In 1610, Galileo Galilee turned his telescope towards Jupiter and discovered something incredible. What initially appeared like stars surrounding the planet were, in fact, natural satellites! These four satellites, Io, Europa, Ganymede, and Callisto, were named the “Galilean Moons” in his honor. With the dawn of the Space Race, our knowledge and fascination with this system has only deepened. While Jupiter has countless moons and moonlets (95 and counting!), the Galileans are not only the largest but have some pretty unique features as well.
Io is a volcanic moon composed of silica and metals, with mountains on its surface higher than Everest and over 400 active volcanoes, some of which spew lava 400 km (250 miles) high. Europa and Ganymede are frozen worlds largely composed of water ice and volatiles but which have warm and salty oceans in their interior. Callisto is an icy moon covered in massive craters and ringed features, the largest being Valhalla (3000 km; 1864 mi) and Asgard (1400 km; 870 mi).
Since 1979 when the Voyager 1 and 2 probes passed through the system, scientists have speculated that there could be life beneath Europa’s and Ganymede’s icy surfaces. Similarly, science fiction writers and scientific organizations have speculated how humans could live on some (if not all) of these moons with the right strategies, technology, know-how, and precautions. Therefore, living among these moons would present tremendous opportunities but also challenges and ethical considerations.
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I remember reading the Hope Study at some point in my own research. I still really like the idea of making our base on Callisto and exploring the other Galilean moons remotely. It seems safer that way, both for us and for any alien organisms that might be living on Europa or Ganymede.
Though that does assume there’s no life on Callisto. Also, I don’t think I heard anything before about what happens when Callisto passes through Jupiter’s magnetotail.
Callisto still sounds like the best option to me, just with a few more precautions and safety measures than I originally thought.
Well as long as they have shelters underground (in the ice sheet, how cool would that be?), Callisto and even Ganymede are totally doable. Europa is another matter, requiring six feet of ice overhead at all times. But that could still allow for some really funky settlements in the “air pockets.”
The air pockets thing is pretty neat. I hadn’t heard anything about that before.