When people learn that energy output from the Sun is increasing, and will boil away the planet’s oceans within a billion years, they wonder if there’s any way to stop the process. Obviously, we can’t stop the Sun from shining and increasing its energy output. But is there a way humans could move the Earth further away from the Sun?
The answer is yes. Well, it’s theoretically possible. Not with today’s technology, and not without an enormous amount of energy, but the laws of physics say it’s possible. In fact, nature does it all the time.
The trick is to replicate a natural process called a 3-body interaction. This is what happens when you have nice orbit perturbed by a 3rd object. In this case, we’ve got the Earth nicely orbiting the Sun. But if we could have an asteroid pass by the Earth in just the right way, its gravity would pull our planet out of its orbit just a tiny bit.
Instead of its current elliptical orbit, the Earth would start to spiral outward from the Sun, slowly drifting further and further away. This is very similar to how the Moon is slowly drifting away from the Earth.
If you timed things right, and used several asteroid passes, you could make the Earth spiral outward as the Sun’s energy output is increasing. Instead of getting roasted, we would slowly drift away from the Sun, matching the expanding habitable zone. This would give life on Earth billions more years, instead of a few hundred million.
Of course, playing pool with asteroids is a dangerous game. Give an asteroid the wrong trajectory and it could crash into our planet and end humanity in an instant. And if you get the calculations wrong, you could end up spiraling the Earth away from the Sun too quickly, and freeze the planet. You’ve got to get it just right.