ChatterBank3 mins ago
Infinite Or Closed Universe
Can any of the scientific minds here please tell me what the current scientific understanding of the universe is at the present? (or at least the general consensus). Is it closed or infinite?
I have trouble wrapping my head around either model. Is there another one that I havnt heard about.
Thanks.
I have trouble wrapping my head around either model. Is there another one that I havnt heard about.
Thanks.
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If maggiebee asked Stephen Hawking what was outside the Universe he would probably indeed reply, if pressed enough, "I don't know". If, on the other hand, maggiebee asked Hawing (or me, for that matter) what is outside a four-dimensional compact Lorentzian Manifold, then he would be able to answer confidently, with absolute certainty, "nothing, unless there is a manifold of higher dimension in which the 4-manifold exists".
At this point perhaps you would be no further forward, but there you go. In fact this is what my posts (and Kidas's) are trying to describe, with perhaps limited success. But, to be fair, it is very difficult indeed to describe such complicated mathematical structures without using any of the actual mathematics at all. And, even with those terms to hand (and, as I have expressed elsewhere, I am very far from an expert on the mathematics of General Relativity), it's very hard to picture it properly myself.
But the point I am ultimately hoping to make is that, while indeed the answer is, ultimately, that we don't know, at least these days we are getting closer and closer to knowing what the right question is.
At this point perhaps you would be no further forward, but there you go. In fact this is what my posts (and Kidas's) are trying to describe, with perhaps limited success. But, to be fair, it is very difficult indeed to describe such complicated mathematical structures without using any of the actual mathematics at all. And, even with those terms to hand (and, as I have expressed elsewhere, I am very far from an expert on the mathematics of General Relativity), it's very hard to picture it properly myself.
But the point I am ultimately hoping to make is that, while indeed the answer is, ultimately, that we don't know, at least these days we are getting closer and closer to knowing what the right question is.
Jim, //then he would be able to answer confidently, with absolute certainty, "nothing, //
… to which I would be tempted to ask ‘What is ‘nothing?’’
//unless there is a manifold of higher dimension in which the 4-manifold exists".//
.. which means he doesn’t know.
Ultimately no one knows - but it's good to hypothesise.
… to which I would be tempted to ask ‘What is ‘nothing?’’
//unless there is a manifold of higher dimension in which the 4-manifold exists".//
.. which means he doesn’t know.
Ultimately no one knows - but it's good to hypothesise.
You're confusing two questions there Naomi. One is a physical question, the other is a mathematical one. About the mathematics it's perfectly possible to answer the question with absolute certainty, as I did so. Physically, one can pose possibilities and attempt to distinguish one from the other by observations without ever knowing for certain what is right or what is not, but the absolutely certain, mathematical, answer, is that nothing is outside a manifold with the properties I stated, because there is literally no such thing as an outside, and nowhere for it to be -- unless, as I said, one invokes a fifth (or further) higher dimensions to create the necessary space.
Is there literally nothing outside the universe, or are there wonders if which we may never be truly aware, hidden away in higher dimensions? I don't know. But I *do* know something about what either of these possibilities might look like, and how we might go about describing them.
Is there literally nothing outside the universe, or are there wonders if which we may never be truly aware, hidden away in higher dimensions? I don't know. But I *do* know something about what either of these possibilities might look like, and how we might go about describing them.
//what is outside a four-dimensional compact Lorentzian Manifold, then //
hahaha! I deliberately tried to avoid the word manifold, but yep - that's exactly what we're dealing with.
Just believe Jim - he knows.
In the end, one can read (or write) as much pop science as one wants, but without the maths, all explanations are going to be inadequate.
And yes, the math is Riemann space; Lorentzian manifolds; 4th-order tensors and differential equations. It's far from easy.
Sorry, but in the end one can only convey so much in words.
hahaha! I deliberately tried to avoid the word manifold, but yep - that's exactly what we're dealing with.
Just believe Jim - he knows.
In the end, one can read (or write) as much pop science as one wants, but without the maths, all explanations are going to be inadequate.
And yes, the math is Riemann space; Lorentzian manifolds; 4th-order tensors and differential equations. It's far from easy.
Sorry, but in the end one can only convey so much in words.
On the other hand, mathematics remains the best language we have developed to try and understand it, and it appears to be remarkably successful. It's a wonder that it works at all, but it does seem to do an extraordinarily good job. While a mathematical description and the physical reality will never perfectly align, they are often so close that your best route to trying to understand the physics -- and then, possibly, to extend that understanding -- is by trying to understand the related mathematics.
Jim, indeed, but I wonder if such confidence may ultimately prove restrictive? As I’ve told you before I detect a distinct lack of curiosity in those who depend entirely upon the sciences for their answers which is why I like to hear ideas, however seemingly bizarre, from minds that are capable of stretching beyond the confines of mathematics. I can’t help thinking that discovery of what’s really out there may well not only blow our socks off, but will blow our confidence in the accuracy of science as we now know it right into space!
It seems like, almost by definition, you'd judge me one of the least qualified people able to comment on that, but all I can say is that the current approach to understanding the Universe is far from exhausted yet, so it's surely very premature to worry about whether or not it's too restrictive in the long run.
It was, anyway, the very curiosity you seem to think that I am lacking in that led me to take up the subject as a serious and, currently, full-time career. But there you are.
It was, anyway, the very curiosity you seem to think that I am lacking in that led me to take up the subject as a serious and, currently, full-time career. But there you are.
Jim, //it's surely very premature to worry about whether or not it's too restrictive in the long run.//
That’s exactly what I’m talking about. Don’t think any further than you have to right now! That attitude is restrictive and smacks to me of a distinct lack of curiosity. I'll just say I’ve no doubt that you’re a very capable mathematician.
That’s exactly what I’m talking about. Don’t think any further than you have to right now! That attitude is restrictive and smacks to me of a distinct lack of curiosity. I'll just say I’ve no doubt that you’re a very capable mathematician.
That seems to be misinterpreting my point. I'm saying that we are nowhere near the limits of what we can achieve -- a point I know that you agree with. We just have wildly different ideas about what comes next, and how to make progress.
I'm never going to be one of the world's great scientists. Still, before I quit this world I will have played some small part in moving the subject forward, so that at least -- my own, small, contribution to scientific progress -- is something I can be proud of.
I'm never going to be one of the world's great scientists. Still, before I quit this world I will have played some small part in moving the subject forward, so that at least -- my own, small, contribution to scientific progress -- is something I can be proud of.
Hi Naomi
You’re right. But if I might venture to add something more: it takes all sorts.
I think many scientists would admire people like you for eloquence, creativity, imagination and other wonderful characteristics.
When you see TV debates between politicians and scientists (or even poets and scientists) the scientists routinely lose. Because the scientists argue based on their common understanding of the ‘rules’ of science.
Poets, historians, politicians and lawyers argue through persuasion, emotion, passion and selective choice of their evidence.
It’s much more effective than the scientists’ approach. If Jim and I were to argue about some aspect of the above, he would demolish my arguments with ease by pointing out that I had done some of my vector analysis incorrectly. That takes skill and knowledge, but it is not in the least flashy or exciting. As soon as he pointed out my error, I’d have to acquiesce, because in that environment, there is no persuasion or emotion that can cover up for my mistake.
You’re quite right to expose the weaknesses of some scientists as lacking imagination. But I’d argue that many people can have limited imaginations. There are people who blindly follow the rules in all walks of life: teachers; doctors; politicians. I’m not sure scientists are more guilty of that than any other group. I can think of politicians who are committed to certain views and no amount of evidence, or passion or persuasive argument will convince them that they are utterly, totally wrong. They simply continue to assert their long-held views without listening to the counter-arguments.
I'll definitely agree with you that open-mindedness is something to strive for.
You’re right. But if I might venture to add something more: it takes all sorts.
I think many scientists would admire people like you for eloquence, creativity, imagination and other wonderful characteristics.
When you see TV debates between politicians and scientists (or even poets and scientists) the scientists routinely lose. Because the scientists argue based on their common understanding of the ‘rules’ of science.
Poets, historians, politicians and lawyers argue through persuasion, emotion, passion and selective choice of their evidence.
It’s much more effective than the scientists’ approach. If Jim and I were to argue about some aspect of the above, he would demolish my arguments with ease by pointing out that I had done some of my vector analysis incorrectly. That takes skill and knowledge, but it is not in the least flashy or exciting. As soon as he pointed out my error, I’d have to acquiesce, because in that environment, there is no persuasion or emotion that can cover up for my mistake.
You’re quite right to expose the weaknesses of some scientists as lacking imagination. But I’d argue that many people can have limited imaginations. There are people who blindly follow the rules in all walks of life: teachers; doctors; politicians. I’m not sure scientists are more guilty of that than any other group. I can think of politicians who are committed to certain views and no amount of evidence, or passion or persuasive argument will convince them that they are utterly, totally wrong. They simply continue to assert their long-held views without listening to the counter-arguments.
I'll definitely agree with you that open-mindedness is something to strive for.
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