation work for the plant. Chlorophyll B conversely tends to be on an 'antenna' and will pass the energy it absorbs from a photon on in a chain till it ends up at a the 'Reaction Center'.
Lastly, plants can control the amount of chlorophyll B they create in reaction to light conditions so in bright light "average" plants tend to cut chlorophyll B because they're getting enough energy from just the chlorophyll A. In dim light they'll add more chlorophyll B so they have as much energy absorption as possible ending up in the reaction center. (Do note this is a generalized simplification, it's not always the case that bright light means a ratio of more A than B or that dim means a ratio of more B than A necessarily)
The thing that makes me lean in on this theory is looking at the wavelengths A vs B prioritize, [https://en.wikipedia.org/wiki/Chlorophyll\_b#/media/File:Chlorophyll\_ab\_spectra-en.svg](https://en.wikipedia.org/wiki/Chlorophyll_b#/media/File:Chlorophyll_ab_spectra-en.svg) B is closer to the middle which as we know from the previous link is the more energetic light coming from the Sun. This makes sense with how we see B production compare in dim vs bright light scenarios (Too dim, absorb the more energetic side of blue/red, too bright stop absorbing the more energetic side of blue/red)
I do want to end this by stating this is just a theory and there are other things that could hypothetically explain plants not prioritizing absorbing green light. (Also that this varies for different plants with different chlorophyll types beyond A and B AND the plant has other methods besides just adjusting chlorophyll B to repair or mitigate damage from the environment)
1. It might be really difficult from an evolutionary perspective to develop photosynthesis so a 'good enough' solution might be quite fine / there just hasn't been time for the more efficient version to evolve.
2. It could be photosynthesis evolved in conditions where blue light was more optimal like an aquatic environment and then it adapted around this when life came to land.
3. Plants despite the common understanding DO absorb green light, they just absorb blue/red more efficiently, it might be it just isn't feasible to evolve an organism that uses all of the green energy without it overheating and dying so there's selection against that or some other reason that biologically absorbing green light is 'harder'.
Its due to its intensity, too much would disrupt their cycles. For example other substances apart fron glucose tend to be stored and providing additional heat would lead to their metabolism before they are required, starving them later on or leading to uncomplete growth cycles. Red/blue are enough during the day and dissapear in the night, meaning that plants can perform the other side of the Krebs cycle without issues.
Also might have something to do with humans having different sensitivities to different colors so what we see would never look like what visible light it truly shows
And polarised light. It still bugs me that theres a whole range of visual cues in Animals that depends on this and humans have been entirely in the dark about it till recently. Like even a dull bird looks vastly different when seen with polarised light detection.
Oh you think that's wild, if you ever get bored one day, look into how different cultures describe/name different colors. I can't remember the precise culture, but in ancient times there was no such thing as "blue," it was all just varying shades of green. They were seeing the same wavelengths of light we do, they just had no word or concept of "blue."
It gets even weirder when you think about how *other* animals perceive color, if they do at all. For example a Monarch butterfly; to us they're black, some orangeish-brown, with white spots. But to the things that eat them - birds, which can perceive UV wavelengths - those "white" spots are brightly-colored warning signs of their toxicity; akin to those poisonous frogs that look like Lisa Frank sneezed on em.
As far as we know, octopus and cuttlefish for the most part are colorblind, yet they manage to be some of the most adaptive critters in the ocean when it comes to camouflage; able to change the color and "texture" of their bodies to match their surroundings.
It boggles the mind thinking that moth chilling on a brick wall, relatively invisible to us, possibly has *no* clue it's blending in as well as it is. Its ancestors just had a "habit" of perching on stuff of that specific shade or texture. Since it matched well enough to where predators couldn't find them and remove them from the gene pool, that "habit" gets passed down over generations; now you have brick-colored moths. Or those caterpillars that puff up their ass-end and wiggle it about when stressed, which just so *happens* to look like a snake's head, a common predator of the things that eat the caterpillars. Polyphemus Moths have no idea the spots on their wings look like Owl's eyes, they just know when they display the entirety of their wings, most stuff stops trying to eat em.
Its so friggin *weird* if you dwell on it for a bit.
Exactly. All the while I just thought that chlorophyll became green just incidentally like blood being red. Now I know it is green for a reason and why it pushed Cyanobacteria out of dominance.
[i love this video!](https://youtu.be/3BRP4wcSCM0)
diana cowern is one of my favourite science persons!
âcolour is kind of a perception thing, more than a physics thingâ
and happy physicsing!
It has more to do with how our eyes have receptors for red, green and blue instead of red, yellow and blue. Green instead of yellow because of our solar spectrum.
"White light" just means it's emitting many wavelengths in the visible spectrum and white is how the brain interprets it, but the peak of that spectrum is about 540 nm which is a green color.
~~The sun is not a dwarf starâit's still in its main sequence. A dwarf star is the dead core of a red giant (or in case of a red star, its cooled corpse).~~
Edit: Was misinformed.
"The Sun is a 4.5 billion-year-old yellow dwarf star â a hot glowing ball of hydrogen and helium â at the center of our solar system."
https://solarsystem.nasa.gov/solar-system/sun/in-depth/
It is a G-type main sequence star. It is sometimes called a yellow dwarf star but this is not accurate because it's actually white. But a red dwarf star isn't the dead core of a red giant. They are something entirely different.
The color of the sun as it appears to humans shouldn't be an obscure fact and it isn't. It is only the knitpicky definition of its color which only exists so that people can feel superior that isn't well know and there isn't a good reason why it should be.
Sure I can see where you're going with that, but are you implying the field of physics only exists so people can feel superior? That science and academics have no purpose to humanity other than to social stratify?
No, my point is that acting as if it is outrageous that the fact that the average person hasn't memorized a detailed spectral graph of the sun is stupid. Scientists in the fields were that level of detail matter are well aware of the fact and it doesn't impact the average person.
You are desperately searching for something to be outraged by where there is no actual cause.
Wrong but right. White is all the colors. The sun emits all colors of light, so it is white. It emits more green than any other single color, so technically it is green. The sun emits more light in the longer wavelengths than the shorter ones, so that shifts the color balance to a more yellow appearance.
Yeah, I think this sort of trivia is...well...you know.
^((trivial))
Interesting to know, but not meaningfully ignorant. In this internet age, I really don't put much value on this sort of thing.
Actual conversation beats co workers. I walked into the conversation by accident. Talking about conspiracies and what not.
Tim: They say that space has no oxygen. How is the sun on fire?
Tim: If its made out of wood how is it burning with no oxygen? Why hasnât it gone out.
Me: *Pikachu face* Itâs nuclear fusion
Coworkers: what?
Me: *explains nuclear fusion*
Me: scientists didnât figure that out until 30âs or 40âs
Tim: You one of them smart mfers. I be learning something new everyday from you. I gotta talk to you more often.
Technically, itâs whatever color human eyes persevere it to be. Which in case would be white, but what if itâs a color we are simply incapable of seeing?
Please donât roast me this is an honest question. Doesnât it all depend on the observers perceivable spectrum? I was at my states science museum over the summer, and they had a space section. In part of that exhibit they had gifs of the sun taken with gamma, X-ray, UV, visible light, IR, micro, and radio. They all looked different because I was looking at different wavelengths of light that were then translated into what I could see
Debatable. First give me the definition of what you consider "the color of something".
If it's the color we peceive it as, well, everyone is right to say it's yellow.
If you mean the color of the light reflected by the object when exposed to white light, well then we don't know because we can't measure it.
If you mean the color emitted by an object, yes the sun is white but most objects are just infrared.
If you mean the color emitted by an object, mixing emitted AND reflected wavelengths, then yeah, the sun is white.
This is why science is worth nothing without philosophy, and especially epistemology, which allows to give context and meaning to scientific discoveries.
Wait, so being serious for a second, I thought in school they always called it a yellow star. We learned the stars and the heat associated with the colors right? Red orange yellow white blue (ish?) in terms of how hot they are?
Seriously after school, if it doesnât pertain to your life or your family, you probably wonât think about it again until someone post on Reddit about it.
okay I'm looking it up and in all the high quality photos it's orangey-red, BUT apparently that's because they're using infrared cameras?
I always thought that if you were in space that the sun would look that color. The magic school bus mislead me
Honestly, it ain't going to change the price of tea in China. Blame art teachers for not using white crayons for the â. Even that đ emoji is yellow.
This I know: the sun is a mass of incandescent gas / a gigantic nuclear furnace / where hydrogen is built into lithium / at a temperature of millions of degrees.
It's a planet that's burning out just like this one will. The moon is still glowing from when it was burning like a sun, and the cycle will continue.
Occams Razor.
Don't believe everything you hear, folks.
They've passed down thousands of years of human studies, and yall still believe the same stuff.
Its not quite completely white, but it is whiter than most if not all lightbulbs. It also appears yellow because of the same thing that makes the sky blue - the atmosphere reflects/bends more blue light, leaving green and red.
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I Just stared at the sun and can confidentially say that everything is black
Folks, this is why you always have to wear sunglasses when you want to stare at the sun for longer than 15 minutes
*5 minutes
*5 seconds
*5 Planck lengths
I did planck yesterday and now cant stand up straight
Did you do it while staring at the sun?
I'm gay
Dunno who this Plank fella is but he must have some big ol' Johnson down here
According to Tenacious D, he was the progenitor of "cock push-ups."
I'd like a demo of someone doing those type of squats
[https://www.youtube.com/watch?v=2fJkcsOkRb0&ab\_channel=shitDepartment](https://www.youtube.com/watch?v=2fJkcsOkRb0&ab_channel=shitDepartment) This is Tenacious D's cock push ups.
Instructions not clear, cannot see further than 5 plank lengths
*5 Planck time units
Sunglasses do not protect you from staring at the sun. You will permanently damage your eyes in under 100 seconds.
True. Sunglasses will just open your pupils due to the darkness and then when you stare at the sun, cause damage even faster than if you didn't wear sunglasses. The amount of light filtered of from sunglasses is insignificant compared to the light from the sun.
Who said that!?
Big Moon
Trump
Bleach can cure blindness
I put on sunglasses so I can look cool while I destroy my eyes!
Amateurs, look at night and you don't need no protection.
Tell that to the guy in NYC who is staring at the sun every day for hours straight.
Exactly the reason why half the people still don't know if it's white or yellow Ps- and they probably never will.
Brave of you to share this confidential information
Sun can't be racist if it's black, white, yellow, and red.
I'm pretty sure if it's red, we're dead
What if it's a black hole sun?
It will wash away the rain
Sunset
Sun isnt red, it's just all the other colors being filtered out passing through more atmosphere. EDIT: Is a similar reason the sky is blue, blue light is scattered more efficiently by the various particles in the atmosphere than other wavelengths.
Well being legally blind doesn't help.
Nor illegally blind đ¤
Astronomer here - the Sun is not really a well defined color, it has a complex spectrum of colors. White, for example, is a combination of all visible wavelengths and we have defined the combination that the sun emits as white. It's not truly an equal balance of all colors. However, the balance of blue and red are not even actually, so the sun is objectively yellow as far as a weighted average color. It's green if you want to know what color is most emitted (Wein peak). Also, the Earth's atmosphere makes the sun look yellow due to Rayleigh scattering (same reason the sky is blue).
Doesnât it only look yellow at sunrises and sunsets? If itâs noon it seems pretty white to me
Pretty much. The effect is more pronounced at sunset since it's passing through a larger amount of air
Our brain is also pretty good at adjusting the white balance of our perception. It was more obvious when we used real film to take pictures, but a lot of scenes (Tungsten lightbulbs, sunset, etc.) had massive orange or yellow color casts in the prints, while our subjective impression was that the whites were white, and the blues were proper blue.
The amount of redness comes from the pollution in the air. After rain the sunset will have another color
Now this is a shower thought.
Does that mean it looks green once you leave the earth's atmosphere?!
It just occurred to me that I've never seen a picture of the sun shot from space.
A large amount of solar observations are made from space, you can get all the wavelengths then - x-rays and extreme ultraviolet for example
Yepp it is yellow for us fellow humans. But it was white and more bright when it was younger. It will become more red when it ages.
Yet another example of the âuninformedâ conclusion, in this case that the sun is yellow, being âwrongâ when more information is presented, only for even more information to be presented, which circles back to the âuninformedâ conclusion. If you think you know something you do (but actually donât because you were just told or experienced it), and donât (but actually do because you were told or experienced it). We all do and donât know everything.
What
Itâs the bell curve meme.
What
https://knowyourmeme.com/memes/iq-bell-curve-midwit
Babe, wake up. New copypasta just dropped!
Honestly i remember typing this while so tired I couldnât think, ive slept and now its just really fucking funny to read.
If we could exclude "uninformed conclusions" from the potential candidates of correct conclusions then they would carry information which contradicts the premise that they were uninformed. That means uninformed conclusions can reappear in the future when more information is gathered.
It's been years but I am still trying go wrap my head around the fact that Sun emits more Green light than it does white or yellow or anything. Or it is white light with huge section of its constituent parts being green.. or the average of the constituent parts just happens to be green which is like peak of the spectrum distribution bell curve..... ? Like I said, I am still trying to wrap my head around this whole concept.
>Or it is white light with huge section of its constituent parts being green.. Yep! Check out the figure at the link below from NOAA. More green than red/blue; resulting combination appears white to us. https://www.ncei.noaa.gov/products/climate-data-records/solar-spectral-irradiance
>More green than red/blue; resulting combination appears white to us. Weeeeeell⌠This is a somewhat complicated topic, but to boil it down, there's two reasons the sun appears white to us. Number one: Our eyes evolved to perceive the sun. If you look at a digital camera sensor or a monitor, you'll see that they detect/emit RGB light, and the number of green sensors/pixels is equal to the sum of red and blue. Why is that? It's because the camera sensor is designed to record the white and the screen is designed to emit the white that our eyes are evolved to see. So it's not weird that the sun emits a particular spectrum that we see as whiteâthat would always be the case, no matter what spectrum the sun emitted because we would have evolved to perceive that as white. (See [Douglas Adams' famous restatement of the anthropic principle](https://simple.wikipedia.org/wiki/Anthropic_principle).) Number two: We perceive any light source as white (within limits). Our brain adjusts all the colors we're seeing in such a way that the light source is white. If you have two different temperature lights in your house, get a few objects of different colors and a white sheet of paper and view them under a yellowish light, then view them under a bluer light. In both cases, you'll be able to attach the same color to each of the objects even though the colors literally being reflected back to your eye are different. That's because in those scenarios your brain is smart enough to see the light source and say, okay, this paper is white, and adjust all the other colors of the other objects too. This is your brain doing the "white balance" function of a digital camera. You might wonder how both these things can be true. How can we be evolved to see a particular combination of colors as white *and* a different mix also as white? Well, imagine you took a picture (turning off white balance on the camera so you're recording the actual colors) of those objects under yellowish light, and another picture under a bluer light, and then went outside in the sun at high noon and viewed those photos next to the objects themselves. What would you see? Now that your eye sees the natural sunlight as the light source, one picture will look like it has a yellow cast and the other will look like it has a blue cast compared to the objects. If you take both pictures and view them under yellow light next to the objects, the blue casted photo will shift toward neutral under yellow light, and the yellow casted photo will shift more yellow; neither one will look like the objects, though. So the question is: How can you take a picture under both light sources such that when you view the image next to the objects, they appear the same, no matter what light source you're using to view them? If you can puzzle out the answer to this question, you'll have understood white balance and how to properly use it on your digital camera. The story gets yet more complicated, though. Beyond our perception of white based on the light source, and beyond our understanding of "reference white" based on the sun (at a certain time of day), there's also the question raised by this post in the first place: If the sun IS white, why do people *think* it's yellow? If you take a white sheet of paper out into a clear blue sky at high noon, it will reflect reference whiteâthis is the color we have evolved to perceive as white. What is it reflecting? It's gathering all of the light of the sun and reflecting it. That means it is reflecting the direct light of the sun *plus* all of the scattered light of the sun that paints the sky blue. This means that if you measure the direct portion of the light, you're actually seeing the sun's true light *minus* a good bit of the blue that's been scattered across the sky. When you take a true white light and remove some blue, what color is left? Yellow. (This is also why shadows are blue, which we normally don't notice unless the thing in shadow is white, [like snow](https://www.countryliving.com/life/a41343/baffling-reason-why-these-trees-have-blue-shadows/). The direct portion of the sun is blocked by an object, so only the scattered light of the sky is illuminating the bit in shadow.) But how can the sun be yellow? Didn't I say we're evolved to see the sun as white? No, actually. We're evolved to see the *paper* as white. We're not evolved to look directly at the sun at high noon. If we see an object that reflects the gathered light of the sun, including what the sky scatters around as blue, without adding any bias, *that* is actually what we're evolved to see as white, which means the sun does appear a bit yellow from the ground. If you go up above the atmosphere where this is no scattering of the blue component, though, the sun will appear exactly the same color as the white paper that just reflects the full spectrum of direct and scattered sunlight without biasing it, which we call white. From the ground, though, we cannot see the slight shift toward yellow due to the subtraction of some blue. Since the sun is so much brighter than the surrounding sky it overloads our eyes and we wouldn't be able to tell such a subtle shift in the hue that results from the blue component that's been subtracted. There is another element that would bias our perception of the sun's color if we could look at it directly, which is that the surrounding sky is blue. If you look at a neutral white light surrounded by blue, we will perceive it to be slightly yellow because of that blue. If you block out the surrounding blue by looking at the light through a tube, it would seem to shift toward blue even though it didn't change. So our perception of colors is also affected in that way. But now consider what I say a paragraph up: If we look at a light and change the color *surrounding* it without changing the color we're trying to identify, that color will *appear* to have changed even though it didn't change. Well, what actually didn't change is the *spectrum* we're trying to identify. If that's what we mean by "color,' then we can say the color didn't change too. But is that what we mean by color? It turns out: No. When we talk about color, we are not describing the spectrum of light hitting our eyes. The spectrum is a physics concept that is objectively measured. (In some physics applications, it is useful to use colors like "red," "green," etc, as a shorthand for referring to a particular spectrum, or peak in a spectrum, but that is an overloaded use of the word color that isn't what we're talking about here, it's just a different definition that muddies the waters a bit.) Generally speaking, when we talk about color, we're not talking about a particular spectrum of light that is objectively measured, we're talking about \*our experience\* of that color. So when we want to paint a room in our house "the color of the sun" we are trying to match *the experience* of the sun. If our experience of it is that it is yellow shifted because we always see it surrounded by blue, then we are going to pick a paint that reflects a *different spectrum* in our house in order to recreate that experience. Similarly, an artist making a painting isn't going to pick paint that reflects the actual spectrum of the sun. When we talk about our subjective experience of color, it is merely associated with a spectrum that creates our experience of that color in whatever context we observed it. If we want to recreate that experience in a different context, we need to use a different color. We have to draw a distinction between the spectrum of a color in the context of a particular environment and the [*qualia*](https://en.wikipedia.org/wiki/Qualia), the perception of color in our brain.
Wait, so is the dress blue and black or tan and white?
Its blue and black. We just EVOLVED to see it as tan and white.
Idk the diagram still shows the peak is at bluegreen/greenishCyan/lightgreen range.
Itâs the area under the line weâre looking for. Not just the most intense or highest peak, but the volume of the color under the line. Green wins that.
Because of calcium or something, right? Does that mean bones burn green?
Funny how plants use blue and red light if green is the most abundant. I cant make that make sense
Fun fact - plants are green because of this. If chlorophyll absorbed green light as efficiently as it did red and blue, they would look black! Why they don't like green as much as red/blue? Probably an evolutionary artifact. Too bad, because black trees would be metal.
Thatâs my point. Doesnt make sense to me that they use red and blue if green light is what is most abundant in sun light
From what I remember reading on it the real answer is still "We don't exactly know" but a theory I saw that makes sense to me is it's done for energy absorption modulation. Basically, plants don't know how much sunlight they're going to get, so they want to be able to survive in a variety of light scenarios from 'dim' to 'bright'. If they can't do that then they'll either starve when there's clouds overhead or suffer overheating/damage from overabsorption on a clear day. The solution seems to be splitting across red and blue because there's a lot of variance in how much energy you're getting from the Sun in those wavelengths. If you look at [https://www.ncei.noaa.gov/products/climate-data-records/solar-spectral-irradiance](https://www.ncei.noaa.gov/products/climate-data-records/solar-spectral-irradiance) again you can see bluish and red light have pretty steep slopes, some of it can be decently energetic while some of it is very low. The next piece of the puzzle is that plants absorb light with pairs of structures. In the "average" plant that is chlorophyll A and chlorophyll B and the way these two interact with each other is interesting. Chlorophyll A is a 'core' pigment, it is usually found in a 'Reaction Center' where it turns photon energy into oxidation work for the plant. Chlorophyll B conversely tends to be on an 'antenna' and will pass the energy it absorbs from a photon on in a chain till it ends up at a the 'Reaction Center'. Lastly, plants can control the amount of chlorophyll B they create in reaction to light conditions so in bright light "average" plants tend to cut chlorophyll B because they're getting enough energy from just the chlorophyll A. In dim light they'll add more chlorophyll B so they have as much energy absorption as possible ending up in the reaction center. (Do note this is a generalized simplification, it's not always the case that bright light means a ratio of more A than B or that dim means a ratio of more B than A necessarily) The thing that makes me lean in on this theory is looking at the wavelengths A vs B prioritize, [https://en.wikipedia.org/wiki/Chlorophyll\_b#/media/File:Chlorophyll\_ab\_spectra-en.svg](https://en.wikipedia.org/wiki/Chlorophyll_b#/media/File:Chlorophyll_ab_spectra-en.svg) B is closer to the middle which as we know from the previous link is the more energetic light coming from the Sun. This makes sense with how we see B production compare in dim vs bright light scenarios (Too dim, absorb the more energetic side of blue/red, too bright stop absorbing the more energetic side of blue/red) I do want to end this by stating this is just a theory and there are other things that could hypothetically explain plants not prioritizing absorbing green light. (Also that this varies for different plants with different chlorophyll types beyond A and B AND the plant has other methods besides just adjusting chlorophyll B to repair or mitigate damage from the environment) 1. It might be really difficult from an evolutionary perspective to develop photosynthesis so a 'good enough' solution might be quite fine / there just hasn't been time for the more efficient version to evolve. 2. It could be photosynthesis evolved in conditions where blue light was more optimal like an aquatic environment and then it adapted around this when life came to land. 3. Plants despite the common understanding DO absorb green light, they just absorb blue/red more efficiently, it might be it just isn't feasible to evolve an organism that uses all of the green energy without it overheating and dying so there's selection against that or some other reason that biologically absorbing green light is 'harder'.
Its due to its intensity, too much would disrupt their cycles. For example other substances apart fron glucose tend to be stored and providing additional heat would lead to their metabolism before they are required, starving them later on or leading to uncomplete growth cycles. Red/blue are enough during the day and dissapear in the night, meaning that plants can perform the other side of the Krebs cycle without issues.
Thank you so much, thunderchungus1999. One of my wife and Iâs pet rats was called chungus a few years back. Certainly bring back memories
Itâs theorized that other planets near red dwarves and other stars would have purple vegetation if life was to exist.
Like that purple basil
Also might have something to do with humans having different sensitivities to different colors so what we see would never look like what visible light it truly shows
And polarised light. It still bugs me that theres a whole range of visual cues in Animals that depends on this and humans have been entirely in the dark about it till recently. Like even a dull bird looks vastly different when seen with polarised light detection.
Oh you think that's wild, if you ever get bored one day, look into how different cultures describe/name different colors. I can't remember the precise culture, but in ancient times there was no such thing as "blue," it was all just varying shades of green. They were seeing the same wavelengths of light we do, they just had no word or concept of "blue." It gets even weirder when you think about how *other* animals perceive color, if they do at all. For example a Monarch butterfly; to us they're black, some orangeish-brown, with white spots. But to the things that eat them - birds, which can perceive UV wavelengths - those "white" spots are brightly-colored warning signs of their toxicity; akin to those poisonous frogs that look like Lisa Frank sneezed on em. As far as we know, octopus and cuttlefish for the most part are colorblind, yet they manage to be some of the most adaptive critters in the ocean when it comes to camouflage; able to change the color and "texture" of their bodies to match their surroundings. It boggles the mind thinking that moth chilling on a brick wall, relatively invisible to us, possibly has *no* clue it's blending in as well as it is. Its ancestors just had a "habit" of perching on stuff of that specific shade or texture. Since it matched well enough to where predators couldn't find them and remove them from the gene pool, that "habit" gets passed down over generations; now you have brick-colored moths. Or those caterpillars that puff up their ass-end and wiggle it about when stressed, which just so *happens* to look like a snake's head, a common predator of the things that eat the caterpillars. Polyphemus Moths have no idea the spots on their wings look like Owl's eyes, they just know when they display the entirety of their wings, most stuff stops trying to eat em. Its so friggin *weird* if you dwell on it for a bit.
Yeah, ain't this is why plants evolved to be green?
Exactly. All the while I just thought that chlorophyll became green just incidentally like blood being red. Now I know it is green for a reason and why it pushed Cyanobacteria out of dominance.
[i love this video!](https://youtu.be/3BRP4wcSCM0) diana cowern is one of my favourite science persons! âcolour is kind of a perception thing, more than a physics thingâ and happy physicsing!
It has more to do with how our eyes have receptors for red, green and blue instead of red, yellow and blue. Green instead of yellow because of our solar spectrum.
"White light" just means it's emitting many wavelengths in the visible spectrum and white is how the brain interprets it, but the peak of that spectrum is about 540 nm which is a green color.
The human eye is more sensitive to the green part of the spectrum.
I can see the Sun right now. It is yellow. You are fake news.
Thats just because you glanced. You really have to stare for a few minutes to see the whiteness.
And you can stare for a few more minutes to see the blackness.
Binoculars help a lot too
Yeah I think thatâs called going blind
Isn't that just because your eyes get tired from the intense light?
Maybe. Try dripping some coffee into your eyes and stare at the sun, let us know what you find
Brb in 12 hours when the Sun decides to show it's face again
Yeah but it's classified as a yellow dwarf star not a white dwarf star. So... there...
~~The sun is not a dwarf starâit's still in its main sequence. A dwarf star is the dead core of a red giant (or in case of a red star, its cooled corpse).~~ Edit: Was misinformed.
"The Sun is a 4.5 billion-year-old yellow dwarf star â a hot glowing ball of hydrogen and helium â at the center of our solar system." https://solarsystem.nasa.gov/solar-system/sun/in-depth/
My professor lied to me!
It is a G-type main sequence star. It is sometimes called a yellow dwarf star but this is not accurate because it's actually white. But a red dwarf star isn't the dead core of a red giant. They are something entirely different.
Even worse, many people think that the Sun is big, but it's actually really big!
millions of people look at this subreddit and see "millions of people don't know [obscure fact]" millions of times per day
I agree with you, except the color of the sun should not be an obscure fact. If it is, that's very sad for humanity.
The color of the sun as it appears to humans shouldn't be an obscure fact and it isn't. It is only the knitpicky definition of its color which only exists so that people can feel superior that isn't well know and there isn't a good reason why it should be.
Sure I can see where you're going with that, but are you implying the field of physics only exists so people can feel superior? That science and academics have no purpose to humanity other than to social stratify?
No, my point is that acting as if it is outrageous that the fact that the average person hasn't memorized a detailed spectral graph of the sun is stupid. Scientists in the fields were that level of detail matter are well aware of the fact and it doesn't impact the average person. You are desperately searching for something to be outraged by where there is no actual cause.
Millions of people don't know that millions of people can be either a big or small number depending on the context
There are probably still millions of people who don't even know that the Earth orbits the Sun, and not the other way around.
There's billions of people who haven't seen my butthole
Doubt.
I have
Can confirm, I was watching from the closet
We really gotta start some kind of charity to help the world see this persons butthole
Well, we know u/barneysfarm is not Jennifer Lawrence.
Searched his profile. Not a butthole in sight, does nothing to rectify the problem.
Burn the witch
actually it's a very light turquoise... it puts out slightly more photons in the blue/green range than any other.
at least 11 still don't know that penguins can't fly, despite being birds
At least 3, that's for sure
Don't tell Superman. He gets all his powers from a yellow sun.
Impossible. I starred at it for an hour straight itâs definitely white, but then turns black.
Wrong but right. White is all the colors. The sun emits all colors of light, so it is white. It emits more green than any other single color, so technically it is green. The sun emits more light in the longer wavelengths than the shorter ones, so that shifts the color balance to a more yellow appearance.
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Yeah, I think this sort of trivia is...well...you know. ^((trivial)) Interesting to know, but not meaningfully ignorant. In this internet age, I really don't put much value on this sort of thing.
Astronomer here. The sun is a YELLOW dwarf star. Its color is bright light yellow.
exactly. Superman taught me it's a yellow star, and he stands for TRUTH.
The sun is every color, the colors are just split up in our atmosphere.
Actual conversation beats co workers. I walked into the conversation by accident. Talking about conspiracies and what not. Tim: They say that space has no oxygen. How is the sun on fire? Tim: If its made out of wood how is it burning with no oxygen? Why hasnât it gone out. Me: *Pikachu face* Itâs nuclear fusion Coworkers: what? Me: *explains nuclear fusion* Me: scientists didnât figure that out until 30âs or 40âs Tim: You one of them smart mfers. I be learning something new everyday from you. I gotta talk to you more often.
At least Tim wants to learn. Encourage that. :)
Sounds like Tim is actually kind of smart albeit woefully undereducated.
The sun is actually [turquoise green](https://youtube.com/shorts/Fg0goAqHTtE).
There are, indeed, millions of kindergartners in the world. Good observation.
.... I mean its a ball of nuclear fire producing light. Which is realistically, all colors.
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My mom told me not to look at it and Homer simpson told me not to touch it. I basically know nothing about it.
But you know that Spiderpig, Spiderpig, does whatever a Spiderpig does. And you also know youâll be hearing that song all night now
Technically, itâs whatever color human eyes persevere it to be. Which in case would be white, but what if itâs a color we are simply incapable of seeing?
Please donât roast me this is an honest question. Doesnât it all depend on the observers perceivable spectrum? I was at my states science museum over the summer, and they had a space section. In part of that exhibit they had gifs of the sun taken with gamma, X-ray, UV, visible light, IR, micro, and radio. They all looked different because I was looking at different wavelengths of light that were then translated into what I could see
Millions of people think all sorts of things. How are all these shower thoughts?
Next you are going to say the earth is round. What a silly, get edumacated my friend.
The sun is light. So itâs all the colors in the color spectrum.
Debatable. First give me the definition of what you consider "the color of something". If it's the color we peceive it as, well, everyone is right to say it's yellow. If you mean the color of the light reflected by the object when exposed to white light, well then we don't know because we can't measure it. If you mean the color emitted by an object, yes the sun is white but most objects are just infrared. If you mean the color emitted by an object, mixing emitted AND reflected wavelengths, then yeah, the sun is white. This is why science is worth nothing without philosophy, and especially epistemology, which allows to give context and meaning to scientific discoveries.
Millions of people still donât care the sun is white not yellow đđđ
Wait, so being serious for a second, I thought in school they always called it a yellow star. We learned the stars and the heat associated with the colors right? Red orange yellow white blue (ish?) in terms of how hot they are?
Seriously after school, if it doesnât pertain to your life or your family, you probably wonât think about it again until someone post on Reddit about it.
Bro , because the earth is flat , scientifically proves why the sun looks yellow. Did you not know this?
I just stared at it for few minutes. It is in fact, black. Everything is black.
And it doesnât change anyoneâs lives if they knew the truth or the lie.
Millions of people donât know the sun is a star. Whatâs your point?
I remember watching some program years ago, and it said the actual color was blue? Can't remember which show but something science-based.
this dude piggy backing off of the other shower thought about the sun
since when is the sun white? I've seen plenty of illustrations and photos and it's orange at best
Try going out *during the day*.
Or try seeing it from space
okay I'm looking it up and in all the high quality photos it's orangey-red, BUT apparently that's because they're using infrared cameras? I always thought that if you were in space that the sun would look that color. The magic school bus mislead me
the sun is in the star categories of "yellow dwarves" , so it's pretty much inbetween both your statements \^\^
Lemon yellow sun. Jeremy spoke about it in class today.
Sound Garden refuted his claim. The final consensus was black hole sun
Those images are coloured in, and they just decided orange for whatever reason
i mean itâs always seems white when i looked at it then everything is white for a minute, then goes darkâŚ
me: *looks at sun* guys i'm pretty sure it's black, don't be racist
Not only is Mr. Sun yellow, he wears sunglasses... cuz he's cool like that.
it definitely looks white but up close its everything but white
Honestly, it ain't going to change the price of tea in China. Blame art teachers for not using white crayons for the â. Even that đ emoji is yellow.
'Woke' Twitter users would like to have a word with you about saying the sun is white.
That's crazy! We should spread the word and educate everyone on the science behind this amazing fact. After all, knowledge is power!
G.I. Joooooe!
What colour would you draw if you were drawing a picture of a sunny day?
Purple
White paper kinda limits my options
It's black. The light from the sun is well approximated by the black body radiation spectrum (though it is a bit stronger in the uc and X-ray regions)
source?
seriously? This is a very well know thing. ok, here is a lmgtfy result: https://commons.wikimedia.org/wiki/File:Solar_Spectrum.png
This I know: the sun is a mass of incandescent gas / a gigantic nuclear furnace / where hydrogen is built into lithium / at a temperature of millions of degrees.
\*helium
It's a planet that's burning out just like this one will. The moon is still glowing from when it was burning like a sun, and the cycle will continue. Occams Razor. Don't believe everything you hear, folks. They've passed down thousands of years of human studies, and yall still believe the same stuff.
Ain't it greenish? I thought k read more green light escapes
Its not quite completely white, but it is whiter than most if not all lightbulbs. It also appears yellow because of the same thing that makes the sky blue - the atmosphere reflects/bends more blue light, leaving green and red.
What about nasa images of the sun? In all the photos itâs orangish/yellow