tag:blogger.com,1999:blog-9074529824943791718.post7272393774791888780..comments2012-01-20T10:44:14.520-05:00Bryanhttp://www.blogger.com/profile/07379669532781325751noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-9074529824943791718.post-49533529978686143632011-11-25T18:24:41.621-05:002011-11-25T18:24:41.621-05:00Sorry, but this example makes no sense to me. What you are doing is to create a coordinate system that you then use from two separate perspectives, finding them to clash, when those happenings can&#39;t meet for any of the observers.<br /><br />If there was a real possibility for you to see &#39;times arrow&#39; count backwards, as you seem to assume here? Then &#39;time reversibility&#39; should be possible in all accelerations. You can use gravity to show that this isn&#39;t the case. <br /><br />Although all mass, according to the equivalence principle is &#39;gravitationally constantly uniformly accelerating&#39; there is no such thing in SpaceTime as you observing any other &#39;clock&#39;, as defined by gravity, to &#39;tick&#39; backwards relative your clock. So either you, or the equivalence principle, should be wrong here.<br /><br />Yoron.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-47403550100679579232009-06-22T16:09:42.435-04:002009-06-22T16:09:42.435-04:00I am a decendant of King Harold 11. I am eagure to learn more.<br />Cherry.weaver@btinternet.comAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-52219188305758103212009-03-14T13:42:00.000-04:002009-03-14T13:42:00.000-04:00&gt;&gt; should we really *demand* a non-singular coordinate description?<BR/><BR/>Not necessarily. It just does not make always sense to use them beyond the singularity (like in your example).wolfganghttp://wbmh.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-77566025843481814932009-03-14T09:14:00.000-04:002009-03-14T09:14:00.000-04:00Thanks for the comments Wolfgang. Your observations are interesting and correct. First: If a signal is sent to the astronaut from the event of Harold's crowning and the event of his death, then a) the astronaut won't ever receive the signals if he keeps accelerating, because they'll stay behind his event horizon; and b) if the astronaut stops accelerating, then he will receive the signals in the correct order.<BR/><BR/>So the Universe does 'censor' the bad judgments my astronaut will make using the standard simultaneity relation in a screwy reference frame.<BR/><BR/>Second: The accelerated observer's description of the order events does match the Rindler coordinate system, and so is singular at the origin. But should we really *demand* a non-singular coordinate description? After all, many metrics (e.g. Schwarzschild) provide singular descriptions of spacetime, but remain perfectly reasonable in regions *outside* the singularity.Bryanhttp://www.blogger.com/profile/07379669532781325751noreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-78550393340394433412009-03-14T08:13:00.000-04:002009-03-14T08:13:00.000-04:00One more thing, your accelerated observer uses a coordinate system with a coordinate singularity (the same event has two different coordinates)...wolfganghttp://wbmh.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-45875155645713896162009-03-14T04:35:00.000-04:002009-03-14T04:35:00.000-04:00Bryan,<BR/><BR/>notice that the accelerated observer sees the events in the same sequence as any other observer.<BR/>In other words, your definition (and it is a definition) of simultaneous is just not very helpful for the accelerated observer.wolfganghttp://wbmh.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-16110827000353970842009-03-12T21:33:00.000-04:002009-03-12T21:33:00.000-04:00Of the many things I love about you, Jonathan, that you almost always spike the ball when set up is perhaps at the forefront!Justinhttp://www.jsytsma.comnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-12566573551384468472009-03-12T19:51:00.000-04:002009-03-12T19:51:00.000-04:00Those both look like "gap" to me!Jonathannoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-81548923289903204632009-03-12T15:32:00.000-04:002009-03-12T15:32:00.000-04:00Interesting. I would have thought that you wanted to answer: No, time can no more unfold in the 'wrong' direction than it can unfold in the 'right' direction.Justinhttp://www.justinsytsma.comnoreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-42192218359745696512009-03-12T11:20:00.000-04:002009-03-12T11:20:00.000-04:00Well, I'm arguing there is no objective right or wrong direction for unfolding. So how about: Yes, time can unfold in the 'wrong' direction as much as it can unfold in the 'right' direction.Bryanhttp://www.blogger.com/profile/07379669532781325751noreply@blogger.comtag:blogger.com,1999:blog-9074529824943791718.post-26354055326135424682009-03-10T09:19:00.000-04:002009-03-10T09:19:00.000-04:00So, is the answer to the titular question, "yes," "no," or "gap"?Jonathannoreply@blogger.com