NASA has spacecraft orbiting planets and collecting data to help scientists learn more about our solar system. One of the spacecraft that is currently operating is called Juno and is in orbit around Jupiter. Juno detected new auroral emissions on Jupiter that appear to ripple over the planet’s poles.
Dawn was discovered using the ultraviolet spectrograph (UVS) on board the Juno. NASA says that auroras are characterized by very weak ring-shaped emissions that expand rapidly over time at speeds between two and 4.8 miles per second. Scientists believe that the dawn is triggered by charged particles from the edge of the giant planet’s magnetosphere.
Scientists believe that the weak ultraviolet features originate millions of kilometers from Jupiter, near the border of the Jupiterian magnetosphere with the solar wind. The solar wind is a supersonic stream of charged particles emitted by the sun, and when the particles reach Jupiter, they interact with its magnetosphere. Scientists today don’t quite understand the interaction between the solar wind and Jupiter’s magnetosphere.
The auroras on Jupiter bond to charged particles within the magnetosphere, just as on Earth. A significant difference is that Jupiter has a much more powerful magnetosphere, about 20,000 times stronger than Earth’s. The incredible strength of Jupiter’s magnetosphere allows it to deflect the solar wind from up to 4 million miles away from the planet.
Scientists say the location of the high latitude auroral rings indicates that the particles causing the emissions come from the planet’s magnetosphere. Charged particles recorded by the UVS instrument appear to come from the ends of the magnetosphere, where the plasma from the solar wind interacts with the plasma of Jupiter. The researchers believe that the interaction can create ring-like features, known as Kelvin-Helmholtz instabilities, capable of traveling along the lines of Jupiter’s magnetic field. Another possibility of causing the auroral characteristics could be magnetic reconnection events on the day side of the planet.