New responses to the mysteries relating to Saturn's suns can shed light on whether one, Enceladus, can support life, say researchers. For example, researchers can now know why Enceladus has a hidden ocean, while many of his brothers and sisters do not.
Saturn not only has extraordinary rings but also boasts more than 60 months. These natural satellites range from tiny lunar widths of less than 300 feet (300 meters) to the vast Titanium which is larger in diameter than the planet Mercury. Many of these satellites rotate far from the circular planet, but others are embedded in the rings
Much remains of the mystery of the origins and evolution of the larger internal satellites of Saturn: Mimas, Enceladus, Tethys, Dion and Rey (listed in order of magnitude of diameter, mass and distance from the planet). Scientists expected the density and structure of these months to depend on their mass or distance from Saturn, but the spacecraft that analyzed them unexpectedly proved that it was not.
Listed: An alien "water world" with complex organic matter
Previous studies suggested that these months merged with garbage rings around Saturn . According to this idea, the gravitational attraction from the planet will lead to intense flooding on these satellites, which will lead to beating and melting, which will lead to the heavy rocks falling into the nucleus of the satellites and lighter ice to dominate their shells. Such tidal effects will be stronger when the satellites are closer to the planet and weaker because they eventually go away.
Mimas does not exhibit geological activity, even if it is the most secret of these ninety months and is thus exposed to the strongest influx from Saturn. On the contrary, Enceladus farther from Saturn and experiences 30 times less influx than Mimas. Nonetheless, one way or another, the tidal forces melt the ice within this lunar interior, leading to a gigantic underground ocean and "cryovolcanoes" that throw away water. Rock and ice and separate it from the interior into layers, but before the work it was assumed that this month could be mixed with a mixture of rock and ice . In contrast, Mimas, Enceladus and Diona, which are smaller than Rey, have structures of rocky nuclei and icy shells.
Understanding more about the origins of the geological activity of these months can help answer such questions as the hidden Enceladus. the ocean can support life. "Fundamentally, what excites me is the search for life outside the Earth," said the author of the study, Mark Neve, a NASA Goddard space flight crew scientist in Greenbelt, Maryland. Scientists would like to simulate the influence of tides on the geology of satellites. However, the modeling of orbits that cause tides, operate on a daily scale, while geological modeling usually operates for millions of years. Thus, previous work has usually chosen one approach or another, simulating the influx or modeling of geology
. Life of 4.5 billion years
Scientists have found that tidal forces will lead to sufficient geological activity for the existence of past or present oceans in Enceladus, Tethys and Diones. Enceladus probably has an underground ocean, because his gravitational interactions with other satellites, such as Tethys and Diones, keep their orbit relatively elongated. As a result, the constant change in the force of gravitational pull from Saturn regularly changes the level of distortion of the form Enceladus, bending and heating the inner part of the Moon .
"This is the first explanation that agrees with the data returned from the Cassini spacecraft NASA on how tiny the moon, such as Enceladus, is about as great as the state of Washington or the British Isles , has an underwater ocean where other satellites are larger or closer to Saturn and, therefore, are more likely to have such oceans, "said Neveu.
The researchers also found that Mimas was probably only 1
"When the ice is warmer and greasier, it becomes more sensitive to the tidal forces that deform it," Neve said. "Mimas did not have the minimum amount of heat to start with in order to get tidal forces to cause heat to escape."
As to why Rhine's internal internal organs can not be divided into layers, "measurements from the Cassini spacecraft in the interior of Rhea have a degree of uncertainty in them, so that there are possible deeper layers of its interior space, and the near-surface layers is more severe, "said Neveu.
Overall, these data indicate that the hidden Enceladus Ocean is about 1 billion years old." One billion years is enough to make life – 1 billion years after the birth of the Earth , there was life, "said Neveu. At the same time," 1 a billion years means that there can still be enough chemical activity between the enceladus nucleus of Enceladus and its ocean to provide energy for any potential microbial life similar to the chemical energy at the seabed of the Earth, helping to maintain ecosystems there. "The ocean is not too young and not too old. It can only be true to life."
Newey warned that the key limitation of this study was that he made a simplification that could affect his accuracy. "We did not calculate the high tides and tides that each of the past thirty months experienced simultaneously every few hours for 4.5 billion years – to do this correctly, it would take about 20 years on a desktop computer," – he said. .
In the future, scientists want to simulate more complex scenarios, including more possibilities about Saturn and its satellites, for example, as a planet may have received the echoes thrown or collided with other satellites [Neveu]. 19659002] Scientists detail their findings online on April 1 in the journal Nature Astronomy