# Review on the proving method of general relativity theory that was carried out by Arthur Stanley Eddington

There are two kinds of Einstein’s theory of relativity. The first theory is special relativity announced in the year 1905 with the famous equation of E = mc2, that describes the propagation of matter and light at high speeds.

The second theory, general relativity, was announced in 1915. This theory was born stimulated by the new fact just realized later on by Einstein that his theory on Special Relativity was found to be inconsistent with the gravity theory of Newton, declaring that the space objects pull to each others with the force whose magnitude is determined by distance between the said objects.

His hypothesis in theory on special relativity that the light velocity is the highest speed in this universe is in controversy with the gravity of Newton. The velocity of force attracting to each others among objects at the space, for example the attracting force of the moon causing the change in short time in the form of movement of sea tide on earth has the meaning that the gravity effect spreads at the boundless speed, not at the light velocity or lower.

At his theory on general relativity, Einstein declared a new law on gravity, stating that gravity was not a force as commonly known at the Newton’s gravity theory, but a part of inertia.. His gravity law illustrated the object behaviour at the gravity field, for instance the planets, not in the sense of  ‘the attracting forcer’ but only in the sense of  the crossing track being taken. For Einstein, gravity is a part of inertia. The movement of stars and planets originates from their inertia derivation, and the crossing track taken is determined by the space metrical nature, or more precisely the continuous space-time..

“Einstein’s Law of Gravitation contains nothing about force. It describes the behaviour of objects in  a gravitational field – the planets, for example – not in terms of ‘ attraction ‘ but simply in terms of the paths they follow. To Einstein, gravitation is simple part of inertia; the movement of the stars and the planets arise from their inherent inertia; and the courses they follow are determined by the metric properties of space – or, more properly speaking,  the metric properties of the space-time continuum “  (Lincoln Barnett,  The Universe and Dr. Einstein, London, June 1949,  page 72 ).

At his theory on general relativity, Einstein concluded that the light just as other material objects, moved in curve if gravity field of an object was massive. Einstein suggested that his hypothesis could be tested to  observe  the crossing track of the star light at gravity field of the sun. Due to the fact that the stars are not visible at day time, there is only one chance when the sun and the stars can be seen together at the sky, and that is the time  when there is a solar eclipse.

He suggested that the photo taken to the stars at the time when the sun was dark during the solar eclipse was compared to the photo of the same stars taken at other time  / at night time. According to his hypothesis, the star light visible around the sun would be bent inwards, toward the sun at the time when passing through the gravity field of the sun, so that the picture of the stars would be visible for the observers on earth shifting outwards from their actual position in the sky. Einstein calculated the level of their  deviation and predicted that for the stars observed being the closest to the sun, their deviation was about 1.75 arc second.

The proving method of a theory as suggested by Einstein was recorded at the bookThe Universe and Dr. Einstein’ written by Lincoln Barnett, published for the first time in London in June 1949. The Preface of this book was written by Albert Einstein himself.

“From these purely theoretical considerations Einstein concluded that light, like any material object, travels in a curve when passing through the gravitational field of a massive body. He suggested that his theory could be put to test by observing the path of starlight in the gravitational field of the sun. Since the stars are invisible by day, there is only one occasion when sun and stars can be seen together in the sky, and that is during an eclipse.

Einstein proposed therefore, that photographs be taken of the stars immediately bordering the darkened face of the sun during an eclipse and compared with photographs of those same stars made at another time. According to his theory, the light from the stars surrounding the sun should be bent inward, toward the sun, in traversing the sun’s gravitational field; hence the images of these stars should appear to observer on earth to be shifted outward from their usual positions in the sky.

Einstein calculated the degree of deflection that should be observed and predicted that for the stars closest to the sun the deviation would be about 1.75 seconds of an arc.

Since he staked his whole General Theory of Relativity on this test, men of science throughout the world anxiously awaited the findings of expeditions which journeyed to equatorial regions to photograph the eclipse of May 29, 1919. When their pictures were developed and examined, the deflection of the starlight in the gravitational field of the sun was found to average 1.64 seconds – a figure as close to perfect agreement with Einstein’s prediction as the accuracy of instruments allowed.“ (Lincoln Barnett,  The Universe and Dr.Einstein, London, Victor Gollanez LTD, First Published June 1949, Preface by Albert Einstein, page 78-79 ).

The proving method as suggested by Einstein was carried out by a team of English scientists led by Arthur Stanley Eddington.

Based on data from the Royal Astronomical Society, Arthur Eddington aimed to the group of Hyade stars from the city of Oxford in England at the nights in the months of January and February 1919. After that, Eddington together with his team left for Principe Island in West of Africa, and aimed to the Hyade stars during the solar eclipse on the date of May 29, 1919 at the city of Roca Sundy.

In the month of May 1919 the weather in Principe was not favourable because it was cloudy, and so was the time before the eclipse. However, Eddington succeeded in taking the photo of the solar eclipse taking place for 6 minutes 30 seconds. And the calculation output on light deviation by Arthur Eddington was 1.62 second arc, close to the Einstein’s calculation output of 1.75 second arc.

The proving method for hypothesis as suggested by Einstein as the theory founder should not be able to be carried out, considering the fact that in scientific exposure in astronomy, the instant observation applies. It means, all calculations to determine the ‘true position’ and the ‘apparent position’ of a certain star at the sky is only applicable at a certain time and at a certain place on which such observation is performed.

The observation on a star conducted twice from the places with different geographical positions will result the different height and azimuth of the star. The height and azimuth of a star indicates the position of the star at the time when the observation is performed. The height and azimuth of a star changes every time due to the daily movement of the said space objects. Therefore, the proving method as conducted by Arthur Eddington, should not be able to be performed. Moreover, the observation / photo taking for the stars were performed twice with sufficiently long different interval of time.

In astronomy, the light deviation is something very common, and not caused by gravity field of a massive object, but it occurs due to  the light refraction. Light refraction causes the light of all objects in the sky reaching the earth and seen by the observers, has been deviated by the media to pass through, including the light bending by the earth atmosphere. The magnitude of light deviation in astronomy is known as “Astronomical Refraction”, and can be calculated by using the Snell’s Law.

Conclusion :

The proving method on the theory on general relativity as requested by its founder, Albert Einstein, is unjustifiable from scientific point of view of the astronomy. In addition, a hypothesis stating that the light is bent by gravity of massive object ignores the existence of light refraction (Snell’s Law).

It is really hard to understand that the proving method was conducted by a team led by Arthur Eddington. Therefore, output of the said proving performed by Arthur Eddington must be rejected. Moreover later on it was found out that based on the data from RAS (Royal Astronomical Society) that in the year 1919 RAS had sent two teams of expedition, namely Arthur Eddington and Edwin Cottingham to Principe Island in West of Africa, Andrew Crommelin and Charles Davidson to Sobral in North East of Brazil.

Calculation output of Arthur Eddington’s team was 1.62 second arc, while the calculation output of Andrew Crommelin was 0.93 second arc. This very vivid difference was ignored as if the expedition team performing the measuring from Sobral never existed.

If a scientist conveys a theory and at the same time shows its proving method, however after being tested by another scientist it is found out that his proposed proving method is proven to be unable to be performed due to not being scientific, then automatically such proposed theory prematurely falls by itself. And the proving cannot be  carried out by other methods not  as requested by the theory founder, since it is reasonably assumed that such proving is made based on belief.

Other References:

1. Bowditch, American Practical Navigator, Volume I – II, Defense Mapping Agency Hydrographic / Topographic Center, 1984.