[nine_k]

This depends on what do you mean by 'inaccessible'.

Going there and back again, and telling your pals how things are 1000LY away is likely impossible.

Expanding your civilization to more and more habitable celestial bodies, slowly but relatively surely, is entirely possible. This is how e.g. plants colonize vast spaces, being limited by the speed of their growth often by inches per lifetime. (You should also consider the amount of resources the plats dedicate to it, and their success rate.)

[Robotbeat]

Extending human lifespan (perhaps using methods of hibernation, perhaps not) is easier technologically than basically any viable form of crewed interstellar travel.

[harimau777]

I get what you are saying, but it seems like the plant approach is mostly useless to humans. If the people on opposite sides of a galactic civilization are so far away that they cannot meaningfully interact, then it seems like that's no different than the other person not existing from their perspective.

[parksy]

Depends on the definition of useless or meaningful. If meaningfulness only extends to immediate political, social, economic or technological interactions then maybe an organic colonisation seems useless, I guess.

Unlike plants, through the power of electromagnetic communications and a culture based on shared knowledge, humans will know the others exist, even though that interaction will be slow with likely little-to-no-influence on their local evolution.

There would be huge cultural meaning even despite the lack of immediacy. Imagine living in a world where you know that there are other humans like you in space, living on other worlds light-years away. You might not be able to communicate immediately, but you know that they are there, and the universe is not so empty to you. You could look to the night sky and reminisce on your great(*n) grandpronoun whose progeny have built a thriving colony among the stars. Entire institutes would exist dedicated to collating and outlining the historical expansion of mankind among the stars, even if that knowledge takes centuries or millennia to accrue.

Also we can not say those other humans may as well not exist, because there is no telling what each new colony will go on to achieve. Their cultural, scientific and philosophical development independent of the influence of Earth's history and challenged by new environments could yield new perspectives, ways of thinking and practical inventions whose value far outweighs the large delay in communications.

If we're talking galactic scale, then the creatures who ultimately wind up on the other side of the Milky Way two hundred thousand years from now would likely bear only a passing resemblance to the humans who expanded from Earth. However barring a catastrophic event that erases their knowledge of their history, they would owe their existence in their history books to this tiny planet.

Finally, the fear that we are the only planet with human life would be vanquished, so even if we all died from pollution or meteorite, we'd know that somewhere the legacy of our species (and selected companion lifeforms) would continue, which I don't think is useless or meaningless either.

[naasking]

> I get what you are saying, but it seems like the plant approach is mostly useless to humans

Yes, and as humans are to plants, so our space faring descendents will be to us.

[therein]

But aren't there massive gaps where an intermediate celestial body to perform this jump on will be simply too far away for traditional space travel?

[jessriedel]

Probably not. On the timescales of millions of years, the only thing that really matter is whether it's physically possible, and it looks physically possible to colonize other galaxies.

http://www.fhi.ox.ac.uk/wp-content/uploads/intergalactic-spr...

I'd be pretty surprised if the jump between galactic groups is much worse.