Murder in the Expanding Universe: Investigating Dark Energy and the Possible Death of the Cosmological Constant

The lecture, delivered by Dr. Basundhara Ghosh, investigates the possible “death” of the cosmological constant through the lens of a film-noir murder mystery. Einstein introduced the cosmological constant in 1917, and it later became central to explaining the accelerating expansion of the Universe. However, new observations, including data from the Dark Energy Spectroscopic Instrument (DESI), have raised questions about whether dark energy behaves as a constant. The lecture will examine the history of cosmology, evidence from galaxies and quasars observed at different cosmic epochs, and possible explanations for the changing picture of the Universe. Dr. Basundhara Ghosh is a faculty member in Physics at Azim Premji University, Bengaluru, specialising in theoretical cosmology. She previously held research fellowships at IISc Bengaluru and Heidelberg University and earned her PhD from the University of Geneva.