Golden Jubilee participant Professor John Mainstone and his great-nephew, 11-year-old Stephen Dowding of ÑÇÖÞ²ÊÆ±¹ÙÍø. Professor Mainstone, who graduated from the University of ÑÇÖÞ²ÊÆ±¹ÙÍø in 1959 with a PhD in Physics, has been custodian of the University of Queensland's famous pitch drop experiment, the world's longest running laboratory experiment, since 1961. Photo by John Hemmings