andrel wrote:
> On 30-3-2010 18:11, Darren New wrote:
>> andrel wrote:
>>>> How about the fact that the stars of the universe are all 
>>>> red-shifted the farther they get from *us*?  Or the fact that we 
>>>> seem to be the only creatures in the entire *universe* that 
>>>> broadcast radio signals?
>>>
>>> For the latter see the Drake equation.
>>
>> I'm familiar with it. What about it?
> 
> All we know that there are no radio signals broadcasted from a place 
> exactly the right time ago to be just reaching us now, send towards us, 
> and in a format that we recognize. Which is quite a long way away from a 
> conclusion that no signals are send at all.

Yes. Hence the "seems to". Anyway, you understand my point even if you 
disagree. :-)

>> Yep. That doesn't mean things are moving away from us. We can't 
>> measure whether they're moving away from us. All we can measure is the 
>> red shift. The assumption is that the red shift is caused by relative 
>> motion, and not the geometry of the universe.
> 
> I don't understand that last sentence, but that may be my physics 
> background.


We assume that the distant galaxies are red-shifted *because* they are 
moving away from us. We don't assume that the Milky Way has the lowest speed 
of light in the universe, or that time runs slower the farther you get from 
humanity, or that the gravitational constant is slowly increasing the 
farther you get from humanity.  *If* you assume that all other places in the 
universe will see the same thing when they look around, *then* all the 
galaxies must be moving away from each other.  *If* you assume we're in a 
unique and privileged place in the universe, there are all kinds of things 
that could be causing it.


-- 
Darren New, San Diego CA, USA (PST)
   Yes, we're traveling together,
   but to different destinations.

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