Used infinity to predict that another ClamShell

1. Sep 12, 2010

ClamShell

This post is in cosmology (not number theory, eg, Cantor) because
our only (main) exposure to infinity is astronomical.

Folks have used infinity to predict that another ClamShell has or is
or will be typing this message...ballderdash...it would take an
infinity of infinities for this to happen. I accept that The Universe
has always been and was never born and cannot die. Other
explanations just don't seem to make sense. "The Big Bang" is not
even a grain of sand compared to the extent of The Universe.

Mathematically, I suggest, the only operation that makes sense
to finite creatures like us, is the ratio of two infinities. EG, the
infinity of points on a meter stick divided by the infinite extent
of The Universe equals a finite meter...simple as that; Occam
would approve. Also, the infinite amount of matter in The Universe
divided by the infinite volume of The Universe is the finite average
density of The Universe. How many of our precious constants are
really ratios of infinities?...all of them?

2. Sep 13, 2010

zhermes

Re: Infinities

I'm unlear what the point of this post is.

So, in summary: people use infinity to make such statements, and your conclusion is that its ridiculous because it would require infinity?

Occam would surely realize that if the universe was infinite in extent (which we don't think it is), then this ratio would be zero.

Because so many of "our precious constants" are irrational (if not transcendental), they do require limits in their definition, derivation, etc. Also, a 'ratio of infinities' is useless. Limits are useful.

3. Sep 13, 2010

ClamShell

Re: Infinities

Keep going...the root of your misunderstanding of infinity
seems to be that you want the universe to be finite. This
corner of the universe that we sense around us is certainly
finite, but to think that the universe curves back onto itself,
and is satisfied to be finite is sophomoric. You treat infinity
as though it is just a big number. You hear someone say that
the universe is infinitely old, and you probably imagine that
it was "born" at some "time" in the past. But I suggest that
the concept that makes sense is that "infinitely old" simply
means that the universe was never born nor will it ever die.
Infinite in extent simply means that it is everywhere. I also
suggest that you refrain from using "power words" like
"rediculous" and "useless" and instead use a "friendlier word"
like "meaningless". Birth and death are concepts we
give to finite structures...not infinite structures. Cantor
(I think) was the first earth human to point out that there are
an infinity of ponderable infinities...ie, that infinities are
not all the same...imagine that. Any finite number divided
by any infinity is certainly zero. Infinities must have
finite ratios. Anyway, how do you come up with a finite
universe when it is really everywhere?

4. Sep 13, 2010

zhermes

Re: Infinities

I am still unclear as to the purpose of your post / the question you are asking the PF community / the topic you wish to discuss; nor did you address a single aspect of my previous comments in your reply. Be that as it may....

I don't personally care if the universe is finite or not. The general belief however, is that it is finite (spatially)---sure we don't really know, depends on a lot of things, etc etc.

Actually, when I pointed out that you can't just take the 'ratio of infinities,' I was elluding to just the point that 'infinity' is most certainly not a number.

Except for some weird hawking-hartle stuff, if the universe is "infinitely old" that pretty much explicitly means that it wasn't "born" at any time.

While the latter may be true (and is currently indeterminate), the former contradicts all available observations.

Because I am a scientist, and not a sociologist, I'm not concerned with "power" or being "friendly." When I say "useless," oddly enough, I mean it has no use. Similarly, when I say ridiculous, I mean, a synonym for "ballderdash [sic]."

The argument was suggested roughly and geometrically by the greeks (sorry, not sure who); but I think Cantor was the first to rigorously prove it, and establish the idea in number theory. And we should check to make sure mars humans didn't come up with it first.

Not necessarily true. Just like the inverse of your previous example: "infinity of points on a meter stick divided by the infinite extent
of The Universe"

The universe is finite if its geometry is closed. And the argument that 'the universe is everywhere, thus it is infinite' suffers from equivocation, as 'everywhere' is a subset of 'the universe'

5. Sep 14, 2010

ClamShell

Re: Infinities

1) "Infinitely old" implies that it wasn't "born"
(because it has always been)

2) "Infinitely old" implies that it won't "die"
(because it hasn't died)...a fact

3) "Infinite in extent" implies that it is "open"

4) All available observations suggest that it will (can) "die"
(even if it's open or closed?)

5) Therefore it is closed and finite?

I get the feeling that logic postulates open, but this
seems to be contradicted by observation. Sure it would
be nice if observation supported open...but since it seems
not to...I would prefer to think that we have not mastered
the process of observation...and that the universe is open and
infinite in both time and space. I also prefer to think
that there was no "big bang" with its doppler red-shifting
expansion, but only an expected slowing of clocks due to
gravitation as we move from the observer (center) to the
surface of a spherical mass distribution. This is not a
speculation(I have read of) that suggests that stars get
very massive the further they are away from us, but simply
the application of Einstein's GR work. If I start a discussion
called "origin of the Hubble Red-Shift" would you be up-to
taking the doppler view...or would you even consider to
support my proposed GR (static universe) position?

6. Sep 14, 2010

zhermes

Re: Infinities

Observations suggest that the universe is open (in space-time), and thus will never "die" (if by that you mean collapse / end), instead it seems to be expanding indefinitely. The observations aren't 100% however.

Unfortunately, preference is insufficient grounds for a theory. The 'big bang' is very close to observationally confirmed.

Nothing about GR says, suggests, or even implies such a thing. Stars being more massive simply from being further away, completely contradicts physical laws and observations.

Sure

7. Sep 15, 2010

ClamShell

Re: Infinities

Zhermes,
Started that red-shift post I promised...

8. Sep 17, 2010

ClamShell

Re: Infinities

zhermes, my response to your last criticisms is in
"Entropy of the Observer"
Welcome

9. Sep 18, 2010

George Jones

Staff Emeritus
Re: Infinities

I have closed this thread. Physics Forums rules,

in part, state