Color of sky based on atmosphere density

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
15 replies · 2K views
aiop
Messages
38
Reaction score
0
If the atmosphere was thiner would the sky be violet?, and if it was thicker would it be red?
 
Last edited by a moderator:
Physics news on Phys.org
For a better understanding of the color of our sky google "why does the sky look blue".
 
The answer to your question is simple enough that I'm going to let you think about this: The reason our atmosphere is blue is because the light is refracted from the air and the blue part of light's spectrum is what reaches our eyes. As the sun sets, the light is refracted in a different way causing other colors of the spectrum to reach our eyes.
Venus's atmosphere is denser than our own, and it turned out to be yellow-ish. Based on that information I believe you can now answer your question.
 
"Venus appears to be a yellowish color, which is caused by sulfuric acid in the thick atmosphere of the planet."

While there is an increase in reflectivity with pressure in air; I have found the above reference quote that brings into question the actual effect of the density of Venus' atmosphere upon it its color; but, I have not been able to find any other references that directly speak to the source of the color.
 
JBA said:
"Venus appears to be a yellowish color, which is caused by sulfuric acid in the thick atmosphere of the planet."

While there is an increase in reflectivity with pressure in air; I have found the above reference quote that brings into question the actual effect of the density of Venus' atmosphere upon it its color; but, I have not been able to find any other references that directly speak to the source of the color.
The majority of the yellow comes from the abundance of sulfur and sulfur dioxide. I was just picking Venus because I know it has a denser atmosphere. I didn't fully take the composition of the atmosphere into consideration. I apologize for that.
 
CrackerMcGinger said:
The answer to your question is simple enough that I'm going to let you think about this: The reason our atmosphere is blue is because the light is refracted from the air and the blue part of light's spectrum is what reaches our eyes. As the sun sets, the light is refracted in a different way causing other colors of the spectrum to reach our eyes.
Venus's atmosphere is denser than our own, and it turned out to be yellow-ish. Based on that information I believe you can now answer your question.

This is nonsense. Go to Wikipedia and look up 'Rayleigh scattering'
 
  • Like
Likes   Reactions: davenn
a_potato said:
This is nonsense. Go to Wikipedia and look up 'Rayleigh scattering'
I wouldn't use Wikipedia. It is able to be edited by anyone. If you don't believe me, go on Wikipedia and then click the edit on a page. That's how I know Wikipedia is not a reliable source.
 
CrackerMcGinger said:
I wouldn't use Wikipedia. It is able to be edited by anyone. If you don't believe me, go on Wikipedia and then click the edit on a page. That's how I know Wikipedia is not a reliable source.
Nonetheless refraction is an incorrect explanation and Rayleigh scattering is a correct one.
 
  • Like
Likes   Reactions: davenn
jbriggs444 said:
Nonetheless refraction is an incorrect explanation and Rayleigh scattering is a correct one.
agreed

@CrackerMcGinger you need to go do a bit more reading before posting incorrect info :smile:

Dave
 
I know this is constructive criticism, but can we please get back to the main reason of this thread? I know I answered incorrectly, and I do apologize for that, but we could be helping the starter by telling him/her what to look up (not with Wikipedia) while explaining why I'm wrong, instead of just telling me it's wrong and not giving an explanation why. This would benefit not only me, but the starter as well.
 
CrackerMcGinger said:
I know this is constructive criticism, but can we please get back to the main reason of this thread? I know I answered incorrectly, and I do apologize for that, but we could be helping the starter by telling him/her what to look up (not with Wikipedia) while explaining why I'm wrong, instead of just telling me it's wrong and not giving an explanation why. This would benefit not only me, but the starter as well.
While Wikipedia may not be utterly reliable, it is usually quite good and does provide references. You can Google for Raman scattering and Rayleigh scattering.

Refraction as an explanation does not appear to pass the "sniff test". The refractive index of air is small and the variation of that refractive index with respect to frequency is even smaller. The primary effect of refraction would be to deflect an image through a small arc. Yet when looking at the sun, moon and stars, we do not ordinarily notice any prismatic fringes at the edges of the image. We do notice "twinkling" of stars but, as expected, that is a small deflection. The blue sky involves deflections of up to nearly 180 degrees from the incident light. It is hard to explain that as a refractive effect.
 
jbriggs444 said:
While Wikipedia may not be utterly reliable, it is usually quite good and does provide references. You can Google for Raman scattering and Rayleigh scattering.

Refraction as an explanation does not appear to pass the "sniff test". The refractive index of air is small and the variation of that refractive index with respect to frequency is even smaller. The primary effect of refraction would be to deflect an image through a small arc. Yet when looking at the sun, moon and stars, we do not ordinarily notice any prismatic fringes at the edges of the image. We do notice "twinkling" of stars but, as expected, that is a small deflection. The blue sky involves deflections of up to nearly 180 degrees from the incident light. It is hard to explain that as a refractive effect.
Thank you Briggs for explaining why I'm wrong. I tried to argue with my sister that Wikipedia does provide some reliable info, but she still says not to use it. I listened to her because she's 20 and I'm only 14.
 
CrackerMcGinger said:
Thank you Briggs for explaining why I'm wrong. I tried to argue with my sister that Wikipedia does provide some reliable info, but she still says not to use it. I listened to her because she's 20 and I'm only 14.

I find wikipedia to be an excellent place to go for a general overview of a topic. The places where wikipedia is unreliable tends to be in the details of more advanced topics. But that's okay. It's just an encyclopedia, not a textbook. Don't use wikipedia for school projects, and always check the references if you're unsure about the validity of the page.
 
Drakkith said:
I find wikipedia to be an excellent place to go for a general overview of a topic. The places where wikipedia is unreliable tends to be in the details of more advanced topics. But that's okay. It's just an encyclopedia, not a textbook. Don't use wikipedia for school projects, and always check the references if you're unsure about the validity of the page.
That's why I don't use it. I'm studying FTL(Faster Than Light) and it's a bit difficult to study when you don't have the resources to do so. Everything, and I mean everything, I have to research has to do with advanced physics.
 
nasu said:
Is the color of the sky part of these advanced topics in Physics that you research?
No. But it is for the stuff I research. What Drakkith said is true. I research FTL theories, Special Relativity, properties of quarks, anti- particles, properties of gravity, and properties of light.