At this well attended meeting Colin Humphrey gave a very interesting talk on the age of the earth.
In an Age of Ignorance, until mid 17th cent, western thinking about the age of the earth was polarised. At first, eternalist philosophers like Aristotle thought the earth had always been here. Later, scriptural literalists like archbishop Ussher took the opposite view. In 1650 he declared in Annals of the Old Testament that creation began on the evening preceding Sunday 23 October 4004 BC. Many authors at the time were priests, constrained to think of the earth as around 6000 years old.
In the Age of Reasoning, philosophers and priests were replaced by polymaths, whose empirical thinking quickly departed from scriptural literalism. The mistaken concept of a cooling molten earth dominated thinking during the 18th and 19th centuries. Newton and Leclerc calculated cooling at 50,000 to 100,000 years. From 1860 Lord Kelvin led with an age of 98 million years, though by 1899 he had reduced this to 24 million years. Other scientists, from Hutton to Lyell and Darwin assumed gradual geological processes like sedimentation and erosion to take several hundred million years. Some thought periodic natural catastrophe to be more important in shaping the earth. All believed the earth to be millions of years old, and all were wrong, but oh how they argued!
The Age of Science began in the 20th century with an explosion of knowledge. In 1896 Becquerel discovered radioactivity. Within eleven years the Curies, Rutherford and others had explained and calibrated radioactivity, and ages up to 2 billion years were being determined for some earth minerals. Another advance came in the early 1950s with much improved mass spectrometry, and with the realisation that earth was the same age as the meteorites from the asteroid belt – 4.55 billion years. Now it only remained for geologists and palaeontologists to support this age with the explanation that earth's history has been alternations of vastly long periods with very little change, interrupted by sudden catastrophe, repeated again and again.
The talk finished with recent geological evidence for Noah’s Flood, an event which puzzled for centuries. 7600 years ago, in an unusually warm and wet period the Mediterranean overflowed into the low-lying Black Sea basin, in just a few months inundating a region nearly half the area of Britain.
The next meeting is on 20th March at 7.15pm when Dr Ian Stimpson will give a talk entitled "UK Earthquakes and the Centenary of John Milne."
If his last talk is anything to go by then expect a riveting talk on earthquakes and seismology.