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From: gsmith@brahms.BERKELEY.EDU (Gene Ward Smith)
Newsgroups: net.space
Subject: Long-Term Viability
Message-ID: <11986@ucbvax.BERKELEY.EDU>
Date: Sun, 23-Feb-86 08:58:30 EST
Article-I.D.: ucbvax.11986
Posted: Sun Feb 23 08:58:30 1986
Date-Received: Wed, 26-Feb-86 05:01:19 EST
References: <37378.509307074@lbl-rtsg.arpa>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: gsmith@brahms.UUCP (Gene Ward Smith)
Organization: University of California, Berkeley
Lines: 90

In article <37378.509307074@lbl-rtsg.arpa> jef@LBL-RTSG.ARPA writes:

>The only long-term way to assure the viability of Earthlife, including
>whales, gorillas, cephalopods and everything else as well as humans, is
>to get off this planet.  As long as Earth is the only place we live, we
>are vulnerable to extinction.  There are all sorts of nasty things that

  No matter where we lived, we would be vulnerable.

>could wipe out all life on this planet.  A really large comet could hit
>us, pasteurizing the planet.  Sirius could go supernova.  Maybe a new form

  A large, space-going cephalopod could come along and eat the whole planet.
Get serious (pun intended) Sirius isn't going to blow up. Why don't you 
learn some Astronomy if you like space so much? It is very interesting
stuff.

>Furthermore, we have a time limit.  Our sun is getting hotter.  It has been
>getting hotter, very slowly, for as far back as we can measure - billions
>of years.  So far, the biosphere has managed to keep the local temperature
>constant by steadily decreasing the proportion of greenhouse gasses in the
>atmosphere - carbon dioxide, water vapor, methane, etc.  However, if the
>sun continues to get hotter for only another 100 million years, that
>solution will no longer work - even getting rid of every last molecule would
>still leave the planet too hot.  There will be a runaway greenhouse effect
>leaving Earth looking something like Venus.  Not a place you'd want to live.
>
>So, you may ask, why am I worrying about events that won't happen for 100
>million years?  Surely we've got plenty of time to start colonies in the
>asteroids and begin moving out to the stars.

  We've got *more* than 100 million years! In the 10 billion years the Sun
will spend on the main sequence, it will double in luminosity. Most of that
will occur towards the end. The Sun has been getting hotter, but very slowly.
Adaptation to increased heat will proceed much faster. We are still having
ice ages now, so what's the big deal?

>Well, we actually don't have very much time at all - 100 years, 200 at the

  Oh no! An emergency! Call an ambulence!

>outside.  Humans have been using up the natural resources of this planet
>at an amazing rate, and now we're running out.  Soon we're going to have
>to fall back to a low-energy, renewable-resource, labor-intensive way of
>life.  I have two objections to this.  One is the immediate loss of life.
>Ecotopia can't support five billion people.  Maybe one billion.  That
>means four billion people must die - which is about fifty times more than
>have died in all wars so far combined.

  And space colonization, even if successful, would not prevent it. Birth
control might.

>My second objection is that if we go to a low-energy life-style now, we will
>never be able to reverse that decision.  The easy resources are gone.  The
>close-to-the-surface ores, the coal, the oil - we've used it up.  Now it
>takes high-tech energy-intensive machinery to extract the resources needed
>to keep the high-tech machinery going.  We can keep going like this for
>a little while longer, but if we give up high-tech we won't be able to
>start again.  We would have to wait for continental drift to expose new
>ores, which would take a hundred million years or so, and by that 
>time - you guessed it - runaway greenhouse effect.

   I'm confused -- do you have a high faith in scientific and technical
advancement, or a very low one? It seems you adopt either point of view
to suit your convenience.

>So, if we back off now, we are putting a permanent, irrevocable ceiling on
>the number of human individuals who will ever live.  One billion people
>for 100 million years means at most five times ten to the fifteenth people
>will ever live.
>
>If, on the other hand, we spread Earthlife to the stars, then the next
>100 million years will see the birth of at least ten to the twenty-fourth
>humans, plus unguessable numbers of intelligent descendents of the gorillas,
>dolphins, octopodes, etc.

   Oooh --- it sounds so easy! We'll just roll out to the stars (THATS not
hard) and live forever. Why do I find it strange to think that if you have
just proven it impossible to do on the earth, it should be so easy somewhere
else?

   Why is there so much unmitigated bullbleep on net.space? Is this some kind
of obscure religious cult I haven't heard about? I thought space colonization
was a possibility technology could offer us -- if we used our knowledge and
planning ability. Some of you seem to think you are going to wish yourself to
Epsilon Eridani. "If you wish upon a star ... "

ucbvax!brahms!gsmith    Gene Ward Smith/UCB Math Dept/Berkeley CA 94720
          "There are no differences but differences of degree 
            between degrees of difference and no difference"