If space really is the final frontier, then it’s likely that some day humans will differentiate their extra-terrestrial colonies with flags – just like we do with countries on Earth today.

What kind of flag might represent Martians of the future? One of the more widely-known unofficial flags was proposed the 1990s, based on the idea of terraforming – the colours are intended to represent the planet’s future path to habitability; from red and barren on the left, to blue and wet on the right.

It’s an interesting idea, but as flag designs go, it is not out-of-this-world.