Page 19 from the book GRAVITATION

 1 Nicolaas Vroom Page 19 from the book GRAVITATION Sunday 13 August 2017 2 Paparios Re :Page 19 from the book GRAVITATION Sunday 13 August 2017 3 Nicolaas Vroom Re :Page 19 from the book GRAVITATION Sunday 13 August 2017 4 The Starmaker Re :Page 19 from the book GRAVITATION Sunday 13 August 2017 5 Nicolaas Vroom Re :Page 19 from the book GRAVITATION Sunday 13 August 2017 6 The Starmaker Re :Page 19 from the book GRAVITATION Sunday 13 August 2017 7 Paparios Re :Page 19 from the book GRAVITATION Monday 14 August 2017 8 Nicolaas Vroom Re :Page 19 from the book GRAVITATION Wednesday 16 August 2017 9 Paparios Re :Page 19 from the book GRAVITATION Wednesday 16 August 2017 10 mlwo...@wp.pl Re :Page 19 from the book GRAVITATION Thursday 17 August 2017

Page 19 from the book GRAVITATION
10 posts by 4 authors

1 Page 19 from the book GRAVITATION

From: Nicolaas Vroom
Datum: Sunday 13 August 2017
Page 19 from the book GRAVITATION by MTW is interesting because it makes an evaluation between the relativity theory of Einstein versus Newton. To read the related text please select this link:
http://users.pandora.be/nicvroom/GRAVITATION_page_19_560.jpg

The text is divided in 4 paragraphs, The first part is like a general introduction. The second part shows text what Newton thought. The third part shows text by Einstein. The fourth part is more of general nature and gives a summerisation. The problem is, that this page is not a sound comparison between Newton and Einstein. When you want to compare Einstein with Newton than you should compare with the book "Newton's Principia" for the common Reader by S. Chandrasekhar. This is an excellent book which gives a complet overview about Newton.

In part 4 SR is mentioned. The most important issue is that Newton is not about SR but about GR. For Newton the issue is gravity. For Einstein it is both SR and GR. That means if you want to compare Einstein with Newton you should only compare, how each handles gravity related issues. As such this page gives the wrong impression.

In part 2 straight lines are discussed. For Newton that is not an important issue. Bended lines are an issue. The trajectory of a comet is an issue. To describe such a trajectory you have to calculate the sum off all the forces caused by Sun and all the planets in the solar system. When this force is not zero (starting from the assumption that the sum of all the forces should be zero) the reaction force will cause the trajectory to bend. That is Newton. As such part 2 gives a complete wrong impression.

In part 3 absolute space is discussed. That is not an issue for Newton. For Newton what is important is the center of gravity of a collection of objects. The sum of all the forces on that point with m=0 is zero. That means that point is either at rest or it moves at a constant speed. As such also part 3 gives the wrong impression.

For Newton time is an important issue to calculate speed and acceleration. To do that he uses a pendulum. Newton derived the correct formula to explain the oscillations of a pendulum. This formula is a function of g and as such belongs to the domain of gravity.

It is my impression if n objects were considered than Newton always studied all the n objects together, in one global coordination system. I do not think he studied individual objects from a local perspective (inertial reference frame) because the path of each object undergoes accelerations and is bended.

What should be mentioned at page 19 is that Newton considers that forces induce instantaneous action and that is wrong. Instead he should have proposed the opposite and that forces propagate in time. It is important to place this oversight in the right context i.e. when he lived. For Einstein SR is simple. That maybe true, but with SR you cannot calculate the trajectories of planets. For Newton gravity is a complex problem, there is no simple solution to explain the movements of the planets.

In short page 19 underscores the importance of Newton in relation to the movement of the planets and overestimates, in comparison, the importance of Einstein. What is even more important Einstein uses concepts which IMO makes understanding of the issues more complex than it is. For example if you want to understand the movement of the planets you should discard (treat separately) everything that is related towards light. Moving clocks should not de used. Reaction rates should be handled with care.

Nicolaas Vroom http://users.pandora.be/nicvroom/GRAVITATION_page_19.htm

2 Page 19 from the book GRAVITATION

From: Paparios
Datum: Sunday 13 August 2017
Translate message into English - show quoted text - It is really unfair to talk about a partial part of page 19 of that book, while totally ignoring the previous 18 pages, boxes and figures delivering the complete views and reasonings which justify the important conclusion of locality.

3 Page 19 from the book GRAVITATION

From: Nicolaas Vroom
Datum: Sunday 13 August 2017
On Sunday, 13 August 2017 15:09:30 UTC+2, Paparios wrote:
 > El domingo, 13 de agosto de 2017, 9:28:00 (UTC-3), Nicolaas Vroom escribió:
 > > In short page 19 underscores the importance of Newton in relation to the movement of the planets and overestimates, in comparison, the importance of Einstein. What is even more important Einstein uses concepts which IMO makes understanding of the issues more complex than it is. For example if you want to understand the movement of the planets you should discard (treat separately) everything that is related towards light. Moving clocks should not de used. Reaction rates should be handled with care.
 > It is really unfair to talk about a partial part of page 19 of that book, while totally ignoring the previous 18 pages, boxes and figures delivering the complete views and reasonings which justify the important conclusion of locality.

It is IMO unfair when you compare two scientist based on the concept locality i.e. local inertial frames when one of the two does not use that concept but starts from a global coordinate system.

What is fair is when you compare a simulation (all planets around the sun) using the theories of both scientist to predict the future. In that sense each theory without any shortcut. See for example chapter 39.

Nicolaas Vroom

4 Page 19 from the book GRAVITATION

From: The Starmaker
Datum: Sunday 13 August 2017
Translate message into English - show quoted text - albert einstein created SR at some point in time.. then for ten years later he studied Newton gravitation, and came up with GR.

Ten years is a long time...between SR and GR.

Einstein had to learn what is this thing called...Gravity.

It took him ten years.

You don't wake up knowing this stuff, ...you got to learn it.

5 Page 19 from the book GRAVITATION

From: Nicolaas Vroom
Datum: Sunday 13 August 2017
On Sunday, 13 August 2017 20:12:46 UTC+2, The Starmaker wrote:
 > Nicolaas Vroom wrote:
 > > In short page 19 underscores the importance of Newton in relation to the movement of the planets and overestimates, in comparison, the importance of Einstein. What is even more important Einstein uses concepts which IMO makes understanding of the issues more complex than it is. For example if you want to understand the movement of the planets you should discard (treat separately) everything that is related towards light. Moving clocks should not de used. Reaction rates should be handled with care. Nicolaas Vroom http://users.pandora.be/nicvroom/GRAVITATION_page_19.htm
 > albert einstein created SR at some point in time.. then for ten years later he studied Newton gravitation, and came up with GR. Ten years is a long time...between SR and GR. Einstein had to learn what is this thing called...Gravity. It took him ten years. You don't wake up knowing this stuff, ...you got to learn it.

What is your point? I have nothing against SR nor GR.

The problem is you cannot compare SR with Newton's Law and then claiming that Newton's Law is wrong (More or less)

Nicolaas Vroom

6 Page 19 from the book GRAVITATION

From: The Starmaker
Datum: Sunday 13 August 2017
Translate message into English - show quoted text - you wrote:

 > In part 4 SR is mentioned. The most important issue is that Newton is not about SR but about GR. For Newton the issue is gravity. For Einstein it is both SR and GR. That means if you want to compare Einstein with Newton you should only compare, how each handles gravity related issues. As such this page gives the wrong impression.

maybe I got the wrong impression...

but who would compare einstein's SR with Newton's GR??? Certaintly not me, then who?

7 Page 19 from the book GRAVITATION

From: Paparios
Datum: Monday 14 August 2017
Translate message into English El domingo, 13 de agosto de 2017, 14:51:36 (UTC-3), Nicolaas Vroom escribió:
 > On Sunday, 13 August 2017 15:09:30 UTC+2, Paparios wrote:
 > > El domingo, 13 de agosto de 2017, 9:28:00 (UTC-3), Nicolaas Vroom escribió:
 > > > In short page 19 underscores the importance of Newton in relation to the movement of the planets and overestimates, in comparison, the importance of Einstein. What is even more important Einstein uses concepts which IMO makes understanding of the issues more complex than it is. For example if you want to understand the movement of the planets you should discard (treat separately) everything that is related towards light. Moving clocks should not de used. Reaction rates should be handled with care.
 > > It is really unfair to talk about a partial part of page 19 of that book, while totally ignoring the previous 18 pages, boxes and figures delivering the complete views and reasonings which justify the important conclusion of locality.
 > It is IMO unfair when you compare two scientist based on the concept locality i.e. local inertial frames when one of the two does not use that concept but starts from a global coordinate system.

The purpose of the first 19 pages of Gravitation is not to compare Newton with Einstein. You should read and understand better what it is written there before spouting nonsense.

 > What is fair is when you compare a simulation (all planets around the sun) using the theories of both scientist to predict the future. In that sense each theory without any shortcut. See for example chapter 39. Nicolaas Vroom

Again, you take bit and pieces of a book without making the effort of understanding what it is being written (in that case the Post Newtonian Expansion)

8 Page 19 from the book GRAVITATION

From: Nicolaas Vroom
Datum: Wednesday 16 August 2017
On Monday, 14 August 2017 00:20:27 UTC+2, Paparios wrote:
 > El domingo, 13 de agosto de 2017, 14:51:36 (UTC-3), Nicolaas Vroom wrote:
 > > On Sunday, 13 August 2017 15:09:30 UTC+2, Paparios wrote:

 > > > It is really unfair to talk about a partial part of page 19 of that book, while totally ignoring the previous 18 pages, boxes and figures delivering the complete views and reasonings which justify the important conclusion of locality.
 > > It is IMO unfair when you compare two scientist based on the concept locality i.e. local inertial frames when one of the two does not use that concept but starts from a global coordinate system.
 > The purpose of the first 19 pages of Gravitation is not to compare Newton with Einstein.

All(?) the pages breathe this difference.

At page 4 Figure 1.1 almost show the same information. "In Newtonian theory this effect is ascribed to gravitation action at a distance from a center of atraction, symbolized here by the stem of the apple" In Newtonian theory each object gets an "action at a distance" by all the other objects considered. Each action follows a straight line. The reaction is that the path of the object is not straight.

"According to Einstein a particle gets its moving orders locally, from the geometry of space time right where it is." According to Newton each object gets its orders instantaneous from all the objects considered.

"Its instructions are simple: to follow the straigtest possible track (geodesic)" I expect that these instructions (very bad wording) are extremely complex.

 > You should read and understand better what it is written there before spouting nonsense.

In some sense the more I read in the book GRAVITATION the less I understand. See also below.

 > > What is fair is when you compare a simulation (all planets around the sun) using the theories of both scientist to predict the future. In that sense each theory without any shortcut. See for example chapter 39.
 > Again, you take bit and pieces of a book without making the effort of understanding what it is being written (in that case the Post Newtonian Expansion)

Paragraph 39.9 "Velocity of PPN coordinates relative to Universal Rest frame" here we read: "Thus far it is has been assumed tacitly that the center of mass of the solar system is at rest in the PPN coordinate system. Is this really a permissible assumption?"

What I try to understand is the evolution op the planet Mercury over a period of 10000 years.

Equation 39.64 is interesting. What you clearly can see is how complex GR is compared to clasic Newton.

At page 1096 you can read: "That spacetime geometry is very complicated. It includes the spherical fields of the sun and all the planets etc."

Read also the bottom part after *: "All these "individual fields" etc are the best abandoned (they cease to be useful) when one passes from the post_Newtonian limit to the full Einstein theory."

That is what I expect, when you want to calculate how the sun behaves in our galaxy using GR.

Nicolaas Vroom

9 Page 19 from the book GRAVITATION

From: Paparios
Datum: Wednesday 16 August 2017
Translate message into English El miércoles, 16 de agosto de 2017, 10:07:42 (UTC-3), Nicolaas Vroom escribió:
 > On Monday, 14 August 2017 00:20:27 UTC+2, Paparios wrote:
 > > El domingo, 13 de agosto de 2017, 14:51:36 (UTC-3), Nicolaas Vroom wrote:
 > > > On Sunday, 13 August 2017 15:09:30 UTC+2, Paparios wrote:
 >
 > > > > It is really unfair to talk about a partial part of page 19 of that book, while totally ignoring the previous 18 pages, boxes and figures delivering the complete views and reasonings which justify the important conclusion of locality.
 > > > It is IMO unfair when you compare two scientist based on the concept locality i.e. local inertial frames when one of the two does not use that concept but starts from a global coordinate system.
 > > The purpose of the first 19 pages of Gravitation is not to compare Newton with Einstein.
 > All(?) the pages breathe this difference.

You really have great difficulty in reading plain English. It is also clear from your reading you pick some text and totally ignore the context of the writing, as you show below.

 > At page 4 Figure 1.1 almost show the same information. "In Newtonian theory this effect is ascribed to gravitation action at a distance from a center of atraction, symbolized here by the stem of the apple"

You see? you picked a piece of the text ignoring even what the figure is about: The Riemnanian geometry of spacetime.

The ants are observed moving through the apple (worldline), which through the magnifying glass are seen as straigth lines (in 2D), while on the apple are geodesic tracks.

Then the text explains the observations according to Newtonian and Einstein theories. Nowhere are Newton and Einstein being compared as scientists.

 > In Newtonian theory each object gets an "action at a distance" by all the other objects considered. Each action follows a straight line. The reaction is that the path of the object is not straight.

This makes no sense and it is not what fig 1.1 says or represent.

 > "According to Einstein a particle gets its moving orders locally, from the geometry of space time right where it is." According to Newton each object gets its orders instantaneous from all the objects considered. "Its instructions are simple: to follow the straigtest possible track (geodesic)" I expect that these instructions (very bad wording) are extremely complex.

On the contrary, observations of Nature show how simple these instructions are in the universe: just follow a geodesic, that is the shortest path through spacetime, since that path is the path which uses the minimum energy.

 > > You should read and understand better what it is written there before spouting nonsense.
 > In some sense the more I read in the book GRAVITATION the less I understand. See also below.
 > > > What is fair is when you compare a simulation (all planets around the sun) using the theories of both scientist to predict the future. In that sense each theory without any shortcut. See for example chapter 39.
 > > Again, you take bit and pieces of a book without making the effort of understanding what it is being written (in that case the Post Newtonian Expansion)
 > Paragraph 39.9 "Velocity of PPN coordinates relative to Universal Rest frame" here we read: "Thus far it is has been assumed tacitly that the center of mass of the solar system is at rest in the PPN coordinate system. Is this really a permissible assumption?" What I try to understand is the evolution op the planet Mercury over a period of 10000 years.

¿?

10 Page 19 from the book GRAVITATION

From: mlwo...@wp.pl
Datum: Thursday 17 August 2017
W dniu sroda, 16 sierpnia 2017 23:12:59 UTC+2 uzytkownik Paparios napisal:

 > > "Its instructions are simple: to follow the straigtest possible track (geodesic)"

https://en.wikipedia.org/wiki/Gravitational_lens The idiot physicist, however, is too stupid to truly understand these brilliant, simple instructions, and that's why he insists these lines are bent.

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