Neptune is one of the solar system's gas giants, meaning that it is composed entirely of gas. Its upper atmosphere, or surface is composed of three gases. Even though humans will never be able to physically set foot on the planet, satellite visits have revealed a lot about its composition and weather patterns. Understanding the intricacies of planets like Neptune is important for learning about the nature of the universe.
Neptune's surface is composed of 80 percent hydrogen. This is not surprising, since hydrogen is the most common element in the universe, frequently found in gas planets. It is colorless, highly flammable and the lightest element in existence. On earth, hydrogen is used for many things, such as powering vehicles, rocket fuel and even powerful weapons like the hydrogen bomb.
Helium is the second most common element on Neptune, accounting for 19 percent of its surface composition. It also happens to be the second most common element in the universe. Like hydrogen, it is colorless and odorless. On Earth, helium is often associated with floating balloons, since it is still lighter than air. Unlike hydrogen, helium is not flammable, which makes it safer to use.
The final 1 percent of Neptune's atmosphere is made of methane with a few trace amounts of water and ammonia. Out of all three substances, methane has the biggest impact, giving Neptune its blue color. Although methane is colorless, it manipulates the light spectrum so that red light is absorbed and blue light gets reflected. On Earth, methane is harnessed as a natural gas to generate electricity. The biggest threat from methane is its toxicity. When inhaled, it causes an individual to become lethargic and confused, ultimately resulting in death. As a countermeasure, scientists add a rotten egg smell to the the gas in order to alert people of a leak.
In addition to the various gases, the surface of Neptune is composed of massive winds and storms. Neptune's winds are the fastest in the solar system, reaching speeds of 1,500 miles per hour. Additionally, Neptune has a Great Dark Spot, which is a massive storm that can remain for years.