Hey

Hey

Hey

Hey

Hey

@EmilioPisanty Any idea? I submitted extra photos like you told me to physics.stackexchange.com/questions/507099/…

@EmilioPisanty Speaking of unusual reflection, uhoh just mentioned this old unanswered question in a comment. Any thoughts, or is it outside your field?

physics.stackexchange.com/questions/507106/… Does anyone else understand what OP and others are going on about with this being "unrealistic"? It seems like everyone else commenting is reading a different question than I am or something...

@JMac I mean it is not an unreasonable thought that if you put a small shiplet (can recall the English word) and a huge ocean cruiser on the same river then the shiplet would move faster, is it

@Ezze How is that relevant though? If you are given the velocity of the vessel with respect to water, then a small ship is going to move with the exact same velocity as a large ship relative to the water... because it's literally the information you are directly given.

@JMac I understand, but I'd still think that my example is the source of confusion

As in some might consider it unrealistic that they have the same speed

Even though it is explicitly stated that they do

@Ezze I just don't know how else to explain it to everyone. That is literally irrelevant. Different boats can move at different speeds; but when you are told the speeds, you can and absolutely should ignore that factor.

Hello. I heard that some Physics regulars are Wikipedia editors, so I've come for advice. If I notice a problem that's spread across 8+ Wikipedia pages, how should I most effectively raise my concerns? It seems silly to post the same message on all 8+ Talk pages.

More specifically, I noticed that en.wikipedia.org/wiki/List_of_stars_in_Cygnus and en.wikipedia.org/wiki/List_of_stars_in_Andromeda both have entries for the same star, Kepler-63. I found several more "duplicate" stars, which I have recorded at dpaste.com/0490Q8P

@Kevin Hi. Crossposted to the main Astronomy chat. chat.stackexchange.com/transcript/message/52047867#52047867 It's pretty quiet in there, but you never know.

Thanks :-)

I'm guessing that the dupes that have consistent right ascensions aren't blatantly wrong, but rather the star just happens to be right on the border of neighboring constellations. HAT-P-50, for instance, might really be between Canis Minor and Gemini.

Maybe the star used to be in Gemini, and later the measurements improved and it turned out to be in Canis Major, and whoever added it to its correct page forgot to remove it from the old page

This doesn't explain the four stars whose right ascensions have a discrepancy of eight or more hours though

@JMac Weird. I don't know the others, but I have noticed ja72 making odd remarks from time to time. I just hope they don't go down the track of pushing some non-mainstream pet theory...

@JMac I agree with you. I think this is what trips so may introductory physics students up. They don't know how to separate out what is given, what is relevant, and what is irrelevant.

If we are told the velocity of the boat, then who cares how massive it is, how it got to that velocity, what the captain's name is, etc.

@AaronStevens Yeah, exactly. I’m leaving so many comments because everyone else seems to be only confusing the issue by acting like there is something deeper to consider, when all the information we have completely accounts for the situation.

@JMac Well, you have my up vote.

It also seems like OP is asking a simple, intro to physics vector addition question, and somebody else is trying to bring in fluid flow over the hull and whatever else

@tpg2114 Really what the answers are missing is how the problem didn't specify if Mercury is in retrograde or not.

@AaronStevens And which house Mars is in

On a semi-related note -- thanks to all of our regulars for helping manage content. It makes it much easier on our end when all of you are editing/closing/flagging things

@tpg2114 Gotta get that marshal badge :)

It's very appreciated and it makes moderating a lot easier when we can focus on other things

@AaronStevens Just don't stop once you get it! Heh

@tpg2114 I do feel like there are instances on this site where people completely miss the point of a question. One of the examples that annoyed me in the past was some question along the lines of "What if the sun disappeared and there was no force/torque acting on the Earth. How is angular momentum conserved if the Earth moves in a straight line?"

The question was closed as being "not mainstream physics" because in reality the sun could never just disappear

Yeah, I remember that one. It's unfortunate when another example would have served just as well (string holding a ball gets cut) or whatever

But the point of the question really was about how something moving in a straight line has a constant angular momentum about some point. It was not asking for a GR analysis of a disappearing sun

@tpg2114 Exactly. And when a duplicate question arised I told the OP to switch to that exact string analogy. But I think it had already been closed as well.

In cases like that, I would recommend editing the question yourself -- it doesn't change the intent of the question and works just as well

If OP decides that no, it really must be the sun disappearing, then they can rollback and deal with the consequences of how people vote I guess

I was so surprised to see so many users getting onto the OP about a disappearing sun, when it would be so easy to post an answer getting to the heart of the question. And then if you wanted you cold add in the answer about how this is not a physically realizable system

Yeah... oh well haha

I think if people come across it in the review queue, they are going to vote rather quickly

Scan for keywords, see "sun disappears" and think "oh no, another crap impossible question" and move on

(Not justifying it -- just pointing out where the disconnect might come from)

True. That is how I go through the review queues sometimes tbh

Me too

It's kind of the way the system is set up

But that's why it's important to clarify things if we think we can, rather than suggest them to OP who may not understand the way the site works

True. Good point

@AaronStevens Ironically, this is kind of the opposite of the issue we were discussing yesterday of awakening the inner scientist vs teaching people how to pass physics exams. When you're doing textbook exercises or exam problems you do need to know the conventions underlying how such problems are presented, so you can say "Right, this is a simple vector sum problem, I need to use the vector sum formula".

physics.stackexchange.com/a/506767/127931 I really don't know enough about QM to dispute this; but to me this really seems like a huge assertion without good support. Isn't "many worlds" still a sort of "interpretation" of results instead of an actual statement about reality?

@PM2Ring True. I suppose the distinction is between being a scientist and passing exams/doing problems. Homework problems, certain conceptual problems, are meant to teach a specific thing. For the boat example, you need to focus on the vector addition, not fluid dynamics. For the sun example, we wanted to focus on angular momentum, not an actual disappearing sun

However, I could reason through an argument that awakening an inner scientist is no different. In science you cannot possibly take all parts of a system into account. There are assumptions you will have to make, processes you decide not to include, etc. all to arrive at a reasonable answer for your ressearch

@JMac That answer now has sixty deleted comments.

@rob How annoying is it to police discussions in the comments in general?

@AaronStevens Usually not. We have a good comment culture in our community.

@rob That's good to know. For some reason I always image mods thinking "Ah, here they go again..."

@AaronStevens When it's one or two users who like to argue in comments, we can mod-message them about it. The annoying cases are HNQs like that one, where the comments come from people who aren't within our community and make a bad guess about what we use comments for.

@rob And let's not forget the handful of repeat offenders who use comments to post their non-mainstream theories, where they can't be downvoted...

I have to admit to occasionally posting answer-ish stuff in comments, but I'm trying to break that addiction. ;)

@PM2Ring Flag those. Custom flags are helpful.

So, that was a romp.

@rob Don't worry, I do flag them when I see them.

@JMac AFAIK, all quantum interpretations make the same predictions of what we'll measure when we perform an experiment. If that weren't the case, we could do some experiment and reject interpretations that aren't consistent with the measurements. But it gets tricky because the equations (usually) give us a bunch of possible outcomes with associated probabilities.

The interpretations differ in their claims of how the unobservable "real world" gives rise to the outcome that we do actually observe.

However, with some of the more recent interpretations, there are potentially experiments that could validate that interpretation as the true description of the world, if only we could make sufficiently delicate measurements, eg Penrose's gravity causes collapse thing.

@PM2Ring I’m not sure -all- interpretations would satisfy this. But any of the mainline ones, yeah

But the author of the answer you linked is a fairly typical MWI "evangelist". In my younger days, I was a big fan of MWI, and I devoured stuff like Deutsch's popular works. But those MWI evangelists got so annoyingly persistent that they actually drove me away. :)

(There’s some caveats with this vis a vis pilot wave interpretations due to the whole quantum equilibrium business, but I don’t find it interesting to speculate about that)

I guess what I'm trying to figure out, is "real quantum physics is equivalent to many worlds quantum physics. There really isn't an alternative explanation available." really an accurate way to explain it? From what I understand, "real quantum physics" is equivalent to any interpretation that hasn't been shown to be false. I think what's really bugging me is that it reads like an argument from ignorance, but I don't have the knowledge to tell if it was implying something else

@Semiclassical I tried to cover that with my "However" paragraph. It's hard to summarize a century of the history of QM interpretations in half a page. ;)

Lol, just a bit

One rendering might be: the way people actually use QM is closest in spirit to MW than anything else

Id find that a pretty dubious claim tho

Conservation of misery/absurdity

QM interpretations are all equally absurd, but they’re all absurd in different ways

If you try to make an interpretation that eliminates one absurdity, then the absurdity just shows up somewhere else

@JMac "real quantum physics is equivalent to many worlds quantum physics. There really isn't an alternative explanation available." is pure unadulterated evangelism.

I could see somebody arguing for the first sentence. But they’d have to argue it, and hence the second sentence isn’t sensible

As someone who knows only the bare minimum, it seemed like such a strange statement to say other interpretations don't explain anything; but he seems so willing to accept that MWI is a correct interpretation without questioning the underlying fundamentals of that in the same way; as if just appealing to MW does explain things

Right

There’s a reason I consider myself a Bohm sympathizer but not a Bohmian, for instance

@Semiclassical Agreed. So it's silly to latch on to one and reject the others. Treat them all as useful ways to wrap your head around quantum issues, and for each problem choose an interpretation that helps you to think about what's going on. And then choose another & see if it still makes sense. ;)

There’s things I like about it (huzzah for the guidance equation) but it does seem to leave you stuck in a bad spot as far as relativity goes

@PM2Ring my old standby as far as that goes: smbc-comics.com/comic/know-your-linguistic-philosophies

I gotta commend user151841 for putting a lot of effort into trying to understand that answer chat.stackexchange.com/rooms/99694/…

As I've said before, I have a soft spot for the Transactional Interpretation. It's just a shame that Cramer wasn't able to develop it, and he adopted some sleazy evangelistic practices of his own. But I still like to tease MWI people with it, just to demonstrate that I'm not a MWI "true believer" merely because it makes bizarre claims. :)

@PM2Ring this does raise a question I’ve had before: Practically speaking, which topics in QM lend themselves to various interpretations?

For instance, MW seems to appeal to cosmologists and computing people

By contrast, Bohm mostly seems popular amongst philosophers :P

@Semiclassical Speaking of gymnastics, check out the Ross sisters Solid Potato Salad. There is no trick photography, even though they appear to defy the laws of physics and anatomy. :D

pilot waves are popular amongst vzn; if I understand many of his comments correctly

@Semiclassical Part of the reason for that is that when cosmologists started doing QM the von Neumann flavour of Copenhagen was in vogue, and it's pretty hard for conscious to collapse a wave function in the early days of the universe, when it was devoid of conscious observers. :) MWI doesn't suffer from that problem.

@JMac I find ir hard work reading vzn's comments, mostly due to his bizarre refusal to use the 1st person singular pronoun.

@PM2Ring that went from interesting to impressive to disturbing quite fast

@JMac ehhhhhhh

vzn’s line is fluids

@Semiclassical :D That's a common reaction. One of the sisters eventually became a chiropractor.

there’s certainly historical connections—de Broglie’s double solution idea is in that vein

But the vein of Bohm I hew to is in the way Bell posed it, where the key point is that one can introduce trajectories into QM without breaking any of the formalism

Whether you -should- do that is another question: one can well accuse that perspective as taking the math too literally

But that’s a rather different POV than, say, what Bush-Couder have tried to argue for by analogy

For Bush-Couder experiments, there’s three time scales: a slow time scale where QM behavior shows up, a medium scale where pilot wave dynamics, and underlying both is a fast time scale which is really just hydrodynamical

@JMac He's saying some pretty good stuff.

Pilot wave theory in the way I like is just the slow and medium scales, with no postulation of another scale beneath both

Aaaaaanyways

A funny little side effect of teaching intro physics labs so much is that I actually like Bohm stuff more

But I should probably resist the urge to ramble about that

I kinda get the fixation on fluids. It has an ancient & honourable pedigree. We can go back to the ancient Greeks, eg Thales. And in more modern times, from Descartes to Lord Kelvin, people tried models involving vortices in a primordial fluid. But they couldn't make it work, although Kelvin's ideas of knotted vortices inspired the creation of knot theory, which is some pretty nice mathematics.

Yeah

And fluid mechanics remains incredibly useful in various areas of physics

but that hardly guarantees that it’s fundamental/foundational to physics

The death of the aether caused fluids to go out of vogue, but a few people kept the faith. But a big problem with fluids is that Navier-Stokes is mostly intractible. So abandoning GR for fluids is jumping out of the frying pan into a different frying pan. :)

Lol

I’m sympathetic to that problem, mainly because I’ve never managed to git gud at numerical Bohmian mechanics

And a big part of that is my ignorance of numerical methods for fluid mech

@PM2Ring I am still digesting everything from yesterday. And the best way I digest things is to take a "day off". I let everything sink in entirely and completely. Then I am able to continue. I just got off of a very very stressful day at work. I had to run from building to building. Telling people what to do. And people werent doing thete jobs correctly. It ... It was a mess.

@PM2Ring I am so tired. And I just want to relax for tonight. I still want to learn. But in my shape right now I can listen to what you would teach me. But it wouldn't stay at all. I just wish today wasn't a bad and tiring day today. So I don't want to waste your energy and time if its going to go in one ear and out the other.

@PM2Ring I wanted to let you know so we can make the most of the learning time you're so kindly giving me.

Boy BERT-LARGE is SLOWWWW

what the...I deleted a layer and it made the model run slower...how's that make any sense...