We can all name worlds, real or imagined, and as gamers, writers and readers we've probably visited many in some way or other. I set a short snippet of fiction at Neptune a few posts back and suggested a 'retropia' on Triton. That's two, and still real ones.
Worldbuilding can be a big part of writing, roleplaying and wargaming - even if only for a campaign - and in sci-fi really does become about whole worlds. If anyone is building a world from scratch - in however much detail - they could well need a little help. If you're going big, plenty can be found at This Orb, a bold attempt I linked to at the snippet.
Our solar system is of course still the source of almost all the solid knowledge we have. To fill in the gaps that have appeared over the years or get up to date with recent developments, you could do worse than this amateur but highly ambitious animation.
Mercury inspires Mordian, and so gives us the Iron Guard? Well, maybe - and more.
It's strange in our backyards, but so much like home. It's "Little Gidding" by T. S. Eliot.
.And the end of all our exploring
Will be to arrive where we started
And know the place for the first time.