"Future spacecraft missions will search the feathers for signs of life, many of which will only be affected by the eruption process," said Washington University astrophysicist Lucas Fifer, who breaks hundreds of springs from the ocean into space through cracks in Enceladus & # 39; ice-covered surface. provides a tantalizing glimpse of what the moon's underground ocean might contain. "Understanding the difference between the ocean and the cloud will be a great help."
Scientists did not know why Enceladus is the brightest world in the Solar System or how it related to its E-ring. Cassini found that both the fresh coating on the surface and the frosty material in the E-ring are from vents connected to a global saltwater background that may contain hydrothermal vents.
In the springs complex organic molecules were discovered. The data was sent back to Earth by the Cassini-Saturn orbiter, which ended its service over the Ringed World on September 16, 2017.
Blown away by Enceladus – "The only body beyond the earth with all the demands of life as we know it"
Enceladus is a small moon, an ocean world with a diameter of 500 kilometers. The salty subterranean ocean is of interest for its similar pH, salinity, and temperature as the Earth's oceans. Water vapor clouds and ice particles – discovered and probed by the Cassini spacecraft – erupting hundreds of miles out of the ocean into space through cracks in Enceladu's ice-clad surface, provide a tantalizing glimpse of what the moon's subterranean ocean might contain and possibly offering favorable conditions According to recent research by University of Washington planetary scientists, the presence of such high concentrations could provide fuel for living microbes – a sort of chemical "free lunch", said lead researcher Fifer, a UW graduate student in geospatial and space science , Or it could mean "that there is hardly anyone who eats it."
The new information on the composition of the Enceladus ocean gives planetary scientists a better understanding of the ocean's ability to absorb life. Said Fifer.
But Fifer and colleagues found that the springs do not chemically match the ocean from which they erupt at a speed of 800 miles per hour. The eruption process itself changes its composition. He collaborates with ESS faculty members David Catling and Jonathan Toner. They will present their work on June 24 at the astrobiology conference AbSciCon2019 in Bellevue.
Fifer and colleagues say the feathers provide an "imperfect window" for the composition of the global subterranean ocean of Enceladus, and the composition of feathers and oceans could be very diverse. This, they say, is due to the fractionation of the feathers or the separation of gases, which tends to break some of the feather components while leaving others behind.
Against this background, the team returned to the data from the Cassini mission A computer simulation that takes into account the effects of fractionation to give a clearer idea of the composition of the Enceladus' internal ocean. They found "significant differences" between Enceladus' cloud and the chemistry of the oceans. In earlier interpretations, the presence of hydrogen, methane and carbon dioxide in the ocean was underestimated.
"It's better to find high gas concentrations than none," Fifer said. "It's unlikely that life would consume this chemical-free lunch if the gases were not abundant in the ocean."
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These high carbon dioxide levels also imply a lower and more earth-like pH in the Enceladus ocean than previously shown. This is also a good sign of a possible life, said Fifer.
"Although there are exceptions, most life on Earth works best when you live or consume water at near-neutral pH. Therefore, similar conditions could be encouraging on Enceladus, "he said. "And they make it a lot easier to compare this strange ocean world with a familiar environment."
There could also be high levels of ammonium, which is also a potential fuel for life. And although the high concentrations of gases may indicate a lack of living organisms to consume everything, Fifer does not necessarily mean that Enceladus has no life left. It could mean that microbes are not present in sufficient quantities to consume all available chemical energy.
Researchers can use gas concentrations to determine an upper limit to certain types of possible lives that might exist in the icy ocean of Enceladus.  Strange feathers of Jupiter's Europe – "Unlike Saturn's Enceladus, if they exist at all"
In other words, "Given the fact that so much free lunch is available, what is the largest amount that life can eat to the amount we still see leave? " How much life would that support? "
Thanks to Cassini, we know about the ocean of Enceladus and the types of gases, salts and organic compounds that are present there. If we examine how the feather composition changes, we can learn more about this ocean and everything in it.
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