Scientific American, EINSTEIN DIDN'T SAY THAT!

In the September "Einstein" issue of Scientific American, audiences are given the impression that gravity is caused by curvature of space-time. For instance, on the 1st page of that segment, we read "gravity ... is the by-product of a curving universe", on p. 43 we discover that "the Einstein tensor G describes how the geometry of space-time is warped and curved by massive objects", and on p. 56 there is a reference to "Albert Einstein's explanation of how gravity emerges from the bending of space and time".

In reality, many physicist today emphasize "curvature" as the definition for gravity. As Stephen Hawking penned in A Brief History of Time, "Einstein made the revolutionary suggestion that gravity is not a force like other forces, but is a consequence of the fact that space-time is not flat, as had been previously assumed: it is curved, or warped.".

The issue is, that's NOT what Einstein said. Einstein made it rather clear that gravity is a force like other forces, along with (obviously) specific distinctions. In the actual paper cited by Scientific American ("The foundation of the general theory of relativity", 1916) he wrote," [there is] a field of force, namely the gravitational field, which possesses the remarkable property of imparting the same acceleration to all bodies". The G tensor, said Einstein "describes the gravitational field." The term "gravitational field" or just "field" occurs 58 times in this article, while the word "curvature" doesn't turn up at all (except in relation to "curvature of a ray of light"). And Einstein is not the only physicist who believes that. For example Sean Carroll, a prominent physicist of today, wrote:.

Einstein's general relativity describes gravity in terms of a field that is defined at every point in space ... The world is really made out of fields ... deep down it's really fields ... The fields themselves aren't "made of" anything-- fields are what the world is made of ... Einstein's ... "metric tensor"... can be thought of as a collection of ten independent numbers at every point.-- Sean Carroll.

To suppress the field concept and emphasize "curvature" not only misstates Einstein's perspective; it likewise offers folks a false or deceptive understanding of basic relativity.

So where does "curvature" originated from? According to Einstein (in the cited paper), the gravitational field causes physical adjustments in the length of measuring rods (just like temperature can cause such changes) and it is these changes that produce a non-Euclidean metric of space. Actually, as Einstein indicated, these changes can take place even in a space which is without gravitational fields-- i.e., a rotating system. He then showed that this non-Euclidean geometry is mathematically equal to the geometry on a curved surface, which had been developed by Gauss and extended (mathematically) to any number of dimensions by Riemann. That this is a mathematical equivalence is clearly stated by Einstein in a later paper: "mathematicians long ago solved the formal problems to which we are led by the general postulate of relativity".

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Book Clarifies Confusing Quantum Field Theory

The following is a current article written about Quantum Field Theory and the book, Fields of Color. The write-up appeared in the Leisure World News on September 4, 2015.

The publication "Fields of Color: The Theory that Escaped Einstein" clarifies the perplexing Quantum Field Theory in order that a layman can understand it. Written by Leisure World resident Rodney Brooks, it features no equations-- in fact, no math-- and it makes use of colors to represent fields, which in themselves are difficult to picture. It demonstrates the field picture of nature resolves the paradoxes of quantum mechanics and relativity that have puzzled so many people. It is original, comprehensive, and entertaining.

Brooks is blown away and pleased with the success of his book, which was released in 2011. He says 6,000 copies have been sold, rare for a self-published book on physics. On top of that, the publication has a 4.4 (out of 5) star rating on Amazon along with greater than 90 reader reviews-- a higher score than Einstein's own book on relativity and above Stephen Hawking's popular book "The Theory of Everything.".

In its essence, quantum field theory (QFT) illustrates a world comprised of fields, not particles (neutrons, electrons, protons) as most physicists believe. Nevertheless the field principle is difficult to grasp. To quote from Chapter 1 of "Fields of Color": "To put it briefly, a field is a property or a condition of space. The field concept was introduced into physics in 1845 by Michael Faraday as an explanation for electric and magnetic forces. However, the idea that fields can exist by themselves as "properties of space" was too much for physicists of the time to accept." (Chapter 1 in its entirety can be read at http://www.quantum-field-theory.net/).

Colors of Fields.
Later on this principle was expanded to other fields. "In Quantum Field Theory the entire fabric of the cosmos is made of fields, and I use (arbitrary) colors to help people visualize them," says Brooks. "If you can picture the sky as blue, you can picture the fields that exist in space. Besides the EM (electromagnetic) field ('green'), there are the strong force field ('purple') that holds protons and neutrons together in the atomic nucleus and the weak force field ('brown') that is responsible for radioactive decay. Gravity is also a field ('blue'), and not 'curvature of space-time' which most people, including me, have trouble visualizing.".

He carries on: "In QFT, space is the same old three-dimensional space that we intuitively believe in, and time is the time that we intuitively believe in. Even matter is made of fields-- in fact two fields. I use yellow for light particles like the electron and red for heavy particles,.

like the proton. But make no mistake, in QFT these 'particles' are not little balls; they are spread-out chunks of field, called quanta. Thus the usual picture of the atom with electrons traveling around the nucleus like little balls, is replaced by a 'yellowness' of the space around the nucleus that represents the electron field.".

Brooks' interest in physics was first kindled when at age 14 he read Arthur Eddington's "The Nature of the Physical World." This publication describes how a table is made of little atoms that consequently can be divided into even tinier objects. "So this is what the world is built of," Brooks thought back then. In college at the University of Florida he majored in math with a minor in physics. He was then drafted into the army for two years.

Quantum Field Theory Answers Problem.
Fast forward to graduate school at Harvard University where Brooks was a National Science Foundation scholar, majoring in physics. During the course of this time, he enrolled in a three-year formal lecture series instructed by Julian Schwinger. The Nobel prize-winning physicist had just completed his reformulation of QFT, so the timing was perfect. "I was surprised that all the paradoxes of relativity and quantum mechanics that had previously perplexed me evaporated or were resolved," Brooks says.

After acquiring his Ph.D. at Harvard under Nobel laureate Norman Ramsey, Brooks worked for 25 years at the National Institutes of Health in Bethesda, Md., in neuroimaging. His first research study was regarding the brand new procedure of Computered Tomography (CT), during which time he devised the approach now known as dual-energy CT. Later, he did research on Positron Emission Tomography (PET) and ultimately in Magnetic Resonance Imaging (MRI). All in all, Brooks published 124 peer-reviewed articles.

Once he retired, he and his wife, Karen Brooks, relocated to New Zealand in 2001. That was when he became aware of the prevalent confusion about physics, specifically quantum mechanics and relativity, whilst his cherished QFT that fixes the confusion was disregarded, misunderstood, or neglected.

"Consequently I undertook the mission of illustrating the concepts of quantum field theory to the public," Brooks says.

His book was initially published in New Zealand in 2010, and is presently in its second edition.

In 2012, his grandchildren, who reside in Maryland called out, and he and his wife relocated to Leisure World, where he moves ahead to work on his purpose. Whilst Einstein ultimately came to think that reality must contain fields and fields alone, he preferred there to be a solitary "unified" field that would not merely consist of gravity and electromagnetic forces (the only two forces recognized back then), but would additionally contain matter.

He invested the last 25 years of his life unsuccessfully looking for this unified field theory.

Referring to the particle picture that he espoused, physicist Richard Feynman once said, "The theory ... describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you can accept Nature as She is-- absurd.".

Brooks, alternatively, concludes his initial chapter by saying, "I hope you can accept Nature as She is: beautiful, consistent and in accord with common sense-- and made of quantized fields.".

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Space-Time Curvature & Quantum Field Theory

General Relativity is the name provided for Einstein's theory of gravity that was defined in Chapter 2 of my book. As the idea is usually shown, it explains gravity as a curvature in four-dimensional space-time. Now it is a concept far over and above the reach of common people. Just the concept of four-dimensional space-time causes the majority of us to shudder ... The answer in Quantum Field Theory is easy: Space is space and time is time, and there is no curvature. In QFT gravity is a quantum field in ordinary three-dimensional space, just like the other 3 force fields (EM, strong and weak).

This does not actually suggest that four-dimensional notation is not useful. It is a convenient way of handling the mathematical connection between space and time which is needed by special relativity. One could almost say that physicists couldn't live without having it. Still, spatial and temporal evolution are fundamentally different, and I say shame on people who aim to foist and push the four-dimensional concept onto the general public as vital to the understanding of theory of relativity.

The idea of space-time curvature likewise had its origin in mathematics. When seeking a mathematical approach that could embody his Principle of Equivalence, Einstein was led to the formulas of Riemannian geometry. And indeed, these formulas define four-dimensional curvature, for individuals who are able to imagine it. You see, mathematicians are not confined by physical constraints; equations that have a physical definition in 3 dimensions can possibly be generalized algebraically to any variety of dimensions. But when you do this, you are truly handling algebra (equations), not geometry (spatial configurations).

By expanding our minds, several of us are able to even make a faint mental image of what four-dimensional curvature might be like if it did exist. Nevertheless, claiming that the gravitational field equations are equal to curvature is definitely not the same as stating that there is curvature. In Quantum Field Theory, the gravitational field is just another force field, like the EM, strong and weak fields, though with a higher complication which is demonstrated in its higher spin value of 2.

While QFT resolves these paradoxical declarations, I really don't wish to leave you having the thought that the theory of quantum gravity is problem-free. While computational issues concerning the EM field were overcome with process referred to as renormalization, comparable challenges involving the quantum gravitational field have not been conquered. Fortunately they do not interfere with macroscopic computations, for which the QFT formulas become the same to Einstein's.

Your choice. Once again you the reader have an option, as you did in concern to the two methods to special relativity. The option is not about the formulas, it has to do with their perception. Einstein's equations can be deciphered as suggesting a curvature of space-time, unpicturable as it may be, or as detailing a quantum field in three-dimensional space, just like the other quantum force fields. To the physicist, it actually doesn't make much difference. Physicists are far more concerned with solving their formulas rather than with analyzing them. If you will permit me another Weinberg quote:

The important thing is to be able to make predictions about images on the astronomers photographic plates, frequencies of spectral lines, and so on, and it simply doesn't matter whether we ascribe these predictions to the physical effects of gravitational fields on the motion of planets and photons or to a curvature of space and time. (The reader should be warned that these views are heterodox and would meet with objections from many general relativists.)-- Steven Weinberg

Therefore in case you prefer, you can believe that gravitational effects are due to a curvature of space-time (despite the fact that you can't visualize it). Or, like Weinberg (and me), you can view gravity as a force field that, similar to the other force fields in Quantum Field Theory, exists in three-dimensional space and progresses in time according to the field equations.

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