Gliese 581c/d and their Red Sun?

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Discussion Overview

The discussion revolves around the environmental characteristics of Gliese 581c and Gliese 581d, particularly focusing on the appearance of the sky, light conditions, and potential plant life in these extraterrestrial environments. Participants explore theoretical implications for a graphic novel project, considering atmospheric colors, plant adaptations, and the effects of different stellar characteristics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that the sky on Gliese 581c/d could appear redder due to the characteristics of the star, while others propose that life forms on these planets might perceive the sky differently based on their own evolutionary adaptations.
  • Another participant raises the possibility that plant life could evolve to have different colors, such as dark purple or charcoal black, to optimize light absorption under a redder sun.
  • Concerns are expressed about the implications of increased gravity on the morphology of potential life forms, suggesting that it might favor shorter, stockier organisms.
  • One participant argues that the sky would still be blue due to Rayleigh scattering, challenging the idea of a red sky and providing a reference to the temperature of Gliese 581's star, which they claim is around 3,500 K.
  • There is a discussion about the perceived color of the star, with one participant suggesting it would appear light orange rather than red, and speculating on the size and brightness of the star as seen from the planets.
  • Another participant mentions the potential for a thick atmosphere that could influence the sky's color, suggesting it might still appear blue if not too cloudy.

Areas of Agreement / Disagreement

Participants express differing views on the color of the sky and the characteristics of plant life on Gliese 581c/d. There is no consensus on whether the sky would be red or blue, and the discussion remains unresolved regarding the implications of gravity on life forms.

Contextual Notes

Participants reference various assumptions about atmospheric conditions, light absorption, and evolutionary adaptations, but these remain speculative without definitive conclusions.

Butch007
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I am doing some research for a graphic novel I am building with a group that will take place on Gliese 581c/Gliese 581d and am trying to get as accurate information as possible about what the sky, light and plant life would look like in either of these environments. Could this be an accurate representation?
"[URL
Red and Purple Atmosphere?[/URL]
 
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That looks like Earth through a purple filter!
The sky would look redder to us - of course if something eveolved on the planet then the sky would look normal, just as creatures from a bluer sun would think our sky was too red!
Plants
would probably need larger leaves to capture enough energy from the weaker red photons and different photo chemistry of course.
Being much nearer to a larger cooler sun would have different weather patterns and seasons.
 
Thanks MGB. Implying that the photo chemistry would be different begins to hint at the idea that plant life may be completely different from green? Maybe even dark purple or charcoal black to absorb light more effectively? A studio member of mine suggested that the greater gravity of the Gliese "Super Earth" might only support short stocky life which seems to make some logical sense, but also puts a damper on some of my creative concept development (I think the "Super Earth" gravity is estimated as 1.5x greater than earth)
 
The sky would still be blue, I believe, since we get our blue sky from Rayleigh scattering of sunlight.

Also, the star in the image that was linked to is far too red; it would actually be a light orange-ish color. You can see at:

http://www.vendian.org/mncharity/dir3/blackbody/

Gliese 581 is about 3,500 K.
 
FTL_Diesel said:
The sky would still be blue, I believe, since we get our blue sky from Rayleigh scattering of sunlight.

Also, the star in the image that was linked to is far too red; it would actually be a light orange-ish color. You can see at:

http://www.vendian.org/mncharity/dir3/blackbody/

Gliese 581 is about 3,500 K.

That's a nice chart! I can use it to tell the temperature of the electric heating coils on the stove.

So maybe the Gliese sun would look like an apricot? It would look BIG I guess, being relatively close (even tho smaller in absolute size)

Actually isn't the tungsten filament of a 100 watt lightbulb something like 3500 K?
The cast of light might not look all that unfamiliar.
The atmosphere might be very deep and optically thick. If it wasn't too cloudy I expect you are right that it would be blue.
 
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