Not Gravity, Geometry?

LivingDog
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hi Mike, I have looked

hi Mike,

I have looked only briefly at all of your last replies. Right now I am reading Box 1.6 "Curvature of what?" of MTW. Then I will read and reply to your latest set of posts in this thread. BTW, thanks for all the help. Conceptual discussions of physics are a very good and rare thing - so they should always be appreciated. But w/o formalism, they can lead ... any where - good or bad - true or false - and so be leading or misleading. Physics is both equations and concepts. It requires both to have a good (concepts) and solid (formalism) understanding of physics.

When I was an undergraduate student I was told that MTW is called the "Princeton Phonebook" b/c of all the Princeton professors it references. I referred to it as "MTW's blerb about GR" as a joke. Joke may be on me b/c MTW is half as long as the Bible ... and it took me ~3 years to read that.

Anyway, page 32 of MTW says that Riemann "... spent his dying days at 40 working to find a unified account of electricity and gravitation." This didn't gel with your description so I went to Wikipedia.org for his bio to clarify. This is from their page on Georg Friedrich Bernhard Riemann

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Austro-Prussian War

Riemann fled Göttingen when the armies of Hanover and Prussia clashed there in 1866.[1] He died of tuberculosis during his third journey to Italy in Selasca (now a hamlet of Verbania on Lake Maggiore) where he was buried in the cemetery in Biganzolo (Verbania). Meanwhile, in Göttingen his housekeeper tidied up some of the mess in his office, including much unpublished work. Riemann refused to publish incomplete work and some deep insights may have been lost forever.


British TV: I've been a fan.
Wallace & Gromit, Jeeves and Wooster, Carry on Regardless, MPFC, The Rise and Fall of Reginald Perrin, Fawlty Towers, Blackadder, The Young Ones, RED DWARF (the first 6 seasons only), almost any Peter Sellers movie, Shaun of the Dead, Are You Being Served, Yes Minister, Yes Prime Minister, Rumpole of the Bailey, ... the list goes on.

-joe

-LD
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my faith

Mike Hewson
Mike Hewson
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RE: I have looked only

Message 98240 in response to message 98239

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I have looked only briefly at all of your last replies. Right now I am reading Box 1.6 "Curvature of what?" of MTW. Then I will read and reply to your latest set of posts in this thread. BTW, thanks for all the help. Conceptual discussions of physics are a very good and rare thing - so they should always be appreciated. But w/o formalism, they can lead ... any where - good or bad - true or false - and so be leading or misleading. Physics is both equations and concepts. It requires both to have a good (concepts) and solid (formalism) understanding of physics.


Yah. So true. I tend to play alot with the maths, more like shooting baskets in the back yard rather than properly playing a whole game on a court. I need more formal rigour .... but I also dislike what I can't put ( eventually ! ) into everyday words. A difficult tension. :-)

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When I was an undergraduate student I was told that MTW is called the "Princeton Phonebook" b/c of all the Princeton professors it references. I referred to it as "MTW's blerb about GR" as a joke. Joke may be on me b/c MTW is half as long as the Bible ... and it took me ~3 years to read that.


Well, it's way thicker than our local phone book ( City of Melbourne )!! :-)

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Anyway, page 32 of MTW says that Riemann "... spent his dying days at 40 working to find a unified account of electricity and gravitation." This didn't gel with your description so I went to Wikipedia.org for his bio to clarify. This is from their page on Georg Friedrich Bernhard Riemann

Quote:

Austro-Prussian War

Riemann fled Göttingen when the armies of Hanover and Prussia clashed there in 1866.[1] He died of tuberculosis during his third journey to Italy in Selasca (now a hamlet of Verbania on Lake Maggiore) where he was buried in the cemetery in Biganzolo (Verbania). Meanwhile, in Göttingen his housekeeper tidied up some of the mess in his office, including much unpublished work. Riemann refused to publish incomplete work and some deep insights may have been lost forever.


Err, I was talking about the bio of Schwarzchild wasn't I ??? :-)
But yes, he was a brilliant one lost way too young also .... :-(

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British TV: I've been a fan.
Wallace & Gromit, Jeeves and Wooster, Carry on Regardless, MPFC, The Rise and Fall of Reginald Perrin, Fawlty Towers, Blackadder, The Young Ones, RED DWARF (the first 6 seasons only), almost any Peter Sellers movie, Shaun of the Dead, Are You Being Served, Yes Minister, Yes Prime Minister, Rumpole of the Bailey, ... the list goes on.-joe

Wow, I match 4/5 of those..................... with apologies to other countries, the Brits are by far the funniest in my view. Little Britain is the latest gem ... 'computer says no' ..... :-)

Cheers, Mike

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Fayvitt
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In laymans terms. How is

In laymans terms. How is geometry linked to measuring force?

How is Time included in measuring the volume of a cube?

I always thought measuring velocities of cannonballs was physics.

How does one add 'time' to a geometrical coordinate?

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Secondly : when we say geometry it's crucial, though no doubt annoying, to have to consider the basis of measurement. As Einstein found out with Special Relativity, some 'obvious' ideas in classical physics turned out to be wrong, or at least misleading and approximate.

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So finally back to Newton's case of a single central mass that influences another one some distance away - your originally query. The good & bad news is that we have an approximate but not exact solution to the GR equations for this. It's still pretty good and has been observationally well confirmed more than a few times though ( eclipses, Mercury .. ).

So, Einstein's "obvious" ideas in classical physics were misleading and approximate, and there is observational evidence to support your theory, yet your theory is still approximate? How does that differ from the original problem Einstein had?

Edit: Saw a blackhole mentioned. Hasn't Crothers exposed bad maths concerning those? Since they are only a mathematical prediction.

http://www.nowpublic.com/tech-biz/mathematician-claims-black-holes-due-faulty-math-follow

You seem to be adequate with mathematics, so by reading that article you should come to the same conclusion.

Mike Hewson
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RE: In laymans terms. How

Message 98242 in response to message 98241

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In laymans terms. How is geometry linked to measuring force?


That's indeed the trick, there's no 'obvious everyday' answer. :-(

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How is Time included in measuring the volume of a cube?


Not especially. *

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I always thought measuring velocities of cannonballs was physics.


Certainly is.

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How does one add 'time' to a geometrical coordinate?


Time becomes a geometric co-ordinate.

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So, Einstein's "obvious" ideas in classical physics were misleading and approximate


No, Einstein corrected ( even ruled out ) some incorrect classical ideas produced by others. By 'incorrect' I mean those that contradicted experiment.

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and there is observational evidence to support your theory, yet your theory is still approximate? How does that differ from the original problem Einstein had?


I don't have a theory. I'm trying to understand Einstein's, and in doing so I'm sharing my thought's on that.

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Edit: Saw a blackhole mentioned. Hasn't Crothers exposed bad maths concerning those? Since they are only a mathematical prediction.

http://www.nowpublic.com/tech-biz/mathematician-claims-black-holes-due-faulty-math-follow

You seem to be adequate with mathematics, so by reading that article you should come to the same conclusion.


Sorry, I'm focused on Einstein's GR at present. In any case one would rule black holes in or out based on observation. If the maths is faulty then that needs adjusting. There's an oft missed logical truth - a false premise can imply anything.

Beg my forgiveness, but I tend to chuckle when a phrase like 'only a mathematical prediction' is used. I could use maths to predict what happens when you fall off a cliff. The outcome goes well beyond mathematics though .... I think what you mean is that we haven't yet 'seen' a black hole. Careful thought ought reveal an immediate difficulty there, but having said that there is no shortage of observational evidence upon the core of our galaxy ( probably our closest and best candidate ) for which we have no better conclusion of to date. But I appreciate your point. Science never gets it perfectly right, and never will. What is strived for is to obtain progressively better understanding of the world based on careful experiment, in a manner that selects the best from alternate explanations.

Aside : In fact while looking at MTW ( Box 1.10 on page 41 ) I note a quote of Newton's :

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For hypotheses ought .... to explain the properties of things and not attempt to predetermine them except in so far as they can be an aid to experiments.


I reckon this is still exceptionally relevant today, when quite a slab of what is held under the umbrella of 'science' utterly ignores this, to wit : experiments/observations are all too frequently designed to confirm some prior preference/expectation and not enable a choice between competing explanations including diametric opposites if possible.

Generally, one great theme of GR is that it is possible to have a workable theory that predicts observational findings by viewing certain aspects of nature with geometrical ideas. Including bits that we previously wouldn't have thought of doing. Einstein was not the first to consider this, but he was the first to get it pretty right - to date as yet contradicted by observation or bettered by an alternative.

Cheers, Mike.

( edit ) * 'Not especially.' Actually you could have a cube in spacetime, although one might have to accept a cube with four dimensions - width, length, height and persistence. :-)

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Fayvitt
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RE: ( edit ) * 'Not

Message 98243 in response to message 98242

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( edit ) * 'Not especially.' Actually you could have a cube in spacetime, although one might have to accept a cube with four dimensions - width, length, height and persistence. :-)

Philosophy has no place in physics ;) Either do abstract ideas and vague concepts.

Observing black holes, i get the drift. Observing predicted effects of...better statement.

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I reckon this is still exceptionally relevant today, when quite a slab of what is held under the umbrella of 'science' utterly ignores this, to wit : experiments/observations are all too frequently designed to confirm some prior preference/expectation and not enable a choice between competing explanations including diametric opposites if possible.

Good to see you have an open mind to science. Many people seem to have forgotten what you stated above. Science has IMHO become like a religion. Too many things are not allowed to be questioned, even if obviously wrong.

Thanks for the reply.

Mike Hewson
Mike Hewson
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RE: Philosophy has no

Message 98244 in response to message 98243

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Philosophy has no place in physics ;) Either do abstract ideas and vague concepts.


The full title of Newton's masterpiece the 'Principia' includes the term 'natural philosophy'. I think he was essentially wanting to push his contemporaries to actually look at the world they are in, rather than purely examining their own 'inner' world. Tycho Brahe had a head start on this with regard to questions and theories upon the state of the cosmos. His breakthrough was not any terrific model, but the brilliantly simple idea of going out and measuring to an as extreme degree as possible - and then see which ideas can withstand that. He devoted his adult life to that program by constructing and operating a decent observatory - Uraniborg in Sweden. Kepler then came along and built his neat theory upon that large body of data, which is still true to the degree of approximation it represents. Had Tycho not been as obsessively particular as he was, then ellipses and circles would have remained indistinguishable.

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Good to see you have an open mind to science. Many people seem to have forgotten what you stated above. Science has IMHO become like a religion. Too many things are not allowed to be questioned, even if obviously wrong.


Thanks! I see the main ( social ) mechanism is the misuse of the label 'science' like a brand name. You keep the outer wrapping but the box is actually empty.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Rod
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RE: Philosophy has no place

Message 98245 in response to message 98244

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Philosophy has no place in physics ;) Either do abstract ideas and vague concepts.

Without these, physics or (for that matter anything) could not move forward..

There are some who can live without wild things and some who cannot. - Aldo Leopold

Fayvitt
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RE: Without these, physics

Message 98246 in response to message 98245

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Without these, physics or (for that matter anything) could not move forward..

Yes, it could. The old fashioned way. Observe first, then explain it. If you can't see what something is doing, you can't really know, can you?

Multiple universes, i call that a vague concept. How do you explain going from 1 universe to multiple universes? Vaguely, and incoherently, with a bit of mathematical religion thrown in.

M-Theory, i call that an abstract idea. And lots of incoherent mathematics proving a theoretical view of what's not really happening.

Are either helping us with physics? They help me move forward with entertainment, i'll give them that.

tullio
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I would only recall what

I would only recall what Albert Einstein said:
"Theory determines what can be observed".
On the multiple universes idea I agree it is nonsense and I am taking part in a project called QuantumFire by the Cambridge Cavendish Laboratory which strives to undermine the Copenhagen interpretation of quantum mechanics in favor of the pilot wave theory of De Broglie and Bohm just to eliminate such nonsense.
Tullio

Rod
Rod
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What we observe and perceive

What we observe and perceive through our senses is the baseline. All the rest is just relationships. If what we observe or perceive is wrong or incomplete then our relationships could be wrong or incomplete. Therefore I learnt never to hold on to anything to tightly. Including.. 1+1 =2. :-)

There are some who can live without wild things and some who cannot. - Aldo Leopold

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