What Physicists Don't Tell

If you know the answers to any of these questions, then please, please contact me and tell all!

Scientists love to tell us ordinary folk about their great discoveries, and they work hard to dumb it all down for us. But sometimes they go too far and leave little questions unanswered. There are quite a few such questions that I have long wondered about but never found any explanation beyond vague references to incomprehensible equations. My suspicion, borne of long experience as a technical writer, is that physicists don't explain them because they haven't thought about them clearly and don't actually understand the various inconsistencies they have drawn from their equations. They have, perhaps unconsciously, steered past the issue and thus avoided a reality check on their pet theory. Or, am I being unfair? This post raises a few such inconsistencies that spring to mind, I am sure there must be plenty more where these came from.

Contents

Electricity and magnetism

It has long been known that electricity and magnetism are the two curious partners in electromagnetism. Changing an electric field creates a magnetic field and vice versa. As the two changing fields interact they make each other oscillate to and fro, creating a wave of electromagnetic energy which travels off at the speed of light.

Relativity goes a step further still, merging the descriptions of these two fields into a single electromagnetic entity.

Meanwhile quantum physics shows that the electromagnetic field is quantised, being made up of particle-like photons.

But we can also have static fields. The field round a magnet is static, it is not radiating energy off anywhere. The same goes for the static electricity on a balloon that has been rubbed on your hair and stuck to the ceiling. These fields store energy, sometimes in huge amounts. Only when something moves (relatively) through the field, will the change of state set off the other field too, and electromagnetic photon energy be exchanged between the field and the moving thing.

Quantum physicists at first tried to describe these static fields as special kinds of photon. But what kinds of photon? What is so special about them? How come you can trap photon energy like that? I read once that they can be thought of as polarized in a special way, perhaps in another "direction" than ordinary space. What way is that? The author waved his hads and moved swiftly on. I also once read that these are "virtual" photons, continually being emitted but then reabsorbed before they can do anything. Yet, unlike the more usual virtual particles, their lifetime is not limited by Heisenberg's uncertainty principle; these static fields can extend indefinitely, yet at the flick of a switch decay into a blast of short-wave radiation. And clearly, when I hold one magnet near another, the field is exerting a steady force which is many orders of magnitude greater than say the Casimir effect.

And there is another big problem here. As quantum physics continued to develop, it showed that magnetic fields are quantised but that electric fields are not. This appears to flatly contradict the relativistic treatment of the two fields as different aspects of one and the same thing. As far as I can tell, the quantisation of magnetic flux is only detectable experimentally in superconductors. Might it be that the apparent quantisation is a side-effect of the quantised electrons generating the flux and not an intrinsic property of the flux itself? Why are physicists silent on this conundrum?

Our most sophisticated quantum picture, quantum field theory (QFT) descrbes a zero-point field for each fundamental force, with an individual quantum comprising a disturbance or excitation of the zero-point field. For example a photon is an excitation of the photon field. But QFT has no model of how these electrostatic and magnetostatic excitations happen. Some kind of substantial quantum field would have to be present, but quantum theory merely hands over to classical theory and has nothing more to add.

So why does everybody pretend that QFT explains everything? Why is modern theory's utter failure to address the central mystery never acknowledged?

Negative energies

It is often explained that gravitational enegry is negative. The argument goes that it increases as two objects fall towards each other and the gravitational field between them intensifies, reaching its strongest just as they collide. But at the same time they have been falling faster and faster, increasing their kinetic energy of motion. Energy must be conserved overall, so the only answer can be that, as the kinetic energy gets more positive, the gravitational energy gets more negative to balance it out. And since the gravitational energy is also getting stronger, the only way it can get both stronger and less positive is by being negative already. All this is a consequence of the nature of gravitation as an attractive force.

That is all very well, but it suggests to me that any attractive force should similarly involve negative energy. Consider for example the attractive forces between positive and negative electric charges, or between north and south magnetic poles. These obey much the same laws of attraction that gravity does and they behave in much the same way. Does this mean that the energies stored in these fields is also negative? On the other hand, like charges or poles repel, so these fields must be positive. Does flipping a magnet round really swap all its stored energies between positive and negative? That would surely explain the energy involved in making the flip, another detail at best left barely acknowledged, never properly explained.

Going deeper into the atom, the weak nuclear force attracts protons and neutrons to each other in the atomic nucleus. More negative energy? On the other hand the strong nuclear force, which attracts quarks within a single such particle, bizarrely increases with distance; as you put in energy to pull quarks apart, you increase the strength of attraction, so it must presumably be positive energy.

Yet nobody ever explains that the energies of these other well-known attractions are therefore negative, never mind how the theory of electromagnetism involves both positive and negative energies.

Why do physicists love to bang on about gravitational energy being negative, but never mention the others? Why are we never told the whole story?

The energy of the Universe

It has often been pointed out that the balance of positive and negative energies in the universe is a very close one. We find ourselves on a cusp where either might just dominate. Positive energy such as mass and light causes positive curvature of spacetime, which is associated with the universe eventually collapsing. Negative energy such as gravity causes negative curvature of spacetime, which is assoiated with the universe expanding forever. Since the two so nearly balance out, the net energy of the universe is close to zero. The law of energy conservation therefore implies that the universe never had much to begin with, if any. It must all have just exploded out of nothing, positive mass and negative gravity appearing side by side. As it expands, the decrease in negative gravitational energy is balanced by an associated slowing of the expansion rate and reduction in kinetic energy of the galaxies flying apart. It is all very neat and symmetrical – as far as it goes.

But other, less balanced forces are also at work. We now believe that the early period of inflation was driven by an inpouring of "dark" energy, and in recent aeons that expansion has started to speed up again due to more of the same. That dark energy is both speeding up the expansion rate, adding kinetic energy to everything that is flying apart, but as things get further from each other the negative gravitational potential between them decreases. That amounts to a double-dose of positive energy. Today we reckon the extra, "dark" energy to comprise about 70% of the universe's total energy (positive + negative). Scientists are honest enough that they have no idea where this vast inpouring of dark energy is coming from, but they insist that it is.

But they seem less inclined to talk about how dark energy affects that neat balance between positive and negative. After the arrival of 70% extra positive energy, we are today balanced on that cusp of zero net energy, where spacetime is still flat on the grandest scale we can yet measure. The implication is that in the past, negative energy must have massively dominated. Startlingly unlikely coincidence? Or is somebody missing something here? Why don't cosmologists like to talk about it?

An absorbing corollary

One of physicist Richard Feynman's many claims to fame is his sum-over-histories approach to quantum theory. He showed that if you take all the possible outcomes of a given initial state, then adding together the probabilities for every individual possibile path to a given outcome should leave you with the probability for that outcome. Mathematically at least, some of these paths can be insanely weird, traversing points all over space and, indeed, all over spacetime. In fact, the majority of them are. Remarkably, the weird paths that traverse the past neatly cancel out the weird paths that traverse the future, just leaving the expected ones, so you don't have to make any restrictive assumptions about the final wave of probabilities.

There is no known boundary to space but there is to time. What happens with paths that reach all the way back to the Big Bang? Feynman and his mentor John Wheeler thought it reasonable to assume that if time begins somewhere then it must end somewhere. If we assume the paths just bounce back off the ends, the maths no longer gives sensible answers. So they instead proposed that these ends of time acted as perfect absorbers, that no possbile path could bounce back off them. However nothing can be so easily destroyed, so the possibilities had to somehow be re-emitted. They reappeared with their phases randomised, much like black-body radiation. When they met back in the present, their phases meant that they neatly cancelled each other out again and the theory worked again. This mathematical embellishment became known as Wheeler-Feynman absorber theory.

Fast-forward now to Stephen Hawking's investigations into imaginary time. As mentioned above, one of its more curious consequences is to flatten out the Big Bang so that it is not so much a sharp point as a pole on a gently curved spacetime "surface", much like the South Pole on the surface of the Earth. It did the same for a Big Crunch at the end of time.

In Hawking's universe there is now nowhere for the Wheeler-Feynman absorbers to go. Paths from the future can go back to the Big Bang or forward to a Big Crunch and freely cross over the poles to return to the near-future after all. The mechanism to randomise their phases is no longer there, so are they randomised or mutually cancelled in some other way? Does the maths still hold up?

Information

Some theoretical physicists are so enthusiastic about information theory that they are coming to regard it as a fourth pillar of modern physics, following thermodynamics, relativity and quantum theories. But I find a fundamental inconsistency between these theories.

Thermodynamics has a concept called entropy, sometimes characterised as disorder. It is a fundamental law of thermodynamics that entropy never decreases but can only ever increase, which it does inexorably over time. Many physicists treat information as being much like entropy, on the grounds that a low-entropy state is highly ordered and therfore contains little real information. On the other hand a highly disordrered system is in a high state of entropy and needs a lot of information to describe it fully. The correspondence is so close that the size of a black hole, as given by the area of its event horizon, is a measure of both the entropy and the information that the hole has swallowed. The entropy of the universe has vastly increased since the Big Bang and therefore the information it contains must have increased.

Quantum theory also has a concept of information. The properties of any given quantum naturally carry information, and information is transmitted when a quantum travels from one place to another. Shannon's law describes how much information can be carried by say a beam of light. When two quanta interact, the information may be radically transformed but it is never destroyed. Since quantum mechanics is time-symmetric, information can never be created either. Therefore, throughout any sequence of quantum interactions, the total amount of information in the system must remain constant. The amount of information in the universe must therefore have remained constant since the Big Bang.

There is a glaring contradiction between these two pictures. Is the amount of information in the universe ever-increasing, or is it constant and unchanging? The processes described by thermodynamics are classical processes, but in practice such a process is an aggregate sum of untold numbers of individual quantum events. Consider now some such event where entropy increases, such as dropping a glass on the floor where it shatters into dozens of pieces. According to quantum theory each and every minuscule part of that shattering process conserved information, so the total amount of information can not have changed either. But according to thermodynamic theory, since its entropy has increased then the total information to be gained from all those pieces will have increased too. A watered-down version of the theory describes entropy as the "capacity to hold" information, so that although a shattered glass can hold more information than a whole one, it does not have to. But that grossly breaks the precise mathematical correspondence between the area of an event horizon, its entropy and its information content. Why should a black hole stuff itself chock full of information when a broken glass does not have to?

Can information increase or can't it? Is there really a way to resolve this ridiculously glaring anomaly?

Updated 30 June 2023