poly: Von Neuman Culture density functions(was: Is our lightcone is uninhabited except for us?)

At 09:55 PM 12/15/97 EST, you wrote:
>
>In a message dated 12/15/97 7:25:11 PM, jamesr@best.com wrote:
>
>>Consider the possibility that the fastest means of space traversal is
>>through a wormhole/blackhole-ish means. However, your technology really
>>only allows you to exploit these phenomena in a fairly limited fashion
>>(i.e. you can use them, but you can't make them or control them to any
>>significant extent). Your civilization has decent sub-c capability, but
>>nothing too fast because of the resource requirements and potential for
>>accumulating damage.
>
>Even "slow" speeds are pretty fast at the timescales under consideration.
>A culture expanding at .001c still fills the Milky Way in 100 million
>years, less than 1/100 the age of the universe. If there's anybody
>out there, they're basically hiding - using Dyson spheres radiating at
>barely above background radiation, and deliberately leaving a wide
>variety of stars uncolonized.

I am not so certain that we necessarily should have been crossed by a sub-c
Von Neuman culture. We don't have the slightest idea of what the
distribution of such cultures should be, but this information is necessary
to make such a calculation. The younger the universe, the less likely that
a culture has had time to occur, therefore yielding a much sparser
distribution. Consequently, the odds are better that you don't have such a
culture in you back yard to begin with, but it also gives them more time to
find your backyard. The older the universe, the more time such cultures
will have to occur, but they will have expanded over a much smaller area.
If the older cultures were distributed in a sparse enough fashion and
traveled at sub-c velocities, I find it very reasonable that we haven't
been found (yet).

In short, we need to know the probable universal density of sub-c Von
Neuman cultures as a function of time before we can accurately guess
whether or not we should have been found by such a culture yet. If the
slope of the density function is small enough, we could reasonably assume
we haven't seen a Von Neuman culture because they have not had the
opportunity to reach us, or in the extreme, don't exist.

I will leave wide open to conjecture as to what this function might be.

-James Rogers
 jamesr@best.com
Received on Tue Dec 16 03:44:53 1997