Is Special Relativity Universally Accepted?

[Jimmy87]

Hi pf,

When I was taught about SR, I was told it was one of the most successful theories in science and has been verified over and over again. However, I have been watching some videos online and wanted some guidance. I initially came across this:

<link deleted>

This guy claims to have a PhD in physics but seems to talk complete nonsense in my opinion. He claims Einstein said that mass increases as your velocity increases near the speed of light. He then says the proof of Einstein being wrong is that all particle accelerators observe no mass increase. My understanding is that relativistic mass increases but this is not your true mass anyway so surely you should not observe any mass increase should you? What did Einstein actually say about mass and approaching light speed?

After reading through some of this guys threads, some people said that SR has been proved through muon decay, which I have studied a bit. His response to these comments is that this is not universally accepted and gave links to some other theory that can explain it (<link deleted>) and a video by a physics researcher that claims that time is invariant (unless you are accelerating):

<link deleted>

I just wanted to know if any current researching physicists debate whether or not SR is a complete theory? It frustrates me that if I came across people like this I wouldn't know what to say in response because we are never taught the extent to which these theories are tested and if there are any anomalies at all.

Thanks for any information given.

[Moderator's note: links to sites that are not acceptable sources per the PF rules have been deleted.]

 

[phinds]

Yes, SR is universally accepted and anyone saying it's wrong is full of crap.

 

[phyzguy]

Even the idea that the Earth is round is not "universally accepted". There are always nut jobs and crackpots. There is no debate among serious scientists on the validity of special relativity, but that does not stop the crackpots.

 

[phinds]

Even the idea that the Earth is round is not "universally accepted". There are always nut jobs and crackpots. There is no debate among serious scientists on the validity of special relativity, but that does not stop the crackpots.

Good point

 

[PeterDonis]

This guy claims to have a PhD in physics but seems to talk complete nonsense in my opinion.

Your opinion is correct.

He claims Einstein said that mass increases as your velocity increases near the speed of light. He then says the proof of Einstein being wrong is that all particle accelerators observe no mass increase.

He is confusing relativistic mass with rest mass. Relativistic mass was a commonly used concept in the early days of SR, which is why you will find Einstein and others, in those early days, saying that mass increases with velocity--they meant relativistic mass. But as time went on it became clear that this concept caused more problems than it solved, so it was abandoned. Modern treatments of SR use the term "mass" to mean rest mass. That's why modern particle accelerator experiments report no mass increase: the rest mass of the particles has not increased.

some people said that SR has been proved through muon decay, which I have studied a bit. His response to these comments is that this is not universally accepted and gave links to some other theory Tat can explain it

The link is to a crackpot site. Muon decay is perfectly consistent with SR; this has been established both by observing muons formed in the Earth's upper atmosphere by cosmic rays, and by observing muons in laboratories around the world.

I just wanted to know if any current researching physicists debate whether or not SR is a complete theory?

No reputable physicists doubt that SR is correct within its domain of validity. To be clear, though, that domain is limited: SR does not deal with cases where gravity is significant. So SR is not a "complete" theory in that sense; if gravity is significant, you have to use general relativity.

 

[PeterDonis]

Moderator's note: two off topic posts have been deleted. Posts that potentially violate the PF rules should be reported, not responded to.

 

[Jimmy87]

Moderator's note: two off topic posts have been deleted. Posts that potentially violate the PF rules should be reported, not responded to.

Sorry, I didn't realize. I truly apologise if I offended anyone. My intent was never by any means to support anything these people said (and I thought I made that clear). In fact it made me very angry when I came across these and was the reason for my post.

 

[Jimmy87]

Your opinion is correct.
He is confusing relativistic mass with rest mass. Relativistic mass was a commonly used concept in the early days of SR, which is why you will find Einstein and others, in those early days, saying that mass increases with velocity--they meant relativistic mass. But as time went on it became clear that this concept caused more problems than it solved, so it was abandoned. Modern treatments of SR use the term "mass" to mean rest mass. That's why modern particle accelerator experiments report no mass increase: the rest mass of the particles has not increased.
The link is to a crackpot site. Muon decay is perfectly consistent with SR; this has been established both by observing muons formed in the Earth's upper atmosphere by cosmic rays, and by observing muons in laboratories around the world.
No reputable physicists doubt that SR is correct within its domain of validity. To be clear, though, that domain is limited: SR does not deal with cases where gravity is significant. So SR is not a "complete" theory in that sense; if gravity is significant, you have to use general relativity.

What did Einstein actually say about mass and approaching the speed of light. Did he know that the true mass would stay as it was?

 

[Mister T]

When I was taught about SR, I was told it was one of the most successful theories in science and has been verified over and over again.

That's true, and you didn't mention the Global Positioning System. The engineers who synchronize the various clocks aboard satellites and on Earth must take SR as a fact. If they didn't the synchronization would be so far off that the GPS on your phone wouldn't be able to tell you what city you're in, but as it is it can tell you the street corner you're on.

Physics journal editors will tell you that they receive a steady stream of "proofs" that SR is wrong. Apparently it's a favorite among the crackpots, along with the 1st and 2nd Laws of Thermodynamics.

 

[PeterDonis]

What did Einstein actually say about mass and approaching the speed of light. Did he know that the true mass would stay as it was?

Einstein knew that rest mass (or "invariant mass"--the term "true mass" is not used) does not change with the speed of an object. I don't have any specific quotes of his about relativistic mass, but he knew that it was not the same as rest mass.

 

[Mister T]

He claims Einstein said that mass increases as your velocity increases near the speed of light. He then says the proof of Einstein being wrong is that all particle accelerators observe no mass increase.

There is a concept known as relativistic mass that increases with velocity, but Einstein was no fan of it. You can invent the concept of relativistic mass, and as a consequence of that invention claim that mass increases with speed. But the notion of mass increasing with speed is not a consequence of the postulates of SR. Time dilation, length contraction, and relative simultaneity are consequences of the postulates, consequences that have been verified quite extensively by experiment and observation.

Particle physicists do not use the concept of relativistic mass, so that explains the reason why they do not observe an increase in mass.

In the last 25 years or so the concept of relativistic mass has all but disappeared from the textbooks, it simply causes too much confusion, and the recently deceased Russian physicist Lev Okun was perhaps instrumental in providing the seed for that reform.

 

[pervect]

Hi pf,

When I was taught about SR, I was told it was one of the most successful theories in science and has been verified over and over again. However, I have been watching some videos online and wanted some guidance. I initially came across this:

<link deleted>

Professionally, special relativity is well accepted - accepted enough to be used as the fundamental definition of the SI meter. And you already know what your professor said.

From the National Institutes of Standards (NIST) website:

The definition of the meter (m), which is the international unit of length, was once defined by a physical artifact - two marks inscribes on a bar of platinum-iridium. Today, the meter (m) is defined in terms of constant of nature: the length of the path traveled by the light in vacuum during a time interval of 1/299, 792, 458 of a second. The Length - Evolution from Measurement Standard to a Fundamental Constant explains the evolution of the definition of the meter. Follow these changes over time in the https://www.nist.gov/node/433486.

You are possibly already quite familiar with SI units. I'll say a bit about the history of the SI system anyway, in case you are not familiar with them. An international body, the General Conference on Weights and Measures (the CGMP) was established in 1857, and the meter has evolved through a long history. At one point the meter t was defined by a physical artifact as the above quote mentions, but nowadays it's _defined_ based on how far light travels in a specified amount of time. I believe there was some interesting and famous discussions when the decision to make the switch was made, but I'm afraid I don't recall the details well enough to relate, and my sources on that might not be the best. (And a lot of the question here is about sources).

So, what you need to do is ask yourself. Who or what is the arbiter of what's "well accepted". Do you believe things you read by random, unknown posters on the world wide web, or do you believe your professor? How does your professor get his information? Does he read the WWW and tell you what the WWW says, or does he go to professional published peer-reviewed papers and well respected institutions?

More generally, does one determine what's "true" by taking an opinion poll? And if so, whom does one poll? Everyone? Or does one give more weight to some opinions than others? Is that approach (of finding truth by polling) even a good idea?

If you study the history of science more, you might decide that in order to determine what's true, it's a good idea to rely on experiment. But you still need to figure out what experiments you believe, and why. Unless you are in a position to personally perform such experiments as are necessary, I suppose, but that seems to be rather demanding (though it seems ideal). For instance, if you ran across this youtube video, <<link>> , should you believe it, or not? Who were the authors? Was it ever published in a peer reviewed paper? Do you trust them? Do the arguments it makes make sense to you?

There are certainly some interesting social phenomenon here. My take on it is that a lot of the objections to relativity come from people who don't understand it. I'm not quite sure why the objectors feel such a strong need to talk about things they apparently (in my opinion at least) don't understand. I can also add that I believe that the relativity of simultaneity is the usual stumbling block for understanding special relativity.

But if you're listening to the rest of what I said, you should realize that I'm just another voice on the WWW. Though naturally I believe that what I write is true - except when I make an unfortunate error. (It happens). In the end, you really need to learn about what sources are credible, and what sources are not, and why. Experience may help.

 

[Dale]

What did Einstein actually say about mass and approaching the speed of light. Did he know that the true mass would stay as it was?

That is more of a question of the changing usage of the word “mass”. As you probably already know, the meaning of a word varies over time.

There are several formulas in relativity where you find the expression $m\sqrt{1-v^2/c^2}$ in the place where you would expect to find $m$ from Newtonian physics. So in the early days of relativity people thought that it might be convenient to refer to this expression as “mass”.

However, there remain many places where $m$ appears without the factor $\sqrt{1-v^2/c^2}$, or with several of them, so calling it “mass” doesn’t help that much overall and the practice has fallen out of favor.

So where Einstein said $m\sqrt{1-v^2/c^2}$ he has been proven correct, regardless of whether he called it “mass” or not. Today we don’t call it “mass”, but that doesn’t make early authors wrong when they did. The usage of the word simply changed between then and now.

 

[mfb]

When I was taught about SR, I was told it was one of the most successful theories in science and has been verified over and over again.

I'm a particle physicist: We see the effects of special relativity directly in the accelerators and detectors all the time. None of these machines would work if any of the predictions of special relativity would be wrong. But it is much more than that. All of modern physics is based on special relativity. General relativity is a generalization that includes gravity, and quantum field theory is fully based on special relativity. Without special relativity, fundamental physics of the last 100 years wouldn't exist. None of the measurements that confirm general relativity and QFT over and over again would make sense. We couldn't have built atomic clocks, NMR scans wouldn't have a theoretical explanation, we wouldn't have an idea where antimatter came from, could not explain PET scans, wouldn't have an idea why radar works, couldn't calculate the Doppler effect seen in wireless communication, and so on. Special relativity is used everywhere.One of my favorite examples of precision measurements: There is a property called Lande-factor of the electron, and it can be both predicted and measured with extraordinary accuracy using quantum field theory. The theoretical prediction for its value is 2.002,319,304,363 where the last digit has an uncertainty of 2 (simplified: it should be in the range of 1 to 5, larger deviations are unlikely). The experimental measurement is 2.002,319,304,361,4 where the last digit has an uncertainty of 6.
The first 12 digits agree, and the deviation at the 13th (!) digit is of the size of the uncertainties of the prediction.

 

[Dale]

It frustrates me that if I came across people like this I wouldn't know what to say in response because we are never taught the extent to which these theories are tested and if there are any anomalies at all

You might want to read over this summary.

http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html

Occasionally crackpots will come up with an alternative that explains one or two experiments, but any alternative must explain all of these.

Note that there are continuing careful scientific experiments to detect ever smaller and smaller deviations from SR. A deviation in one of the Standard Model Extension parameters would give us a great clue about the direction that future theories need to take. None has been detected to date

 

[bhobba]

Science Adviser (yes he is one here - just does not post a lot) John Baez wrote an excellent article of relativistic mass etc:
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html

Well worth a read - it gets the concepts right.

Regarding the truth of SR we have derivations these days its very hard to ague with eg:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf

Of course in science correspondence with experiment is everything - and it has stood up to every test. However a derivation like the above shows if its wrong something rather drastic is incorrect with our understanding of things. It may be - but it would be a breakthrough in a sense if it happened - as Dale said.

Thanks
Bill

 

[bhobba]

Yes, SR is universally accepted and anyone saying it's wrong is full of crap.

I wouldn't say that. It has been tested to a high degree of accuracy, and we have derivations its very hard to argue with. I would say - as Issac Asimov said - extraordinary claims require extraordinary evidence. Although remembered as a science fiction writer he was also a professor of Biochemistry so knew his science.

Thanks
Bill

 

[vanhees71]

Einstein knew that rest mass (or "invariant mass"--the term "true mass" is not used) does not change with the speed of an object. I don't have any specific quotes of his about relativistic mass, but he knew that it was not the same as rest mass.

There's a very clear statement by Einstein in a private letter to use the invariant mass only since the concept of relativistic mass leads to confusion. The issue is very clearly analyzed in

L. B. Okun, The Concept of Mass, Physics Today 06/1989
https://doi.org/10.1063/1.881171

 

[Vanadium 50]

the meaning of a word varies over time.

Although in this case the time was very short - 1905 to 1908. The problem is that popularizations seem to have frozen at exactly this period.

 

[phinds]

I wouldn't say that. It has been tested to a high degree of accuracy, and we have derivations its very hard to argue with. I would say - as Issac Asimov said - extraordinary claims require extraordinary evidence. Although remembered as a science fiction writer he was also a professor of Biochemistry so knew his science.

Thansk
Bill

When I stated my belief that it is universally accepted I certainly did not mean to imply that it is utterly impossible for it to be wrong, just that, as you just stated, and as bhobba pointed out just above, it has fit all experiments exceptionally well and if it IS wrong there is some weird stuff going on that we don't understand.

 

[bhobba]

When I stated my belief that it is universally accepted I certainly did not mean to imply that it is utterly impossible for it to be wrong, just that, as you just stated, and as bhobba pointed out just above, it has fit all experiments exceptionally well and if it IS wrong there is some weird stuff going on that we don't understand.

I know exactly what you meant and personally would not have worried about it. But the OP is a beginner, and as one of my professors once said (he was the schools no 1 expert in analysis) you have your best professors teach the foundation subjects. The reason being getting things not quite exact at the start can do irreparable damage. More experienced students you don't have to be as careful with and using language like you did that was not quite precise is OK - in fact its done all the time - the people concerned know what you mean. Its just wise with 'newbies' to be more concise.

Don't worry about it - just keep in the back of your mind a bit of care with those less experienced is needed.

Thanks
Bill

 

[Mister T]

Although in this case the time was very short - 1905 to 1908. The problem is that popularizations seem to have frozen at exactly this period.

There were a lot of textbooks written after that that used the concept of relativistic mass, usually claiming that Einstein's 1905 theory predicted it and experiments confirmed it. It wasn't until the 1990's that those claims began to disappear. In the 1994 edition of Halliday and Resnick it wasn't even mentioned!

 

[vanhees71]

Well, there's a quite recent textbook in German (Rebhan, Theoretische Physik: Relativitätstheorie und Kosmologie) which all in all is quite good, but he insists on the relativstic mass :-((. He mentions that he was heavily critizised in a book review concerning this point, but he insists on the didactical value of the notion of relativistic mass. I can only disagree with him in this point, but as I said, that's however only one weak point (and favoring the Bohm interpretation of QM in the quantum-mechanics volume is another, although he does this also only in a separate chapter) of otherwise a very good theoretical-physics-book series.

 

[newjerseyrunner]

He then says the proof of Einstein being wrong is that all particle accelerators observe no mass increase.

That's just plain wrong. CERN wouldn't work if this were true.

Where did they say they got the PhD from? Trump University?

The old "trust me, I'm an expert in this," is the telltale lie of the bullshitter.

 

[mfb]

Rebhan

Born 1937. You know the saying how some things stop being used...

 

[Jimmy87]

That's just plain wrong. CERN wouldn't work if this were true.

Where did they say they got the PhD from? Trump University?

The old "trust me, I'm an expert in this," is the telltale lie of the bullshitter.

Wow, thanks to all for such an informative set of answers. You have all very kindly provided lots of extra reading into the history and validity of SR which is exactly what I wanted. I can't thank you all enough and I will definitely read over all the extra links/info provided. I have never come across crack pot scientists yet I can't quite get over how angry they made me feel. They were saying that professors know SR is wrong but they don't tell their students this otherwise they would have to scrap most of modern physics as it is based on SR like we are all leading some kind of lie in the science community. The reason it angered me so much is it doesn't matter how ugly the world is, science is always there as a saviour as it unites nations (regardless of political conflict) in an effort to explore the universe and advance our race. This is what I love about science. Maybe I was naive but I didn't think anyone on the planet could ever try and bring it into such awful disrepute. I almost think it is like trying to bring a charity into disrepute. They say it as though science is some belief system based on Einstein that we could never deviate from. As far as I am concerned if people did know it was wrong and had conclusive evidence they would become instantly famous. Science would never progress if it held onto incorrect theories on purpose. I understand some governments may be corrupt and there are benefits to them being corrupt but there is no benefit to corrupting science (not that I can see anyway). Again, I get why people may be suspicious of some governments because it is a fact of history that many governments have been and still are corrupt. But why the suspicion over science which has no history of corruption? If SR was wrong I don't see a SINGLE benefit to the science community in covering it up and holding onto it. In fact I see nothing but disadvantages. This is why I can't even understand the motive to do this in the first place.

Anyway sorry for going on too much. Newjerseyrunner could you explain your last post. I was under the impression this nut job was wrong because he doesn't even understand the current theory of SR. He said that Einstein (and SR) said that as you approach the speed of light your mass goes up. His "evidence" for SR being wrong is that particle accelerators observe no mass increase. As I understand it his "evidence" actually makes SR correct because SR (and Einstein) never said mass increases as you approach the speed of light. So particle accelerators should show no mass increase. Is what I said correct? Thanks again.

 

[PeterDonis]

I was under the impression this nut job was wrong because he doesn't even understand the current theory of SR.

I can't say what's going on in the nutjob's head, but, as I said in post #5, I think the basic confusion he is illustrating is failing to distinguish different possible meanings of the term "mass".

his "evidence" actually makes SR correct because SR (and Einstein) never said mass increases as you approach the speed of light.

SR and Einstein never said rest mass increases as you approach the speed of light; they have always said that rest mass is an invariant and doesn't change as speed changes. But as I said in post #5, in the early days of SR, the term "mass" could also be used to mean something called "relativistic mass" (which in modern terms is just the object's total energy in a particular frame, in mass units), and that does increase as speed increases (because total energy increases as speed increases); and Einstein knew that perfectly well.

So particle accelerators should show no mass increase.

Particle accelerators show no rest mass increase. And since the term "mass" is pretty much exclusively used to mean rest mass now, "no mass increase" means "no rest mass increase". But the energy of particles in accelerators certainly does increase, exactly as SR predicts, as the speed of the particles increases--in fact "speed" is not even measured in accelerators, energy is the key parameter, so much so that particle physicists routinely report even rest masses in energy units, for example when they say the Higgs boson mass is 125 GeV (that's giga-electron volts, an energy unit).

 

[PeterDonis]

Maybe I was naive but I didn't think anyone on the planet could ever try and bring it into such awful disrepute.

Unfortunately there are plenty of such people, many of whom even call themselves scientists and claim (and might even believe) that they are doing it "for the good of science".

Science would never progress if it held onto incorrect theories on purpose. I understand some governments may be corrupt and there are benefits to them being corrupt but there is no benefit to corrupting science (not that I can see anyway).

Unfortunately, if science and scientific findings are used as political tools, there can be a benefit--politically--to corrupting science. A historical example is Lysenkoist agriculture in the Soviet Union. But this is getting off topic; if there is a place at PF for a discussion of something like this, it's most likely the General Discussion forum.

 

[newjerseyrunner]

To expand on what I said about CERN. It’s particle accelerators work by creating an electromagnetic pulse that gives the projectiles a little push. These pulses have to be synced up so that they push the particles at exactly the right time, so you have to be able to calculate where they are going to be.

As you approach relativistic speeds (well within the capabilities of CERN) those pushes give each particle less speed because it’s harder to push. This has to be accounted for and is. If it wasn’t, the beam and the pulses would be out of sync.To address professors knowing SR is wrong: sort of? They know it’s a special case of general relativity: as in it doesn’t work in the real world because it doesn’t allow for acceleration. But teaching it is a required step to understand general relativity. Teachers teach Newtonian physics first, and that’s not necessarily wrong, just incomplete. If you want to be technical, GR still is incomplete and everyone knows that. People tend to cherry pick specific flaws in a theory in order to try and throw out the whole thing and that’s not how science works.

 

[jbriggs444]

To address professors knowing SR is wrong: sort of? They know it’s a special case of general relativity: as in it doesn’t work in the real world because it doesn’t allow for acceleration.

Special relativity handles most forces and the associated accelerations just fine. What it does not get right is gravitation as a force causing an acceleration.

 

[zonde]

Wow, thanks to all for such an informative set of answers. You have all very kindly provided lots of extra reading into the history and validity of SR which is exactly what I wanted. I can't thank you all enough and I will definitely read over all the extra links/info provided. I have never come across crack pot scientists yet I can't quite get over how angry they made me feel. They were saying that professors know SR is wrong but they don't tell their students this otherwise they would have to scrap most of modern physics as it is based on SR like we are all leading some kind of lie in the science community.

I would like provide a viewpoint from a bit different perspective in addition to valid and informative things others have said in this thread.
There is possible reason why such crack pots show up and keep spreading nonsense. The reason as I see it is that SR often comes with a bit of philosophy. That bit of philosophy is that inertial reference frames are fundamentally equivalent. That piece of philosophy is unacceptable for some (including me). But there are two things about it:
1. Even if you reject that, let me rather call it - interpretation, you still get the exactly the same physics. There is a term for this approach - Lorentz Relativity.
2. If people are incapable to separate interpretation from actual physics they might start to attack the physics because they wrongly perceive that actual physics depend on that interpretation while it does not.

I hope my explanation can help you reduce your emotions and help you defend physics better if you ever need to.

 

[NoTe]

inertial reference frames are fundamentally equivalent.

Reference https://www.physicsforums.com/threads/is-special-relativity-universally-accepted.935879/page-2: this is not philosophy, it is plain physics!

 

[NoTe]

Oops, something went wrong, #31 was meant as a reply to #30.

 

[zonde]

inertial reference frames are fundamentally equivalent.

Reference https://www.physicsforums.com/threads/is-special-relativity-universally-accepted.935879/page-2: this is not philosophy, it is plain physics!

How do you experimentally test the difference between fundamental equivalence and non fundamental equivalence?

 

[NoTe]

"How do you experimentally test the difference between fundamental equivalence and non fundamental equivalence?"

Equivalent just means that you cannot distinguish whether you are on the one or on the other, as an observer: you will find exactly the same laws of physics. This holds for all inertial reference frames. That's why the equivalence is physics and not philosophy. Does that answer your question? (P.S. I do not know what you mean by fundamentally equivalent, I would say equivalent is equivalent).