Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>>   Galaxies do not expand because their gravity keeps them in shape. In
>>> other words, gravity inside (and near) galaxies is strong enough to
>>> "resist" the expansion. Consequently nothing inside galaxies expands.
> 
>> Hmmmm.... I'll take this idea with a grain of salt. :-)
> 
>   Why?

Because if space expands (say) 10%, and matter doesn't, then there's 
something very funky going on. It would be like relativity saying 
"clocks slow down, but not actual processes".

It doesn't seem logical to me that space expands 10% outside the galaxy 
but not inside the galaxy. If there's a reason for "mass" to keep nearby 
space from expanding at all, I don't know what it would be.

Now, if space expanded and gravity pulled everything back together, that 
makes sense. But that still doesn't answer the question of whether (for 
example) a brick floating in intergalactic space would be 10% bigger if 
given enough time.

>>>   Another slightly difficult thing to grasp is that a constant expansion
>>> of the universe actually means that galaxies recede from us at an exponential
>>> rate. At each certain unit of time space distances double, which means that
>>> the distance between two galaxies grows exponentially with time. 
> 
>> Yet, funny enough, the number of galaxies we see in an area is constant 
>> for a given volume, or close to it. This implies that perhaps the 
>> galaxies aren't receding at all, and space isn't growing at all.
> 
>   Why? If the expansion is even throughout the universe and galaxies where
> distributed about equally to begin with, they will be distributed equally
> at all times regardless of the expansion.

The distance between a galaxy 10 units away and one 20 units away should 
be less than the distance between a galaxy 20 units and 30 units away, 
because there will be more space added between us and 30 units than us 
and 20 units. I think.

Like you said, more distant galaxies are moving away at an exponentially 
faster rate. It was something to do with this, altho I might have 
misremembered exactly the measurement. (Altho I remember it was a pretty 
simple measurement.)

Hmmm... Maybe it was something like we should see more galaxies with a 
5% redshift than a 10% redshift, or something.

>> I saw an interesting paper that postulated that what we observe would 
>> also be correct if further galaxies simply had a time axis pointing away 
>> from us.
> 
>   Are we the center of the universe?-)

Everyone is. :-)  I thought maybe the reason SETI fails is that we 
really *are* the first intelligent race because we're at a place where 
time is running fastest. :-)

>> It explains why we see a constant number of galaxies in 
>> a given space
> 
>   I don't understand why an expanding universe couldn't have a constant
> number of galaxies in a given space.

Hmmm... Maybe I'm misremembering. In any case, the paper claimed there 
was an anomaly along those lines, in terms of "if space was expanding, 
we'd see a distribution like ... but we don't". I wish I could find the 
paper again. I tried searching a couple times and came up with nothing.

-- 
   Darren New / San Diego, CA, USA (PST)
     It's not feature creep if you put it
     at the end and adjust the release date.

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