Vortex winds trigger unprecedented auroras on Saturn

Astronomers have observed for the first time that auroras are driven by winds swirling across Saturn's atmosphere.

Auroras are usually produced by the interaction of energetic particles flowing from the planet's magnetosphere into its atmosphere. On Earth, these particles originate from the Sun, while on Jupiter and Saturn they come from volcanic eruptions on the planets' moons.

However, in a new study published in the journal Geophysical Research Letters, astronomers led by Nahid Chowdhury from Britain's University of Leicester say they have detected a new type of aurora on Saturn caused by winds. swirling in the planet's very atmosphere, which has never been observed before.

Infrared image shows aurora at Saturn's south pole.

The new discovery is not by chance but is based on "some early theories about the aurora". The team used the Keck Observatory's Near Infrared Spectrometer (NIRSPEC) on Mauna Kea Island in Hawaii to observe the swirling winds around Saturn's atmosphere and measure infrared emission. from this area, which is then used to map the planet's weather patterns.

Research shows that Saturn's weather system is driven by energy from the atmosphere, with winds in the ionosphere (located below the magnetosphere), creating the planet's auroras. Vortex winds also appear to be responsible for Saturn's variable rotational speed, making it difficult for researchers to determine how long days last on the ringed planet.

Various spacecraft - including NASA's Voyager and Cassini probes - have attempted to measure Saturn's rotation by tracking pulses of radio emission from the atmosphere, which can be used to determine the day length of the planet. However, the speed of these pulses has varied over the decades between observations by different spacecraft.

"Understanding the planet's physics tells us that Saturn's true rotational speed cannot cause rapid change, so there must be something unique and strange going on. Several theories. been launched since NASA's Cassini mission attempted to explain the mechanism behind these observed cycles.The new study represents the first detection of an underlying engine located in the upper atmosphere of Saturn, which continues to produce both the aurora and the observed cycles of the planet," Chowdhury said in a statement.

The study's lead author added that the results will prompt astronomers to rethink theories about local atmospheric weather patterns and their possible connection to the aurora, not just on the aurora. planets of the Solar System but also on worlds orbiting other stars in our galaxy.