Why in news?
Scientists from the LIGO‑Virgo‑KAGRA collaboration announced the detection of gravitational waves from a rare black hole merger, codenamed GW231123.
What happened?
On 23 November 2023, detectors in the United States, Europe and Japan observed ripples in spacetime caused by two black holes spiralling into each other. One black hole weighed about 100 times the mass of our Sun and the other about 140 solar masses. They merged to form a single black hole around 225 solar masses, spinning near the theoretical limit.
Why is it unusual?
- Black holes of this size fall into a “mass gap” where current models predict they are unlikely to form directly from dying stars because of a phenomenon called pair‑instability. The observation suggests that they might have grown through previous mergers (hierarchical mergers) or formed from exceptionally massive stars.
- The detection demonstrates the increasing sensitivity of gravitational‑wave observatories and enriches our understanding of the population of black holes in the Universe.
Significance
Such events test Einstein’s General Theory of Relativity under extreme conditions and shed light on how heavy black holes and galaxies evolve. They may also provide clues about the early Universe, where massive stars and dense star clusters were more common.