Physics Nobel prize 2011: Establishing distance scales in the universe
Raman Research Institute, Bangalore.
The physics Nobel prize in 2011 was awarded to three optical astronomers for the discovery of accelerating universe, based on their study of high redshift supernova. This was the culmination of a long standing effort starting in 1920s to measure extra-galactic distances. I shall trace part of the history of this endeavour and discuss how a 'distance ladder' is built on cosmological scales. This year's Nobel prize is also another vindication of the background model of the universe, first stated in its present form by Einstein in 1917. The discovery of acceleration of the universe is remarkable because it indicates the presence of 'dark energy', a form of energy beyond the realm of normal 'matter'. Since 1998, when the acceleration of the universe was first reported by the recipients of this year's Nobel prize, other observations have also strongly supported this evidence. I shall also briefly discuss the ongoing efforts and future of this area of research in cosmology.