Pune: More than 100 years after Albert Einstein proposed his theory of general relativity, the world’s largest analysis of gravitational waves from colliding black holes has found that its laws still hold true, even under the most extreme conditions in the universe.The research, carried out by LIGO-Virgo-KAGRA (LVK) Collaboration, analysed 77 new and 91 previously studied black hole mergers under the most violent collisions and found no evidence that gravity behaves differently from Einstein’s predictions.Rather than relying on a single measurement, researchers performed a wide range of complementary tests. These included checking whether different stages of the gravitational-wave signal—the inspiral, merger and ringdown—are mutually consistent, searching for tiny distortions predicted by alternative theories of gravity, testing whether gravitational waves propagate exactly as predicted by Einstein’s theory, and examining whether the final black hole behaves according to the famous “no-hair theorem”, an official release from Inter-University Centre for Astronomy and Astrophysics in Pune said.Apratim Ganguly, a researcher from IUCAA, said, “The latest observing run has delivered several exceptional gravitational-wave events, including the loudest signal ever detected. The data has enabled the most comprehensive tests of GR performed using compact binary mergers. Though we find no evidence for deviations from Einstein’s theory, these results place significantly tighter constraints on possible alternatives and highlight the tremendous scientific potential of the rapidly growing gravitational-wave catalog.” Ganguly contributed to the coordination and scientific presentation of this work as the editorial team chair.India’s contribution came through the LIGO-India Scientific Collaboration (LISC), a consortium of researchers from 17 institutions preparing for the upcoming LIGO-India observatory in Maharashtra. Although LIGO-India is still under construction and did not contribute observational data, Indian researchers played a crucial role in reviewing, validating and coordinating the scientific analyses behind the study.
