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From: michaelm@3comvax.UUCP (Michael McNeil)
Newsgroups: net.physics
Subject: Bogus physics reamplified
Message-ID: <446@3comvax.UUCP>
Date: Tue, 11-Mar-86 21:13:23 EST
Article-I.D.: 3comvax.446
Posted: Tue Mar 11 21:13:23 1986
Date-Received: Fri, 14-Mar-86 04:49:16 EST
References: <368@ihnet.UUCP> <2057@jhunix.UUCP> <2874@sjuvax.UUCP>
Reply-To: michaelm@3comvax.UUCP (Michael McNeil)
Distribution: net
Organization: 3Com Corp; Mountain View, CA
Lines: 291
Keywords: general relativity, justifying assertions, name-calling
Summary: Please, people, learn more about relativity!

In article <2874@sjuvax.UUCP> bhuber@sjuvax.UUCP (B. Huber) writes:
>In article <2057@jhunix.UUCP> ins_adsf@jhunix.UUCP writes:
>>In article <368@ihnet.UUCP> eklhad@ihnet.UUCP (K. A. Dahlke) writes:

>>>> 1) According to Einstein, it's relative--there _is_no_such_thing_ as
>>>> absolute rest.  You _can_ say that the sun goes around the earth;
>>>> the math is just easier the other way.
>>>>			Kenneth Arromdee

>>>Oh come on folks!!!  The sun (universe) does not twirl around the earth!!!
>>>Einstein never even implied such a thing.
>>>Motion is relative *only* when considering inertial reference frames,
>>>as determined by Lawrence transformations.
>>>Rotation is definitely not an inertial reference frame.
>>>It is not a matter of mathematical complexity,
>>>the earth really does rotate.
>>>Put simplistically (as we must when posting to this newsgroup),
>>>if the universe spun around the earth, it would fly apart,
>>>and even nearby galaxies would be traveling faster than light.
>>>Similarly, the earth revolves around the sun,
>>>and the solar system revolves within our galaxy.
>>>These are not arbitrary conventions, they are facts.
>>>The amount of bogus physics in this newsgroup is astonishing.
>>>			Karl Dahlke

>>    I don't intend to get involved in the evolution argument, but if the 
>>universe would fly apart when rotating about the earth, it will just as
>>surely disintegrate when rotating about the sun.  So that reasoning falls
>>apart.  Nothing really rotates strictly about anything. 
>>    It is correct that Einstein spoke about inertial reference frames, but
>>a note to Mr. Dahlke:  name calling begins at home.  Refering to Lorentz
>>transformations as "Lawrence transformations" shows that your knowledge
>>in this field is also "bogus".
>>			David Fry

>What reasoning falls apart?  I fail to comprehend the (apparently)
>extraordinary leap of logic that is required to reason from the specific 
>proposition, 'the universe does not rotate around the sun' to the general
>proposition, 'nothing ... rotates ... about anything'.  Fry owes us, at
>least, an elaboration of this argument. 
>
>I cannot see either that misspelling 'Lorentz' nullifies any of Dahlke's
>argument, which should be judged on its own merits.  {...}
>
>As to name-calling, I read none of that in Dahlke's article.  It is only
>natural that someone who is even modestly acquainted with modern physics
>would become upset at the plethora of unsupported assertions that appear
>in this newsgroup.  There is nothing the matter, per se, with being wrong:
>having the opportunity to make mistakes is what learning and investigation
>are all about.  Making an assertion without any support is to maintain
>a position solely on one's personal authority.  Such a stance is rarely
>illuminating.  
>			Bill Huber

Come on, people!  It isn't just the misspelling, it isn't just the
strong language (whether you call it name-calling or not) -- Karl's
argument is completely wrong!  Einstein's theory of general relativity
was published more than seventy years ago (1915) -- and it certainly
*does* allow non-inertial reference frames!  Only Einstein's *special*
relativity (1905) is restricted in its application to inertial frames.  

It's a shame knowledge of Einstein's theory isn't more widespread
(especially in net.physics!) so many years after it was published.  
Though, I suppose, like they say of churches, net.physics isn't a
temple for saints, but a hospital for sinners.  I imagine it must
be the memories of all those undergraduate physics classes, where
inertial reference frames were ground into our flesh, never to be
forgotten, while terms like "special" (applied to what one knew) and
"general" (applied to what one did not know) gradually slip away.  
I *highly* recommend that people learn *more* about relativity!  

An excellent up-to-date reference for those with a modicum of college-
level physics background is *Gravitation*, by Charles W. Misner, Kip S.
Thorne, and John Archibald Wheeler, published in 1973 by W. H. Freeman
and Co., San Francisco.  This 1,310-page tome declares itself to be
"a textbook on gravitation physics (Einstein's `general relativity'
or `geometrodynamics')."  The book is designed to provide a full-year,
rigorous, graduate-level course in gravitation physics -- intending,
as it says, "to give a competence in gravitation physics comparable to
that which the average Ph.D. {in physics} has in electromagnetism."  

There is also an alternative route through the text ("Track 1") which
is less thorough.  "It is suitable for a one-semester course at the
junior or senior level or in graduate school; and it constitutes --
in the opinion of the authors -- the indispensable core of gravitation
theory that every advanced student of physics should learn."  
Mathematical prerequisites for Track 1 are "only vector analysis and
simple partial-differential equations."  I highly recommend the book.  

Additional references in relativity theory and gravitation physics:  

	Albert Einstein, *The Meaning of Relativity*, Fifth Edition,
	Princeton University Press, Princeton, 1956.  A mathematical
	introduction to both the special and general theories.  

	Albert Einstein, *Relativity: The Special and General Theory*,
	Crown Publishers, Inc., New York, 1961.  An elementary
	exposition of the relativity theories; only algebra is needed.

	Bertrand Russell, *The ABC of Relativity*, Revised Edition,
	George Allen and Unwin, Ltd., or Signet Science Library, 1958.  
	Another elementary introduction -- but no algebra is required.  

Returning to Ken's original point, which started off this whole series
of articles, in the above reference Bertrand Russell writes as follows:  

	But in the modern theory the question between Copernicus and
	his predecessors is merely one of convenience; all motion
	is relative, and there is no difference between the two
	statements:  `the earth rotates once a day' and `the heavens
	revolve about the earth once a day.'  The two mean exactly the
	same thing, just as it means the same thing if I say a certain
	length is six feet or two yards.  Astronomy is easier if we
	take the sun as fixed than if we take the earth, just as
	accounts are easier in decimal coinage.  {Signet, pp. 13-14}

I would think this would finish the debate over what Einstein "never
even implied."  However, it is still relevant to ask, what is the
status of Einstein's theory of general relativity in modern physics?  
The following two sections from Misner, Thorne, and Wheeler's
*Gravitation* explore this question of alternative theories of gravity.  

	39.1.  Other Theories

	Among all bodies of physical law none has ever been found that
	is simpler or more beautiful than Einstein's geometric theory
	of gravity {...}; nor has any theory of gravity ever been
	discovered that is more compelling.  

	As experiment after experiment has been performed, and one
	theory of gravity after another has fallen by the wayside a
	victim of the observations, Einstein's theory has stood firm.  
	No purported inconsistency between experiment and Einstein's
	laws of gravity has ever surmounted the test of time.  

	*Query*:  Why then bother to examine alternative theories
	of gravity?  *Reply*:  To have "foils" against which to
	test Einstein's theory.  

	To say that Einstein's geometrodynamics is "battle-tested"
	is to say it has won every time it has been tried against a
	theory which makes a different prediction.  How then does one
	select new antagonists for decisive new trials by combat?  

	Not all theories of gravity are created equal.  Very few,
	among the multitude in the literature, are sufficiently
	viable to be worth comparison with general relativity or with
	future experiments.  The "worthy" theories are those which
	satisfy *three criteria for viability: self-consistency,
	completeness, and agreement with past experiment*.  

	*Self-consistency* is best illustrated by describing several
	theories that fail this test.  The classic example of an
	internally inconsistent theory is the spin-two field theory
	of gravity [Fierz and Pauli (1939) {...}], which is equivalent
	to linearized general relativity {...}.  The field equations
	of the spin-two theory imply that all gravitating bodies move
	along straight lines in global Lorentz reference frames,
	whereas the equations of motion of the theory insist that
	gravity deflects bodies away from straight-line motion.  
	(When one tries to remedy this inconsistency, one finds
	oneself being "bootstrapped" up to general relativity {...}.)  
	Another self-inconsistent theory is that of Kustaanheimo
	(1966).  It predicts zero gravitational redshift when the
	wave version of light (Maxwell theory) is used, and nonzero
	redshift when the particle version (photon) is used.  

	*Completeness*:  To be complete a theory of gravity must be
	capable of analyzing from "first principles" the outcome of
	every experiment of interest.  It must therefore mesh with
	and incorporate a consistent set of laws for electromagnetism,
	quantum mechanics, and all other physics.  No theory is
	complete if it *postulates* that atomic clocks measure the
	"interval" dTau {...} constructed from a particular metric.  
	Atomic clocks are complex systems whose behavior must be
	calculated from fundamental laws of quantum theory and
	electromagnetism.  No theory is complete if is *postulates*
	that planets move on geodesics.  Planets are complex systems
	whose motion must be calculated from fundamental laws for
	the response of stressed matter to gravity.  {...}

	*Agreement with past experiment*:  The necessity that a theory
	agree, to within several standard deviations, with the "four
	standard tests" (gravitational redshift, perihelion shift,
	electromagnetic-wave deflection, and radar time-delay) is
	obvious.  Equally obvious but often forgotten is the need to
	agree with the expansion of the universe (historically the ace
	among all aces of general relativity) and with observations at
	the more everyday, Newtonian level.  Example:  Birkhoff's
	(1943) theory predicts the same redshift, perihelion shift,
	deflection, and time-delay as general relativity.  But it
	requires that the pressure inside gravitating bodies equal the
	total density of mass-energy, p = rho; and, as a consequence,
	it demands that sound waves travel with the speed of light.  
	Of course, this prediction disagrees violently with experiment.  
	Therefore, Birkhoff's theory is not viable.  Another example:  
	Whitehead's (1922) theory of gravity was long considered a
	viable alternative to Einstein's theory, because it makes
	exactly the same prediction as Einstein for the "four standard
	tests."  Not until the work of Will (1971b) was it discovered
	that Whitehead's theory predicts a time-dependence for the
	ebb and flow of ocean tides that is completely contradicted
	by everyday experience {...}.  

	39.2.  Metric Theories of Gravity

	Two lines of argument narrow attention to a restricted class
	of gravitation theories, called *metric theories*.  

	The first line of argument constitutes the theme of the
	preceding chapter {i.e. Chapter 38 -- "Testing the Foundations
	of Relativity"}.  It examined experiment after experiment, and
	reached two conclusions:  (1) *spacetime possesses a metric;
	and* (2) *that metric satisfies the equivalence principle*
	(the standard special relativistic laws of physics are valid
	in each local Lorentz frame).  *Theories of gravity that
	incorporate these two principles are called metric theories*.  
	In brief, Chapter 38 says, "For any adequate description of
	gravity, look to a metric theory."  *Exception*:  Cartan's
	(1922b, 1923) theory ["general relativity plus torsion"; see
	Trautman (1972)] is nonmetric, but agrees with experiment and
	is experimentally indistinguishable from general relativity
	with the technology of the 1970's.  

	The second line of argument pointing to metric theories begins
	with the issue of completeness (preceding section).  To be
	complete, a theory must incorporate a self-consistent version
	of all the nongravitational laws of physics.  No one has found
	a way to incorporate the rest of physics with ease except
	to introduce a metric, and then invoke the principle of
	equivalence.  Other approaches lead to dismaying complexity,
	and usually to failure of the theory on one of the three
	counts of self-consistency, completeness, and agreement with
	past experiment.  *All the theories known to be viable in 1973
	are metric*, except Cartan's.  [See Ni (1972b); Will (1972).]  

	In only one significant way do metric theories of gravity
	differ from each other: their laws for the generation of the
	metric.  In general relativity theory, the metric is generated
	directly by the stress-energy of matter and of nongravitational
	fields.  In Dicke-Brans-Jordan theory {...} {Brans and Dicke
	(1961); Jordan (1959); Dicke (1962)}, matter and nongravita-
	tional fields generate a scalar field phi; then phi acts
	together with the matter and other fields to generate the
	metric.  Expressed in the language of section 38.7, phi is
	a "new long-range field" that couples indirectly to matter.  
	As another example, a theory devised by Ni (1970, 1972) {...}
	possesses a flat-space metric eta and a universal time
	coordinate t ("prior geometry" {...}); eta acts together with
	matter and nongravitational fields to generate a scalar field
	phi; and then eta, t, and phi combine to create the physical
	metric g that enters into the equivalence principle.  

	All three of the above theories -- Einstein, Dicke-Brans-
	Jordan, Ni -- were viable in the summer of 1971, when this
	section was written.  But in autumn 1971 Ni's theory, and many
	other theories that had been regarded as viable, were proved
	by Nordtvedt and Will (1972) to disagree with experiment.  
	This is an example of the rapidity of current progress in
	experimental tests of gravitation theory!  {pp. 1066-1068.}

-- 

Michael McNeil
3Com Corporation     "All disclaimers including this one apply"
(415) 960-9367
..!ucbvax!hplabs!oliveb!3comvax!michaelm

	Rather than have one global frame with gravitational forces
	we have many local frames without gravitational forces.  
		Stephen Schutz, statement in January 1966
		final examination in course in relativity,
		Princeton University

	[To Ernst Mach, regarding confirmation at a forthcoming eclipse]
	... If so, then your happy investigations on the foundations of
	mechanics, Planck's unjustified criticism notwithstanding, will
	receive brilliant confirmation.  For it necessarily turns out
	that inertia originates in a kind of interaction between bodies,
	quite in the sense of your considerations on Newton's pail
	experiment.  The first consequence is on p. 6 of my paper.  
	The following additional points emerge:  (1) If one accelerates
	a heavy shell of matter S, then a mass enclosed by that shell
	experiences an accelerative force.  (2) If one rotates the shell
	relative to the fixed stars about an axis going through its
	center, a Coriolis force arises in the interior of the shell;
	that is, the plane of a Foucault pendulum is dragged around
	(with a practically unmeasurably small angular velocity).  
		Albert Einstein's appreciation to Ernst Mach, written on
		June 25, 1913, while working hard at arriving at his
		November 1915 formulation of standard general relativity