Humanists reject theistic accounts of the origin of life on our planet in favour of scientific explanations. Is the development of life on earth unique or common throughout the universe and what role does planetary atmosphere play in whether or not life develops? Our speaker for our August meeting was Alan Hunton. Alan says of his talk,

“The Sun, the Earth and the other planets of the Solar System were formed 4.5 billion years ago. In this talk we will examine how conditions on planet Earth have evolved but we will do so by looking closely at our atmosphere. It will be clear that the atmosphere has played a key role in enabling life to develop from single celled organisms to the advanced lifeforms that exist today. The appearance of atmospheric oxygen after about 2 billion years was a real awakening. We will see that the atmosphere has not gradually changed over the history of the Earth but has undergone many quite rapid alterations in response to changes in temperature or the behaviour of the Sun. The listener may wish to consider if the sequence of events is an expected consequence of our planet being in a favourable location: if so, a similar pattern should have occurred elsewhere in the galaxy. Alternatively, is the sequence so unpredictable that it is pure chance that intelligent life has evolved here?”