Universe(s)

[azutjw]

Hi all. Please pardon me, I don't post very often, have no wish to offend or be taken as snide.

I have discovered I don't really understand the term 'universe'. I have always thought (I'm well past mid-life, been interested in this stuff since early teens) the term refers to a totality, an infinitude. The whole "expanding universe" thing has always bothered me - seems to me what's actually being spoken of is the 'expansion' of a sector/locality (however large) within the universe, that universe by definition just is. I've studied the (somewhat dumbed-down) writings about a curved universe, and still don't see how it matches.

But lately I have encountered another problem. APOD has referred to a number of galaxies as "island universe(s)". Now I'm really confused. Isn't any galaxy just a conglomeration of stuff much like any other (we think) all within the all-encompassing 'universe'? Putting aside the possible curvature of space/time within our universe, wouldn't any mention of "parallel universe(s)" require an implicit existance of multiple combinations, or sets, of dimensional reality? So as to include multiple editions of space/time, with or without curvature?

Basically, my question is this: what is the accepted definition of the limits of the term 'universe'?

I'd really appreciate hearing discussions from people who deal with these things more often than I.

[bystander]

"Island Universes" was a term applied to galaxies back in the 1920's. It is still used in a poetic sense, but is no longer meant to imply each galaxy is a universe unto itself.

The Universe is meant to imply the sum of everything that exists in the cosmos, including time and space itself.

http://www.astr.ua.edu/goodies/data_res ... axies.text

[Arramon]

Just as no man is an island unto himself..... =)

John Donne....


Pretty much, all things in this Universe are a piece of the whole, or 'clods' of the entire 'mass' of everything we consider the Universe (as in not just what we see, but what we don't see and will never see; the entirety of all things within the material/life forming essence of the Universe).

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Definitions for Universal:
http://ardictionary.com/Universal/1735

1) Universal
Definition: Of or pertaining to the universe; extending to, including, or affecting, the whole number, quantity, or space; unlimited; general; all-reaching; all-pervading; as, universal ruin; universal good; universal benevolence or benefice.

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Merriam-Webster Online Dictionary
http://www.merriam-webster.com/dictiona ... d+universe

Main Entry: island universe
Function: noun
Date: 1867
: a galaxy other than the Milky Way

[emc]

Hi azutjw,

I found your post and wanted to add to the mix… I tend to contemplate the Universe also but from a “common folk” point of view and I tend to get very “bug-eyed” in the process. I can’t seem to get a grip on just how vast our Universe really is, much less that there could be more than one. I would love to have a complete and interactive 3D model!!!

Unless our universe is completely revealed and understood, theories that follow some sort of fact based logic deserve contemplation. There are theories about parallel universes you mentioned that can’t be ruled out as “real” possibility. Imaginative postulates can be the foundation for scientific research and if it is impossible to rule a theory out through repeatable contrary evidence, then it remains a plausible theory. Just like searching for life off planet Earth... certainly another plausible theory... and just like evolution, again, a plausible theory same as creation...!

I noticed the comment about your concern of being offensive or snide (has never been my intention... but other's perception is not in my hands) and I very much share your concern when I post anything into the internet. It is most of the challenge I face in writing these notes that I post in Asterisk to strangers… second is getting my thoughts into intended and comprehensive words so that my thoughts are understandable. Not a simple task for me... but the main reason it is fun to try!

[harry]

G'day from the land of ozzz


Do I need to say something here.

I want to, but! I better not.

[makc]

The whole "expanding universe" thing has always bothered me - seems to me what's actually being spoken of is the 'expansion' of a sector/locality (however large) within the universe

What about something red getting even more red than it was? Do we need to compare it to some standard "red", or can we just measure its light wavelength? Same with something big getting even bigger. While it is true that we cannot tell it's bigger by comparing it directly to something else (because there is nothing else), we can say that some indirect evidence suggests that it behaves same way as it would, were it actually getting bigger... something like that is the logic that applies to "expanding universe" thing.