Arguably humanity is already terraforming Earth (and not for the better).
But scientists are already thinking of ways of transforming other planets to make them more liveable for humans.
While we have discovered more than 90 worlds (large moons and planets) in our Solar System, and thousands further afield, we have not yet found one that looks capable of supporting human life.
Which is why scientists are at least interested in the idea of manufacturing liveable worlds by changing the essential make-up of chemicals in their atmosphere.
One of the first (theoretical at this stage) targets is Venus, the hellish world which due to its incredibly thick and hostile atmosphere is actually hotter than Mercury, despite being further from the Sun.
In the most recent examination of the idea, Phys.org's Fraser Cain gives his verdict on the prospect in this entertaining post.
What are the potential strategies? Well, they all sound crazy -- but when your transforming planets that's pretty much a given.
- Massive space-based shades to cool the planet down, then scoop up the frozen carbon on the space and get rid of it in space
- Build floating cities above the planet and suck CO2 from the atmosphere with giant factories
- Speed up the planet's rotation by directing asteroids nearby
Here are some other equally extravagant theories on terraforming the planet:
- Carl Sagan: how to use algae to remove Venus' CO2
- Paul Birch: Flood Venus with hydrogen
- Nobel prize-winner Paul Crutzen: or maybe Sulfur dioxide
So, yes, it's difficult. Terraforming Mars would be far easier -- though still way beyond our capacity. But you never know, when it comes to space it's often the craziest ideas that turn out to be true. Download yourself into a computer in a couple of decades and you might survive the ten or so centuries it could take for this to actually happen.