Interesting astrophysics development in our solar system with astrobiological implications: the rings and inner moons of Saturn, everything closer than Titan, may be young, forming between 100 million and 1 billion years ago rather than at the dawn of the solar system.
Recent measurements of Saturn’s moon system suggest that it evolves due to tides quicker than was previously believed, with moons moving ourwards more rapidly due to bigger tidal bulges on Saturn transferring more energy. This would explain the large quantity of heat pouring out of Enceladus and powering its geysers and oceans. Tidal forces go down with the cube of distance so closer moons should move out much faster than further moons. Using new figures one can trace back the orbits of the inner moons and see that they should have hit various orbital resonances during the history of the solar system as the ratios of orbital periods changed, which would have left imprints in the system in the form of effects on the rings and changes to the orbits of the moons that we see no evidence of. Conclusion is the system is younger than the age at which backtracking would produce those events, with age limits based on estimated tidal evolution rates. The authors favor tidal evolution estimates that place the age closer to 100 million years than to a billion years, and think a previous inner moon system went unstable and ground itself to rubble in a series of catastrophic impacts before reforming into a new set of moons and rings.
If true this makes Enceladus (one of these inner moons) even more interesting from an astrobiological perspective. Not only is it geologically active with chemical energy sources and an ocean spewing its guts into space where it is easily sampled, but it could be a look at a place that is very young compared to other such places in the solar system.
Interesting astrophysics development in our solar system with astrobiological implications: the rings and inner moons of Saturn, everything closer than Titan, may be young, forming between 100 million and 1 billion years ago rather than at the dawn of the solar system.
http://arxiv.org/abs/1603.07071
Recent measurements of Saturn’s moon system suggest that it evolves due to tides quicker than was previously believed, with moons moving ourwards more rapidly due to bigger tidal bulges on Saturn transferring more energy. This would explain the large quantity of heat pouring out of Enceladus and powering its geysers and oceans. Tidal forces go down with the cube of distance so closer moons should move out much faster than further moons. Using new figures one can trace back the orbits of the inner moons and see that they should have hit various orbital resonances during the history of the solar system as the ratios of orbital periods changed, which would have left imprints in the system in the form of effects on the rings and changes to the orbits of the moons that we see no evidence of. Conclusion is the system is younger than the age at which backtracking would produce those events, with age limits based on estimated tidal evolution rates. The authors favor tidal evolution estimates that place the age closer to 100 million years than to a billion years, and think a previous inner moon system went unstable and ground itself to rubble in a series of catastrophic impacts before reforming into a new set of moons and rings.
If true this makes Enceladus (one of these inner moons) even more interesting from an astrobiological perspective. Not only is it geologically active with chemical energy sources and an ocean spewing its guts into space where it is easily sampled, but it could be a look at a place that is very young compared to other such places in the solar system.