md65536

swansont, I'd be much more comfortable having the expert label that's on every post show the specific field of expertise, rather than removing it completely. Can that be done? Thanks!

Yes thank you for renouncing the label. What field of physics do you have expertise in? It would be a lot less confusing if the "expert" label showed what specific expertise you have because a lot of replies you've made do seem to be appropriately labelled "expert", just not I believe the ones I've mentioned. It would be vastly different to myself and others to be discussing relativity with an expert in some other field of physics vs. discussing it with an expert in relativity, especially when we disagree on something. It causes great self-doubt and confusion to disagree with an expert, even when all external evidence shows they're wrong. The problem isn't how you understand relativity, it is how you mislead others on the parts you misunderstand, resist corrections, and use the "expert" label as an indicator of authority. I didn't ignore your references on rapidity, I replied to everything I thought was relevant, and I figured in the end we came to an agreement about the topic.

Yes, to show that your non-expert lack of knowledge on the topic spans multiple threads. My reply to your mathematics is, 'Did you write out the post yourself or copy it from somewhere without attribution? Do you understand that what you wrote does not explain, clarify, or relate to the statement "The worldine is the transition between Alice and Bob's reference frames."?' The quotes link to the threads. There should be an arrow icon in the top right corner of the box.

"The worldine is the transition between Alice and Bob's reference frames." is not re-inventing the wheel, it's reinventing the stick and calling it a wheel. I asked for clarification and didn't get it (or, I don't understand it). Does "The worldine is the transition between Alice and Bob's reference frames." make sense to you as a description of the established meaning of "worldline"? This is not just a one-off error, but a repeated source of confusion for others as well. For example in a thread talking about different engines on a single train: reply: It is either merely confusing to the point of nonsense, or it is evidence of a non-expert misunderstanding of the term and the concepts being discussed. Can you explain what you mean by this? If you're correct then the Alice and Bob statements are consistent. For example, say "lightning striking the front of a moving train" is a typical event in SR examples. What is the reference frame of that event? I asked google and the first result is from https://www.physics.udel.edu/~jim/PHYS309_16F/Class Notes/Class_2.pdf "Events are not tied to any individual reference frames. Events are measured by observers who do belong to particular inertial reference frames." I think that's correct. Did you write out the post yourself or copy it from somewhere without attribution? Do you understand that what you wrote does not explain, clarify, or relate to the statement "The worldine is the transition between Alice and Bob's reference frames."?

Then I just want to say, I don't do this gleefully. Early on getting interested in science, I'd search on the internet, and put huge stock in expert information, and I see others now doing it and being told they don't understand, and are then told nonsense that is not possible to understand. I think it can affect a person's approach to science for years if they're new and can't distinguish pseudoscience when they're told it's expert knowledge. Alright, here's the first example: A confused or incomplete use of the word "worldline". Are they referring to an object that they fail to mention? Inconsistent statements about Alice and Bob. Claiming an event has its own reference frame indicates a lack of understanding of the basics of events. Claiming the spacetime interval is a distance and a path, not even getting the dimensions right. In one single reply, this demonstrates a pattern of using established terms to mean whatever else they want to, which is pseudoscience. I ask for a reference for this information but didn't get one. I asked how the use of "worldline" could possibly be consistent with the normal use, and got this: Is this word salad? It certainly has nothing to do with a transition between reference frames originally described. If it was designed to be confusing use of jargon to avoid supporting or correcting the original statement, it worked. Here's the previous misuse of terms (rapidity and boost) that I called out: https://www.scienceforums.net/topic/133833-why-lorentz-relativity-is-true-and-einstein-relativity-is-false/?do=findComment&comment=1264941 Discussed in thread: https://www.scienceforums.net/topic/133837-is-rapidity-a-measure-of-acceleration/ In the above threads, there are often pages of equations posted without citation, that use the same terms correctly and identically to what can be found elsewhere but are unrelated to the question being asked. This is another form of pseudoscience, mixing in real science to give an air of legitimacy to previous false and only tangentially related statements. The misunderstanding of so many established terms in relativity in just 2 posts demonstrates a level of understanding that is less than "expert." The pattern of attempting to argue and confuse instead of admitting or correcting mistakes demonstrates being intentionally misleading. The constant posting of content identical to that which can be found elsewhere, but does not answer the question being asked, shows a lack of understanding of the topic. Please tell me that you think all the examples I posted are reasonable expert statements and I'll accept I'm mistaken and give up on this site.

The examples are misinformation about basic concepts, where at least twice I've supported my position with the first line of a wikipedia entry. Is it appropriate to link to examples in this thread, or should such issues generally be handled with private messages?

Yes, and there's evidence that they're not just common errors because when they're pointed out, not only are they not acknowledged or corrected, but they're repeated or supported with tangential arguments.

It's come up for me repeatedly. Is there anything I can do about it? Are posts made by experts noticed by other experts? I assume occasional errors are noticed and ignored as inconsequential? I've gotten into several arguments with an expert but don't remember another expert ever weighing in on either side. Are such arguments not noticed? It feels like gaslighting because it suggests the possibility that other experts have seen the posts and ignore them because they agree with them, and that I'm the one who doesn't understand the basics. I don't suppose it would be useful or appropriate to post examples here?

re. How does a person get expert status? Does the same process apply to losing status, or is it permanently applied with no possible further consideration? Say for example an expert is consistently posting pseudoscience, specifically of the type "Use of misleading language -- Using established terms in idiosyncratic ways, thereby demonstrating unfamiliarity with mainstream work in the discipline," in a way that misinforms readers. Is it appropriate to "report" such posts as pseudoscience? Or is there a better way to call staff attention to the behaviour? Or is it allowed that resident experts can consistently reply to questions in the mainstream science forums with pseudoscience?

Where are you getting your information? How is this consistent with anyone else's use of the term "world line"? Can you please provide a reference? https://en.wikipedia.org/wiki/World_line "The world line (or worldline) of an object is the path that an object traces in 4-dimensional spacetime." How can that possibly be a transition between Alice and Bob's reference frames? How many dozens of people have to come to this site and be told by an "expert" that they "have a fundamental misunderstanding", and then be given such utterly embarrassing nonsense from you? How many go away believing it, knowing only that an expert told them something beyond the possibility of understanding, and never get the truth? You really should request that the site removes your "expert" status, for the sake of everyone. I would like to request that they do that. Is there an official way to do that?

If the equivalence principle is used, then there should be an equivalent relative velocity between source and receiver. Consider 2 sources falling into a black hole, and only one of them realizes it and accelerates outward so that it can remain stationary relative to the EH. Near the EH, it would need to have a velocity approaching c relative to the free-falling source, so there would be a Doppler shift between the two. The sources would have to appear differently, and external sources would have to appear different to them, depending if they're stationary or falling. Consider a rocket accelerating upward, so that the bottom of the rocket is equivalent to being deeper in a gravitational well relative to the top. Light from the top is blue-shifted when seen at the bottom, but the top and bottom remain at relative rest. However, consider two sources at the top of the rocket, both emitting a single pulse of light. One of the sources is fixed to the rocket and accelerating, and the other is inertial but set up so that it is momentarily at rest with the other source at the moment the pulse is emitted. Both pulses should be blue-shifted the same amount when seen by the bottom of the rocket, even though the rocket will have a relative velocity with one of the sources when it is seen. Or to put it another way, since the rocket is accelerating and light takes time to cross the distance of the rocket, the velocity of the receiver at the moment of reception will be different than the velocity of the source at emission. The blueshift can be entirely attributed to this difference in velocity, based on reasoning when source and emitter are replaced with equivalent but inertial particles.

No. The centripetal force is Fc = mv^2/r, so greater r means greater v, which means a larger Lorentz factor relative to the centre of the wheel. Would that give the same answer as a gravitational redshift analysis assuming negligible spaceship mass?

I think we'd both have been helped a lot if it was more common on this site for people to discuss and accept corrections, but it always feels like a fight to try. Because of that I think this site is harmful for learning at least about relativity. All of that makes sense now. The constant acceleration implies constant proper acceleration here, I just point that out because I've confused it with constant coordinate acceleration in a single reference frame before. Am I wrong to assume that someone who understands what you wrote here would see that previous statements from you (going back years) don't make sense?

Rapidity is not equal to proper velocity. The chart at the top of https://en.wikipedia.org/wiki/Proper_velocity shows how they (and velocity in natural units) relate. Also, Rapidity is not a type of boost.

You're referring to "celerity", which is different. https://en.wikipedia.org/wiki/Proper_velocity https://en.wikipedia.org/wiki/Rapidity "For one-dimensional motion, rapidities are additive." I'm sorry to hear that, but yes he's not using the terms correctly.