[mahart]

Biotech is still in its infancy and mastering DNA would open up a new frontier where humans can edit the genetic code to what makes a human. Assuming it isn't universally banned.

The only truly depressing future to me is if interstellar travel really is as hard as it seems to us now. There kind of needs to be a physics/propulsion discovery on the order of magnitude of electricity or the journey can only be feasibly made by the immortal AI robot race that replaces us.

[Robotbeat]

Interstellar travel IS hard, but the current laws of physics allow it to be done. Crewed interstellar travel can be done on timescales of ~50 years to the nearest star system using ~10Terawatt of solar power in space to power efficient beamed macron propulsion with the benefit being that most of the investment is in the macron beamer and power supply which stays in the solar system and can be reused like once every few months, sending a stream of ~100 ton spacecraft on magsails to Alpha Centauri (using the magsails to brake against the interstellar medium near the destination). Two way trips are not feasible in a human lifespan as it currently is, but one-way settlement of nearest stars is, with a stream of supplies and settlers arriving every few months.

To really make this feasible, improvements in hibernation tech could help. Induced torpor over a week or two already works and could be used repeatedly so that psychological time in transit is only a few years (and the reduction in metabolism from torpor may also extend calendar life of the crew, but that is not yet proven). Even modest life extension (i.e. increasing healthspan from ~mid-60s to mid-80s or longer) would significantly increase the viability of human settlement of Alpha Centauri, and we're just getting to grips with the biochemical tools needed to fight aging, so who knows over a few centuries what will be possible. I think increase in human healthspan and lifespan is more likely than a dramatic practical but fundamental physics breakthrough cutting down the time.