The London Daily Newsletter Wednesday 31 May

On 31 May 1919, Einstein’s Theory of Relativity was put to the test. The total eclipse of the Sun has been the subject of scientific interest ever since the time of the Ancient Babylonian astronomers, but of all the thousands of eclipses studied by scientists, the eclipse of 31 May 1919 was the most important. It was able to provide the clinching evidence in favour of one of the most revolutionary ideas in the history of physics, namely Einstein?s theory of general relativity. Although general relativity was a radically new formulation of gravity, its predictions were largely consistent with Newton?s highly successful theory of gravity. However, Einstein?s theory did make one or two predictions which distinguished it from Newton?s theory, and, if true, these predictions would show that Einstein?s model was closer to reality. For example, Einstein predicted that a gravitational field should bend rays of light much more than was expected by Newton?s theory of gravity. Although the effect was too small to be observed in the laboratory, Einstein calculated that the immense gravity of the massive sun would deflect a ray of light by 1.75 seconds of arc ? less that one thousandth of a degree, but twice as large as the deflection according to Newton, and significant enough to be measured. Einstein pictured a scenario whereby the straight line of sight between a star and an observer on Earth would be just blocked by the edge of the Sun. Einstein believed that the star would still be visible because gravity would bend the rays of light around the sun and towards the earth. The sighting of a star that should have been blocked by the sun would prove Einstein right, but it is generally to impossible to see starlight that passes close to the Sun, because it is swamped by the brilliance of the sun itself. However, during an eclipse, the Sun is blacked out by the Moon, and under such conditions a gravitationally distorted star should be visible. General relativity was born in 1915 during the First World War, and as soon as the war ended the Astronomer Royal Sir Frank Dyson began preparing for the next total eclipse, which would occur on 29 May 1919, and which would be an opportunity to test Einstein?s theory. He had already recruited Arthur Eddington, Plumian Professor of Astronomy at Cambridge, to make the observations, a decision that was largely a consequence of Eddington?s pacifist beliefs. The son of devout Quakers, Eddington had nearly spent the war as a conscientious objector peeling potatoes in an army camp, but instead Dyson had arranged for a letter of deferment, which allowed him to carry on his astronomical research. However, in return, Eddington had to promise to make the trek to the island of Principe, off the coast of West Africa, one of the best locations for observing the 1919 eclipse. The eclipse seemed almost too good to be true. Totality would last for 410 seconds, almost seven minutes, which is extraordinarily long for an eclipse, and which would provide plenty of opportunity for measurements to be taken. Also, the eclipse would occur against the rich background of the Hyades constellation, increasing the likelihood for an appropriately positioned star. However, as the vital day approached a cloud, or rather several, loomed on the horizon. It rained every day for the nineteen days prior to the eclipse, and as the eclipse began on 29 May, the sun was obscured by clouds. For 400 seconds the eclipse was hidden from view, and throughout this period Eddington prayed. Then with only ten seconds of the eclipse remaining, the skies miraculously cleared, and he was able to take just one meaningful photograph. Eddington compared his eclipse photos with images taken when the sun was not present, and announced that the sun had caused a deflection of roughly 1.61 seconds of arc, a result that was in agreement with Einstein?s prediction, thereby validating the theory of general relativity. Eddington?s result was hailed as a wondrous piece of science, experimental validation of the greatest intellectual achievement of the of the youthful twentieth century, a sign of optimism in a world that had been torn apart by war. J.P. McEvoy, author of the ?Eclipse?, encapsulated the significance of the announcement: ?A new theory of the universe, the brain-child of a German Jew working in Berlin, had been confirmed by an English Quaker on a small African island.?

Stirling Corner
Stirling Corner is the road junction of the A1 Barnet Bypass and Barnet Lane.

A Mr Stirling opened a garage at the junction – hence both Stirling Corner and Stirling Way. This dual carriageway was part of a 1920–4 road improvement programme that was mentioned in parliament in 1928 as “hopefully being completed by the end of the summer”. The A1 northbound carriageway passes the entrance to Scratchwood, an area of ancient forest which is now a Local Nature Reserve, then crosses the A411 from Watford to Barnet at the Stirling Corner roundabout. A proposed link road at this roundabout, estimated at £22.8m in 1987, would have provided access to the M1, but the plans were subsequently abandoned. The link had been planned during discussions for the Hendon Urban Motorway, which was intended to carry the M1 all the way down to Hyde Park Corner as part of the London Ringways scheme; the interchange would have been junction 3 on the motorway. Past Stirling Corner, the A1 skirts Borehamwood, before turning northeast and running through open countryside to Bignell’s Corner.

TUM Book Club: Tube Mapper Project
Photographer Luke Agbaimoni created the Tube Mapper project allowing him to be creative, fitting photography around his lifestyle and adding stations on his daily commute.

The Underground is the backbone of the city of London, a part of our identity. It’s a network of shared experiences and visual memories, and most Londoners and visitors to the city will at some point have an interaction with the London Underground tube and train network. Photographer Luke Agbaimoni gave up city-scape night photography after the birth of his first child, but creating the Tube Mapper project allowed him to continue being creative, fitting photography around his new lifestyle and adding stations on his daily commute. His memorable photographs consider such themes as symmetry, reflections, tunnels and escalators, as well as simply pointing out and appreciating the way the light falls on a platform in an evening sunset. This book reveals the London every commuter knows in a unique, vibrant and arresting style.

Entrance to the Fleet River, c. 1750

Samuel Scott

Video: Co-ordinate near to Gardner Close, Wanstead
Jago Hazzard went to the far reaches of the Central Line