Recent Developments of Astronomy and Gravitation

Until the end of the 19th century, astronomy relied on naked-eye or telescopic observation alone. The discovery of the wider electromagnetic spectrum then opened up entirely new ways to observe the universe, and it was around this time that Newton's law of gravitation was found to have small but real discrepancies in certain situations -- discrepancies that Albert Einstein resolved with his general theory of relativity, one of the most successful physical theories of the 20th century.

Through the 20th century, astronomy and gravitation merged into a single, rapidly growing field, with the birth and death of stars becoming far better understood. Several Indian physicists made landmark contributions: Subrahmanyan Chandrasekhar formulated the theory behind black holes and the life-cycle of stars, work that won him the 1983 Nobel Prize; Meghnad Saha discovered the ionization formula (the "Saha ionization formula") used to classify stars; Amal Kumar Raychaudhuri derived the now-famous "Raychaudhuri equation" in general relativity; and Jayant V. Narlikar made pioneering contributions to astrophysics and founded the IUCAA (Inter-University Centre for Astronomy and Astrophysics), a major Indian research institute for gravitation and astrophysics. In 2017, the direct detection of …