I recently commented on an astrophysicist’s blog regarding a claim I consider ahistorical and inaccurate. The comment was deleted. I don’t have a problem with that – a blog is a personal space. However, I was responding to a specific claim about the origin of General Relativity that is both common and false. What follows is the one paragraph remark I was commenting on and my now-deleted response which admittedly ranges a bit further than simply refuting the quote requires:
The equivalence of inertial mass with gravitational charge is a foundational principle of general relativity. There are flavors of GR in which it falls out explicitly, e.g., Yilmaz’s gravity. But it is basically an assumption.
The equivalence of inertial and gravitational mass was an observed and measured fact known to Galileo and Newton. It was not an assumption of GR. The mid-20th century extensions of what is now called the Weak Equivalence Principle were little more than conjectures of mathematical convenience “suggested” by Robert H. Dicke. They had nothing to do with the development of GR.
Along with John A. Wheeler’s aphoristic, empirically baseless, invocation of a causally interacting spacetime, Dicke’s two extensions of the WEP were surreptitiously hung on Einstein’s General Relativity producing a grotesque variant that by rights should be known as Dicke-Wheeler Relativity Theory. It is DWRT that has been the officially taught version for the better part of 50 years although the D-W distortions are almost always attributed to Einstein. He would have puked.
It is DWRT that prompts otherwise rational people to insist that, despite theoretical and empirical evidence to the contrary, the speed of light is some sort of universal constant. It is DWRT that promotes the false claim that Einstein explained gravity as being caused by the curvature of space.
As far as space itself goes, it is a relational concept exactly like distance. That is all the evidence supports. In fact, space is best understood as the aggregate of all distances that separate you from all the other things in the Cosmos that aren’t you. Substantival space is a mathematicist fiction that has no scientific basis.
Throughout the Cosmos, everywhere within our observational range where there is no matter there is only electromagnetic radiation. That is an empirical fact. Everywhere people imagine they see space there is electromagnetic radiation. At any given 3D location that radiation is flowing omnidirectionally from all the omnidirectional emitters (stars and galaxies) within range. That is what we observe and that is how we observe.
As Mach surmised we are connected to the rest of the Cosmos or at least to those objects within range. That non-simultaneous connection is via electromagnetic radiation – that is what’s there. Until recently no one had bothered to do a full survey of what might be called the Ambient Cosmic Electromagnetic Radiation. The authors of this interesting paper seem to think they are the first. Everybody else was too busy looking for some dark stuff apparently.
Modern theoretical physics is all theory and no physics; it consists of nothing but the unrelenting and fruitless effort to prop up two inert century old models whose assumptions of mathematical convenience were lapped by physical reality decades ago. Tinkering with obsolete mathematical models does not constitute a scientific endeavor even if that is all that has been taught for the last 40 years.
“If we ever want to go beyond our current understanding, any alternative theory has to not only reproduce all of our present-day successes, but to succeed where our current theories cannot. That’s why scientists are often so resistant to new ideas: not because of groupthink, dogma, or inertia, but because most new ideas never clear even the first of those epic hurdles, and are inconsistent with the established data we already possess.“
Strangely enough that is a pretty good description of why modern theoretical physics appears to be in fact quite dogmatic and inert. If new ideas can be dismissed for not immediately clearing the “epic hurdles” that theorists prescribe, then they amount to nothing more than preemptive barriers to new ideas. This greatly favors the orthodoxy.
No research funding is available for new ideas that don’t hurdle the barriers. They function as a defensive bulwark protecting the standard model from unorthodox incursions.
The only new ideas that are quickly adopted are those that fit the old model to new data. The favored model can be continuously revised (new epicycles, dark matter, etc.) into agreement with unpredicted new data. The “epic hurdles” only apply to new ideas that challenge the orthodoxy. New ideas needed to salvage the old model are adopted without reservation.
And so here we are, stuck with a cosmological model that is in an exactly analogous situation to that which existed with respect to Ptolemaic Cosmology prior to Kepler. Ptolemy’s model could be massaged into agreement with most observations and repeatedly tinkered into agreement with new, more accurate data, but only to some degree. So it is with the Big Bang model. Math is like that, but math is not physics.
Like PC, the BB model has at its core two fundamental misperceptions about the nature of physical reality. PC assumed geocentrism and that bodies orbited the earth in perfect circles. Only once geocentrism and perfect circles were set aside could science advance.
The two misperceptions underlying the BB are first, that the Cosmos can be mathematically modeled as a simple, unitary, simultaneously-existing entity – a Universe. Secondly, the observed cosmological redshift can be attributed to some form of recessional velocity. The inevitable consequence of those assumptions is an Expanding Universe model – the BB.
The first assumption has been falsified by known physics. The speed of light has a finite maximum such that it requires light from the most distant objects we currently observe more than 10 billion years to reach us. It therefore follows that we have no knowledge of the simultaneous state of the Universe because it is physically impossible to have such knowledge. It is a metaphysical conceit, not a demonstrable scientific fact, that such a Universe even exists.
The second assumption is false because it depends on the first being true. It is meaningless to assume something that requires something that does not exist (the Universe) to have a property (expansion) that cannot possibly be observed.
As was the case in Kepler’s time, the only solution to the dogmatic inertia that cripples modern cosmology is to discard the foundational assumptions of the standard model and start over, by rigorously assessing the data on hand without the distorting blinders of the old model.
Over the last century there has been an enormous increase in our knowledge of the Cosmos but due to the dogmatic inertia of the scientific academy all of that new knowledge has not generated any new ideas because it has all been run through the meat-grinder of the standard model. The result has been a dogmatic and inert BB model that describes in excruciating detail a Universe that does not exist and bears no resemblance to the Cosmos we actually observe.
Kepler had an advantage that modern researchers do not – he was not dependent on the dogmatic and inert modern scientific academy for funding. Modern cosmology will remain an unscientific digression into prescientific orthodoxy until it’s research funding is driven by the physics researchers investigating, by observation and measurement, physical reality.
Theoretical modelers in such a system would be required to produce models that reflect the physical phenomenon uncovered by physics researchers. The math must follow the physics if cosmology is to be a science.
The failed Big Bang model needs to be consigned to the dust bin of history where it can serve as an object lesson in how not to do science.
Here are some choice tidbits from a recent Tim Anderson article titled Zero-point energy may not exist. I’m always supportive of any effort to drag theoretical physics back into contact with empirical reality so the suggestion that ZPE may not exist is at least promising. It even suggests the possibility that modern theoretical physics might emerge from its self-imposed exile in Plato’s cave, the cave-of-choice in this case being mathematicism.
In reading the article any hope of a scientific restoration is dashed, as one is quickly immersed in sea of mathematicist illogic. Here for instance is the “reasoning” that underlies the ZPE concept:
…it means that nothing has non-zero energy and because there is an infinite amount of nothing there must be an infinite amount of energy.
While it is clear that the author is distancing himself from the ZPE concept, that account of the underlying “reasoning” gives rise to the simple question, how did such flamboyantly illogical nonsense gain any traction in the scientific community? The answer of course is mathematicism which is itself a flagrantly illogical proposition, just not recognized as such by the denizens of the mathematicist cave. Then there is this little gem (emphasis added):
Quantum field theory, which is the best theory of how matter works in the universe that we have, suggests that all matter particles are excitations of fields. The fields permeate the universe and matter interacts with those fields in various ways. That is all well and good of course. We are not questioning that these fields exist. The question is whether a field in a ground state has any measureable effect on matter.
So in their “best theory” the universe is permeated by many fields and matter is an excitation of those fields. Physical reality however only contains one observed field and that is the electromagnetic field which is the aggregate of all the electromagnetic radiation that permeates the Cosmos. That radiation is constantly being emitted by all the luminous matter that also permeate the Cosmos. There are no additional observed fields as described by QFT.
Despite the fact that the QFT fields are not observed the author does not wish to question their existence. Why? Mathematicism, of course. If a math model says something is there and physical reality declines to offer any evidence in support of such a conjecture, the mathematicist position is that the math is correct and reality is perversely withholding the evidence.
Imagine we have a sensitive Hawking radiation detector orbiting a black hole. The detector is in a state of free fall, meaning that it experiences no gravitational forces on it.
This last bit invokes a wholly imaginary thought experiment involving imaginary radiation emitted by an imaginary black hole. Without any empirical basis or logical connection to known physics, it has no scientific significance even if the “experiment” somehow reflects badly on the ZPE concept. In that, it only amounts to an illogical argument refuting an illogical concept.
The second sentence also presents a widely promulgated claim that has no basis in physics. The idea that an observer or detector in free fall experiences no gravitational forces on it is purely unphysical nonsense. An observer or detector can only be in a state of free fall if they are experiencing a gravitational force. The typical basis for this claim is that the observer is prohibited from making observations that would clearly show the presence of a gravitating body and thus demonstrate the presence of a gravitational field.
Einstein is usually credited with this view but in fact his conception of the equivalence principle was highly constrained and did not extend to fundamentally illogical claims like the one made above. The version of the equivalence principle Einstein employed is now called the Weak Equivalence Principle.
The two extensions of the equivalence principle contrived and adopted after Einstein’s death, the disingenuously named Einstein EP (he had nothing to do with it) and the Strong EP have no logical, scientific or theoretical justification. They were merely conjectures of mathematical convenience proposed by the physicist Robert H. Dicke, who along with his colleague John A. Wheeler, concocted a distorted variant of Einstein’s Relativity Theory. That variant is presented today as Einstein’s RT but it is a separate theory and should have it’s own name — Dicke-Wheeler Relativity Theory.
It is in DWRT that you will find the EEP and SEP as well as a reified version of spacetime which is said to causally interact with matter and energy causing the gravitational effect and facilitating the Expansion of the Universe. There is no empirical evidence supporting those ad hoc additions to ERT. They are simply mathematicist conjectures that have no scientific basis or logical connection to physical reality. In modern theoretical physics though, they are treated as axioms — true by definition.
Mathematicism is the principle driver of the Crisis in Physics. The reason for this is simple: math is not physics. The controlling paradigm in modern theoretical physics, however, is that math is the basis of physics and mathematical models determine the nature of physical reality. That paradigm is a philosophical belief that has no scientific basis.
As a consequence of mathematicism theoretical physicists espouse two standard models that describe a physical reality containing a large number of entities and events that are not part of the physical reality we actually observe. Modern theoretical physics does not constitute a science so much as a cult of belief.
You have to believe in the expanding universe, in dark matter and dark energy, in quarks and gluons. You have to believe that the speed of light in a vacuum is a universal constant even though it cannot be measured as such and is not constant in General Relativity — at least according to Einstein.* You have to believe in these things because they are not demonstrably part of physical reality. Scientists don’t traffic in beliefs but mathematicists do and so there is a Crisis in Physics
* The speed of light is a universal constant according to Dicke-Wheeler Relativity Theory.
The light cone graphic below is taken from a Wiki article. The discussion therein gets the basics right, at least with regards to where the concept of a light cone comes from and the dimensional issues with the illustration.
… a light cone (or “null cone”) is the path that a flash of light, emanating from a single event (localized to a single point in space and a single moment in time) and traveling in all directions, would take through spacetime. (…)
In reality, there are three space dimensions, so the light would actually form an expanding or contracting sphere in three-dimensional (3D) space rather than a circle in 2D, and the light cone would actually be a four-dimensional version of a cone whose cross-sections form 3D spheres (analogous to a normal three-dimensional cone whose cross-sections form 2D circles)
That’s fine as far as it goes – with two caveats. First of all, the spacetime term should be understood as referring to a relational concept of space and time, not to Wheeler’s causally interacting spacetime. Secondly, contracting spheres of light do not exist in physical reality. Much of the rest of the article is gibberish well encapsulated by the labeling of the illustration which basically renders the image incoherent.
Observer should be labeled Galaxy. A galaxy (TSV) on cosmological scales emits ESWs of light and absorbs ElectroMagnetic Radiation from all remote sources that can reach it.
Future LC = Diverging Light Cone -essentially a projection of an ESW emitted by a galaxy.
Past LC= Converging Light Cone – the aggregate of all the incoming EMR that can reach a galaxy from remote sources.
Hypersphere Of The Present is an imaginary mathematical construct that does not exist in physical reality.
For starters, the image has an observer at the shared apex of the two cones but an observer is not mentioned in the text of the Wiki article. In terms of physical reality an observer is at the apex of a “past light cone” – the observer observes light emitted from distant sources, usually omnidirectional emitters like stars and galaxies.
The “past light cone” is the aggregate of all the inbound radiation from those distant sources onto the observer. Rather than calling it a “past light cone” it would be more accurate to label it a Converging Light Cone, with the understanding that the light cone is a relative, point-of-view phenomenon that has no physical relevance except with respect to the observer.
The “future light cone” does not have an observer at its apex, it has an omnidirectional emitter such as a star or galaxy there. The “future light cone” is an aggregate of the successive expanding spherical wavefronts of electromagnetic radiation emitted by the emitter. The “future light cone” should be more accurately labeled a Diverging Light Cone. The DLC is a physical entity, consisting of sequentially emitted expanding spherical wavefronts of electromagnetic radiation. That understanding flows from Maxwell and Einstein – it is standard physics
Borrowing from radio terminology the emitter/observer can be thought of as a transmitter/receiver or transceiver (TSV). The term transceiver will also be used for an observer-only by considering a non-transmitting observer (such as a human) to be a subcomponent of a transceiver such as a star or galaxy system. With respect to the space and time (relational) labels of the illustration, the apex can be labeled “Here and Now”. So the apex represents the HAN of a TSV.
The rest of the labeling is adequate with the relational nature of space and time caveat being understood. What the illustration then presents us with is a stark refutation of the modern conception of the Cosmos as a simultaneously existing Universe. The TSV (galaxy) is always and only at some unique spatio-temporal location.
The TSV is at the center of the omnidirectionally expanding spherical wavefronts of electromagnetic radiation that it emits – the Diverging Light Cone. A TSV is also at the center of all the electromagnetic radiation that is arriving at its particular place and time from all directions – the Converging Light Cone.
The following statement applies to every possible TSV – everywhere and everywhen. Every TSV is at the center of its own unique “universe” which is just its own unique view of a Cosmos that cannot be simultaneously accessed from any three dimensional HAN.
No TSV can detect the state of a remote TSV that is simultaneous with its own HAN. The finite speed of light prohibits any and all such knowledge. The nearest galaxy to our own, Andromeda, is 2.5 million lightyears distant. We see it in our frame as it existed 2.5 million years ago. We do not have and cannot have any knowledge of its “current” state. Andromeda’s “current” state is not part of the Cosmos we have access to. Andromeda’s HAN does not exist in our unique cosmological frame – Andromeda is always There and Then (TAT) in our cosmological frame.
The two dimensional projection labeled the Hypersurface Of The Present illustrates this clearly. The HAN of any TSV is always and only a local state. All other spatio-temporal locations lie outward – TAT- along the surface of the Converging Light Cone. No TSV has access to the HOTP and in fact the HOTP is only a mathematical/metaphysical construct that has no physical correlate. The HOTP does not exist in physical reality because it represents a universal simultaneity which cannot exist because lightspeed has a finite maximum. There is no physical meaning to the concept of a “universal now” – that is the reason there is no universal frame or “now” in General Relativity.
The apex point represents the only HAN available to any TSV. All remote objects exist only in the transceiver’s past – on the TAT of the Converging Light Cone.
Unfortunately, modern cosmologists are of the opinion that they do have knowledge of this simultaneous something (the HOTP) that does not have any existence in physical reality. That is what the term Universe refers to as employed by cosmologists. They believe themselves to be in possession of knowledge of this imaginary, simultaneously existing Universe that, by the known laws of physics, cannot exist. That 13.8 billion year old entity does not exist by normal scientific standards – it is not an observable.
What modern cosmologists have, of course, is just a mathematical model based on some simplifying assumptions adopted @ 100 years ago at a time when the known Cosmos barely extended beyond our own galaxy. One of the model’s assumptions is that the Cosmos has a “universal” spacetime frame (the FLRW metric) even though, in the context of General Relativity, no universal frame exists. A universal spacetime metric inherently includes a universal time with a universal now. Despite the incongruency, the FLRW metric was applied to the GR field equations. The result of this misbegotten effort speaks for itself:
The Standard Model of Cosmology is a miserable failure; it describes a Universe that looks nothing like the Cosmos we observe. To the extent that it can be said to agree with actual observations, it only arrives at such agreements by insisting that physical reality contains entities and events that physical reality, by all direct empirical evidence, does not appear to contain.
The SMC is junk science or perhaps more accurately, it is a mathematicist confabulation presented as science by people who don’t understand basic physics – that the speed of light in the Cosmos has a finite maximum of @3×108 meters/second. It’s not that they don’t know that fact, they do, but rather they don’t understand what it means in the context of the vast Cosmos we observe. They only know what the SMC tells them and that model, they believe, can’t be wrong because if it were smart people like them wouldn’t believe in it.
In fact though, we have no scientific reason to think that the limited view of the Cosmos we have provides us with knowledge of an unobservable, simultaneously-existing, and expanding Universe. The consensus belief of cosmologists that they have such knowledge can be attributed to the fever dream of mathematicism that deeply infects the theoretical physics community. Modern cosmology is a mess.
Science is not perfect. Mistakes are to be expected in science. The Standard Model of Cosmology is a mistake. The model’s foundational assumption of an “expanding universe” is a mistake. It is a mistake in the same way that geocentrism was a mistake. It is fundamentally wrong about the nature of the Cosmos, It is time to move on from the expanding universe model. I’ll give the last word to the astrophysicist Pavel Kroupa:
Thus, rather than discarding the standard cosmological model, our scientific establishment is digging itself ever deeper into the speculative fantasy realm, losing sight of and also grasp of reality in what appears to be a maelstrom of insanity.
10May24 Acknowledgement: My original concept for the apex of a light cone was that it should be labeled “Here”. In an exchange with the mathematician Robert A. Wilson he made the invaluable suggestion that the apex be called “Here and Now”.
19Jun22 The following was posted as a comment to this Medium post by Eric Siegel.It has been slightly edited.
This is a good overview of the illogical mathematicism at the root of the inane Big Bang model. The Friedmann equation is indeed the headwaters of all the nonsense that currently engulfs and overwhelms any possibility of a meaningful scientific account of the Cosmos.
The Friedmann equation rests not only on the two simplifying assumptions of mathematical convenience, isotropy and homogeneity, the author cites. There was also an unstated but implicit assumption that the Cosmos could be treated as a unified, coherent, simultaneous entity, a Universe.
Further it was assumed that the field equations of General Relativity, derived in the context of the solar system, could be stretched to encompass this imaginary Universe. The results speak for themselves.
The standard model of cosmology is an incoherent, unscientific mess. It claims that once upon a time 13.8 billion years ago the entirety of the Cosmos was compressed into a volume smaller than a gnat’s ass that began expanding for an inexplicable reason, then accelerated greatly due to the fortuitous intervention of an invisible inflaton field, which set invisible spacetime expanding at just the right rate to arrive at the current state of the Universe, which we are told is 95% composed of some invisible matter and energy that has no other purpose than to make the model agree with observations; the remaining 5% of this Universe is the stuff we actually observe.
To be clear, all of the entities and events the standard model describes are not part of the Cosmos we actually observe except for that rather trivial 5% of the BB Universe. That 5% of the model is the Cosmos we observe.
Science is the study of those things that can be observed and measured. At some point in the mid 20th century theoretical physicists adopted the conceit that science was the study of mathematical models. This categorical error was compounded by treating scientific hypotheses such as “universal expansion” as axioms (true by definition). In science, all truths are provisional; nothing can be held true by definition.
Axioms belong to the mathematical domain. Math is not science and the mathematicist belief that math underlies and determines the nature of physical reality has no scientific basis. That the Cosmos is a unified, coherent and simultaneously existing entity can only be true if the Cosmos had a miraculous simultaneous origin – the Big Bang,
The problem with miracles is that they are not scientific in nature; they cannot be studied only believed in. Believing in the Big Bang and weaving a fantastical account of an imaginary Universe is a mathematical/metaphysical endeavor that has nothing to do with science or physical reality.
Imaginary Universe? That’s right, the Universe of the Big Bang has no basis in any known physics. In the physics we know, there is a finite, maximum limit to the speed of electromagnetic radiation – 3×10^8 meters per second (186,000 miles per hour). It is via electromagnetic radiation that we observe the Cosmos.
The galaxy nearest to our own is Andromeda; it is detectable by the unaided eye as a fuzzy patch in the night sky. Andromeda is @ 2.5 million light years from Earth. Everything we know about Andromeda is 2.5 million years out of date, of its current state we do not have and cannot have any direct knowledge.
At the far extent of our observational range we observe galaxies that are @10 billion light years away. We do not have and cannot have any knowledge of the current state of any of those galaxies. The same argument holds for all the other galaxies we observe.
Galaxies are the primary constituents of the Cosmos we observe. It follows, therefore, that we do not and cannot have knowledge of the Cosmos’ current state. The very idea of the Cosmos having a current state is scientifically meaningless. Mathematicists believe otherwise:
“If you want to understand the Universe, cosmologically, you just can’t do it without the Friedmann equation. With it, the cosmos is yours.“
See that’s all you need, a simple mathematical model derived 100 years ago by “solving” the field equations of General Relativity (which does not have a universal frame) for a simplistic toy model of the Cosmos (that does have a universal frame). Suddenly you can know everything about everything, even things you can’t possibly observe or measure. That’s mathematicism hard at work creating an imaginary Universe for mathematicists to believe in. The standard model of cosmology has no scientific basis; it is a nerd fantasy and it is scientifically useless.
Well here’s a cute little video that manages to do a good job of conveying just how daft and detached from reality theoretical physics has gotten over the last century:
The first 11 minutes or so are effectively a sales pitch for one of the structural elements of the Big Bang Model – Spacetime. The deal is, you’re supposed to believe that the force of gravity is not really there – nothing is holding you to the surface of the earth, rather the earth is accelerating upward and pushing against you.
And the reason this is happening is that you are not following a curved path in –Spacetime, because according to the video you are being knocked off of that curved path by the earth that is accelerating upwards and you are in the way and that’s gravity, tada! How do we know this? Well that’s obvious, it’s in the math and the math tells reality what’s going on and if reality doesn’t like it, that’s too bad. So don’t go trusting your lying eyes, alright.
In addition to Spacetime, this fairy tale is predicated on a ridiculous over-extension of the Principle of Equivalence that Einstein used in developing Special Relativity. Einstein was very clear that the POE applied only under the severely constrained circumstances of a thought experiment. His main purpose seems to have been to provide a physical interpretation for the observed equivalency between gravitational and inertial masses. Einstein presented the POE as informing his ideas about gravity.
The video ignores Einstein’s constraints and pretends the POE is fundamental to General Relativity, so it winds up insisting that things that are obviously not true in physical reality, are, nonetheless, true simply because the math can be framed that way – your lying eyes be damned.
We are told that a man falling off a roof is in the exact same situation as an observer in a non-accelerating rocket ship far from any gravitating body. This claim is made even though it is obviously not true; the falling man will be injured, if not killed, when he hits the ground, whereas no such fate will befall the observer in the rocket ship.
So the idea is, until the falling man meets his unfortunate fate, the situation is the same and therefore both situations are the same, the different outcomes not withstanding – because the math is the same. Observers free falling in orbit won’t be able to tell they’re not in an inertial frame – unless they look out the window, so that’s just like being in an inertial frame too. Right, of course.
In a similar vein, the video insists that an observer in a rocket accelerating at 9.8 m/s^2 will not be able to tell the difference between that situation and standing on the surface of the earth. The presenter fails to mention however, that only holds true as long as the observer doesn’t observe out the window, which will alert the observer that the rocket and therefore the observer are not at rest on the surface of a large gravitating body and therefore the situation is not comparable to standing at rest on the surface of the earth. Also, if any observer steps off the rocket, they will be left behind as the rocket accelerates away. But nevertheless, it’s all the same – as long as no one looks out the window, and maybe you remember that the earth is actually accelerating upwards under your feet, like the floor of the rocket. Sure, of course.
For the sake of introducing some sanity in this matter, here is Einstein on the POE. Note that the second paragraph completely contradicts the claims made in the video implying the equivalence of all inertial and non-inertial frames.
We must note carefully that the possibility of this mode of interpretation rests on the fundamental property of the gravitational field of giving all bodies the same acceleration, or, what comes to the same thing, on the law of the equality of inertial and gravitational mass…
Now we might easily suppose that the existence of a gravitational field is always only an apparent one. We might also think that, regardless of the kind of gravitational field which may be present, we could always choose another reference-body such that no gravitational field exists with reference to it. This is by no means true for all gravitational fields, but only for those of quite special form. It is, for instance, impossible to choose a body of reference such that, as judged from it, the gravitational field of the earth (in its entirety) vanishes.
RELATIVITY THE SPECIAL AND GENERAL THEORIES, ALBERT EINSTEIN, authorized translation by Robert W. Lawson, original version 1916, translated 1920, appendices 3 and 4 added 1920, appendix 5 added to English translation 1954
It is clear from this statement that the POE of Einstein’s thought experiment is the Galilean version, commonly referred to nowadays as the “Weak” POE. The so-called “Einsteinian” and “Strong” POEs of modern cosmology are post-Einstein formulations attributed initially to Robert Dicke, though there were doubtless others who perpetrated and embellished this nonsense. Neither extension of the POE has anything to do with the foundations of Einstein’s Relativity Theory. It is those mid-20th century extensions that are misleadingly presented in the video as fundamental features of General Relativity.
The POE, in its current, extended usage, is mostly just a conjecture of mathematical convenience, allowing theorists to use Special Relativity math instead of the more difficult General Relativity formulations. It also results in a theoretical claim that the speed of light in a vacuum is a universal constant. That claim contradicts both GR which predicts that the speed of light varies with position in a gravitational field and observations which confirm that prediction.
This unwarranted belief that the speed of light is a universal constant has also produced a cottage industry of theorists expounding a theory of undetected structures called Black Holes with the physically absurd properties of an event horizon and a singularity. No such structures exist. The relativistic slowing of light in a gravitational field precludes their existence. It does not preclude the existence of massive high-density objects.
Ok, let’s grant that this video presentation is of dubious scientific quality and does not, perhaps, represent the consensus view of the scientific community, particularly with regard to the so-called Principle of Equivalence, although if not the consensus, the Strong POE certainly commands significant support by a majority of theoretical cosmologists . The usual suspects will whine, of course, that pop-science presentations like this video cannot be trusted.
That complaint is also lodged against anything written for a general audience, even when the author is a fully accredited scientist with a relevant FAS (full alphabet soup) after their name. If it’s written so non-experts can understand it, then it is, on some level, wrong.
The reason for this situation is straightforward: much of what theoretical physicists believe cannot be translated into clear, logical, statements of scientific fact. What you get instead is confident handwaving consisting of metaphysical assertions that have no factual basis in empirical reality and a lot of math. According to theorists this is because theoretical physics can only be properly understood by those steeped in years of study of the underlying mathematical esoterica that informs only the truly knowledgeable. To which the only proper retort is: math is not physics and if your math cannot be translated into empirically verifiable physical terms – then your math is inadequate to the task of being a proper scientific model of physical reality.
The modern POE is just a conjecture of mathematical convenience, nothing more. Nonetheless, this modern POE permeates and perverts the scientific literature. Here is an Encyclopedia of Britannica entry for the POE:
In the Newtonian form it asserts, in effect, that, within a windowless laboratory freely falling in a uniform gravitational field, experimenters would be unaware that the laboratory is in a state of nonuniform motion. All dynamical experiments yield the same results as obtained in an inertial state of uniform motion unaffected by gravity. This was confirmed to a high degree of precision by an experiment conducted by the Hungarian physicist Roland Eötvös. In Einstein’s version, the principle asserts that in free-fall the effect of gravity is totally abolished in all possible experiments and general relativity reduces to special relativity, as in the inertial state.
Britannica, The Editors of Encyclopaedia. “Equivalence principle”. Encyclopedia Britannica, 31 Mar. 2019, https://www.britannica.com/science/equivalence-principle. Accessed 6 June 2021.
It should be noted that, according to the encyclopedia’s referenced article on Roland Eötvös, his experiment “… resulted in proof that inertial mass and gravitational mass are equivalent…“, which is to say, that it demonstrated the Weak POE only. It is also clear, that the authors of this entry are confused about the distinctions between the three POEs. But what of that; it’s only an encyclopedia trying to make sense of the nonsensical world of the modern theoretical physicist and modern theoretical physics is an unscientific mess.
I have to give Ethan Siegel credit for having fully absorbed the catechism of orthodox cosmology in all its illogical, not to mention, unscientific, glory. Here, for example is a recent Forbes post entitled How Does The Fabric Of Spacetime Expand Faster Than The Speed Of Light? It provides a good illustration of Siegel’s inability to distinguish between the factual, and the unfounded theoretical aspects, of the standard model of cosmology. But then, that’s the nature of the orthodox belief system known, somewhat sarcastically, as the Big Bang.
For instance, the article mentions the maximum light speed in a vacuum but fails to note that the maximum can only be achieved in an inertial frame. Inertial frames are only approximated in physical reality. That little qualification completely unravels this bit of received wisdom:
But light didn’t work that way; it always moves at the same speed through the vacuum of empty space, from every perspective imaginable.
That, in fact, represents a rather monumental failure of the modern cosmological imagination, forsaking as it does, both Einstein’s understanding of Relativity Theory and the observational evidence. Not to mention the fact that there is no such thing as “empty space“. But then, facts are optional in the post-empirical realm of theoretical cosmology.
One of the great unforced errors of late 20th century theoretical physics was to declare the speed of light in a vacuum, a universal constant. This was done despite the fact that, according to General Relativity, the speed of light varies with position in a gravitational field. This variation in light speed has been observed.
The idea that the speed of light varies with position in a gravitational field is not new. It comes on good authority:
…according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity and to which we have already frequently referred, cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position. Now we might think that as a consequence of this, the special theory of relativity and with it the whole theory of relativity would be laid in the dust. But in reality this is not the case. We can only conclude that the special theory of relativity cannot claim an unlimited domain of validity: its results hold only so long as we are able to disregard the influences of gravitational fields on the phenomena (e.g. of light).
Albert Einstein, Relativity The Special And The General Theory, 15th edition
The claim of those who wish to maintain the universal constancy of light speed (c) is that it is justified by the Equivalence Principle. The rather lengthy linked discussion goes into some detail but no mention is made of the constancy of c being consequent on the EP. None of the tests of the principle cited in the article involve measuring the value of c directly.
Einstein invoked the EP in the derivation of General Relativity to provide an interpretation of the observed fact that inertial mass and gravitational mass are equivalent. Given the above quote, he obviously did not find justification therein for asserting the universal constancy of c.
The only reasonable conclusion is that the EP does not justify the claim of a universally constant light speed. The claim appears to be only a lazy mathematicist assumption of mathematical convenience. Theoretical physics is a remarkably irrational, unscientific mess because of this sort of nonsense.
