HYBRID – General Meeting – March 2025

Main Presentation at 7:30 PM

Following the lecture, the 21” Raymond E White, Jr Telescope will be open, weather permitting.

Title: THE ACCELERATING EXPANDING UNIVERSE: DARK MATTER, DARK ENERGY, AND EINSTEIN’S COSMOLOGICAL CONSTANT

 Dark energy is the leading candidate for the mechanism that is responsible for causing the cosmological expansion to accelerate. In this non-technical talk, Professor Bharat Ratra will describe the astronomical data which persuade cosmologists that (as yet undetected) dark energy and dark matter are by far the main components of the universe’s current energy budget. He will review 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. Professor Ratra will also discuss the basic physics, and the history of ideas, on which this model is based.

Biography: 

Bharat Ratra, distinguished professor of physics at Kansas State University, earned his Master of Science at the Indian Institute of Technology, Delhi, and his doctorate at Stanford University.  In 1988, Ratra and Jim Peebles proposed the first dynamical dark energy model. Ratra joined Kansas State University in 1996. He is best known for his work on dynamical dark energy and on the quantum-mechanical generation of energy density and magnetic field fluctuations during inflation. Recipient of many awards, his most recent is the American Physical Society’s 2025 Julius Edgar Lilenfeld Prize, which recognizes outstanding contributions to physics and exceptional skills in lecturing to diverse audiences.