|
![](/i/fill.gif) |
Warp wrote:
> Orchid XP v8 <voi### [at] dev null> wrote:
>> On 25/01/2011 08:11 PM, Warp wrote:
>
>>> My take: If there is life in the Universe (which happens to be the case),
>>> some of that life must have been the first one to form. Well, we might just
>>> be that first, don't you think?
>
>> My understanding of general relativity is limited, but I was under the
>> impression that "first" is not a meaningful concept at relativistic
>> velocities.
>
> That would be paradoxical.
>
> Assume that intelligent life evolves in planet A, and it starts sending
> radio signals to outer space. These radio signals eventually reach planet B.
>
> Some time later life evolves in planet B to a point where they can receive
> these signals from A. Clearly, intelligent life evolved in A first, and in
> B after that.
If A and B are separated by space-like distances, neither is first. Here
you're postulating that A and B (where A and B are the evolution of initial
radio-emitting life) are separatd by time-like distance.
As you say, if one is in the past light-cone of the other, there's a first
and a second. It only gets ambiguous where neither of the two 4D events are
in the direct past light-cone of the other.
--
Darren New, San Diego CA, USA (PST)
"How did he die?" "He got shot in the hand."
"That was fatal?"
"He was holding a live grenade at the time."
Post a reply to this message
|
![](/i/fill.gif) |