The recent confirmation of a planet circling our nearest stellar neighbour is nothing short of thrilling. Sure, it isn’t habitable, circling Alpha Centauri B in something like 3.2 days, but the fact it exists at all is a major breakthrough. If we can find a few more planets over there, we might seriously start thinking about actual space exploration. Kudos to the European Southern Observatory team for making the discovery, and having the scientific self-discipline to spend three years confirming it before the announcement.
So, what are the realistic considerations of a potential interstellar mission? In my opinion, the barriers are enough that we won’t be doing it for a very long time, if at all – barring some black swan scientific discovery like a warp drive or other FTL technology. No doubt we have much to learn about physics and the universe, but we cannot assume that future scientific discoveries will help us indulge our urge to explore.
One of the biggest barrier to such travel is time. If it takes 100 years to reach another star, nobody is going to want to go. And if we might find nothing of worth and have to set off somewhere else, the incentive is too small to bother, especially assuming a significant cost in energy and resources to send a viable ship that far and for that long.
So, how can we address the time barrier? Nobody wants to live our their lives (and the lives of the next 40 generations) in a spaceship – there haven’t been many human societies that have lasted anywhere near that long. But what if a human lifespan was dramatically longer, even functionally immortal? It seems unlikely now, but no more so than warp drives and wormholes. In fact, we spend significantly more resources and energy studying health than we do on space.
A thousand-year old person, or a person who might live for 10,000 years, might be much more willing to undertake an interstellar voyage. It is hard to know what humans would be like if they had lifespans on that scale, but I imagine patience would be much more common. Some people would no doubt appreciate an opportunity to spend a few centuries working on something that interests them. Maybe they could finally finish the Harry Potter novels, or read those impenetrable Tolkein books that aren’t LOTR.
The other big barrier to interstellar travel is cost. Not in dollars but in resources and energy. It will take a lot of energy to send even a tiny ship to another star, and a lot of resources to support even a tiny crew for thousands of years. And the more resources needed, the more energy as well, a vicious cycle that could well make interstellar travel impossible.
However, there are some resources that weigh nothing, like technical and scientific knowledge. Far better to send a few small machines capable of making anything on arrival as needed than to try to send everything in advance. Similarly, it would be a lot easier to send some raw materials for the manufacture of humans on arrival (i.e. genetic material and the means to grow and educate people when they get there). Trying to send actual grown humans might be impossible and absurdly expensive, but sending a tiny ship with all it need to build on arrival might actually be viable.
Of course, we don’t have the scientific knowledge to build a person from scratch right now, but we much closer than we are to an FTL drive (if such a thing is possible). It may be that humans who arrive at another star will be born of that star, and any further exploration would be similarly done by their descendents. Von Neumann Machines, but organic.
All of this is a long way off, barring the black swan event that changes everything. (My personal favourite would be friendly contact from somewhere else once we reach a certain level of development). Nonetheless, the discovery of planets in the neighbourhood makes me optimistic that someday, someone will go for a closer look.