Infinite Universe, Infinite Mass, Infinite Gravitational Force

[The Don]

From H'thethethehtehtethehtehthethehteht in another thread

Right, but that just implies that if the universe is infinite, it allways has been, even during the big bang. Hard to imagine but im not sure if it's impossible per se. I'm underinformed conerning the big bang.
Two alternatives for an infinite universe:

Either it originated from a single point (the big bang) in which case, the big bang had to happen an infinite amount of time ago

OR

It "spanged" into existence as a universe of infinte size

If it's the second, then you're right, the gravitational effects of the outlying regions haven't reached us yet. If it's the former then the gravitational effects must have reached us by now.

Clearly the first is not the case, so the only alternative for an infinite universe is the second. Which may be the case but there's no evidence for it

[H'ethetheth]

Originally posted by The Don
From H'thethethehtehtethehtehthethehteht in another thread


Two alternatives for an infinite universe:

Either it originated from a single point (the big bang) in which case, the big bang had to happen an infinite amount of time ago

OR

It "spanged" into existence as a universe of infinte size

If it's the second, then you're right, the gravitational effects of the outlying regions haven't reached us yet. If it's the former then the gravitational effects must have reached us by now.

Clearly the first is not the case, so the only alternative for an infinite universe is the second. Which may be the case but there's no evidence for it

Why is there no evidence for the second scenario? I think the only thing we know about just after the big bang is that the density and temperature of the universe were very high. This tells us nothing about the amount af matter or the amount of space at the big bang.
As I said though, I'm more than willing to learn the state ot scientific research on this matter. If I'm completely wrong I will - unlike lifegazer - concede if sufficient good arguments are presented.

By the way, maybe this thread should be moved to the science, mathematics etc forum.

[lifegazer]

Originally posted by The Don
Two alternatives for an infinite universe:

Either it originated from a single point (the big bang) in which case, the big bang had to happen an infinite amount of time ago

You talk about the universe with a fixed origin. The time between then and now cannot infinite. Infinity has no origin or end.

OR

It "spanged" into existence as a universe of infinte size

From nothing, or from the void of infinite space?

[The Don]

Originally posted by H'ethetheth
Why is there no evidence for the second scenario? I think the only thing we know about just after the big bang is that the density and temperature of the universe were very high. This tells us nothing about the amount af matter or the amount of space at the big bang.
As I said though, I'm more than willing to learn the state ot scientific research on this matter. If I'm completely wrong I will - unlike lifegazer - concede if sufficient good arguments are presented.

By the way, maybe this thread should be moved to the science, mathematics etc forum.

I agree it should be moved.....

The current thought is that the big bang was from a point source (on the grounds that the age of the universe is calculated by spacial regression). Here's a couple of easy to digest articles (forgive me if I insult your knowledge, I, a rank amateur could be talking down to an astophysics professor):

http://www.umich.edu/~gs265/bigbang.htm

http://www.homestead.com/philofreligion/files/BigBangCosmologyPrimer.htm

[The Don]

Originally posted by lifegazer
You talk about the universe with a fixed origin. The time between then and now cannot infinite. Infinity has no origin or end.
Errrrrr. you don't *do* reading comprehension do you ? The fact that the universe is NOT infinitely old indicates that an infinite universe cannot have originated from a point source

Originally posted by lifegazer
From nothing, or from the void of infinite space?

There's nothing outside the universe, even void is part of the universe. As there is no evidence for the universe suddenly appearing at an infinite size (see the second of the above links) then we can be sure that current thinking precludes an infinite universe.

Like I've said a number of times, the universe is finite but unbound. It's expanding into "tommorrow"

[H'ethetheth]

Originally posted by The Don
I agree it should be moved.....

The current thought is that the big bang was from a point source (on the grounds that the age of the universe is calculated by spacial regression). Here's a couple of easy to digest articles (forgive me if I insult your knowledge, I, a rank amateur could be talking down to an astophysics professor):

http://www.umich.edu/~gs265/bigbang.htm

http://www.homestead.com/philofreligion/files/BigBangCosmologyPrimer.htm

I haven't read the articles yet, but I'd like to point you to the fact that my avatar displays myself, I'm a 25 year old student and an amateur as much as you. My science is aerospace engineering a.k.a rocket science so I have no authority on fundamental physics, you may bash me as you see fit. :D

[H'ethetheth]

And noe I have read the articles, but the first one just says it couldn't have been infinite, and the second says it was infinitely compressed. Neither of these statements address what I want to know. :(
But I'm contemplating the following...

- It could be infinitely compressed and infinitely small, meaning finite mass and energy in a finite volume.
- It could be infinitely compressed and have finite dimensions, which would mean infinite mass and energy in a finite space which could never become infinite in size before infinity is over.
- It could be infinitely compressed yet infinite in size, which would mean infinite mass and energy in an infinite volume. This sounds like ludicrous nonsense but I'm not sure if it actually is. So I'd like some help here.

[The Don]

Searching around a bit more I found this graph

http://hyperphysics.phy-astr.gsu.edu/hbase/astro/imgast/inflat2.gif

from here: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/planck.html#c2

[H'ethetheth]

Hmmm, apparently it is ludicrous nonsense to think that the universe started infinitely large but very much smaller.
But still, I want to know why exactly. I can't see an immediate contradiction that is very much stranger than the big bang from some finite very small universe. I'm probably underinformed.
It's time to find some books on the subject. :book:

[The Don]

A person far more qualified to answer your questions than I am is Phil, the bad astronomer

http://www.badastronomy.com/

[H'ethetheth]

Originally posted by The Don
A person far more qualified to answer your questions than I am is Phil, the bad astronomer

http://www.badastronomy.com/

Yeah I know his site, it's amusing and thorough. I got to JREF through there. And I got there looking for information on that hilarious Fox moon hoax 'documentary'. :hit:
Maybe I should send him a PM.

[c4ts]

Yeah, Phil's had a lot of good publicity lately. I think he's scheduled to speak at this year's TAM in Vegas.

[H'ethetheth]

An interesting FAQ at UCLA:

http://www.astro.ucla.edu/~wright/cosmology_faq.html#RB

It's what I thought, they're not sure yet. Not in Los Angeles anyway. :D