Which is another non-theme, but trying to find a theme for J proved quite impossible (though the odds are I’ll think of something after hitting the publish button…
Anyhow… Jupiter is the largest planet in our solar system with a mass two and half times that of all the other planets combined (according to Space Facts). Its primary makeup is gas, and it is therefore known as a Gas giant. Thanks to a visit to an observatory with the children the other week, I got to see Jupiter and four of its moons through one of their telescopes.
It has a total of 63 moons, but the main ones are: Europa, Lo, Ganymede and Callisto
Some fiction exists with Jupiter as a backdrop, although earlier works, such as Micromégas (1752) by Voltaire and A Journey in Other Worlds (1894) by John Jacob Astor IV take place on Jupiter itself, something discoveries since then have discounted as impossible, due to its having no solid surface on which to land, high radiation and high gravity.
A search of Amazon shows there are quite a few independently published science fiction books with Jupiter as a setting/backdrop, with titles such as The Jupiter Paradox, Jupiter Rising and The Lost Jupiter.
In contrast to this, three of the four moons mentioned appear to be a far more likely place for mankind to reach out to (in science fiction at least).
A search on Amazon of independent books featuring Europa, Ganymede and Callisto turns up a search result in the thousands, mostly relating to a colonisation environment (well on the first page anyway), with Europa being the most popular destination.