The Pentagon in Washington, DC, is the largest building on Planet Earth – standing 71 feet (22 meters) high with each of the five sides measuring 921 feet (281 meters) in length. Astronomers studying the mysterious Hexagon which is located at Planet Saturn’s north pole have discovered new data which forced them to increase its measurements – the Hexagon is 20,000 miles (32,000 km) wide and about 180 miles high. If this Hexagon is the headquarters of Planet Saturn’s military, we’re gonna need a bigger Space Force.
Fortunately, astronomers agree that the hexagon is a jet stream moving at about 200 mph (320 km/h) with a circular vortex spinning in the middle. First discovered by the Voyager 1 and Voyager 2 missions in 1980 and 1981, it was believed to only be as high as Saturn’s troposphere (lowest level of atmosphere). Cassini arrived in 2004 and its measurements seemed to confirm that of its predecessors. However, scientists decided to withhold final judgement until Saturn’s spring when the clouds changed to allow Cassini’s Composite Infrared Spectrometer (CIRS) to take better measurements. With Saturn’s year spanning 29 Earth years, spring didn’t arrive until 2009 and low temperatures didn’t allow accurate readings until 2014. (Is Saturn having climate change issues too?)
Nothing happens fast on Saturn, so it took the astronomers three more years of data collection and analysis to find out that that the hexagon is a towering monstrosity.
“As the polar vortex became more and more visible, we noticed it had hexagonal edges, and realized that we were seeing the pre-existing hexagon at much higher altitudes than previously thought.”
In a statement from the European Space Agency, Sandrine Guerlet of the Laboratoire de Météorologie Dynamique in France and co-author of the study published in Nature Communications, described the surprising discovery that the hexagon stands 180 miles tall. It seems hard to believe that a jet stream could maintain such a distinctive shape over such a large area and at such a high altitude, but there it is. Why?
“This could mean that there’s a fundamental asymmetry between Saturn’s poles that we’re yet to understand, or it could mean that the north polar vortex was still developing in our last observations and kept doing so after Cassini’s demise.”
The researchers found that Saturn’s south pole has no such hexagon anywhere at any height. That could mean the poles are different in ways not yet understood. One theory as to how a cloud could maintain such a solid, well-defined shape through multiple levels of atmosheres is a process called evanescence, where waves travel can travel upwards with only minor loss of strength, thus maintaining their shape. But why a hexagon? Lead author Leigh Fletcher of the University of Leicester answers that one.
“We simply need to know more. It’s quite frustrating that we only discovered this stratospheric hexagon right at the end of Cassini’s lifespan.”
Ah, yes … Cassini self-destructed in an atmospheric plunge on September 15, 2017. NASA has future missions to Saturn and its moons planned but none budgeted for. Since Cassini took over 6 year to get to Saturn, we’re not looking at getting new data for a while. Until then, Saturn continues to be the most stylish planet with its iconic rings and its huge polar hexagon.
At least we don’t have to worry about the Saturn Space Force … that will probably come from Enceladus.