Path: csiph.com!feeder.erje.net!2.us.feeder.erje.net!feeder.usenetexpress.com!feeder-in1.iad1.usenetexpress.com!border1.nntp.dca1.giganews.com!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!buffer1.nntp.dca1.giganews.com!nntp.earthlink.com!news.earthlink.com.POSTED!not-for-mail NNTP-Posting-Date: Sun, 13 Aug 2017 13:12:40 -0500 Message-ID: <59909697.3A5A@ix.netcom.com> Date: Sun, 13 Aug 2017 11:12:39 -0700 From: The Starmaker Reply-To: starmaker@ix.netcom.com X-Mailer: Mozilla 3.04Gold (WinNT; U) MIME-Version: 1.0 Newsgroups: sci.physics.relativity Subject: Re: Page 19 from the book GRAVITATION References: <79d7d435-f74b-4d95-9a12-4334fb92f661@googlegroups.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Antivirus: Avast (VPS 170813-0, 08/13/2017), Outbound message X-Antivirus-Status: Clean Lines: 84 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 108.219.229.47 X-Trace: sv3-Yc2E+q+qvhl2iE/j9vQNfKJzhw9m8Fhc3/SLnMQWkgUlgPRAlKmCNjUOEr62d4mALinv3XRfTKZ1MKr!UERg0GSHhRL2BuGE4ZWVg8hLifFSs1KPXOsBiakZ91tlhNqFjh41Q6Fols1kHIO7nhuffQg6Abc0!2dU4Vt8YGyE= X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 5338 Xref: csiph.com sci.physics.relativity:428543 Nicolaas Vroom wrote: > > 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 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.