Extraterrestrial sky color based on atmospheric composition and sun color

In summary, it seems that one could simulate the color of another planet's sky by changing its atmosphere composition and parent star color.
  • #1

FtlIsAwesome

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How can one determine the color of another planet's sky from its atmosphere composition and parent star color? Earth's atmosphere is blue for most of the day, then turns red at sunset. Mars is sort of the opposite: it has a red sky which turns to a bluish hue at sunset.

[STRIKE]Until someone tells me otherwise, I assume that a human breathable atmosphere would have be a blue hue and not a different color such as green.[/STRIKE] I would certainly think its cool if other colored atmospheres can actually be breathed by humans.
 
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  • #2
FtlIsAwesome said:
Until someone tells me otherwise, I assume that a human breathable atmosphere would have be a blue hue and not a different color such as green.
Scratch that, it seems the atmosphere can have an inert gas other than nitrogen, which I assume will change its color.
https://www.physicsforums.com/showthread.php?t=470447
 
  • #3
Methane can cause a blue colored atmosphere. Mars' atmosphere tends to be redish because it is laden with rust (mineral limonite and magnetite). Magnetite reflects the limomite's reddish hue. The wind picks them up from the ground as dust and spreads them. The blue color seen in the first Mars photos was not the true color. The true color for most of the daytime was found to be butterscotch.

http://www.webexhibits.org/causesofcolor/14C.html
 
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  • #4
Ignoring the effect of colored dust, a plain gaseous atmosphere will tend to scatter blue more than red----will tend to scatter short wavelength more than long.

Light coming to you direct from the sun will tend to be reddened, by how much depending on how much atmosphere it has had to pass thru

Scattering removes blue preferentially and sends it off in random directions

So light rays from the sun that pass overhead, aimed at somebody above and behind us, get their blue removed and scattered randomly and some of it comes down to us and we see the sky as blue (because of that scattered light).

It would work with pretty much any gas molecule, I think. Anyway with a breathable atmosphere it should tend to be

"blue skies, smiling at me:
nothing but blue skies, do I see!"

---Ancient Broadway Tune
 
  • #5
In computer graphics, a bit new trend is to physically simulate the sky, rather than using 'sky boxes' like what was previously done to get realistic skies. There are many prominent people in this field who have released papers, such as Nigarbagea, etc.

Anyway, the point is that you could use these simulators and change the scattering coefficients, etc. to simulate different atmospheres. The scattering equations I would assume do not change from atmosphere to atmosphere (Rayleigh and Mie?) so you could easily find a simulator (or write one) and try changing the atmosphere coefficients and see what happens :)
 

1. What factors determine the color of the sky on an extraterrestrial planet?

The color of the sky on an extraterrestrial planet is determined by the atmospheric composition and the color of the star (or sun) that the planet orbits. These factors interact to produce a specific color of the sky.

2. How does the atmospheric composition affect the color of the sky on an extraterrestrial planet?

The atmospheric composition plays a key role in determining the color of the sky on an extraterrestrial planet. Different gases in the atmosphere absorb and scatter light differently, resulting in different colors. For example, a planet with a predominantly nitrogen atmosphere will have a blue sky, while a planet with a thick carbon dioxide atmosphere will have a yellowish sky.

3. Can the color of the sun also affect the color of the sky on an extraterrestrial planet?

Yes, the color of the sun can also influence the color of the sky on an extraterrestrial planet. Stars emit different colors of light based on their temperature and composition. A hotter star will emit more blue light, resulting in a bluish sky, while a cooler star will emit more red light, resulting in a reddish sky.

4. Are there any other factors that can impact the color of the sky on an extraterrestrial planet?

In addition to atmospheric composition and sun color, other factors such as the planet's distance from its star, the presence of clouds, and the angle of sunlight can also affect the color of the sky. These factors can cause variations in the intensity and distribution of light, resulting in different hues and shades of the sky color.

5. Is it possible for an extraterrestrial planet to have a sky color that is drastically different from Earth's sky color?

Yes, it is possible for an extraterrestrial planet to have a sky color that is drastically different from Earth's. This could be due to a combination of different atmospheric compositions, sun colors, and other factors. For example, a planet with a sulfur-rich atmosphere and a red dwarf star could have a sky that appears more orange or even green in color.

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