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
It would look white if you saw it from space/outside the atmosphere. It appears more yellow to us because the blue/shorter wavelengths get scattered on the way to your eyes through the atmosphere.
The sun in space is a green color. Green is a peak wavelength color and acts like white in the sense we know it on earth – scatters to all color wavelengths.
The sun looks yellow / orange / red on earth depending on a couple factors such as pollution and visibility as well as the angle the sun is coming into view.
The reason it’s orange and browner at sunset is because the angle the light hits the earth scatters all the lighter wavelengths. And when it’s high in the sky is as close to whiteish yellow as we could fathom because the earth is getting as much of the wavelengths the sun can give without being massively scattered thru the ozone.
It’s white. Photos taken of it show white, especially if taken from space so the atmosphere doesn’t mess things up.
You can also view it through a very strong (solar rated*) color-neutral filter and yep… it’s white. I’ve actually done this personally.
We perceive some yellow because blue gets scattered away aggressively by the atmosphere (this is why the sky is blue), and white light minus blue light equals yellow to humans.
The sun is white by definition, because sunlight is what white light is, that’s where the idea comes from. It’s a mixture of the visible spectrum in roughly equal quantities.
It looks yellowish on Earth when the atmosphere starts scattering it.
It does peak in green, though, so if you want to annoy people you can go around with that factoid, saying it’s AKHTUAHLY green.
The sun is white, as pictures taken from space can prove https://upload.wikimedia.org/wikipedia/commons/8/83/The_Sun_in_white_light.jpg It appears yellow because the gases in the atmosphere all absorb and reflect different parts of the visible light, and the part that reaches our eyes after all that is similar to yellow.
But other gases in the atmosphere can change the color it appears to be. Like large fires, even where there’s no obvious smoke in the sky, will make the sun appear red. Even though you can’t see it, the materials put in by the fire are enough to absorb a bit more of the color.
Do other people really see the sun as yellow? It’s generally white unless it’s really late in the day and there’s a lot of atmosphere for it to pass through.
Here is the sun’s spectrum of visible light:
[https://scied.ucar.edu/image/sun-spectrum](https://scied.ucar.edu/image/sun-spectrum)
Since it contains almost all wavelengths with only some tiny black spots (in the spectrum), which are created by absorption, it would look white, and we could not see the slight green tint.
I have an astronomy degree, and teach physics. The Sun is, essentially, white. If you take a look at the percentage of photons radiated from the Sun as a function of wavelength, the highest percentage are those around 500 nm, which is perceived as green to the human eye. However, the Sun also emits plenty (Although fewer) photons in various other wavelengths, in a distribution roughly approximated by that of a blackbody radiator with the same surface temp of the Sun (Google “Sun blackbody spectrum,” it will show you a decent model of it).
Because sunlight not only emits green, but also comparable amounts of surrounding wavelengths of light, these all blend together when registered by the human eye. Our eyes register a relatively spread out distribution of these wavelengths as “White,” and so that’s what the Sun appears to be for us.
Hotter stars shift more towards blue, and cooler stars towards red. The yellow/orange appearance of the Sun during the morning/evening is because that white sunlight is traveling through a thicker column of air before reaching an observer. Blue light scatters more readily than red light in Earth’s atmosphere, so the blue light is “Filtered” during sunrise/sunset, giving them their distinctive hues. The effect that causes this is known as Rayleigh scattering, if you want to learn more.
It’s actually “OH MY GOD MY EYES ARE BURNING I SHOULD NOT HAVE LOOKED AT THE SUN” coloured.
But for a machine, it will look whitish. If it counts photons it may find more green ones than other colours, but in photos it will still look whitish.
Our atmosphere acts as a filter removing a lot of the blue (which gets scattered), so from the ground it looks more yellowish.
Green, technically. That is, it puts out more green light than any other. But it puts out so much light in total that it just appears white to our eyes.
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