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Comment by Dumblydorr | Hacker News Reader

The vast distances between solar systems means that in order for life to expand beyond our system, it must either be put dormant for decades of interstellar travel, or it must travel in a craft so fast that modern physics thinks it unlikely. Since there's little reason to suspect that c speed of light is not the speed limit, that leaves us with some sort of biological suspension of life forms until they reach their destination. This tech is still extremely nascent, but to me there is possibility in at least sending seeds, microbes, probes, and very small crafts to nearby stars.

Nevertheless, it seems likely that we will expand heavily within our own solar system before we ever reach another star. Proxima centauri is light years away, but mars, venus, the asteroids, and various rocky moons are within our grabby reach.

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What if aliens live on a different timescale than us, such that blinking their (presumably proverbial) eyes takes centuries? The speed of light suddenly feels a lot faster!

And why would these life forms need to be biological? Do they need to have a limited lifespan? Could they send their consciousness in a droid? There seem to be options!

Re: your last point, that's something I find the most realistic; Von Neumann probes (https://en.wikipedia.org/wiki/Self-replicating_spacecraft), self-replicating robots that spread across the universe, possibly carrying traces of the civilization that once built them.

"What if aliens live on a different timescale than us, such that blinking their (presumably proverbial) eyes takes centuries? The speed of light suddenly feels a lot faster!"

I think it's reasonable to assume that natural selection wouldn't favor that timescale.

For one, cosmic catastrophies - and resulting extinction events - would be much more often from the perspective of a "slow motion" lifeform.

On the other hand, from the perspective of "super fast living" creatures the universe would appear as a much more peaceful and friendly place.

I'm not sure that's true. While you don't end up with lightspeed expansion, if you get to the point that you have the tech to live on an "iceball" by extracting the hydrogen and fusing it for energy, and can make the rest of what you need from raw atoms and energy, you can just sort of... keep expanding out into the oort cloud indefinitely, until after a while, you're not in the solar system anymore, and even more eventually, you're in another one. The more we learn the less empty interstellar space looks.

That's certainly slow expansion, but it would be an expansion that in relatively short order would greatly exceed the biomass and biodiversity of Earth's biosphere, until it would be quite absurd that the whole thing would simultaneously decide to just stop one day. It would be slow but as difficult to stop as the biosphere is today.

This does depend on some sort of practical fusion tech, though.

Remember though that as you approach the speed of light, relativity starts to kick in with your time "slowing down". In other words, the inverse relationship between speed and time could allow civilizations to expand faster than it would seem possible at "normal time" speeds. Complete conjecture on my part, just a fun thing to think about!

This is true but the amount of energy needed to reach speeds where time dilation makes your journey seem short are just unfathomable.

You're forgetting option 3, and IMHO the most likely option. We become a space native species that inhabit an armada of ships. Colonizing planets beyond mars will very much be a secondary, optional objective. I think in a millennia, the number of humans living in o'neil cylinders will far outnumber the humans living on planets.

This is the modern version of 1700s common wisdom: "A vehicle would have to be much too light to travel through the air. Otherwise it would need an unfathomable amount of energy. And if it tried to go too far up, it would enter the ether!"

Advancement seems to grow at exponential rates. Perhaps in a 1000 years we will not see c as an impediment.

I don't think we're that many decades from being able to send frozen eggs, sperm, microbiome and food production capacity in a spaceship.

When you're near the target, fertilize in an artificial womb, raise the kids with Khan Academy v999, and let them land the ship when they're ready.

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