[This mail came to traveller-request, so I fixed the subject line and
forwarded it to the TML -- James]
The comments regarding space habitats are well considered, but I must
disagree for several reasons.
Earth-like planets will not be common. One per one thousand solar
systems is an optimistic estimate...it may be as low as one per one
million. Planets that can be terraformed will be much more common,
but this is an even larger venture than building a habitat.
Habitats will be expensive to build, but not incredibly so. In two
hundred years, or less, we will have cheap solar and fusion power, and,
more important, intelligent, self-replicating machines. These will
be the key to space industrialization, as it will allow much of the
labor to be done by machines, vastly reducing the expense of any
industrial venture.
The resource base for habitats is enormous. Realistically, you might
be able to put twenty billion people on an Earth-like planet with the
support of high technology. (Personally, I think more than two billion
is a mistake at any tech level.) The asteroid belt alone in our solar
system will be able to support two or three HUNDRED billion, and that
is using my very conservative estimates. Shatter a few of Saturn's
medium-sized moons and the resource base jumps by an order of magnitude.
Why space habitats? First, one must distinguish between a habitat and
a base. A base is designed to be temporary, or at least the crew is not
expected to spend the rest of their lives there. A habitat will be,
literally, a microworld, a self-contained island; the designs suggested
by O'Neill and others make this clear. People do not simply work here;
eventually, these habitats will be permanant communities, similar to
the Pacific islands in "geography" and to the Greek city-states in
socio-political structure (although here Athenian democracy will have
robots for its slave caste).
Second, and more important, evolution. Consider our own solar system,
perhaps two hundred years in the future. There are a few million people
living in L5 space cities in Moon-Earth space, and a few hundred thousand
living in the asteroid belt. Many of them were born in space, some are
even second or third generation spacers. To them, living in habitats is
NORMAL. And they form a large enough seed population--if you assume
high technological support--to start building more colonies, which will
then build even more. (Small gene pool? Hey, guess what becomes Earth's
newest export item!)
Why would the initial population leave Earth? Why would anyone in
their right mind leave England in 1620 for the cold, unfriendly shores
of North America? Or why leave the pleasant towns of New England for
the wilderness of (gasp!) Ohio in the early 1800s? If the technology
of travel and colonization is available, and people live in a society
that is free enough to allow space colonization, it will happen. With
five billion people on Earth, there are enough crazy people to form a
whole bunch of colonies in space. The wilderness, whether it is Ohio
or Ganymede, speaks to something in many of us. Adventure. Fortune.
Freedom. Open skies. The chance to start over.
Ask yourself a simple question. If it was 2190 A.D., and we had the
technology, and you knew that most habitats were pretty safe and pretty
comfortable (a small Pacific island with a medium-sized town on it,
and a HUGE cable TV receiver)...you know you have a 10% chance of getting
rich, an 80% chance of at least doing well, and only a 10% of getting
killed or going broke...wouldn't you be tempted?