strvgglecity t1_j2ofn1f wrote on January 2, 2023 at 8:59 PM

Reply to comment by Pleasant_Carpenter37 in Pulling together different technologies to make interstellar colonization possible by matthewgdick

How do you grow from a seed bank to feed hundreds of infants (the minimum size for a sustainable DNA population)? Where do the plants grow? In what soil? What water are you using?

All food that goes to space now is dehydrated and they use onboard water to rehydrate it, because it's more efficient and cost effective. There are no canned goods.

Yes, messages that take 9 years isn't interaction. It's extremely slow communication that would have virtually no function.

I consider science fiction, for the purposes of questioning the future, to be based on science. It's also not important and was a throwaway line.

Yes, humans have nothing to gain by sending probes light years away. There is no opportunity for anyone on earth to benefit from that endeavor. The trip would take multiple lifetimes, so unless people are immortal, nobody who sent the ship would be there for or to arrive, AND the technological advances made in the interim would very likely make the previously sent ship obsolete. It's much more likely that we will transition to hybrid biomechanical beings before even attempting to reach another star, and biomechanical beings may have immortality or have lost the need for physical bodies entirely, with the ability to exist on a computer server and be uploaded into various forms once it arrives.

Pleasant_Carpenter37 t1_j2op9vj wrote on January 2, 2023 at 10:02 PM

Hydroponics? Starter pack of bacteria to condition the soil on the new world? Maybe there's already soil there that would be suitable with some prep work? We can't actually get a close enough look to say whether any given exoplanet is a lifeless rock or not. Any such colony ship would surely be preceded by a survey probe, so the robots would draw water from the environment.

And yes, I know they don't send literal cans of soup into orbit. I'm sure you can forgive a convenient turn of phrase even if it wouldn't be part of a technical specification for NASA.

Slow communication is still interaction. If I write a letter and send it to my mother via snail mail, does her response not count as 'interacting'? That seems like a silly way to twist the meaning of the word. That being said, communication with a 20-ish-year latency (now thinking of places like Wolf 359 or Ross 128) would be a different model than what we have now.

Actually, that raises another practical issue. How do you send a coherent signal over such great distances? Directional radio antenna? Laser comms? The power levels and precision needed to make a direct transmission work might not be feasible. OTOH, you could launch relay probes at regular intervals to simplify the problem, so it wouldn't be insurmountable.

There's definitely the risk that an "early" colony vessel would be completely obsolete by time it arrived. I read a story a while back where humanity sent a diplomatic mission to an alien homeworld via a coldsleep ship. While they were having tea with the alien emperor, Earth's first FTL ship arrived! Definitely the kind of stuff that would make some aerospace engineers despair.