General Question about this part of the forum

[AmirSafavi]

Hi,

I just joined physicsforum.com and have a great interest in physics.
Looking at the previous posts here, there seem to be a huge amount of variation in the quality of posts here.

The membership here seems to be polarized between people whom I would call illiterate (affectionately, since they are at least interested in physics, and maybe grabbing a very rudimentary book like Halliday's Physics or A.P. French's Special Relativity would do them great service), and people who have done their homework and maybe even understand the difference between time, energy, etc.

I was wondering if this forum could provide useful for someone actually willing to do their homework and ask real question in physics not claiming to have invented a new "prepetual motion machine" or another "grand theory".

Regards,
Amir

 

[Doctordick]

I sympathize with you whole heartedly!

Hi,

I just joined physicsforum.com and have a great interest in physics.
Looking at the previous posts here, there seem to be a huge amount of variation in the quality of posts here.

The membership here seems to be polarized between people whom I would call illiterate (affectionately, since they are at least interested in physics, and maybe grabbing a very rudimentary book like Halliday's Physics or A.P. French's Special Relativity would do them great service), and people who have done their homework and maybe even understand the difference between time, energy, etc.

I was wondering if this forum could provide useful for someone actually willing to do their homework and ask real question in physics not claiming to have invented a new "prepetual motion machine" or another "grand theory".

Regards,
Amir

I agree with you one hundred percent. I have no idea what the extent of your education is (I happen to have a Ph.D. in theoretical physics but have been out of the business for many many years) but if you do have a good understanding of physics, I think you will find that, even on the other threads, the actual quality of the posting is not very high. I excuse them because it is called the "Physics Help and Math Help – Physics Forum" which I guess could be taken to imply little education.

From my perspective, there is no forum where competent physics is discussed. If you find one, I would appreciate knowing about it. I am retired and have very little direct opportunity to discuss physics on the level that interests me. At least this forum allows direct posting of mathematical functions.

I am always willing to help anyone learn physics. If I can be of any help to you, let me know.

Good luck in your search for mental stimulation -- Dick

 

[AmirSafavi]

thanks for the reply

Hi DrDick

Thanks for the quick reply. I'm glad there finally seems to be a place where I could ask questions regarding physics.

Actually I'm not all that educated myself. I'm a junior EE undergraduate at a good Canadian university. I'm good at math and have basic understanding of physics (at the level of the first few volumes of berkeley physics and maybe griffiths E&M, rudin for analysis).

I don't have good access to anyone who could answer my question regarding many parts of physics, (except my dad who's quite competent, but I don't want to bug him too much) and have been looking for a forum like this.

I guess i'll just have to ignore the "spam" on this forum though. Might take some more time to get answers but the people here seem to be quite helpful and fast anyhow.

Thanks again,
Amir

 

[Doctordick]

Physics and Math Expertise?

Hi Amir,

I would be happy to help you with anything I can; however, I seldom look at any sections except for "Theory Development" as I have been exiled to that section. The "Theory Development" is apparently a catch all for "crackpots" and the powers that be have decided I am a crackpot and transfer any posts I put elsewhere to this section.

The only real problem I have with that assignment is that no competent physicists or mathematicians (except for myself that is) bother reading this section.

I will give you an example of what I am talking about. I find it quite sad that, after reading and posting to this forum for a number of months, I am quite convinced that there is no one either reading or posting on this forum (and on this section particularly) who could tell me if the following equation is true or false, given that V is the volume of an n dimensional sphere:

V_n(r)\,=\,\frac{2^n}{n!}\Gamma\left(\frac{n+1}{2}\right)\Pi^{\frac{n-1}{2}}r^n .
​

If there is an error in the above expression, does anyone on the forum think they can show us the error or, if it is correct, can anyone prove it? This would not be so bad except for the fact that the forum touts itself as a "Physics Help -- Math Help" forum. Where is the help and what do they know about the subjects?

Please guys, someone convince me I am wrong!

Dick

PS good luck on your studies!

 

[Chi Meson]

Amir:

A lot of folks avoid this sub-forum because it quickly gets nasty. This is not a forum exclusively for "crackpots," but it is nice that there is a place where anybody can say anything. If it were twenty years ago "string theory" discussions would have been found in this sub-fourm, but as it has gained acceptance, it has its very own forum.

Go to some of the other forums for discussions about more specific topics. IF you don't know where to post it, then stay in the "general" forum. Come back here when you feel like opening your mind a bit (but remember, if your mind is open too far, your brains fall out).

The homework help zone is the place to go for hints on solving homework problems.

NB: use the "forum jump" drop-down menu at the bottom of the screen to go to the forum of your choice.

 

[krab]

n-dimensional hypersphere?

Doctordick: Your formula is correct, but there is a simpler form. I typed in hypersphere and volume and got over 4000 pages. Among them,

http://ai.eecs.umich.edu/people/dreeves/misc/HyperSphere.html
http://planetmath.org/encyclopedia/Sphere.html

So... can't you use Google? I am disappointed in you.

 

[Nereid]

Welcome to Physics Forums Amir!

Have you had a look round the rest of Physics Forums? Not only the Physics sub-forums, but also the Astronomy and Cosmology ones?

Some people like to test their understanding of physics by trying to understand some of the more credible ideas posted here in Theory Development. IMHO, there are some quite interesting posts in this sub-forum.

 

[Integral]

I must disagree with docdick. There are many very knowledgeable posters in these forums. The TheoryDevelopment sub forum is the place were pretty much anything goes. If you think you have proven Einstein wrong, this is the place to present your arguments.

If you want to have a discussion about Physics as taught in the US universities, stay in the main Physics forums.

 

[russ_watters]

I was wondering if this forum could provide useful for someone actually willing to do their homework and ask real question in physics not claiming to have invented a new "prepetual motion machine" or another "grand theory".

Though entertaining the way it is, it'd give this site a little more credibility if the "Theory Development" forum really were for theory development and not just as a junkyard for junk science.

Feel free to try and change that (and welcome to the site)...

P.S. be wary of those with a superiority complex in this section of the board especially.

 

[Antonio Lao]

The volume of a unit n-sphere is given by

V = \frac{\pi^{\frac{n}{2}}}{\Gamma(1+\frac{n}{2})}

This gives correct answer for n=3.

 

[Doctordick]

To Krab and Antonio Lao,

Thank you for the "simpler" expression; however, both of you seemed to miss the central point of my comment. You both took the position that "finding and authority" was the solution to your problem whereas I was pointing out that understanding math and physics meant being able to figure out the result for yourself. Neither of you gave a proof of the statement; nor was the proof in the references you quoted.

My complaint is that the level of physics "understanding" on this forum is quite low. Understanding something does not mean being able to find an authority who knows the answer, understanding is being able to personally defend the statement. Without that, science is no more than a religion. It seems to me that most of the people on this forum are posting well beyond what they actually understand.

Without looking up source publications, could either of you write down the integrals represented by Feynman's notation for the terms in a QED expansion. Yeah, they are pretty pictures and the interactions they are meant to indicate is quite clear; however, I would call "understanding" a presentation using such notation to mean you could write down the actual integrals meant by the pictures or write a computer program to calculate them. Or at least have some idea of the expansion the collection is used to express.

People on this forum throw around such things as if they know what they are talking about when, in fact, I suspect most of them are just padding their posts with things which are well over their heads. I am not saying that one cannot discuss physics unless they can explicitly explain each and every esoteric expression but rather that they should not hold forth on ideas which they cannot defend on an intimate level: i.e., talk about what they understand, not what has impressed them.


Now of course, this is all just opinion and I could well be wrong. Maybe science should be taken as a religion; belief is apparently an important aspect of people's self image.

Have fun -- Dick

 

[Antonio Lao]

To me the main purpose of science must be to answer the question "why?" All we been doing in science is answering the question "how?"

Feynman made himself known as a genius in physics because he is very good in answering the question "how?" If I'm remembering correctly, When ask whether he wants to live his life over again, Feynman answered that a second life would be boring since he already knew the things he wanted to seek in the first life.

Einstein was famous because of his physical insights not his knowledge of math. The math he used still cannot completely describe his insights. This is the tensor calculus. To me, a math concept is just a model of reality. Reality is more than we can hope to understand at this point in time. As what he used to say: "reality has its own independent existence." All experimental findings are just an approximation of this underlaying reality that we are so desperately seeking.

The reality I'm seeking is the quantization of one dimensional space. And I've been asking for help (maybe not directly) in this forum for my lack of knowledge in math and physics.

For need of new insights there is no place to start than the authorities of old insights. It is my belief that any insight is replaceable by better and more convincing new insight. This apply not only to science but to social life and politics. The bottomline is the preservation of the human race and a better living for the briefness and preciousness of each life on Earth for now and generations to come.

 

[Nereid]

To Krab and Antonio Lao,

Thank you for the "simpler" expression; however, both of you seemed to miss the central point of my comment. You both took the position that "finding and authority" was the solution to your problem whereas I was pointing out that understanding math and physics meant being able to figure out the result for yourself. Neither of you gave a proof of the statement; nor was the proof in the references you quoted.

My complaint is that the level of physics "understanding" on this forum is quite low. Understanding something does not mean being able to find an authority who knows the answer, understanding is being able to personally defend the statement. Without that, science is no more than a religion. It seems to me that most of the people on this forum are posting well beyond what they actually understand.

Without looking up source publications, could either of you write down the integrals represented by Feynman's notation for the terms in a QED expansion. Yeah, they are pretty pictures and the interactions they are meant to indicate is quite clear; however, I would call "understanding" a presentation using such notation to mean you could write down the actual integrals meant by the pictures or write a computer program to calculate them. Or at least have some idea of the expansion the collection is used to express.

People on this forum throw around such things as if they know what they are talking about when, in fact, I suspect most of them are just padding their posts with things which are well over their heads. I am not saying that one cannot discuss physics unless they can explicitly explain each and every esoteric expression but rather that they should not hold forth on ideas which they cannot defend on an intimate level: i.e., talk about what they understand, not what has impressed them.


Now of course, this is all just opinion and I could well be wrong. Maybe science should be taken as a religion; belief is apparently an important aspect of people's self image.

Have fun -- Dick

Whether PF members can derive such expressions for themselves, from first principles, is one consideration (I suspect quite a few could). Another might be 'gee, I've seen this before, and remember working something similar out. It's nothing like what I work on now, but I reckon if I could dig up my textbook, I'd have no difficulty refreshing my ability.'

Then there's the other aspect of physics, or science in general.

"My goodness, I have no idea how to derive such formulae! But I sure do know how to analyse Hubble images and spectra (and those from Keck, Gemini, etc)! I'm more than capable of downloading the publicly available data from WMAP, performing my own analyses on it, and verifying that the results reported in the peer-reviewed papers are in accord with the data upon which they're based, and even doing analyses that the authors didn't think of (or mention), that extend the purported test. In fact, when analysing some images last year, I found some unusual objects, which it turns out had been predicted, but never observed before."

Physics needs those who are good at equations and those who are good with instruments.

 

[Doctordick]

Whether PF members can derive such expressions for themselves, from first principles, is one consideration (I suspect quite a few could).

I would hope there were, but I have seen little evidence of it in any posts.

Another might be 'gee, I've seen this before, and remember working something similar out. It's nothing like what I work on now, but I reckon if I could dig up my textbook, I'd have no difficulty refreshing my ability.'

And I am not bothered by those people either except for the fact that, in an area called "Theory Development", such things should really be at their fingertips before they step into criticize.

Then there's the other aspect of physics, or science in general.

"My goodness, I have no idea how to derive such formulae! But I sure do know how to analyse Hubble images and spectra (and those from Keck, Gemini, etc)! I'm more than capable of downloading the publicly available data from WMAP, performing my own analyses on it, and verifying that the results reported in the peer-reviewed papers are in accord with the data upon which they're based,

Again, I wouldn't argue with you except for the fact that, in order to determine if the data upon which they are based is in accord with what they are reporting, you need to at least understand what they are reporting.

and even doing analyses that the authors didn't think of (or mention), that extend the purported test.

Most certainly!

In fact, when analysing some images last year, I found some unusual objects, which it turns out had been predicted, but never observed before."

Congratulations, I am proud of you.

Physics needs those who are good at equations and those who are good with instruments.

At no time would I really argue with anything you say; except for the fact that we are posting to a supposed "Theory Development" division of this forum which has been interpreted by many to be a catch all for crackpots. I really suspect that is a consequence of the fact that theory development is really an issue not well understood by a lot of physicists.

The structure of the forum makes the suggestion that the forum should be divided between theory and experiment in a manner much like the fields are divided in the educational institutions but doesn't live up to the job.

One problem the forum clearly has is the great variation in the background of the people posting. A lot of the posts are repeats of ideas which do little more than reintroduce flawed views which have already been debunked a great number of times. Misunderstandings of relativity are the single most popular example of that problem.

If I were in charge of the forum, I would introduce a very simple solution to that circumstance. When such an issue has been thoroughly debunked, the moderator should lock the thread, remove all irrelevant posts to the thread and move the entire thread to a section called a FAQ division. Having done that, the original post in the original thread should be hidden from everyone except the person who posted it and linked directly to the locked thread in the FAQ division.

Following the creation of such a thread, the next time the same misunderstood issue arises, the moderator/mentor can very easily simply hide the new post from from everyone except the person who posted it and link it directly to the locked thread already in existence.

In order to facilitate such an operation, all posts should have another button analogous to the "bad post" button which might be an "already discussed" button to notify the moderator/mentor of the fact that someone feels it is in that category. It might be reasonable to require a comment as to what specific FAQ thread it belongs in and why, with the author's comments on what is wrong with the original posters position. If the moderator/mentor feels that the comments are worth keeping, he can add them to the FAQ representation of the question. Of course, a notice should go to the poster that such a thing was done.

Such a thing would be very effective in several ways. First, it would cut down on the repetitiveness of such things, cleaning up the forum considerably, and second, it would provide the student with a much more extensive argument against his position and better description of the more reasoned position than he receives with the current structure. And finally, it would improve the continuity of the threads worth reading considerably

I know that I just ignore people who can't handle the concept of infinity for example even though I think I could offer some very reasonable insights. The reason I don't comment is that, with the current structure of the forum, responding to such posts is a waste of time; most of the comments I would make have already been made many many times.

After all, this is called a Physics Help and Math Help forum and it should be designed to provide the best help possible. There is a reason we don't have kinder garden classes and graduate classes in the same school room. The great thing about the web is that it has the possibility of allowing people to see what is being said without disturbing the discussion but a little thought has to be put into the structure which will best fit the bill. The web could be the greatest thing for education since the invention of printing. It just has to get a little organization.

So I am full of Bull up to my ears! Old men have a right to their opinions.

Have fun -- Dick

 

[Doctordick]

To me the main purpose of science must be to answer the question "why?" All we been doing in science is answering the question "how?"

I believe it is exactly the question WHY? which I am answering in my thread "why you should like my perspective". An issue very rarely addressed in physics.

Have fun -- Dick

 

[chroot]

At no time would I really argue with anything you say; except for the fact that we are posting to a supposed "Theory Development" division of this forum which has been interpreted by many to be a catch all for crackpots. I really suspect that is a consequence of the fact that theory development is really an issue not well understood by a lot of physicists.

The real problem is that virtually none of the people developing theories here are physicists -- they are simply laypeople with delusions of grandeur.

We could certainly refer to this subforum as "The Nut House" or "Fruitcakes 'R' Us" or virtually any number of more apt monikers. We could also simply ban all the crackpots altogether -- something we used to do. We don't do those things because we don't condone insulting people, and because, as Nereid says, some threads here are actually quite interesting for both laypeople and professionals. We also don't like the idea of abject censorship; as moderators, we rarely delete posts or otherwise pass judgement on them in any way at all besides just making sure they are in the most relevant forum.

A lot of the posts are repeats of ideas... Having done that, the original post in the original thread should be hidden from everyone except the person... might be an "already discussed" button to notify the moderator/mentor of the fact that someone feels it is in that category.

Much of what you suggest is already done -- we routinely post links to already-extant threads when someone brings up a repeated idea. We don't exactly like repetition, but we would not be a useful forum without tolerating some of it.

In general, I think you misunderstand our purpose. We are not out to build an encyclopedia here. We are not wikipedia. We are physicsforums, and we welcome discussion on any topic, even if it has already been discussed before. Much of the discussion is indeed repetitious, but then, so is every Physics 101 class ever taught in college -- surely you don't suggest that colleges should just hand a copy of a physics textbook to all their students, tell them "well, this has all been discussed already," and send them home. We don't want to simply become a compendium of facts; we want to be a group of bright and enthusiastic members who take the time to help others with personally-tailored replies. The pedagogical value of a live question-and-answer session is far and away larger than the pedagogical value of a chapter in a textbook, even when the textbook admittedly provides the exact same information.

- Warren

 

[Doctordick]

The real problem is that virtually none of the people developing theories here are physicists -- they are simply laypeople with delusions of grandeur.

That is very understandable. And it behooves those who understand physics and math to make it clear why knowledge of the fundamentals is necessary to such work.

We could also simply ban all the crackpots altogether -- something we used to do. We don't do those things because we don't condone insulting people, and because, as Nereid says, some threads here are actually quite interesting for both laypeople and professionals.

I would agree with you; however I think there are a few readers of the forum who do have a decent understanding of physics and there should be a place where such discussions can take place without fighting the morass of uneducated posts by those "simple laypeople with delusions of grandeur". For the most part, they are very nice people and are only trying to understand the same things the rest of us want to understand; their only problem is that they cannot comprehend the subtle aspects of physics and math, many of which require considerable time and study to really fathom.

I noticed that you did not comment on my observation that "there is a reason we don't have kinder garden classes and graduate classes in the same school room".

We also don't like the idea of abject censorship; as moderators, we rarely delete posts or otherwise pass judgement on them in any way at all besides just making sure they are in the most relevant forum.

And I support you wholeheartedly with that effort. My impression of the situation is rather that, when it comes to serious theoretical discussions, you don't have a relevant forum. I can understand that as competent discussion of theory development is a very rare event and, for the most part, the absence of such a thing is not even noticed.

However, were there to be such a sub-division, I think it would benefit a lot of lay people (and some professionals also) to see how serious theory development is approached. Even in most graduate schools, there is a very significant lack of communication between theorists and experimentalists. I suspect this is because they tend to look at things quite differently. I could be wrong, but there might be a significant number of young theoreticians out there who would like to put their ideas to competent criticism and would be willing to explain some of the subtle issues to those laypeople. I remember when I was a graduate student; theoretical physics is a rather lonely field.

Much of what you suggest is already done -- we routinely post links to already-extant threads when someone brings up a repeated idea. We don't exactly like repetition, but we would not be a useful forum without tolerating some of it.

When you say that you "post links", do you mean that you insert a URL in a post created in answer to a posting of that repeated idea or do you mean that their post is actually linked to the associated arguments? I was thinking of the second which is quite a different thing as it can not be ignored.

In general, I think you misunderstand our purpose. We are not out to build an encyclopedia here. We are not wikipedia. We are physicsforums, and we welcome discussion on any topic, even if it has already been discussed before. Much of the discussion is indeed repetitious, but then, so is every Physics 101 class ever taught in college -- surely you don't suggest that colleges should just hand a copy of a physics textbook to all their students, tell them "well, this has all been discussed already," and send them home. We don't want to simply become a compendium of facts; we want to be a group of bright and enthusiastic members who take the time to help others with personally-tailored replies. The pedagogical value of a live question-and-answer session is far and away larger than the pedagogical value of a chapter in a textbook, even when the textbook admittedly provides the exact same information.

Again, I agree with you wholeheartedly and I would not want to place any impediment to such an effort as I think it is very valuable. However, I think you miss some very powerful options which are possible and not used (as far as I am aware).

For example, if you had an "advanced theory development" division where a mentor/moderator could make some subtle alterations, I might suggest the following:

Suppose there is a thread where something serious is being discussed and a post is made by someone who is in somewhat over his head. First, as an aside, I want to point out that, on occasion, people who are in over their head can make comments which seriously impact such a thread (scientists can often overlook subtle issues). In that case, the moderator should leave the post where it lies. However, if the post really has no bearing on the thread, the moderator and/or others should post their reasons why they don't feel it belongs and, instead of leaving it there, insert it as a new thread in the old "theory development" division, adding to that original post a URL to the post in the advanced thread which was the impetus to this "misplaced" post.

In addition to change, I would also suggest that a URL should be placed in the advanced thread imbedded (under the title "A lay question!", "A lay comment!" or perhaps just "A lay post!") which would lead to wherever the post had been moved. This would allow anyone following the advanced thread to go look at what the question was and give him the opportunity to perhaps help that lay person understand what he was confused about. Or perhaps bring about a reversal of the original decision as the information necessary to perform that reversal is still extant. (Everybody makes mistakes!)

All this is put forth to remove confusion and add intellectual structure to the forum without instituting censorship. In the end, I think the forum would serve the purpose you wish even better than it does now. And a lot of the steps suggested above could be performed by scripts which are not difficult to design.

Of course, my view of the circumstance could be wrong; but, if so, I would like to see your reasons for disagreement.

Have fun -- Dick

 

[Nereid]

"My goodness, I have no idea how to derive such formulae! But I sure do know how to analyse Hubble images and spectra (and those from Keck, Gemini, etc)! I'm more than capable of downloading the publicly available data from WMAP, performing my own analyses on it, and verifying that the results reported in the peer-reviewed papers are in accord with the data upon which they're based, and even doing analyses that the authors didn't think of (or mention), that extend the purported test. In fact, when analysing some images last year, I found some unusual objects, which it turns out had been predicted, but never observed before."

Physics needs those who are good at equations and those who are good with instruments.

Again, I wouldn't argue with you except for the fact that, in order to determine if the data upon which they are based is in accord with what they are reporting, you need to at least understand what they are reporting.
Most certainly!
Congratulations, I am proud of you.
At no time would I really argue with anything you say; except for the fact that we are posting to a supposed "Theory Development" division of this forum which has been interpreted by many to be a catch all for crackpots. I really suspect that is a consequence of the fact that theory development is really an issue not well understood by a lot of physicists.

To clarify one thing: I believe that many folk who have but second year university physics and maths under their belts can do the kind of thing I stated (in quotes). Further, with the extensive public funding of much leading edge research, the governments providing that funding have insisted that the results - even the raw data - be made available to the public. This is surely seventh heaven for those with new theories!

Further, with initiatives such as
http://www.stecf.org/astrovirtel/ coming on stream, many powerful data mining and analysis tools will be available ... to ALL!

Interesting discoveries are made all the time, by amateurs, using online data such as SOHO, and the refinement of newly discovered NEO orbits, through tracking down pre-covery images in, for example, DSS plates is entirely within the reach of tens of thousands of folk with PCs, a broadband connection, and some programming ability (or good image analysis software).

Is it really too much to expect that those with new ideas in physics (or at least astrophysics and cosmology) should check even simple predictions of their ideas against this cornucopia of data and analysis tools? Or - even more basically - specify some tests which might be relevant?

 

[Doctordick]

Is it really too much to expect that those with new ideas in physics (or at least astrophysics and cosmology) should check even simple predictions of their ideas against this cornucopia of data and analysis tools? Or - even more basically - specify some tests which might be relevant?

I think, if you read over the actual threads on this forum, you will discover that it certainly is "too much to expect". The great majority of the posters here have utterly no comprehension of careful logical analysis of their own thoughts. Somehow their education has been sorely lacking.

Have fun -- Dick

 

[shrumeo]

Quote:
Originally Posted by Antonio Lao
To me the main purpose of science must be to answer the question "why?" All we been doing in science is answering the question "how?"


I think the discipline that answers the question WHY is called PHILOSOPHY.

Science can only answer HOW.

I sense things happening around me. What mechanism brought about these sensations? What caused them? How did it happen? What caused it and what caused that before it?

Science can only explain HOW nature works not WHY it does so.
(At least that's what I was taught in 6th grade.)