Technical Zone

I get lots of great questions from experts as well as novices.  The problem with expert questions is that they often take a lot of space to answer, and they make the discussions unreadable for the less knowledgeable.  Since my main purpose is to serve the public, not the physics community per se, I’ve decided to direct particularly technical questions that I can’t answer in a few words to this area.

143 responses to “Technical Zone

  1. Another question regarding the Higgs field. The Higgs field is all pervasive throughout the universe, but I assume we cannot detect our motion through it. Otherwise, it seems masses would change value slightly as the earth revolves around the sun. Is the reason for this because the Higgs is a scaler field and because the spin of the Higgs particle is 0?

  2. This question is in regard to the paper by Andrew Cohen and Shelden Glashow mentioned in your Oct 6 article titled “Is the OPERA Speedy Neutrino Experiment Self-Contradictory?.”

    In the comments, Lee Smolin said that “assumes that the relativity of inertial frames is broken, so there is a preferred frame.” If so, why are the results of the paper thought given the weight of a “refutation”? The assumption of a special frame of reference seems (to me) as extraordinary as what it claims to refute,

    As a layman, I thank you for this opportunity to ask this question which has been really bugging me!

    • The authors said “refute”, referring to a particular interpretation of the OPERA experiment. I myself wouldn’t have said “refute”, but that’s just a wording issue; the physics result is the interesting part. Their work makes clear that a very large class of modifications of Einstein’s theory would not be able to explain OPERA. I would say it makes OPERA’s result less plausible — but it is still just an argument. Until the OPERA experiment is shown to be wrong (either a mistake is found in OPERA’s technique, or multiple and/or better experiments contradict the result) the case remains open.

      • Sir, could the ‘indication’ of the higgs particle recently announced just in fact be confused with a di pole fermion – mimicking the higgs? Secondly, in the early stage of evolution ( ‘so called’ – linear expansion of the universe ) when no mass existed whatsoever ( inc Baryons ), does the case and argument for STR and GTR still hold true? As soon as mass appeared in this offspring ( recycled ) universe we now try to understand ‘everything’ centred around it’s existence – and the tiny parts of it. If the case for STR and GTR do not hold true in a massless space – then we are now somewhat confused? Suppose for one moment that Newton’s intuition is correct that the universe does form a background absolute and may be thought of as a separate entity – which just so happens to have mass occupying it + black energy etc. Let’s for argument sake remove all the mass from the universe by virtue of pure mathematics. What do you make of the universe then? Surely, it is still expanding with nothing in it! Moreover, let’s think of this huge void with a zero dimension where time is homogenous. ‘Zero dimensional space’ – papered by the german physicist late 19C Felix Hausdorff which has much relevance to consideration to fractals and shapes in nature. Could it be that the void of the universe is actually a pseudo space in the sense that it is not composed of Euclidian 3 spatial dimensions. If this could possibly be true and if the concept of time is homogenous – then all kinds of interesting notions are possible. Starting with Planks constant. LHC is in search of the Higgs because it causes other particles to bequeathed mass. However, If the universe void does have a zero dimension and is expanding at the rate of 300,000kms then once again we can change this value in Planks constant ( hypothetically ) in doing so the value of ‘C’ is immediately changed. In doing this we immediately alter the cohesive available frequencies in any of the standard model particles. The outcome of this revelation would be that all atoms would dissociate and be take to to a new low Zero Ground State – or alternatively a higher one depending upon the new hypothetical value given to ‘C’. Also, even more incredible would be the realisation that the ability of a photon to reach 300,000kms is not determined by itself. The ability to achieve this velocity is in fact determined by the orthogonal opening framework of the zero dimension of the universe. In the sense that for any object to move it must have a dimension to move into. The available mechanism providing this is Newton’s background absolute – which has been ignored since Michelson-morley/Eistein & Minkowski. It is creating ‘New Space’ second for second in every direction – not the thought of etheral wind! Thanks for your time in reading and considering this. From a book called Absolute Relativity Theory of everything.

  3. In 1966 — or perhaps a year earlier — one of my undergraduate students in the physics department of Queens College (CUNY) had entered a paper into the school’s science publication; “The Nucleus.” Its title was: “A NON-RELATIVISTIC MODEL OF DISTURBANCE PARTICLES.” None of our faculty had ever seen the term: “disturbance particle,” used before and the paper gave rise to a great deal of heated argument within the physics department, and even beyond it. It transpired that the student had ‘invented’ the term along with a model of something which he referred to as a “free energy field” capable of supporting disturbances which caused changes in local energy density. The student posited the existence of certain “Critical Numbers” which bore the units of energy density and which served as predictors of just how a locale of the energy field would behave as a function of its density. Above a certain critical number — his theory predicted — the locale would behave as a ‘particle.’
    One of the young student’s professors, Dr. Banesh Hoffman, pointed out that the proposed model was “attempting to resurrect the concept of an aether which we all know is impossible,” and that “his model does not transform relativistically.” When I replied that it was, after all, a “Non-Relativistic” model, Dr. Hoffman simply shrugged his shoulders, smiled, and asked: “What on earth does that mean?”

    It may be that, now, with the advent — possibly — of particles which travel faster than the speed of light, that young student’s model of “Disturbance Particles” may, in fact, mean something after all. Perhaps we should take another look at “The Nucleus” publication which bore that paper.


  4. Professor,
    this has been dwelling on my mind for quite sometime now. I am currently enrolled in college and there have been a few things on my mind that I have tried figuring out on my own as well as discussing with my peers. I have asked numerous science majors this as well and have gotten mixed responses. I have heard talks about whether teleportation is possibly these days and we both know it is not. Well, not with OUR current technology anyway. But if technology wasn’t an issue, it would most certainly be possible. I sincerely apologize for rambling on quite a bit in this letter to you, so I will quickly get to the point. I am sure that you are well aware that if a person were to be teleported from a certain point (lets say point A), their atomic structure would be broken down and then the data of that person (memories, personality, etc etc etc) would be transmitted to point B. I am well aware of quantum entanglement and whatnot. Also, the argument of the soul and religion cannot be used as part of this due to the numerous amounts of complications that they may cause. Now as for the new person that was constructed at point B, the atoms would be new ones, therefore making a new person. But, I decided to take this argument a step further. If the SAME atoms were transported from point A to point B, would it still be the same person? Or would it be a clone? Many people have said that it would be the same person, due to the building blocks being the same. However, there is something that still bothers me. When the bonds of the atoms are broken, the atoms go back to their original state. I.E. carbon, oxygen. And I would like your opinion on this, if the all of the same atoms were put exactly back into place as they were before the person was atomized, would it be the same person with the SAME consciousness, or a new person with identical personality, memories, etc etc etc with a NEW consciousness as well? I look forward to your response(s). Thank you for your time and consideration.

    • You have asked a classic philosophy/physics question, one that has been asked a million times before. Including by me, when I was your age. [Anyone who has watched Star Trek or its predecessors raises this question.] I am afraid that no one knows the answer, and it isn’t obvious the question can be answered in the next few decades or even centuries. Or perhaps ever.

      Consciousness is very poorly understood, in general. Moreover, it has two very different aspects. The *appearance* of consciousness is still not something well comprehended, but at least one can try to study it using investigations of the brain: one can ask how the brain allows us to make choices, for instance. That’s an active area of research in neuroscience. But worse — and this is crucial to the question you are asking — the *experience* of consciousness isn’t even obviously something accessible to scientific inquiry. Suppose you made a copy of a person and that person acted as though they were the same person as before, and claimed to have the same consciousness as before. How would you check that person’s claim? How would you know if that person was mistaken in his or her belief? What experiment could you do?

      Similar question (addressed, again, by many science fiction authors, and numerous philosophy classes); suppose all your neurons were encoded somehow in a computer, with all the connections and electrical activity repdrocued through software. This system would then act as though it were as conscious as you. But would it be conscious, or not?

      Let these questions dwell in your mind, because that’s where they belong. Perhaps you will someday have an insight into how to think about them. I certainly haven’t had one.

      • Lurk on this blog a great deal. Great job Dr. S. I am a physical chemist turned neuroscientist and hear these questions a great deal. I find that even otherwise objective folks (including scientists) can get bogged down in philosophical (and often, pseudo mystical) speculations about consciousness. Consciousness (which is really a perception) can be operationally defined (although there is always someone who will aver that the definition is not *real* consciousness) and examined objectively in the laboratory, both behaviorally and with neuroimaging. Questions about teleportation, computer cloning, etc. have two kinds of answers. The first is that Star Trek style teleportation and exact computer duplication of a brain are fantasy, not science. Consider the second scenario. What would it mean to “encode all your neurons in a computer”? Presumably this would mean constructing a model of the brain using some sophisticated combination of hardware and software. To what level of fidelity would we make our model? Not, clearly, at the level of elementary particles. Although the brain is collection of quarks and electrons, it seems that a model developed at this level might strain our current computing power. How about at the level of neurons? We could imagine creating a bunch of subroutines that model, say, an excitatory glutamatergic neuron’s hundreds of synapses, multiple neurotransmitter and neurohormonal receptors, it’s biochemical interaction with the surrounding astroglia and have the subroutines output a firing rate that models the release of glutamate from the neuron’s axons. We make similar models for each kind of neuron and glial cell in the brain, and put them together in a topographically organized fashion that maps to how one particular brain is put together. We’d have to model the brain’s continual remodeling that is necessary for memory and learning, model inputs from sensory regions that are greatly responsible for the brain’s architecture, model the feedback from possible motor movements, accurately model all the connections between neurons that have resulted from however many years of experience our potential computer clone might have had, and so on.

        Is there a layer of abstraction at which it makes sense to talk about uploading a person into a computer? I suspect not, because when I follow the logical path to what such a statement might actually entail, it appears to be practically, if not intrinsically, impossible. it is quite possible to construct toy models of brain function and they can tell us a lot about how the brain works. The question of whether a machine can develop consciousness is a different issue (it’s clearly true, our brains are machines and they are conscious, but this question usually refers to machines designed by humans). There is also the problem of the computer person’s body. Our brains live in the rest of our bodies and our brains’ experiences are predicated on how our extracerebral self gathers data. I suppose we could model a body, too, and how it reacts motorically to the external world. But you see my point.

        “But”, it is often said, “just suppose we *could* duplicate you exactly, either in a computer or in the flesh. Well, you’d have two people who were quite familiar with one anothers’ favorite drinks and intimate details of their past lives. They would certainly be more similar than identical twins, but they would be separate individuals, who would, over time, slowly diverge in terms of experience and behavior. As there is nothing magical (or supernatural) about what makes someone a person, those duplicates would have all the characteristic of birthed and grown people.

        A somewhat long post (and yet not long enough) that primarily argues that discussions of teleportation and personality uploading tend to ignore the real problems associated with actually performing the task and simultaneously somewhat mysticize the hypothetical result.

        Next time, I’ll ask how spontaneous symmetry breaking is like a phase transition (to which it is often compared).

    • When you say “consciousness” , it seems as if you meant to say the “soul” . As physical consciousness is the same as the persons working memory (it is the open interaction of various sections of your brain using stored chemical memory in your mind when the neurons begin transmitting all over you become conscious as a result of new experiences your consciousness changes and so do you and when you go to sleep or are knocked on the head like Tintin often it’s similar to miniature death as your brain loses complete consciousness . So as far as your question goes

      1) Yes the persons soul ought to be transported to point B [ that is if he can be kept alive] and he would be the same if the same atoms were used while a new soul /[he'd be a clone] if the original was terminated and a copy from the original data was created at pt. B.

      2)they would both have the same consciousness the fraction of a second after transportation but person before (proper transport or cloning) and person after (proper transport or cloning) would be as different from each other as you are from yourself a second ago[always changing]

      That’s why i’m sure it was federation rule to use the same stuff rather than other stuff (the Vulcans would never except the kill original then clone yourself method due to their Katra/soul etc. etc.) they had nothing against cloning just that they knew you can’t kill your self then give birth to a clone to live your life for you using your memories and everything.

      I hope this helps. :)

    • Sir, in a sense if you can imagine the universe providing the primary – dimension where time is 100% homogenous = ’0′ or 1., which is creating New Space second for second since the big bang. You may wish to think on the idea that since the beginnings everything that has happened has been recorded. Thinking on a bit more you may wish to consider that as New Space enjoys constant production at the rate of 300,000kms it may be thought of as an endless spool of magnetic tape ( cutting a plane of it ). Onto this tape the activity of every single atom – or particles -or photon which has ever existed is fully recorded second for second. For example in the time it takes you to read this short idea the local universe has/may have enlarged to a staggering 1 billion cubic miles. This number of course is determined by how fast you read – this number is probably not realistic. But in every second the universe is increasing its manifold size – but of course the sun remains at constant distance to us – and we are totally unaware of its local volumetric increase as it exists as a totally separate dimensional unity. This unity however may well provide the space into which Euclids 3 dimension may be located. Therefore maybe we just to enjoy 4 spatial dimensions and the Primary one is the expansion of the very universe providing new void which is necesary for anything to move in the remaining other 3? Food for thought. So it terms of teleportation if the entire universe consists of a homogenous time then wherever you wish to visit is actually where you are located! Think on the Horizon Problem – how can the temperature at the opposing periphery of the universe be uniform across a huge distance of 40 odd billion light years!! Surely there would exist a small variation in temp where the distance is so vast the possibility of information exchange impossible. ( ‘information’ exchange being the transit of temp from one side to the other to achieve this thermal equillibrium). Ridiculous it would take countless light years for such information to be transmitted across the diameter. Privately it must be because time is homogenous across the huge gap. Think of Newton speed=D/T. If time is zero or 1 then the transit time is identical to the actual distance = spontaneous. I think our basic understanding of the universe if full of flaws hence so many unknowns and paradoxes. In my mind temporal time which can only exist if matter is present all events occur in our experience with a background time reference of zero. Which in thinking more on this even the future. Before it has happened in temporal time. Kind regards ewj.

  5. Professor Strassler,

    It is accepted that the strong nuclear force decreases with distance, up to the size of the proton, then remain constant for longer distances. Is there any reason why gravity can’t be thought of the same way, with the strength decreases with distance up to the galactic bulge, then stay constant further out? Is there any research to that end?

    Thank you,

    • There certainly has been a lot of research as to whether there can be modifications of Newton’s law of gravity at long distance. Ever since the first galactic rotation curves appeared in the literature decades ago, there have been such efforts. Unfortunately, no modification of the force law seems to fit the data very well. For instance, different galaxies have very different shapes and sizes; what determines precisely where the force changes from Newton’s law to something else? The failure to find any modification of gravity that works well is just one of many reasons most physicists and astonomers are convinced that there is dark matter.

      • Could spacetime be rotating in some way, so that “further out,” the acceleration increases? Perhaps it might be rotating in an undiscovered dimension? [just a novice asking silly questions, hopefully in an appropriate place] Thanks

  6. Professor,
    When matter gets converted into energy and vice-versa. is the end result the “same” or something new? Seeing as how it has nothing to go back to, it seems like it turns into something new. Please give me your opinion.

  7. Hi Professor
    I am a lay person interested in physics. I was wondering if the first law of thermodynamics can really be considered a law. I was viewing a lecture from the Perimeter Institute website by Dr Natalia Toro. She stated that at the sub-atomic level you can borrow energy to make particles as long as they decay right away and the debt is paid really fast. Shouldn’t a law hold in all circumstances? I have also read that our sun does not have the energy required to burn. If not for the uncertainty principle allowing protons that according to the math do not have sufficient energy to get close enough to fuse to actually get close enough? Are these events somehow related?

    • There are indeed different kinds of laws in physics. There are laws that say: this NEVER happens. There are others that say: the probability that this will happen is so tiny that you’ll NEVER see it happen in the entire history and expanse of the universe. Thermodynamic laws are of the second category, and they do break down as the number of particles in the system you are studying becomes sufficiently small.

      • Thank you for your reply. The Classic Laws of the Macro world just do not hold in the Quantum micro realm.

        • Wait!! What you say is true, but it’s not quite the right conclusion in this case.

          Statistical/thermodynamic laws are not laws of classical physics which fail at the quantum level; that’s something else.

          Statistical laws are laws that govern large numbers of similar objects; they fail when the number is small. This is true EVEN if the objects are macroscopic and effectively classical.

          For example, one version of the law of increasing entropy: it tells you that if you take a barrel full of marbles, with all the white ones at the top and the black ones at the bottom, they will mix, but they will never unmix [i.e. the probability is so low that it will never happen if you shake the barrel for the rest of our life]. But it is not true [or more precisely, it requires some modification] if you take a little vial with only six marbles in it. Unmixing will accidentally occur in that case, now and then. That’s all classical (i.e. non-quantum) physics.

      • “There are laws that say: this NEVER happens…Thermodynamic laws are of the second category…”

        Thanks for that, it helps my brain tremendously!

  8. Since you mentioned entropy. In a lecture by Fay Dowker, she said that Jacob Bekenstein said that the entropy of a black hole must be proportional to the surface area of the event horizon. Steven Hawking later found that Black Hole Entropy = Event Horizon Area(in Planck lengths)/4. It got me to thinking that this equation should also hold for any system. Therefore the total entropy of the universe = 4π(radius of the observable universe in Planck units)^2 /4 or π r^2. It also follows that the cosmological constant is really the rate of increase in Universal entropy? Am I way off base here or does this make sense to you?

  9. Michael O'Brien

    Regarding accellerated cosmic expansion, could one correctly imagine all the stuff of the primordial universe as being scattered by a central explosion, giving more boost to the more centrally located matter, and having less oomph near the perimeter, thus having the the parts with the most impetus travelling faster (hence farther away now) than the less proximal primordial material at the time of the bang?
    Also, (if the above idea is out), could the eons old radiation pressure (and other pressures) from all the outgassing of stars, supernovae, QSO’s etc, cause a repulsion in the whole system, of one part for another, resulting in dispersion being greater in the distance than nearby?

    • In the theory of the Big Bang, there’s no center, and the Big Bang is an expansion of space itself, not an explosion of stuff into space. The image that you have is giving you the wrong impression of what is actually believed to have happened. (Unfortunately this misunderstanding of the Big Bang is not only widespread, it is actually reinforced by most public TV programs on the universe, which show a completely erroneous picture of an explosion. I was appalled to see this even on Steven Hawking’s latest TV series.)

      If there *were* a central explosion from some central point, then we would not expect the part of the universe we can see to look almost the same in all directions, and to be largely uniform.

      As for radiation pressure from all those photons out there — first, the the effect is far too small even on ordinary matter. And most of the matter of the universe is “dark matter”, a type of particle that neither emits nor absorbs photons, and wouldn’t be affected by radiation pressure anyway. Finally, because the universe is almost perfectly homogeneous (at least the part that we can see), without a center, there is equal pressure from all sides, and no net force outwards. Those photons do affect gas and dust inside of galaxies, and around stars, so these effects are studied by astrophysicists and astronomers in detail.

  10. Michael O"Brien

    Some early renderings of the CMB sky show a disk with a red half, swirling into a blue half. The explanation was that this was before certain corrections were applied. Doesn’t this indicate an off-centered-ness to the energy that was recorded, suggesting motion in some direction?

    • Yes — the universe is engaged in an overall expansion, and is largely uniform on average, but any individual galaxy is moving relative to that overall expanding uniformity, and ours is no exception. This creates a Doppler effect in the cosmic microwave background (CMB), which is uniform with respect to the overall expanding universe. The existence of this effect was no surprise and was fully expected.

      Once you remove that one effect, you can see that the universe at large scales was extraordinarily uniform in the distant past, at the time when the cosmic microwave background became uncorrelated with what the matter around it was doing.

      You can think of that as a little like the motion of a boat through a uniform sea. To realize that the sea is uniform, you have to first correct for the motion of the boat through the water.

      • I wonder how inflation affects this issue – since the universe leaves the inflationary era at different points at different times, does that not provide some kind of centre to our universe?

        • Well, the fact that inflation may make the shape of the universe very complicated may indeed mean that there are edges between different “patches” where the universe is very different from what it is in the middle of a region. But unless you are in a rather small inflationary patch, or near an edge of a patch, there won’t be any simple experiment you can do to figure out where the center of your patch is. In principle you could try to define it but in practise you won’t be able easily to detect it.

  11. At large scales, it’s safe to ignore quantum mechanics and focus only on general relativity; at small scales, you can ignore gravity and concentrate only on the quantum aspect of nature. So it seems you never need both quantum mechanics and general relativity at the same time in order to descrive a physical phenomenon.
    Knowing this, do we currently have some need for a theory of quantum gravity? Obviously, understanding the fundamental rules of the universe is a noble goal by itself, but what I mean is if there’s a known and observed phenomenon/physical object that is currently waiting quantum gravity to be properly understood. I’m guessing some sort of weird star or black hole?

    • In a sense, if we had an immediate need, we’d also have an experimental setting in which to study it. So the answer as to whether the need is clear is perhaps no.

      On the other hand, it’s good to study it in case we run into it in an unexpected place. If extra dimensional effects were detectable at the LHC (so far indications are that they are not) then we might in fact run into gravity (in the form of quantum black holes and gravitons etc.) at accessible energies.

      Also, the relationship between quantum field theory and string theory that was discovered by Maldacena and friends makes us want to understand quantum gravity as a way to understand quantum field theory better — and quantum field theory really is part of the real world. We are more likely at the LHC to run into a quantum field theory process that can be usefully understood using gravity (classical or quantum) than to actually run into quantum gravity directly.

      But when Einstein developed general relativity it wasn’t clear there was a need either. Only after the theory was developed did it occur to people to look at the bending of light by the sun — a new type of experimental question. Today we use this “gravitational lensing” to study the universe.

      So you can see the argument that you should develop the theory in hopes that an experimental test will become clear once you understand it. And at that point this might lead you in new experimental or observational directions where you really would have a need for quantum gravity on a regular basis.

      • And, of course, as any good newspaper would say, quantum gravity may help us understand why there’s more matter than antimatter in the universe (haha, just kidding).

        Anyway, thanks for the answer!

  12. Update on the mass of neutrinos:

    The article claimed that the experiment narrows down the mass of the neutrino “to less than 140- to 380- thousandths of an electronvolt”.

  13. Dr. Organtini has a paper explaining the Higgs mechanism:

    Between equation 9 and 10, there is a new term, (phi^4), is that because we are assuming that the self-interaction of the Higgs field is negative?


    • The approach he takes is interesting. The one I am preparing is very different; they will be complementary.

      I think he just adds this term because he can… but I should read this carefully to see if he has a more motivated line of argument.

  14. Hi Matt,

    I have a simple question (these are the most difficult to answer sometimes). Maybe the answer has already been given.

    It s about the Zero Point Energy of the EM field.
    As a consequence of the Heisenberg Uncertainty Relation (or non-commutativity of operators), there remains some energy once you have removed all the photons (one half h omega). This is the ZPE. You can show that you still have an electric field and a magnetic field. Their mean value is zero, but there is a non-zero variance (thus some energy). So you have E and H, but NO photons. First question : can E and H be considered as noise ? I guess yes (zero mean value and non-zero variance). That’s probably what people refer to when they say “fluctuations”. Does fluctuation mean noise ? Is it equivalent ?

    Second question : this happens with NO photons around. My understanding is that ZPE is a stationary field, not propagating. There are really NO photons whatsoever. Neither real nor virtual. Right or wrong ?
    Usually people think about these fluctuations as virtual photons popping in and out. But this means there are photons (even if only virtual). Isn’t that contradictory with the fact that the number of photons is zero ?

    Thank you.


  15. if we happen to remove our hand just when flow of electrons is approaching the other end of wire what will happen to the energy spent by the electrons and where will it go?

  16. the flow of electrons constitutes current, now we know that the speed of the electrons can be considered as about 90-97% of light and if suppose a wire is plugged in the socket of 220V and because of the difference in potential as on end of the wire is free, and naturally the flow of electrons will be there. initially i placed a conductor at the other end of the wire and as soon as the potential was developed, the flow of electrons was there, i suddenly remove the conductor as fast as the flow of electrons by some means( although not possible) what will happen to the energy spent by the electrons as conservation of energy is true?

    • I am afraid that right from the beginning you are profoundly confused about how current works and what electrons are doing inside a wire both in the absence of and in the presence of current. Your statement about the speed of the electrons is both incorrect and confused. First, you have the speed wrong. But second, and more important, it isn’t the speed of the electrons that determines how quickly the current builds up. That’s determined by the speed with which the electric field builds up along the wire. Moreover, just like atoms in a light breeze, the electrons’ motion is mostly random with a slow overall drift, so their speed isn’t what determines how fast they flow in the wire. The electrons move fast, but most of that motion goes nowhere; the slow drift that leads to a current is very slow. And energy conservation inside a wire is extremely complicated, because the electrons are regularly banging into things inside the wire and losing energy to the lattice of atoms that make up the wire; that’s why the wire heats up (through electrical “resistance”) when you pass a current through it, and why the current doesn’t keep growing even though an electric field should be accelerating the electrons to higher and higher speeds. You can’t keep track of the energy of the electrons unless you keep track of all the heat that’s being lost to the lattice of atoms.

      In superconductors things are different, because there is no resistance; but you don’t use those in ordinary wires.

  17. I have a fundamental question:
    When I think of elementary particles as the electrons and quarks, may I think (imagine) of them as “euclidean points” in space, as something without structure, or, as I understand from quantum field theory, as ripples in their corresponding fields, i.e. as something with 3 dimensions (the dimensions of the field)? Maybe as an infinitely peaked ripple in the field (~deltas)? If this is the case, is it correct to imagine an electron “flat” field that becomes extremely peaked when an electron appears?

  18. I hv posted the following under “New ? Start here”.
    I later noted there are ‘Enlightend’ souls here (Technical Zone) who may shine my path too.
    Pls comment if you find my question worth your attention.
    I am looking for an answer in terms of Particle Physics, if possible.

    UT | November 23, 2012 at 3:00 PM | Reply

    Respected Prof,
    It is indeed privilege to post a question to you directly. If fortunate enough, (me) expect to receive a considered reply.

    Of late a simple question is bothering me a lot !!
    Given :
    When two bodies (A & B) collide Kinetic Energy is exchanged. Total Momentum is conserved.

    Question ?
    1) How does the bodies retain the Kinetic Energy.
    ( we do know how the Heat is retained)
    Observation: :
    More Kinetic Energy (equals more velocity). Say A was faster before pushing B (from behind, like cars in the same lane)

    After collision, change in velocities of both bodies takes place. ‘A’ slows down & B goes on faster after a push.

    The change that has enabled the body B to negotiate the space in front more efficiently (faster).

    Question ?
    What has changed ?
    Is this change something to do with the space property ?
    Is this change has to do with the body and space both ?
    or this change has changed something inside A & B.

    Interesting Scenario !!

    Say we fire a bullet. The bullet has two motions.
    a) forward (x axis)
    b) spiraling around its forward motion (x – axis)

    c) the bullet strikes a thin wire. It acquires another motion. Spinning (in addition to above (y-z-axis) as well.

    To make it simple – the question is ?
    How does the body retains the ‘Memory’ of motion (on all 3-axes).
    the question is :
    How does this memory is transferred to new body on collision ( in what form, from where to where (mass to mass, of course)
    From where it is released.Where it is received. And where it is then retained ?

  19. Dear Matt, thanks for a great website!

    I was reading an article on the “5 sigma rule” of experimental physics and although the article was not very deep, it got me thinking and I have a few questions regarding inference drawn from physics experiments:

    How do scientists calculate the uncertainty in the results concerning a scientific theory? I.e. how do we know “how many sigmas we are at”?

    I would guess that most (all?) scientific data would be far from normally distributed, so do the scientists invoke the central limit theorem? If yes, I see a couple of potential problems:

    (1) We naturally only have a finite sample, hence the normal distribution assumption is only approximately correct. What happens if the convergence to the normal distribution happens extremely slowly for some reason? Is there a way to test for this in a given scientific experiment (without imposing additional assumptions on the data generating process)?

    (2) In a similar vein, and taking the Higgs as an example, I imagine that both ATLAS and CMS collect huge amounts of data, thus strengthening our belief in the CLT-approximation. But if the Higgs in only rarely detected, we actually have significantly less data than one would imagine from the number of collisions being recorded. Is stuff like this taken into account when calculating the “5 sigma”? (I would guess yes, but I dont know the procedure)

    (3) What if the assumptions underlying the particular central limit theorem being used are violated? How do we check for this? And can we be certain in any conclusion regarding the validity of the assumptions?

    Are the above questions trivial for a physicist or could they pose problems? Are scientists actually asking these questions when doing experiments and inferring from them?

  20. kashyap Vasavada

    Hi! I am a retired physics prof. here. Only a few days back I became aware of your excellent blog .From now on I will read your blog carefully!
    I have two questions. (1) I understand that baryon masses cannot come from Higgs. But I have a feeling that quark model will not work with zero or very small mass quarks anyway. Will the lattice gauge calculation work with zero or very small quark masses? So Higgs may be necessary for baryons also. What do you think?
    Also can you give me a reference which calculates with what energy quarks or gluons collide for a given cm energy of the two protons. I suspect it is quite involved and depends on the specific details of each collision in addition to the cm energy. Perhaps for each event one has to reconstruct. Is this right? Thanks.
    Kashyap Vasavada

  21. kashyap vasavada

    I am withdrawing the first question!!! I got the answer in Wilczek’s article on origin of mass. I will appreciate it if you answer the second question.

  22. In the case of teleportation I have no idea if the person would be the same person, but as for if the same atoms would equal the same person, there have been cases where half a persons brain has been removed because of seizures or other brain malfunctions, yet they have remained the same person, functioning quite well in fact. and finally I keep hearing of this thing called space. What is space and how can it expand if it is not expanding into anything, and finally can any material thing, such as the universe, be infinite?

  23. I’m relatively confused, aren’t we all at times?

  24. Tony (Rácz) Rotz

    What are your thoughts on Tesla?

  25. Tony (Rázc) Rotz

    If you strip away all the particles, waves, etc. what remains must be some sort of framework, right?

  26. Tony (Rázc) Rotz

    Or is space upon which the universe constructed simply the void, absolute nothingness.

  27. Tony (Rácz) Rotz

    Too many questions without answer.

  28. I think we may be suffering from a confusion of terms.
    Sir Hubble discovered that the Universe is expanding. We now say that Space is expanding.
    If we agree that the Universe occupies space, then we ought to agree that there’s lots of as-yet-unoccupied space for it to keep expanding into.
    We’ve learned from the behaviour of mass that we can see, that there’s mass out there that we can’t see. We call it Dark Matter.
    We’ve learned that the expansion is accellerating, and we call the impetus Dark Energy.

    Now as to it’s expansion, we’ve learned that it is also an accellerated expansion

    • Interesting points Mike but I don’t think anyone knows. Much like a different direction and dimension. 300 years before the birth of the Son of God? A man stated that we live in 3 dimensions. Maybe such thinking was appropriate for his time to make sense of everything. But how do we not know that we may only live in 1 so called dimension ( universal 1D field ) comprising of the entire universe? ( He ), and we now think we exist in 3D because we have the ability to move in orthogonal directions ‘In this Space’ that has been produced by it? A different dimension or just a change of angular direction in the same 1?

      I do not speak as a professional but that seems obvious but a potentially dangerous notion to follow. We hear of multiple dimensions now which come with more speculations than I could ever dream up. Make a statement then put some maths on the table which nobody can refute then the speculation must be correct? Or is it?

      A swallow can navigate 1000’s of miles in cloud with in absence of any previsited waypoint sightings – does it just fly around in larger circles until it finds its destination? Some things we may never know. In a 1D speculative vision maybe it is receiving information from it’s destination and simply follows this beacon.

      I don’t think we can depend on all our current definitions. For example Newton and Einstein had great ideas about gravity and put that into equations – but nobody knows what causes it – it is a mystery.

      • @Edward Johnson.
        ”Interesting points Mike but I don’t think anyone knows.”
        I don’t believe I had asked any questions up to that point. I had only made a few points, and then net trouble forced me to post half my idea early, and fix the rest in the next part. Unfortunately, more computer problems kept me distracted and made me keep it short, and I settled for a complete sentence and hit send.

      • @Edward Johnson:
        . . . Furthermore, the rest of your reply immediately departed from the topic of cosmology and never returned, so it doesn’t warrant a response.

  29. . . . which, as I’ve said, we call Dark Energy.
    I can understand that we can tell the ratio of visible matter to invisible matter through techniques involving gravitational lensing, and come up with percentages like, ”Dark matter accounts for 23.3 percent of the cosmos, and dark energy fills in 72.1 percent.” ., but for the second number, aren’t we comparing apples to oranges, i.e. matter to energy?

    • “More recent research has found a neural connection between the eye and “Cluster N”, the part of the forebrain that is active during migrational orientation, suggesting that birds may actually be able to see the magnetic field of the earth. [45] [46]”

    • Then if migrating birds can see gravity or magnetosphere then I suppose it must be in some form of light or radiation? Being related to dinosaurs and around for a lot longer than us maybe they have evolved this ability? And see different colours of it in the Cosmos?

  30. . . . uh, I found this:
    ”The source of this dark energy and the reason its magnitude matches the inferred magnitude of the energy in empty space currently is not understood, making it one of the leading outstanding problems in particle physics today.”

    taken from:

  31. Would you please write an article on inflation (when the universe expanded at faster than light). I am particularly interested in how long inflation lasted, the time after the big bang it began, and how large the universe was before and after inflation. I realize different theories may have different answers. I have read that some theories say the universe after inflation was the size of a basketball. However the popular press always gives the impression that after inflation the universe was millions of light years across.

  32. Here’s When it happened, according to Wiki:

    ”In physical cosmology, cosmic inflation, cosmological inflation, or just inflation is the extremely rapid exponential expansion of the early universe by a factor of at least 1078 in volume, driven by a negative-pressure vacuum energy density.[1] The inflationary epoch comprises the first part of the electroweak epoch following the grand unification epoch. It lasted from 10−36 seconds after the Big Bang to sometime between 10−33 and 10−32 seconds. Following the inflationary period, the universe continued to expand, but at a slower rate.

  33. I see exponents didn’t come out well.
    1078 should be 10^78,
    10-36 = 10^-36

  34. I have read the wiki article. I guess expansion by a factor of 1078 tells you something but you would need to know the size beforehand and the formula for using this expansion factor to compute the size afterwards. What I’m looking for is along the lines of “before expansion the universe was the size of a proton, after exponential inflation it was the size of a soccer ball”. Because no one ever says it like this then the popular press says things like “after expansion the universe was the size of galaxies”.

    • kashyap vasavada

      Good question. I see that Matt has not gotten around to write about inflation. The way I understand is that different inflationary models give different sizes. Most likely the patch which gave rise to our universe was of the size of an atom or even a nucleus. This gave rise to models of multiuniverse coming from other neighboring patches.Factor of 10^78 is just one of the models.Some say it could be as high as 10^10^10!!! The newspaper story about galaxy size after inflation are flatly wrong. After inflation, nucleons, nuclei and atoms had to be formed
      before galaxies were formed by gravitation. But of course there are lots of speculations.

  35. Hi Prof Strassler, I really appreciate your site very much. It is the first time I find an understandable explanation of the standard model and of the Higgs mechanism that does not require much technical skill.

    I have a quite particular question. I though to post this question in this section because of it peculiarity, hope it is the correct place.

    The question is about the spin-orbit interaction of the electron within an atom. I read that about a century ago, when the Bohr model of the atom was used, the forecasted value of the spin-orbit interaction was different by a factor 1/2 from the measured value. This fact was explained by a particular relativistic effect, the Thomas Precession (I think that this should be expressed by the fact that the so called g-factor is 2 and not 1 as forecasted in the Bohr model). Then, when the Bohr atom was no longer the reference model for the atom, the value of the g-factor was explained as a result of the Dirac equation.

    In several physics sites the value 2 of the g-factor is explained as a relativistic effect, but not always. I found an article on arxiv ( where the author explains that:

    1) The considerations made about the g-factor in the context of the Bohr atom when the Thomas precession was discovered were not correct, and relativity was not necessary to explain it (page 13 of the article).

    2) The g-factor resulting form the Dirac equation is just a result of the non-commuting properties of the momentum operator, and has nothing to do with relativity.

    So, should I conclude that there is a common misconception about the origin of this phenomenon and that really relativity has nothing to do with it ? Or may be there is some mistake in the article I wasn’t able to find ?

    If the article is correct on this point, it is also correct to say that the Thomas Precession is a phenomenon that is forecasted by relativity but actually never verified experimentally ?

    Thank you very much for your attention and for your time.


  36. Matt: I have been trying to understand the magnetic properties of protons and neutrons. I have a problem with the sign of their magnetic moments. The proton has a magnetic moment of +2.79 nm. If a proton includes one up quark with its spin vector pointing up, and one up quark with its spin vector pointing down, wouldn’t the magnetic moments of the two cancel? And if they cancel, wouldn’t the net magnetic moment of a proton be solely from its single down quark, and therefore have a negative value?
    The neutron has a magnetic moment of −1.91 nm. If the two down quarks have opposite spin, shouldn’t the net magnetic moment be from its lone up quark, and therefore positive?
    I would greatly appreciate any clarification you could provide. Thank You, Rod

  37. Matt: I am a postdoc in Argonne and i will be attending your Colloquium on the 15th. Perhaps we can talk for a few minutes then? thank you

  38. Philip strassler

    Matt i have a theory: if someone where to drill a hole through the center of the earth and jump in the person or object would be sent into a endless loop.

  39. Matt, I have a question. What came first the Big Bang or Inflation? I’ve heard differing opinions and wonder what is your ideas on it are?

    • It’s partly a matter of definition, which is probably why you’ve heard conflicting remarks.

      Inflation occurs and expands the universe enormously, but during that period the universe is COLD AND EMPTY.

      Then inflation stops, and the energy that was driving the inflation gets dumped into particles. At this point the universe becomes HOT AND DENSE. The universe still expands, but much more slowly.

      Now: Do you define the Big Bang to be the second period, or do you define it to include the first period and anything before it? Depending on your definition, you would say “The Big Bang comes after inflation” or “The Big Bang comes before inflation.”

      I think it makes more sense to define it as the hot, dense period after inflation, but it really doesn’t matter, as long as you understand the sequence of physical events.

  40. About the bird magnetic compass navigation thing:

    Researchers at Virginia Tech in 2006 devised an experiment with pigeons which conclusively showed that the birds were able to navigate over long distances best and tastest if they were allowed to view sky polarization (a clear sky) at dusk and at dawn.

    It is not impossible that birds use special neurons sensitive to magnetic fields to navigate, but since most birds have natural tetra chromatic vision, their ability to use Haidinger’s brush for navigation is a more likely explanation. To show that they were navigating using only magnetic fields, the birds would need to be released with blinders or with their vision impaired. Not a kind thing to do, but that’s probably the only way to settle the issue one way or the other.

    I can’t understand why the magnetic field sensitive neuron issue keeps coming up here. Perhaps we need the Amazing Randi to make the call, because I don’t think the ones who favor the idea of a bird having an internal compass are being honest.

    • If an electron has 9.1 x ^10-31 Kg mass and velocity according to Rutherford atom model.

      Then the electron is constantly curving around a nucleus experiencing radial inertia x Mass ( particle or wave )

      The electron is held captive by the nucleus

      Whey then cannot the electrons themselves be responsible for the production of gravity?

      Then the more matter you have in an object hence the increase in gravity experienced externally?

      Is this a crazy notion?

      • It’s not that it’s crazy; it’s simply inconsistent with experiment. Gravity bends light rays, even though photons have no electrons. Moreover, if what you say were true, then different isotopes of the same atom (which have different masses but the same number of electrons) would have different gravitational pulls, violating experimental tests of the equivalence of inertial and gravitational mass.

        • Thanks for your reply comment. So are atoms the source of gravity whether a standard atom or it’s isotope form?

          • The point is: the gravitational pull of two different isotopes of carbon 12 and carbon 14 is different, even though they both have the same number of electrons. Only the number of neutrons is different.

          • Thanks for the example. However i guess both 12 and 14 where at exactly the state when measurements taken?

          • Of course. Here’s the most recent, and most precise, experiment, actually done with rubidium but the point is the same. Note they find that gravity pulls at a rate proportional to mass (not to the number of electrons) to a very high precision: they “find that the Earth’s acceleration for both isotopes is the same to within an accuracy of two parts in ten millions. “

          • I guess we can therefore discount PE as it is dependant upon a G being present in the first place – or an artists impression of what space curvature should look like should it have a G present to create one

          • I don’t understand this comment — sorry.

          • To rephrase :

            Does G pull more on energetic atoms/isotopes then?

          • As far as we can tell, gravity doesn’t care. Gravity pulls on energy, wherever it comes from… from the energy stored in mass, from kinetic energy, from potential energy. Gravity doesn’t look to see if that energy comes from atoms or photons or neutrinos or one isotope versus another. This principle, that gravity is *universal*, in that it pulls on energy no matter what that energy’s source, is fundamental to Einstein’s theory of gravity. If it were not the case, you could not view gravity as the curvature of space and time — which, similarly, doesn’t care what type of object makes it curve, or what type of object it is forcing into an apparently curved path.

        • And what experiment here on Earth demonstrates that gravity bends light? Maybe the gravitational lensing affect observed is due to some other phenomena especially as a photon as you say has no electrons and is massless. Surely it must be some other physical characteristic which enables gravity to have any influence upon it?

          • Gravity pulls on energy and momentum, not on mass. [That's why energy and momentum appear in Einstein's gravitational equations, not mass, in contrast to Newton's equations.] Photons certainly have energy, and that’s why gravity pulls on them.

        • But a photon has a mass associated with it’s velocity does it not? And the lensing caused by general relativity affect of the so called curvature of space & time? So what experiment shows that we can curve space according to GR?

          • Edward, you really do ask some thought-provoking questions. Looking for better demonstrations of GR gravity predictions and effects, I had no idea there was an issue with the interpretation of a recent solar eclipse event:


            This relates to our understanding of gravity even on a large scale. Using a LaCoste-Romberg gravimeter that was set up to capture gravitational variations on the surface of the Earth, the ‘anomalies’ the researchers observed were two negative gravity peaks which began trending an hour before and an hour after total eclipse, which geophysicists claim is impossible to explain in terms of tidal effects either solid or liquid.

            A great deal has been written about this particular anomaly recently. There are those who believe it should cause us to rethink a number of things we thought we understood about time and gravity (see also ‘Demise of Gravity, Birth of time’).

            Geophysicists are still grappling with new info about the Earth’s core these days. It probably has tides too, besides which, it super rotates in an Eastward direction.

            Rutherford’s version of the atomic nucleus, gleaned from bombarding it with helium nuclei (alpha particles), suffers from the idea that if electrons in an atom are accelerating even when not changing quantum state, it would mean that they would need to lose energy until the electrons collided and fused with the nucleus. Of course, electron degeneracy actually occurs in neutron stars that are formed when a supernova remnant within 1.4 and 2.3 solar masses collapses into a cubic chunk of neutronium (OK, the structure is more complex than that, but you get the idea).

            Acceleration means something entirely different on a quantum scale, but suffice it to say that the Rutherford model is too deficient in many respects to refer to in a modern discussion.

          • Guys — you’re having an extensive 1 on 1 discussion. Could you please take this to your own email accounts, and not do it publicly? Thanks!

          • A very interesting find Daniel – thanks.

            So what happened with their 2002 work? Was there any follow up with the more sensitive instruments proposed?

            I wonder what was happening around the world at the time ref earthquakes.

            And what is their definition of a stable power supply used Maybe the near eclipse caused a dip in power production. Or maybe the ground became locally depressed by a miniscule degree?

            Fascinating thanks


            Following your earlier attached a thought invoking presentation above

          • This is a matter of definition, as I said.

            Particle physicists would say: Gravity pulls on energy and momentum, not on mass. [That's why energy and momentum appear in Einstein's gravitational equations, not mass, in contrast to Newton's equations.] Photons certainly have energy, and that’s why gravity pulls on them.

            If you try to define relativistic mass in general relativity, you find it is extremely tricky to do. Rest mass, which particle physicists call “mass”, is no problem.

            In short: particle physicists would say: “photons are massless, period; gravity pulls on energy and momentum, as manifested in the curvature of space and time; anything with energy, including photons, will travel on curved paths in the presence of curvature; and that’s exactly what the equations say.”

            Of course, if you want to define mass differently, that’s up to you — you can call a rose by any other name, or redefine a carnation to be a rose. You’d just better be sure *which* definition is being used. The equations, and their predictions, remain the same.

    • If an electron has 9.1 x ^10-31 Kg mass and velocity according to Rutherford atom model.

      Then the electron is constantly curving around a nucleus experiencing radial inertia x Mass ( particle or wave )

      The electron is held captive by the nucleus

      Why then cannot the electrons themselves be responsible for the production of gravity?

      Then the more matter you have in an object hence the increase in gravity experienced externally?

      Is this a crazy notion?

      In my toroidal Black Hole model it does not require the presence of any solid object as the rotation of the electrons or photons are naturally densified at the epicenter ( forced into a common relative tiny zone in the epicentre where they all have to pass at near value C) . External to this situation the same electrons – photons are held captive by this gravity (strong electrostatic ? ) field created. The overall picture is that the outermost electrons/photons are obliged to reduce their orbit diameter around the epicenter due to this field. They are unable to do this as it would mean they would have to exceed the value of C. The net affect is a conflict between the pull of the epicentural field and inability for the captive particles to move any faster ( similar to the proton in the LHC ) they are naturally obliged to increase their mass (which theoretically could be infinite ) . In short this is the function of such an engine.

      Similarly a cavity magnetron uses a combination of a stream of electrons + magnetic field the outcome is a conversionof energy into microwave. In my model the outcome is gravity.

  41. Evidently, the electron’s mass (and all mass) comes from the Higgs mechanism / scalar Higgs field / vacuum energy. I have no idea where electric charge or electric fields derive or come from, and neither does the standard model. Magnetic fields derive of moving electric fields, and the electroweak and electric forces have been unified, but no one really understands the first thing about what they are. Would there even be value in knowing?

    The Lagrangian that Peter Higgs wrote for the Higgs mechanism simply reproduces (in the first term) Maxwell’s equations, and Maxwell’s equations say nothing about where electric charge comes from. Does it also derive from the vacuum or Higgs field in some way? Faraday didn’t know, so how could Maxwell?

    As you can see, even the current model of particle physics or astrophysics is anything but complete.

    These are just the downsides of having finite minds. There will always be more questions than answers. It will always be easier to understand that something is false than to show that it is true. Truth, like beauty, will always be a value, not an absolute, and ignorance a necessary component of intelligence. What we must ignore is at least as important as what we pay attention to. Try explaining to your computer what a ’1′ or a ’0′ actually is. Could it ever understand? Do we?

    Either, like a microbiologist or a particle physicist, you learn more and more about less and less until finally you know almost everything about virtually nothing, or like an astronomer or astrophysicist, you learn less and less about more and more until finally you know almost nothing about virtually everything. Either way, it won’t all fit between your ears, so don’t even try.

  42. Matt a great site, may I ask a question. The Higgs field seems to be unique in that it is the only field which always has a none zero value ie it is always ‘switched on’. Obviously if this wasnt the case we would not be here but what is so special about the Higgs field that it has to always have a none zero value?

    • There are two parts to the answer:

      1) the Higgs field is the only *elementary* field that is a spin-zero particle. It’s therefore the only field that you could turn on without breaking rotational invariance in empty space. You could turn on electric fields, in principle, but those would point in a particular direction. And you can’t “turn on” fermion fields, like electron or quark fields; because of the Pauli Exclusion principle, essentially, such fields have to remain always very small.

      2) However, why the Higgs field has a non-zero value isn’t known. It’s average value *could* have been zero. We’re still trying to understand why it’s not zero, and, given that it isn’t zero, why isn’t it huge, so large that elementary particles are almost black holes?

  43. Matt, say for instance you had two entangled particles and had access to a black hole, took one and threw it in and kept the other one outside of it, even across the universe. Would they still be entangled? Would a change in one still affect the other? How? Your opinion and would that be a transfer of information?

  44. Both particles remain entangled (a superposition of quantum states) until the spin of one, in this case, the free one is observed. Thereafter, they are no longer entangled, which is to say, changing the quantum state of the free one can no longer affect the quantum state of the one trapped at or near the event horizon. The symmetry of the entanglement is in essence broken by interaction with the event horizon of the black hole. Is this not the scenario (with virtual photons) for which Stephen Hawking has won acclaim for predicting the black body spectra of black holes?

    Although entanglement certainly exists between electron pairs in the same orbitals of atoms, other forms of entanglement have been the subject of much discussion and conjecture in the last few decades. Claims of the possibility of superluminal entanglement communication and teleportation are just two examples. It should come as no surprise that string theory makes some of its boldest predictions with respect to this phenomenon, no doubt because it is impossible to test in a manner that does not yield results as ambiguous as the superposition of quantum states it claims to resolve.

  45. It’s always fun to speculate on impossible questions. My answer would be through wormholes.

    • Maybe but if so many or 1 entire civilisation is going to have a problem with their sun and produced such a thing – surely? We would see it or some local space disturbance?

      • I would expect that the worm holes already exist, the problem being how do we gain access to them. The Universe being like a mass of rising dough, airy and full of holes to everywhere, from within.

  46. Exactly the problem (the ‘full of holes’ part of wormhole theory).

    Wormholes, if something like that could theoretically exist, would be a throwback to Newton’s idea of absolute space and time. Otherwise, my five next questions would be: 1) are the ends of the wormholes: moving, stationary, or accelerating, and 2) relative to what? 3) Would one end of a wormhole created on Earth orbit the sun? 4) Why? 5) What do clocks and yardsticks do at either end, or in the middle of a wormhole?

    In parallel or fictional bizarro universe, or in the phantom zone, things like wormholes might just be possible, but not in this version of reality.

    I’ll allow that the idea of wormholes are fodder for science fiction, as Edward has already suggested. Time travel, to the past would violate conservation of energy each and every time a traveler ended up in a past where an earlier version of the him or herself already existed. Time travel to the future is possible using special or general relativity (just go on a very fast round trip, or hang out for in a region of very high gravity for a long time. This violates no conservation laws, and requires nothing like a wormhole.

    A better question is why hasn’t someone long ago revoked Kip Thorne’s physics PhD for publishing papers about such nonsense as wormholes? Or at least, replace it with something like a HUGO award.

  47. The Universe is a great big wonderful place and I really believe given time, resources, and the knowledge, we will travel the length and breadth of it, in it and through it, by worm holes or other means.

  48. I have a question. Maybe it has been answered in a previous post, but I haven’t seen it. Is the Universe creating new space and I presume space is something, perhaps being the fabric that the Universe is painted on , as it expands or is it stretching already existent space and would it make any difference?

    • Oh God sorry I think I may have been responsible for using the Term New Space here. Prof Matt will be most put out! It is my belief ( only me as far as I can tell ) that New Space is being created second for second and is responsible for the limit on value ‘C’ speed of light. And when considering things like Lorenz contraction etc it is nothing more than a Phase relationship with the rate at which New Space is being created versus the motion of a body in it ( light in this case or a man in a near lightspeed spacecraft ). Also is now causing confusion regards the understanding of the Higgs Field if there is such a thing. All this may be my delusion so must be treated with utmost caution. To continue if Higgs Field does exist I believe it is not Higgs field as imagined but the very mechanism which is causing the New Space to be created and it’s constant emergence, as it would cause a very substantial energy density which may further describe as the mechanism for Dark Energy. But again all this to be treated with caution. I wrote and published an essay March 2012 where many of these notions where identified including the importance and role of constant time in the Spatial background – not to be confused with temporal clock time. Prof Matt Strasler will not be at all happy you have picked this Term as he does not like me or anyone promoting or sharing esoteric opinions here. I am not a physicist – maybe an amateur one at best. These notions came to me having rediscovered Newton Christmas last year and in his book he has one compelling quotation which makes one think about all that has been said and understood about the universe as we understand it.

  49. For those who may be interested in Scott Adams (Dilbert fame) expanding universe theory (similar to this discussion), I finally found it again here:

    • Anyway, this is meant to show us that our sense of time moving forward is merely an illusion. Yes I go along with that one. If we live in a environment of constant time every (Temp T )event referenced to it all happens at the same time. There is no past, present and future they are illusions in of our time. Introducing parallel universes at which point I am jump to the next paragraph. We invent parallel universes in the same we invent String Theory because we cannot move forward in our understanding of what is actually happening out there. Then again I definitely run with concept of duality. Whatever the solution there shall always be 2 ways of expanding each solution so in that respect we are destined never to know. Thanks to Heroditus the Greek philosopher. What troubles me about Einstein Scalars & Tensors is that it is only a way to predict why the road changes direction without explanation why or how it changes direction that is the frustrating bit so we have not moved further forward than Newton really.

      What if, says Adams, instead of gravity being an attracting force, it is merely the doubling in size of all objects every second – yes I like that idea to! – that could go on forever I was thinking about the very same thing the other day. But does not explain the ability of attraction.

      if we break a molecule in half and separate the two halves by any distance we care to choose, the pieces still exert an instantaneous effect on each other. Yes I can run with this idea also. But all the other half molecules just the same without descrimination. I believe in a universe which is based upon a means of information exchange inc gravity and is most likely gravity. Every object no matter what scale has an information duplication of itself and as the New Space emerges that information shall move away from such an object in all directions at value ‘C”. Eventually the information coincides with information with other bodies at which point there is communication from one to the other. Every second or tiny part of second every object is having itself duplicated by means of information. Hence the so called GP B misunderstanding regards frame shifting. They are not being shifted, the information from the Earth as measured by the Gyros was historic at temporal simultaneous second 1. Time and Lightspeed determine that the gyros where receiving old information ( good as it was ). So of course it appears that the gravity of the Earth has shifted. But if one thinks about it not really shifted just that the Earth has moved and it took time to reach the GBP gyros. The information from the Earth in the simultaneous second by the time it arrived at GP B was very old.

      Expansion theory reference is deleted from wiki ! as nonsense so whatever it was I will never know.

    • heat and cold may appear to be opposites at first glance, but in truth they are simply varying degrees of the same thing.

      In much the same way the 3 dimensions where we may only have the 1. But we cut it up into the 3 on an idea born 600 years BC

    • Seeing things from only one perspective is a trap that keeps you locked into one aspect of a condition, like a horse with blinkers it can only see one perspective of experience.

  50. Hi Matt, congrats on your excellent articles on particle decay which I very much enjoyed. I have a question on free neutron decay (just to take the simplest example). Feynman diagrams often show the transition of a down quark to an up quark producing a W- boson, and it is actually the W- boson that decays to an electron and electron anti-neutrino. All good, but the mass of the W- boson at about 80Gev is much greater that the parent neutron, and far far greater than the energy/mass carried away by the electron and antineutrino. So:

    A) where does the energy come from to create the massive W- boson
    B) where does it go?

    [Also:Given the very short range of the weak force compared to the size of the neutron am I right to assume that the W- boson is created as a W field ripple inside the neutron and then decays, leaving the electron and neutrino free with enough energy to escape?]

    • Did you read my article about “Virtual PArticles”, and how they’re not particles at all, but more general disturbances in fields?

      The W “particle” that appears in the Feynman diagram is NOT a real live W particle. It is a disturbance in the W field. There is no need to create the 80 GeV required to make a real live W particle, because there isn’t one. There’s no real live W particle decaying to an electron and an antineutrino. Instead the down quark turns into an up quark and a short-lived disturbance in the W field — one which has less than an MeV of energy — and which quickly transforms into an electron and an antineutrino.

      The fact that the disturbance is so far from being a real W particle — it has so much less energy than a real W particle would have to have — is the main reason why neutron decay is so slow.

      By contrast, a top quark decays to a bottom quark and a real W particle (with 80 GeV or more of energy) which in turn may decay to an positron and neutrino. In this case, the decay is extremely rapid — almost 30 orders of magnitude faster than is neutron decay!

      • Thanks professor, your answer clears that up nicely. :>
        I have read your article on virtual particles some time ago and found it very enlightening (unlike almost all of the popular literature).
        I will keep reading and trying to understand the maths around Feyman’s rules…


  51. Matt will you be posting a commentary to Hawkings recent thoughts on the Blach Hole firewall paradox and grey event horizons. This story seems to have shaken up the physics community

  52. As I understand it, Hawking has only proposed a “softer” version of an event horizon, instead of a “firewall” for such singularities. It would still encapsulate space-time within, but a softer boundary allows for quantum virtual particle fluctuations in accordance with the findings of the Higgs discovery. Even if time ceases to exist for baryons, the Higgs field which gives mass to the boundary as well as everything inside is relatively unpertubed. Makes sense. You probably should ask an astrophysicist about Hawking’s conjecture but under the circumstances, Hawking himself would be the foremost authority. None of what he said negates the excellent work he did on black hole blackbody radiation; it only alters our model of the interaction at the boundary a little. On average, it is the same symmetry-breaking mechanism.

    At last, some meaningful changes to the rest of science and theory are beginning to happen as a result of the Higgs discovery.

    In this universe, you may have as much energy and time as you wish. Only mass and space are limited. This is because with sufficient mass present, the boundary Hawking is proposing is formed, and everything inside is encapsulated. Want to re-think the BB theory from first principles now, anyone? On the other hand, enough energy for many universes already exists and is bound up in the Higgs field. A value for the energy of the vacuum just got an upgrade also.

    You read it here first.

  53. Hooshang Haghbin

    Consider an empty infinite space time. Is it a solution to Einstein’s equation?
    If so, then it exists. Now introduce a “void” in it. How do represent this new space time in the language of “metric”?


    • Hi Hooshang – interesting question

      But GTR & STR are based upon the ability of 3+1 dimensions.

      Supposing we only have 1? And have not come to realize it yet – thanks to all the classical historic physics.

  54. Hooshang Haghbin

    I mean a 4 (or 10)-dim. void, not 1.

  55. Garcol Equphrates

    wormhole, quark, gravity, entanglement…?
    This is behind a paywall for which I have no access. Comments?

  56. Question about the Higgs potential:

    None of the diagrams I have seen indicate the actual energy of the stable point at the bottom of the Higgs / Goldstone potential. Goldstone evidently thought it was zero, but since we now know that the energy needed to dislodge a Higgs boson is 126 GeV, the vacuum energy must be more than that, as there is also the energies of other virtual particles flying around in there to consider. I’ve seen some estimates of 245 GeV submitted as an estimate, but there is never any indication as to whether this number has changed, nor even a rough estimate yet as to how these numbers might affect the estimate of 10^116 GeV for the energy of the vacuum. Any ideas? (You needn’t guess if the theory isn’t there yet- just say so.)

    • The energy of the vacuum isn’t just given by the bottom of the Higgs potential. It gets many other contributions. Or said better: when you’re just trying to understand the Higgs particle’s mass, you can focus only on how the potential of all fields varies when you change the Higgs field a little bit. But if you want to understand the energy of the vacuum, you have to remember that the potential depends on many fields — including many fields that probably exist that we don’t know about yet, and also fields like the quark-antiquark condensate (a composite field that forms during a phase transition in the early universe), etc. There’s no measurement we can make in the lab that measures that energy. The only measurement we can do is see how rapidly the universe’s expansion is accelerating… but strictly speaking, that only measures the response of gravity to the energy of the vacuum. You can only infer the energy of the vacuum from the acceleration of the universe if you assume general relativity is correct… a reasonable assumption, but one that could be questioned.

  57. In conventional Schrodinger Equation of Quantum Mechanics, derivatives are taken with respect to components of space time 4- vector X=(t, x). The ψ gives the evolution of the physical universe in space time. Hamiltonian and momentum are the generators for translations in time and space, respectively.

    Consider, instead,

    (1) i∂μ[ψ(P)]=Hμ[ψ(P)], μ=0,1,2,3.

    where derivatives are with respect to components of energy momentum 4-vector, P= (E, p). What are the physical interpretations of H in (1)? Do equations (1) give the evolution of space time (universe?) in energy momentum space? Does the ψ in (1) gives the quantization of space time Are time and space operators, the generators for translations in energy and momentum, respectively?

  58. Daniel Shawen

    Thanks for your carefully considered and detailed answer, which seems to be very much in accordance with all of the applicable math and physics.

    This month I will be presenting on the Higgs discovery to an august group which will include at least one expert (a particle physicist specializing in neutrinos). After reading the books from Leon Lederman, Sean Carroll, and Nicholas Mee, that was really the only remaining question I had for which there seemed to be no definitive answer.

  59. Tony (Racz) Rotz

    Every night, or some nights or all too few nights nowadays, I tend to gravitate towards my wife, unfortunately, perhaps too often, she puts up an anti gravitational force field. Could there be something similar in nature that restricts the energy of the vacuum or does my question make any sense?

  60. Tony (Racz) Rotz

    I didn’t think you would.

  61. Has Cosmic Inflation Been Proved?

    by Dr. Danny Faulkner, AiG–U.S. on

    March 17, 2014



    According to the big bang model, the universe suddenly appeared 13.8 billion years ago in a very dense, hot state that expanded into the universe that we see today. Based on this assumption, the big bang model predicted that the universe ought to be filled with radiation in the microwave part of the spectrum having a temperature of only a few Kelvin (K). This radiation, referred to as the Cosmic Microwave Background (CMB), supposedly comes from a time a few hundred thousand years after the big bang. In 1965, two astronomers announced the discovery of a 2.73 K temperature radiation field coming from every direction. This was hailed as proof of the prediction of the big bang model, and so most scientists came to embrace the big bang as the origin of the universe.

    Proposing Cosmic Inflation

    However, cosmologists realized that there were problems with the CMB. One of these was the horizon problem: the CMB observed from opposite parts of the sky had precisely the same temperature. But how could that be? Those positions opposite one another had never had a chance to exchange heat, so how could they have come into thermal equilibrium (i.e., have the same temperature)?

    More than 30 years ago, a theoretical physicist named Alan Guth suggested cosmic inflation to solve the horizon problem. According to the theory of cosmic inflation, 10-34 seconds after the big bang the universe briefly and rapidly expanded, or inflated, to a much larger size with a velocity far faster than the speed of light. This would allow the entire universe initially to be in thermal contact so that it could come into the thermal equilibrium before being pulled out of thermal equilibrium by inflation. Cosmic inflation had the added benefit of solving another difficulty with the big bang, the flatness problem. After much discussion, cosmologists came to embrace cosmic inflation, although there has been no evidence for inflation.

    Evidence for Cosmic Inflation?

    Today, a team of scientists announced what they think may be the first evidence for cosmic inflation. This work is based upon a certain kind of polarization in the CMB. Like any other electromagnetic radiation, the CMB is a wave phenomenon. Most waves vibrate in all directions, but sometimes waves can vibrate more in one direction than in others. If so, we say that the wave is polarized. Electromagnetic waves can be polarized different ways. Different physical mechanisms can polarize electromagnetic waves differently, so by studying how and to what degree the radiation is polarized, we can gain clues as to what physical mechanisms may have been involved.

    According to the big bang model, cosmic inflation may have imprinted a certain kind of polarization in the CMB, and several experiments are now operating to look for the polarization predicted by these models. Today’s announcement is the preliminary result of one of these experiments. However, cosmic inflation is not a single theory, but rather it is a broad theory with an infinite number of variations. Thus, it may not be proper to claim that this discovery proves inflation. Rather, it may merely rule out some versions that cannot be true.

    Our Response

    This announcement undoubtedly will be welcomed as the long-sought proof of cosmic inflation so necessary to the big bang model. Biblical creationists know from Scripture that the universe did not begin in a big bang billions of years ago. For instance, from God’s Word we understand that the world is far younger than this. Furthermore, we know from Genesis 1 that God made the earth before He made the stars, but the big bang requires that many stars existed for billions of years before the earth did. So how do we respond to this announcement?

    First, this announcement may be improperly understood and reported. For instance, in 2003 proof for cosmic inflation was incorrectly reported and a similar erroneous claim was made last year. Second, the predictions that are being supposedly confirmed are very model-dependent: if the model changes, then the predictions change. Inflation is just one of many free parameters that cosmologists have at their disposal within the big bang model, so they can alter these parameters at will to get the intended result. Third, other mechanisms could mimic the signal being claimed today. So, even if the data are confirmed, there may be some other physical mechanism at play rather than cosmic inflation.

  62. Tony (Racz) Rotz

    @C Jenk, Creationists are trying to make the Bible into a science book, they are very, very wrong, science it is not.

    • Science is changing and like everything else on this planet is subject to evolution. Nothing can be taken too literally. Except obvious things like the sun appeared this morning. But it may not tomorrow we have no guarantees just it’s history to give us comfort. Our past ( all of it ) is how we determine today what we are today.

  63. A tunneling Higgs phase change could happen everywhere tomorrow, and this wasn’t confirmed until we measured its mass. It could have turned out to be massless, like the Goldstone boson. Only recently did we learn that Higgs actually existed, and as Sean Carroll so aptly observed, almost overnight people stopped calling it the ‘God particle’ (because it actually existed!). Funny.

    We thought Newton’s laws were assurance that the Earth would not suddenly stop rotating, or the sun fall out of the sky. Solar neutrino flux studies eventually ruled out the sun burning out or going red giant any time soon. It took us 30 years to perfect techniques for accurately measuring all three neutrino oscillations, and they are still not a part of the Standard Model.

    The cold war taught us we could easily blow ourselves and the planet to smithereens with our puny atomic weapons. Near Earth asteroids are yet another threat we previously knew little or nothing about, but even a small one has more kinetic energy than all of the nuclear arsenals in this world.

    There will always be things to fear, and fear and/ or superstition will not fail to fill in any gaps that knowledge does not.

    Perhaps the Christian biblical creationists have invested a little too much of their otherwise respectable faith in scripture borrowed from an older faith that argued about the genesis for 500 years before the birth of their messiah and 1000 years before there was anyone who even called themselves Christian. There has always been an easily distinguishable line between reverence for scripture and idolatry for anyone who is not at risk for the religious (or even scientific) equivalent of OCD.

    • X2 slit experiment.

      Suppose a beam of light or electrons are not actually transmitting in a linear gausian 2 D pattern at all but in a cyclical form which when viewed from one perspective they would look like the former. Supposing the detectors they used in each slit actually polarizes the light/electron pattern then obliged to form a particle character? Light may prefer to travel in a straight line as we understand but how do we know it is not actually moving in 2 dimensions simultaneously?


    • To really confuse things further lets set up an experiment ( classical one ) but the electron is expressing 4 degrees of trajectory and see what happens just for fun. i.e. it is moving ( radial) cyclical and linear = what happens then? What pattern do we observe?


  64. Tony (Racz) Rotz

    A spiral rising at a 4 degree angle?

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