Re: predictions if wave passed here

From: Eugene Leitl (
Date: Wed Oct 18 2000 - 00:05:06 MDT

Robin Hanson writes:

> To be clear to all listening, one of my main points as this is *not* the
> prediction of the model I developed. Of course my model could be wrong.
Of course, we both are probably totally wrong. It's not that we're
going to go to interstellar seed any time soon.
> my model. Specifically they are how fast resources available can grow
> at an "oasis", how much seeds cost as function of their speed and hardness,

Resources growing at an oasis? The matterenergy concentration in a
given solar system is constant. You can rearrange matter so that you
maximize available energy flux utilization, or even tinker with the
rate of matter to energy conversion. But the total resource
concentration is finite. Or are you talking about new solar system
formation? I'm not sure colonists will allow such a thing. Hydrogen is
probably too useful to be wasted on stellar object formation.

> and what the seed mortality rate is as a function of their speed, hardness
> and distance traveled.
What is the probability of a penny-crossection meeting something
larger than a micron dust grain in transit? Interactions of
relativistic matter is nasty, it doesn't matter much whether this is
0.1, 0.5 or 0.9 c. You have to send a lot of the seeds (you can't
focus the spot well enough anyway), make the individual seeds
distributed (multiple level redundancy), maybe send ahead skimmers.
> My model says that a selection effect at the leading edge selects for
> pioneers who do not stay. So the big question is how strong this

Inoculate an infinite agar plate. Step back a couple of lightminutes,
and wait until the front will arrive. Look just behind the wave. Are
you going to see sterile substrate after wave front? Fat chance.

Staying is default. The launchers can't launch themselves, so they
stay. Sustainable barrage of stellar neighbours with seeds is a waste
of resources after they're infected, so they'll cease.

> selection effect can be in moulding the preferences and strategies of
> colonists.

I think one half of your assumptions is faulty: yes, the selection
effect is very strong, resulting in convergent evolution of expansion
wave front organisms and no, they do not leave sterile substrate in
their wake.

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