Which planet is described as an ice giant with an atmosphere of hydrogen, helium and methane?

Which planet is described as an ice giant with an atmosphere of hydrogen, helium and methane?

• A. Neptune
• B. Uranus
• C. Mars
• D. Mercury

Answer: (B)

Ice giants are large planets with thick outer atmospheres dominated by hydrogen and helium, sitting atop icy interiors that include methane, water, and ammonia. The presence of methane in the upper atmosphere is especially notable because it absorbs red light and gives these planets their blue-green tint. Uranus fits this description well. Its atmosphere is mainly hydrogen and helium, with methane present in the upper layers, which contributes to its pale blue color. Mars and Mercury are rocky worlds with only very thin or negligible atmospheres, so they don’t match the idea of an ice giant with methane in the atmosphere. Neptune also shares the same basic composition, but the description points to Uranus in this context.

Ice giants are large planets with thick outer atmospheres dominated by hydrogen and helium, sitting atop icy interiors that include methane, water, and ammonia. The presence of methane in the upper atmosphere is especially notable because it absorbs red light and gives these planets their blue-green tint.

Uranus fits this description well. Its atmosphere is mainly hydrogen and helium, with methane present in the upper layers, which contributes to its pale blue color. Mars and Mercury are rocky worlds with only very thin or negligible atmospheres, so they don’t match the idea of an ice giant with methane in the atmosphere. Neptune also shares the same basic composition, but the description points to Uranus in this context.