Comment by Reubachi

Comment by Reubachi 4 days ago

5 replies

Amazingly, yes, in a few ways (the mechanics are possible). But no in as many ways. (Fuel, sustainability, tracking)

The greater barrier is that the nature of the expansion of the universe prevents any real interstellar travel that has a "destination" in mind. Of course we might have some "FTL" or "near light speed" travel in futre, but if the universe is expanding infintely from every point in space at light speed, how could we ever "catch up" to objects we see even now?

jandrese 4 days ago

If your travel involves the Rocket Equation the answer is no. If you are limited by the speed of light and the lifetime of human civilization then the expansion of the universe is not an issue. Traveling between nearby solar systems is very close to impossible, traveling between galaxies is outright impossible.

  • OkayPhysicist 4 days ago

    The lifetime of human civilization problem is an odd one, because due to relativity, one-way trips are not an unsurpassable hurdle ( 2-3 generations on a 1 G spacecraft to get pretty much anywhere). But you can't come back, because it's basically guaranteed there'll be nothing left for you to come back to. Because while it might take "only" two hundred years from the passengers perspective to reach the edge of the (current) observable universe and come back, they'll be arriving 90 billion years in the future.

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mr_toad 4 days ago

The objects you can (eventually) reach are proportional to your speed. For example at half light speed you could catch up to objects nearly halfway to the Hubble Horizon, about 7 billion light years away.