A few years ago, I asked Freeman Dyson what we should teach our children so there would be more Freeman Dyson's. He gave a surprising answer.
He said we should teach children to genetically "play" with plants. He thought we needed that kind of creativity as a human species if we would ever be able to populate the asteroid belt. He said that most of the surface area of the solar system is in the asteroid belt -- but the only way we could really live out there was if we could create warm blooded plants.
Freeman at his best [1] when he is thinking blue thoughts [4,5] in the blue plane.
Thermogenic plants have already evolved [2]. We need to make them grow an anti-desiccant film and be more efficient like living stones [3].
Isn't the large total surface area of the asteroid belt overwhelmed by drawbacks like unusability of most of it for most purposes (uneven, unstable, unshielded, etc.), and the fact that humans do really poorly in microgravity?
Those drawbacks are only true on some (possible) timescales. The biggest drawback currently, for human settlement of the asteroid belt, is that we can't afford to send anyone there!
Freeman Dyson's the person after which the Dyson sphere is named, so the current (relative) "unusability" of asteroids or the fact that humans currently seem to "do really poorly in microgravity" are 'just' additional obstacles to be overcome sometime in the future from the perspective in which space megastructures are possible.
One question I really hope we can answer someday: exactly how little gravity do humans need before it becomes too "micro"? Can humans stay healthy on Mars? On the Moon? On Ceres or Enceladus or Pluto or Charon or yet smaller bodies?
But yeah, I don't think "surface area" is the right angle to look at. More like "volume within a sufficient depth". A lot of (most?) asteroids and comets consist primarily of water ice, and water happens to be pretty darn good at radioactive shielding, so if we build habitats inside the asteroids we'd have a solid chance of significantly addressing that particular hazard (and also have plenty of water for drinking / agriculture / fuel).
The second part of this story is that he said he was inspired by the Little Prince. Specifically, the low gravity Wells, making it possible to jump from planet to planet ..
He said we should teach children to genetically "play" with plants. He thought we needed that kind of creativity as a human species if we would ever be able to populate the asteroid belt. He said that most of the surface area of the solar system is in the asteroid belt -- but the only way we could really live out there was if we could create warm blooded plants.