[extropy-chat] Nuclear terraforming

[Mike15007 at aol.com]

In a message dated 12/16/2005 1:40:23 P.M. Eastern Standard Time,  
wingcat at pacbell.net writes:

As to  Mike's idea of sunshade and oscillators - the problem is
that constructing  things that large wouldn't be as quick as
simply launching a rocket with  existing warheads to Venus.
Although, even the combined power of every  nuclear weapon
currently on Earth probably wouldn't be enough to  significantly
alter Venus's spin anyway.  (Or would  it?)
    It wouldn't. The combined power of every nuke ever  made by Humans is a 
fraction of a percent the energy of the asteroid that killed  the dinosaurs, 
and that rock was "only" several km in diameter max.
    And I didn't say "oscillators." Rather, the immense  solar reflectors at 
Sol-Venus L4, L5, and maybe L2, pivot back and forth in  place, while holding 
their overall position relative to Venus. So the beam of  reflected sunlight 
from each reflector alternately hits or misses Venus. It'll  look odd, like a 
series of small suns lighting-up and going-off periodically,  while remaining 
almost stationary in the sky (Venus does rotate, albeit slowly).  But this is 
the best method I could think of for *simulating* an Earth-like  day-night 
cycle on Venus satisfactorily (I hope - Haven't run every sim yet!)  without 
hitting Venus with something *really big* to alter its spin or putting  lotsa huge 
rockets all around its equator.
    And yes, launching a rocket (or a bunch of them) at  Venus would be 
fairly quick. But how quickly would these get the job we  want done (the important 
thing), and would this screw-up Venus worse, more  than it makes it more 
habitable.



There's also the problem of making the radiator fins out  of
something that can transfer heat well but also stand up to
sulfuric  acid and intense weather.  Glass is the usual container
for sulfuric  acid in labs, but glass is often not the strongest
structural  material.  (And if you just have a glass coating, the
weather could  crack it, letting the acid at what's underneath.)
Remember also that a  lightweight substance would make the whole
mission easier to perform -  easier to ship to Venus.
    Never said it would be easy. There should be  something that'll work. 
Buckytube (with a thin, acid-resistant coating if  necessary) would do for 
structure. Light and as strong as we're going to get  with materials we have now or 
may have available soon.



There's also the problem of radiating heat in space: vacuum  makes
a good insulator.
    Can't do anything about this. But future  spacecraft, with advanced power 
plants (nuclear, fusion, antimatter, etc) will  likely have to have huge 
radiator fins. And with the sunshade blocking all  sunlight to Venus, it should 
cool off *eventually* (Never said this would take  less than a current Human 
lifetime) anyway.



A Venus-diameter sunshade at the Venus-Sun L1 point  would
probably be easier to build - and therefore faster to get  into
place.  I wonder if this faster-ness would offset the  slower
speed of removing Venus's heat.  If the Sun were  completely
blocked off, how long would it take Venus to radiate enough  heat
that the atmospheric temperature would drop to something near
Earth  normal?  (Overlooking, for now, the problems of Venus's
geology and  atmospheric composition and pressure, some of which
problems look like they  might go away by themselves if the
temperature were  reduced.)


Dunno. But if the sunshade is easy to produce and  emplace, the reflectors 
(which are structures not a lot more complicated)  shouldn't be much moreso. The 
radiator fins lowered into the atmosphere will  likely be the biggest 
challenge, admittedly. Hey, terraforming any planet will  not be a project for anyone 
who likes instant gratification easily!
 
Mike
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