Mimas was discovered by astronomer William Herschel on September 17, 1789.
Saturn's moon Mimas, as of January 24, 2022, is con2idered the smallest of the existing celestial bodies that have a rounded shape due to their own gravity - this satellite does not exceed Spain in area. Also, as of 01/24/2022, scientists have made an assumption that Mimas may be a unique object with liquid water under the outer shell.
There are several hypotheses for the existence of liquid water on Mimas.
First hypothesis: Heating from Saturn's gravity could melt the ice on Mimas from the inside, suggesting an entire ocean on Mimas. Modeling by the Southwestern Research Institute in the United States showed that this hypothesis could be confirmed: the internal heat of Mimas is enough to keep water in a liquid state at a depth of about 28 kilometers under the icy surface.
Second hypothesis: "The amplitude of the Mimas libration, which occurs with a period of 0.945 days (an anomalistic period of revolution), turned out to be almost twice as large as expected. This may be due to the presence of a dense elongated core or a global subsurface ocean. The latter is unlikely, since the energy from the decay of radioactive elements in the bowels of Mimas would not be enough to melt the ice; in addition, there are no signs of any geological activity of its interior on the surface of the satellite. But the authors of the discovery do not exclude that the existence of the ocean can be maintained by tidal heating provided by the eccentricity of the orbit."
The name Mimas was given by the discoverer's son John Herschel in 1847 in honor of the giant Mimas from Greek mythology.
The names of all seven then-known satellites of Saturn, including Mimas, were suggested by William Herschel's son John in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope.
The low density of Mimas (1.15 g/cm³) indicates that it is composed primarily of water ice with a few rock inclusions. No substances other than ice have been found on its surface (as of 2014). Due to the action of the tidal forces of Saturn, Mimas is significantly elongated: its long axis is 9% larger than the short one (the dimensions of the satellite are 415.6 ± 1.0 × 393.4 ± 1.0 × 381.2 ± 0.6 km). The elongation of the satellite is clearly visible in the images transmitted by the Cassini automatic interplanetary station.
The rules for naming the details of the relief of Mimas were approved by the International Astronomical Union in 1982. The details of the relief are given names taken mainly from the British legends of King Arthur and the Knights of the Round Table as recounted by Thomas Malory (the novel Le Morte d'Arthur). This is due to the fact that the discoverer of Mimas, William Herschel, was a British scientist.
The craters are named after the characters of the legends, and other relief details are named after the geographical objects mentioned there. The exception is the largest crater, Herschel, named after the discoverer of the satellite. In addition, some canyons were named after geographical features that appear in the myths about the titans. This is motivated by the fact that the satellite itself bears the name of the giant Mimant.
As of 2021, 42 Mimas surface features have their own names. These are 35 craters, 6 canyons: Pangea (length 150 km), Camelot (150 km), Avalon (120 km), Eta (110 km), Pelion (100 km), Ossa (95 km) and one chain of craters - Tintagil ( length 55 km). Most of these objects were named in 1982 (in 2010, the Tintagil Canyon was renamed the Tintagil chain), and 6 craters were named in 2008.
Mimas is notable for a huge impact crater, which was named Herschel in honor of the discoverer of the satellite. Its diameter is 130-140 km (a third of the diameter of the satellite), the height of the walls is almost 5 km, and the greatest depth is 10 km. The central hill rises 6 km above the bottom of the crater. If a crater of proportional dimensions were on Earth, its diameter would be more than 4000 km, which is almost equal to the length of the territory of Russia from north to south.
The impact that created Herschel Crater appears to have nearly split Mimas apart. The cracks visible on the opposite side of the satellite are probably formed by shock waves that have passed through its body. The surface of Mimas is littered with smaller impact craters, none of which are comparable in scale to Herschel.
Using images from the infrared camera of the Cassini spacecraft in 2009-2010, researchers were able to measure the temperature on the surface of the satellite. The resulting image reminded astronomers of an image of a 1980s computer game character, Pac-Man.
© NASA / JPL/GSFC/SWRI/SSI
On September 1, 1979, the NASA spacecraft Pioneer 11, flying past Saturn, approached the satellite at a distance of 104,263 km. In 1980, the robotic probe Voyager 1 passed Mimas at a distance of 88,440 km, and Voyager 2 in 1981 at a distance of 309,990 km. Since 2005, Mimas has repeatedly photographed and examined the Cassini robotic spacecraft.
