It’s ninety years since the 1919 total eclipse of the sun, in which Sir Arthur Eddington provided the first bit of experimental evidence for General Relativity, and shot Einstein to public prominence. What Eddington did was to measure the deflection of the light from stars as it passed close to the large mass of our sun – an eclipse was obviously needed because otherwise stars close to the sun are unobservable. The results were in agreement with what Einstein had predicted a few years earlier and this event really opened up our understanding of the universe.
Eddington was dispatched to the tiny island of Principe, off the west coast of Africa, to view this event. ‘Field trips’ for physicists are fairly rare events – the biologists, earth scientists, oceanographers etc here at The University of Waikato are constantly going out on exciting field trips to the beach, the central North Island volcanoes, or some beautiful patch of native bush, whereas the best us physicists usually manage is a trip up to a company’s offices in Auckland, and the odd conference. Hardly a field trip. With that in mind, I can’t help thinking that Eddington probably wasn’t too prepared for Principe – even now it is not particularly accessible. Richard Massey from the Royal Observatory Edinburgh, reports that it takes four flights to get there from Edinburgh – some of which only run once a week. Eddington’s logistic achievement in simply getting there with the equipment needed was no mean feat in itself. Maybe Einstein just did the easy bit – thinking up the theory – and leaving the small annoying problem of proof to someone else to sort out.
Have a read of Richard Massey’s anniversary report from Principe – quite amusing.