From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Fri May 30 2003 - 11:04:34 MDT
On Fri, 30 May 2003 Spudboy100@aol.com wrote:
> 2) Does having a "swiss-cheese" galaxy promote or hinder the
> development of other intelligent species. or neither?
Well we have seen papers that nearby gamma ray bursts are
probably fairly harmful to life as we know it. There was
also a report (this week I think) about the discovery of
some galaxy with a huge density of stars that are or will
become super-novas. This is also probably not good place
for life. So it seems likely that the Earth has not
been exposed to nearby GRB or significant quantities
of supernovas.
But if the so-called "chimney/hole) around us is only a
few million years old then it probably hasn't impacted
the general development of life here too much.
> 3) Would large regions of ionized interstellar gas, affect the propagation or
> detection of radio signals? If so, this would explain Fermi's paradox?
Radio signal propagation interference would more properly be called
upon to resolve the "SETI" paradox -- i.e. "Why haven't we heard
from them yet?" But that can easily be resolved by "Because we
are too dumb to be bothered to communicate with." The Fermi paradox
is more properly "Why aren't they 'here' yet?". The studies in the
article cited (below) might explain that. Even though we might live in
a nice neighborhood ourselves we might live in a "bad neighborhood"
to get to. Traveling at any significant fraction of the speed of light
means you have to deal with running into particles (be they ionized H,
neutral H, or any other atoms/molecules). Its expensive to start a trip
at 0.1c then have to slow down to 0.01c then speed back up to 0.1c.
The "walls" of the local bubble may make it very expensive to get to
us in terms of the cost of matter (ablation of the particle shields)
and energy (having to slow down and speed back up). So we might
effectively be "shielded" from colonization.
A lot more work needs to be done on the various costs (matter and
energy) of interstellar travel and why and how people would do it.
Robert
Background story:
> 2003-05-30
> http://www.sciencedaily.com/releases/2003/05/030530081808.htm
> 3-D Map Of Local Space Shows Sun Lies In Middle Of Hole Piercing Galactic
> Plane
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