On Saturday, February 17, 2018 at 1:30:08 AM UTC-5, johnny1...@gmail.com wrote:   
   > Hypothetically, imagine a starship comes across a human-inhabited,   
   Earth-like world, on which the former cities and centers of civilization have   
   been heavily nuked.  Assume it's been at least decades since the bombs fell.   
   >    
   > My question is, what if any signs would differentiate the results of a big,   
   world-wide nuclear exchange by locals on the planet, Cold War style, from a   
   space-based bombardment carried out by outside forces?  Would there be   
   anything that would strongly    
   indicate one scenario over the other?   
      
   The fallout areas would contain ions of nuclear material that did not fission   
   and also daughter compounds of materials that did.  So you could, for example,   
   prove that the nukes that hit cities A and B had 41.2% U235 and a plutonium   
   239 trigger, City C    
   had 48.4% U235 and City D got nuked by a plutonium only tactical device. You   
   can further finger-print the plutonium source by the amount of pu240 and other   
   isotopes mixed in with the 239.  The nuclear exchange will probably destroy   
   some weapons so City C    
   probably has some non-exploded ordnance with 41.2% U235 a facility that   
   contained(s) 41.2% U235, and a processing plant that was capable of separating   
   the isotopes.  You can also look at the blast size and irradiated components   
   from the vehicle(bomb)that    
   held the physics package. If all of that matches then you can make a strong   
   case for city C firing the nukes at A and B in an exchange.     
      
   If there are no nuclear reactors, no nuclear waste storage containers, no   
   remnants of nuclear leaks, and no uranium mines then it is unlikely that the   
   natives had nukes.  Since these are humans on an earth-like planet did they   
   travel there?  They could    
   have transported nukes with them when they arrived.     
      
   The space launched weapons would need re-entry heat shields and probably   
   rockets or some way to aim.  ICBMs also need reentry devices but they can be   
   much smaller.  Remnants could still be found.  A device designed to plunge   
   into an atmosphere vertically    
   would look a lot different from heat shields designed to slow down a vehicle.    
   If the vehicle did not slow down the heat shield would still be in front of   
   the physics package when the nuclear explosion occurs. That would change the   
   fallout pattern for    
   fission materials and you would find a separate fallout pattern for neutron   
   irradiated elements that were components of the heat shield.     
      
   If an interplanetary bombardment had any misses they could still be floating   
   around the system.  If any detonated in space there would be some fallout on   
   asteroids and moons.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)