Why there may be oceans inside dwarf planets beyond Pluto – and what this means for the likely abundance of life
Retrieved on:
Friday, April 5, 2024
In fact, icy moons and dwarf planets in the outer Solar System appear to have liquid oceans below layers of thick ice.
Key Points:
- In fact, icy moons and dwarf planets in the outer Solar System appear to have liquid oceans below layers of thick ice.
- Recent research suggests there could even be oceans inside bodies beyond Pluto.
Tidal heating
- Io therefore overtakes Europa after every two orbits, receiving a regularly repeated tidal tug from Europa that prevents Io’s orbit from becoming circular.
- Peale’s prediction of tidal heating was vindicated only a week after publication when Voyager-1, the the first sophisticated flyby of Jupiter, sent back images of volcanoes erupting on Io.
- This isn’t likely to be due to tidal heating but instead possibly down to heat given off by decay of radioactive elements.
- Saturn has a relatively small (504km radius) icy moon called Enceladus, which has an internal ocean thanks to tidal heating from interaction with the larger moon called Dione.
Other oceans
- Puzzlingly, even for moons that should have no tidal heating, and for bodies that aren’t moons at all, evidence for internal oceans keeps mounting up.
- The authors suggest that heat from the decay of radioactive elements in the rock is sufficient to explain how these internal oceans have been kept warm enough to avoid freezing.
- It is possible that other underground oceans could be similarly inhospitable.
- David Rothery is co-leader of the European Space Agency's Mercury Surface and Composition Working Group, and a Co-Investigator on MIXS (Mercury Imaging X-ray Spectrometer) that is now on its way to Mercury on board the European Space Agency's Mercury orbiter BepiColombo.
- He is author of Planet Mercury - from Pale Pink Dot to Dynamic World, Moons: A Very Short Introduction and Planets: A Very Short Introduction.