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Name: Joseph
Status: other
Grade: other
Location: NC
Country: USA
Date: Summer, 2011

I am a fantasy space artist; however, I am trying to drift back towards realism. My question is are there any major gas compositions that would result in a gas giant being primarily green in nature. I am aware of light green/cyan being present in our own solar system, but I am wondering about the reality of a primarily green hue.

Dear Joseph,

Good question.

Uranus is genuinely greenish, while Neptune is more bluish.


David H. Levy

You have to be very careful when talking about "color" because it is both a physical phenomenon and a physiological phenomenon. Roughly color and wavelengths follow the pattern: ~475 nm = blue; ~510 nm = green; ~570 nm = yellow; ~650 nm = red. The light emission from a stellar source is not a single "color", but a mixture of wavelengths that depend upon the composition and temperature. But also keep in mind that the "color" is a function of the sensitivity of the eye (For example, the eye doesn't "see" infrared or ultraviolet light) and the eye's sensitivity changes from one visible wavelength to another, and this varies from person-to-person. In addition, mixtures of wavelengths give a different visual response. If you want to research your question in all its detail do a search on the terms: "wavelength and color". You will then appreciate how complicated a simple term like "color" really is.

Vince Calder

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