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I think that your perception of the audience as homogeneous (and like you) is wrong, and I have evidence for that in the form of upvotes and much politer commen

I think that your perception of the audience as homogeneous (and like you) is wrong, and I have evidence for that in the form of upvotes and much politer comments than yours. If you don't care about that, then I think that we should agree that nobody profits by you or I replying to one another's HN comments in future.

gus_massa 9y ago
I didn't like the original comment "everything moves through spacetime at c.". I was trying to write a reply, but I saw your comment. I think your comment is too long and too technical, but it's correct and explain why the original comment is wrong. So I upvoted it. The problem is that is too long and too technical, so the main ideas are lost and many people prefer some wrong handwaving. Some recommendations: * Try to keep the answer shorter. Link to the Wikipedia article if possible. Perhaps ignore part of the original comment to make the reply shorter. * Try to avoid too much technical jargon. This is a technical forum. You can assume everyone has Calculus 101 and Algebra 101, and a few more elementary courses, but nobody has advanced knowledge of all the topics. It's difficult to explain in simple words why I don't like the original comment. The answer is strangely in one of your other comments. > "Sure, you can always choose useless systems of coordinates." It's too short! I'd try to add some details: The problem with "everything moves through spacetime at c" is that you must "sum" the squares of distance "x" in the laboratory reference frame and the time in the reference frame of the moving spaceship "s" (and fix the units, sorry). So you get a nice property that is valid if you use properties that are measure in different reference frames. But 99.99% of the time, life it's much better if you don't mix measurements in different reference frames. [My version still needs a lot of fixes, fix the units, perhaps replace "reference frame" with "astronaut", add at least a formula, ... I guest that with 1 or 2 more hours I can fix it, but this is a deeply nested thread that nobody will read and I have to go to eat ... https://xkcd.com/386/ https://xkcd.com/386/ ]
- raattgift 9y ago
  > this is a deeply nested thread that nobody will read I read it. > too technical Too technical for the comment or too technical for HN period? > Link to the Wikipedia article if possible I do link to things that go into further detail in many of my comments. However, I think the relevant (English-language) wikipedia articles for this thread are bound to be much longer and more technical. The simple English wikipedia versions, to the extent they even exist, are generally not worth linking to. Do you think it would have been right to simply drop https://www.wikiwand.com/en/Line_element#/General_spacetime https://www.wikiwand.com/en/Line_element#/General_spacetime as the bulk of the content of my original disliked-by-you comment? > I'd try to add some details The details were already in the replied-to message that people seem to either like or dislike. :-) > I guest that with 1 or 2 more hours I can fix it FWIW, I only took a few minutes. Is it likely that anyone would spend an hour or two on any HN comment (especially a down-thread one) as opposed to a blog posting, article or comment elsewhere? Indeed some of my original motivation is exactly https://xkcd.com/386/ https://xkcd.com/386/ however the point wasn't just to be right, but also to try to advance someone's (not necessarily the original writer's) understanding of a line element and that line elements are meaningful (and in particular typically nonzero) for light.

gus_massa 9y ago

I didn't like the original comment "everything moves through spacetime at c.". I was trying to write a reply, but I saw your comment. I think your comment is too long and too technical, but it's correct and explain why the original comment is wrong. So I upvoted it. The problem is that is too long and too technical, so the main ideas are lost and many people prefer some wrong handwaving. Some recommendations: * Try to keep the answer shorter. Link to the Wikipedia article if possible. Perhaps ignore part of the original comment to make the reply shorter. * Try to avoid too much technical jargon. This is a technical forum. You can assume everyone has Calculus 101 and Algebra 101, and a few more elementary courses, but nobody has advanced knowledge of all the topics. It's difficult to explain in simple words why I don't like the original comment. The answer is strangely in one of your other comments. > "Sure, you can always choose useless systems of coordinates." It's too short! I'd try to add some details: The problem with "everything moves through spacetime at c" is that you must "sum" the squares of distance "x" in the laboratory reference frame and the time in the reference frame of the moving spaceship "s" (and fix the units, sorry). So you get a nice property that is valid if you use properties that are measure in different reference frames. But 99.99% of the time, life it's much better if you don't mix measurements in different reference frames. [My version still needs a lot of fixes, fix the units, perhaps replace "reference frame" with "astronaut", add at least a formula, ... I guest that with 1 or 2 more hours I can fix it, but this is a deeply nested thread that nobody will read and I have to go to eat ... https://xkcd.com/386/ https://xkcd.com/386/ ]

raattgift 9y ago
> this is a deeply nested thread that nobody will read I read it. > too technical Too technical for the comment or too technical for HN period? > Link to the Wikipedia article if possible I do link to things that go into further detail in many of my comments. However, I think the relevant (English-language) wikipedia articles for this thread are bound to be much longer and more technical. The simple English wikipedia versions, to the extent they even exist, are generally not worth linking to. Do you think it would have been right to simply drop https://www.wikiwand.com/en/Line_element#/General_spacetime https://www.wikiwand.com/en/Line_element#/General_spacetime as the bulk of the content of my original disliked-by-you comment? > I'd try to add some details The details were already in the replied-to message that people seem to either like or dislike. :-) > I guest that with 1 or 2 more hours I can fix it FWIW, I only took a few minutes. Is it likely that anyone would spend an hour or two on any HN comment (especially a down-thread one) as opposed to a blog posting, article or comment elsewhere? Indeed some of my original motivation is exactly https://xkcd.com/386/ https://xkcd.com/386/ however the point wasn't just to be right, but also to try to advance someone's (not necessarily the original writer's) understanding of a line element and that line elements are meaningful (and in particular typically nonzero) for light.