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The assumption of bounded/unbounded space


pywakit
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At the risk of annoying anyone, I would like to weigh in here. Mind?

 

Last winter, when I was discussing my model with Dr. Neil DeGrasse Tyson ( name thrown in to lend credibility ... lol ... but I actually was ) I made the comment that 'space was infinite'. His response was "It is assumed to be so, but we have no proof." My rebuttal ( roughly ) was "We have Einstein's math, corroborating experiments, and observations. Einstein said space is uniform, unless disturbed by mass. Logically it makes sense that our 'local' universe would exist in curved space because all that mass/gravity is curving it. But why would anyone think that space only exists for the pleasure of our 'local' universe?"

 

He said ... "Because we can't see it. If we can't see it we cannot logically claim it to be fact. But, as I said, most scientists assume it to be so." ( infinite )

 

So at least Dr. Tyson and I agree in 'opinion'. Lol. But I think we have more than enough evidence to claim infinite space as a reasonable conclusion ... and a good part of a working model of the universe.

 

It seems so clear to me. Space Is Uniform. That means it is 'the same'. Homogenous. Isotropic. I see infinity as a 3 dimensional straight-line grid with all lines extending to infinity. There is no shape, because shape has limits.

 

I was 6 years old when I read this 'space is uniform' thing. I was very curious about the universe, and from what I already knew ... it seemed obvious that the universe would have no end. So Einstein's math just 'confirmed' what I already knew. It was a little distressing when I kept seeing 'the' universe described as a 'curved' finite structure. The very idea that space would simply cease to exist because 'our' local universe wasn't there to 'occupy' it seemed completely irrational.

 

 

It assumed therefore that our little home was the only universe that has ever existed. That nothing else exists except for 'us'. That when we are gone, nothing will ever exist again. This isn't logic. This is religion.

 

"We are special. We are here for a reason."

 

"Oh really? Says who?"

 

"Uhhhh. Well, 'we' do."

 

"Ohhhhhh. Sure. I get it."

 

Space is uniform. We can twist logic to placate our 300,000 year old ego, but it doesn't change the fact. We have mountains of evidence that space is uniform. Isotropic. None that space ends at our borders ... whether or not we can see it.

 

Within our local universe, our straight lines are an illusion, because gravity is curving space. So to say we can go for infinity in a straight line yet never go beyond the finite bubble is also an illusion. The lines in our local universe aren't 'straight'. They just look straigtht.

 

( edit )

 

To take the weakest possible stance we can rationally and logically say ... "Infinite space is inferred, while finite space is not."


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Thousands of years ago, when Man began to seriously contemplate his universe, he wondered how big it was. There were a host of reasons to come to the conclusion that the 'physical universe' ... the one 'he' could see must be finite. Meta-physical? Not so finite.

 

The ego gene was a great survival trait. We could plainly see that we were far superior creatures to all other species. A strong piece of evidence for our 'special' status. But the ego gene has it's drawbacks, too. It clouds reason, and allows us to formulate concepts ... like logic ... that we unconsciously shape to suit our desires.

 

Now, many thousand of years later ... 'science' ( being less than a few hundred years old ) has royally decreed ... that our current scientific methodology is a 'perfect' tool for scientific inquiry. And we have never looked back. Why would we? Look how well it has worked! This logic is flawed, of course. Look how badly it has failed, too.

 

The point I am trying to get across is ... we have never had a good reason to believe we are the only intelligent life in the universe, or that our universe is finite, or the only one. In fact, true logic ... unadulterated by ego ... says that if it's possible for us to exist, then it's equally possible 'we' ( and I do mean we. Exactly the same as us ) could exist other places. That other universes could exist in other places.

 

There never WAS a good, scientific reason to believe that our universe was finite. We looked around us and just 'decreed' that it was. I mean, it had to be. Why else would we be here? There HAS to be a reason. We are so SPECIAL! Just Ego. Lol.

 

When I was a kid, the 'universe was 'closed', like now. It consisted of the MW with around 250M to about 2B stars. There were maybe a 'few thousand' other galaxies, and a few things we couldn't identify. And science took the 'logical' stance that this could be 'all there was'. On the otherhand, there could be all kinds of 'anything is possible' stuff.

 

As the universe threw it's arms open to us, we realized that our thinking was a mite small. And incorrect. Not only was it obviously bigger by several orders of magnitude, but all those 'possibilities' turned out to be non-existent. The universe was essentially the same wherever we looked. Just like it was when we looked 50 years ago ... when anything was possible. And even though we can see 'infinitely' farther than we could before, and found none of these fantastic 'possibilities' ... the mantra remains the same.

 

ANYTHING is possible beyond our field of view. And here is the really amusing hypocrisy. We claim ( chaos theory, Heisenberg principle ) that anything is possible because the math says so. There's a CHANCE. Lol. Our universe has INFINITE possibilities. So all things can happen!

 

Funny. How did you get infinite possibilities from a finite universe?

 

It's past time we change our thinking. It's time to come to the rational conclusion that we exist in a finite, expanding bubble of gravity within a universe that is actually infinite ... until proven to be finite. Not the other way around.

 

Moo, you said this is to be a debate, not a lecture. I hope I am not crossing the line. I just thought making some reasonable observations might be in order. I think all my statements have been truthful and accurate.

 

Could be wrong, though. Lol.

 

Wish I was more eloquent.

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pykawit wrote

Our universe has INFINITE possibilities. So all things can happen!

I disagree. I think that "infinite possibilities" is not coherent with the laws of physics. We have been showed by Mother Nature that things have to obey (??how is that possible???) laws.

I would prefer to define the Universe as the sum of non-contradictory possibilities.

 

But we are missing the point. "Space" is different from "the Universe". Or isn't it?

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'Wakit you have a lot of mistakes here. You sound so sure of yourself that no one is likely to want to try to correct you.

 

In cosmology we don't assume that the universe is exactly homogenous and isotropic. That is assumed to be true only as a largescale approximation.

Moreover it is not an assumption about empty space devoid of matter. It is an assumption about distribution of matter.

 

The distribution of matter is assumed to be co-extensive with space and to be approximately uniform (homog. and iso.) in the largescale average.

 

That's one mistake.

 

Another mistaken idea you have is that homog. and iso. imply infinite.

 

There are many cosmo models which satisfy the uniformity principle which have space be a finite volume, with a finite circumference. They have been studied for years and are well-known. That case has not been ruled out and NASA published an estimated lower bound on the size just this year.

As I recall it amounted to a circumference of about 600 billion light years.

That was a blue-ribbon NASA report from the WMAP mission.

 

So it is ridiculous to claim that uniform implies space infinite. It is not rational. Counterexamples abound!

 

If you don't already understand this, then you need to be asking questions at this forum, not making statements.

 

Sounds like DeGrasse-Tyson was trying to explain, but couldn't take the time to hammer it in. He probably had to oversimplify and leave out part of the message, but he gave you the important part. We don't know whether space has finite volume or infinite volume. We assume matter is coextensive with space, distributed approx uniformly (the structure looks cob-webby at smaller scale and clustery at even smaller, galactic, scale).

As new data comes in, it is analyze and the results are tabulated using both the finite and infinite models because we don't know yet.

 

But we are getting closer to knowing, so stay tuned.


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I vote that we create a stickied thread about the space ending vs. not ending debate. The first post should be detailed giving a basic reading to a more advanced reading.

 

Space having a finite volume does not imply that space "ends" anywhere or that space has a boundary.

 

In cosmology we normally assume that space does not have a boundary.

It's simpler that way. Einstein's model(s) of the universe did not have a boundary, and all their descendent models worked out by other people so nor have boundaries.

 

And typically matter is approximately uniform and coextensive with space, so if space has finite volume there is a finite amount of matter.

 

And if space has infinite volume there must be an infinite amount of matter.

 

In either case (finite or infinite) there is no border of any sort, no "end", no boundary, to space-and-matter.

 

I'm not talking about singularities, where in some models if you go back far enough in time the model might terminate. That's a separate issue, although it terminates spacetime it's not a boundary to space in the sense we're talking about. Nor is in other cases if you go far enough into the future and get a crunch singularity.

Cosmologists are developing models that don't have those breakdown points---don't have singularities---so that kind of terminus is gotten rid of as well, but that's a different issue.

 

I don't know if your idea of sticky thread is good. It is not a debate for amateur philosophers though. It is a place where if you don't understand conventional standard cosmology you should start asking questions.

Whether or not a sticky is good, I don't know. What experience has shown, though, is that people who come into a discussion like this should start by asking questions until they understand the ordinary professional working astronomers' picture.

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'Wakit you have a lot of mistakes here. You sound so sure of yourself that no one is likely to want to try to correct you.

 

In cosmology we don't assume that the universe is exactly homogenous and isotropic. That is assumed to be true only as a largescale approximation.

Moreover it is not an assumption about empty space devoid of matter. It is an assumption about distribution of matter.

 

The distribution of matter is assumed to be co-extensive with space and to be approximately uniform (homog. and iso.) in the largescale average.

 

That's one mistake.

 

Another mistaken idea you have is that homog. and iso. imply infinite.

 

There are many cosmo models which satisfy the uniformity principle which have space be a finite volume, with a finite circumference. They have been studied for years and are well-known. That case has not been ruled out and NASA published an estimated lower bound on the size just this year.

As I recall it amounted to a circumference of about 600 billion light years.

That was a blue-ribbon NASA report from the WMAP mission.

 

So it is ridiculous to claim that uniform implies space infinite. It is not rational. Counterexamples abound!

 

If you don't already understand this, then you need to be asking questions at this forum, not making statements.

 

Sounds like DeGrasse-Tyson was trying to explain, but couldn't take the time to hammer it in. He probably had to oversimplify and leave out part of the message, but he gave you the important part. We don't know whether space has finite volume or infinite volume. We assume matter is coextensive with space, distributed approx uniformly (the structure looks cob-webby at smaller scale and clustery at even smaller, galactic, scale).

As new data comes in, it is analyze and the results are tabulated using both the finite and infinite models because we don't know yet.

 

But we are getting closer to knowing, so stay tuned.

 

Lol. Martin, I am reminded of all the 'blue ribbon' reports that have come down the pike in the last 500 years. Like the Vatican's trial of Copernican theory. Once you science guys get a mind set there's no stopping you. Especially when a knothead like me challenges 'conventional wisdom'.

 

Why the disrespect? 'Wakit? Hmmm. This sends a subtle message to others that I am a little 'whacked out', does it not? Yes. it does. Shame on you.

 

Ok, then. Lol. Not to point out the obvious, but since you have opened the door .... Having a picture of Alfred E. Newman as your thumbnail does not exactly instill confidence in your statements. Lol. I will be back after dinner to rebutt the 'lots of mistakes' you claim I made.

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Py,

I'm shortening your name for friendlies. If you don't like Wakit you can be Py. No disrespect at all!

If you don't like Py, tell me. I think it's a nice familiar nickname but maybe it doesn't fit you.

 

Astro/Cosmo is for conventional scientific consensus Astro/Cosmo.

It is not for "against the standard model" or for Personal Theories.

 

Personal or Individual theories go in Speculation Forum

 

Part of our job is educational about standard science, so we sort things out from time to time to keep a modicum of order. If you want to explore a variant, show that you understand the standard model first.

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Ok. Sorry for stooping to that level. It's so funny. I was admonished on another thread for starting off with ... "I'm not that smart." 'Doesn't lend any credibility to your theories'. I was told. And then that was immediately followed by another admonishment for being 'egotistical'. Can't win. Lol.

 

Just read your message. I didn't put this thread here. Or are you talking about my model? If somebody wants to move it, it won't bother me. As far as 'accepted science', I am in almost complete agreement with you. Where I differ is where you insist that we stay within the bounds of mainstream theory. Since I am proposing nothing that requires 'new physics' or magic to make the model work, I fail to see how this violates the 'known and accepted' physics rule.

 

So may I go ahead and rebutt your assertions now? Thanks. And Py is fine. You do know who Pywakit was, don't you? Just a little whimsy from a non-theist.

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Py - Chill out. I'm frankly surprised that Martin has bothered wasting any time at all with you. The least you could do is to lose the attitude and see about improving your own understandings since he has offered to help in doing so.

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iNow, your own attitude is very off-putting to someone who is just trying to post his own ideas. You may have the best of intentions when you make your posts, but you must realize that the attitude you give off with them has unintended negative effects. Please try to be nicer.

 

pywakit, seeing as this thread was split off from another and it's now basically "yours", go for it.

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Originally Posted by Martin

'Wakit you have a lot of mistakes here. You sound so sure of yourself that no one is likely to want to try to correct you.

 

In cosmology we don't assume that the universe is exactly homogenous and isotropic. That is assumed to be true only as a largescale approximation.

Moreover it is not an assumption about empty space devoid of matter. It is an assumption about distribution of matter.

 

The distribution of matter is assumed to be co-extensive with space and to be approximately uniform (homog. and iso.) in the largescale average.

 

That's one mistake.

 

we don't assume that the universe is exactly homogenous and isotropic

 

Alright. We have an immediate problem.

 

1. Your use of the word 'universe'. Please be more specific. So you mean the hypothetical model that is 600 billion light years across? Or just our visible local universe.

 

2. I never said 'exactly'.

 

3. You wrote "Moreover it is not an assumption about empty space devoid of matter. It is an assumption about distribution of matter.

 

The distribution of matter is assumed to be co-extensive with space and to be approximately uniform (homog. and iso.) in the largescale average.

Again, where? In that 600 billion light year universe? And are we talking about distribution of matter in our local universe as opposed to that 600B one? One would think there is a distinction. What do those models predict for density of matter out side our local universe?

 

But in general terms, I agree. There will be 'approximate' isotropic distribution of matter in the local universe. I think it is safe to say that 'distribution' number is significantly lower when looking at the 'universe' outside our universe.

 

You wrote:

 

Another mistaken idea you have is that homog. and iso. imply infinite.

Logic says they imply one of 3 things. Infinity. Finite. Or Nothing. Lol. Feel free to make your case for 'Finite', or 'Nothing'. Uniformity of space at the very least 'infers' infinity. What evidence do you have to refute that other than 'theoretical models' that 'satisfy' a finite universe, but require ( let's face reality here ) magic, or re-writing physics? I have said this so many times. Mathematical probability/certainty does not equate to actually existing.

 

You wrote:

 

There are many cosmo models which satisfy the uniformity principle which have space be a finite volume, with a finite circumference. They have been studied for years and are well-known. That case has not been ruled out and NASA published an estimated lower bound on the size just this year.

As I recall it amounted to a circumference of about 600 billion light years.

That was a blue-ribbon NASA report from the WMAP mission.

Do I read this correctly? A 'lower bound'? Hmm. Ok. What's the 'higher bound'. My gosh. You scientists really have a hard time with infinity don't you? Lol. I have always loved the 'safety in numbers' defense. Works great if you are an antelope. I have said this before too. There is no safety in numbers. There is safety in truth.

 

Well, anyway I'm seeing a small problem because our expanding bubble of matter/energy is estimated by some to be around a 156 billion light year diameter. Others are still stuck at about 90. So what's the average dens ... oh never mind. Lol.

 

You wrote:

 

So it is ridiculous to claim that uniform implies space infinite. It is not rational. Counterexamples abound!

 

Oh really? Name one. Hypotheticals don't count. It's ridiculous to claim uniformity implies 'finite'. Or nothing.

 

You wrote:

 

If you don't already understand this, then you need to be asking questions at this forum, not making statements.

 

Well, I do ask questions. I have never claimed to be 100% certain. I have invited one and all to tear apart anything I say. I have to make the statements before you can debate them ... I assume. Or was I supposed to just accept that I couldn't possibly know as much or more than you about the universe ( cosmologically speaking ) and just study all the wonderful posts you all have made for the last year. Incredibly, I did not come up with any of this by reading tarot cards.

 

That said, I do not deny for a second that you all have a skill set far beyond my abilities. That does not preclude me from generally comprehending the evidence. Or looking at the problem with fresh eyes. It shouldn't take any of you but a few seconds to dismantle some crack pot idea, and kick the offender to the curb. I couldn't help but notice many of you tend to get a little emotional over this ....

 

Really. You should be a little more open-minded. "Out of the mouths of babes." You never know who is going to come up with an excellent idea. Edison never went to college. Wonder if he would have passed muster with you all.

 

You wrote:

 

Sounds like DeGrasse-Tyson was trying to explain, but couldn't take the time to hammer it in. He probably had to oversimplify and leave out part of the message, but he gave you the important part. We don't know whether space has finite volume or infinite volume. We assume matter is coextensive with space, distributed approx uniformly (the structure looks cob-webby at smaller scale and clustery at even smaller, galactic, scale).

As new data comes in, it is analyze and the results are tabulated using both the finite and infinite models because we don't know yet.

 

But we are getting closer to knowing, so stay tuned.

 

Sounds like you made another incorrect assumption. Dr. Tyson had plenty of time to explain. And his point was totally understandable. But he is not infallible. Einstein wasn't. Galileo wasn't. Newton wasn't. Why would I assume Neil wasn't? And why would I assume I'm not, either?

 

I also assume matter is coextensive with space. But there simply is no evidence of any kind that infers space is finite. It is pure speculation. Inferring space is infinite is reliant on math, experiments, and observations.


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No.

 

Lol.

 

 


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Py - Chill out. I'm frankly surprised that Martin has bothered wasting any time at all with you. The least you could do is to lose the attitude and see about improving your own understandings since he has offered to help in doing so.

 

Sorry you feel I need to chill. I was just being playful. I didn't really care that Martin called me 'wakit' It made me laugh. Hence all the lol's ...

 

Always up for improving my understanding. That's what it's all about right? But don't expect me to just accept what I am told as 'fact'. People make mistakes all the time. Again, I am not challenging conventional physics. Just conventional wisdom. New ideas are good. Yes? I have heard most of the 'old ideas', and I have found them lacking in one way or another. Not the physics, per se, ( although the reliance on unproven/untested superphysics is reasonable grounds for debate ) My problem, and it should be yours too, is the reliance on the hpotheticals. You give them a life of their own. An undeserved life.


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iNow, your own attitude is very off-putting to someone who is just trying to post his own ideas. You may have the best of intentions when you make your posts, but you must realize that the attitude you give off with them has unintended negative effects. Please try to be nicer.

 

pywakit, seeing as this thread was split off from another and it's now basically "yours", go for it.

 

Thank you. Feel free to reign me in when I get out of line ...

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Lots of errors, too many to address the whole batch. Here's a logic error.

homog. and iso. do not imply space is infinite

Logic says they imply one of 3 things. Infinity. Finite. Or Nothing. ...

Thank you. Feel free to reign me in when I get out of line ...

 

Consider yourself reigned in. Here we are talking simple logic. Not science. Not physics. Not astronomy.

 

I point out that A does not imply B.

You say "logic says" that therefore A must imply something else, like maybe not-B. That is an elementary non-sequitur.

 

Py I simply do not have time to correct all your mistakes. I will get back to this as time permits and point out a few more.

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Lots of errors, too many to address the whole batch. Here's a logic error.

 

Consider yourself reigned in. Here we are talking simple logic. Not science. Not physics. Not astronomy.

 

I point out that A does not imply B.

You say "logic says" that therefore A must imply something else, like maybe not-B. That is an elementary non-sequitur.

 

Py I simply do not have time to correct all your mistakes. I will get back to this as time permits and point out a few more.

 

Ok. Thanks. So should I assume that isotropy does not imply 'finite' either? If so, then how have you, or anyone else arrived at the presumption that it IS finite? Where is your actual evidence? The math? The obsevations? Or do you presume it because it sounds good to you?

 

My 'logic' is not a stand alone elementary exercise. It is a rational look at all available evidence, and arriving at a reasonable 'working' model. I do not make assumptions. I do not 'assume' the universe is either finite, or infinite. I am just reporting what the evidence infers without preconceptions. At least, that's what I am trying to do. It seems you are the one jumping to false, and unsupported conclusions ( no offense ) about me, my understanding of the universe, my familiarity with the standard model, or other models.

 

Attack my model. Or my facts. Not me. Fair? I have already conceded your intellectual superiority. Now prove it is actually superior in this field. Have yet to see the evidence.

 

Safety in numbers is not evidence. So how many 'hypothetical' models are out there anyway? Quite a few. What makes you think any of them are right? Certainly, at best ... LOGICALLY ... only one COULD be right. All pretty bright people. How could so many be wrong? Or is that too logical an exercise?

 

The fallback position of continually repeating I am too obtuse to understand gets tiresome. You have yet to point out an actual flaw with my reasoning, or my facts. Your perception that it is flawed ( and you just stating that it is flawed ) does not guarantee the flaw. Is it conceiveable to you that YOUR reasoning might be flawed? I don't think it is. It certainly is conceivable to me that mine might be .....

 

Your 'blue ribbon panel' ( very impressive, I must say ) has made a presumption of a finite universe as a working model. If it has boundries ... whether 600 billion light years or 600 septillion light years squared ... it's finite. What is that presumption based on?

 

How many brilliant people made similar arguments to yours when defending the steady state universe? The evidence for an expanding universe was pouring in. Did the brilliant scientists just say ... "Hmmm. Ok. Guess we were wrong."? Or did they go to their graves unable to accept reality? Really. You have much too high an opinion of yourselves. But then, I do too. I'm trying to work on it.

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Ok. Thanks. So should I assume that isotropy does not imply 'finite' either? If so, then how have you, or anyone else arrived at the presumption that it IS finite? Where is your actual evidence? The math? The obsevations? Or do you presume it because it sounds good to you?

...

 

Another error: the Straw Man ploy.

 

I have not claimed that space is finite. I do not assume that it is. I've said we don't know finite or infinite.

 

You impute that "presumption" and challenge me to offer evidence.

Then you sneer. "Do you presume it because it sounds good to you."

 

But I have not presumed anything. **TILT**

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How many brilliant people made similar arguments to yours when defending the steady state universe? And went to their graves unable to accept reality?

 

You have a mind set. Tsk. Tsk. Lol.

 

Could you ditch this attitude, please? This forum is intended to be for discussion, where people learn new and interesting things, not showing off that you're right and other people are wrong.

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Another error: the Straw Man ploy.

 

I have not claimed that space is finite. I do not assume that it is. I've said we don't know finite or infinite.

 

You impute that "presumption" and challenge me to offer evidence.

Then you sneer. "Do you presume it because it sounds good to you."

 

But I have not presumed anything. **TILT**

 

No sneer intended. It was a reasonable question.


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Could you ditch this attitude, please? This forum is intended to be for discussion, where people learn new and interesting things, not showing off that you're right and other people are wrong.

 

No attitude intended either. My very sincere apology for coming across that way. If you could, please just think of it as a 'passionate' attitude. Pointing out flaws that great scientists have made is just to illustrate a point. Not to belittle. Not to 'prove' I'm right, and everyone else is wrong. Having a mind set is understandable. I fight my own all the time. Sometimes emotions cloud reason, and sometimes people assume too much.

 

I wrote:

 

Is it conceiveable to you that YOUR reasoning might be flawed? I don't think it is. It certainly is conceivable to me that mine might be .....

 

How could a statement like this be construed as "I'm right and everyone else is wrong"? It does challenge, though. It wasn't intended to be a sneer by any means. Observing that 'I don't think it is' was not a baseless comment. Nor irrational. Just annoying.

 

A heated debate is not a bad thing. No one will die. Lol. As I recall, Einstein said some pretty bad things about Hubble. Galileo's peers said some bad things about him. No one likes their beliefs questioned. It's going to cause some heartburn.

 

Please don't take things personally. I will continue to do my best to remain reasonable. Again, if I am too annoying, or acting irrationally, I will understand if you choose to remove me.

 

Thanks again.

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No sneer intended. It was a reasonable question.

...

 

No, not a reasonable question. You should retract the question.

I did not assert or assume finiteness. You pretended that I did and asked me to justify something I had not claimed. You asked if I was presuming finiteness merely because it "sounded good".

 

I am offended by your misrepresentation and by the sarcastic suggestion that I would presume something without evidence because it sounded good (whatever that means).

 

You should retract the insulting question (which contains a misrepresentation) and apologize for having given offense.

 

Unless you are just trolling, you seem to suffer from a lack of information. If you want people to share facts with you, you have got to deal honestly and politely with them. If you do not, you will just be shooting yourself in the foot.

 

This may sound harsh but it is kindly meant.

 

This is what you need to start by retracting:

Ok. Thanks. So should I assume that isotropy does not imply 'finite' either? If so, then how have you, or anyone else arrived at the presumption that it IS finite? Where is your actual evidence? The math? The obsevations? Or do you presume it because it sounds good to you?
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No, not a reasonable question. You should retract the question.

I did not assert or assume finiteness. You pretended that I did and asked me to justify something I had not claimed. You asked if I was presuming finiteness merely because it "sounded good".

 

I am offended by your misrepresentation and by the sarcastic suggestion that I would presume something without evidence because it sounded good (whatever that means).

 

You should retract the insulting question (which contains a misrepresentation) and apologize for having given offense.

 

Unless you are just trolling, you seem to suffer from a lack of information. If you want people to share facts with you, you have got to deal honestly and politely with them. If you do not, you will just be shooting yourself in the foot.

 

This may sound harsh but it is kindly meant.

 

This is what you need to start by retracting:

 

I accept the rebuke. Question is retracted. I am sorry for offending you, and I understand why you were. I will try harder to tone down the passion.

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Thanks so much! I appreciate your conciliatory gesture. I will try to explain some stuff even though it is nearly midnight here (pacific time) and getting near bedtime.

 

Standard cosmology goes back to 1915-1925, Einstein's equations and then Friedman's simplification which makes the uniformity assumption you mentioned (homog and iso.) which Einstein IIRC named the "cosmological principle".

There are other names besides Friedman's (Lemaitre, Robertson Walker) and various abbreviations for the model like FRW and FRWL. But let's just call it Friedman model.

 

Matter in this model is pictured as "dust". Uniformly distributed througout all space. And mathematically space can either be finite volume or infinite volume. Space has no boundary. This was the first big bang cosmology. IIRC Friedman presented it around 1925. At first Einstein didn't like it but then he did. I forget the details. It was published (I've seen fax of the original.)

 

There are many ways that space can be finite volume and boundaryless. A simple example is the so-called 3-sphere or hypersphere. Unless you have a taste for mathematics, the details are not terribly important. A lower dimensional analog would be a 2-sphere----space being only two dimensional and having the topology of the surface of a balloon.

 

The Friedman model and the Friedman equations that govern its expansion are able to take in both the spatial finite and the spatial infinite case.

 

Both versions of the model fit the observational data extremely well. One has to make very fine measurements to tell the difference. So far our observations are not fine enough to favor one over the other. But they get better every year. Practically speaking, it turns on a certain number which can be measured using data from supernovae, galaxy counts, and the cosmic microwave background. If this number is negative, the finite case is favored. If it is zero or positive then the infinite. The number is called omega-sub-k.

 

So whether space is finite or infinite volume is actually an observational problem. It is not a question for philosophers or for amateur common sense. We actually do not know. It could go either way. We have to measure.

This year the european space agency put a craft up about one million miles from earth to make measurements of the microwave background in part to be able to determine this omega-sub-k.

 

As with much of science, when an important number is measured there is an error-bar. The error-bar we have for this number is a very small interval right around zero. As I said, it could go either way. When the european data comes in it will shrink the error-bar down some more and it could still be around zero, or it could be on the positive side, or it could be on the negative side.

 

The US NASA craft that they reported on last year and this year, with the best data so far is called WMAP.

The european craft that just started collecting data this year is called Planck.

If you find any of this puzzling please ask questions.

It's bed time for me. I'll check this tomorrow.

Edited by Martin
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Very interesting debate (except the civilities), please don't stop. I feel miserable because I belong to anothe time zone & cannot interact immediately because...sleeping.

 

A.

Martin, what is cob-webby ?

 

B.

I have the feeling neither you, me, the others, know what we are talking about. It should be preferable IMO to make some clear definitions-statements about the basic instances discussed.

Space: what is that?

1.Some propose it as "Pure Emptyness". Is "Pure Emptyness" have been observed anywhere? Is "P.E." something gigantic, or something very very small, as the "space" between elementary particles. Is P.E. the same thing some scientists call "the void" (ses below)?

2. Some propose it as the "receptacle of everything", which is a definition IMO that is coming from some kitchen rather than a laboratory, because in this case "space" looks like a casserole.BTW such expressions are used for Time as well. From the same Chef Coq is presume.

3. Some propose the "fabric of space", as if space itself was made from something. it is the point of String Theory if I am not abused:the Void. And the word 'fabric of space" is often used in trying to explain deformation of space due to gravitation in Einstein's Theories. I believe these are misleading expressions used by scientists trying to explain mathematical deformations of field lines. Lies For Children IMO.

4. Some propose space as the Universe itself. As if Matter Radiation & Space were one and the same thing, splitted in 3 different concepts. i really don't have a strong feeling about it, still wondering.

5. Some propose space as part of a Space-Time continuum (the Standard Model), where space & time are 2 entities made of the same "stuff" (?) and having interchanging capabilities. In this case, a discussion about "infinity of space" alone, without time, is completely out of sense.

6. maybe you can put a 6th or 7th definition, I ran out of ideas.

 

So, what are you talking about?

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Very interesting debate (except the civilities), please don't stop. I feel miserable because I belong to anothe time zone & cannot interact immediately because...sleeping.

 

A.

Martin, what is cob-webby ?

 

B.

I have the feeling neither you, me, the others, know what we are talking about. It should be preferable IMO to make some clear definitions-statements about the basic instances discussed.

Space: what is that?

1.Some propose it as "Pure Emptyness". Is "Pure Emptyness" have been observed anywhere? Is "P.E." something gigantic, or something very very small, as the "space" between elementary particles. Is P.E. the same thing some scientists call "the void" (ses below)?

2. Some propose it as the "receptacle of everything", which is a definition IMO that is coming from some kitchen rather than a laboratory, because in this case "space" looks like a casserole.BTW such expressions are used for Time as well. From the same Chef Coq is presume.

3. Some propose the "fabric of space", as if space itself was made from something. it is the point of String Theory if I am not abused:the Void. And the word 'fabric of space" is often used in trying to explain deformation of space due to gravitation in Einstein's Theories. I believe these are misleading expressions used by scientists trying to explain mathematical deformations of field lines. Lies For Children IMO.

4. Some propose space as the Universe itself. As if Matter Radiation & Space were one and the same thing, splitted in 3 different concepts. i really don't have a strong feeling about it, still wondering.

5. Some propose space as part of a Space-Time continuum (the Standard Model), where space & time are 2 entities made of the same "stuff" (?) and having interchanging capabilities. In this case, a discussion about "infinity of space" alone, without time, is completely out of sense.

6. maybe you can put a 6th or 7th definition, I ran out of ideas.

 

So, what are you talking about?

 

Very salient questions Michael. I need to stress once again, that I am not a 'proponent' per se of infinite space. I am just looking, to the best of my ability, at all the facts. The 'proven' math. The corroboraing experiments, and the observations. This 'leans' me toward infinity. There is no evidence that I am aware of to pull me over to the other side. If there were some, I would be happy to reassess my 'working model'.

 

There is nothing to make me believe that the space our universe occupies is somehow unique to our location, or that the properties exhibited are not universal. And universal means ... infinite. Until proven NOT to be infinite.

 

Martin is correct when he says that he did not personally presume anything. I made that presumption for him, based on his 'blue ribbon' comments. Strictly speaking, science won't go out on a limb and declare space finite, or infinite. But the closed model has become entrenched in 'our' thinking. So virtually all models ( theoretical, of course ) depict a finite universe. I am fighting a difficult battle ... but not one that I wasn't expecting, especially considering my backround.

 

#3 would be the way I would start to describe it. Sort of. Strings may or may not exist. But I think a good case can be made for space to 'be' energy, rather than 'nothing' with some force acting upon it.

 

I have no evidence that time did not exist before our local universe, and certainly time operates here in a linear fashion ... so what ( somewhat meager, I suppose ) evidence I have would lean toward time always existing. So let's include #5.

 

I call it the fabric of space for better visualization, but really, it's just appears to be a property that space has.

 

I don't believe there is any evidence in our local area that a complete void exists. An 'absolute' vacuum, devoid of matter, OR energy. So let's include #4, too. But let's say that matter and radiation are simply different manifestations of space's inherent energy. Energy can neither be created, nor destroyed, and the matter and radiation had to come from somewhere. Space's ( possible ) energy stores seem like the likeliest place to start looking. As opposed to other dimensions, metaphysical solutions, or just 'came out of nowhere'.

 

Of course we need to keep our minds open to other solutions ... even if they seem a little off the wall at first glance. We need to continue to explore strings, and whatever other possibilities bright scientists come up with. Negative results is just as good as positive results. We still learn. In most cases we learn more by the negative results.

Edited by pywakit
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Very interesting debate (except the civilities), please don't stop. I feel miserable because I belong to anothe time zone & cannot interact immediately because...sleeping.

 

A.

Martin, what is cob-webby ?

 

 

I think he means filamentous like a spiders web...think of lots of dusty spiders webs. Found some great computer simulations here of the Universe in all its cobwebby glory! :):

 

http://cosmicweb.uchicago.edu/filaments.html

 

The other simulations at the smaller scale look nice too.

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Thanks so much! I appreciate your conciliatory gesture. I will try to explain some stuff even though it is nearly midnight here (pacific time) and getting near bedtime.

 

Standard cosmology goes back to 1915-1925, Einstein's equations and then Friedman's simplification which makes the uniformity assumption you mentioned (homog and iso.) which Einstein IIRC named the "cosmological principle".

There are other names besides Friedman's (Lemaitre, Robertson Walker) and various abbreviations for the model like FRW and FRWL. But let's just call it Friedman model.

 

Matter in this model is pictured as "dust". Uniformly distributed througout all space. And mathematically space can either be finite volume or infinite volume. Space has no boundary. This was the first big bang cosmology. IIRC Friedman presented it around 1925. At first Einstein didn't like it but then he did. I forget the details. It was published (I've seen fax of the original.)

 

There are many ways that space can be finite volume and boundaryless. A simple example is the so-called 3-sphere or hypersphere. Unless you have a taste for mathematics, the details are not terribly important. A lower dimensional analog would be a 2-sphere----space being only two dimensional and having the topology of the surface of a balloon.

 

The Friedman model and the Friedman equations that govern its expansion are able to take in both the spatial finite and the spatial infinite case.

 

Both versions of the model fit the observational data extremely well. One has to make very fine measurements to tell the difference. So far our observations are not fine enough to favor one over the other. But they get better every year. Practically speaking, it turns on a certain number which can be measured using data from supernovae, galaxy counts, and the cosmic microwave background. If this number is negative, the finite case is favored. If it is zero or positive then the infinite. The number is called omega-sub-k.

 

So whether space is finite or infinite volume is actually an observational problem. It is not a question for philosophers or for amateur common sense. We actually do not know. It could go either way. We have to measure.

This year the european space agency put a craft up about one million miles from earth to make measurements of the microwave background in part to be able to determine this omega-sub-k.

 

As with much of science, when an important number is measured there is an error-bar. The error-bar we have for this number is a very small interval right around zero. As I said, it could go either way. When the european data comes in it will shrink the error-bar down some more and it could still be around zero, or it could be on the positive side, or it could be on the negative side.

 

The US NASA craft that they reported on last year and this year, with the best data so far is called WMAP.

The european craft that just started collecting data this year is called Planck.

If you find any of this puzzling please ask questions.

It's bed time for me. I'll check this tomorrow.

 

And thank you for forgiving me ...

 

No, not puzzling at all. We really are not in much disagreement here. I have no ability to do the math myself, but no problem visualizing the various models. I was dimly aware ( lol ) that that the math allowed for finite or infinite. At the time the cosmological principle was proposed, we could see ( guessing here ) 1/1000th of space we can see now. Maybe 1/10,000th. Or less. You are so right in that this is an observational problem. Comparatively speaking, we were 'blind' at the time of Einstein's, and Friedman's work.

 

I have studied a little of the WMAP data, and I try to keep abreast of the latest developments. Cosmology incorporates several disciplines, and I am just grateful that I did not have to immerse myself in one at the expense of the rest. There is a great deal of information available, and it all is part of the larger puzzle.

 

I can appreciate the 'purist' logic here. I understand that the numbers still allow for either side to 'win'. I don't agree, partly because of my ( admittedly limited ) knowledge of space, and that pesky un-scientific common sense ... which has also served well in many discoveries throughout history ... plus, I suppose my ability to comprehend infinity ( imagined or not ), and my inability to comprehend finite space. Guess I have my own 'mind set'. As I already confessed to. We both know that 100 scientists can look at the same evidence and come up with 100 different interpretations. I think this is one of our greatest strengths. "Leave no stone unturned".

 

I am very excited to be living at this time in history. We ARE going to answer this question ... at least, to 'a reasoned conclusion' very soon. I am quite confident it will come down on the side of infinity.

 

Hope I'm right.

 

And thank you again. I am kind of obnoxious at times, aren't I?


Merged post follows:

Consecutive posts merged
I think he means filamentous like a spiders web...think of lots of dusty spiders webs. Found some great computer simulations here of the Universe in all its cobwebby glory! :):

 

http://cosmicweb.uchicago.edu/filaments.html

 

The other simulations at the smaller scale look nice too.

 

I'm thinking Michael was being facetious.

Edited by pywakit
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I think he means filamentous like a spiders web...think of lots of dusty spiders webs. Found some great computer simulations here of the Universe in all its cobwebby glory! :):

 

http://cosmicweb.uchicago.edu/filaments.html

 

The other simulations at the smaller scale look nice too.

 

Thank you for the link. The little video is very impressive

http://cosmicweb.uchicago.edu/images/mov/bnr_half4.mpg

....and completely counter intuitive (except for the Chef-Coq mentionned above, who would see it as a missed receipe for vinaigrette) Like the expansion of a gas backwards. Organization from chaos. Negative entropy?

Edited by michel123456
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