As Fred Archenhold pointed out in the Vote of Thanks, it was a first for Headingley Rotary to have a Fellow of the Royal Society as guest speaker… a great privilege. Our speaker was Prof. Alan Watson of Leeds University and his subject was “Creating a cosmic ray observatory the size of West Yorkshire in Argentina – a $50m project”. He explained what a cosmic ray is, how it travels to earth and how it can be detected (and provided a handout with the basic physics explained). He recounted how he became involved in cosmic ray research in the 1960’s with his involvement with the British national research project to detect rays at Haverah Park near Beckwithshaw, Harrogate which concluded in 1987. One conclusion was that a much larger area was needed to collect meaningful data. The whole subject had gathered momentum during the 1980’s following a discovery at Kiel. Jim Cronin, a Nobel prize-winner spent four months in Leeds and a plan was hatched to obtain a larger site.
Alan took us through the planning of the project which resulted in the Pierre Auger Observatory in Argentina. Argentina was chosen as it met the site requirements (large flat area with few landlords within certain latitudes) and because the country would fund some of the costs. Fund raising and scientific collaboration was carried out on an international scale. He singled out a visit to Vietnam as being particularly successful – one of the political leaders was a physicist. The legacy of this co-operation survives today as the Observatory is operated by 400 scientists from 17 countries. Care was taken too to involve the local community – school children were asked to name the many water tanks involved, but even so there have been problems as land changes hand.
Research to date shows that the rays emanate from outside our galaxy. This knowledge enables theoretical physics to be tested at the limits, but what exactly this will lead to is, at this stage, is anyone’s guess – it is only when one looks back one can make a link between one break-through and the next. His interesting illustrated talk was pitched at a level the non-scientific of us could follow and a lively question and answer session followed.