Is it yellow because from Earth it usually looks yellow to us? Or is it white because the sun gives off all wavelengths of light (white light)? Or is it some other color?
In: Planetary Science
Stars are “black body” radiators. They glow because they’re hot, and they emit photons at a broad spectrum of energies (a spread of colors). Because of this broad spectrum, they’re all more or less “white”: the light is a blend of all the colors
The hotter the star’s surface, the more energetic photons they emit. More energetic photons are higher frequency, or “more blue”. But it’s never a pure blue: it won’t make a red object look black.
Instead, there are different colors of “white light”, and we refer to them by “color temperature”, which is literally the temperature (in Kelvin) of the black body source that emits that spectrum. The sun is around 5700K. An indoor lightbulb is around 2700K, so it looks more yellow-orange than daylight.
The great thing about this question is it really does belong on ELI5 because… **you decided or were told the sun was yellow when you were about 5 years old.** Remember? You had a white piece of paper and a box of crayons. You wanted to draw a picture of a horse in a field on a sunny day.
horse? brown crayon
grass? green crayon
sky? blue, duh.
sun? sun? sun? uhhh.. you didn’t want to just leave an empty white circle on the page. You wanted to DRAW the sun. So what color? Can’t be red — you already knew what the world looks like under red sunlight near sunset. Blue? No, you can see that the sun is different from the sky, and the sky is blue, so the sun must not be. Green just doesn’t seem right either.
Anyway, you already saw your older brother’s drawing. He used yellow. So that’s probably right.
The sun is white because our eyes perceive light from the sun that way. There is no objective definition of “white” other than what appears as white to us. Aliens who evolved on a planet with a different sun would likely see it as “not white” or tinted either as a color of a shorter wavelength or a longer one.
Consider bulbs labeled “daylight”, “bright white” or “warm white”. These bulbs have light distributions representing the light output from different plasma temperatures. The “warm white” is reddish.
Anecdotally, I had a cool moment where I was looking outside through a tinted window while wearing polarised sunglasses. The sun was behind I guess some thin clouds because I could look at it without it hurting my eyes (I know it could still probably damage them I only looked for like literally 2 seconds). Though all that it looked like a perfectly (I mean perfectly) round white circle, with no way to tell it was a sphere. It just looked like a perfectly white 2D disk in the sky, super weird.
It’s all of them. The sun emits all colours of light in teh visible spectrum, as well as lots of light we can’t see (infra red, ultra violet and beyond). The atmosphere filters out some of this light, but most of it still gets through.
[This is the solar spectrum, both in space and in the atmoshere.](https://www.researchgate.net/profile/Anna-Dal-Farra/post/What_range_of_the_solar_radiation_spectrum_impacts_the_most_on_the_albedo_of_a_surface_is_400-800_a_good_estimate/attachment/59d622616cda7b8083a1bffe/AS:273843313152001%401442300741958/download/2000px-Solar_spectrum_en.svg.jpg)
It’s white. If you were to look at it mid day (don’t do this) you would see that it is white. It’s only later in the day where is gets low in the sky that it turns yellow because the light had to go through a lot more atmosphere.
Funny enough I saw a conspiracy theory that the sun had changed colors recently (due to chemtrails or vaccines or Jews replacing it one night or something else, I don’t really know). Since cameras are now ubiquitous, it’s easy to take a picture of the sun midday at see that it is white. So people who grew up only getting a good look at it in the evening were surprised that it looks different midday.
How come other stars don’t look more yellow near the horizon like the sun does?
Ok there are quite a few inaccuracies in these answers so I need to clear some things up. First, the sun is white. It’s not green, it is white. Stating the suns colour off a peak in the spectrum ignores the fact that it is still emitting all wavelengths of visible light (actually, all wavelengths of the EM spectrum). The problem with using a peak of a broad distribution to determine colour also ignores that there are different ways to plot a stars brightness. You can plot it as a function of frequency (making it “infra red”) or a function of wavelength (making it “Violet”). Both are perfectly correct ways to plot brightness, so why do we get two different answers? Again, because using the peak in the spectrum doesn’t determine colour.
In addition, the idea that the sun is a perfect blackbody emitter is wrong and over simplified. If you model the sun as a perfect blackbody, and plot it’s brightness as a function of wavelength then it is “green”. Astronomers use this model because it is convenient, but it is a simplification. An actual astronomer will tell you that the sun absolutely is not green but white. However news headlines love to say “the sun is green” without understanding why astronomers model it that way. TLDR the sun is white, it emits all colours in the visible spectrum which makes it white. Using the peak of a broad distribution of wavelength/frequency is not a way to determine colour
So are recent videos taken of the sun surface false-color? There isn’t a one that doesn’t make the sun look orange/molten.
Depends on the eyeball looking at and with what tool. Is the star directly overhead or on the horizon? Any atmospheric pollutants?
Question, did the astronauts on the moon take pictures of the sun or would it be impossible in visible light without an atmosphere? Everything in a search seems to be CGI. Even NASA’s website only yields pictures in different wave lengths.
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