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Once we can see them, it’s too late

scottaaronson.com

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Re: Once we can see them, it’s too late

#81

Post by gpsx »

This may be beside the point, but I don't think there is any alien lift out there. I am going to make up number N_life_universes which is the number of universes needed in order for an instance of intelligent life to evolve. Many people seem to assume this much less than one. I think it is much greater than one, meaning most universes you look at will be void of life. I'd also say there are many universes, one source being the rules of quantum mechanics. But I know some people believe in wave function collapse, and if that is true I am not sure what this means for having mulitple universe.

There is a related number, N_hamlet_universes. This is the number of universes needed in order for monkeys to type Hamlet typing as fast as they can, covering every planet spaced 6' feet apart (in case one gets sick). I think this is also a very large number but I haven't figured it out.

Re: Once we can see them, it’s too late

#82

Post by tuatoru »

ndjtjgkglf wrote: post #47
ivalm wrote: post #18

This kind of assumes that a “maxed out” civilization can expand at speed of light, but I don’t think it is given. It may very well be that meaningfully massive transport cannot exceed even a small fraction of c . After all, propulsion has to make energetic sense. 1. There is energy to get to speed 2. Mass of fuel to decelerate (and you have to accelerate that fuel in the beginning!) 3. Highly blue shifted CMB (that a…

In theory you can manipulate atoms and molecules at a distance with light. So you can use a laser beam to construct a 3D printer at a distance. Rinse and repeat, and this is asymptotically expanding at c.

OK, you're tossing out quantum mechanics, in particular the Heisenberg uncertainty principle.

We are firmly in the realm of science fantasy now.

Re: Once we can see them, it’s too late

#83

Post by thesteamboat »

krapp wrote: post #78
thesteamboat wrote: post #77

Earlier quoted context omitted.

From a previous discussion of this paper I took away the following clarifying insight: The Drake equation is usually turned into the Fermi paradox via some estimations that show the average (mean) number of alien civilizations we expect to see is large (>1). However, just because the mean is large does not imply that seeing 0 is low probability. More concretely, suppose there were 10 possible 'parallel' universes. In…

You don't even need to invoke parallel universes. Look at the Hubble Deep Field photo[0]. Our observable universe has hundreds of millions of galaxies. It's entirely feasible for tens of millions of alien civilizations to be spread about and not visible to us in the narrow window of space and time in which we've been looking. [0] https://en.wikipedia.org/wiki/Hubble_Deep_Field

Invoking parallel universes was solely for ease of explaining/emphasizing the math, not because I think it's a realistic model.

Talking about the Hubble Deep Field kind of misses the point. The original Drake equation[0] estimates the number of alien civilizations in our galaxy. I probably should have used galaxies in my example, but left it with parallel universes as that is the common phrase.

[0]: https://en.wikipedia.org/wiki/Drake_equation

Re: Once we can see them, it’s too late

#84

Post by bob33212 »

uxcolumbo wrote: post #70
bob33212 wrote: post #39

Earlier quoted context omitted.

We are within 500 years of creating millions of self sustaining spaceports. We are within 500 years of AGI. We are within 500 years of understanding quantum gravity. We are within 500 years of fixing biological death. The order we get to those and how they interplay and change the world matters so much that it doesn't make sense to worry about making predictions.

What about the climate crisis halting or slowing down technological progress?

Climate change is not a big deal as far as innovation goes. It is an enormous disaster for specific cities though

Re: Once we can see them, it’s too late

#85

Post by oxinabox »

Interstate idea. The title overstated too late though. Following the premise that an expanding civilization is expanding near the speed of light and it's radio will reach us first. We can expect hundreds of years between radio and anything physical.

1) We started producing a lot of radio around 100 years ago. And we are still a long way from expanding at near speed of light. Even with expodential growth in capacity.

2) expanding near speed of light is much less than speed of light. Say 99% of the speed of light. And expanding civilization is probably going to be coming from far far away, just because there is a lot more far far away than pretty close. So say they are comiy from 10,000 light-years away (still close by galactic standards, and incredibly Close by Universal standards). Then the radio they start transmitting when their grown begins has gained on their expansion ba lead of 100years by the time it reaches us

Sure on the million and billion year time-scales mostly talking about that 100+ years is very little but it is still generations.

Re: Once we can see them, it’s too late

#86

Post by AnimalMuppet »

bob33212 wrote: post #76
AnimalMuppet wrote: post #66

Earlier quoted context omitted.

You state these "we are within 500 years" as if they are certainties, but you show no evidence for any of them. The only one I consider even slightly likely is that we are within 500 years of understanding quantum gravity. So... evidence? Argument? Just stating baldly that it is so is not very convincing.

I don't have a time machine so no I cannot prove what will happen in the future

Fine, but you seem to regard it as at least virtually certain. Why? What is your basis for regarding it as close to certain?

Re: Once we can see them, it’s too late

#87

Post by cbushko »

I have not studied this area of science but the article reminded me of the fictional book series The Three-Body Problem by Liu Cixin.

I really don't want to say anything to spoil the books but the series were so good that I devoured them last summer which is something I rarely do.

Re: Once we can see them, it’s too late

#88

Post by ivalm »

kurthr wrote: post #75
ivalm wrote: post #18

This kind of assumes that a “maxed out” civilization can expand at speed of light, but I don’t think it is given. It may very well be that meaningfully massive transport cannot exceed even a small fraction of c . After all, propulsion has to make energetic sense. 1. There is energy to get to speed 2. Mass of fuel to decelerate (and you have to accelerate that fuel in the beginning!) 3. Highly blue shifted CMB (that a…

If you can seed enough intelligence with self replicating "nano-machines", which seems reasonable, then you can accelerate clouds of that material at quite close to the speed of light with high power lasers, much like diffuse solar sails. No need to carry large payloads, reaction mass, or energy... those are at the endpoint where you find them (and convert them into grey-goo?). It's more of a viral mode of expansion…

They still need to decelerate. Even nanomachines will not survive if they hit planets at close to c.

Re: Once we can see them, it’s too late

#89

Post by ivalm »

ndjtjgkglf wrote: post #54
eloff wrote: post #51

Earlier quoted context omitted.

A laser beam expanding out over light years is not a laser anymore and definitely not atom sized.

You are assuming present day lasers. An advanced civilization will individually control the photons. You also don't really need atom resolution anyway. You can build mechanical computers driven by rolling stones by abblating matter with powerful beams - lithography on continent size scale, etc.

They are still quantum objects and still have diffraction and such.
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