On 1993 Press Release of the Nobel Committee in Physics

8/14/2019 On 1993 Press Release of the Nobel Committee in Physics

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C. Y. Lo

Applied and Pure Research Institute

7 Taggart Drive, Unit E, Nashua,

NH 03060, USA

Committee for the Nobel Prize in PhysicsThe Royal Swedish Academy of Sciences

[email protected], [email protected]

[email protected], [email protected],

Comments on the 1993 Press Release of awarding the Nobel Prize in Physics

Dear Sir:

This email informs you that there are serious theoretical errors in your 1993 news release.

First, I want to make clear that I whole heartily appreciate awarding the Nobel Prize Physics for

1993 jointly to Russell A. Hulse and Joseph H. Taylor, Jr. for the discovery of a new type of pulsar, a

discovery that has opened up new possibilities for the study of gravitation. Nevertheless, I also believe

that it is my duty as a scientist to inform you that the related subsequent 1993 news release contents

serious errors that will jeopardize correct understanding of Einsteins theory and future developments

of gravitational theory. Thus, it is necessary to rectify these errors as soon as possible. It is simply not

true, So far, Einstein's theory has passed the tests with flying colours. Apparently, your committee

was ill-advised by incompetent advisors, who failed in understanding non-linear equations.

In fact, as suspected by A. Gullstrand [1], a 1921 member of your committee, Einsteins equation

does not have any solution that can be used to justify his claim of the perihelion motion of Mercury as

a small general-relativity contribution since Einstein failed to show that his approach is mathematicallya valid approximation. Einstein [2], who does not have enough background in mathematics, claimed in

his 1923 Nobel lecture that his considerations led to the theory of gravity which yields the Newtonian

theory as a first approximation and furthermore it yields the motion of the perihelion of Mercury, the

deflection of light by the sun, . However, he did not respond to those questions on perihelion of

Mercury raised by Gullstrand. Although it yields the Newtonian theory as a first approximation for a

testing particle, in general relativity unfortunately there is actually no solution for a two-body problem

just as Gullstrand [1] suspected.

Nevertheless, most peers of Einstein, who also have inadequate background in mathematics,

believed Einstein was right and Gullstrand was too critical. The root of these errors is that they do not

understand non-linear equations. Nevertheless, this issue was finally resolved in my paper of 1995 [3]

published in the Astrophysical Journal, in which I proved that it is impossible for Einsteins equation to

have a two-body solution or a physical gravitational wave solution. The editor-in-chief of this journal

was Subramanyan Chandrasekha, who has very strong background in both mathematics and physics.

However, this paper was essentially ignored by current theorists and they probably failed to read it.

Apparently these findings are surprising to many since they are in direct conflict with what have

been derived from the linearized Einstein equation [4, 5]. They are used to that a weak solution can

always be obtained if the source term is weak enough. However, for a non-linear field equation, a weak

solution may not exist independent of the strength of the source [6-10] although this is inconsistent

with physical principles such as the principle of causality [11]. This is possible because the fieldequation may not be valid for such a situation.
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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Unfortunately, although the static solutions give accurate predictions, there are neither bounded

gravitational wave solutions nor bounded dynamic solutions for the Einstein equation. Thus,

linearization is not a valid mathematical procedure of the Einstein equation for the dynamic cases

although linearization is proven to be valid for the static cases [4, 5]. Because of inadequate

background beyond linear equation in mathematics, many theorists simply cannot understand that the

procedure of linearization is not valid for a dynamic case [11]. Thus, it seems, many theorists in the

field of gravitation simply do not have the ability of self-rectification. They need help.

To prove the above statements rigorously would be complicated and thus not practical in an email.

Some may simply do not have enough patience even if they have the ability to understand them. To

save time, taking a short cut by showing a simple example that illustrates this invalidity would be

useful. A well-known plane wave form considered by Misner et al. [12] is as follows:

ds2

= c2dt

2 dx

2 L

2(e

2dy

2+ e

2dz

2), (1)

whereL = L(u), =(u), u = ct x, and c is the light speed. Then, the field equation becomes

0''

2

2

2

=

+

du

dL

du

Ld . (2)

Misner et al. [12] claimed that eq. (2) has a bounded solution, compatible with a linearization of metric

(1). However, careful analysis shows that eq. (2) does not have a physical solution that satisfies

Einsteins requirement on weak gravity. In fact, L(u) is unbounded even for a very small (u) [13].

Thus, an exact solution for eq. (2) must be irreducibly unbounded.

On the other hand, from the linearization of the Einstein equation (the Maxwell-Newton

approximation) in vacuum, Einstein [14] obtained a solution as follows:

ds2

= c2dt

2 dx

2 (1 + 2) dy2 (1 2)dz2, (3)

where is a bounded function ofu (= ct x). Note that metric (3) is the linearization of metric (1) if

= (u). Note also that the Maxwell-Newtonian approximation [3] can be derived directly fromEinsteins equivalence principle [15]. Thus, the problem of gravitational waves illustrate that the

prevailing linearization may not be valid since eq. (2) does not have a weak wave solution.

Since the Einstein equation has no physical solution for the dynamic case, it is not a valid physical

equation for the dynamic case [16]. Thus, it is not clear that the linearized equation is valid since the

linearized equation is derived from the Einstein equation. However, the Hulse-Taylor experiments on

binary pulsars suggest that the gravitational wave does exist, and thus it should be possible to show

validity of the linearized equation, independent of the Einstein equation. Based on Einsteins

equivalence principle, it has been proven [15] that the linearzed equation is valid for the case that thesources are massive matter. Because of this, such a linear equation is called the Maxwell-Newton

Approximation [3].

Now a question is what is the equation that the Maxwell-Newton Approximation is an

approximation? It has been determined [3, 17] that one should modify the Einstein equation

G R -1

2gR = - K T(m), (4)

to be

G R -1

2gR = - K [T(m) - t(g)], (5)

where T(m) is the massive tensor and t(g) is the energy-stress tensors for gravity. Then,

T(m) = 0, and t(g) = 0. (6)


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Moreover, the Maxwell-Newton Approximation is

1

2

(1)

= - K T(m) . (7)

where

g = + , = (1) +

(2) ; and

(i) =

(i) -

12(

(i)

cdcd),

and (1)is of a first-order; and (2)

the second order. Then, the equation in vacuum is

G R -1

2gR = K t(g) . (5)

Note that t(g)is equivalent to Einstein's gravitational pseudotensor or G(2)(the second order terms

in G) in terms of his radiation formula [3, 17]. When gravitational wave is present, the gravitational

energy-stress tensor t(g) is non-zero as physics requires.

Note that, because of the Maxwell-Newton Approximation (7), the radiation of the binary pulsar

can be calculated without detailed knowledge of t(g). From (5'), the approximate value of t(g) atvacuum can be calculated through G/K since the first-order approximation of g can be calculated

through (7). In view of the facts that Kt(g) is of the fifth order in a post-Newtonian approximation,

that the deceleration due to radiation is of the three and a half order in a post-Newtonian approximation

[18] and that the perihelion of Mercury was successfully calculated with the second-order

approximation from (5), the orbits of the binary pulsar can be calculated with the second-order

post-Newtonian approximation of (5) by using (7).

Thus, the calculation approaches of Damour and Taylor [19, 20] would be essentially valid except

that they did not realize the crucial fact that (7) is actually an approximation of the update equation (5)

[3, 17]. It is interesting that P. Morrison of MIT had gone to Princeton three times to discuss the

calculations of binary pulsars with Taylor [21]. Taylor finally told Morrison that Damour is responsible

for the calculations.

In light of the above, the Hulse-Taylor experiments support the anti-gravity coupling being

crucial to the existence of the gravitational wave [3, 10], and solution of (7) can be an approximation of

weak waves generated by massive matter. Thus, it has been experimentally verified that the Einstein

equation (4) is actually incompatible with the gravitational radiation.

Perhaps, due to the influence of your news release, t Hooft tried to challenge the fact that the

Einstein equation has no gravitational wave solution with an example of his own creation. However, it

turns out that his example is invalid in physics [22] and this also exposes that t Hooft failed to

understand that a field must have sources and that a plane wave is only a local idealization [22]. Thisdemonstrates that, an outstanding applied mathematician may not always be a good physicist.

Another problem of the 1993 news release is that Einsteins equivalence principle was not even

stated correctly. The identity between gravitational and inertial mass was due to Galileo and Newton.

Einsteins equivalence principle states the effect of an accelerated system as equivalent to the effect of

gravity [4, 5]. Thus, according to Einstein, gravity may not necessary due to space-time curvature. The

view that gravity is due to space-time curvature actually comes from Wheeler [12], who finally rejected

Einsteins principles as not valid in 1994 [23]. Thus, your news release also contents statements which

are not only wrong but also factually incorrect.

It should be noted although Einsteins equivalence principle is crucial to general relativity and

almost everybody pays lip service to it, this principle has been practically abandoned. This is supported


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by the fact that no textbook and reference (except Einsteins own) correctly states and explains

Einsteins equivalence principle and the related Einstein-Minkowski condition [24]. This manifests that

most theorists do not understand Einsteins equivalence principle and general relativity. Zhou Pei-Yuan

[25, 26] of Peking University is probably the only theorist who understands the importance of

Einsteins equivalence principle, which Zhou [26] used to reject Einsteins covariance principle.

Einsteins accurate predictions created a faith in his theories, and this makes a critical analysis

overdue. Also, the observational confirmations were exaggerated since his equation has no dynamic

solutions as conjectured by Gullstrand [1]. Currently, some theorists just try to make sense out of any

solution of the Einstein equation.

However, NASAs discovery of the pioneer anomaly would change such a situation because the

data suggest that there would be theoretical problems in Einsteins theory [27-31]. In fact, this is

confirmed because counter examples of Einsteins covariance principle are found. For instance,

calculations of the deflection angle of light to the second order actually show that his covariance

principle is invalid [32-34]. Thus, Einsteins covariance principle is not valid as Zhou [25] pointed out

25 years ago. Moreover, it is also found that Einsteins justification of his measure theory that

Whitehead [35] criticized as incorrect in physics is actually based on invalid applications of special

relativity [36]. Thus, one may wonder whether the so-called experts of general relativity understand

special relativity.

Now, it is clear that Einsteins general relativity was difficult to understand because it is not a

self-consistent theory in its area of application [36].

Moreover, Einsteins own misconception is the primary cause that the necessity of unification

among electromagnetism and gravitation [36-38] was not discovered from his theory earlier. A reason

is that the conditional validity of E = mc2 was not well understood [37, 39, 40]. Nevertheless, Einstein

really was a genius and the full meaning of general relativity is still emerging 100 years after its

creation. For instance, based on general relativity, the charge-mass interaction is identified to be

responsible for the pioneer anomaly discovered by NASA [31].

I trust that you would correct your 1993 news release after adequate studies. And, for the progress

of science, you would also deal with related matter subsequently that would enhance understanding of

gravity. Thank you very much for your kind attention. I am looking forward to hearing from you.

Sincerely yours,

C. Y. Lo

References:

1. A. Gullstrand, Ark. Mat. Astr. Fys. 16, No. 8 (1921); ibid, Ark. Mat. Astr. Fys. 17, No. 3 (1922).2. A. Einstein, Fundamental ideas and problems of the theory of relativity, Lecture delivered to

the Nordic Assembly of Naturalists at Gothenburg, July 11, 1923.

3. C. Y. Lo, Einstein's Radiation Formula and Modifications to the Einstein Equation, AstrophysicalJournal 455, 421-428 (Dec. 20, 1995).

4. A. Einstein, H. A. Lorentz, H. Minkowski & H. Weyl, with notes by A. Sommerfeld, The Principleof Relativity, (Dover, New York, 1952).

5. A. Einstein, The Meaning of Relativity (Princeton Univ. Press, 1954).


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6. C. Y. Lo, Gravitational Waves and Modification of Einstein's Equation, in Proc. Sixth MarcelGrossmann Meeting On General Relativity, Kyoto Univ., Japan, 23-29 June 1991, Ed. H. Sato & T.

Nakamura, Ser. Ed. R. Ruffini B, 1496-1498 (Singapore: World Sci., 1992).

7. C. Y. Lo, Einstein's Radiation Formula and Modifications in General Relativity, The SecondWilliam Fairbank Conference On Relativistic Gravitational Experiments In Space & Related

Theoretical Topics, Hong Kong Polytechnic, Hong Kong Dec. 13-16 (1993).

8. C. Y. Lo, Causality, Symmetry, Gauge, and Validity of Linearized Gravity for Waves, Phys.Essays 7 (4), 453-458 (1994).

9. C. Y. Lo, The Question of Linearized Gravity and Maxwell-Newtonian Approximation, in Proc.Seventh Marcel Grossmann Meeting On General Relativity, Stanford Univ., U.S.A., 24-30 July

1994, Ed. R. Jantzen & M. Keiser, Ser. Ed. R. Ruffini 525 (Singapore: World Sci., 1996).

10. C. Y. Lo, The Question of Theoretical Self-Consistency in General Relativity: on Light Bending,Duality, the Photonic Energy-Stress Tensor, and Unified Polarization of the Plane-Wave Forms,

Phys. Essays 12 (2), 226-241 (June, 1999).

11. C. Y. Lo, On Incompatibility of Gravitational Radiation with the 1915 Einstein Equation, Phys.Essays 13 (4), 527-539 (December, 2000).

12. C. W. Misner, K. S. Thorne, & J. A. Wheeler, Gravitation (W. H. Freeman, San Francisco, 1973).13. C. Y. Lo, Einsteins Equivalence Principle, the Principle of Causality, and Plane-Wave Solutions,

Phys. Essays 20 (3), 494-502 (Sept. 2007).

14. A. Einstein, Sitzungsberi, Preuss, Acad. Wis. 1918, 1: 154 (1918).15. C. Y. Lo, Compatibility with Einstein's Notion of Weak Gravity: Einstein's Equivalence Principle

and the Absence of Dynamic Solutions for the 1915 Einstein Equation, Phys. Essays 12 (3),

508-526 (Sept. 1999).

16. C. Y. Lo, The Gravitational Plane Waves of Liu and Zhou and the Nonexistence of DynamicSolutions for Einsteins Equation, Astrophys. Space Sci., 306: 205-215 (2006f) (DOI

10.1007/s10509-006-9221-x).

17. C. Y. Lo, On Incompatibility of Gravitational Radiation with the 1915 Einstein Equation, Phys.Essays 13 (4), 527-539 (December, 2000).

18. S. Weinberg, Gravitation and Cosmology (John Wiley, New York, 1972).19. T. Damour & J. H. Taylor, Astrophys. J. 366: 501-511 (1991).20. T. Damour & J. H. Taylor, Phys. Rev. D, 45 (6), 1840-1868 (1992).21. C. Y. Lo, Misunderstandings Related to Einsteins Principle of Equivalence, and Einsteins

Theoretical Errors on Measurements, Phys. Essays 18 (4), 547-560 (December, 2005).

22. C. Y. Lo, The Principle of Causality and the Cylindrical Symmetry Metrics of Einstein & Rosen,Bulletin of Pure and Applied Sciences, 27D (2), 149-170 (2008).

23. H. C. Ohanian & R. Ruffini, Gravitation and Spacetime (Norton, New York, 1994).24. C. Y. Lo, Einsteins Principle of Equivalence, and the Einstein-Minkowski Condition, Bulletin of

Pure and Applied Sciences, 26D (2), 73-88 (2007d).

25. Zhou (Chou) Pei-Yuan, On Coordinates and Coordinate Transformation in Einsteins Theory ofGravitation in Proc. of the Third Marcel Grossmann Meetings on Gen .Relativ., ed.Hu Ning,

Science Press & North Holland. (1983), 1-20.

26. Zhou (Chou) P. Y. 1987. Further Experiments to Test Einsteins Theory of Gravitation in Proc. ofInter. Sym. on Experi. Grav. Phys., GuangZhou, China August.


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27. Robert Lee Hotz, Newton, Einstein Lost in Space?Scientist May be Getting Warmer inFinding Why Pioneer Probes Veered off Course, Wall Street Journal, May 16, 2008, PA7.

28. S. G. Turgshev, V. Toth, L. R. Kellogy, E. L. Lau, and K. J. Lee, The Study of the PioneerAnomaly: New Data Objectives for New Investigation arXIV: gr-gc/0512121v2, 6 Mar.

2006.

29. Charles Q. Choi, NASA Baffled by Unexplained Force Acting on Space Probes, SPACE.com, 3March 2008.

30. Richard A. Lovett, Magical mystery tour: the Pioneer anomaly, Issue 21 of Cosmos, June 2008.31. C. Y. Lo,The Mass-Charge Repulsive Force and Space-Probes Pioneer Anomaly, International

Conference on Physical Interpretations of Relativity Theory, Moscow, Russia 6 July 9 July

2009, Bauman Moscow State Technical University, Moscow, 105005, Russia

32. C. Y. Lo, The Deflection of Light to Second Order and Invalidity of the Principle of Covariance,Bulletin of Pure and Applied Sciences, 27D (1), 1-15 (2008).

33. C. Y. Lo, Einsteins Requirement for Weak Gravity, versus Einsteins Covariance Principle,,Physical Interpretation of Relativity Theory: Proceedings of International Meeting. Imperial

College, London, September 12 15 2008/ Edited by M.C. Duffy, V.O. Gladyshev, A.N.

Morozov, P. Rowlands.

34. C. Y. Lo, A Counter Example of Einsteins Covariance Principle, The 16th Annual NaturalPhilosophy Alliance Conference, University of Connecticut, Storrs, May 25-29, 2009

35. A. N. Whitehead, The Principle of Relativity (Cambridge Univ. Press, Cambridge, 1962).36. C. Y. Lo, Some Rectifiable Inconsistencies and Related Problems in Einsteins General Relativity,

Mathematics, Physics and Philosophy in the Interpretations of Relativity Theory II, Budapest, 4-6

Sept. 2009.

37. C. Y. Lo, The Necessity of Unifying Gravitation and Electromagnetism and the Mass-ChargeRepulsive Effects in Gravity, Physical Interpretation of Relativity Theory: Proceedings of

International Meeting. Moscow, 2 5 July 2007/ Edited by M.C. Duffy, V.O. Gladyshev, A.N.

Morozov, P. Rowlands. Moscow: BMSTU, 2007, p. 82.

38. C. Y. Lo, Limitations of Einsteins Equivalence Principle and the Mass-Charge RepulsiveForce, Physics Essays 21 (1), 44 (March 2008).

39. C. Y. Lo, Comments on Misunderstandings of Relativity, and the Theoretical Interpretation of theKreuzer Experiment, Astrophys. J. 477, 700-704 (March 10, 1997).

40. A. Einstein, E = mc2' (from Science Illustrated 1946) inIdeas and Opinions (Crown, New York,1954).

p.s.: The published papers not yet in print are attached.

Attachments:

1) C. Y. Lo,The Mass-Charge Repulsive Force and Space-Probes Pioneer Anomaly, InternationalConference on Physical Interpretations of Relativity Theory, Moscow, Russia 6 July 9 July

2009, Bauman Moscow State Technical University, Moscow, 105005, Russia.

2) C. Y. Lo, A Counter Example of Einsteins Covariance Principle, The 16th Annual NaturalPhilosophy Alliance Conference, University of Connecticut, Storrs, May 25-29, 2009.

3) C. Y. Lo, Some Rectifiable Inconsistencies and Related Problems in Einsteins GeneralRelativity, Mathematics, Physics and Philosophy in the Interpretations of Relativity Theory II,

Budapest, 4-6 Sept. 2009.
mailto:[email protected]://www.cosmosmagazine.com/issues/2008/21/http://www.cosmosmagazine.com/issues/2008/21/mailto:[email protected]


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4) The 1993 News Release of the Nobel Prize Committee13 October 1993

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize Physics for 1993

jointly to Russell A. Hulse and Joseph H. Taylor, Jr, both of Princeton University, New Jersey, USA

for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the

study of gravitation.

Gravity investigated with a binary pulsar

The discovery rewarded with this year's Nobel Prize in Physics was made in 1974 by Russell A. Hulse

and Joseph H. Taylor, Jr using the 300-m radiotelescope at Arecibo, Puerto Rico, West Indies. Taylor,

then Professor at the University of Massachusetts, Amherst, and his research student Hulse were

searching systematically for pulsars - a kind of rapidly rotating cosmic beacon with a mass somewhatgreater than that of the sun and a radius of about ten kilometres. (A human being on the surface of a

pulsar would weigh some hundred thousand million times more than on Earth.) The pulsar's "beacon

light" is often within the radio wave region.

The first pulsar was discovered in 1967 at the radioastronomy laboratory in Cambridge, England

(Nobel Prize 1974 to Antony Hewish). What was new about the Hulse-Taylor pulsar was that, from the

behaviour of the beacon signal, it could be deduced that it was accompanied by an approximately

equally heavy companion at a distance corresponding to only a few times the distance of the moon

from the earth. The behaviour of this astronomical system deviates greatly from what can be calculated

for a pair of heavenly bodies using Newton's theory. Here a new, revolutionary "space laboratory" has

been obtained for testing Einstein's general theory of relativity and alternative theories of gravity. So

far, Einstein's theory has passed the tests with flying colours. Of particular interest has been the

possibility of verifying with great precision the theory's prediction that the system should lose energy

by emitting gravitational waves in about the same way that a system of moving electrical charges emits

electromagnetic waves.

The significance of the discovery of the binary pulsar

The discovery of the first binary pulsar is primarily of great significance for astrophysics and

gravitational physics. Gravity is the oldest known natural force, the one we are most aware of in daily

life. At the same time it is in one sense the force that is hardest to study since it is so much weaker than

the other three natural forces: the electromagnetic force and the strong and the weak nuclear forces.

The development of technology and science since the second World War with rockets, satellites, space

voyages, radioastronomy, radar technology and the precise measurement of time using atomic clocks

has led to a renaissance of the study of this earliest-known natural force. The discovery of the binary

pulsar represents an important milestone in this historical development.

Relativity theory and gravitational physics

According to Albert Einstein's general theory of relativity, gravity is caused by changes in the

geometry of space and time: space-time curves near masses. Einstein presented his theory in 1915 and

became a world celebrity when in 1919 the English astrophysicist Arthur Eddington announced that
http://nobelprize.org/redirect/links_out/prizeawarder.php?from=/nobel_prizes/physics/laureates/1993/press.html&object=kva&to=http://www.kva.se/http://nobelprize.org/nobel_prizes/physics/laureates/1974/index.htmlhttp://nobelprize.org/nobel_prizes/physics/laureates/1974/index.htmlhttp://nobelprize.org/redirect/links_out/prizeawarder.php?from=/nobel_prizes/physics/laureates/1993/press.html&object=kva&to=http://www.kva.se/


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one of the predictions of the theory, the deflection of starlight passing near the surface of the sun - "the

light is drawn towards the sun" - had been verified during solar eclipse expeditions. This deflection of

light. together with a small general-relativity contribution to the perihelion motion of Mercury (a slow

rotation of Mercury's elliptical orbit round the sun), was for several decades the only, partly rather

uncertain, support for Einstein's theory.

For a long time the theory of relativity was considered aesthetically very beautiful and satisfying,

probably correct, but of little practical significance to physics except in applications in cosmology, the

study of the origin, development and structure of the universe.

Attitudes to the general theory of relativity changed, however, during the 1960s when both

experimental and theoretical developments made gravitational physics a topical part of physics. New

opportunities for precise experiments, based on satellite and radar technology, opened up. In particular,

the research of the Americans R. Dicke and I. Shapiro contributed to this. Dicke performed precision

experiments in which the sun's gravitational field on the earth was used for verifying what is termed the

equivalence principle, the identity between gravitational and inertial mass - one of the basic principles

of the general theory of relativity (and also of several alternative gravitation theories). Important

contributions were also Shapiro's theoretical prediction and experimental verification, using radar

echoes from Mercury, of a new consequence of the general theory of relativity - a time-delay effect for

electromagnetic signals passing through gravitational fields.

All these experiments, however, were confined to our solar system with its very weak gravitational

fields and consequently small deviations, hard,to measure, from the Newtonian theory of gravity.

Hence it was possible to test the general theory of relativity and other theories only in the first

post-Newtonian approximation.

The discovery of the binary pulsar

Hulse's and Taylor's discovery in 1974 of the first binary pulsar, called PSR 1913 + 16 (PSR stands for

pulsar, and 1913 + 16 specifies the pulsar's position in the sky) thus brought about a revolution in the

field. We have here two very small astronomical bodies, each with a radius of some ten kilometres but

with a mass comparable with that of the sun, and at a short distance from each other, only several times

the moon's distance from the earth. Here the deviations from Newton's gravitational physics are large.

As an example may be mentioned that the periastron shift, the rotation of the elliptical orbit that the

pulsar (according to Kepler's first law from the beginning of the 17th century) follows in this system, is4 degrees per year. The corresponding relativistic shift for the most favourable example in our solar

system, the above-mentioned perihelion motion of Mercury, is 43 seconds of arc per century (this is

less than a tenth of the very much larger contributions to the perihelion motion caused by perturbations

from other planets, chiefly Venus and Jupiter). The difference in size between the shifts is partly due to

the orbital speed in the binary pulsar, which is almost five times greater than Mercury's, and partly due

to the pulsar performing about 250 times more orbits a year than Mercury. The orbiting time of the

binary pulsar is less than eight hours, which can be compared with the one month our moon takes to

orbit the earth.

A very important property of the new pulsar is that its pulse period, the time between two beacon


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sweeps (0.05903 see) has proved to be extremely stable, as opposed to what applies to many other

pulsars. The pulsar's pulse period increases by less than 5% during 1 million years. This means that the

pulsar can be used as a clock which for precision can compete with the best atomic clocks, This is a

very useful feature when studying the characteristics of the system.

The very stable pulse period is in fact a mean of the pulse period observed on earth over the time of one

orbit of the pulsar system. The observed period actually varies by several tens of microseconds, i.e. by

an amount that is much greater than the variation in the mean value. This is a Doppler effect, and led to

the conclusion that the observed pulsar moves in a periodic orbit, meaning that it must have a

companion. As the pulsar approaches the earth, the pulses reach the earth more frequently; as it recedes

they arrive less frequently. From the variation in pulse period, conclusions can be drawn about the

pulsar's speed in its orbit and other important features of the system.

Demonstration of gravitational waves

A very important observation was made when the system had been followed for some years. This

followed theoretical predictions made shortly after the original discovery of the pulsar. It was found

that the orbit period is declining: the two astronomical bodies are rotating faster and faster about each

other in an increasingly tight orbit. The change is very small. It corresponds to a reduction of the orbit

period by about 75 millionths of a second per year, but, through observation over sufficient time, it is

nevertheless fully measurable. This change was presumed to occur because the system is emitting

energy in the form of gravitational waves in accordance with what Einstein in 1916 predicted should

happen to masses moving relatively to each other. According to the latest data, the theoretically

calculated value from the relativity theory agrees to within about one half of a percent with the

observed value. The first report of this effect was made by Taylor and co-workers at the end of 1978,

four years after the discovery of the binary pulsar was reported.

The good agreement between the observed value and the theoretically calculated value of the orbital

path can be seen as an indirect proof of the existence of gravitational waves. We will probably have to

wait until next century for a direct demonstration of their existence. Many long-term projects have been

started for making direct observations of gravitational waves impinging upon the earth. The radiation

emitted by the binary pulsar is too weak to be observed on the earth with existing techniques. However,

perhaps the violent perturbations of matter that take place when the two astronomical bodies in a binary

star (or a binary pulsar) approach each other so closely that they fall into each other may give rise to

gravitational waves that could be observed here. It is also hoped to be able to observe many otherviolent events in the universe. Gravitational wave astronomy is the latest, as yet unproven, branch of

observational astronomy, where neutrino astronomy is the most direct predecessor. Gravitational wave

astronomy would then be the first observational technique for which the basic principle was first tested

in an astrophysical context. All earlier observational techniques in astronomy have been based on

physical phenomena which first became known in a terrestrial connection.

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On 1993 Press Release of the Nobel Committee in Physics