I'm building a science fiction setting. The present is just like ours.
Some time in the middle of the 21st century, humanity invents technology that allows travel to nearby stars within months. By the year 3000 AD, it is possible even for private individuals to routinely travel to Earth's neighboring star systems. The only drawback is that it takes the better part of a century to build an interstellar "pathway" from one star system to another, so easy travel is limited exclusively to already "visited" stars.
Eventually, in this setting, humanity will start constructing Dyson rings, spheres, shells, and other megastructures. My estimates would be that:
- The first Dyson ring would be feasible around 4000-6000 AD with construction taking a few decades or a century.
- The first Dyson sphere/swarm would be feasible not long afterwards, with construction taking a couple of centuries, expedited a bit by the fact that it can be operational even before completion.
- The first Dyson shell would be feasible near the year 10000 AD (assuming discovery of exotic materials in the meantime), with construction taking several centuries, possibly more than 1000 years.
I would like to know whether my estimates sound reasonable/believable, from a science-based perspective -- and, if not, what would more reasonable estimates look like,