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What do we do if SETI is successful?

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174 points leephillips | 2 comments | 20 Oct 25 17:13 UTC | HN request time: 0s | source
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Animats ◴[22 Oct 25 07:49 UTC] No.45666012[source]▶
The real question is whether faster-than-light anything is possible. If not, which is what physics has been saying for a century, then we probably don't have to worry about anything further than 20 light years away. If we pick up something from the other side of the galaxy, it's probably harmless. Arecebo was potentially able to communicate with a similar dish at galactic range.

In the neighborhood, there are 83 stellar systems within 20yl, and most have been looked at reasonably thoroughly. There are about a dozen plants in the habitable zone among them. If there's something that could affect us, it's probably one of those stellar systems. Most likely Kepler-90.

None of them seem to be talking using RF.

There probably is life out there, but spread so thinly that civilizations don't interact.

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sgt ◴[22 Oct 25 09:01 UTC] No.45666483[source]▶
You're too focused on human lifespans. If you disregard short lifespans, then intergalactic journeys well below light speed (think 0.1c, 0.2c) is perfectly feasible for such a civilization. Humanity will get there too, with post-biology.

That doesn't necessarily mean we become machines, but we will have machines augment us.

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1. jbstack ◴[22 Oct 25 10:19 UTC] No.45667012[source]▶
> If you disregard short lifespans, then intergalactic journeys well below light speed (think 0.1c, 0.2c) is perfectly feasible for such a civilization

They're feasible even with short lifespans with the use of generation ships. Or with suspended animation technology. Given that all three possibilities (life extension, generation ship, suspended animation) are already considered within the realms of possibility by humans (even though we haven't solved any of them yet), it seems a very flawed assumption that no other civilization could solve any of them.

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2. vee-kay ◴[24 Oct 25 03:32 UTC] No.45690472[source]▶
The short lifespan is an issue only for species with a fast metabolism. Advanced alien species could have some unique biology (maybe capable of withstanding extreme environmental conditions), and they may have a slower metabolism that allows them to live longer.

On Earth itself, some animals or birds such as Greenland Shark, Bowhead Whale, some species of Tortoises (e.g., Galapagos Tortoise), Macaw, Arctic Tern, Koi Fish can live a long time (more than a hundred years).

Ocean quahogs are bivalve mollusks known for their impressive lifespans, often exceeding 500 years.

The immortal jellyfish, scientifically known as Turritopsis dohrnii, is a unique species capable of biological immortality. It can revert to its earlier life stage after reaching maturity, effectively allowing it to avoid death and potentially live indefinitely. This unique ability is due to a process called transdifferentiation, where its cells transform back into a polyp state. Despite its ability to revert to an earlier life stage, Turritopsis dohrnii is not truly immortal. In nature, it can still fall prey to predators or succumb to disease. Thus, while it can theoretically avoid death through regeneration, individual jellyfish can and do die under various circumstances. Researchers are fascinated by Turritopsis dohrnii for its potential insights into aging and cellular regeneration, which could have implications for human health and longevity.