Commentary on Interview of Ezra Newman regarding
Einstein's ground-breaking theory
Roger J Anderton
[email protected]
I provide my comments on the answers that physicist Ezra Newman
gave on Einstein's relativity. People who know me will probably
know by now that I will mention Boscovich a lot, but by contrast
Ezra Newman will not make any mention of him.
In article “It's all relative: Ezra Newman on Einstein's ground-breaking theory,” [1]
Ezra Newman is described as professor emeritus at the University of Pittsburgh.
Newman who was a prominent contributor to the golden age of general relativity
(roughly 1960-1975).
Let's look at some of the answers to questions he was asked:
Q: You're principally known for your work in the area of general relativity. Can you
begin by telling us what general relativity is?
Newman: There is both a short, correct and easy answer, which leaves out the essence
of a good answer, and a longer, more difficult answer that does get to the core of what
the theory is about.
Newman: At the simple level, one could say that general relativity is a theory of
gravity that supersedes Newton's Theory of gravity and that it makes slightly more
accurate predictions than Newton's theory did.
Me: “supersedes” - In terms of mathematical models – treating Newton's theory as a
maths model then general relativity is a maths model update.
Newman: It [general relativity] is a correct answer and does give some hint of the
subject.
Me: That is a big oversimplification bearing in mind the theorists around Wheeler
school have made changes.
[See my article “Relativity revival reinstates Newtonian physics”. ]
Newman: At the deeper level, general relativity is a revolution of physical thought. It
is about the geometry of our world. [*]
Me: [*] he means “universe” not “world”, sometimes the word “world” has been used
that way by physicists.
Newman: Something like 22 centuries ago, Euclid organized the available knowledge
into a book called Elements. For 20 centuries, it was believed that it was both the
geometry of our world and, in addition, that it was the only possible geometry.
Immanuel Kant said, in essence, that. "God geometrizes according to Euclid's
'Elements'." Then, in the early 1800s, with the intellectual awakening throughout
Europe happening virtually simultaneously and independently, three mathematicians Gauss in Germany, Bolyai in Hungary and Lobachevski in Russia - realized that other
geometries did exist.
Me: He misses out saying that these people probably got the idea from Boscovich's
theory. Boscovich's theory seems to be the first physical theory to deal with nonEuclidean geometry.
[see for instance: “300th birthday of Ruđer Josip Bošković (Roger Joseph
Boscovich)” by Franka Miriam Brueckler, http://www.mathematics-ineurope.eu/index.php?option=com_content&view=article&id=678&lang=de quote:
“his [Boscovich's] claim that the Euclid's Fifth Postulate (about parallels) cannot be
proved from the other Euclidean axioms, make him a forerunner of the discovery of
non-Euclidean geometries.” ]
Newman: It seems as if Gauss and his student Riemann were among the first to raise
the question of what was the geometry of our world.
Me: Misses out Boscovich again.
Newman: A variety of scientists, among them the great Hermann von Helmholtz, tried
to tackle this issue. The mathematician Hermann Minkowski, in his fundamental work
on Einstein's special Theory of Relativity, came close to realizing the proper
framework for exploring the issue of the geometry of our world - but he died
prematurely before doing anything more. It was Einstein, who, after struggling almost
10 years with the problem, finally developed the General Theory of Relativity - the
theory of the geometry of our world.
Me: There are priority disputes with whether Einstein really was first, but let's pass on
that.
Newman: This geometry was not a fixed geometry, as was Euclid's, but varied
depending on the matter content of the surrounding space.
Me: OK and that geometry is a convention and can be mapped to other geometries.
(i.e. I am pointing out something that was missed from being said.)
Newman: As a by-product, though that was the issue that provoked his investigation,
the theory did produce an explanation of the phenomena of gravity; gravitational
forces were the manifestations of the curvature of space and time. In addition, the
theory produced a picture of the universe in the large, i.e., it opened the subject of
cosmology to rigorous scientific investigation.
Me: OK, and that geometry of gravitational forces represented by space-time
curvature can be mapped to an Euclidean geometry of Newtonian physics with its
gravitational forces.
Q: Ever since Einstein revealed his theory of general relativity in 1915, it has had a
remarkable run as the most widely accepted theory of gravitation. Although Einstein
was certain that his theoretical principles were correct, he proposed a few
experimental tests to confirm his predictions. Can you briefly describe these tests?
Newman: There were three classical tests of general relativity.
Newman: 1. According to Newton's theory of gravity, planets moved around the sun
in orbits that are ellipses. The point on the ellipse that is closest to the sun is referred
to as the perihelion.
Newman: It had been observed by astronomers in the mid-1800s that the perihelion of
the planet Mercury was not fixed (as it should be by Newton's theory) but moved
forward, i.e., it advanced with each circuit of the sun - albeit by a very small amount.
Me: And in the context of the maths model of Newtonian physics would treat that as
an extra effect that could be added by maths model update.
Newman: There was thus a disparity between observation and theory. Einstein's
theory predicted this small effect, known as the advance of the perihelion of Mercury.
The measured perihelion advance agreed with the theory.
Me: There are claims that Einstein bodged it, but pass on that.
Newman: 2. In the early 1800s, it was shown, via Newton's theory, that the
gravitational effects of the sun would bend star-light that passed close to the limb of
the sun. Einstein's theory also made the same prediction but it differed by predicting
that the effect would be twice as much as that of Newton's theory.
Me: So in the maths model of Newtonian physics that was used at that time, it would
mean updating the maths model by doubling the force.
Newman: In 1919, in several expeditions, all timed to coincide with a solar eclipse
(needed to block out the direct solar sunlight), this prediction was confirmed (with
questions raised of its accuracy).
Me: There were “questions raised of its accuracy” because it looked like Eddington
bodged the experiment/observation.
Newman: Since then, it has been reconfirmed with extreme accuracy. This particular
confirmation made Einstein a household name. The New York Times carried the story
on the front page.
Me: The thing to note here is – Einstein became a household name – famous- before
his prediction was properly confirmed, because it wasn't confirmed in 1919 with the
Eddington observation.
Newman: 3. The third of the classical tests concerned a prediction of general
relativity that time would evolve at different rates in regions of strong gravitational
fields.
Me: Time measurements are also affected by gravitational fields in context of
Newton's theory.
Newman: This is a difficult effect to directly measure but a simple indirect test was
available. The colour of the light emitted by atoms in a strong gravitational field
would be different from that of the light from the same type of atoms in a weaker
gravitational field. This was first observed by a shift in the spectral lines (the specific
colours emitted) from the dwarf star Sirius B, becoming the so-called «gravitational
red shift» effect. It has since been reconfirmed by very accurate laboratory
experiments.
Me: Its peculiar to equate frequency of light with time measurements, frequency f =
1/T where T = period, if frequency and period of a wave of light changes does it really
affect time measurement of device measuring f and T; if it did then surely wouldn't
then see no change in f and T if time measuring device changed in step with them.
(However, its an issue I will have to reconsider more at some later date.)
Q: With the advancement of technology, our tools have become better at measuring
and predicting with greater accuracy. What modern day tests has general relativity
recently faced?
Newman: There are a variety of modern tests; they range from great technical
improvements in the classical tests to the development of a major astronomical tool
for exploring the universe in the large. Some of the classical solar system tests have
been implemented for the dynamics of double star systems, the binary pulsar for
example. This later case actually has been used to confirm the existence of
gravitational radiation via the change in the pulsar orbital parameters that is predicted
by the theory.
Newman: The classical test of the bending of light near the sun has been extended to
the bending of light near other astronomical bodies and in fact is no longer considered
as a test. It has become a tool itself to study astronomical parameters, as for example
it is used to measure the mass of astronomical objects.
Me: That's peculiar - “no longer considered as a test” - sounds like an admission that
is not a test of any difference between Newton's theory and general relativity. After
the fiasco of 1919 observation – it sounds like they have settled down and decided it
wasn't a test of any difference with what Newton's theory could handle.
[See once again- my article “Relativity revival reinstates Newtonian physics”.]
Newman: Another very large and important subject, not yet completed, is the
construction of detectors to measure gravitational radiation. They involve huge
government instillations costing millions of dollars - and again they will not be used
primarily for testing the theory but rather as a new window for observing our
universe. The theory itself has essentially gone into the mainstream and is now being
used as another probe in the same way light-waves are used to gather information.
Me: The words here- “not be used primarily for testing the theory” - suggestive once
again it is not testing a difference with Newton.
Newman: The default picture of the universe with its big bang and Hubble-expansion
has been a prediction from the theory of relativity. Observations and existence of the
Cosmic Microwave background are thus further confirmations. The theory, with the
associated observations, is a tool for understanding the details of the big bang
cosmology.
Me: “default picture” - just something they want to set observations to fit that
“picture.”
Q: Einstein was often confounded by ideas that other researchers derived from his
theories which, in some cases, led him to revise his work.
Me: yeah “revise”, which leads to issue of what revision is supposed to be Einstein's
relativity; an issue that the mainstream does not want to rigorous explain as to what
precisely has been revised. Question continues:
Q: In one particular case, Einstein introduced what he called a cosmological constant
to fix what appeared to be a flaw in general relativity. Can you describe the
circumstances surrounding this problem?
Newman: Early in the history of general relativity, Einstein understood that the theory
could be applied to the large scale structure of the universe, i.e., to cosmology.
However, he could not construct a static universe (which was believed at the time to
be the type of our universe) from the theory. He modified the theory by adding into
the equations a new term known as the cosmological constant. Shortly after that, it
was discovered that our universe was not static but was in fact expanding, and the
cosmological constant was not needed. Einstein called the addition of the
cosmological constant to be "the biggest blunder of his life" He dropped it from the
theory.
Me: yeah, just adjust the theory to whatever is believed, can be called bodging.
Newman: More recent observations of the distance relations with supernova and the
cosmological red shift has strongly indicated that the universe is not only expanding
but also is accelerating. This observational result is now most simply explained by the
existence of the cosmological constant. The cosmological constant has thus been
added to the standard model of cosmology.
Me: yeah adjust the theory again to whatever is believed
Q: The incompatibility of Newtonian gravity and special relativity led Einstein to
General Relativity. In what ways is General Relativity being reconciled with quantum
mechanics?
Newman: Though there is debate and disagreement,
Me: yeah- “debate and disagreement,” particularly I think because question issued to
Newman was making claims that are false. Just a bit of maths manipulation and I can
get Newtonian gravity to fit with special relativity.
[several of my papers are on this.]
Newman: I certainly do not believe that general relativity and quantum theory have
been reconciled (or are even close to being reconciled) - my feeling (without having
taken a survey) is that most physicists who are concerned about this issue would agree
with me.
Me: yeah, because mainstream physics is messed up.
Newman: But to be fair and honest about the question, one must say that there
certainly are excellent researchers who do believe that they are close to this
reconciliation.
Me: yeah – Boscovich's theory, before Einstein made the mess.
Newman: In any case, I do consider this problem, i.e., the problem of uniting the two
most important and remarkable contemporary physical theories into a single unified
theory, to be the single most important conceptual issue in physics today. It is a
problem that theorists have been struggling with for close to 90 years. And it is
difficult. One of the principle difficulties is with quantum theory - a magnificent
theory - that to many makes no sense.
Me: yeah “no sense” because a lot of nonsense is said in the mess that Einstein seems
to have initiated.
Q: For a time, general relativity fell out of favour as a respectable field of inquiry
because of its remoteness from laboratory experiment. Can you tell us how and when
it regained its legitimacy?
Newman: This is a very interesting question - without any simple, quick answer.
Some of my answer is guesswork...while other parts are easily defended.
Newman: From the beginning of general relativity in 1915, because of its
mathematical complexity and the scarcity of experimental tests, it did not really enter
into the mainstream of physics. For a while, it did remain an active research field for a
small group of mathematicians and mathematical physicists. In the mid and late
1920s, the discovery and development of quantum theory did draw much of the
interest away from relativity. The predictive power of Quantum Theory and its direct
contact with laboratory physics kept it at the very top of mainstream physics - and
monopolized the talents of the best of the theoreticians. After the war, (the early to
mid-1950s), there was a sudden worldwide explosion of reawakened interest in
general relativity. A group in Warsaw working with an old colleague of Einstein's,
Leopold Infeld, began working; while in Hamburg, the group around Pascal Jordan
developed; in Princeton, the group around John Wheeler (already well-known for his
work in nuclear physics) turned to relativity; at Syracuse University, Peter Bergmann,
a former student of Einstein's, began a relativity group; in London, Hermann Bondi
started a relativity group. Precisely what it was that provoked this international
renaissance, is, at least for me, conjecture.
Me: This “renaissance” was when general relativity was revised, see again my article
- “Relativity revival reinstates Newtonian physics”
Newman: Most of the main problems of quantum theory had been dealt with - while
its very serious difficulties sent people looking elsewhere for problems and solutions.
The war years were over - a freedom to look for new issues was in the air - friends,
students and colleagues of Einstein's were now available, after war work, to think of
the issues and ideas raised by Einstein and his work. In any case, it was fascinating for
me to watch and live through this period - this leap of scientific interest in general
relativity.
Me: Yeah and Wheeler's group point out Boscovich's theory is unified field theory.
[ Which is topic of my next lecture for NPA.]
Me: Pass on talk about gravitational radiation detectors, and some stuff on Wheeler's
school.
Q: Are there any intractable problems posed by general relativity that have not yet
been answered?
Newman: As we discussed earlier, it appears to me that the issue of the relationship
between general relativity and quantum theory is still the most intractable and basic
issue in theoretical physics.
Me: Unification of quantum physics and relativity is of course dealt with by unified
field theory of Boscovich.
Newman: Other troubling issues are the questions raised by the existence of the socalled dark energy and dark matter- what precisely are they?
Me: Newtonian gravitational force varies only as inverse square law only for limited
range as per Boscovich.
Newman: Another intractable problem has been the origin of the 'big bang' - what was
there 'before?' What, if any, is its relationship to the issues of quantum theory?
Me: Multi-universe as per Boscovich's theory.
Pass on his future research plans.
Conclusion
Einstein's relativity is now a vast subject in academia, with a great many papers being
written on both theory, experiments etc.; so although Ezra Newman -is an expert on
the subject, he does not seem to know the full history of the subject, specifically he
does not seem to know about Boscovich. So although Boscovich is part of the history
of physics of Wheeler's school on Einstein's relativity, Ezra Newman does not seem to
be aware of it. Hence when it comes to issues dealing with unified field theory he
does not mention Boscovich; its an obscure fact in Wheeler's school and it has not
been told him.
Reference
[1] It's All Relative: Ezra Newman On Einstein's Ground-breaking Theory
http://simplycharly.squarespace.com/ezra-newman-on-einstein/
c.RJAndertonOct2012