Windblown Sky

Windblown Sky

Habitable. It’s just a word, a concept simple enough for anyone to grasp. It means you can step out of an airlock without a helmet and not die. But there’s habitable and then there’s habitable. Most of what we find are marginally habitable worlds. Sure, you can step outside without a helmet and you won’t die. At least not right away. But that little qualifier doesn’t mean that you want to live there.

I mean our dear old Earth, paradise that it was, probably only qualified as habitable for the last eighth of its existence, and even then it went through some rough spots – even before we arrived on the scene. There are exceptions, like Eden, Paradise and Kalmar – even Delphi if you ignore the predators – but most of what I’ve seen are marginal worlds, places where the local life might be well-adapted and flourishing, but where we would huddle under burning suns, foul air or angry skies.

The gas giant moons are often the most marginal. They generally fall into two types: little water worlds that might just have an island or two and small dry worlds with shallow seas and windblown skies.

- Rebecca Severn, Eighty-Seven Planets, A Memoir.