May the 4th be with you, and a happy unofficial "Star Wars Day" to all.

Just a quick question for you to ponder, and the question is this: Why do alien worlds in Star Wars - and not just in Star Wars but in sci fi books and movies generally - always have monoclimes?

Which is to say, why does the action always take place on an ice planet like Hoth, or the forest moon of Endor, or the desert world Tatooine?

Image: A whole planet like this? No thanks. Source: Pixabay.

And it's not just Star Wars. The classic 1965 novel Dune was set on the desert world Arrakis. The moon Pandora in Avatar seems to be ubiquitously forested. Star Trek' Mr Spock comes from the hot, arid planet of Vulcan.

Down here on Earth, we've got bits and pieces of all those types of landscapes and climate. Why do our writers and movie-makers imagine monoclimes in space?

There's actually an interesting blog on the official Star Wars site which has a pretty good crack at explaining that.

It argues that weather serves as a device which helps us understand the characters in various Star Wars scenes. (We also argued that weather often plays a role more complex than just a dramatic backdrop to the action in our recent list of the 10 greatest weather movies).

So for example, the desert of Tatooine symbolises desolation.

"The first planet we ever saw in a Star Wars film features prominently in an analysis of weather, as the desert landscape of Tatooine reflects the desolation that Luke Skywalker feels in his life. He feels isolated, alone, and does not have optimism that life will flourish around him," the blog argues.

And the icy planet Hoth symbolises the icy heart of the Empire.

"Since ice is essentially frozen water, and water symbolizes change, viewers know that nothing will change for the Alliance unless they thaw the icy heart of the Empire — manifested here on Hoth."

It's all pretty interesting stuff. And while we can see how giving a planet a monoclime makes things easier from a narrative perspective, we're not sure it makes those planets the most interesting places to live.

Then again, maybe that's not how the force works...