What is Neptune's atmosphere made up of?

Answer 1

Neptune's thick atmosphere consist of 74% hydrogen, 25% helium and about 1% methane.

Answer 2

The atmosphere of Neptune is similar to all the large planets in the Solar System; it mostly consists of hydrogen and helium, with trace amounts of methane, water, ammonia and other ices. But unlike the other gas planets in the Solar System, Neptune's atmosphere has a larger proportion of the ices. It's the methane in the plant's upper atmosphere that gives it its bright blue color.

At the highest altitudes, where the Neptune's atmosphere touches space, it consists of about 80% hydrogen and 19% helium. There's also a trace amount of methane. The light we see from Neptune is actually the reflected light from the Sun. (Although the entire spectrum of light hits Neptune.) This trace amount of methane absorbs light from the red end of the spectrum, while allowing the blue light to bounce back out. The color of Neptune's atmosphere is brighter than Uranus, which has a similar atmosphere; astronomers aren't sure why there's such a dramatic color difference.

Answer 3

Neptune's atmosphere consists of 74% hydrogen, 25% helium and about 1% methane.