Scientists Unravel 40-Year-Old Mystery of Jupiter’s Unusual X-Ray Auroras

Solved: 40-Year Mystery of Jupiter’s Northern Lights

Jupiter’s X-ray auroras had baffled scientists for almost 40 years, but they eventually claimed to have solved the mystery. For the first time, they observed how the entire process worked, and they believed it might have been happening on other planets too. The discovery and its findings were published in July in the journal Science Advances. Finally, there were answers to questions like: What were these auroras? How were they formed? And why did they occur only on Jupiter? Let's delve into the discovery and explore how Jupiter's auroras interacted with other elements in space.

Groundbreaking Discovery

The mystery of Jupiter's auroras had baffled scientists for years. To solve it, they studied the X-ray flares and Jupiter’s magnetosphere using NASA's Juno probe. Meanwhile, the European Space Agency, through its XMM-Newton telescope, had continuously monitored Jupiter's X-rays. The team discovered that these X-ray flares were caused by regular vibrations in Jupiter's magnetic field. These vibrations created plasma waves, pushing heavy ions along the magnetic field lines until they collided with Jupiter’s atmosphere. William Dunn, the study's co-lead author and an astrophysicist at University College London, told Space.com , "It seemed like the processes responsible for Jupiter’s ion aurora and Earth’s ion aurora were the same. This hinted at a potential universal process for space environments."

What Creates an Aurora’s Magical Glow?

Aurora borealis and aurora australis were colorful light displays in the sky seen from high latitudes. Knewz.com noted that on Earth this phenomenon occurred when electrically charged particles from the sun came into contact with oxygen and nitrogen atoms in the atmosphere. Many planets experienced this, but Jupiter's auroras were particularly surprising, as it was the only gas giant with auroras that produced X-rays. Dunn explained Jupiter's aurora formation to EarthSky : "What we saw in the Juno data was this beautiful chain of events. We saw the compression happen, we saw the EMIC wave triggered, we saw the ions, and then we saw a pulse of ions traveling along the field line. A few minutes later, XMM saw a burst of X-rays." Their study also showed that these X-ray auroras on Jupiter pulsed every 27 minutes.

The Advanced Spacecraft Missions

Nasa's Juno probe traveled between 62 and 68 times the distance of Jupiter's radius, which was about 2.8 to 3 million miles. During this time, scientists were alerted, and ESA's telescope began comparing Juno's data for any signs of magnetic activity. Following the discovery, they identified something called electromagnetic ion cyclotron (EMIC) waves, according to NASA . In this region, particles were guided along magnetic field lines. Additionally, Jupiter's X-ray auroras released as much energy as a power station produced in a few days, about a gigawatt.

Aurora Research on Other Planets

Jupiter's aurora project was not complete with this discovery, and ESA's 'Juice' mission was set to reach the planet by 2029 to study its atmosphere and magnetic field. Additionally, it was supposed to explore how its four largest moons affected its auroras. Professor Graziella Branduardi-Raymont of UCL’s Mullard Space Science Laboratory stated, "With the arrival of the satellite Juno into Jupiter’s orbit, astronomers now had a fantastic opportunity to study an environment that produced X-rays up close." Furthermore, Zhonghua Yao, the study's co-lead author and a planetary scientist at the Key Laboratory of Earth and Planetary Physics in Beijing, told EarthSky , "This was a fundamental process that applied to Saturn, Uranus, Neptune, and probably exoplanets as well."