Dr. Bharat Ratra, Distinguished Professor of Physics, Kansas State University, USA, delivered an Institute lecture on “The Accelerating Expanding Universe: Dark Matter, Dark Energy, And Einstein’s Cosmological Constant” on March 14, 2023.

Dark energy is the leading candidate for the mechanism that is responsible for causing the cosmological expansion to accelerate. Dr. Ratra described the astronomical data which persuades cosmologists that (as yet undetected) dark energy and dark matter are by far the main components of the energy budget of the universe at present. He reviewed how these observations have led to the development of a quantitative “standard” model of cosmology that describes the evolution of the universe from an early epoch of inflation to the complex hierarchy of structure seen today. In what was a non-technical lecture, he also discussed the basic physics, and the history of ideas, on which this model is based.

Dr. Ratra is a physical cosmology theorist investigating dark energy and dark matter that constitutes 95% of the universe’s current energy budget. His 1988 discovery, alongside Dr. Jim Peebles of Princeton University, of dynamical dark energy models launched him on a 30+ years quest to evaluate dark energy models using observational data. The implications of Dr. Ratra’s research on dark energy are revolutionary within the field of physics.

Dr. Ratra has authored more than 140 scholarly works and has been cited over 20,000 times in the scientific literature.