Gravitational waves were first directly detected by which observatory?
- LIGO
- VIRGO
- GEO600
- KAGRA
Answer: LIGO
LIGO (Laser Interferometer Gravitational-Wave Observatory) made the first direct detection of gravitational waves in 2015 (announced 2016), confirming Einstein's 1916 prediction. Waves originated from merging black holes 1.3 billion light-years away. Nobel Prize in Physics 2017. [[NCERT Physics Class 11, IUCAA Reports]]