X-Message-Number: 11201
From: Thomas Donaldson <>
Subject: RE: ETs and reasons for their (non)existence
Date: Mon, 1 Feb 1999 00:08:25 +1100 (EST)

Hi everyone!

A few cents on the ET issue.

First of all, it's easy to think of all kinds of reasons why we cannot 
see/interact/understand them. Yes, those reasons will also have to somehow
explain why they haven't done any reengineering on galactic scales, etc --
AND why they aren't clearly visible here on Earth.

Basically all such ideas, because they basically propose that the ETs
are not visible/provable by any means we now have, come close to taking
a religious approach to them. If you want to believe those ideas, I cannot
convince you otherwise, almost by definition.

HOWEVER, here are some astronomical facts which may bear on the issue of
ETs (with a few biological facts thrown in too):

1. We have observed no sign of the existence of ETs ANYWHERE. At the same
   time, sufficiently advanced ETs could easily reengineer their Solar
   System and even the stars nearby. If they are at all technological
   in the way we are technological, we'd expect them not only to do 
   that but many other things.

2. Among the things such ETs might do is to make themselves immortal. And
   once they do that, there's no special problem to colonizing the 
   Galaxy.

3. If ETs came into existence, the span of time within which they could
   come into existence is at least half a billion years. The Galaxy,
   including stars with enough heavy elements to make planets such as
   the Earth, have existed long enough  --- even before the Sun existed
   --- for that to happen. So why aren't they here?

4. Recent studies of planets around other stars suggest that solar systems
   such as ours may be much more rare than formerly thought. Hence planets
   supporting life, not to mention intelligent life, will also be much
   more rare. As to other forms of life, with intelligence we can indeed
   create them, but the overwhelmingly likely form that might come into
   existence without being directly created would have a chemistry similar
   to our own. Not identical, but at least based on C, H, and O.

5. Less recent studies suggest that planets such as the Earth retain their
   habitability by NATURAL, NONTECHNOLOGICAL means for a much shorter time
   than once thought. The time window available for evolution of ETs
   may therefore be much shorter than previously thought. And yes, at
   some stage in their history, ETs must have evolved from some other
   creature, which would have been extraterrestrial but not intelligent.

6. Even if a planet bears enough life to match the Earth, say 50 million
   years ago, there is no special force or reason to believe that it must
   inevitably develop any form of intelligent life. Evolution does not
   work in any special direction, and we have no more reason to believe
   that intelligent beings are inevitable than we have to believe that
   (say) elephants (ie. elephant-like creatures) are inevitable.

All these are reasons to believe that ETs do not exist anywhere near us
ie. anywhere reachable by spaceships in less than (say) 1 billion years.

This does not mean that we should not fund efforts to search for signals
from ETs, etc etc. Searching is an experiment. The above is theory.
However it is theory based on what we observe and have observed, and thus
should have more weight than contorted explanations of why ETs exist
despite the total lack of observations of them.

And incidentally, it does make a suggestion for experiment, too: rather
than try to detect signals for stars in our Local Group, try to detect
signals from galaxies much further away.

And as I said, if you really want to believe ETs exist, then it's easy to
leave the range of things experimentally verifiable and come up with
many different ways they can exist and not be observed. But don't claim
to yourself that you are doing science.

		Best and long long life to all,

			Thomas Donaldson

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