The Earth is a changeable place. At present mankind is dealing with the impacts of a changing climate and a rising sea. But looking back in time, conditions have always varied. The continents have drifted, sometimes apart, sometimes together, and oceans have come and gone. Even the air has changed: it would have been unbreathable for humans as recently as a billion years ago. There have been ice ages and hot houses.
At times the Earth was frozen over completely, with glaciers even in the tropics, and at other times it was too hot for complex life to survive. Prof Zijlstra discusses what caused the Earth to change so much – and what would the Earth have looked like 1, 2 or even 4 billion years ago.
Some of the changes are rooted in astronomy: they were caused by the changes to the orbit of the Earth and even by the evolution of the Sun itself. Some are caused by geological processes, such as the changing configurations of the ocean and continents and the cooling of the mantle. Some are caused by life itself which changed the composition of the atmosphere and affected the delicate temperature balance. And some were caused by accidents, from asteroids which impact Earth and left their giant craters.
Professor Albert Zijlstra is Professor of Astrophysics at the University of Manchester, and Hung Hing Ying Distinguished Visiting Professor at the University of Hong Kong where he is attached to the Department of Physics and the Laboratory for Space Research. He was Director of the UK’s Jodrell Bank Centre for Astrophysics from 2010 to 2015. Jodrell Bank is the largest astronomy group in the UK and operates the iconic Lovell Telescope.
Prof Zijlstra obtained his PhD from the University of Groningen. He has been employed at a variety of observatories around the world, including the South Africa Astronomical Observatory, the National Radio Astronomy Observatory in the USA, and the European Southern Observatory in Germany and Chile. Prof Zijlstra has published more than 600 articles. His main area of research is the final stages of the evolution of stars and his work on the future of the Sun received wide-spread coverage recently.
Members of the RGS, their guests and others are most welcome to attend this event, which is HK$150 for RGS Members and HK$200 for guests and others including a complimentary glass of white or red wine.
The Royal Geographical Society – Hong Kong wishes to express its thanks to Executive Centre for its generous assistance with this event.