Since NASA’s Cassini spacecraft has returned from its mission with photographs of the huge geysers of Enceladus, Saturn’s natural satellite, scientists are still somewhat surprised at the amount of water hiding beneath its frozen surface.
“We, of course, knew that Enceladus had water in a certain amount, but did not know that there was so much of it. It's good that we now have this information, ”said the chief scientist at the Cassini project of the Boulder Science and Space Institute in Colorado, Caroline Porco.
During the study of small accumulations of water on the satellite, the scientists came to the conclusion that these were not separate fields, but a whole frozen ocean.
How did they know this? Due to the small cyclic vibration, which somewhat affects the uniform rotation of the object. Scientists have noticed that more powerful vibrations are being made, and not on any particular area, but on the whole cosmic body. Conclusion: the outer ice shell is separated from the core by a large layer of liquid. Previously, the researchers were simply convinced that Enceladus has a couple of “pockets” of water on the surface, but there were no assumptions about the presence of the ocean and, all the more, evidence of its existence.
The first hint at the presence of large accumulations of water under the frozen surface layer was very interesting data on gravity made in 2013 and 2014, when the Cassini spacecraft passed near the south pole of a natural satellite.
“These data indicate a stronger polarity of the sea about 22 miles below the main surface. Perhaps this is due to the fact that the world ocean in this place has a thinner layer, ”said Porco.
Now an independent analysis confirmed this theory. Computer models show that, as expected, the solid core is separated from the ice surface by a large layer of liquid.
“If the surface was more tightly connected to the core, the vibrations would be much weaker,” said Matthew Tiscareno, a leading scientist at the SETI Institute of California in the United States. “This proves that there is a large water layer between the core and the surface, which is commensurate with the world's oceans,” he said.
“However, to get more information, you need a longer time to observe and calculate, but we are confident that we will eventually achieve the truth,” said scientist Peter Thomas of Cornell University in New York.
As it turned out, the remaining liquid was not frozen, it is not yet known. There is an idea that the tidal forces of Saturn can generate more heat inside their satellite than previously thought.
Now the Cassini spacecraft is given the opportunity to once again pass by Enceladus on October 28 at a distance of 30 miles from it.
Water vapor, carbon dioxide, methane and some ammonia residues were also found in the geysers.
“These findings clearly indicate the presence of extraterrestrial aquatic environment on Enceladus,” said Porco.