Uranus appears blue primarily because of methane in its atmosphere.
Here's a more detailed explanation:
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Atmospheric Composition: Uranus's atmosphere is primarily composed of hydrogen and helium, similar to Jupiter and Saturn. However, it also contains a small amount of methane, along with traces of water and ammonia.
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Methane's Role: Methane gas absorbs red light and other longer wavelengths of light. When sunlight hits Uranus, the methane in the atmosphere absorbs the red portion of the light spectrum.
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Scattering of Blue Light: The remaining blue-green light is then scattered back into space. This scattering process, combined with the absorption of red light, gives Uranus its characteristic blue-green hue.
In simpler terms, Uranus is blue because methane in its atmosphere absorbs red light and reflects blue light back to our eyes.
