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What do we do if SETI is successful?

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174 points leephillips | 1 comments | 20 Oct 25 17:13 UTC | HN request time: 0.304s | source
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kulahan ◴[21 Oct 25 20:23 UTC] No.45661201[source]▶
In the end, I kinda... don't care. Look up - there's nothing. There should be at least some alien civilizations trying to make their presence known. There should be some signs somewhere that could be recognized universally as either "stay away" or "come here". It really should be trivial to locate technological civilizations unless you've got some incredibly solid reason as to why EVERY SINGLE ALIEN CIVILIZATION IN THE UNIVERSE acts a certain way. Color me doubtful.

We have billions and billions of data points showing the Universe is empty. We have exactly one (1) data point showing it isn't. And that's us.

Besides, just look at the timeline. The universe has only been cool enough, with enough stable stars, with enough formed planets for potential life to form for a few billion years. Between that and the Drake equation, life alone is likely to be unreasonably uncommon. Life that forms after a planet becomes stable, doesn't have any planet-altering disasters, evolves to complex multicellular forms, evolves some kind of intelligence, becomes social, forms a society, advances technology, and starts exploring the universe...? Why bother? The math doesn't work.

Note: I'm not speaking about any KIND of life existing, I'm speaking about technological civilizations. My belief is that we are essentially the forerunners.

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bluGill ◴[21 Oct 25 21:19 UTC] No.45661855[source]▶
When you look up remember that the majority of what you see is in the same sub-arm of the spiral arm of the milky way that we are in. Of those we can see a large number or binary systems - two stars orbiting each other. We fancy telescopes we can see a lot more of course.

All the power of stars, and most of them still are not powerful enough that we can see them even on a dark night! What chance does any alien have of sending a message that reaches us if the light from their star isn't even powerful enough to be easy to detect? It was suggested elsewhere that even if we find an alien, we probably cannot respond if they are more than 100 light years away just because we can't get a message out powerful enough that they can detect (I can't verify this claim but it is reasonable)

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1. kulahan ◴[21 Oct 25 23:11 UTC] No.45662952[source]▶
It's probably worth considering that across a sufficiently large distance, they effectively no longer exist. Their signals haven't reached you, and with the increasing speed of the universe's expansion, they will never reach you. Eventually, everything will be expanding at well beyond the speed of light, so short of being able to cut through space and time, we're not reaching any of these destinations. For all intents and purposes, they don't exist for us. We'll never see any evidence, nor could we ever see any evidence.

So in reality, there is a maximum distance we need to consider - the distance where any signal would have any chance of reaching a detectable region.

But besides, this still misses the most important part. Until 10 billion years ago, stars were much too big and poor in metals and unstable. We didn't have an earth until 5 billion years ago. It was inhospitable to life for a LONG time. We've only had multicellular organisms of any kind for 800M years. Our star is unusually calm, meaning we don't have to worry about being bleached every 5 million years or whatever.

I've said this a couple times in this conversation, but the best guess is honestly that we're the forerunners.