Papworth Astronomy Club

Cosmology has always been of interest to Club members and therefore the talk by Carolin Crawford on “A Beginners Guide to Cosmology and Dark Energy” was much enjoyed and appreciated. As well as being a staff scientist at the Institute of Astronomy, Carolin is also a public outreach officer, and her talk reflected the care she takes to make complex information understandable by a lay audience.

The talk started with an introduction to the discoveries in the mid 20th century that led to our current understanding of the universe. Einstein’s General Theory of Relativity produced different scenarios for the fate of the universe depending on a mathematical device, the Cosmological Constant. Subsequent observational work by Edwin Hubble showed that in fact the universe is expanding. Given that it started out at the Big Bang, the universe was estimated to be over 14 billion years old.

More recent observations of supernovae and galaxy clusters were described, which imply that the rate of expansion is actually increasing, giving a revised figure of 13.7 billion years for the age of the universe. The force driving this expansion is known as Dark Energy, but the nature of this energy is one of the great mysteries of modern cosmology. Carolin’s talk prompted a range of questions, some of which inevitably verged on the philosophical given the nature of the subject. The evening gave us plenty to think about as we looked up at the Papworth night sky on the way home!