From: sylvia@not.at.this.address   
      
   On 7/10/2017 3:26 AM, Luigi Fortunati wrote:   
   > As it goes away, any object on Earth appears to us ever smaller, and as   
   > it approaches it seems bigger.   
   >   
   > Is this inverse proportionality between the distance of a known object   
   > and its apparent size (theoretically) allow in the future to   
   > immediately know a distance simply by measuring one its apparent size   
   > without having to synchronize the clocks and without having to wait for   
   > a return signal?   
   >   
      
   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.   
      
   Sylvia.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)