Teaching relativity to the general public

[David Cooper]

In the light of this policy https://www.physicsforums.com/threads/what-is-the-pfs-policy-on-lorentz-ether-theory-and-block-universe.772224/ , is it now considered acceptable to teach relativity by starting out with Lorentz Ether Theory (LET) and its Newtonian time which appears to be substantially easier for people to understand than the normal approach? The Internet is filled with confusing sites teaching relativity which categorically state that time is not Newtonian and which order the reader to start thinking about it in a radically different way, and yet it now seems that the more intuitive LET is considered to be the self-same theory as Einstein's, merely attaching a different philosophical interpretation to it. I have spent several years looking into this to try to find out how Lorentz's theory was disproved, and it has come as considerable surprise to me to find out that it is actually still standing, just hidden out of sight behind Einstein's version the theory.

During the course of my research, it has become clear to me that many of the usual claims made about relativity are actually just unbacked assertions associated with philosophical interpretations which have no actual support from experiments, so it now strikes me that it is highly unethical to teach them as if they are facts, and yet that is how they are taught almost everywhere I look. Given that professional physicists are "generally content with the minimal interpretation and uninterested in philosophical interpretations", would it not make sense for everyone who introduces people to the subject to switch now to the simpler philisophical interpretation which doesn't require people to deal with a radically different nature of time (which most people never manage to get their heads around). Clearly it would still be wrong to provide only one of the philosophical interpretations or to assert that that approach is correct while failing to teach the other main interpretation, so it would be essential to teach both in order to ensure that the teaching is thorough and balanced.

What do people think about this?

(Please try not to turn it into an argument about which interpretation is best as an explanation of reality - this should be kept tightly focussed on education.)

 

[Khashishi]

I don't think it is advantageous to teach LET to students, since almost all literature covers SR, and this will just present mixed messages.

Secondly, SR is more minimal than LET, so your argument is backwards.

 

[David Cooper]

I don't think it is advantageous to teach LET to students, since almost all literature covers SR, and this will just present mixed messages.

I was thinking mainly about the general reader rather than a student of physics.

Secondly, SR is more minimal than LET, so your argument is backwards.

I can't see how it's more minimal when it involves greater complications when teaching it and leaves many people unable to get their heads round the subject at all. Surely the aim should not be to remain shackled to existing teaching approaches which fail many people and to try to make the subject more accessible.

 

[Khashishi]

I don't believe many students who are confused by SR will find LET any more understandable. You are assuming this to be true. On what basis?

SR generalizes to general relativity much more easily than LET. It is unavoidable to get into geometry when it comes to general relativity, and Lorentz transformations are just coordinate rotations in a curved spacetime. It is not clear how ether behaves with gravity.

 

[David Cooper]

I don't believe many students who are confused by SR will find LET any more understandable. You are assuming this to be true. On what basis?

I find that many people simply can't get past their own philosophical objections - they tend to reject special relativity out of hand on the basis that it makes no sense to them. They then give up on it altogether, and that's a shame when they could have learned a considerable amount through the LET approach (covering time dilation, length contraction and the headlights effect while exploring simple, rational mechanisms by which these things could occur), and that would have taken them to the point where they could then have gone on to learn SR without the same hostile incredulity about the basic facts as to how things behave in space, and then they would have found it easy to go on from there to look at GR.

SR generalizes to general relativity much more easily than LET. It is unavoidable to get into geometry when it comes to general relativity, and Lorentz transformations are just coordinate rotations in a curved spacetime. It is not clear how ether behaves with gravity.

That may well be true - I haven't looked in detail at how LET handles gravity yet, but then there's a dearth of good reading material on that subject at the moment and I can only find explanations of GR.

 

[PeterDonis]

In the light of this policy https://www.physicsforums.com/threads/what-is-the-pfs-policy-on-lorentz-ether-theory-and-block-universe.772224/ , is it now considered acceptable to teach relativity by starting out with Lorentz Ether Theory (LET) and its Newtonian time which appears to be substantially easier for people to understand than the normal approach?

PF's policy has nothing to do with how it is or is not considered "acceptable" to teach relavity. PF's policy is solely concerned with what topics of discussion are acceptable here on PF. The purpose of the policy is to avoid having long discussions about things that cannot be resolved in this forum.

 

[PeterDonis]

I have moved this thread to the education forum since, per the OP, it is intended to be a discussion of how to teach relativity.

 

[David Cooper]

While it makes some sense to put it in this forum, sadly it also means there are unlikely to be any more useful replies as it is now in a section which the people whose advice I was seeking are unlikely to visit. That means I may now be forced to make important decisions without getting the input of the most qualified people available here, and the consequence may be that a government will make a switch to introducing relativity in schools through the LET approach.

 

[Khashishi]

You should be aware that Lorentz praised Einstein's work. He abandoned his own ether theory after subsequent work by Poincare and Einstein.

 

[wabbit]

I would just say that to me as a layman the most interesting thing in SR is relativity itself (of time, space, etc). I'd feel cheated if taught LET, or most likely I wouldn't have gone past the first two pages of a book that taught that at the time I was first exposed to SR, as it would have looked like a bunch of obscure formulas for specialists who need to work with high velocity situations, something I had no particular interest in. Add to that an arbitrary undetectable ether and the book would have hit the dustbin:) On the other hand SR was immediately interesting precisely because it questionned the notions of absolute time and space and explored the idea of relativity and more generally a relational view of space and time. This is just a personnal view but the reason I m interested in physics as a layman is the ideas, not the formulas.

 

[PeterDonis]

I may now be forced to make important decisions

Your OP said nothing about "making important decisions". In any case, PF is not in the business of making decision recommendations.

the consequence may be that a government will make a switch to introducing relativity in schools through the LET approach

Do you consider that a good thing or a bad thing? From your OP it would seem that you consider it to be a good thing since you believe it would be simpler and more intuitive.

The other obvious question, if this is really about how SR is going to be taught in schools, aren't there standard textbooks in the field? For example, Taylor & Wheeler's Spacetime Physics? Is there some issue with just using those? From what you're describing, it seems like you think there are no resources out there and you're having to make up your own teaching materials. That does not seem plausible to me.

 

[PeterDonis]

During the course of my research, it has become clear to me that many of the usual claims made about relativity are actually just unbacked assertions associated with philosophical interpretations which have no actual support from experiments

This statement, and others in your post, make me think you either have not looked at, or have not understood, standard textbooks in the field, such as the one I mentioned in my previous post. If you are trying to put together a curriculum for teaching SR in schools, you should not be using random things you find on the Internet. Physicists who are experts in this field have spent years putting together textbooks for the express purpose of teaching SR. Those are what you should be using.

Some other good references by experts are listed here:

http://math.ucr.edu/home/baez/physics/Administrivia/booklist.html#special-relativity

 

[wabbit]

Regarding your statement that it might be unethical to teach SR as fact.

This does sounds a bit strong to me - I don't expect a teacher at an introductory level to start with a long explanation about what the limits of the theory he is going to present are, and which parts should be regarded as interpretative etc - I'm happy to learn the basics first and get the provisos afterwards or for question time, and wouldn't complain about unethical behavior there.

But mostly, if this is so, then teaching LET surely is just as unethical for the same reason ? Or do you feel compelled to teach both at the same time?

And finally surely there's nothing wrong with presenting SR by saying "and it turns out that if we drop the assumption that... and intead make the assumption that ... then everything suddenly looks simpler and more natural", which is by the way more or less how I remember it being presented.

 

[PeterDonis]

it now strikes me that it is highly unethical to teach them as if they are facts

I think it would behoove you to check into SR's experimental support (which is quite extensive) before making hasty judgments about what should or should not be taught as fact. Once again, you should not be using random sources on the Internet to decide how to teach SR. You should be using the best efforts of experts in the field.

 

[Nugatory]

That means I may now be forced to make important decisions without getting the input of the most qualified people available here, and the consequence may be that a government will make a switch to introducing relativity in schools through the LET approach.

Are you saying that input (or lack thereof) from an anonymous Internet forum might be the basis for a decision to make such a switch?

 

[PeterDonis]

I was thinking mainly about the general reader rather than a student of physics.

I find this statement a bit puzzling in view of your post #8. Are we just talking about SR for the general reader, or are we talking about actual schools and school curricula?

 

[Nugatory]

During the course of my research, it has become clear to me that many of the usual claims made about relativity are actually just unbacked assertions associated with philosophical interpretations which have no actual support from experiments

An example of such a claim would help us understand the sorts of things that you see as problems in need of correction.

 

[Wes Tausend]

In my opinion, one of the best brief information sources regarding Lorentz, Einstein's SR and Poincaré, is this short, animated, 1/2 hour video called The Lorentz Transformation from Annenberg Media. Scroll down and click on #42, accept the pop-up and it should load. Similar videos have also appeared on PBS TV extra channels in my area.

It does seem that the OP may not be familar with the logical reasoning behind SR, and this CIT produced presentation should help. In addition, all these video series are suitable for high-school and introductory college classes. The one downside is that the programs are only downloadable in the USA and Canada. I haven't viewed them all, but, again, I suspect all the other of the 52 video physics series are also quite good.

Wes
...

 

[atyy]

In the light of this policy https://www.physicsforums.com/threa...rentz-ether-theory-and-block-universe.772224/ , is it now considered acceptable to teach relativity by starting out with Lorentz Ether Theory (LET) and its Newtonian time which appears to be substantially easier for people to understand than the normal approach?

Yes. See Bell's "How to Teach Special Relativity" reprinted in https://www.amazon.com/dp/0521368693/?tag=pfamazon01-20. Rindler also comments https://www.amazon.com/dp/0198567324/?tag=pfamazon01-20 (p43) that "in SR every inertial frame is as good as absolute space". From LET one can derive Minkowski spacetime, and from Minkowski spacetime one can derive LET. In classical physics, they are the same theory.

The situation is a bit delicate in quantum mechanics, and one can see "Bell's theorem" for discussions. I believe the physics is correctly discussed in these papers, but there is a debate nonetheless about the interpretation of history.
http://arxiv.org/abs/1402.0351
http://arxiv.org/abs/1503.05017
http://arxiv.org/abs/1503.06978
http://arxiv.org/abs/1311.6852
http://arxiv.org/abs/1503.06413

 

[wabbit]

Yes. See Bell's "How to Teach Special Relativity" reprinted in https://www.amazon.com/dp/0521368693/?tag=pfamazon01-20. Rindler also comments https://www.amazon.com/dp/0198567324/?tag=pfamazon01-20 (p43) that "in SR every inertial frame is as good as absolute space".

Yes but isn't that missing the point ? Who is being taught here and to what purpose ? What makes it worthwile to teach LET rather than SR ? So far the argument has been that it's easier - but is this true of the students, or is the problem with the teacher ?

 

[atyy]

Yes but isn't that missing the point ? Who is being taught here and to what purpose ? What makes it worthwile to teach LET rather than SR ? So far the argument has been that it's easier - but is this true of the students, or is the problem with the teacher ?

I added some comments about quantum mechanics to my post above :)

One more paper about quantum mechanics and LET/Minkowski: http://arxiv.org/abs/1111.1425.

 

[David Cooper]

You should be aware that Lorentz praised Einstein's work. He abandoned his own ether theory after subsequent work by Poincare and Einstein.

Lotentz perhaps wasn't as bright as Einstein and he missed a few tricks, such as the way to show that there's nothing ad hoc about length contraction in LET. He gave up on something that turned out to be easy to show.

I would just say that to me as a layman the most interesting thing in SR is relativity itself (of time, space, etc). I'd feel cheated if taught LET, or most likely I wouldn't have gone past the first two pages of a book that taught that at the time I was first exposed to SR, as it would have looked like a bunch of obscure formulas for specialists who need to work with high velocity situations, something I had no particular interest in.

That shows that you don't know how LET can be taught. It can all be done by using a computer screen to represent the fabric of space with pulses of light always moving across it at a fixed speed. When you do that you can easily show why time dilates in the way it does and why length must contract too (not to force things to fit in with the results of experiments like MM, but for a mechanistic reason). When you draw out the light paths it's then easy to do the maths using trigonometry to work out the slowing of clocks and the degree of length contraction for any speed of travel through the space fabric. It is the clearest possible way to introduce the subject and to make it obvious to all the leraners that these effects must happen. The normal SR explanation is much harder to follow, but it most certainly does need to be taught as well.

Add to that an arbitrary undetectable ether and the book would have hit the dustbin:)

The arguments against the idea of a fabric of space and an absolute frame of reference cause many people to throw the whole idea of relativity in the dustbin because it conflicts with their ideas of how nature works. As soon as you tell them that there is no absolute frame at all (not even an undetectable one) they think you are asking them to believe in contradictions - the accounts of events from different frames directly contradict each other and cannot all be true (in one frame of reference, rocket A accelerates away from rocket B and the ticking of its clock slows down, but in another frame of reference the ticking of its clock speeds up instead - it is not possible for both of these things to happen at the same time). However, they are usually thinking in LET-like ways with a Newtonian time when they apply these objections. When they think it through with time turned into a dimension, they then run into a similar issue where rocket A accelerates away from rocket B and ends up taking a shorter path into the future when you do the analysis from one frame of reference while if you analyse events from another frame of reference you find that it takes a longer path then rocket B instead, so there is still an nasty contradiction there which for philosophical reasons (i.e. logical/mathematical) they cannot accept - they think there must be a special frame in which the longest path into the future is available. All interpretations run into a version of the same issue in one way or another.

On the other hand SR was immediately interesting precisely because it questionned the notions of absolute time and space and explored the idea of relativity and more generally a relational view of space and time. This is just a personnal view but the reason I m interested in physics as a layman is the ideas, not the formulas.

You're right about that being interesting, and there is no question that SR must be taught too. I think it's doubly interesting to look at both sides of the argument though and not just to teach one.

Your OP said nothing about "making important decisions". In any case, PF is not in the business of making decision recommendations.

I'm connected with a political party which is exploring the idea of radical education reform - there is a package of software under construction, but I cannot say more than that, although introducing relativity in primary schools would be very much on the table.

Do you consider that [teaching LET in schools] a good thing or a bad thing? From your OP it would seem that you consider it to be a good thing since you believe it would be simpler and more intuitive.

Having looked at it carefully, I do think it would be a good thing, but I'm looking to see what objections there might be to it from the physics world in general, and the best talent at the top physics forums deserve to have a chance to have their say.

The other obvious question, if this is really about how SR is going to be taught in schools, is, aren't there standard textbooks in the field? For example, Taylor & Wheeler's Spacetime Physics? Is there some issue with just using those? From what you're describing, it seems like you think there are no resources out there and you're having to make up your own teaching materials. That does not seem plausible to me.

The approach in all the existing books I've looked at has a common problem - a complete failure to address the philosophical objections to SR, and it's that that leaves many learners looking on relativity as witchcraft. As for finding a book for schools teaching LET, that's a tall order, but there is some superb software under development for this. In general though, almost all the teaching materials currently used in schools fall a long way short of where they should be - there is a continual need to replace almost all of it with new materials which are clearer, more comprehensive, and they should also be optimised for self-teaching. That really means a shift to interactive computer programs, but the most important thing is to get the content right and in the case of science to make it absolutely clear what is fact and what is mere assertion. Far too many people are being taught to believe in philosophical baggage that is not backed by experiment, and that's doing science a disservice.

This statement, and others in your post, make me think you either have not looked at, or have not understood, standard textbooks in the field, such as the one I mentioned in my previous post. If you are trying to put together a curriculum for teaching SR in schools, you should not be using random things you find on the Internet. Physicists who are experts in this field have spent years putting together textbooks for the express purpose of teaching SR. Those are what you should be using.

There is no question of just cobbling together random things found on the Internet. The plan is to put together the best package possible, learning from everything that has been done before. The current approach is clearly failing because it generates swarms of qualified people who believe some of what is merely philosophical baggage to be fact even though it has no experimental backing. That is unethical and it must be stopped - it is a sign of education failure.

Some other good references by experts are listed here:

http://math.ucr.edu/home/baez/physics/Administrivia/booklist.html#special-relativity

Thanks - I will check them all.

Regarding your statement that it might be unethical to teach SR as fact.

This does sounds a bit strong to me - I don't expect a teacher at an introductory level to start with a long explanation about what the limits of the theory he is going to present are, and which parts should be regarded as interpretative etc - I'm happy to learn the basics first and get the provisos afterwards or for question time, and wouldn't complain about unethical behavior there.

Any teaching materials which assert that time is not Newtonian or that there is no absolute frame of reference are passing off assertions as facts. I've found university textbooks making highly misleading claims which help to fix ideas firmly in people's heads in the fact compartment even though they are just assertions. Misleading claims should have no place in education. Most importantly though, even if you use textbooks which never overstep the mark in any way, you still need to be aware that the learner will be encountering information from many other sources which will likely push them into believing that various key assertions are facts, and that needs to be countered actively by arming them with an understanding of which parts of SR are merely assertions (i.e. philosophical interpretations). The most powerful way to do that would be to teach them about LET too so that they can see a viable alternative interpretation of what is officially regarded as the same theory, and then any assertion which conflicts with LET will be immediately recognisable as assertion rather than fact.

But mostly, if this is so, then teaching LET surely is just as unethical for the same reason ? Or do you feel compelled to teach both at the same time?

Both should be taught, and in each case the assertions tacked onto them must be labelled clearly as assertions.

And finally surely there's nothing wrong with presenting SR by saying "and it turns out that if we drop the assumption that... and intead make the assumption that ... then everything suddenly looks simpler and more natural", which is by the way more or less how I remember it being presented.

That is something that should certainly be done with the assertion that there is no special frame in SR (similar to the absolute frame in LET) - if the idea that there could be a special frame is discussed (and the assertion that there isn't one is correctly identified as a mere assertion), the objections based on contradictions (in the accounts generated by the analysis done from different frames) are wiped away at a stroke and the SR/GR models are not damaged by that at all. It's when you do that that the disbelievers suddenly begin to open the door to SR and regard it as potentially viable instead of something that defies reason.

I think it would behoove you to check into SR's experimental support (which is quite extensive) before making hasty judgments about what should or should not be taught as fact.

There is no experimental evidence that there is no absolute frame. There is no experimental evidence that time is not Newtonian. There is no experimental evidence that the speed of light is the same relative to you in all directions. Many assertions are pushed as if they are facts, and for every source of information that frames its claims with greater care, there are a hundred others which don't. By teaching LET in addition to SR, you arm the learner against being misled by the bombardment of false claims which they will inevitably encounter. The most damaging source of misinformation is the TV science documentary where professional physicists overstate the case time and time again, pushing assertions as facts. Education needs to counter that by arming learners with sufficient knowledge to be able to tell when the truth is being simplified out of something or when a physicist is merely pushing a philosophical interpretation.

Once again, you should not be using random sources on the Internet to decide how to teach SR. You should be using the best efforts of experts in the field.

One has to look at the whole picture and cover all the most important sources. If you think asking the opinion of people here is not a good idea, then I cannot agree with you. I have already found it useful to hear the various objections/comments.

Are you saying that input (or lack thereof) from an anonymous Internet forum might be the basis for a decision to make such a switch?

It is an opportunity for people to have their say. I am leaning towards going with LET as an introduction to relativity, so I'm looking to see if anyone can provide good reasons why this should not be done.

I find this statement a bit puzzling in view of your post #8. Are we just talking about SR for the general reader, or are we talking about actual schools and school curricula?

Children do not all go on to be physicists, but they do grow up to be adult members of the general public with all manner of ideas and beliefs stamped into their heads from their upbringing. Many of them then frequent science forums as members of the general public who have an interest in science and who believe they have a little knowledge too. They then push assertions as if they are facts, piling in against anyone who questions any of their learned beliefs, and this shuts down rational discussion.

An example of such a claim would help us understand the sorts of things that you see as problems in need of correction.

Einstein's assertion that there is no absolute frame of reference is a prime example - that is just his philosophical interpretation and not a fact, but it is pushed almost everywhere as if it is a fact.

In my opinion, one of the best brief information sources regarding Lorentz, Einstein's SR and Poincaré, is this short, animated, 1/2 hour video called The Lorentz Transformation from Annenberg Media. Scroll down and click on #42, accept the pop-up and it should load. Similar videos have also appeared on PBS TV extra channels in my area.

Thanks - I'll have a look at that.

It does seem that the OP may not be familar with the logical reasoning behind SR, and this CIT produced presentation should help.

As someone who works in AGI system development, I specialise in logical reasoning (and linguistics). I will not discuss the role of this in education, but there is a link. I have explored the logical reasoning behind SR with extreme care and have only found two issues with it, one of which can be eliminated easily by recognising the logical need for a special frame of reference (which can't be identified) in any interpretation of SR. The other issue relates to the role of cause and effect in a universe where a photon can jump billions of years into the futrue in zero time and find the future fully built for it without having to wait for that time-section of the universe to be generated from the earlier part over billions of years, but that is only a problem for the block universe interpretation of SR and need not damage SR itself. Again it is important to provide a robust education into the different interpretations because so many physicists appear on TV asserting that gravity is not a force (rather than stating that it may not be and that it depends on a particular interpretation of SR being correct), and as soon as you try to eliminate it as a force you are taken into the block universe model where all causation is eliminated and replaced with lucky accident.

Yes. See Bell's "How to Teach Special Relativity" reprinted in https://www.amazon.com/dp/0521368693/?tag=pfamazon01-20. Rindler also comments https://www.amazon.com/dp/0198567324/?tag=pfamazon01-20 (p43) that "in SR every inertial frame is as good as absolute space". From LET one can derive Minkowski spacetime, and from Minkowski spacetime one can derive LET. In classical physics, they are the same theory.

The situation is a bit delicate in quantum mechanics, and one can see "Bell's theorem" for discussions. I believe the physics is correctly discussed in these papers, but there is a debate nonetheless about the interpretation of history.
http://arxiv.org/abs/1402.0351
http://arxiv.org/abs/1503.05017
http://arxiv.org/abs/1503.06978
http://arxiv.org/abs/1311.6852
http://arxiv.org/abs/1503.06413

Thanks - I'll look into all of those.

Yes but isn't that missing the point ? Who is being taught here and to what purpose ? What makes it worthwile to teach LET rather than SR ? So far the argument has been that it's easier - but is this true of the students, or is the problem with the teacher ?

I think it's an easier way into the subject, but more importantly it arms the learner against the avalanche of misinformation which they will encounter later on. As it stands, most people (including large numbers of professional physicists) have mistaken assertions for facts and learned them as such. In doing so, they have created a climate in which an alternative interpretation which is still fully viable is being treated as if it doesn't exist, generally considered to be obsolete or disproven. That is not something which real education should be playing along with because it would be to provide a distortion of the truth. There is certainly no need to go the other way and spend hundreds of hours exploring LET, but two or three hours spent on it right at the start could make a huge positive difference, showing everyone that relativity is not some kind of magic which can't be visualised easily, but that it's an obvious (once you've seen it) reality.

 

[wabbit]

That shows that you don't know how LET can be taught.

Honestly, I don't really care how it's taught, my point is whether it's something useful or interesting to learn early on.

The normal SR explanation is much harder to follow, but it most certainly does need to be taught as well.

Yes, you can learn the Lorentz transform without the need for any deep thinking, though at the cost of accepting some rather unnatural if not bizarre explanations. But to what purpose ? Aside from SR, I see the Lorentz transform as a specialized tool for dealing with high velocities. What is the value of teaching it to a general audience?

And since you agree that SR needs to be taught, then why not just do it instead of teaching the two ?

Again, I don't see the value of teaching LET except later in the process - both for its historical interest, and because by stressing that we can pick any frame and declare it absolute, this can enrich the understanding one has of SR. So in my view LET is an interesting topic for advanced students, while SR is essential much earlier.

 

[wabbit]

As soon as you tell them that there is no absolute frame at all (not even an undetectable one) they think you are asking them to believe in contradictions

You have a point, though I would think a better solution to that would be to teach with a view of relativity earlier. Absolute space is an unnatural concept which has no basis in common experience, and I believe is only acquired because it is taught. Avoid teaching that bizarre idea, and people will find it much easier to forget it later and integrate also relativity of space and time.

Regarding your comment that there is no proof of no absolute space - of course not, but that is not the point. There is ample evidence of space as a relational phenomenon, i.e. of relative space. Absolute space is just a possible hypothetical entity one can add if one likes, with no evidence making it necessary. We can add many other hypothetical entities that do not break the models, but these only distract from what matters.

 

[David Cooper]

Honestly, I don't really care how it's taught, my point is whether it's something useful or interesting to learn early on.

If you teach it the right way, it's extremely interesting and useful, providing a direct understanding of why things like time dilation and length contraction must happen right at the start.

Yes, you can learn the Lorentz transform without the need for any deep thinking, though at the cost of accepting some rather unnatural if not bizarre explanations. But to what purpose ? Aside from SR, I see the Lorentz transform as a specialized tool for dealing with high velocities. What is the value of teaching it to a general audience?

The idea is to teach it initially without using the Lorentz transform - there is a much simpler way to explore it.

And since you agree that SR needs to be taught, then why not just do it instead of teaching the two ?

Because the way the LET model would be taught is much simpler and clearer.

Again, I don't see the value of teaching LET except later in the process - both for its historical interest, and because by stressing that we can pick any frame and declare it absolute, this can enrich the understanding one has of SR. So in my view LET is an interesting topic for advanced students, while SR is essential much earlier.

Declaring it absolute is not a good idea, but treating it as if it is absolute is fine.

You have a point, though I would think a better solution to that would be to teach with a view of relativity earlier. Absolute space is an unnatural concept which has no basis in common experience, and I believe is only acquired because it is taught. Avoid teaching that bizarre idea, and people will find it much easier to forget it later and integrate also relativity of time.

Absolute space is a natural concept which young children automatically think up for themselves. Initially they think the Earth is anchored to it, but later they determine that the Earth is rotating and moving through it instead. Then they are taught about relativity and they have assertions pushed at them which many of them don't feel make sense. I think a better way to deal with this is to start with LET which makes immediate sense to them, and then to introduce SR and to look at the issue of absolute space there, at which point you need to explain that a lot of the baggage attached to SR is just assertion and that it does not need to be accepted in order to get a working understanding of the model. Your idea of trying to hide the idea of absolute space from them is actually just you trying to impose a philosophical interpretation upon them by avoiding looking at a philosophical interpretation which you disagree with. To do that would would be to distort their education.

 

[wabbit]

Absolute space is a natural concept which young children automatically think up for themselves

That's interesting. Surely they first acquire a concept of spatial relations before a concept of space though ? At what stage of development does this idea of absolute space cristallize ? They must also be inclined to drop it once they discover that the Earth rotates, or that it moves relative to the Sun, so if they acquire an early idea of absolute space, that would be a good time to dispel that illusion.

 

[Khashishi]

Why should a political party have any say in how we teach science?

Anyways, you asked here to figure out what people thought. Now how are you going to weigh your own personal (ungrounded) convictions against the responses?

Basically, LET is kind of like geocentrism. It wasn't flawed because the model didn't work. It was flawed because it proposes that the Earth's frame of reference is more special than every other one, and it didn't generalize.
How do you teach that a special frame of reference exists if you don't even know what that special frame is? Do you just assert that the cosmic microwave background is at rest? I'm serious, let's say you teach this ether theory, and then you give a homework problem to calculate the local time on spaceship A when it receives a signal from B. How would you even answer this question? It's easy to imagine the concept of an absolute rest frame, but then you actually try and calculate, and you realize since you don't know what it is, it's completely worthless in your calculations. Or worse, you do know what it is, and suddenly, your equations become much harder than necessary.

A simple question: what does B's clock say when A's clock reads t0?
Now, it's easy to calculate with SR, but I'm a student that was taught LET, so I start thinking about how fast B is moving relative to the ether so I can calculate the local time on B. Then the same for A. Then do some kind of comparison between the two local times. Wow, way more work, since now you need to calculate a third frame of reference.

You'll say, no, we'll teach the concept of LET, but actually do calculations just like in SR. Well what's the point of that? By the time you teach kids that it doesn't matter what you use as the absolute reference frame and we have no way of actually knowing what that frame really is, then the whole thing just becomes silly.

Suppose we discover a way to measure the ether. It is moving at 0.8443c, at some angle that uses astronomer's coordinates. LET is proven true. Guess what? We'll still teach people SR since the LET way of calculating the simple problems is way harder. I mean, seriously, forcing yourself to calculate in some weird arbitrary coordinates...

 

[PeterDonis]

they then run into a similar issue where rocket A accelerates away from rocket B and ends up taking a shorter path into the future when you do the analysis from one frame of reference while if you analyse events from another frame of reference you find that it takes a longer path then rocket B instead

If this is what comes out of your analysis then your analysis is incorrect. A correct analysis will show that the proper time elapsed for rocket A is shorter than the proper time elapsed for rocket B when calculated in any frame. Obviously you should not be teaching incorrect methods of analysis.

There is no experimental evidence that there is no absolute frame.

There is also no experimental evidence that there is an absolute frame. In the absence of evidence either way, the simpler model, which is standard SR with no absolute frame, is preferred by Occam's razor.

There is no experimental evidence that time is not Newtonian.

I don't know what you mean by "time is not Newtonian". If you mean that there is no experimental evidence that objects taking different paths through spacetime between the same events can have different elapsed times, you are egregiously wrong. See here:

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#Twin_paradox

There is no experimental evidence that the speed of light is the same relative to you in all directions.

Here again, you are egregiously wrong. See here:

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#round-trip_tests

Many assertions are pushed as if they are facts

None of the ones you have given so far are valid examples of this. Do you have any others?

The most damaging source of misinformation is the TV science documentary where professional physicists overstate the case time and time again, pushing assertions as facts

I am actually sympathetic to this claim, because I often see physicists on TV specials failing to distinguish between well-established facts, theoretical deductions which are highly likely to be right but do not yet have strong experimental confirmation, and just plain speculation. We also get frequent threads here on PF where posters have misconceptions about relativity (and quantum mechanics, and other areas of physics) spawned by such TV specials (Brian Greene's specials in particular seem to be a frequent source of these).

However, I do not see how your proposal, which is basically to teach multiple interpretations instead of just one, helps with this. The problem is not that only one interpretation is taught; the problem is that any interpretation is taught. In my opinion, the best antidote to interpretations is to teach students that you can do physics with no interpretation at all, i.e., with nothing more than equations, operational definitions of what the quantities in the equations mean, and experimental results. That has the added benefit of forcing students to clearly distinguish those things from all the extra baggage that comes along with an interpretation.

For example, in my comment above about "time is not Newtonian", I very carefully phrased what we do have abundant evidence about: "objects taking different paths through spacetime between the same events can have different elapsed times". That is an experimentally demonstrated fact. Different "interpretations" may offer different explanations of why this fact is true--one may say it's "time dilation", another may say it's "different speed relative to the ether", etc., etc. But you can derive the prediction from theory, do the experiment, and compare the results with the prediction without any "interpretation" at all, beyond what is minimally necessary to know how you get "different elapsed times between the same events" from the experimental data, i.e., the operational definition of what the quantity "proper time" in the theoretical model means.

They then push assertions as if they are facts, piling in against anyone who questions any of their learned beliefs, and this shuts down rational discussion.

We do our level best not to let this happen here on PF (I can't say what other forums are like). But you have to understand that LET, itself, is one of the things people come here trying to push assertions about as if they are facts. Part of the reason we have a strict rule about LET threads here is precisely that such threads almost always turn into nothing but repeated assertions back and forth. We have concluded that the reason for this is that you can't distinguish between different "interpretations" of the same physical theory by experiment, so there is no answer to the question of which interpretation is "right". To us, that means "interpretations" are philosophy, not physics, and we find that it works better to focus on the physics.

Einstein's assertion that there is no absolute frame of reference is a prime example - that is just his philosophical interpretation and not a fact

No, it is a fact; more precisely, what Einstein's assertion refers to is not the philosophical claim that "an absolute frame of reference is impossible because of the principle of relativity", or some such, but the experimental fact that we have no evidence that any particular frame is any different from any other. The same laws of physics work in all frames. An "absolute frame" would be a particular frame in which the laws of physics were different; but nobody has ever found such a frame.

If you say "well, we don't have any evidence that there isn't such a frame--it could be that there is one, it's just undetectable", then you are missing the point. An "absolute frame" that is undetectable because it doesn't affect any experimental results is no different, from a physics point of view, from no "absolute frame" at all. It's like Carl Sagan's invisible dragon in the garage.

a photon can jump billions of years into the futrue in zero time and find the future fully built for it without having to wait for that time-section of the universe to be generated from the earlier part over billions of years

This is also egregiously wrong. First of all, it is not correct to say that a photon has "zero time" along its path; the correct statement is that the concept of "elapsed time" is not well-defined for a photon. But if you want to object that this is just a quibble over terminology, your second statement illustrates why it isn't: the incorrect terminology has led you to draw an egregiously incorrect inference, that a photon somehow "jumps" over a huge part of the universe. A photon's worldline, even if it covers billions of years, still has to pass through every single point of spacetime along its path in between, and it has to respond to the causal influences present at each point, as those influences are generated from earlier points.

as soon as you try to eliminate it as a force you are taken into the block universe model where all causation is eliminated and replaced with lucky accident

I don't understand this at all; the block universe model is perfectly consistent with causality.

more importantly it arms the learner against the avalanche of misinformation which they will encounter later on

I'm sorry to be blunt, but so far the misinformation seems to be coming from you; you appear to have fundamental misunderstandings about relativity, both theoretical and experimental. I would not recommend making any decisions about how to teach SR based on what you think you know about it.

 

[PeterDonis]

a lot of the baggage attached to SR is just assertion and that it does not need to be accepted in order to get a working understanding of the model

You are focusing on SR here, but it's worth noting that, in the context of GR, where spacetime is curved, the notion of "absolute space" becomes much more problematic, because there are no longer any global inertial frames.

 

[atyy]

There is no experimental evidence that there is no absolute frame. There is no experimental evidence that time is not Newtonian. There is no experimental evidence that the speed of light is the same relative to you in all directions. Many assertions are pushed as if they are facts, and for every source of information that frames its claims with greater care, there are a hundred others which don't. By teaching LET in addition to SR, you arm the learner against being misled by the bombardment of false claims which they will inevitably encounter. The most damaging source of misinformation is the TV science documentary where professional physicists overstate the case time and time again, pushing assertions as facts. Education needs to counter that by arming learners with sufficient knowledge to be able to tell when the truth is being simplified out of something or when a physicist is merely pushing a philosophical interpretation.

I should make it clear that LET should not be taught in addition to SR. LET and Minkowski spacetime are two different ways of presenting SR.

What is meant by "there is no absolute frame" is the local laws of physics are Poincare invariant. This is a property of SR, and it is therefore a property of LET. No theory can ever be proven by experiment, but a theory can be shown to hold to extremely good approximation in some regime. Poincare invariance has survived all experimental tests to date.

http://arxiv.org/abs/0802.1561
Have we tested Lorentz invariance enough?
David Mattingly

 

[David Cooper]

[/QUOTE]Absolute space is just a possible hypothetical entity one can add if one likes, with no evidence making it necessary. We can add many other hypothetical entities that do not break the models, but these only distract from what matters.[/QUOTE]

Absolute space is something that comes in through reasoning and it is therefore part of a philosophical interpretation. It is also a philosophical claim when one attempts to rule it out on the basis of reasoning. Which opinion of either is actually backed by reason is another issue which need only be explored by those who seek to understand reality through reasoning, and that is something that should be done when exploring different takes on a theory and examining the assertions they have tied to them. Reason backs the idea of an absolute frame in LET but conflicts with the idea of ruling out a special frame in SR, and it does it by looking at the contradictions generated by the accounts of events based on different frames of reference.

That's interesting. Surely they first acquire a concept of spatial relations before a concept of space though ? At what stage of development does this idea of absolute space cristallize ? I wonder how they figure what the absolute frame of reference is though or how fast they are moving relative to it.

It varies widely for different children, and some may never go in that direction at all. Indeed, it's possible that most of the people who go on to become physicists are the ones who never did look on the world that way and who were therefore more open to SR, not noticing the problem with the different accounts contradicting each other and therefore not all being true accounts. The rest may be repelled away from physics without discovering that the dogma about there being no special frame is just dogma and can be stripped away to leave a more rational model.

Why should a political party have any say in how we teach science?

All political parties should have a say in insisting that everything that is taught is taught in such as way that misinformation is not passed off as fact.

Anyways, you asked here to figure out what people thought. Now how are you going to weigh your own personal (ungrounded) convictions against the responses?

I look at the responses and weigh them up as impartially as I can. I attempt to judge things in the same way as an AGI system, simply identifying the facts and applying reason. I'm looking for any good objections which have not cropped up elsewhere or which have a stronger argument underlying them.

Basically, LET is kind of like geocentrism. It wasn't flawed because the model didn't work. It was flawed because it proposes that the Earth's frame of reference is more special than every other one, and it didn't generalize.

LET simply asserts that there is an absolute frame and then shows that even though only one frame can be that absolute frame, any frame can be treated as if it is that absolute frame and the maths will work out usefully, even if the accounts of events thus generated are not true.

How do you teach that a special frame of reference exists if you don't even know what that special frame is? Do you just assert that the cosmic microwave background is at rest?

When exploring the philosophical interpretations, you explain why an absolute frame is required in LET (and look at the similar issue in SR too). You then look at how it fits in with the expansion of space and determine that the absolute frame in one part of space cannot be the same as the absolute frame in every other part. The cosmic microwave background probably cannot be trusted to shed any light on the issue.

I'm serious, let's say you teach this ether theory, and then you give a homework problem to calculate the local time on spaceship A when it receives a signal from B. How would you even answer this question? It's easy to imagine the concept of an absolute rest frame, but then you actually try and calculate, and you realize since you don't know what it is, it's completely worthless in your calculations. Or worse, you do know what it is, and suddenly, your equations become much harder than necessary.

You can pick any frame and treat it as if it is the absolute frame even though it almost certainly isn't. There is no requirement to identify the absolute frame and use it in calculations.

A simple question: what does B's clock say when A's clock reads t0?
Now, it's easy to calculate with SR, but I'm a student that was taught LET, so I start thinking about how fast B is moving relative to the ether so I can calculate the local time on B. Then the same for A. Then do some kind of comparison between the two local times. Wow, way more work, since now you need to calculate a third frame of reference.

You're attacking a straw man.

You'll say, no, we'll teach the concept of LET, but actually do calculations just like in SR. Well what's the point of that? By the time you teach kids that it doesn't matter what you use as the absolute reference frame and we have no way of actually knowing what that frame really is, then the whole thing just becomes silly.

When you do the calculations in SR, you're doing them using a LET method. It is not difficult to understand that if the nature of reality hides from you the identity of the absolute frame by making all frames behave in such a way that they might be the absolute frame, then any frame can be used as if it is the absolute frame. At no point in that does it assert that any frame you like will actually be the absolute frame, and nor does it assert that there cannot be an absolute frame.

Suppose we discover a way to measure the ether. It is moving at 0.8443c, at some angle that uses astronomer's coordinates. LET is proven true. Guess what? We'll still teach people SR since the LET way of calculating the simple problems is way harder. I mean, seriously, forcing yourself to calculate in some weird arbitrary coordinates...

Of course we'll calculate things the most economical way. The important thing about education is that it should attempt to teach actual understanding (where that understanding is available) and not just supply people with methods for doing things. What it absolutely must not do is provide people with one explanation where there are two good ones available and make out that that one understanding is correct while any other that conflicts with it is wrong.

 

[wabbit]

You are focusing on SR here, but it's worth noting that, in the context of GR, where spacetime is curved, the notion of "absolute space" becomes much more problematic, because there are no longer any global inertial frames.

On the other hand there is cosmological time and its associated foliation, so unless. I'm missing something here a preferred frame emerges in our case. We could even add a comoving ether if we wanted : )

 

[wabbit]

Absolute space is something that comes in through reasoning and it is therefore part of a philosophical interpretation

Relative space also comes from philosophical reasoning, in fact it precedes absolute space in such reasoning because spatial relations are what any concept of space is built from.
I am not sure how widely the absolute space hypothesis was accepted by philosophers before Newton, but surely it wasn't a consensus.

 

[Niflheim]

Absolute space is something that comes in through reasoning and it is therefore part of a philosophical interpretation.

... Are you actually suggesting that a logically drawn conclusion is someone's opinion? Drawing conclusions through reasoning is perhaps the most important part of the scientific method! I understand that you think experiment should be used to justify a claim, but by your logic that wouldn't work either, since technically you are only reasoning that the experiment holds true outside of the literal exact context you performed it in.

 

[wabbit]

The important thing about education is that it should attempt to teach actual understanding (where that understanding is available)

Clearly your mind is set so there is not much point in this discussion, but I fail to see how teaching absolute space, i.e. an hypothetical entity for which there is neither proof nor necessity, furthers the goal of education any more than teaching that there is an army of invisible goblins floating in the ether that are under strict orders to never interact in any way with anything else so their presence cannot be detected even in principle.