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Nigel G

Is our Universe 13.7 billion years old ? I'm not quite convinced

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15 minutes ago, Nigel G said:

this trip is to bring the yacht back

confused than me

You must have been ! how did you manage to leave a yacht behind, I blame that Jura nectar :) !

Last time I was on the (not so) high seas was in a Mirror dingy

31 minutes ago, DRT said:

The Singleton?

I worked with a Valerie of that ilk and badge, a long time ago.

(oops, lost a quote ! ) Thanks for the Kerr ref. it deffo says a ring singularity !!! my head hurts, I'll try again tomorrow !

 

Edited by SilverAstro
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Warning to travelers!
Everything that has been said here is purely theoretical. The Kerr solution is very unstable, corresponding as it does to a black hole in complete isolation. The addition of extraneous matter, such as even the approach of a would-be traveler, could be enough to destabilize the Kerr solution and make travel through the black hole unrealistic. To properly investigate the feasibility of journeys past or through the singularities of black holes we need to be able to take quantum effects into  account  the Enterprise for a spin. However, this will require a  quantum theory of gravity   permission from starfleet. – one of the chief goals of contemporary theoretical physics. 

It's starting to make sense 

 

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On 7/9/2016 at 23:33, Nigel G said:

Warning to travelers!
Everything that has been said here is purely theoretical. The Kerr solution is very unstable, corresponding as it does to a black hole in complete isolation. The addition of extraneous matter, such as even the approach of a would-be traveler, could be enough to destabilize the Kerr solution and make travel through the black hole unrealistic. To properly investigate the feasibility of journeys past or through the singularities of black holes we need to be able to take quantum effects into  account  the Enterprise for a spin. However, this will require a  quantum theory of gravity   permission from starfleet. – one of the chief goals of contemporary theoretical physics. 

It's starting to make sense 

So is that like the Riker Manoeuvre then?

I'll get my coat.

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This all started so well, I see the whisky is kicking in then gents?

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The OP's argument seems to be if two runners leave a house and run in opposite directions for an hour, they will end up two hours away from each other. This is logical. What the OP seems to then conclude is that the two runners left the house two hours before hand, which is clearly not the case.

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The main confusion with the expansion of the universe is the use of velocity in the expansion term. I wonder if the term was rewritten as distance/distance/time if some of the confusion would disappear.

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I'd like to pay Stephen Hawking the simplest of courtesies by spelling his name correctly.

 

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Is not everything we see or hear or learn or sense or feel or experience or accept etc down to perception, comprehension limits, bias, needs, desires, and anything and everything else that is viewer based ?

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12 minutes ago, Pippy said:

Is not everything we see or hear or learn or sense or feel or experience or accept etc down to perception, comprehension limits, bias, needs, desires, and anything and everything else that is viewer based ?

Probably, though mathematics might be exempt. However, there exists a hierachy of credibilty in the world of ideas. To regard astrology and astronomy, for instance, as equally valid or invalid would be to fail to take cognizance of this hierarchy. In science the assertions of one person or group count for nothing. These assertions must have evidence in their favour, evidence which can be re-detected afresh by other people. It is reassuring to note that, on occasion, the conclusions of science have seemed particularly unreasonable to us. (The moving earth, the fossil record, the relativity of time and space, the oddities of quantum theory.) This is healthy because it suggests that we are not creating a model of the world out of what seems reasonable to us but rather that we are willing to believe the remarkable discoveries we make when we place all possible constraints on our assumptions.

But is there a reality without us and our perceptions? I don't think we know, but knowing that we don't know is interesting and a start... (Personally I suspect that there will be something out there without us but that it might be so chaotic as to be incomprehensible, possibly to all or any observer however able. The structured 'reality' that we see and study may simply arise from the way we are constrained to interact with a chaotic 'outside reality.')

Olly

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10 minutes ago, ollypenrice said:

Probably, though mathematics might be exempt. However, there exists a hierachy of credibilty in the world of ideas. To regard astrology and astronomy, for instance, as equally valid or invalid would be to fail to take cognizance of this hierarchy. In science the assertions of one person or group count for nothing. These assertions must have evidence in their favour, evidence which can be re-detected afresh by other people. It is reassuring to note that, on occasion, the conclusions of science have seemed particularly unreasonable to us. (The moving earth, the fossil record, the relativity of time and space, the oddities of quantum theory.) This is healthy because it suggests that we are not creating a model of the world out of what seems reasonable to us but rather that we are willing to believe the remarkable discoveries we make when we place all possible constraints on our assumptions.

But is there a reality without us and our perceptions? I don't think we know, but knowing that we don't know is interesting and a start... (Personally I suspect that there will be something out there without us but that it might be so chaotic as to be incomprehensible, possibly to all or any observer however able. The structured 'reality' that we see and study may simply arise from the way we are constrained to interact with a chaotic 'outside reality.')

I'm really not a follower of belief systems, mainly appliable/testable science (assuming science is not based on belief). Whether such bias will lead to our survival or not is another matter entirely, I guess.

Maybe our human inbuilt thought processes and imagination/imaging system is very much the same throughout each and every one of us ? .. if so, then what we call "repeatability" (in all it's percetual/physical forms) can't be relied upon ?  maybe it just means that what one person generally sees/feels/experiences will also be generally seen/felt/experienced by most others is very much the same way, hence repeatability ?

 

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2 hours ago, ollypenrice said:

But is there a reality without us and our perceptions? I don't think we know, but knowing that we don't know is interesting and a start...

It depends, I think, on what you mean by reality. I believe there is a physical "reality" independent of human existence in the sense that any other self aware beings could perceive it. They may not perceive as we do but I think the scientific models they would develop to describe it would be mathematically analogues to ours. ( In the sense that our different formulations of QM are the same.) I would also conjecture that it can't be too chaotic for us and the universe we observe to have evolved.

Regards Andrew

 

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15 minutes ago, andrew s said:

It depends, I think, on what you mean by reality. I believe there is a physical "reality" independent of human existence in the sense that any other self aware beings could perceive it. They may not perceive as we do but I think the scientific models they would develop to describe it would be mathematically analogues to ours. ( In the sense that our different formulations of QM are the same.) I would also conjecture that it can't be too chaotic for us and the universe we observe to have evolved.

Regards Andrew

 

My point is that what may have evolved in our case is a systematic perception of the universe. Different observers might, conceivably, have evolved entirely different perceptions. The underlying universe might be the same. Imagine a square matrix of 1000 dots. You can 'join the dots' to make an assortment of images. Each of these images is valid, in the sense that each is viable within the 1000 dot matrix. Make that a million dot matrix. Then make it three dimensional. Than make it more than three dimensional. By now the matrix is essentially chaotic (structureless) but, still, dots can be joined by dot-joiners. Is it impossible that what we really really do is join dots? The argument against this is that we are many (or most of us think we are) but it could be that something we have in common, as yet unidentified, causes us to join the same dots? I'm not a solipsist. I believe other people do exist. They might not, I might be the only sentient being in the universe, but if I thought that I would not be bothering to talk to 'you' now!! I would just get drunk. Why bother to think when anything you think is true? If you did that you would be Donald Trump.

Olly

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On 08/07/2016 at 22:48, Nigel G said:

...

surely that makes our Universe at least 26 billion years old ?...

 

Mad, but... by the time light reached us from its origin 13 billion years ago, the object that emitted it has aged 13 billion years, so...

13 + 13 = 26bn.

I'll get me coat.

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1 hour ago, ollypenrice said:

Imagine a square matrix of 1000 dots. You can 'join the dots' to make an assortment of images. Each of these images is valid, in the sense that each is viable within the 1000 dot matrix

I am not sure I full or even partially understand what point you are making with this analogy. However, I don't believe we are free to join the dots as we wish but that reality limits and constrains the allowable patterns and that these constraints apply to all "observers".  In this sense it is not chaotic in my view.

But, as I sat Olly I am probably missing your point.

Regards Andrew

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3 hours ago, andrew s said:

However, I don't believe we are free to join the dots as we wish but that reality limits and constrains the allowable patterns and that these constraints apply to all "observers".  In this sense it is not chaotic in my view.

I'm more inclined to think that we are in no position at all to be telling the universe how it must be, what rules it must follow etc. I tend to think we like to see and experience our lives with some level of familiarity in order to maybe alleviate some of our fears (the unknown can be all too scary at times), and trying to find repeatable patterns somehow convinces us that we can gain some control over our lives and surroundings, at least in the short term.

If we had additional (or just different) senses to what we here on planet Earth have evovled with, I'm sure the universe would look incomprehensibly different to our current view point .. try to think of a way to get someone who has never had eye sight to even begin to comprehend what an image is or what colour is or what eye sight really is - it can't be done.

Our view point is ever so limited in ways that we can never comprehend.

Pip

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3 hours ago, andrew s said:

I am not sure I full or even partially understand what point you are making with this analogy. However, I don't believe we are free to join the dots as we wish but that reality limits and constrains the allowable patterns and that these constraints apply to all "observers".  In this sense it is not chaotic in my view.

But, as I sat Olly I am probably missing your point.

Regards Andrew

I don't think we are free to join the dots in any way we wish. I suspect that our particular perceptions, derived from who and what we are, impose upon us a certain way of joining the dots to form images which we humans have in common but which do not embrace the entire matrix of all existing dots. Other observers might have perceptions which inclined or obliged them to join the dots in different ways to form different images. I think what I'm trying to express is that we may have only a partial and selective grasp of the full reality. And that the full reality might, perhaps, be far more chaotic than our selective perceptions of it. Of course, I have no means of kowing!

Olly

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The human brain evolved to comprehend what was going on within the range of its legs over the period of a year, with a secondary ability to record and predict the very recent past and future  

Comprehending the entire universe and how it works is a big leap that we are physicaly incapable of making. 

Edited by DRT
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7 hours ago, DRT said:

The human brain evolved to comprehend what was going on within the range of its legs over the period of a year, with a secondary ability to record and predict the very recent past and future  

Comprehending the entire universe and how it works is a big leap that we are physicaly incapable of making. 

Agreed. However, we can chip away to extend our grasp. One thing that clearly remains to be done is to learn more about the role of the observer at a quantum level. The days of believing that we can ever stand outside the physical world and observe it without influencing it are probably gone forever. That's quite a change for science, but science is good at dealing with change.

Olly

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8 hours ago, Pippy said:

I'm more inclined to think that we are in no position at all to be telling the universe how it must be, what rules it must follow etc. I tend to think we like to see and experience our lives with some level of familiarity in order to maybe alleviate some of our fears

Pippy I am in full agreement with you. I absolutely agree we can't dictate to reality, it is what it is, but that does not mean we can't build models of reality that allow us to predict it's behavior. Yes we do like familiarity but that does not limit our capacity to build good predictive models. Take modern QM we have no familiarity with its constituent parts or their behavior but we can predict the value of, say the fine structure constant, to 1 part in 10^6

 

7 hours ago, ollypenrice said:

Other observers might have perceptions which inclined or obliged them to join the dots in different ways to form different images. 

I agree what they perceive reality to be will be different just as an insect that "sees" in the UV will see a different world to us. However, for me the belief that reality is independent of the observer leads me to the conclusion that their models of reality must make the same predictions as ours do about observables.

 

7 hours ago, DRT said:

Comprehending the entire universe and how it works is a big leap that we are physicaly incapable of making. 

I think we have already made a good fist of this in the sense we have good predictive models from the very large GR to the very small QM and much in between. If this were not so we would not live in a technology dominated world.

 

12 minutes ago, ollypenrice said:

about the role of the observer at a quantum level

In modern QM the observer (in the sense of a human observer) is irrelevant. While work still needs to be done, however, dechorerence theory provides good answers. This is a good review http://www.springer.com/gp/book/9783540357735 

22 minutes ago, ollypenrice said:

The days of believing that we can ever stand outside the physical world and observe it without influencing it are probably gone forever

Not so in modern QM. Yes we can have an influence but we don't have to. In modern QM the universe as a whole acts as the observer and continues to do so without our help almost all of the time.

Regards Andrew

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14 minutes ago, andrew s said:

Pippy I am in full agreement with you. I absolutely agree we can't dictate to reality, it is what it is, but that does not mean we can't build models of reality that allow us to predict it's behavior. Yes we do like familiarity but that does not limit our capacity to build good predictive models. Take modern QM we have no familiarity with its constituent parts or their behavior but we can predict the value of, say the fine structure constant, to 1 part in 10^6

 

I agree what they perceive reality to be will be different just as an insect that "sees" in the UV will see a different world to us. However, for me the belief that reality is independent of the observer leads me to the conclusion that their models of reality must make the same predictions as ours do about observables.

 

I think we have already made a good fist of this in the sense we have good predictive models from the very large GR to the very small QM and much in between. If this were not so we would not live in a technology dominated world.

 

In modern QM the observer (in the sense of a human observer) is irrelevant. While work still needs to be done, however, dechorerence theory provides good answers. This is a good review http://www.springer.com/gp/book/9783540357735 

Not so in modern QM. Yes we can have an influence but we don't have to. In modern QM the universe as a whole acts as the observer and continues to do so without our help almost all of the time.

Regards Andrew

Thanks for the link to the book. I'll give it a go.

Olly

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3 minutes ago, ollypenrice said:

Thanks for the link to the book. I'll give it a go.

Olly

It's quite expensive so you could start here https://arxiv.org/abs/1404.2635. I think you can get a good idea of the arguments even if you can't follow all the mathematics ( and I certainly can't). 

Regards Andrew

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26 minutes ago, andrew s said:

Pippy I am in full agreement with you. I absolutely agree we can't dictate to reality, it is what it is, but that does not mean we can't build models of reality that allow us to predict it's behavior. Yes we do like familiarity but that does not limit our capacity to build good predictive models. Take modern QM we have no familiarity with its constituent parts or their behavior but we can predict the value of, say the fine structure constant, to 1 part in 10^6

Oh for sure, yes we should certainly keep at it Andrew, most definately, it's too valuable not too. Just a shame we are making a mess of the world we share whilst in the process of doing so.

Just that I tend to think that we should be extremely careful not to fall too deeply into the trap of putting constrants onto how we think we see the universe or how we think we should limit our thinking on how it appears to be (theories etc).

We're in desperate need of many more Alberts and Stephens etc, people who have dared to step outside of any and all current thinking constrants, constrants as in any and all current theories that are taken as being correct and/or fact, or as near as can be (seen as false minimas in the neural world - places where things kind of work well but are also not good to remain there).

 

Tis all good though, so long as we allow ourselves to let go of past 'kind of works or appears to work well' theories et all.

 

Pip

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Fascinating discussion this, reminds me a little of musings I had with fellow hippy types back in my youth but with scientific rather than "spiritual" references. I'd love to join in but I fear I'm well out of my depth, that's assuming there is an "I" :grin:

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1 hour ago, Pippy said:

Just a shame we are making a mess of the world we share whilst in the process of doing so.

There is little link between the beauty of a good scientific theory and they way we decide to exploit them technologically. Human nature tends to dominate.

1 hour ago, Pippy said:

Just that I tend to think that we should be extremely careful not to fall too deeply into the trap of putting constrants onto how we think we see the universe or how we think we should limit our thinking on how it appears to be (theories etc).

I fear the reverse is the case in the example of the search for The Theory of Everything and I regret to say some aspect of Cosmology. Here we are allowing our ideas free range without asking reality what it thinks about them. Some scientist in the TOE game are arguing that predicting observable outcomes should not be the test of a scientific theories validity!

However, I agree with the spirit of your post Pip.

Regards Andrew

 

PS

52 minutes ago, RichLD said:

that's assuming there is an "I"

Of course you are there is, my bright little star... 
I've mile of files 
Pretty file of your forefarther's fruit 
And now to suit our great computer 
You're magnetic ink!

 Graeme Edge

 

Edited by andrew s
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28 minutes ago, andrew s said:

There is little link between the beauty of a good scientific theory and they way we decide to exploit them technologically. Human nature tends to dominate.

I fear the reverse is the case in the example of the search for The Theory of Everything and I regret to say some aspect of Cosmology. Here we are allowing our ideas free range without asking reality what it thinks about them. Some scientist in the TOE game are arguing that predicting observable outcomes should not be the test of a scientific theories validity!

However, I agree with the spirit of your post Pip.

Regards Andrew

 

PS


Of course you are there is, my bright little star... 
I've mile of files 
Pretty file of your forefarther's fruit 
And now to suit our great computer 
You're magnetic ink!

 Graeme Edge

 

Haha, nice one! It's been a very long time since I heard that, must dig it out :biggrin:

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