Light can't travel at the speed of light?

[FeDeX_LaTeX]

Hello;

For something to travel at the speed of light, mass has to be zero. Light is a form of electromagnetic radiation, which travels at 299,792,458 m/s. Because it is a form of electromagnetic radiation, it is carried by the force-carrier particle, the photon. However, photons have a very small mass that is almost zero (but not zero) so it is not massless, but very close to being massless. If light is simply photons, then that means that light cannot reach 299,792,458 m/s; in other words, light cannot reach the speed of light.

Where is the error here?

Thanks.

 

[Fightfish]

The error here, is that you are wrong in your thinking that photons "have a very small mass". Unfortunately, photons are massless. One can sometimes argue that we can assign a "moving mass" to photons, but at the end of the day, they have a rest mass of zero.

 

[FeDeX_LaTeX]

Why is their rest mass zero?

I thought photons were particles... how can a particle have no mass?

 

[luxiaolei]

Why is their rest mass zero?

I thought photons were particles... how can a particle have no mass?

Then, would you please explain what is mass?

 

[Fightfish]

Then I will pose the reverse question: why must a particle be massive? :p
According to commonly accepted consensus, well the answer is simply that it does not interact with the Higg's field, and thus does not acquire a mass.

 

[magnusrobot12]

photons do not have mass. photons is a "particle" representative of energy but it is massless just like a wave is massless.

 

[croghan27]

I am going to need some footnotes on this one!

"A photon is a particle that does not have a mass."
a) Does not the designation if it as a 'particle' imply it has a mass?
b) It interacts with the Higgs field. But, but, but the Higgs field/particle may or may not exist. Both are real possibilities - so where does that leave our little photon - still massless (or very small) and still zipping about at the speed of light. Yet if it is achieving the speed of light ... it cannot have a mass.

The rest mass is zero.
a) It only has mass while in motion?
b) Is there some kind of transformation associated with accel.. or decel - eration?

Are not photons particles, assuming a mass, when, as per Heisenberg, they are measured?

Help! Help! Help! I am trying hard not to make a pun about how I cannot see it.

 

[diazona]

I am going to need some footnotes on this one!

"A photon is a particle that does not have a mass."
a) Does not the designation if it as a 'particle' imply it has a mass?

Nope. Not at all. (I'm talking about invariant mass a.k.a. rest mass here, which is what physicists mean by "mass")

b) It interacts with the Higgs field.

Assuming the Higgs field is real (and the Standard Model is correct), it doesn't. The photon has no coupling to the Higgs field. If the Higgs field is not real (and the Standard Model which predicts it is incorrect), that still doesn't change the fact that photons appear to be massless.

The rest mass is zero.
a) It only has mass while in motion?

No, you're thinking of energy. A photon only has energy while in motion - then again, photons are physically required to always be in motion, so it's kind of meaningless to talk about what would happen to a photon if it stopped.

"Mass" a.k.a. "rest mass" a.k.a. "invariant mass" is a property of the type of particle, and it does not depend on what speed it's moving at (which is why it's called "invariant mass"). For particles that do not travel at the speed of light, it's the mass you would measure if the particle were at rest with respect to you. It turns out that you can calculate it from the formula
m^2 = p^\mu p_\mu = \biggl(\frac{E}{c^2}\biggr)^2 - \biggl(\frac{p}{c}\biggr)^2
whether the particle is moving relative to you or not (this can be experimentally verified for massive particles). For particles that do move at the speed of light (like photons), being at rest is not a well-defined concept, but if you use that formula to calculate m of a photon, you get zero.

b) Is there some kind of transformation associated with accel.. or decel - eration?

What sort of transformation would you mean?

Are not photons particles, assuming a mass, when, as per Heisenberg, they are measured?

As above, saying something is a particle does not imply a mass. In that sense we take it to mean some notion of locality, i.e. it's basically "concentrated" in one spot rather than being spread out like a wave.

 

[ZapperZ]

I am going to need some footnotes on this one!

"A photon is a particle that does not have a mass."
a) Does not the designation if it as a 'particle' imply it has a mass?
b) It interacts with the Higgs field. But, but, but the Higgs field/particle may or may not exist. Both are real possibilities - so where does that leave our little photon - still massless (or very small) and still zipping about at the speed of light. Yet if it is achieving the speed of light ... it cannot have a mass.

The rest mass is zero.
a) It only has mass while in motion?
b) Is there some kind of transformation associated with accel.. or decel - eration?

Are not photons particles, assuming a mass, when, as per Heisenberg, they are measured?

Help! Help! Help! I am trying hard not to make a pun about how I cannot see it.

There is a severe misunderstanding here on what is meant by the word "particle" as applied to photons especially. Would you still insist on the same criteria for photons if we instead call it "light corpuscular"? Would you also then want a light corpuscular to have mass?

So we instead call it a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical "particle", the latter of which has (i) a definite position (ii) a definite BOUNDARY in space of what it is (i.e. you can see where a ping pong ball ends), etc. This is not what a photon is. We didn't call it a "particle" because it has those properties. We call it a particle because its energy comes in quantized clumps. That's it!

And if you want to argue that "Hey, doesn't energy implies mass via E=mc^2?", then I'll point to you our FAQ that has dealt with this misunderstanding so many times already.

Moral of the story: never get hung up on the ordinary English words that we use to describe something in physics. The actual physics description of it is the overriding principle, and the words we use to describe it is a very weak attempt at understanding nature, and as can be seen here, is filled with unintended connotations.

Zz.

 

[luxiaolei]

Zz. You are great! I totally agree with you! Good thing about a foreigner learning physics is as you said, hardly trapped into these ''take for granted' understanding.

 

[cragar]

if light had mass then we could slow it down , but we cannot slow light down at all.

 

[BL4CKCR4Y0NS]

So BASICALLY ... the word "particle" used with "photon" is only a description and should not be taken literally?

 

[Born2bwire]

So BASICALLY ... the word "particle" used with "photon" is only a description and should not be taken literally?

Yeah. It's not entirely inconsistent though. It's just that when we talk about particles in the quantum mechanical sense we are ascribing the word particle with a different set of properties than the classical particle. However, most people rarely deal with or even hear about other true quantum particles. For example, I would expect that people would have similar confusion and questions about the nature of gravitons if the theory was as widely known as photons.

 

[croghan27]

I guess this makes my thoughts on the Casimir force off too. I had taken it that it was the momentum on the photons being communicated to the casimir plates - pushing them together ..

Oh well - back to the textbook

 

[Born2bwire]

I guess this makes my thoughts on the Casimir force off too. I had taken it that it was the momentum on the photons being communicated to the casimir plates - pushing them together ..

Oh well - back to the textbook

The Casimir force can be calculated by the momentum imparted by virtual photons, but these are not physical photons. They are mainly just mathematical tools but they generate accurate results.

 

[Dale]

So BASICALLY ... the word "particle" used with "photon" is only a description and should not be taken literally?

I would say that the same is true with ANY term in physics. They are all simply labels for some concept which is actually defined in mathematical and experimental terms. The common-usage connotations are not relevant to the physical definition.

Because of this nonsense words like "quark" are actually very good physics terms because they don't come with any contextual baggage that gets in the way.

 

[threadmark]

Sir Isaac Newton was the first to explain the mechanics of light, describing light as particles because his physics of particles being such a success was the first good explanation of light. Until he was corrected by the Dutch physicist Christiaan Huygens born in 1629 developed the idea that light moves like waves explaining the reflection and refraction just as well as the corpuscular theory.

 

[threadmark]

But ultimately it was expressed by Neils Bohr in the 1920 as the “theory of complementary”, which holds that the wave and particle of (in this case) light are not mutually exclusive to one another but complementary. Both concepts are necessary to provide a complete description.

ZapperZ your crude approach to labelling light to particles is offensive to anybody with a passion for history. You are incorrect to provide this explanation the way you have done. You said “So we instead call it a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical "particle",”. You do not take a respected physicists explanation and make it your own, the explanation of light is both wave and particle described by Neils Bohr not ZapperZ.

 

[ZapperZ]

But ultimately it was expressed by Neils Bohr in the 1920 as the “theory of complementary”, which holds that the wave and particle of (in this case) light are not mutually exclusive to one another but complementary. Both concepts are necessary to provide a complete description.

ZapperZ your crude approach to labelling light to particles is offensive to anybody with a passion for history. You are incorrect to provide this explanation the way you have done. You said “So we instead call it a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical "particle",”. You do not take a respected physicists explanation and make it your own, the explanation of light is both wave and particle described by Neils Bohr not ZapperZ.

And the game you are playing that is avoiding the PHYSICS is deceitful. If you look at QM's formulation, there's no such thing as "duality". We do not have to switch gears to describe something as a wave, and then go to a different gear to describe something as a particle. These are not the ordinary particle, nor are they the ordinary waves. One only needs to look at the formulation, not what ZapperZ or Neils Bohr says!

Respect these physicists, but don't worship them. Their words are not the gospel.!

Zz.

 

[threadmark]

You’re poorly mistaken, And your generalisation of QM increasingly offends me. I don’t worship physicists I do respect the input and understandings. Your attempt to Aristotle QM will live through the ages as a joke. Wasn’t it Niels Bohr and Rutherford that cemented Quantum theory with the model of the atom? and with this model nobody could doubt any longer the value of quantum theory as a description of the physical world of the very small. But one could go as far and say the world we see is a his interpretation and nothing is fact, But that would be ignorant wouldn’t it ZapperZ..for one to claim centuries of study and problem solving to mealy need respect is pitiful. I think it’s a way of putting your own spin on theories to claim intellectual points and to some degree feel like your contributing.

 

[ZapperZ]

You’re poorly mistaken, And your generalisation of QM increasingly offends me. I don’t worship physicists I do respect the input and understandings. Your attempt to Aristotle QM will live through the ages as a joke. Wasn’t it Niels Bohr and Rutherford that cemented Quantum theory with the model of the atom? and with this model nobody could doubt any longer the value of quantum theory as a description of the physical world of the very small. But one could go as far and say the world we see is a his interpretation and nothing is fact, But that would be ignorant wouldn’t it ZapperZ..for one to claim centuries of study and problem solving to mealy need respect is pitiful. I think it’s a way of putting your own spin on theories to claim intellectual points and to some degree feel like your contributing.

This is very puzzling. You seem to think that QM has not progressed beyond what Rutherford and Bohr formulated. It's as if things like Feynman's path integral doesn't exist and neither does QFT.

QM, as it is now, has no "duality". I don't need to change my perspective to describe the wave-like observation, nor the particle-like observation. If you're "offended" by this, then you are offended by QM, not by me. You are welcome to double check the textbooks and show me where what I've said is wrong. That's all I care about, not that you were "offended".

Zz.

 

[threadmark]

There you go again, how do you know what I’m thinking?. You think you know. But to better explain myself, you don’t dictate what QT or QM is, the principles of quantum theory stay the same”physical description of the very small“.

 

[ZapperZ]

There you go again, how do you know what I’m thinking?. You think you know. But to better explain myself, you don’t dictate what QT or QM is, the principles of quantum theory stay the same”physical description of the very small“.

Again, nothing in here shows any understanding of QM. "Very small"? How about an entity consisting of the 10^11 particles? Still small? And why is this even an issue?

Your objection from the very beginning is puzzling. If what you want is nothing more than an argument, then go at it. But there's nothing in what I've said that has been contradictory to QM. On the other hand, you seem to be more fascinated with the shadow of the animal than the animal itself.

If I don't dictate what QM or QT is, then you certainly are not the representative of Bohr or Rutherford. I'll stop representing QM and QT if you stop representing the history of physics.

Zz.

 

[threadmark]

What part in these series of posts did you interpret me trying to explain quantum theory. The original question was obviously asked by somebody who is trying to grasp an understanding of the speed of light not a big spill on quantum mechanics. Me giving history to this person will educate because it allows them to research the origans of the subject. Which when you go to school that’s how they teach, not that you would know.

 

[ZapperZ]

What part in these series of posts did you interpret me trying to explain quantum theory. The original question was obviously asked by somebody who is trying to grasp an understanding of the speed of light not a big spill on quantum mechanics. Me giving history to this person will educate because it allows them to research the origans of the subject. Which when you go to school that’s how they teach, not that you would know.

There's nothing in this discussion that is related to the original question. This is what you "objected" originally"

ZapperZ your crude approach to labelling light to particles is offensive to anybody with a passion for history. You are incorrect to provide this explanation the way you have done. You said “So we instead call it a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical "particle",”. You do not take a respected physicists explanation and make it your own, the explanation of light is both wave and particle described by Neils Bohr not ZapperZ.

So where in what I said THERE was it contradictory to the physics that we know of right now? This isn't a thread about history, the same way you tried to attack me in another thread because you didn't get the CONTEXT of the discussion? What was the error in that statement that you quoted?

EVERY concept in physics has an underlying mathematical formulation. That is the horse. What you are arguing appears to be based on the shadow of the horse. When I tell you that the horse have stripes, you felt "offended" because it wasn't in the shadow. Well tough! Learn QM! Or don't they teach you that in school?

Zz.

 

[Superstring]

if light had mass then we could slow it down , but we cannot slow light down at all.

yes we can. light slows down in any non-vacuum environment.

 

[cragar]

yes we can. light slows down in any non-vacuum environment.

no it doesn't , that is just the time lag of the photons hitting atoms, getting absorbed and then re-emitted , but they always travel at c .

 

[croghan27]

no it doesn't , that is just the time lag of the photons hitting atoms, getting absorbed and then re-emitted , but they always travel at c .

Good answer, cragar and like any good answer it bring up other questions ...

How long does it take the energy (it is the energy, is it not?) of the photon to be absorbed and then re-emitted? - is this the case or is the photon bounced off the mass of the atom??

Can I take it that the time is dependent upon the mass of the atom and the density of the 'atom cloud' (to invent a phrase). :shy:?

Does this influence astronomers looking at light from distant stars ... I know of the 'lensing effect' , that of nearby strong gravities, that of Einstein's (supported by the always delightful) Arthur Eddington - is there other interference?

Is there a similar sort of "Browning motion" from the interaction of the photons?

 

[Buckleymanor]

Good answer, cragar and like any good answer it bring up other questions ...

How long does it take the energy (it is the energy, is it not?) of the photon to be absorbed and then re-emitted? - is this the case or is the photon bounced off the mass of the atom??

Can I take it that the time is dependent upon the mass of the atom and the density of the 'atom cloud' (to invent a phrase). :shy:?

Does this influence astronomers looking at light from distant stars ... I know of the 'lensing effect' , that of nearby strong gravities, that of Einstein's (supported by the always delightful) Arthur Eddington - is there other interference?

Is there a similar sort of "Browning motion" from the interaction of the photons?

This link might cast some light on your enquiries.http://www.wired.com/science/discoveries/magazine/15-11/st_alphageek#

 

[Superstring]

no it doesn't , that is just the time lag of the photons hitting atoms, getting absorbed and then re-emitted , but they always travel at c .

i stand corrected.

 

[croghan27]

This link might cast some light on your enquiries.http://www.wired.com/science/discoveries/magazine/15-11/st_alphageek#

Hehehehehe ... it may cast light on my enquiries - even as it certainly makes murky the answers.

Is it the temperature that causes the 'delay' or the constituents of the BCE?

What is this BCE made of ... can I get some at the local Home Hardwear?

If temperature comes from the vibration of molecular/atomic sized particles and the closer to absolute zero you get is the closer to lack of vibrations, does this cause the 'light' or the energy of the photon, to delay its passage through the BCE?

I take it that: Her first trick was slowing a pulse of light to a crawl — 15 mph as it traveled through the BEC. was not referring to the photon itself (having been told they go at 'c' all the time) but of the admittance and rejection of the impulse provided by the photon through the BEC. But how does Pro. Hau 'freeze' a beam and then 'release' it?

Looks like the reporter was dazzled by reporting the story - as am I, in reading it.

(Is this a thread drift?)

 

[jtbell]

no it doesn't , that is just the time lag of the photons hitting atoms, getting absorbed and then re-emitted , but they always travel at c .

That simple "time lag between absorption and re-emission" picture is incorrect. I suggest you take a look at post #4 in the "Physics Forums FAQ" at the top of this very forum.

 

[cragar]

I see , interesting

 

[physics pfan]

There is a severe misunderstanding here on what is meant by the word "particle" as applied to photons especially. Would you still insist on the same criteria for photons if we instead call it "light corpuscular"? Would you also then want a light corpuscular to have mass?

So we instead call it a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical "particle", the latter of which has (i) a definite position (ii) a definite BOUNDARY in space of what it is (i.e. you can see where a ping pong ball ends), etc. This is not what a photon is. We didn't call it a "particle" because it has those properties. We call it a particle because its energy comes in quantized clumps. That's it!

And if you want to argue that "Hey, doesn't energy implies mass via E=mc^2?", then I'll point to you our FAQ that has dealt with this misunderstanding so many times already.

Moral of the story: never get hung up on the ordinary English words that we use to describe something in physics. The actual physics description of it is the overriding principle, and the words we use to describe it is a very weak attempt at understanding nature, and as can be seen here, is filled with unintended connotations.

Zz.

Dr. Z:

You have added a lot to this forum and I am in awe of your knowledge. But a couple of small points regarding your post.

First you say: "So we instead call it [the photon] a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical 'particle'..."

And then you say: "We call it a particle because its energy comes in quantized clumps. That's it!"

My guess is you wrote the latter statement in haste. We are really dealing here with the wave-particle duality of the photon which is a rather deep matter. If said photon of quantized energy terminated by spreading its energy and momentum over all available space paths then I don't think we would call it a particle; we would probably call it a "wave."
But of course the photon doesn't terminate over multiple locations; it terminates only at one space location. So we call it a "particle" because we have adopted the classical model that an entity of kinetic energy traversing space is a PROJECTILE that has a single space point of impact/termination. Whether this "projectile" model is valid for the photon is open to question [although not by most physicists], but that is another question.
But I would respectfully suggest that you reconsider the assertion that for the photon particle == quantized energy.

Physics Pfan

 

[ZapperZ]

Dr. Z:

You have added a lot to this forum and I am in awe of your knowledge. But a couple of small points regarding your post.

First you say: "So we instead call it [the photon] a "particle" because when we make some measurements of it, it tends to behave as if it is our ordinary, classical 'particle'..."

And then you say: "We call it a particle because its energy comes in quantized clumps. That's it!"

My guess is you wrote the latter statement in haste. We are really dealing here with the wave-particle duality of the photon which is a rather deep matter. If said photon of quantized energy terminated by spreading its energy and momentum over all available space paths then I don't think we would call it a particle; we would probably call it a "wave."
But of course the photon doesn't terminate over multiple locations; it terminates only at one space location. So we call it a "particle" because we have adopted the classical model that an entity of kinetic energy traversing space is a PROJECTILE that has a single space point of impact/termination. Whether this "projectile" model is valid for the photon is open to question [although not by most physicists], but that is another question.
But I would respectfully suggest that you reconsider the assertion that for the photon particle == quantized energy.

Physics Pfan

In a superconductor, the wavefunction for the Cooper pairs, which are paired electrons, are non-localized. This means that the cooper pairs, at any given instant before a measurement, are "spread out" all over the relevant space of the superconductor. Yet, these are "particles", meaning that these are composed of "electrons". It illustrates the case where even such "particles" CAN have the situation similar to what you deem as "classical wave", meaning they are spread out over all space the way a classical wave should.

It also means that photons can do the same thing even when we consider them as "clumps" of energy (and spin and momentum). So your assertion that only "wave" should be able to exhibit this spread in location doesn't hold true, because we have seen similar behavior in "particles" as well.

What people are missing here is that, once something can be described quantum mechanically, then hanging on to our classical biases no longer works! This is true be it for something we classically thought to be a wave (light), all the way to something we thought to be a classical particle (electrons, protons, neutrons, buckyballs, etc.). And the fact that these are consistently described via ONE single formulation (QM) and where all the wave-like and particle-like observations can be derived using just that one formulation, should dispel the myth that there is such a thing as a "wave-particle duality" in QM. There is a wave-particle duality in classical physics and in our minds, but there isn't any in QM! How can there be when you use the same set of description for everything?

Zz.

 

[threadmark]

If you are referring to the quadradic mean then yes that’s a formulation, but if your referring to quantum mechanics then no its not a formulation it’s a principle.

 

[ZapperZ]

If you are referring to the quadradic mean then yes that’s a formulation, but if your referring to quantum mechanics then no its not a formulation it’s a principle.

This makes zero sense.

Zz.

 

[threadmark]

The fact is, Niels Bohr gave us the description of the complimentary. being you need wave and particle functions to describe light. Look it up, its fact. you can also look up Luis de Broglie how stated
E=hv ; p=hv/c
On the left is the equation belonging to particles. And on the right are properties relating frequency/waves. even to measure the particle property of momentum you need to know the wave property called frequency

 

[Born2bwire]

The fact is, Niels Bohr gave us the description of the complimentary. being you need wave and particle functions to describe light. Look it up, its fact. you can also look up Luis de Broglie how stated
E=hv ; p=hv/c
On the left is the equation belonging to particles. And on the right are properties relating frequency/waves. even to measure the particle property of momentum you need to know the wave property called frequency

Except that Bohr and deBroglie ended up being wrong. Their ideas were the precursors to modern quantum mechanics. In particular, deBroglie's matterwave is a bit egregious because it only works with single particles in vacuum. If you were to place potential barriers, like a quantum well, then deBroglie's equation does not work.

ZapperZ cannot be more explicit in his statements here. Quantum mechanics has no wave-particle duality. It treats light, electrons, etc. all equally. The wave-particle duality is a consequence of trying to define quantum behavior within the limitations of classical physics. The behavior of quantum mechanics was observed prior to the development of a mature theory with such things as the photoelectric effect and the behavior of atoms.

 

[threadmark]

His 1924 doctoral thesis, Recherches sur la théorie des quanta (Research on Quantum Theory), introduced his theory of electron waves. This included the wave-particle duality theory of matter, based on the work of Albert Einstein and Max Planck on light. The thesis examiners, unsure of the material, passed his thesis to Einstein for evaluation who endorsed his wave-particle duality proposal wholeheartedly; de Broglie was awarded his doctorate.

 

[SpectraCat]

His 1924 doctoral thesis, Recherches sur la théorie des quanta (Research on Quantum Theory), introduced his theory of electron waves. This included the wave-particle duality theory of matter, based on the work of Albert Einstein and Max Planck on light. The thesis examiners, unsure of the material, passed his thesis to Einstein for evaluation who endorsed his wave-particle duality proposal wholeheartedly; de Broglie was awarded his doctorate.

Yep, that's a great story .. I tell it all the time to my students ... but what is your point? That was almost 90 years ago ... quantum theory has evolved just a little since then. You seem to have gotten huffy because ZZ and some others didn't give appropriate credit to the founders of QM when making statements. Please. This stuff is in the mainstream, and is part of the introductory chapters of thousands of textbooks .. it is public domain common knowledge, and THAT is the greatest testament to the founders of QM, that their theory has persisted and evolved for almost 100 years into "the most successful theory in physics".

 

[Born2bwire]

His 1924 doctoral thesis, Recherches sur la théorie des quanta (Research on Quantum Theory), introduced his theory of electron waves. This included the wave-particle duality theory of matter, based on the work of Albert Einstein and Max Planck on light. The thesis examiners, unsure of the material, passed his thesis to Einstein for evaluation who endorsed his wave-particle duality proposal wholeheartedly; de Broglie was awarded his doctorate.

And deBroglie did not develop a complete theory, again his ideas were direct precursors to modern quantum mechanics. Much of the foundations of quantum mechanics were worked out through the last half of the 1920's. Schroedinger developed the non-relativistic wave equation after deBroglie presented his electron waves. Heisenberg developed his formulation after deBoglie. In modern theory, deBroglie's ideas are a historical footnote. The next large development was quantum field theory and its application in quantum electrodynamics which was developed initially in the 1940's and resurfaced in the 1950's. All of these theories do not have an explicit wave-particle duality. In QM and QFT, we treat the photon, electron, gravitron, etc. all with the same physics. The phrase "wave-particle" is merely a stop-gap that attempts to bridge the properties assigned to classical waves and classical particles to how a field and its assciated particle behaves in quantum mechanics.

And really, if you are going to post word for word other people's work, you should cite where you took the passage from, in this case Wikipedia.

 

[DaveC426913]

And really, if you are going to post word for word other people's work, you should cite where you took the passage from, in this case Wikipedia.

Yeah. Threadmark: technically, that's plagiarism. Use the quotes feature.

 

[threadmark]

I think we need to stick to the facts,( Light can't travel at the speed of light?)
Well to answer this question, we need to ask what is light and what is it traveling in. empty space? , glass? Its 299,792,458m/s if E=mc^2. if light can't travel at the speed of light then tell us where Einstein got his formula wrong.

 

[ZapperZ]

I think we need to stick to the facts,( Light can't travel at the speed of light?)
Well to answer this question, we need to ask what is light and what is it traveling in. empty space? , glass? Its 299,792,458m/s if E=mc^2. if light can't travel at the speed of light then tell us where Einstein got his formula wrong.

It was croghan27 who made the faulty connection that all "particles" must have mass, and since light is a "particle", how can it travel at c! The rest of us have been trying to correct that by showing that a "particle", especially in the QM concept of light, need not have a mass! That's why a photon can travel at c!

Einstein did not get Special Relativity wrong. None of the responses that many of us have done here indicated that SR is wrong.

Now which part of that did you not understand?

Zz.

 

[threadmark]

Hey dude, I refer to the original question of this post. i study the history of physics, from Newtonian physics/classical physics and quanta. My books may be old but they still are relative today. It confused me when you stated it acts like a particle. So I post my books information to get feedback but you still say I am wrong. I came at you like I did because the information I have known for years had been protested by zapperz. I have taught this history to people.

 

[SpectraCat]

Hey dude, I refer to the original question of this post. i study the history of physics, from Newtonian physics/classical physics and quanta. My books may be old but they still are relative today. It confused me when you stated it acts like a particle. So I post my books information to get feedback but you still say I am wrong. I came at you like I did because the information I have known for years had been protested by zapperz. I have taught this history to people.

No one said the *history* was wrong ... they just pointed out that things have evolved a bit since the inception of QM, and people now know that the complementarity principle is basically superfluous, and was just a way of rationalizing the confusing results of QM to an audience that had only ever known CM. If you start out learning QM early, it still seems weird, but it's easier to come to grips with. It also means that we (scientists) are more willing to accept that the QM description of "particles" is complete without need for analogy to classical concepts of waves or particles.

 

[ZapperZ]

Hey dude, I refer to the original question of this post. i study the history of physics, from Newtonian physics/classical physics and quanta. My books may be old but they still are relative today. It confused me when you stated it acts like a particle. So I post my books information to get feedback but you still say I am wrong. I came at you like I did because the information I have known for years had been protested by zapperz. I have taught this history to people.

Too bad you don't understand the present!

If you continue to provide what are essentially a physics question, but with outdated historical answers, then you've provided erroneous answers. I'm shocked you didn't implicate any Caloric theory along the way to smack down Thermodynamics. You also seem to read things that aren't there. No one who responded to the OP even suggested that SR is wrong, yet you somehow implicated as such and merely added to the non-relevant discussion.

I strongly suggest you wait until a relevant historical question comes up, or hang around the History forum, before you jump in with your "expertise".

The OP no longer seems to respond or participate in this discussion, so unless he/she contact me for further clarification, I will assume that this has been sufficiently addressed. So this thread is done. This thread was never meant as a "historical discussion of outdated quantum physics".

Zz.