Major Advances in Radio Astronomy: Some Key Questions Today

Abstract

During the last six decades, several outstanding discoveries have been made in the field of radio astronomy. These have revolutionized our understanding of the mysteries of the Universe. Observations of radio galaxies and quasars that emit extremely powerful radio waves indicate presence of supermassive black holes at their centre. Discovery and detailed observations of the 2.7 K cosmic microwave background temperature have provided strong support to the Big Bang Model of the Universe, giving tight constraints on the relative contributions of baryons, dark matter and dark energy in the Universe. Observations of the emission line of neutral hydrogen from spiral galaxies provide information about the formation and evolution of galaxies. Over 150 molecules have been discovered in the interstellar medium, giving details about the physics and chemistry of the interstellar space; these are also ingredients of life in the Universe. Discovery of Pulsating Radio Sources (Pulsars) have provided strong support to the models of neutron stars that are end products of a star when its ‘nuclear fuel’ runs out. Observations of Pulsars also provide tests of the General Theory of Relativity. I also summarize some of the investigations that are being carried out currently with the Ooty Radio Telescope in South India and with the Giant Metrewave Radio Telescope near Pune; these are amongst the largest radio telescopes in the world. Finally, I describe some of the Key Questions today.