In some ways Europa is the queerest little sphere in the Solar System, and for many years it was believed to be quite uninhabitable. It is, too, as far as seventy per cent of its surface goes, but the remaining area is a wild and weird region.
This is the mountainous hollow in the face toward Jupiter, for Europa, like the Moon, keeps one face always toward its primary. Here in this vast depression, all of the tiny world's scanty atmosphere is collected, gathered like little lakes and puddles into the valleys between mountain ranges that often pierce through the low-lying air into the emptiness of space.
Often enough a single valley forms a microcosm sundered by nothingness from the rest of the planet, generating its own little rainstorms under pygmy cloud banks, inhabited by its indigenous life, untouched by, and unaware of, all else.
The image is just a stock NASA photo of Europa, to which I've added the cracks from a mud flat, coloured green, plus some blue for water etc. I'm not 100% happy with it at full size, I don't think it conveys the idea of a mountain-filled depression well enough, but reduced in size to the sort of dimensions it'll be on the page, less than a third of the width of the text field, it doesn't look too bad. Any suggestions for improving it would be gratefully received, of course.
Maybe I should have it the other way round, with surface terrain surrounding bigger blobs of green? Might give that a try.
later: At kayshapero's suggestion I tried adding a mountain texture (from Google Earth) rather than the mud flat - this has indeed worked a LOT better
Any further suggestions from anyone?