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     Intersection: Worldcon '95
    
   
   
  
   
    
     
      53rd World Science Fiction Convention
      
       24 - 28 August 1995, Scottish Exhibition Centre, Glasgow
      
     
    
    
     
      GoHs:
      
       Samuel R. Delany
      
      , Gerry
      Anderson, (fan) Vin¢ Clarke, (filk) Bob Kanefsky
     
     
      
      
       My second Worldcon. The large rooms at the SEC were fine, except for the
      one 'partitioned' into four smaller 'rooms', said partitioning wonderfully
      focusing the sound from each roomlet into the other three, allowing all
      four programme items to be experienced simultaneously.
      
      
       Sadly, Jon Brunner died while attending the Con.
      
      
       
        Programme highlights
       
       
        (Nothing from the first day, since I was flat out with food poisoning --
      not caused by Con food, I hasten to add):
       
       
       
        
        
       
       
        
         Panel: Negative Matter Supported Wormholes
        
        
         
          
           John Cramer
          
          , Geoffrey Landis,
          
           Greg Benford
          
          and
          
           Bob Forward
          
          on their recent joint
      physics paper.
         
        
        
        
        
         - 
          Wormholes can be stabilised by negative mass:
          
           - 
            The Casimir effect is an attractive force between two metal
            plates in a vacuum, because the plates halve the number of virtual
            photon modes. This looks like negative energy, hence negative mass.
           
 
           - 
            Or use negative mass cosmic strings
           
 
          
          
         - 
          A wormhole can have a sphere at each end: 'two spheres of the same
        diameter, each of which encloses the other'
         
 
         - 
          Push a positive charge through a wormhole: the electromagnetic field
        lines are not cut, so the wormhole appears to keep the +ve charge at its
        entry mouth, and have a -ve charge at its exit. This build-up of +ve
        charge repels more charge.
         
 
         - 
          Push a positive mass through a wormhole: the gravitational field
        lines are not cut, so the wormhole appears to keep the +ve mass at its
        entry mouth, and have a -ve mass at its exit. This build-up of +ve mass
        attract more mass.
         
 
        
        
         
         
        
        
         
          Jack Cohen: Redesigning the Human Body for Fun and Fornication
         
         
          
           If it weren't like this, how would it be?
          
         
         
          A typical
          
           Jack Cohen
          
          talk, heavily illustrated
      with slides of cartoons and photographs:
         
         
          - 
           
            Universals and parochials.
           
           If something has evolved on earth
        more than once (flight, eyes, etc) it is a universal, and so aliens may
        also evolve it. If something has evolved only once (the pentadactyl
        limb) it is parochial, and so aliens are unlikely to have evolved it.
        The universal four 'Fs': fur, photosynthesis, flight, mating.
          
 
          - 
           
            We don't understand fertilisation.
           
           Just because we can do
        something, doesn't mean we understand it. We have many new ways of
        making babies (surrogacy, AID, etc.), but we don't understand
        fertilisation. Human reproduction and hormone cycles are very complex.
        If we want to change these, we need to understand how it all works.
        (Human male and female hormones are not 'opposites', they do not 'cancel
        out', they are different.)
          
 
          - 
           
            Rituals.
           
           Reproduction and sexuality are too highly charged
        for rational judgements. Humans cloak them in rituals, like puberty
        rites and wedding ceremonies. Animals also have mating rituals:
        behaviour during sex is very different from most survival behaviour, so
        those instincts need to be overcome.
          
 
          - 
           
            Range of sexual behaviour in animals.
           
           Amazing photographs of
        porcupines, damsel flies, butterflies, rhinoceros ...
          
 
          - 
           
            Varieties of sex in humans.
           
           We are all different from each
        other, by about 10% of our genes. We are not like Model-T Fords with
        just some different gadgets, we are more like hand-crafted cars, each
        individually adjusted to give the 'same' result. Our small external
        difference hide much bigger internal differences. Compared to these
        differences, the difference between female and male are slight: the
        developmental trajectories are very close. Nearly all attempts to alter
        the trajectory result in something nasty.
          
 
          - 
           
            Changing our minds.
           
           If we want to change, more than altering
        our bodies, we need first to alter our minds.
          
 
         
         
          
          
         
         
          
          
           
            The Transactional Interpretation of QM, as recently
            
             
              published
        in Rev.Mod.Phys.
             
            
           
          
          
           Consider a photon emitted by a galaxy a billion years ago, now caught on
      a photographic plate on Earth. The Copenhagen Interpretation has a wave
      front spread over a billion-light-year sphere instantly collapsing to a
      point. Everett's Many-Worlds Interpretation has many parallel universes,
      some where the photon hits different plates at different times, some where
      it is never absorbed. The Transactional Interpretation considers both the
      retarded and advanced waves, constructively interfering with each other
      along the path between the emitter and absorber.
          
          
           (Heisenberg's wave equation has two solutions, psi, and psi-star. Psi,
      the retarded wave, which travels forwards in time, is standard solution.
      Psi-star, the advanced wave, which travels backwards in time, is usually
      discarded as non-physical.)
          
          
           CI requires swallowing instant collapse of wavefunctions, hence faster
      than light travel; Many Worlds requires swallowing prodigious replication;
      TI requires swallowing time travel.
          
          
           CI, Many-Worlds, and TI are all
           
            interpretations
           
           of the
           
            same
           
           mathematics. So they have no different predictions or observable
      consequences. (The Transactional Interpretation
           
            might
           
           require an
      open universe to explain the arrow of time, to cater for 'non-observed'
      events of particles that are never absorbed.) Weinberg's attempt to add a
      small non-linear component (for which there is no evidence) would
      distinguish them: Everett can use it to communicate between parallel
      worlds; TI can use it to communicate backwards in time.
          
          
           Ptolomey had the Earth at the centre of the Universe, and everything
      rotating around it. The Copenhagen Interpretation has the observer at the
      centre of the Universe, and everything collapsing around it: "The
      Collapsor of Wavefunctions".
          
          
           
            Greg
          Bear