The most extensive system of fog layers found on Saturn
US, WASHINGTON (ORDO NEWS) — A wide variety of meteorological phenomena occurs in the vast hydrogen atmosphere of the planet Saturn, which is about ten times larger than the Earth. They help us better understand those phenomena that work in a similar way in the Earth’s atmosphere. Among them, due to its uniqueness, the famous “hexagon” stands out – an amazing wave structure that surrounds the polar region of the planet, and the shape of which looks as if it were drawn according to the pattern.
Discovered in 1980 by NASA‘s Voyager-1 and Voyager-2 spacecraft, it has been continuously observed since then, despite the long and strong cycle of seasons on the planet. Inside this gigantic planetary artifact, a fast, narrow jet stream flows where the winds reach a maximum speed of about 400 km / h. However, oddly enough, the hexagon itself remains almost static; in other words, it barely shifts relative to the rotation of the planet. All these properties mean that the “hexagon” is a very attractive phenomenon for meteorologists and researchers of the atmosphere of the planet.
The discovery was published in the scientific journal Nature Communications.
“Cassini”, orbiting Saturn from 2004 to 2017, took a huge number of images from a variety of distances from the planet and viewing angles. In June 2015, his main camera received a very high resolution image of the planet’s limb, which is capable of capturing details ranging in size from 1 to 2 km. The camera captures a haze located above the clouds that form a hexagonal wave. In addition, the camera used many color filters, from ultraviolet to near infrared, which allowed us to study the composition of these mists. To complete this study, we also used images obtained by the Hubble Space Telescope after 15 days and showing a hexagon not from the side, but from above.
“Cassini’s pictures made it possible for us to find that the hexagon has a multi-layer system of at least seven mists that extend from the top of its clouds to over 300 km above them,” said Professor Agustin Sanchez-Lavega, who led the study. “Other cold worlds, such as Saturn’s satellite Titan or the dwarf planet Pluto, also have layers of fog, but not in such numbers and not so precisely spaced.”
The vertical length of each haze layer is approximately 7 to 18 km, and, according to spectral analysis, they contain tiny particles with radii of the order of 1 μm. Their chemical composition is exotic for us, because due to the low temperatures in the atmosphere of Saturn in the range from -120 ° C to -180 ° they can contain hydrocarbon ice crystallites such as acetylene, propine, propane, diacetylene or even butane in the case of high clouds.
Another aspect studied by the group is the regularity of the vertical distribution of fogs. The hypothesis put forward is that haze forms as a result of the vertical propagation of gravitational waves, which cause fluctuations in the density and temperature of the atmosphere – a well-known phenomenon on Earth and on other planets. Researchers suggest that it is the dynamics of the hexagon itself and its powerful jet stream that may be responsible for the formation of these gravitational waves.
On Earth, waves of this type were also observed, created by a wave-like jet stream moving at a speed of 100 km / h from west to east in mid-latitudes. This phenomenon may be similar on both planets, although the features of Saturn mean that this is the only case in the solar system. This aspect remains the subject of further research.
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