Jupiter’s atmosphere

Astronomers using the NASA/ESA/CSA James Webb Space Telescope have discovered a high-speed jet stream traveling over Jupiter’s equator above the main cloud decks. The jet is traveling 515 kilometers per hour. It is located around 40 kilometers in altitude, in Jupiter’s lower stratosphere, just above the tropospheric hazes next to the boundary between the layers.

Jupiter has a layered atmosphere, and this illustration displays how Webb is uniquely capable of collecting information from higher layers of the altitude than before. Scientists were able to use Webb to identify wind speeds at different layers of Jupiter’s atmosphere in order to isolate the high-speed jet. The observations of Jupiter were taken 10 hours apart, or one Jupiter day, in three different filters, noted here, each uniquely able to detect changes in small features at different altitudes of Jupiter’s atmosphere.

The discovery of this jet is giving insights into how the layers of Jupiter’s famously turbulent atmosphere interact with each other, and how Webb is uniquely capable of tracking those features. Researchers are looking forward to additional observations of Jupiter with Webb to determine if the jet’s speed and altitude change over time.

These results were recently published in Nature Astronomy.

These findings may help inform ESA’s Jupiter Icy Moons Explorer, Juice, which was launched on 14 April 2023. Juice will make detailed observations of the giant gas planet and its three large ocean-bearing moons — Ganymede, Callisto and Europa — with a suite of remote sensing, geophysical and in situ instruments. The mission will characterise these moons as both planetary objects and possible habitats, explore Jupiter’s complex environment in depth, and study the wider Jupiter system as an archetype for gas giants across the Universe.

[Image description: Graphic titled “James Webb Space Telescope Winds on Jupiter.” There is a graph with the y-axis on the left and right label pressure (mbar) and altitude (kilometres).]