The discussion centers on the relationship between coordinate time and proper time for null geodesics in the context of general relativity. It is established that a null geodesic can take infinite coordinate time while covering finite proper time, specifically when transitioning from a radial coordinate r > R to r → ∞. The Lagrangian approach is discussed, emphasizing that proper time is defined along timelike worldlines, and it is clarified that proper time cannot be defined for null paths. The conversation also highlights the importance of understanding affine parameters and the distinction between timelike and null geodesics.
PREREQUISITESStudents and professionals in theoretical physics, particularly those focusing on general relativity, spacetime geometry, and the mathematical foundations of gravitational theories.
binbagsss said:Does anyone really post on a forum expecting a yes or no answer ? No you expect discussion? Or what the hell are you going to learn ?
stevendaryl said:Well, if you posted to generate discussion, that's fine. There was quite a bit of discussion about the topic, so you should be happy. But then you complained that nobody answered your question, which makes it sound like you had a specific question you wanted an answer to. Nobody knows what that question is.
You're unsatisfied with the answers you have been given, but nobody knows why, and you can't tell them.
binbagsss said:and then someone complained about me not having the background knowledge of such posts, when I hadnt asked for it !
yes, fair enough if you had pointed towards that, but at no point did ii point towards killing vector fields. what followed was someone merrily tapping away at their keyboard banging on about killing vector fields, and then a post asking ME where is my background knowledge !Mister T said:When a question is asked a back-and-forth discussion almost always follows. Sometimes the discussion goes over my head and I have to just gean what I can from it and try to learn more about it if I'm interested. Education, formal or otherwise, is much more than learning how to answer questions. It involves understanding.
binbagsss said:i complained because people went astray
erm nah. i don't think the world revolves around me. rather, if you think a discussion may be useful by taking a de-tour, you should mildly talk about the subject, or introduce it, and ask whether that person has the background knowledge for it or not, before ASSUMING they DO NOT, writing an essay about ut and getting your knickers in a twist about the fact that they don'tstevendaryl said:There is no way that the discussion can "go astray" if there isn't a specific question to answer. So it seems to me that either you ask a specific question (and then you can complain if nobody answers it) or you can spark a general discussion, and then let it go where it will. There is no basis for complaint in the latter case.
binbagsss said:erm nah. i don't think the world revolves around me.
u really want me to repeat myself?stevendaryl said:Your complaints seem to suggest otherwise. You're upset that people didn't spend more time figuring out what you want from this discussion and complying with it.
binbagsss said:u really want me to repeat myself?
i believe they do about 6 posts ago, you can't let it go since felt the need to reply to my clarificaiton posts which i was asked for.stevendaryl said:No. I told you what I want. I either want you to ask a specific question, or else let the discussion go where it will, without complaining.
Nobody has any idea what you want out of this discussion.
Presumably from a module on general relativity. What was, if there was one, the recommended text(s)?binbagsss said:The question comes from an exam paper from my university in the UK...
binbagsss said:i believe they do about 6 posts ago, you can't let it go since felt the need to reply to my clarificaiton posts which i was asked for.
binbagsss said:i believe they do about 6 posts ago