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napkin111
12-16-2002, 12:02 PM
I don't know why, but I just started thinking, is there an end to the universe? I think there is not and if there was I would probably kill myself (well, maybe not). I mean, are you going to hit a big boarded off wall that says "under construction" on it?
What do you guys think?

Here is an interesting read: http://www.time.com/time/covers/1101010625/story.html

I changed the subject from "univers" to "universe". I was totally sick of looking totally illiterate.

[re-edit]Ack! didn't work on main message board...[/re-edit]

//napKIN

Clyde
12-16-2002, 12:06 PM
Current opinion within the field of cosmology seems to favour 'no' as an answer to your question, but there is an end to everything bar heat within the universe.

Edit: rereading your question, i think i perhaps misunderstood it, the answer is still the same, as far i'm aware its still no, you don't hit a wall, you end up back where you started. But i may well be mistaken since the last i heard the universe was deemed flat rather than curved.

damonbrinkley
12-16-2002, 12:50 PM
Man, astronomy just amazes me.

adrianxw
12-16-2002, 01:43 PM
Clyde: What do you think about "Membrane Theory", or more colloquially "M" theory? This is the one that supposedly takes us back through the big bang into the membrane multiverse that is "outside" our universe.

Fascinating ideas I thought.

salvelinus
12-16-2002, 02:25 PM
Yes. Jim Morrison sang about it. You might not want to tell your mother, though.
:eek:

Imperito
12-16-2002, 02:36 PM
Yes, there is an end. It's an 'e'.

Clyde
12-16-2002, 05:06 PM
"Clyde: What do you think about "Membrane Theory", or more colloquially "M" theory? This is the one that supposedly takes us back through the big bang into the membrane multiverse that is "outside" our universe."

It is certainly very interesting, Stephen Hawking discusses it a bit in "Universe in a Nutshell", it certainly sounds very interesting, i do not have the expertise to pass any kind of judgement on how plausible or unplausible it may be, as far as I know it is currently an untestable hypothesis, though that may change in the future.

Shadow12345
12-16-2002, 05:20 PM
I didn't read the article. It's been theorized the universe is infinitely expanding from the big bang. There is supposedly no 'end', that seems to make sense. I don't think that is a particularly mind boggling question. A really mind boggling question is what in the hell was 'there' before the big bang took place :)

I wrote a really long paper trying to explain that the universe can be explained, but not ever completely explained by humans. That we can in fact observe hierarchies of complexity that probably extend infinitely into higher and higher 'systems'. I compared humans and dogs, saying that although humans and dogs coexist within the same physical area (Earth) we live in totally different realities, that dogs don't understand any of the things around them. I then basically tried to predict the next step in the hierarchy saying humans are the proverbial dogs and that we lack understanding of the universe in much the same way dogs lack the technical understanding of how cars work (for example) : it can fully be explained, but you can never explain it to a dog.

EDIT: Now that I re-read this I really sound like I'm full of ****, but I hope you all at least consider and try to understand what I'm trying to say

Sebastiani
12-16-2002, 07:08 PM
I think that "the end" is a subjective thought. In ancient times some thought the earth was flat. With that thought in mind, moving in a straight line would indeed be endless. Perhaps the same holds true for the end of the universe.

Shadow12345
12-16-2002, 07:37 PM
Interesting

I think that's a good way to think of it

I wish I had thought of it that way

lightatdawn
12-16-2002, 07:52 PM
>>I think that's a good way to think of it

Try reading the article. Then you wont have to guess. ;)

>>what in the hell was 'there' before the big bang took place

Possibly nothing.


Thats a rather good article, napkin; Thanks for sharing it. I was actually unaware of some of the theories regarding the projected future of the universe. Very interesting indeed.

Shadow12345
12-16-2002, 08:26 PM
I wonder if the universe only expands so far and then collapses upon itself. From there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from ...

MadHatter
12-16-2002, 08:29 PM
Originally posted by Shadow12345
I wonder if the universe only expands so far and then collapses upon itself. From there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from there it causes another big bang and then keeps expanding to that certain point and then collapses back on itself and from ...

...then what happens?

napkin111
12-16-2002, 09:27 PM
Maybe all the galaxies will do a big loop around the spherical universe and crash into eachother, creating a big bang....like if you have marbles inside a shpere (in zero gravity) and they collide at the bottom, move at the same rate around the inside of the shpere, only to collide at the top, starting the process over... Reading stuff like that makes me feel so small...

civix
12-16-2002, 09:27 PM
The theory I have heard is this:

Buildups of a "Dark Matter" or unknown force are accumulating at the universe's edges, rapidly expanding it.


Thus ends the strangest and most believable theory about this subject I have ever heard.

DavidP
12-16-2002, 10:00 PM
Well, I dont know where the universe ends or if it ends. But I do know one thing from all of my voyages into space. During voyage 749-A I came upon something very mysterious....

Here is a picture of what I discovered, maybe some of you can make out what it is....

Sebastiani
12-17-2002, 01:57 AM
Here is a picture of what I discovered, maybe some of you can make out what it is....

It's the end of the universe....aaaaaaah!

Solidarity
12-17-2002, 02:50 AM
I think the universe will just lock up and it'll go over to a black screen a say 'FAT32 UNIVERSE FAILED, SYSTEM HALTED'

Just a thought.

edit: Although I actually just dont care if the universe ends... Whats the point in worrying? If its gonna end, theres nothing YOUR gonna do about it! :)

alex6852
12-17-2002, 12:39 PM
>>what in the hell was 'there' before the big bang took place

Emptines. Nothing existed, even time (wierd huh?). There was olnly a tiny, tiny ball of magnificent energy, that was made of photons. Than one day it reached critical energy density and BANG!!! - now we have space time and matter.

adrianxw
12-17-2002, 01:26 PM
>>> what in the hell was 'there' before the big bang took place

Check out the "Membrane theory" I mentioned earlier. It describes the membrane multiverse in which our universe exists. Of course, this is just theory right now.

Brian
12-17-2002, 01:54 PM
read the book "A brief history of time", it's quite tough reading but it explains a lot of questions you may have.

Brian
12-17-2002, 01:56 PM
i think what steven hawking said was something along these lines...

if the universe were infinate, that would mean there were an infinate number of stars, which would mean the sky would be infinately bright with the infinate amount of energy emitted by these stars, so the universe can't be infinate.

DavidP
12-17-2002, 03:57 PM
if the universe were infinate, that would mean there were an infinate number of stars, which would mean the sky would be infinately bright with the infinate amount of energy emitted by these stars, so the universe can't be infinate.


Tell me if I am wrong, but I think the laws of physics could easily disprove that statement.



Emptines. Nothing existed, even time (wierd huh?). There was olnly a tiny, tiny ball of magnificent energy, that was made of photons. Than one day it reached critical energy density and BANG!!! - now we have space time and matter.


a magnificient ball of energy, eh? Well...that would be matter, wouldnt it? I do not think it would really be plausible for nothing to exist. Personally, I do not believe in the big bang theory, but for purposes of this post, let's just say it is true for now. If that tiny ball of magnificent energy existed, then matter existed.

Nothing cannot exist. Just think about it. Our human minds are not able to comprehend nothing.

Imagine the universe in all of its glories. Look upon the galaxies, the planets, and the stars. A great site, isn't it? Then delete all of that and make space and empty nothingness. Kind of dreary, isn't it? But it is still possible. But then, begin to think of the impossible. Imagine the universe with bounds and limits. It cannot be comprehended by the human mind.

In my mind, when I think of the universe with bounds and limits, I look at it as a sphere, kind of like our Earth. And then outside the sphere of the universe is a great white expanse of nothingness. But wait....that cannot be....if our universe ended, would not existence cease to exist also once the boundaries were hit? Therefore...if our human minds imagine some great expanse of nothingness, then that must be something. Just emptyness, but still something. Therefore the universe could not have ended. But then, imagine the universe did not exist. In fact, go even further, imagine existence did not exist.

When you imagine that the universe does not exist, what do you see? Just a great white expanse of nothingness? What is this great white expanse of nothingness? A template for existence? An instance in which all other instances are created?

But then, imagine that great expanse cease to exist. Imagine existence ceases to exist. There is no such thing as existence. What do you imagine then? Is your mind hurting trying to imagine it? Do not say you imagine a great expanse of nothingness, because that cannot exist if existence ceases to exist. If there was no existence, there would not even be nothing. Nothing implies empty space...but space itself would cease existence...so not even nothing would exist.

But the point I am trying to make is...the universe cannot be comprehended by man. It goes on endlessly and continuously. There is no end to it. I find it hard to believe that one day you could hit some boundary to the universe.

OneStiffRod
12-17-2002, 05:35 PM
I'm not a SPACE buff but I think the universe is ROUND - if you travel in a straight line you will eventually end up back where you started.

Clyde
12-17-2002, 05:53 PM
"Nothing cannot exist. Just think about it. Our human minds are not able to comprehend nothing"

Our ability or inability to comprehend something does not limit it.

"Therefore...if our human minds imagine some great expanse of nothingness, then that must be something"

It is something, it's a model in our heads.

"But the point I am trying to make is...the universe cannot be comprehended by man. It goes on endlessly and continuously. There is no end to it. I find it hard to believe that one day you could hit some boundary to the universe."

Your reasoning seems false; we cannot model the universe accurately in our heads, that however does not limit the actual characteristics of the universe.

There is no logical impossibility with the universe having an end or a beginning, in space or in time (although for a beginning and an end to exist in space you would have to define a direction which would be somewhat arbitrary).

We couldn't imagine it as you have pointed out, but that doesn't mean it couldn't be.

It certainly seems odd to think of hitting a "wall", and i really don't find the idea terribly plausible, i'm sure i've read somewhere (probably Hawking) that you end up back where you started, in the same way that you can walk "straight" forwards on the Earth and end up back where you started. You have an analogous situation in 3 dimensions for the universe.

minesweeper
12-17-2002, 05:58 PM
When I was doing A-Level physics I used to ponder over questions like this about the Big Bang and whether the universe has an end etc etc. And I used to think about all the little muons and taus and stuff randomly popping in and out of existence. Then I figured that it is all so mind blowing that my feeble brain would never be able to understand it. My advice, forget about it and wait for one of the superbrains like Stephen Hawking to figure it out. Then just buy the book he writes for lamen like you and I.

EDIT: That wasn't for Clyde, despite being after his post. He obviously knows far more than the average person and so probably wouldn't take kindly to being called a laman. :)

Aran
12-17-2002, 06:03 PM
the reason why we don't see nothing but the white of burning stars in the night sky is because some light hasn't even reached us yet past a certain point.

irrelevant:
in a LONG TIME the adromeda galaxy and the milky way are going to most likely colide, either flinging earth into two supermassive black holes or flinging earth out into empty space. (this is irrelevant, buti find it damn interesting)

napkin111
12-17-2002, 09:38 PM
The situation about why can't we see infinite stars is disproven by the fact that light diminishes with distance (shine a flashlight against the wall, back up and it gets dimmer[yeah, I know thats a kindergarten explanation, but its the best I got :P]), they mentioned it in the article also. Even if I am a layman I still like to think a bit dang it :P

//napKIN

PJYelton
12-18-2002, 09:47 AM
I could be wrong (been awhile since I've taken any physics) but I don't think light diminishes with distance, but instead disperses. A flashlight diminshes because the light is going in MANY directions from the source, so it gets spread out more and more the farther away you move. A straight laser beam that doesn't veer in any direction shot from billions of light years away will still reach us with the same intensity as it left with - ideally anyways!

Somebody back me up though, as I said I'm not sure :D

Sentaku senshi
12-18-2002, 10:05 AM
True, but the sun's rays by the time they reach earth are going in straight paths and no longer spreading well thats what I was told anyways

diagram

Sebastiani
12-18-2002, 10:33 AM
I think napkin meant diperse, anyway. Lasers are concentrated, but not as much as you think. A laser shot from just 10 miles away wil experience a spread of 5-50 feet - at least! Thus, from several billion miles away, the spread would be huge (though obviously more concentrated than an incandescent source).

David really hit the nail on the head though. Human conception is artificial, logic is limited, and thus just as labeling something as "empty" and "void" is contructing a "something", imagining "the end of the universe" is just as futile as visualizing the size of the sun. Inconcievable.

PJYelton
12-18-2002, 10:39 AM
Oh, I agree that lasers disperse. I guess I was talking about a perfect laser shot in an ideal (from a physics sense) universe would reach us from a billion light years away with the same intensity.

sentienttoaster
12-18-2002, 10:48 AM
I myself do not think there is an end to the universe. I have a couple of theories, I think that it could just loop itself, or that when you come to the end, you will get disoriented and turn yourself around and keep going in the direction you just came from!

Sebastiani
12-18-2002, 11:00 AM
Originally posted by PJYelton
Oh, I agree that lasers disperse. I guess I was talking about a perfect laser shot in an ideal (from a physics sense) universe would reach us from a billion light years away with the same intensity.



I see what you mean. Anyway, lasers are fascinating stuff. Did you know that you can carry your voice on one directly?

minesweeper
12-18-2002, 11:02 AM
If what Einstein said is true about space and time being one and the same thing (i.e. the space-time continuum). Does that mean if you were to travel to the edge of space, you would also travel to the 'edge' of time? And which 'edge' would it be? Or is this just another thing our minds can't comprehend?

Sebastiani
12-18-2002, 11:16 AM
What Einstein meant was that time and space can no longer be considered separately. This is not really relavant to two observers standing in the same reference frame, but rather, two observers in separate reference frames. If you are moving at 99% the speed of light relative to me, and I were to gaze into your spacecrafts window and at your watch, it would appear that both you and the watch were motionless. In fact, I would be viewing the nanoseconds of your life. On the other hand, were you to peer down at me, it would appear that all phenomena on earth was moving at a breakneck speed, literally watching the seasons pass as each were a single frame of film in a movie. I this sense, your two-o-clock would be incompatible with mine.

By the way, his theories have been proven, and so can be considered fact.

minesweeper
12-18-2002, 11:23 AM
>>By the way, his theories have been proven, and so can be considered fact.<<

hmmmmm.....I thought it was still a grey area, as they dispprove newton's theory of gravity. All to do with the orbit of Mercury round the Sun I think. It's in 'A Brief History of Time' if I remember. I mean they may have been proven, I don't really know. I just thought some people doubted the disprovability of newtonian gravity.

Clyde
12-18-2002, 11:24 AM
"Human conception is artificial"

As opposed to....... natural?

"logic is limited"

Based on what?

"and thus just as labeling something as "empty" and "void" is contructing a "something""

That doesn't make the label innacurate, merely our ability to imagine it.

Sebastiani
12-18-2002, 11:31 AM
Einstein never sought to disprove Newton. His theories are merely "specialized" cases of newtonian physics that are more accurate than newtons for high-speed physics. Interestingly, Einstein derived his theories mostly from the studies of Max Planc, Maxwell, and other experimental physicists. His real gift then was bringing together the results of many into a cohesive theoretical work, and to my knowledge, Einstein never had a lab other than his armchair. Pretty impressive, really. :)

Sebastiani
12-18-2002, 11:39 AM
>>"Human conception is artificial"

>>As opposed to....... natural?

If I ask you to imagine you were dying, you could construct a conceptual image, but this is not experiencing the "thing itself". Thus, conception by definition artificial.


>>"logic is limited"

>>Based on what?


What comes first, a chicken or an egg? Logic cannot solve this problem and infact, were you to propose the problem to a computer, it would fall into an infinite loop. Thus, logic is limited.


>>"and thus just as labeling something as "empty" and "void" is contructing a "something""

>>That doesn't make the label innacurate, merely our ability to imagine it.

You're right but the point is, you can only imagine in an existential sense, not in a "void" sense.

minesweeper
12-18-2002, 11:40 AM
Oh yeah I'm not doubting what he did, fabulous really, especially the radical, previously unthought of nature of his theories. When I read about relativity in 'A brief history of time', I don't know, it kind of just made sense. All I was saying is that in that book it mentions something about the orbit of Mercury (it's certainly the orbit of something about something else). Apparently the orbit's orientation changes slightly over time and this is not predicted by newtonian gravity but it is by Einstein theories. Because of this, Einsteins theories ruffled a number of feathers in the world of Physics. But yeah, one clever guy, probably the cleverest.

Sebastiani
12-18-2002, 11:45 AM
I'm sure at some point in the future, someone will come along and prove his theories to be mere approximations of even more superior theories.

Clyde
12-18-2002, 11:46 AM
"If I ask you to imagine you were dying, you could construct a conceptual image, but this is not experiencing the "thing itself". Thus, conception by definition artificial."

...... hrrmph i do not think the terms artificial or natural are usefull in this context, imagining != experiencing.

All of our perceptions are internal models, we do not percieve reality as it is, but to label them 'artificial' seems to be implying something else, having said that its just a semantic point.

"What comes first, a chicken or an egg?"

The egg.

"Logic cannot solve this problem"

How is it then, that i solved it?

"were you to propose the problem to a computer, it would fall into an infinite loop. Thus, logic is limited"

Logic is not limited, the question is flawed (or atleast, the classical way of approaching the question is flawed), because it makes an invalid assumption.

"You're right but the point is, you can only imagine in an existential sense, not in a "void" sense."

Agreed.

Clyde
12-18-2002, 11:48 AM
" Apparently the orbit's orientation changes slightly over time and this is not predicted by newtonian gravity but it is by Einstein theories"

I think what you are talking about (i may be completely off) is the way we can see light bend around a massive obect (like a planet), simply using Newtonian mechanics the bend predicted falls short of the one observed, using relativistic theory we get accurate predictions (its to do with light following curved space)

Sebastiani
12-18-2002, 11:52 AM
"What comes first, a chicken or an egg?"

The egg.

"Logic cannot solve this problem"

How is it then, that i solved it?

"were you to propose the problem to a computer, it would fall into an infinite loop. Thus, logic is limited"

Logic is not limited, the question is flawed, because it makes an invalid assumption.


Touche! :D



...... hrrmph i do not think the terms artificial or natural are usefull in this context, imagining != experiencing.

All of our perceptions are internal models, we do not percieve reality as it is, but to label them 'artificial' seems to be implying something else, having said that its just a semantic point.


That's a good point. A better word than 'artificial' might be 'non-actual'. I just mean that conception will never measure up to what is being concieved of.

adrianxw
12-18-2002, 01:18 PM
>>> What comes first, a chicken or an egg?

The egg. The two parents were not sufficiently chicken like to be called chickens, but their combined genetic material produce a mutation which was now sufficiently chicken like to be called a chicken. Thus, there was not a chicken prior to the production of the first chicken egg.

An esoteric point, but the fertilised egg cell was already destined to be a chicken before it was encased in the hard shelled "egg".

Sebastiani
12-18-2002, 01:50 PM
And you see nothing subjective about that point of view? Besides, who decides what's "chicken enough" anyway?? :p

Brian
12-18-2002, 02:16 PM
Originally posted by napkin111
The situation about why can't we see infinite stars is disproven by the fact that light diminishes with distance (shine a flashlight against the wall, back up and it gets dimmer[yeah, I know thats a kindergarten explanation, but its the best I got :P]), they mentioned it in the article also. Even if I am a layman I still like to think a bit dang it :P

//napKIN

yes but with an infinate amount of stars
there would be an infinate amount of light
so all the particles that diminish the light
would be so super-charged with energy
they would glow too and it would just become
infinately bright.

napkin111
12-18-2002, 03:34 PM
Originally posted by Brian
yes but with an infinate amount of stars
there would be an infinate amount of light
so all the particles that diminish the light
would be so super-charged with energy
they would glow too and it would just become
infinately bright.

Ah but there are black holes, which do not reflect light. They just suck it in...And I'm not sure that light like that could "super-charge particles enough that they would glow.

//napKIN

Brian
12-18-2002, 05:56 PM
think about infinity.

infinity means there is no limit to it.
so if you have inifinity stars, everywhere would be 100% star.