Dark energy and the ever-expanding Universe - Professor Carolin Crawford – Wednesday 21st September 2016

Photo by: Morton Hardaker 

Photo by: Morton Hardaker 

This lecture was given by Carolin Crawford, an experienced observational astronomer who also has a significant role in the public communication of science.  

A rapt audience of sixty-five was treated to fast-paced summary of the more recent history of Cosmology. Professor Crawford’s exciting, accessible talk was enjoyed by all. 

The topic focused on key questions. How did the Universe begin? What will happen to it in the future? The talk began with the concept of gravity as the key player in the Universe. It was Newton who was able to demonstrate the physical cause that kept the planets in orbit around the Sun. Newtonian mechanics was phenomenally successful, but was unable to explain everything. One of its failures was in explaining the precession of Mercury. 

The talk jumped to the early 20th century and Einstein. His field equations did away with Newton’s ideas and instead relied on a geometric description of space and time. The mass of bodies in space curved the space-time around it; the bigger the mass the greater the curvature. The theory explained things where Newton’s theory had failed.

A Universe containing other galaxies arrived with the observations of Edwin Hubble. As did the idea of an expanding Universe and, consequentially, the theory of the Big Bang. 

The rate at which this expansion has taken and is taking place was key to the rest of the lecture. The idea of Dark Matter was introduced to explain the motion of galaxies, the large scale structure of the universe and the structure of Cosmic Background Radiation. The concept of Dark Energy was then needed to explain the unexpectedly faster acceleration of the expansion of the Universe.

It was encouraging for the Society that even more younger members are attending our lectures. We seem to be experiencing our own period of expansion.