[extropy-chat] Dark matter and ET

[Dan Clemmensen]

Eliezer S. Yudkowsky wrote:

>
> That seems to be based on a frequent-life model... which I suppose is 
> appropriate, if one thinks there is a Fermi Paradox to explain.  I had 
> been thinking more in terms of trying to grab as large a 3D sphere as 
> possible before running into the borders of another expanding 
> species.  If we assume that intelligent life originates at a 
> sufficiently fast rate, without a gradual start in the maturation of 
> worlds, that, even traveling at lightspeed, sufficiently many 
> intelligent species mature simultaneously that each galaxy is divided 
> up into many volumes... hm.  I suppose simple discount rates might 
> then have an effect on the expected brightness of galaxies, even 
> though other aspects of the utility function are irrelevant!  In that 
> sense, I accept the correction.
>
> Even so, what use are stars?
>
> And with life 3.85 billion years old on Earth, and the Milky Way 
> 100,000 lightyears across, how likely is it that more than one 
> intelligent species arises in a galaxy before the first species takes 
> over the whole galaxy?
>
An SI will expand beyond its natal solar system only if The NPV of the 
knowledge gained by use of the extrasolar computational power exceeds 
the NPV of the computational resources to be invested in the expansion. 
Example: the SI might expend an asteroid's worth of comptutronium to 
colonize a star system 4 light-years away.  Using a speed-of-light 
probe, at best is takes 4 years to initiate the colony, and at best the 
colony starts with a knowledge base that is four years old. The SI will 
not get any new input for at least eight years, and the new input will 
be four years old and will be based on an eight-year-old knowledge base. 
The SI may very well conclude that it will gain more knowledge by 
incorporating the asteroid's worth of compturonium within itself rather 
than launching the probe. If this is generally true, then we would not 
expect to see any expanding spheres. Instead, we will simply see systems 
going dark.