The mystery surrounding the gas giant’s bright northern and southern lights has been solved. Planetary astronomers used data from NASA’s Juno spacecraft orbiting Jupiter, as well as data from ESA’s (European Space Agency) Earth-orbiting XMM-Newton mission, to solve a 40-year-old puzzle concerning Jupiter’s peculiar X-ray auroras.
They’ve seen the full process in action for the first time.
The X-rays are produced by electrically charged atoms, or ions, surfing electromagnetic waves in Jupiter’s magnetic field down into the gas giant’s atmosphere.
The work was published in the journal Science Advances on July 9th.
Auroras have been discovered on seven of our solar system’s planets.
Some of these light shows may be seen with the naked eye, while others produce wavelengths that can only be seen with specialist telescopes.
The production of shorter wavelengths necessitates greater energy.
Jupiter’s auroras are the most powerful in the solar system, and it is the only one of the four big planets with an aurora that emits X-rays. Since its discovery four decades ago, planetary astronomers have been fascinated by Jupiter’s X-ray auroral emission. It was not immediately evident how the energy required to make it is generated.
They knew that ions falling into Jupiter’s atmosphere were responsible for the strange northern and southern lights. However, scientists had no clue how the ions that cause the X-ray light display get into the atmosphere in the first place until now. Auroras are normally only seen on Earth between 65 and 80 degrees latitude, in a band surrounding the magnetic poles.
Because the magnetic field lines depart Earth and connect to the magnetic field in the solar wind, which is the steady flux of electrically charged particles emitted by the Sun, auroral emission fades beyond 80 degrees.
These are known as open field lines, and in the classical model, Jupiter’s and Saturn’s high-latitude polar regions should not produce significant auroras.
Now that the missing piece of the process has been discovered for the first time, a plethora of new avenues for research has opened up. The magnetic field of Jupiter, for example, is packed with sulphur and oxygen ions released by the moon Io’s volcanoes.
Enceladus, Saturn’s moon, shoots water into space, filling Saturn’s magnetic field with water ions.
