a little help needed for an ignorant old man

[CraigS]

Originally Posted by Brian W

Hi Craig you have just hit upon my dilemma.

(1) all of my observations tell me that any three dimensional object has a centre.

(2) my observations tell me the universe is three dimensional.

(3) therefore the universe must have a centre.

The above is nothing more or less than basic logic and as such cannot be denied. However as it is a tautology it does not of necessity about reality.

I suppose that I am having the same type of problem that someone who is working on a unified theory faces; how do you make the micro and the macro make sense together?

Oh well, as you say Craig one can only keep on keeping on.

Brian

Hi Brian;

Don't give up there, fella ! (Good to have you around !)

Glad to see Steven's words on this, also.

Hubble's Law is a kind of set in stone in astronomy circles.
It'd be a real nightmare to try and explain his observations in any other way!
Others have tried and some of the stuff they come up with from thereon looks positively screwy !

Let us know your thoughts.

Cheers and Regards

[mswhin63 (Malcolm)]

I suppose it will be difficult to locate the centre of the universe (the point equal-distant from the outer edge/s) until we actually see the edge of the universe. I understand the principle of the observer as the centre but that is the centre of observation not the centre of physical reality.

I always though maths was used to describe what we see not what we can't see. I suppose I got it all wrong. I watched the BBC - "Dangerous Knowledge" program and I suppose they died from trying to work out what they couldn't see, although they did live in difficult times. So yes we need to be careful with math.

[Alchemy (Clive)]

I see where you are coming from Brian. The universe is 3 dimensional from our perspective and logic does dictate a centre, the problem is that because space is expanding it's indeterminable.

Ie.... If for example the centre of the universe was the Virgo cluster of galaxies you might argue it's not moving...... But we being off centre are, and the clusters 180 degrees opposite are expanding outwards from us also, the end result is both sides APEAR to be moving at the same rates. So should as logic dictates... a centre..... You can never find it.

[sjastro]

Originally Posted by mswhin63

I suppose it will be difficult to locate the centre of the universe (the point equal-distant from the outer edge/s) until we actually see the edge of the universe. I understand the principle of the observer as the centre but that is the centre of observation not the centre of physical reality.

The Universe doesn't have a physical centre for the reasons I gave in my previous post. Neither does the Universe have an edge, the implications for that would be expansion into existing space. In other words metric expansion of space wouldn't occur and we wouldn't be able to explain Hubble's Law or the mechanism of cosmological redshift.

I always though maths was used to describe what we see not what we can't see. I suppose I got it all wrong. I watched the BBC - "Dangerous Knowledge" program and I suppose they died from trying to work out what they couldn't see, although they did live in difficult times. So yes we need to be careful with math.

These guys worked in the field of pure mathematics. Pure mathematicians consider themselves artists, and probably had all the attributes of artistic temperment.
http://en.wikipedia.org/wiki/Mathematical_beauty

Not surprising some of them went the way they did.

Others went in more spectacular ways.
This kid died at the age of twenty, his ideas in mathematics were so advanced they were used in physics 120 years after his death.

http://en.wikipedia.org/wiki/%C3%89variste_Galois

Regards

Steven

[Steffen]

I reckon some of the confusion stems from the use of the term "centre". You can of course define any number of "centres" in a 3-dimensional space, such as centre of gravity, or geometrical centre, or centre of interest

What doesn't have a centre (or point of origin) though is the expansion of the universe. Wherever you stand in the universe things are moving away from you as if you where right at the point of origin of the expansion. Any spot is as good (and as "central") as the next one.

Cheers
Steffen.

[CraigS]

Here's a thought .. perhaps what we're saying here, is that from today's observations, it is not possible establish a geometric centre of the universe.

This doesn't mean that at the instant of the Big Bang, the universe didn't have a geometric centre. After all, the theory points out that it was very small. However, all of the text I've read is also very careful to point out that we still don't understand much about the very early phases of the universe.

I think Brian may have already mentioned this, also.

So, it would only be speculation to talk about when the universe may, (or may not), have had a geometric centre. But it may have been possible, maybe even probable .. who knows ?

I have read that they have shown that it is possible that things may have been very chaotic in the very early stages (blue & red shifts randomly distributed).

Following this rationale, the points Brian is making seem reasonable.

Comments welcome .. this discussion, (being a different one to where I was coming from originally), however, is all very speculative.

Cheers

[Archy (George)]

Originally Posted by CraigS

Care to elaborate on where the "fiction" is ?

Cheers

Where is the Science

[CraigS]

Originally Posted by Archy

Where is the Science

What is your definition of Science ?

[Archy (George)]

Originally Posted by CraigS

What is your definition of Science ?

I don't need to have a definition of science: Popper did it for me. If you don't understand my reference, give me your definition of science.

[The_Cat (Jeremy)]

Originally Posted by sjastro

The Universe doesn't have a physical centre for the reasons I gave in my previous post. Neither does the Universe have an edge, the implications for that would be expansion into existing space. In other words metric expansion of space wouldn't occur and we wouldn't be able to explain Hubble's Law or the mechanism of cosmological redshift.



These guys worked in the field of pure mathematics. Pure mathematicians consider themselves artists, and probably had all the attributes of artistic temperment.
http://en.wikipedia.org/wiki/Mathematical_beauty

Not surprising some of them went the way they did.

Others went in more spectacular ways.
This kid died at the age of twenty, his ideas in mathematics were so advanced they were used in physics 120 years after his death.

http://en.wikipedia.org/wiki/%C3%89variste_Galois

Regards

Steven

I don't know too many pure mathematicians who consider themselves artists !!

Re: Use of Galois fields (ie. finite field arithmetic) in physics ? Where ?

We use these in the design of error control codes - our CD players would not work without them !!

Jeremy

[OICURMT]

Originally Posted by sjastro

The danger with any analogy is that while it may aid in visualization, taken literally it can lead to false conclusions. One needs to be very careful visualizing mathematical concepts.


Regards

Steven

An oh-so-true statement. In Petroleum Engineering, we often calculate hydraulic tables as a 6-dimensional matrix. The maths are accurate, but trying to show an executive the results can leave them pondering for days if they don't have an engineering background.

Trying to display the results is equally challenging, as people are used to 3 dimensions (x,y,z). We augment the display via color (4th), saturation (5th) and transparency (6th).

OIC!

[sjastro]

Originally Posted by The_Cat

I don't know too many pure mathematicians who consider themselves artists !!

Re: Use of Galois fields (ie. finite field arithmetic) in physics ? Where ?

We use these in the design of error control codes - our CD players would not work without them !!

Jeremy

I did pure maths as an undergraduate before switching over to applied maths.
Pure mathematicians see beauty in their work based on the originality, simplicity and logic, somewhat like an art form, the applied mathematician is far more phelgmatic.

I found pure maths excruciatingly boring, abstract and difficult, I think you need to be passionate to succeed.

Sorry the sample size is small but it is based on personal observations.

Galois made significant contributions to Group Theory. Group theory is used extensively in particle physics.

Regards

Steven

[Brian W (Brian)]

Originally Posted by sjastro

T

Hubble's law is explained by having the receding galaxies fixed in space and allowing the space to expand. Hence galaxies recede as a function of the increasing scale of the Universe. In this scenario there is no absolute centre, each observer in the Universe can rightly claim to be the centre.

This leads to the cosmological principle as explained by Craig.

Regards

Steven

Now this begins to become understandable. with 'space expanding' and galaxies more or less going along for the ride then I can begin to see where no 'absolute centre' makes sense.

Now a little more help if you please... is it permissible or sensible might be a better word, to talk of an' absolute beginning position'? Granted that it is not the absolute centre.
Brian

[sjastro]

Originally Posted by Brian W

Now this begins to become understandable. with 'space expanding' and galaxies more or less going along for the ride then I can begin to see where no 'absolute centre' makes sense.

Now a little more help if you please... is it permissible or sensible might be a better word, to talk of an' absolute beginning position'? Granted that it is not the absolute centre.
Brian

Hello Brian,

Let's "look" at a very small object such as an electron. If we had the capability of observing electrons, the electrons would not appear as tiny spheres or points but as a "cloud" structure. This is quantum mechanics at work at small scales. The "cloud" represents the probability of finding the electron in a small region of space. It's impossible to pinpoint the exact position of the electron in space.

In the very early history of the Universe, the scale was small enough for the Universe to obey the laws of Quantum mechanics. For the same reasons as the electron, the beginning position would have been spread out over a small but finite volume of space instead of occupying a point in space time.
As the Universe expands so does this small finite volume of space, so it impossible to even define the region in which this beginning position could have occurred.

Regards

Steven

[CraigS]

It seems that it is hypothesised that even before the Universe obeyed the laws of quantum mechanics, space and time 'break down', which suggests that they may be approximations of something more fundamental.

At this time, it seems that dimensions wouldn't make any sense (nor units of time).

Interesting.

Cheers

[Archy (George)]

Originally Posted by sjastro

Hello Brian,

Let's "look" at a very small object such as an electron. If we had the capability of observing electrons, the electrons would not appear as tiny spheres or points but as a "cloud" structure. This is quantum mechanics at work at small scales. The "cloud" represents the probability of finding the electron in a small region of space. It's impossible to pinpoint the exact position of the electron in space.

In the very early history of the Universe, the scale was small enough for the Universe to obey the laws of Quantum mechanics. For the same reasons as the electron, the beginning position would have been spread out over a small but finite volume of space instead of occupying a point in space time.
As the Universe expands so does this small finite volume of space, so it impossible to even define the region in which this beginning position could have occurred.

Regards

Steven

How do you know?

[SkyViking (Rolf)]

Originally Posted by Brian W

Now this begins to become understandable. with 'space expanding' and galaxies more or less going along for the ride then I can begin to see where no 'absolute centre' makes sense.

Now a little more help if you please... is it permissible or sensible might be a better word, to talk of an' absolute beginning position'? Granted that it is not the absolute centre.
Brian

I suppose the quite intuitive reasoning behind the original question is that the Big Bang was an explosion (as it is all too often depicted as) and therefore it must have had a centre, or merely that the Big Bang must have happened at a particular point in the Universe. The key point however is that everything, both space and time - essentially what we call the Universe - was created in the Big Bang, and thus it is impossible to define a position inside the resulting Universe for this event.

For example, imagine a new coordinate system that suddenly emerges and expands from a single point. That single point can only be defined relative to some other coordinate system, which must be outside the expanding one.
Likewise, any 'centre', 'beginning position', 'point of origin' (or what one might call it) for the Universe would have to be relative to something else that is outside the Universe itself. But what, if anything, which may or may not exist outside the Universe is of course pure speculation...

[Brian W (Brian)]

Hi all, seems to me that all of this hangs upon the idea that the universe is finite. By this I mean that there is a beginning and an ending. As most of us have been directly influenced by the Judeo / Christian way of looking at things this is quite understandable. (please note that I am not bringing G-d into the equation just the idea that our culture limits the questions we can ask)

How would the questions and answers be effected, or indeed would they be, if we were to approach this from the cultural belief that the universe is infinite with no beginning and no ending?

If the big bang was simply the continuation of what came before... and in time what was started would move into what comes next?

Brian

[CraigS]

Originally Posted by Brian W

Hi all, seems to me that all of this hangs upon the idea that the universe is finite. By this I mean that there is a beginning and an ending. As most of us have been directly influenced by the Judeo / Christian way of looking at things this is quite understandable. (please note that I am not bringing G-d into the equation just the idea that our culture limits the questions we can ask)

How would the questions and answers be effected, or indeed would they be, if we were to approach this from the cultural belief that the universe is infinite with no beginning and no ending?

If the big bang was simply the continuation of what came before... and in time what was started would move into what comes next?

Brian

Brian;

This conversation has now drifted into philosophical areas, (which is OK .. and normal .. most threads in the Science Forum end up this way).

My 2 cents worth on this is that I have no problems in thinking of the Universe as infinite, with no beginning and no ending. Neither have many other prominent scientists throughout history (Einstein, Fred Hoyle, etc, etc). Their ideas in these areas however, have tended to fall by the wayside in the light of hard data. They do make various reappearances in man-made hypotheses/theories which to a certain degree, contain some measure of 'consensus' or 'agreement'.

Such thoughts are as good as anything for having some kind of picture in one's mind about it all. At the end of the day, they are mostly opinions and as they say .. 'everybody's got one .. and they rarely make a big difference'. Big shifts mostly tend to happen upon observation of 'anomalous' phenomena.

As far as cultural influences on scientific thinking goes, many famous scientists also have had in the past, religious beliefs. We have discussed the Jesuit Scientists previously, as an example. Another example is that the Pope also recognises the very scientists behind the mainstream thinking outlined in the response posts in this thread. This would seem to be evidence of sociological religious support for mainstream scientific thinking.

The main point I'd like to make from what you say is that modern science doesn't seek the 'truth'. Its about observing, theorising, seeking evidence, falsifying and refining then predicting. This is all about decoupling the false perceptions which humans generate from looking at the environment around us, from the cold reality of the physical world.

This approach has also culminated in a modern perspective which leans towards creation of the universe from nothing, with purely unthinking physical processes building what we see around us. I for one, have no problems living inside any of these dimensions of thought.

How about you ?

Cheers and Regards

[Brian W (Brian)]

Hi Craig, apparently I do have problems with living inside some of these paradigms, else why would I be in this conversation?

One of the main beliefs in science is that energy can be neither created nor destroyed but simply changed. That being the case how does one get creation of the universe out of nothing.

That seems to break a very basic 'law'.

Brian