The idea that there are cosmic cats sounds, at least, low-budget science fiction film. But it is not necessary to go to the cinema of series B to hear about astromininos: they do not have mustaches or maúllan, but already there is a whole cat horde orbiting Saturn.
What they do have are names like Garfield, Socks, Whiskers and Blandito. Elected by the scientists of the Cassini mission, the appellations do not correspond to any kind of extraterrestrial being, but to a group of small satellites and celestial objects that occupy one of the outer rings of the gaseous giant.
Thus, the cat names they receive are in fact affectionate pseudonyms invented by scientists to replace the actual astronomical denominations of satellites, rather more boring. Gloves, for example, are officially called Alpha Leonis Rev 9.
The spacecraft's instruments, which disintegrated last month into the atmosphere of Saturn, have revealed the existence of at least 60 of these tiny moons during the more than 13 years that has lasted the voyage of the probe. Those responsible here on Earth have been baptized with cat names because, they say, they also have several lives and come and go in their own way.
These space minors are in the F ring - the hoops are named after the different letters of the alphabet - one of the weakest and thinnest of the system. It is not a solid structure, but consists of particles containing ice water with sizes ranging from the barely perceptible dust to rocks of several meters in diameter.
His technical appellations derive from phenomena known as occultations, which occur when one celestial body completely covers another when interposed between him and an observer, appearing larger in the latter's eyes. This is how Cassini unveiled the presence of small objects: when they were placed before a star.
Their shadow gives them away
Thanks to the probe's ultraviolet spectrograph, scientists from the UVIS experiment (from the 'Ultraviolet Imaging Spectrograph') can detect light variations by passing through the particles of the rings and appreciating the opaque silhouettes of tiny, invisible moons for the cameras because of their small size.
The sophisticated instrument has allowed them to observe more than 150 concealments throughout the mission under lead researcher Larry Esposito, who discovered Saturn's F-ring in 1979 while working for NASA's Pioneer 11 mission.
In a study published in 'Icarus', the team describes the three main categories in which they classify the bodies they encounter. First, consider moons or satellites smaller than those with a solid consistency; second, the group of 'icicles' includes those somewhat smaller aggregates that pass part of the light; Finally, they call 'nuclei' light variations that are not associated with any mass that meets the criteria for belonging to the feline family.
But cats do not belong to a category throughout their life: the particles change shape because there are abundant clashes between them that can cause the disintegration of some or the union of others. In fact, some may grow so much that they emerge from the ring and become real moons: Esposito and his colleagues have found that bodies are especially dynamic in the area near Prometeo and Pandora, the two satellites closest to the F ring, with which may be related in some way.
Although scientists continue to study and baptize these objects, none will witness their evolution. There is no longer a spacecraft orbiting Saturn and, even if there is in the present or there is in the future, it is practically impossible to re-detect the same bodies again among the millions that surround the planet. We will not know what will become of these Gloves, Garfield and Cosmic Socks now that they have escaped.
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