The strange hexagon on Saturn is much bigger than scientists thought

The strange hex swirling around the north pole of Saturn is much larger than scientists thought, suggests a new study.

The researchers generally considered the hexagon 32,000 kilometers wide, a jet composed of air moving at about 320 km / h, as a lower atmosphere phenomenon, limited to clouds of the troposphere of Saturn.

According to a new study, the bizarre structure actually extends about 300 km above these peaks, in the stratosphere, at least in spring and summer. [Stunning Photos: Saturn’s Weird Hexagon Vortex Storms]

The hexagon, which surrounds a smaller circular vortex located at the North Pole, has been in existence for at least 38 years; NASA Voyager 1 and Voyager 2 spacecraft spotted the device at sharp angles when they flew over Saturn in 1980 and 1981, respectively.

Scientists began to look much more closely at France in 2004, when NASA's Cassini spacecraft began orbiting the ringed planet. But observations of Cassini's hexagon were virtually confined to the troposphere for a decade after its arrival; spring did not arrive north of Saturn until 2009, and low temperatures in the stratosphere continued to compromise measurements made by the composite infrared spectrometric instrument (CIRS) probe for another five years .

"We were able to use the CIRS instrument to explore the northern stratosphere for the first time starting in 2014," said Sandrine Guerlet, co-author of the Dynamic Meteorology Laboratory of France, in a statement from the United States. European Space Agency (ESA). .

These observations have now been analyzed. And they revealed a surprise: the presence of a familiar form above the clouds.

"As the polar vortex became more and more visible, we noticed that it had hexagonal edges, and we realized we were seeing the pre-existing hex at much higher altitudes than we previously thought," he added. Guerlet.

The formation of a stratospheric hex appears to be related to the warming caused by the changing seasons, the research team wrote in the new study. Indeed, Cassini spotted a whirlwind over the South Pole during her first years at Saturn, while this hemisphere was enjoying the summer. (Saturn puts 30 terrestrial years in orbit around the sun, so the seasons on the ringed planet last about 7.5 years).

But the southern stratospheric vortex was not hexagonal. And the vortex that revolves around the South Pole, in tropospheric clouds, is also not, according to the researchers.

"This could mean that there is a fundamental asymmetry between the poles of Saturn that we still have to understand, or that the northern polar vortex was still developing in our last sightings and continuing after the disappearance of Cassini." , from the University of Leicester in England, said in the same release.

This disappearance occurred on September 15, 2017, when members of the mission team led Cassini into a fiery death in the atmosphere of Saturn. The long-life orbiter was low in fuel, and the team wanted to make sure that Cassini never contaminated the moons of Saturn, Titan and Enceladus – both capable of supporting life as we know it – with microbes of the Earth.

The asymmetry between the north and the south is only a vortex-related mystery that scientists chew on. Another is the striking form of the Nordic feature: it is unclear why the jet should form in a hexagon. The jet of the Earth did not do such things, for example.

The Cassini mission of $ 3.9 billion – a joint effort by NASA, ESA and the Italian Space Agency – also launched a lander called Huygens on the surface of Titan in January 2005. As indicated the new study, the data collected could the mysteries of the ringed planet, even though Huygens and the Cassini orbiter are no longer with us.

"The Cassini spacecraft continued to provide new knowledge and discoveries until the very end.For a capable spacecraft like Cassini, these mysteries would have remained unexplored," said Nicolas Altobelli, scientist of the Cassini-Huygens project. "It shows all that can be accomplished by an international team that sends a sophisticated robotic explorer to an unexplored destination before – with results that continue to flow even when the mission is over."

The new study was published online Monday, Sept. 3 in the journal Nature Communications.

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