Enjoying EarthSky? Subscribe.

270,138 subscribers and counting ...

Jupiter’s independently pulsating auroras

The auroras over Earth’s north and south poles typically mirror each other. But X-ray observations show that Jupiter’s auroras pulsate on different timescales.

Jupiter’s auroras as seen in X-rays, via NASA.

Jupiter is our solar system’s largest planet, and its auroras are by far the strongest in our sun’s family. In a way similar to earthly auroras, Jupiter’s northern and southern lights stem from activity on the sun. A couple of months ago, a study using data from the Juno spacecraft, which is currently orbiting the planet, said that Jupiter’s auroras may be accelerated by waves in the giant planet’s magnetic field (a process researchers described as “akin to surfers being driven shoreward ahead of breaking ocean waves”). On November 6, 2017, NASA described another recent study in which X-rays astronomers tracked the behavior of Jupiter’s northern and southern lights, which seem to pulsate, or change in X-rays brightness, independently. NASA said:

The X-ray emission at Jupiter’s south pole consistently pulsed every 11 minutes, but the X-rays seen from the north pole were erratic, increasing and decreasing in brightness — seemingly independent of the emission from the south pole.

That’s surprising because Earth’s auroras generally mirror each other. William Dunn of the University College London led the research, which was published October 30 in the peer-reviewed journal Nature Astronomy.

According to a statement from the research team, the study relied on data using the Chandra X-ray and XMM-Newton observatories:

… from March 2007 and May and June 2016, a team of researchers produced maps of Jupiter’s X-ray emissions and identified an X-ray hot spot at each pole. Each hot spot can cover an area equal to about half the surface of the Earth.

The team found that the hot spots had very different characteristics.

This makes Jupiter particularly puzzling. X-ray auroras have never been detected from our solar system’s other gas giants, including Saturn.

The X-ray team plans to combine new and incoming data from Chandra and XMM-Newton with data from the Juno mission, which is currently in orbit around the planet. If scientists can connect the X-ray activity with physical changes observed simultaneously with Juno, they think they might be able to determine the process that generates the Jovian auroras and by association X-ray auroras at other planets.

Read more from NASA

Bottom line: The auroras over Earth’s north and south poles typically mirror each other. But X-ray observations show that Jupiter’s auroras pulsate on different timescales.

Deborah Byrd

MORE ARTICLES