Imagine transporting Jupiter to the orbit of Earth.

Jupiter wouldn't change much - the cloud tops would be a tad warmer and the weather a bit more dynamic, but that ain't much.

What would be really interesting is that all the Galilean moons would melt. The rocky component would gather as a ball at the centre and a deep ocean would exist - ideal for Marine life.

Over millennia, the ocean would gradually boil away to space - largely by hydrogen escape, but even the oxygen and nitrogen would go slowly.

The result - a watermoon with a thin atmosphere. - "So long and thanks for all the fish!"

I don't think that technological civilisation could ever develop on ths moon - no fire, no metal smelting, no electricity (unless you use electric eels!). No radio telescopes, no computers, no space rockets.

But you could have advanced and even intelligent life, living in coral cities with seaweed-stalk spear hafts and flint tips. (Maybe I should never have watched "The Little Mermaid")