? I would have guessed nanotechnology to be the eventual cause
of medical immortality.
Interplanetary exploration is the same level as major genetic engineering? We were walking on other planetoids in the 60s, and exploring other planets in the '70s. And if he's talking about planets outside our solar system, my own bet is that we'd need to be extropian before we'd be able to make the voyage. Maybe I'm just being too pragmatic.
Then again, this is a comfort scale rather than a timeline. Maybe we will soon see the 'futsie's of the Judge Dredd comic books: people who have been driven to a nervous breakdown by their amazement at the incredible technologies of their own time.