Path: csiph.com!weretis.net!feeder6.news.weretis.net!feeder.usenetexpress.com!feeder-in1.iad1.usenetexpress.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!buffer1.nntp.dca1.giganews.com!buffer2.nntp.dca1.giganews.com!nntp.earthlink.com!news.earthlink.com.POSTED!not-for-mail NNTP-Posting-Date: Wed, 23 Aug 2017 12:46:18 -0500 Message-ID: <599DBF68.90B@ix.netcom.com> Date: Wed, 23 Aug 2017 10:46:16 -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: Why is there more than one explanation for the Twin Paradox References: <1cb6775d-d2c1-498b-9576-088e3e7ed2be@googlegroups.com> <4790542.Sb9uPGUboI@PointedEars.de> <587d73ca-c675-4557-99a1-0d85d758a1ff@googlegroups.com> <0a540f5f-3cbc-4851-b3e6-f5e0554d4466@googlegroups.com> <5752f78d-73ce-4af2-bc10-3554845e70f0@googlegroups.com> <2f9d5b32-1908-4e2b-974d-c887e670b447@googlegroups.com> <32aafcb3-75e1-4729-b0f6-264134a60909@googlegroups.com> <2671e131-36b0-4c20-bd09-c4cf4769e6f0@googlegroups.com> <599B2155.5DDD@ix.netcom.com> Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Antivirus: Avast (VPS 170823-12, 08/23/2017), Outbound message X-Antivirus-Status: Clean Lines: 47 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 108.219.229.47 X-Trace: sv3-SDpsINTj+dKOO0N1Gzau3Tjyb8ftVErrQWW3YT+QdoPTRVzG0T7JIN6NKevLMkRv2YK9/91NF3tRn20!v6VQSo1vphS/+PzGbw07nxw25lFoGiTdvafECzV8zPkiejS4jPWn4zRsnQbYWoTyFH7hcpF8tCXU!8i7tUPrt2g== 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: 4060 Xref: csiph.com sci.physics.relativity:429843 Nicolaas Vroom wrote: > > On Monday, 21 August 2017 20:07:20 UTC+2, The Starmaker wrote: > > Paparios wrote: > > > > > > El lunes, 21 de agosto de 2017, 10:58:38 (UTC-3), Nicolaas Vroom escribió: > > > > > > > > I understand that. Part of the problem is described at the pages 21 > > > > and 315 of the book GRAVITATION. > > > > The two figures are almost identical but they are not. > > > > The mathematics is the same, which makes it difficult. > > > > For me one problem is to calculate the path length in a real experiment > > > > i.e. how can you calculate the clock readings. > > > > > > On the contrary, in the case of the twin paradox (which is the subject of > > > this thread) you do not need to calculate the clock readings (even if > > > that is quite easy to do with simple geometrical diagrams). > > > You only need to compare the clocks readings when they reunite (the > > > clocks then are side by side and you only need to look at the clocks > > > displays). > > When you want to understand the twin paradox you have to understand > the concept of worldline and propertime of the moving twin (at least > that is the message I get based on the different postings) > > That is why I showed the example based on the movement of Our Galaxy, > the Sun, the Earth (or Marcury) and the Moon to demonstrate that it is very > complicated to calculate the length of such a worldline. > > I do not think there are simple geometrical diagrams. > It is easy to observe the readings but they are difficult to predict > in general! > > Anyway it is much more then a thought experiment. > > > Which clock contains the correct time? > > That is a very good question. I do not know. That is why I think > you should study all from one reference frame and use only one clock. > (And in some sense to forget the whole concept of worldlines, except > if there is some other reason to use it) > > Nicolaas Vroom well, if your watch is running slow..it means you have the incorrect time.