Planetside vs. space-based WAS Maintaining very small ecosystems

ecosystems

[snikt]
> Well, this is where the vagueness of future technology comes into play,
> but mechanical breakdown, either accidental or intentional, seems much
> more catastrophic if you need it to breathe. Personally, I'd just feel a
> lot safer in general if I'm in an environment that can sustain my life
> without needing to be completely sealed off via plastic or metal from a
> hostile external environment. Yes, I recognize that a big enough rock or
> chemical reaction could destroy an entire planet's atmosphere, but the
> scale of the destruction required for such a catastrophic event is a few
> orders of magnitude greater than what's needed to destroy some sort of
> biodome. Maybe I'm just old-fashioned?
>

I myself have felt that way sometimes when imagining living off-Earth. But
that is just an emotional, instinctive reaction; perhaps the result of so
many sci-fi movies showing depressurization and people blowing out in
space...

However, when you do the math, you can demonstrate, for example, that the
probability of getting killed by an asteroid is the same of dying in a plane
crash. How that is possible? Asteroid hits are extremely rare, *but* they
have the potential to kill *billions* of people.

As for mechanical breakdown in a habitat... Punctures, depressurization,
that sort of thing... Considering natural ones, the only possibility that
comes to my mind is meteoroid hit, and the probability of a meteoroid big
enough to puncture a radiation shield ten meters thick is *very* low. And,
even if that happens, the atmosphere of the habitat would not be lost
instantly, killing everyone. In fact, depending on the size of the hole and
the atmospheric volume of the habitat, it could take weeks for people start
to getting dizzy due to low pressure - more than enough time to repair the
habitat.

Breakdowns of artificial origin maybe more probable. Mad terrorists willing
to blow a hole in the habitat, or war. However, even though that happens,
causing the loss of a great part of the population of the habitat, that loss
would be comparable to that suffered by a city bombarded from the air or
something; in other words, catastrophes affecting a habitat are of urban
scale, and not of planetary scale. A planetary-scale population would occupy
thousands of habitats and, considering this huge number of habitats and the
exceedingly bad luck needed to destroy all of them, it seems that this
population would be safer scattered through all those myriads habitats than
concentrated in a planetary surface. In fact, if we have a space-faring
civilization, planetary surfaces are not that safe from artificial
breakdowns, either: anyone could hit a planet with an asteroid...

[snikt]
> Interesting analogy. I wonder if people remain clustered in cities now
> because that's where they were first, then? Since it's not that difficult
> to get from any one point in the world to anywhere else any more thanks to
> airplanes. And I can tell you, flying out of Logan Airport in Boston is a
> pain in the patooshki. And it's actually a lot cheaper to live in the
> Midwest of the United States than either coast these days, so can cost
> still be considered the primary factor? If this is the case, I wonder if
> Lunar or Mars-based biodomes will be more or less popular than permanent
> space-based habitats? And will it all come down to which became the
> standard mode of settlement first?
>

Your hypothesis about most people still living nearby oceans and navigable
waterways being an inertial phenomenon is interesting and worth
investigation, certainly, but personally I still think that it does not fit
well the economic flux. Aircraft are economically viable for transportation
of people and goods that are light and extremely valuable (e.g.,
electronics). However, when your goods have to be transported by the
thousands of tons, then you *have* to use ships. I think that you will never
see oil, grains, ores and other things being air transported. So, there is
still an influence - and a powerful one - keeping the bulk of economic
activity - and therefore people - close to the oceans.

You could have *real* space*ships* - cargo ships able to hold hundreds of
thousands of tons of payload, or liners transporting thousands of
passengers - going from a space habitat to the other. On the other hand,
unless antigravity is invented, or huge space elevators are constructed, you
could not do the same thing depart from Earth surface. (Well, actually
perhaps you *could* do that - using nukes and destroying everything in a
radius of many kilometers. ;-)

[snikt]
> Cheers,

Cheers,

> --Justin
[snikt]

--Lucio