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Does white light have a wavelength, and I know that the sun emits white light, but the atmosphere makes it refract to make it appear yellow to us. Do all the stars in the universe emit white light?

Qmechanic
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Redouane Belfakih
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  • Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. – Community Aug 31 '21 at 19:46
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    Please only ask one question per post - only ask several if they are so closely related that it wouldn't make sense to split them up since they cannot reasonably be answered separately. That way, answerers that might be able to answer one question but not the others still can provide useful, complete answers to a question. For the composition of white light, have a look at https://physics.stackexchange.com/q/228926/50583 and its linked questions. – ACuriousMind Aug 31 '21 at 19:53

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A laser's light is monochromatic, i.e. of one wavelength.

A named colour in the spectrum comprises a range of wavelengths, but the borders are a linguistic convention, not a physical truth.

Any glowing object emits a range of wavelengths extensively, and more extreme ones to a negligible extent. Our eyes have evolved to see most of what the Sun emits, and we call that "white".

Other stars of a very different surface temperature glow in much the same way, but with a rescaled central wavelength range. Our Sun-adapted eyes see such stars' light in a way we describe with suitable colours other than white. Star types often mention such a colour in their name. Cooler stars may look red; hotter ones may look blue.

J.G.
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White light is a mix of various wavelengths. Visible light is approx. 0.4 to 0.7 um.

The apparent color of light is a complicated subject having to do with several factors. The distribution of wavelengths in the light is an important factor. So are the intensity, the condition of your eye, the length of exposure, the context (meaning what is nearby), and I am likely forgetting a few. You can get some indication of these by searching for such things as "optical illusion." Or you could look up some art theory to find why certain color patterns in paintings are pleasing, and others are not.

The sun does have some yellow in its hue. The atmosphere does make a difference.

Not all stars emit white light. There are different colors, among other reasons, because of the temperature of the surface.

puppetsock
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