True for all the Galilean Moons more or less. Their orbits all lie within the Jovian equivalent of the Van Allen belts. And Jupiter's magnetic field is much stronger than earth's.
Not Callisto. Being within Jupiter's magnetosphere but out of reach of Io's shenanigans makes it one of the mildest radiation environments in the solar system.
Io is in orbital resonance with Europa and Ganymede, which causes its orbit to be slightly elliptical. Due to Jupiter's immense gravitational field strength, Io experiences a very high changing tidal force, which causes a changing stress and strain on the entire structure of Io, which causes tidal heating due to friction. This makes it by far the most volcanically active body in the Solar System. Its surface is regularly completely resurfaced, and is covered in sulfur compounds.
Jupiter and Io have a very interesting symbiosis. Jupiter melts Io to form dusty volcanos. It then magnetically sweeps Io clean of dust. The dust forms a plasma ring that enhances the same magnetic field.
> What about rocks in the surface of the water?. Some volcanic rocks can float.
This is... not something you lay plans on. Even on Earth, these rocks are formed at surface pressure, just barely float, and don't float for long (I've tried). If they form in the deep ocean, I'm guessing the pressure isn't going to let the bubbles be big enough to create bouyancy at all. Either way they would be super rare.
I am realy excited for the Findings on these missions. Altough I am still missing an Enceladus mission because enceladus is among the most fascinating ocean worlds.
> This remarkable transformation in our understanding is the result of just three missions: Voyager, Galileo, and Cassini—along with some computer modeling and hard staring by the Hubble and Webb space telescopes.
Seems odd to neglect to mention New Horizons immediately after mentioning the probable existence of liquid oceans under Pluto's surface, a finding made possible thanks primarily to New Horizons.
No shade on New Horizons intended, but I was talking about the early 2000's revolution in understanding of ice moons/ocean worlds, and that preceded the Pluto flyby by a lot.
It was a valuable piece of corroborating evidence, but not shocking and unexpected in the way results from those three missions were. We had good reason to believe Pluto would look a lot like Triton, and it does.
Fair enough, though how common was that belief that Pluto would look like Triton? Before the first photos from New Horizons pretty much every artistic rendition of Pluto I'd seen was a solid ball of rock and/or ice, more like Ceres than Triton.
Both were known to be Kuiper Belt objects, so it was expected there would at least be a family resemblance. I don't think anyone expected Pluto to be more active than Triton; that was certainly a surprise.
If there are planetologists reading the thread, I'd love to hear a more authorative perspective than mine!
> Enceladus is far smaller than the Jovian ocean worlds, roughly the size of Ohio
Why not just say 'has a diameter of about 500 km'? The propensity of astronomers to compare diameters of a small spherical object to a surface patch of a much larger spherical object is intriguing. Similar things happen with 'the Great Red Spot is about two Earths wide'.
miohtama | a day ago
> The radiation environment around Europa is punishing; an astronaut standing on the surface would get a fatal dose in about a day
kaseijin | a day ago
idlewords | a day ago
Io, meanwhile, is 35 Sv/day. Location really matters among the four Galilean moons.
sennalen | a day ago
stackghost | 5 hours ago
delta_p_delta_x | 2 hours ago
gorgoiler | an hour ago
Jupiter and Io have a very interesting symbiosis. Jupiter melts Io to form dusty volcanos. It then magnetically sweeps Io clean of dust. The dust forms a plasma ring that enhances the same magnetic field.
pvaldes | a day ago
> We want rocks in contact with water,
But there is ice compressed between the water column and the xenoceanic bottom, ok. I see the problem.
What about rocks in the surface of the water?. Some volcanic rocks can float.
Gravityloss | 13 hours ago
andrewflnr | 12 hours ago
This is... not something you lay plans on. Even on Earth, these rocks are formed at surface pressure, just barely float, and don't float for long (I've tried). If they form in the deep ocean, I'm guessing the pressure isn't going to let the bubbles be big enough to create bouyancy at all. Either way they would be super rare.
exhilaration | a day ago
voxelghost | 2 hours ago
merek | a day ago
Europa Clipper, launched 2024, starts Europa flybys on March 2031
Dragonfly, hopefully launching July 2028, arriving on Titan 2034
https://en.wikipedia.org/wiki/Europa_Clipper
https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe)
mastermage | an hour ago
yellowapple | a day ago
Seems odd to neglect to mention New Horizons immediately after mentioning the probable existence of liquid oceans under Pluto's surface, a finding made possible thanks primarily to New Horizons.
idlewords | 9 hours ago
It was a valuable piece of corroborating evidence, but not shocking and unexpected in the way results from those three missions were. We had good reason to believe Pluto would look a lot like Triton, and it does.
yellowapple | 7 hours ago
idlewords | 6 hours ago
If there are planetologists reading the thread, I'd love to hear a more authorative perspective than mine!
3eb7988a1663 | 5 hours ago
delta_p_delta_x | 57 minutes ago
> Enceladus is far smaller than the Jovian ocean worlds, roughly the size of Ohio
Why not just say 'has a diameter of about 500 km'? The propensity of astronomers to compare diameters of a small spherical object to a surface patch of a much larger spherical object is intriguing. Similar things happen with 'the Great Red Spot is about two Earths wide'.