From: Caio Tiago Oliveira <caiot1@...>
Date: 2005-02-07T09:49:07+09:00
Subject: Re: [OT] Physics of black holes (Was: RubyConf '05)

Tim Bates, 6/2/2005 18:52:
> Josef 'Jupp' Schugt wrote:
> 
>> (...) The relative speed of galaxies for example is known to exceed
>> the speed of light.
> 
> 
> No, it's not. You've forgotten your elementary relativity. If you
> have two galaxies on opposite sides of the universe (call them A and
> B) with an observer in between (called O) then from O's frame of
> reference the sum of the speeds of A and B might exceed c (the speed
> of light), although neither galaxy's individual speed can exceed c,
> BUT from A's frame of reference B's speed does not exceed c and vice
> versa.
> 
> If this sounds bizarre and impossible to you, you haven't studied
> physics.


I studied physics and I agreed with Josef.
The universe is in a expansion (an acelerated one). The universe wich is 
visible to us is smaller than the whole universe, just because the 
galaxies outside the visible universe are moving away from us faster 
than the light they emit, so we never see this light.
The faster the universe is expanding, less we can see, the near the 
galaxies move away faster than the light.