Dyson Sphere Candidates from Gaia DR3, 2MASS, and Wise

Yeah, it is highly unlikely to be a Dyson Sphere (or related object), but any follow up scans of those stars could result in some new interesting science telling us why those stars are different from the other ones.

my gut tells me the dyson sphere is easier.

we can sorta-kinda imagine how to make a dyson sphere now, the engineering is just tremendous and our product would kind of suck.

as far as i'm aware we're still pretty clueless about interstellar travel in a human time span.

I would think you someone could build a dyson sphere, it would be the step needed for interstallar travel. The unlimited energy that could be harvested with little effort and channeled.

Perhaps a tiny vessel with huge solar sails being pushed by a stream from the sun?

I have no idea if that makes scientific sense.

I liked the idea in "The 3 body problem" of sending something extremely small

The simplicity of interstellar travel really depends on how you define it.

Constructing a ship of sufficient redundancy / self-repair capability that can carry embryonic life to another star seems like something we could achieve. The engineering problems seem hard but quantifiable, and the resources required are likely available. If humanity decided tomorrow that we needed to put "a human" on another planet, I think it could be done (sent) within a lifetime. (surviving there, another matter)

OTOH the scale of resources that would need to be deployed to begin construction of a Dyson sphere would seem to be immense, let alone the systems required to harness it for anything useful.

A true dyson sphere is likely not physically possible. But superstructures that do the same thing, namely dyson swarms or dyson bubbles, are not particularly hard. If we so desired, we could begin construction of such a megastructure right now. At our current industrial capacity it would take a long time, but hopefully our civilization has a lot of time and industrial capacity ahead of it. Further, such dyson structures begin providing useful results pretty much immediately - it really only makes sense for a civilization to keep building up more and energy collectors over time.

Interstellar travel, beyond small probes to the very nearest stars, is immensely difficult. Either you need propulsion systems that can go incredibly fast like say riding the blast waves of a bunch of nuclear explosions or colliding antimatter that somehow you have; or you need to build things that can survive for extremely long periods (like substantially longer than our civilization has existed) in an extremely harsh environment with no resources for support. Either are hard challenges that require substantial work across many disciplines, and those who devote their lives to carrying out the work will not live* to reap the rewards. And even if a civilization were to put in all that effort, there simply isn't much reward to reap. Certainly if a civilization was sufficiently long lived and advanced they would eventually do this just to say they could, the same way we would climb Everest just because it's there, but there's no way anyone's setting up an interstellar empire before their system's dyson swarm is well under way.

* It is likely that extreme life extension will eventually be developed in one form or another, which should both make decades or centuries long projects much more viable, as well as make longer voyage times more acceptable. But developing such extreme life extension technology is probably comparable in difficulty to the engineering issues of interstellar travel.

There's a book in the bobiverse scifi series that sort of covers this, very entertaining read!

> Which is easier; interstellar travel or building a dyson sphere?

Assuming that we don't know what we don't know, and we need lots of testing and trial-and-error, a Dyson swarm is more doable because we can iterate a design for a swarm node right here in our solar system, until we get it right.

Sending a ship off to a star and then realizing it has design faults is just unfortunate.