Leading Astronomer Delivers Public Lecture on Dark Matter and its Influence on our Universe

Posted on: 21 October 2010

Leading astronomer and Clowes Professor of Science at the Harvard-Smithsonian Centre for Astrophysics, Professor Robert Kirshner, gave a lecture entitled Dark Energy and the Accelerating Universe: Einstein’s Blunder Undone!  Organised by TCD’s School of Physics, Professor Kirshner’s lecture addressed the theory that the universe is expanding outwards at an accelerated rate, fuelled by a mysterious ‘dark energy’.

The phenomenon on dark energy was not discovered by scientists until 1998.  Based on a theory that arose from observing exploding stars half way across the observable universe, astronomers discovered that the expansion of the Universe is speeding up.  The explanation for this accelerated cosmic expansion is that it is driven by a mysterious ‘dark energy’ whose nature is not fully understood.  In 1917, Albert Einstein invented the ‘cosmological constant’ as a kind of cosmic repulsion, balancing out gravity to produce a static universe.  He abandoned this theory in the 1930’s when astronomical evidence began to show that the Universe was not static, but expanding, leading to Einstein’s cosmological constant being dubbed as ‘Einstein’s greatest blunder’.  However, recent results now show that a form of dark energy, much like Einstein’s cosmological constant, is needed to explain the universe we live in. 

In this strange new picture of the Universe, dark energy accounts for about 70% of the universe, dark matter about 25%, with only 5% composed of the ordinary matter that makes up galaxies, stars, planets and people.  During his lecture Professor Kirshner detailed the evidence for this new picture of the Universe.  He described how exploding stars highlighted the existence of an energy that was pushing the Universe’s boundaries, causing it to continuously expand.  Astronomers continue to investigate the nature of this dark energy, the driving force behind the cosmic expansion, and its ability to stretch our Universe.

Professor Kirshner is one of the world’s leading astronomers whose research has resulted in surprising and significant breakthroughs on the nature of the Universe.  A graduate of Harvard, he now serves as the Clowes Professor of Science at the Harvard-Smithsonian Centre for Astrophysics.  Professor Kirshner is an author of over 250 research papers dealing with supernovae and observational cosmology.  His work has earned him the Gruber Prize for Cosmology in 2007 and a distinguished alumni award from his alma mater amongst other accreditations.