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Where Does Space End? It Must End Somewhere!


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half a quark

With regards to the Universe size:     So, just for the record; It isn't an issue of - could, not - 50%, not even 99.99%. The Universe is Infinite by 100%.

matter cannot always be divided into smaller protions. do the words "elementary particles" mean anything to you?

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Infinite amount of 4 dimensional planes doesn't even make sense, imo. IIRC, a plane is 2D by definition. Are you sure you don't mean "Brane"? If so, then it is NOT a "well known fact", but rather speculation based on a dying "theory".

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I actually said SPACES

4D SPACES.

It's really well known, trust me

 

It looks like you said planes. Even if you did say spaces, why an infinite number of them? Why not one? Sorry, but it looks like you're backpeddling to me.

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It's a well known fact that space consists of an infinite amount of 4 dimensional planes, though if we're speaking in the fourth dimension, it's spaces.

 

Would you mind citing a reputable source, where it specifically states that please.

 

The Elegant Universe Written by Brian Greene... Good book I would (and probably antimatter) recommend it.

 

Elegant Universe, written by Brian Greene,

very well known, very reputable.

 

wow... I guess we both really like that book

 

Dark and antimatter, I hope you will update your understanding by reading something more recent with a different line of speculation. Even a more recent Brian Greene book (like Fabric) might help you.

 

A lot of what he says is speculation rather than "well known fact". Back in the 1990s there was a lot of wild optimism about string/M theory (Brian Greene himself recently acknowledged this in an interview that is online, he called it "youthful optimism"----talking about a promised Theory of Everything).

 

In the 1990s and even into this century like 2000-2002 a lot of stuff was widely bought that was verging on fantasy and wishful thinking. So you have to be careful.

 

A little bit more critical about what you may have read. We can't take the time to check everything. You have to do it yourself.

Read more recent sources. "Elegant" is old.

 

For starters here is a 2007 interview with Walt Isaacson, Paul Steinhardt, and Brian Greene.

Listen to Steinhardt. He has major scientific stature, which Greene does not.

(not that I buy everything Steinhardt proposes either, but his research is far more cited than Greene's)

 

http://www.edge.org/3rd_culture/einstein07/einstein07_index.html

 

==sample exerpt==

ISAACSON: Why is there such a personal theological argument...—that when people start debating string theory their faces turn red.

 

STEINHARDT: I think it's for the reason that I was beginning to raise. In my view, and in the eyes of many others, fundamental theory has crashed at the moment. Instead of delivering what it was supposed to deliver—a simple explanation of why the masses of particles and their interactions are what they are—we get instead the idea that string theory allows googols of possibilities and there is no particular reason for the properties we actually observe. ...In my own view, if I had walked in the door with a theory not called string theory and said that it is consistent with the observed laws of nature, but, by the way, it also gives a googol other possibilities, I doubt that I would have been able to say another sentence. I wouldn't have been taken seriously.

 

GREENE: You really think that? I don't mean to get technical, but take the standard model of particle physics,... The masses of the particles can be changed arbitrarily and the theory still makes sense, it's internally consistent; you can change the strengths of the forces, the strengths of the coupling constants...So how is that any worse than string theory?

 

STEINHARDT: Well I think there is a key difference, which is that no one believes the standard model is the ultimate theory, and string theory is claiming to be the ultimate theory.

 

GREENE: Oh, I think we should put claims of that sort…

 

STEINHARDT: But the question was raised, why are people upset about it? And the answer is, because whether you personally believe it or not, string theory has been advertised as being the ultimate theory from which we should be able to understand…

 

GREENE: I guess I would say it is unfortunate that people get worked up over that kind of advertising. If you look at the history of string theory, I agree with you; there was a time when people thought this could be it—the final theory ...

But I think there was a certain kind of youthful exuberance that took hold when the theory was in its early infancy in the 1980s and early ‘90s and so forth, which perhaps was a little bit unfounded because it was such an immature theory that you really couldn't make pronouncements ...

But I think the most sober way of looking at it is that we have quantum mechanics, we have general relativity, we have to put them together in some consistent way, string theory is a possible way of doing that, and therefore we should explore it and see where it goes. ...

 

STEINHARDT: That's a stupendous retreat from what many people have claimed.

 

GREENE: You really think so?

===endquote===

 

Steinhardt is clearly referring to Greene's books and TV serials, which were a major vehicle for the early overselling of string, among other things. He's implicitly asking Brian to face up to this. When he says what "many people" have claimed, that points the finger right at Brian.

 

Steinhardt is at Princeton. When Alan Guth thought up cosmological inflation in 1980, Steinhardt was one of three people who independently discovered how to make it work. What we call inflation scenarios are to a considerable extent Steinhardt's invention, and he has made other major contributions. Including to string.

 

this is the closest thing to a public spanking Greene has been given by anyone who could be said to belong to the string "camp", that I know of.

 

This only goes a little ways. there is a lot more to realize and assimilate. If you are still thinking of "Elegant" as authoritative source material, then chances are you have some catching up to do. I don't wish to sound critical of "Elegant", but only point out that it is a 1990s book and is of its historical period.

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there is no end to space... thats just like asking when time ends...

 

for a concise argument, that is very astute.

at what time of day does time end? at 11:45 in the morning, say? :D

 

as you point out an analogous reasoning applies to space.

In modern cosmology, space has no boundary. (what could one look like?)

 

As far as I know, for at least 400 years no educated person (no scientist anyway) has supposed space to have a boundary. But my knowledge of history is patchy. I know a little better the thought of the past 50-100 years. Again AFAIK, for astronomers at least, no boundary.

 

So this thread has always puzzled me. What can it be about? The title of the thread "It must end somewhere!" is obviously wrong so what is the discussion about?

 

Anyway, thanks for the concise summary, T man.

Great quote from Jefferson, that I'd never seen before.

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here is something to think about: once you've drawn a circle, where is the beginning and where is the end? Once the universe was "born" couldn't it be like a circle? and have no start of finish? just endless corners to look around?

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Alright, if it may, our unlimited 4d coordinate plane may not be an idea many people believe in, or to quote yourdadonapogos, "a dying theory". However, we do still have a right to our beliefs and it is good to challenge them but, we do not really need a trustworthy source behind us and I believe no one should contradicted straight off the bat on such topics we know such little about.

 

-Dark Matter

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errr...I read Fabric of the Cosmos...

 

I'd say that is definitely a step in the right direction! Elegant first came out in 1999 and Fabric first came out in 2004. So it is more recent.

Knowledge about the universe is changing fast so other things being it makes sense to read the more recent stuff you can. In line with that,

 

Paul Steinhardt's book about the cosmos was published in May of last year

May 2007

http://www.amazon.com/Endless-Universe-Beyond-Big-Bang/dp/0385509642

The cheap paperback edition of Steinhardt comes out next week ( June 3 2008)

http://www.amazon.com/Endless-Universe-Beyond-Rewriting-History/dp/0767915011

 

You may think I am recommending. I'm not. I don't like Steinhardt's cosmology. I don't normally read popular science books and I havent read this one. I've read his professional papers and I don't like Steinhardt's cosmology.

 

To let you know where I'm coming from, I am more likely to get this new book from the library when it comes out JULY 1 2008

http://www.amazon.com/Beyond-Big-Bang-Prospects-Collection/dp/3540714227

"Beyond the Big Bang" (collection of articles by 20 or so experts. Steinhardt will be included I expect, but Greene I doubt will because he doesnt have adequate standing in talking about the universe. He is more for the popular market.)

Here is the Table of Contents for that new book "Beyond the Big Bang".

http://www.springer.com/astronomy/general+relativity/book/978-3-540-71422-4?detailsPage=toc

We will know more in a month or two.

You have to decide for yourself what sources to teach yourself from. Basically I just want to give you some perspective. The only advice I can give you (and this is just personal opinion) is

1. Don't read popular science if you can possibly avoid it.

2. Read the MOST RECENT stuff by reputable people that you can get hold of and understand.

3. Among the stuff published SINCE 2005, go for the most reputable people writing about current models of the universe. these are the most highly CITED authors and the ones regularly invited to give featured talks at international conferences specifically about the universe

 

that is, the ones that other people cite in their research as references, and who give the featured invited talks at COSMOLOGY conferences. they are the ones with cred.

 

If you want, I can tell you who these people are or you can use search tools that give citation ranking and get the info for yourself.

 

 

... we do not really need a trustworthy source behind us and I believe no one should contradicted straight off the bat on such topics we know such little about.

 

-Dark Matter

 

I urge you to believe that you do need a source. For productive discussion. You should be able to give links to what you are basing your statements on. At a science board like this we are rarely interested in mere unsupported personal beliefs. Individual notions, purely personal ideas about the universe, really belong in a separate "speculations" forum.

 

What I'm hoping is that you will read some more, even if it is just the Scientific American. and talk to us about that. whatever it is you read---knowledge about the universe is changing rapidly! so make it RECENT, like since 2005.

 

As I say, I don't particularly like Steinhardt's cosmology and I havent read his 2007 popular book, but that would still be fine with me. Whatever is recent and by real scientists is good grist for the mill :)

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However, we do still have a right to our beliefs and it is good to challenge them but, we do not really need a trustworthy source behind us and I believe no one should contradicted straight off the bat on such topics we know such little about.

 

But.....

 

Belief is not truth and belief is not knowledge. It is knowledge and truth that science is about. It is the job of science to contradict and challenge that which is proffered from belief alone. It is the job of science to seek trustworthy proof. If you do not want contradictions then proffer your beliefs over in some "faith" forum. If you want to proffer them in a science forum then expect to be challenged.

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I can't agree with Dark matter that we don't need sources, we definitely do, but I also read a book from 2005 that said this as well.

http://www.amazon.com/Big-Bang-Universe-Simon-Singh/dp/0007162200/ref=sr_1_1?ie=UTF8&s=books&qid=1212245041&sr=8-1

 

I'm not entirely sure if that's what you'd call pop-sci, but as far as I've heard it wasn't very 'mainstream'.

 

Thanks for the links Martin, I'll definitely look into them.

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"I urge you to believe that you do need a source. For productive discussion. You should be able to give links to what you are basing your statements on. At a science board like this we are rarely interested in mere unsupported personal beliefs. Individual notions, purely personal ideas about the universe, really belong in a separate "speculations" forum."

 

good point.

 

I can't agree with Dark matter that we don't need sources, we definitely do, but I also read a book from 2005 that said this as well.

http://www.amazon.com/Big-Bang-Universe-Simon-Singh/dp/0007162200/ref=sr_1_1?ie=UTF8&s=books&qid=1212245041&sr=8-1

 

I'm not entirely sure if that's what you'd call pop-sci, but as far as I've heard it wasn't very 'mainstream'.

 

Thanks for the links Martin, I'll definitely look into them.

 

I was saying we don't need sources to support a speculation.

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Agreed, iNow, but this isn't really speculation...I gave sources (Big Bang, Fabric of the Cosmos), but then again, I should have given less 'pop-sci' sources.

 

Hi antimatter,

 

I was actually responding this:

 

I was saying we don't need sources to support a speculation.
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Yes. It usually begins on a foundation of existing knowledge and information.

 

Good point inow. What was my original "speculation" anyway... oh right our unlimited four dimensional plane. What was wrong with that idea anyway?

 

(yes, I know I'm backpedaling, you've won this battle, but not the war)

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Okay, that's what I mean.

Dark matter phrased it wrong, to deal with post 313,

and 316 just confirms what I said.

It's not really all that wrong (sure it has flaws, but so do most other theories), it's just being replaced.

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