starship-design: Fermi, again . . .

[Curtis Manges <clmanges@worldnet.att.net>]

	Just got the percolation theory paper today, and it doesn't seem to
account for the comparative density of stars closer to the center of the
galaxy, as opposed to where we are, out closer to the rim. This could be a
factor to consider. Colonization has a purpose, after all; it's a search
for more living space and/or resources, and those are going to be more
abundant and therefor easier to get to at the center; there will be more
choices within a given radius of home. Time taken to use those up before
expanding further could slow the process. If things get crowded and wars
break out over the more closely-spaced territories, it could further slow
expansion. 
	Still, given the time involved, they should have been here by now, and
there's no reason to assume that life wouldn't develop from about the same
starting time throughout the galaxy.
	Consider also that, in a more densely-populated area, there could be a
higher turnover rate in colonization, especially in the case of territorial
conflicts, and that would likely reset the clock, so to speak, for a
colonization cycle.
	More to chew on . . .
	Curtis