[ben_w]

Third option, we can take advantage of repeated gravitational slingshots to transfer orbital kinetic energy from Jupiter to Earth via an asteroid going repeatedly between both planets, gradually increasing Earth's orbit.

(I'm not an astrophysicist, I just read about this idea a few years back and it stuck in my mind).

[AprilArcus]

The limit on earth's habitability is determined by permanent sequestration of atmospheric CO₂ through the carbonate-silicate cycle, not insolation. Once CO₂ drops below a certain level, photosynthesis will no longer be possible and all remaining ecosystems will collapse.

(Don't mistake that as an endorsement of burning fossil fuels — climate change is operating at a rate measured in decades, CO₂ drawdown via the carbonate-silicate cycle operates at a rate measured in hundreds of millions of years)

[ben_w]

True, I had forgotten that. But I assume we can fix that over this kind of timescale.

[plasticchris]

I guess Jupiter would be more efficient but it would be really neat to do this to mars bringing it nearer to the habitable zone/earth