New solutions for mystery concerning Saturn moons could shed light on one's might, Enceladus, support life, researchers say. For example, researchers may now know why Enceladus is a hidden ocean harbor while many of her brothers and sisters are not.
Saturn only has amazing circles, but it also has over 60 moons. These natural satellites vary in size from small spaces less than 1000 feet (300 meters) wide to the t Huge Titan, which is larger in diameter than the Mercury planet. Many of these moons rotate far from the circular planet, but others have been inserted into the circles.
Many have remained a mystery about the origin and evolution of Saturn's greatest inner moons: Mimas, Enceladus, Tethys, Dione and Rhea (listed in order of diameter, mass and increasing distance from the planet). Scientists had expected densities and structures of these moons to be dependent on their mass or distance from Saturday, but a spaceship that analyzed them proved unexpected that this is not the case.
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Previous research suggested these moons are compatible with rings of remains around Saturn. According to this idea, removing the gravity of the planet would cause powerful tides on these moons which would lead to drowning and melting, forces that would lead to a heavier rock to sink into cores & # 39 lighter moons and ice to dominate their shells. Tidal effects of such would be stronger when the moons were closer to the planet and weaker as they moved further away over time.
Mimas does not show any geological activity, although this is the majority of these five lunches and so is the strongest tide of Saturday. In contrast, Enceladus is further from Saturn and is experiencing 30 weaker tides than Mimas. However, somehow the tidal forces melt ice within the inside of this moon, leading to a huge underground ocean and "cryovolcanoes" that flow.
Further, Rhea is the largest moon and so the one most likely to keep heat and would help melt its rock and its ice and separate it inside layers. , but previous work suggested that this moon might be mixed mix of rock and ice. In contrast, Mimas, Enceladus and Dione, less than Rhea, have structures of rocky cores and icy shells.
Understanding more about the origin of these geological activities could help to answer questions such as the hidden ocean of Enceladus could support life. "Basically, what excites me is looking for life beyond the Earth," said lead author Marc Neveu, a planetary scientist at the NASA Goddard Space Flight Center in Greenbelt, Maryland, by Space.com.
To solve the puzzles these moons pose, scientists would like to model the effects of tides on the geology of the moon. However, simulations of the tides that cause tides operate at daily scales, while simulations of geology usually operate at millions of years. So previous work usually picked one method or the other, modeling a geology or modeling geology.
In the new study, however, researchers designed computer models that were simulating the geological changes and the simpler orbital effects that these moons might have proved over a 4.5-billion life. Saturn-year.
The scientists found that tidal forces would lead to sufficient geological activity for the past oceans or the present within Enceladus, Tethys and Dione. Enceladus still has an underground ocean, because its gravitational interactions with other moons such as Tethys and Dione keep its orbit relatively uneven. And the constant variation due to the strength of Saturn's gravity removal changes the level of the shape of the Enceladus shape regularly, flexible and interior heating of the moon.
"This is the first explanation consistent with returned data. T Cassas NASA spacecraft about how little light like Enceladus, which is as big as the state of Washington or the British Isles, has an ocean surface when other brothers and sisters' moons are no more closer to Saturday, and so are more likely to have such seas, is, "said Neveu.
The researchers also found that Mimas was likely to form 100 million to 1 billion years ago; if older, interactions between Mimas and Saturn rings would have led to that moon to a higher orbit than it is at present. The young age of Mimas means that the moon would have formed after all the radioactive material present at the formation of the solar system some 4.6 billion years ago had rotted. Because of this, its pubs would have started too cold and difficult for tidal forces to heat a lot.
"When ice is warmer and more bitter, it becomes more responsive to tidal forces that are deforming it," Neveu said. "Mimas did not have the minimum amount of heat to start in order for tidal forces to trigger running heating."
In terms of why Rhea pubs are not separated into layers, "there is some uncertainty in the measurements of the Cassini spacecraft inside Rhea, so the deeper layers may be inside. more rocky and the more close tiers, "Neveu said. t
Overall, these findings suggest that the hidden ocean of Enceladus is about 1 billion years old. "One billion years is enough for life to come to the obvious – 1 billion years after the Earth was born, there was life," Neveu said. At the same time, "1 billion years means that there can still be enough chemical activity between the rocky core of Enceladus and its ocean to provide energy for any potential microbial life, similar to the energy. T The Earth's chemical at the seaside helps to maintain ecosystems there, the ocean is not too young and not too old, it can be the right age for life.
Neveu warned that a key constraint on this research was that he had made simplifications that could have affected his accuracy. "We didn't calculate the high tide and the low tide that each of the five moons tested at the same time every few hours for 4.5 billion years – to make that right, take about 20 years on a desktop computer, "he said.
In the future, the scientists want to emulate more complex scenarios, incorporating more features about Saturn and its satellites, such as how the planet might have won moons that were rushed away or which conflicted with other moons, says Neveu.
The scientists were detailed their findings online April 1 in the journal Nature Astronomy.