[ad_1]
The hexagon of the north pole of Saturn, in motion, seen by the spaceship Cassini, today disappeared.
Credit: NASA / JPL-Caltech / SSI / Hampton University
A strange, hexagon-shaped swirl formed over the north pole of Saturn as the northern hemisphere of the planet enters in summer, according to data from the international Cassini-Huygens mission. A new study reports that the unusual vortex circulates hundreds of kilometers above the clouds in the stratosphere layer of the planet's ring atmosphere.
This hot polar vortex looks like another previously discovered hexagon formation, also located at the north pole of Saturn, but lower in the atmosphere. But how and if these weird hexes of low and high altitude are related remains a mystery for scientists.
"Either a hexagon appeared spontaneously and identically at two different altitudes, one lower in the clouds and the other in the stratosphere, or the hexagon is an imposing structure covering several hundred kilometers," Leigh Fletcher's study and global scientist at the University of Leicester in England, said in a statement. [Cassini’s Greatest Hits: Best Photos of Saturn and Its Moons]
NASA's Cassini spacecraft arrived at the Saturn system in 2004, when it was summer in the southern hemisphere of the planet and wintering in the northern hemisphere. At the time, the spacecraft documented a circular, hot, high-altitude vortex at the south pole of Saturn, but nothing at the North Pole.
Before Cassini, NASA's Voyager spacecraft had revealed a northeast hex at low altitude in the 1980s. This hexagon is a long wave that would be related to Saturn's rotation, in the same way as the rotation of Saturn. the Earth influences the polar jet.
The Cassini spacecraft has taken a closer look at this previously discovered low altitude hex formation with several instruments, including the Composite Infrared Spectrometer (CIRS), a device that measures the temperature and composition of objects by capturing infrared light.
Cassini's view of the strange hexagonal swirl above the north pole of Saturn.
Credit: NASA / JPL-Caltech / SSI / Hampton University
But as it was winter in the northern hemisphere of Saturn at that time, temperatures in the stratosphere above the North Pole were about minus 252 degrees Fahrenheit (minus 158 degrees Celsius). Celsius) – too cold for reliable CIRS observations. Extreme temperatures have forced Cassini to wait for the summer and, as a result, the high altitude regions of the North Pole of Saturn have been unexplored for years.
"A Saturnian year covers about 30 terrestrial years, so the winters are long," said Sandrine Guerlet, co-author of the study and researcher on planets at the Dynamic Meteorological Library in France. "Saturn did not begin to emerge from the depths of winter in the north until 2009 and gradually warmed as the northern hemisphere approached summer," Guerlet said.
Years later, as temperatures in the northern hemisphere of Saturn gradually increased, Cassini's CIRS discovered the strange polar swirl over the North Pole. "As the polar vortex became more and more visible, we noticed that it had hexagonal edges," said Guerlet.
Cassini captured images of a hexagon-shaped vortex at low altitude and high altitude only at the north pole of Saturn, while the vortex discovered years ago at the south pole of Saturn was circular. This gap between the Saturn poles has led researchers to believe that there are probably different processes at work at both poles of the planet. The various vortices suggest that the poles are asymmetrical or that the North Pole Vortex continues to grow and continued to grow after Cassini's disappearance in September 2017, Fletcher said.
It is unlikely that the newly described vortex will come from a single giant hexagonal column of clouds above the North Pole of Saturn, as the winds of the planet change dramatically with altitude. And Fletcher and his colleagues have already thought that waves, like those in the North Pole hex, discovered earlier, could not propagate upward, and would thus remain trapped in the clouds.
But Saturn has a potential anomaly in wave behavior.
"One of the methods by which information about waves can go up is a process called evanescence, where the strength of a wave disintegrates in height but is strong enough to persist in the stratosphere," Fletcher said. .
The discovery of the mystery of Saturn's swirling high-altitude hexagon formation can help scientists to learn more about the atmospheric effects, for example on how lower events in the atmosphere affect the atmosphere. Environment at high altitude.
"We just need to know more," Fletcher said.
The team released its findings Monday, Sept. 3 in the journal Nature Communications.
Original article on Live Science.
[ad_2]
Source link
