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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

#111

Post by tpoacher »

AnimalMuppet wrote: post #68
tpoacher wrote: post #38

Wa there really such a big need for such a clickbait title? Now I'll never know what it was about. Probably someone selling stuff.

You could either read the article or read the comments. (If there aren't any, wait until there are and read them.) But don't do what you did, which is make a completely uninformative comment. Even if the article is clickbait, and therefore a waste of everybody's time, don't add to the waste with comments like yours.

On the contrary. If the author sees my comment and the clickbait was unintentional, then they'll be informed of its grave consequences.

On the other hand, if it was intentional, then they'll be informed that it doesn't necessarily work as expected.

You might as well claim that "The Social Dilemma" was spam because you can just choose not to open facebook today.

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

#112

Post by sliken »

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…

Given the nature of 3D expansion and the size of galaxy vs the age of the universe 0.1c vs 1C isn't really that big of a difference.

However I do wonder why the fermi folks get all bent out of shape about not seeing other civilizations. How far do you think you could see a fusion or antimatter ship accelerating or deaccelerating from 0.1c? Unless they are zipping around our solar system (Expanse style) doesn't seem likely the we'd notice them.

If the aliens were curious about us and had detected our expanding RF emissions they might well be close by listening.

Seems far from clear that civilizations would bother messing with stars (that would be detectable from a decent distance) instead of just propagating to other solar systems. People are already talking about sending probes to our nearest star via laser propulsion.

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

#113

Post by RobinHanson »

xvedejas wrote: post #35
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…

I understood the "close to the speed of light" really meant something much much smaller than 0.1c, since on cosmological timescales the difference between the first radio signals and domination from an alien civilization could be millions of years, and that'd still be an instant compared to the time before and after the event. So I'm assuming for the fermi paradox to work out here, we'd not need speeds anywhere near…

0.1c isn't slow enough to solve the empirical puzzle that we don't now see alien volumes. That is the fact that pushes for higher speeds in our analysis.
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