From: fortunati.luigi@gmail.com   
      
   Sylvia Else domenica 08/10/2017 alle ore 18:53:19 ha scritto:   
   > To infer its distance, you would have to know its actual size. If you   
   > know that, then you can determine how far away it was at the time when   
   > the light from it was emitted.   
   >   
   > However, even without knowing its actual size, and thereby its actual   
   > distance, you can still determine its arrival time (if it's coming   
   > directly towards you) by considering the rate at which its apparent size=   
      
   > changes as a proportion of its apparent size.   
      
   Thanks, clear and comprehensive answer.   
      
   --   
   Luigi Fortunati   
      
      
   -Nonostante tutto il mio impegno non riesco a imporre alla mia ragione   
   l'accettazione dell'irrazionale.   
   -Despite all my commitment I can not impose on my reason the acceptance   
   of the irrational.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)