Astronomical equipment used to test Einstein's Theory of Gravity has been shipped from the Dublin Institute for Advanced Studies (DIAS) to Sobral in Brazil to commemorate the 100th anniversary of the observations that confirmed the predictions of Albert Einstein.
The Grubb Coelostat and Einstein Lens are usually housed at the DIAS Dunsink Observatory but will remain on loan to the Sobral Museum in Brazil until August, when they will feature in an exhibition in Dublin to mark 100 years of astronomical development.
The Grubb Coelostat reflects light from the sky onto a fixed telescope, and the Einstein Lens is used to focus the light onto a photographic plate. Both were manufactured by Howard Grubb – one of the most famous telescope makers in the world in the early 20th Century – at his optical works in Observatory Lane, Rathmines, Dublin.
The equipment was used during a solar eclipse on May 29th. In 1919, Einstein's Theory of General Relativity – an experiment coordinated by astronomer and physicist Arthur Stanley Eddington and led, tested in Sobral, by Andrew Crommelin, a native of Co. Antrim
Four years before, in 1915, Albert Einstein had predicted that when a solar eclipse occurs, starlight would be deflected at a small amount, with the amount of deflection increasing closer to the Sun. The specialist equipment, manufactured in Ireland, has a very small effect and is now returning to Sobral for the first time in 100 years.
Eddington Tests Einstein's General Theory of Relativity
Professor Tom Ray of DIAS is in Sobral today to mark the centenary of Eddington's and Crommelin's experiment. Commenting today, he said: “The effects observed by Crommelin in Brazil 100 years ago – using this Irish equipment – key to Eddington was testing Einstein's General Theory of Relativity. When the results were announced later the same year, they made front-page news across the globe.
"It is fantastic to be here in Brazil to mark this centenary and highlight the significant role Ireland played in proving Einstein right. On the morning of the eclipse, the other equipment did not work properly but the Grubb Coelostat and lens saved the day. Eddington himself said that the strongest evidence for Einstein was right from the lens and coelostat from Ireland.
"There has been huge public and media interest here in Brazil in fact that the equipment is traveling all the way from Dublin back to Sobral after 100 years. This is a timely reminder of Ireland's legacy and ongoing leadership in the fields of theoretical physics, astronomy and astrophysics. ”
Also commenting today, Professor Denjoe O'Connor, Senior Professor of Theoretical Physics, DIAS, said:“ The measurements from The 1919 eclipse established that the old Newtonian theory of gravity was inconsistent with the new observations while Einstein's theory of general relativity explained the measurements. This forced physicists to replace the old Newtonian theory with Einstein's theory of gravity where the metric of spacetime is a dynamic variable.
"With the advent of quantum theory years later the challenge became and remains to make these two theories of nature into a consistently larger theory encompassing both, ie into a theory of quantum gravity. We at DIAS are actively engaged in this endeavor. ”