Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation?

The answer is B. When two massive black holes spiral into each other and merge, they send ripples through spacetime itself. These are gravitational waves, predicted by Einstein's General Relativity in 1916. The LIGO detectors in the USA registered such a signal in September 2015 (GW150914), and it was announced in February 2016. That is why the 2017 Nobel Prize in Physics went to Weiss, Thorne and Barish.

• A is wrong: The Higgs boson was found at CERN's LHC in 2012. It has nothing to do with black hole mergers.
• C is wrong: Wormholes remain a theoretical idea. No observation supports them, let alone inter-galactic travel.
• D is wrong: A singularity lies inside the event horizon, where no signal can escape. A merger signal cannot reveal it directly.

Core concept: gravitational waves as a new way of observing the universe. This links to GS-III (Science and Technology, space) and to India's LIGO-India project in Hingoli, Maharashtra, which was approved in 2023 and is still under construction.

Trap: Aspirants pick C because wormholes often appear in popular science. Remember that the observation confirmed gravitational waves, not any theoretical shortcut through space.