Re: SETI Microprobes and Interstellar Travel

Richard Burke-Ward (
Fri, 10 Sep 99 10:27:25 +0000

David -

>You don't seem to be describing microprobes here.

Fair point. Microprobes are a subset of the potential range of probe
types. Macro should also be considered. I foolishly conflated the two.
Microprobes could hitch rides on comets too, though.

>However, in general, I don't think one should ignore technical problems
>and hope they go away. On the other hand, once you have properly
>quantified them, you can find solutions for the consequences (whether
>that means better designs of outgoing probe, or a shift back to
>electromagnetic modes of communication).

I do agree that quantifying problems is valuable. It is thebest basis for
projection. My point was, rather, that we should not consider all ETI to
be limited by the current state of our technology. For a start, *we*
won't be limited by our current technology in a few years... There is a
difference between assessing the challenge posed by various factors (eg,
relativistic particles), and assuming that the challenge is
insurmountable, and therefore even considering probes is pointless. It is
this latter position that I have a problem with. As I said, my points
were not directed against you.

Let's by all means assume we have defined the mathematical limits of the
universe - accelerations, relatvistic effects, limits of matter... This
may help us define the parameters of a probe - limits on size, lifetime,
speed, and so on. The point is, that these limits do not preclude probes
being here. Right here. Ok calculation will define how difficult it is -
but I have yet to see anyone actually come up with a reason why it is

And this is given what we *already* know about the universe, and on
projections of our own technology. The idea that every instance of ETI in
the last several *billion* years has got as far as our calculations and
then just given up on the whole idea just seems crazy.

We have had fuel-based machine technology for around 200 years. We have
had information technology for around 100 years (Jacquard loom, etc -
excluding the Babbage engine). We have had ballistic rockets for 50
years, and manned spaceflight for 30 years. We already regularly surmount
engineering challenges which were deemed impossible by earlier
technological generations. Are we really prepared to say that the limits
of *all* possible technologies are already within our sights (we've
always been wrong when we've claimed that before)? And that despite the
fact that such probes seem physically possible even to us - in the
earliest nanoseconds of our technological infancy - no civilisation
anywhere has *ever* bothered during the thousands, hundreds of thousands,
millions of years of their technological maturity?

So, yes: let's define challenges, quantify the limits of interstellar
probes, use our knowledge of the universe to define the limits of the
possible and probable. And then let's *use* that data to design ways to
search for probes. Because to do otherwise may well be to ignore SETI's
best chance at success.


This archive was generated by hypermail 2.0b3 on Sun Oct 10 1999 - 15:46:34 PDT