Nature has done a pretty good job of making the Earth a habitable place. If it hadn’t, you wouldn’t be reading this right now. Or perhaps you would be, but you wouldn’t be a human and you wouldn’t be on Earth. The point is, we know what it takes to make a planet habitable simple because we’re living somewhere habitable. So, if we wanted to recreate the process elsewhere, what would it take? Here’s how you make a planet habitable:
1. Make sure it’s not too close to its sun - but not too far away either.
When astronomers study distant suns and their planets, they define a region as a “habitable zone” based on the sun’s size and how much energy it puts out. If a planet falls within that zone, it’s potentially habitable. Since we currently don’t have the capability of moving a planet from one orbit in its solar system to another, we have to find planets that are already in habitable zones. Fortunately for us, several candidates have already been found.
2. Give it an atmosphere.
Habitable generally means comfortable in the sense that if you need to wear a spacesuit 24/7 to survive, it probably doesn’t qualify. Humans need oxygen to breathe, so an atmosphere that has oxygen and plenty of it (not too much, of course) is needed. Of course, the planet needs to be capable of retaining that atmosphere, so strong gravity and/or a magnetic field are important components. And unless we could trigger natural processes to create an atmosphere, we would have to generate one artificially, which we currently don’t have the technology to do on a massive scale.
3. Make sure there’s water.
Why does NASA always look for water in the search for life outside Earth? Simply put, water is the basis for life. To survive, and to have a temperate climate, you need water. We would either need to bring in massive quantities of water, or the planet should already have it either in ice or liquid form. There are plenty of “water worlds” out there in their star’s habitable zone, so it’s not out of the question to think we could find something that suits our needs, should it ever come to that.