Invisible wrote:
> Does anybody know of a list anywhere that gives examples of really large 
> numbers? 

I don't know about "really big", but here's a start for moderately large.

http://www.kokogiak.com/megapenny/

-- 
Darren New / San Diego, CA, USA (PST)
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On 29-Jul-08 22:09, Darren New wrote:
> andrel wrote:
>> No you gave a website that discusses the 'observable universe' which 
>> is a totally different beast than the size of the universe at some 
>> moment in time.
> 
> Two fallacies: (1) "observable universe" technically is the same as 
> "universe".  

why? For many people God is part of this universe, yet not part of the 
observable universe. (I know you did not mean that).

> (2) "moment in time" is a meaningless term, even for things 
> fairly close together, let alone separated in a spacelike way.

yes. I am aware of that. Here informally meant to mean every point in 
space time that has the same value for the time component. So rather 
undefined indeed.

> In other words, define "universe" first. This gets you into Clinton 
> areas, of trying to define what "is" is.

Hmm, I did not know he once tried to define the universe. I know that 
his definition of sex was peculiar, so I assume you refer to that.

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andrel wrote:
> why? For many people God is part of this universe, yet not part of the 
> observable universe. (I know you did not mean that).

Because "universe" means "everything there is". Define "is" in a way 
that includes things that do not and never will have any chance of 
affecting any sort of causality in your observations.

>> (2) "moment in time" is a meaningless term, even for things fairly 
>> close together, let alone separated in a spacelike way.
> 
> yes. I am aware of that. Here informally meant to mean every point in 
> space time that has the same value for the time component. So rather 
> undefined indeed.

It's the informality that kills you, tho. There's no such thing as "the 
same time component". The same point in spacetime has many values for 
the time component. You can have two things that happen "at the same 
time", and I experience A happening before B, and you experience B 
happening before A, and Andrew experiences them both happening at the 
same time. There isn't any universal clock you can use to determine the 
"time component" for a place in space, any more than there's any 
universal clock you can use to determine the Y component of a parabola.

>> In other words, define "universe" first. This gets you into Clinton 
>> areas, of trying to define what "is" is.
> 
> Hmm, I did not know he once tried to define the universe. I know that 
> his definition of sex was peculiar, so I assume you refer to that.

No, I was referring to his arguing over what "is" is. Does something 
completely outside your causality exist? Is there an actual definition 
you could come up with that would make "the universe" bigger than "the 
observable universe"?

-- 
Darren New / San Diego, CA, USA (PST)
  Helpful housekeeping hints:
   Check your feather pillows for holes
    before putting them in the washing machine.

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andrel <a_l### [at] hotmailcom> wrote:
> What I do know is that I studied special and general relativity 
> and some cosmology when I was at the university and that your claim that 
> the real size of the universe may be 'staggering larger' than the 
> observable universe does not seem to fit what I remember.

  You might find this article interesting:

http://www.sciam.com/article.cfm?id=misconceptions-about-the-2005-03

  A quote:

"Notice that, according to Hubble's law, the universe does not expand
at a single speed. Some galaxies recede from us at 1,000 kilometers
per second, others (those twice as distant) at 2,000 km/s, and so
on. In fact, Hubble's law predicts that galaxies beyond a certain
distance, known as the Hubble distance, recede faster than the speed
of light. For the measured value of the Hubble constant, this distance
is about 14 billion light-years."

  And btw, I didn't say the universe *is* staggeringly larger than the
observable part of it (observable by us, that is). What I said is that
it's perfectly *possible* for it to be enormously larger. We simply have
no physical means of knowing. However, AFAIK, current consensus is that
it's probable that the size of the universe is significantly larger than
the observable part, because that's one good explanation of some observed
phenomena related to the big bang theory.

-- 
                                                          - Warp

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On 29-Jul-08 23:35, Warp wrote:
> andrel <a_l### [at] hotmailcom> wrote:
>> What I do know is that I studied special and general relativity 
>> and some cosmology when I was at the university and that your claim that 
>> the real size of the universe may be 'staggering larger' than the 
>> observable universe does not seem to fit what I remember.
> 
>   You might find this article interesting:
> 
> http://www.sciam.com/article.cfm?id=misconceptions-about-the-2005-03
> 
>   A quote:
> 
> "Notice that, according to Hubble's law, the universe does not expand
> at a single speed. Some galaxies recede from us at 1,000 kilometers
> per second, others (those twice as distant) at 2,000 km/s, and so
> on. In fact, Hubble's law predicts that galaxies beyond a certain
> distance, known as the Hubble distance, recede faster than the speed
> of light. For the measured value of the Hubble constant, this distance
> is about 14 billion light-years."

That is what I said also. So given the time of day, I skip that one for 
tonight.

>   And btw, I didn't say the universe *is* staggeringly larger than the
> observable part of it (observable by us, that is). What I said is that
> it's perfectly *possible* for it to be enormously larger. We simply have
> no physical means of knowing. However, AFAIK, current consensus is that
> it's probable that the size of the universe is significantly larger than
> the observable part, because that's one good explanation of some observed
> phenomena related to the big bang theory.

AFAIK that is not the consensus. I.e. if significant means a couple of 
times. If it means a P<.05 that is probably true.

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On 29-Jul-08 23:26, Darren New wrote:
> andrel wrote:
>> why? For many people God is part of this universe, yet not part of the 
>> observable universe. (I know you did not mean that).
> 
> Because "universe" means "everything there is". Define "is" in a way 
> that includes things that do not and never will have any chance of 
> affecting any sort of causality in your observations.

There may be things that you know existed or must have existed once but 
now are outside of your observation forever.

>>> (2) "moment in time" is a meaningless term, even for things fairly 
>>> close together, let alone separated in a spacelike way.
>>
>> yes. I am aware of that. Here informally meant to mean every point in 
>> space time that has the same value for the time component. So rather 
>> undefined indeed.
> 
> It's the informality that kills you, tho. 

I think I acknowledged that already.

> There's no such thing as "the 
> same time component". The same point in spacetime has many values for 
> the time component. You can have two things that happen "at the same 
> time", and I experience A happening before B, and you experience B 
> happening before A, and Andrew experiences them both happening at the 
> same time. There isn't any universal clock you can use to determine the 
> "time component" for a place in space, any more than there's any 
> universal clock you can use to determine the Y component of a parabola.
> 
>>> In other words, define "universe" first. This gets you into Clinton 
>>> areas, of trying to define what "is" is.
>>
>> Hmm, I did not know he once tried to define the universe. I know that 
>> his definition of sex was peculiar, so I assume you refer to that.
> 
> No, I was referring to his arguing over what "is" is. 

Ok, never heard that one before.

> Does something 
> completely outside your causality exist? Is there an actual definition 
> you could come up with that would make "the universe" bigger than "the 
> observable universe"?

As said, I think you can.

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andrel <a_l### [at] hotmailcom> wrote:
> AFAIK that is not the consensus. I.e. if significant means a couple of 
> times. If it means a P<.05 that is probably true.

  If, according to you, the universe is expanding at velocity c (what does
that even mean?), and given that current measurements seem to indicate that
the expansion is actually accelerating, how do you explain this?

  Two questions:

1) What do you mean by "expanding at a velocity of at most c"? Where is
   this c velocity, and compared to what?

2) Since you have clearly agreed that the expansion of the universe is
   not bound to speed limitations between objects, then what is the
   phenomenon which limits the expansion of the universe to c?

  In other words, you seem to say "yes, it is possible for two points in
the universe to recede faster than c from each other, but that's not
happening anywhere in the universe". Why not?

-- 
                                                          - Warp

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andrel wrote:
> There may be things that you know existed or must have existed once but 
> now are outside of your observation forever.

I'm pretty sure those count as part of the "observable universe". They 
have a causal influence on your observations.

>> Does something completely outside your causality exist? Is there an 
>> actual definition you could come up with that would make "the 
>> universe" bigger than "the observable universe"?
> 
> As said, I think you can.

I'd like to hear it. :-)

-- 
Darren New / San Diego, CA, USA (PST)
  Helpful housekeeping hints:
   Check your feather pillows for holes
    before putting them in the washing machine.

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Warp wrote:
> on. In fact, Hubble's law predicts that galaxies beyond a certain
> distance, known as the Hubble distance, recede faster than the speed
> of light. For the measured value of the Hubble constant, this distance
> is about 14 billion light-years."

Here's an interesting question, tho: Consider the galaxies that are 
receding at (1-epsilon)*c from us. Galaxies[1] that will cross the 
boundary from timelike to spacelike distances in (say) the next year.

It can't accelerate faster than light, right? Is it going to go slower 
and slower, like an object falling into a black hole will, from our 
point of view?

Hmmm, thinking on it, if the expansion is caused by expanding space, 
maybe time doesn't seem to slow down? Do you not get relativistic time 
dilation from expanding space? If not, why do photons red-shift? If so, 
why would we see any galaxy ever "cross" the speed of light as it recedes?

I did see an interesting speculation once that the 3-degree background 
radiation was actually all the galaxies piled up against the lightspeed 
barrier, but I have no idea how much sense that makes.

[1] Or planets, or specs of dust, or whatever's small enough for you to 
accept this happens.
-- 
Darren New / San Diego, CA, USA (PST)
  Helpful housekeeping hints:
   Check your feather pillows for holes
    before putting them in the washing machine.

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Darren New wrote:

> I don't know about "really big", but here's a start for moderately large.
> 
> http://www.kokogiak.com/megapenny/

Ooo... interesting.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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