Neptune’s Incredibly Fast Winds

September 2, 2021

View of Neptune.

If you would like an impossible challenge, try flying a kite or doing anything else in the winds on the planet Neptune. It’s guaranteed to be pretty ugly because the winds on the planet can reach 1,200 miles per hour (1,931 kph), the fastest winds in the solar system.

Neptune is the third most massive planet in our solar system and has ten times the mass of Earth. The surface of Neptune is composed of an ocean of ammonia and water, making it an icy giant. But why are the winds on Neptune, which are composed of hydrogen, helium, and traces of methane, so strong?

While it is still a mystery how the winds can reach supersonic speeds, scientists are learning how deep the winds go on the planet. They’ve investigated the planet’s gravity field to determine where the winds occur through data obtained from Voyager 2 and ground-based telescopes, all without being able to see to the surface.

They discovered that the windy layers of Neptune are confined to narrow jet stream bands that only occupy the outermost 0.2% of its mass. This means that the winds only occur in the upper atmosphere of the planet, unlike Earth, where winds are driven by processes throughout the atmosphere and at the surface. Scientists figured this out by measuring the gravitational force from the planet as it affected the trajectory of Voyager 2 as it passed by Neptune in 1989.

While this has helped explain where the winds act on Neptune, it is still unknown what energy is driving the strong winds. Some scientists theorize that the extremely cold temperatures could reduce the friction in the atmosphere, thus allowing the winds to blow faster, or that Neptune’s high internal temperature could be causing the extreme winds since the planet gives off more energy than it receives from the sun.

Sources: NASA(1), NASA(2), National Weather Service,, Smithsonian National Air and Space Museum

About the author 

Daniel Ganninger - The writer, editor, and chief lackey of Knowledge Stew, the author of the Knowledge Stew line of trivia books, and editor of Fact World and the Knowledge Stew sister site on Medium, our ad-free subscription sites. I hope you learn many new things here that add to your knowledge.

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