Re: Terraforming NOT! [was Re: SF book recommendations wanted...]

From: Robert J. Bradbury (
Date: Fri Jun 02 2000 - 08:02:25 MDT

On Fri, 2 Jun 2000, Martin Ling wrote:

> Hmm... perhaps we need to be moving greenhouse gases from Venus to Mars,
> terraforming both at once?
> Great big mass driver firing dry ice from one to the other?

If you want to optimize the materials usage, you want to split
up the CO2, send the O2 to Mercury where you can merge it with
the excess Fe from the planet's core forming Fe2O3, which is not
a terrible structural material (not as good as Diamond or Sapphire,
but the only other things iron is good for is core memories and
radiation shields). The fundamental problem is that oxygen is
relatively abundant and so you need to distribute it among the
metals because metal oxides are stronger than the metals themselves.
Since carbon is more abundant than oxygen, you will always have
CO2 available if you need it for a greenhouse gas, though you might
have to ship in comets from the outer solar system. On a minimum
mass basis, you might be better off using chloro/flouro-carbons
for your greenhouse gas, leaving more C(diamond) & Metal-On available
for other construction activities.

We need to work out whether the best use of the available Cl/F
is for habitat greenhouse gases. One nice thing, is that their
mass is higher than CO2, so you can use them more effectively
on smaller planetoids without worrying about their escaping.

I'm still puzzled over what to do with the relative abundance of
magnesium. Not a great structural material as a metal or MgO.
Perhaps a propellant in the ion drives, since you have to eject
*something*. The nitrogen, sodium & potassium don't appear to be
of much use either.

There is an entire field of solar-system-forming that is fairly
unexplored. It is probably a universal problem because the
generally believed theories of solar system formation dictate
that the heavy elements form planets close to the sun while the
lighter elements (including much of the C in CH4 & CO2) end
up in the outer regions of the solar system, which would not
seem to be where you ultimately want it.


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