RAS question
Gravitational waves were first directly detected in 2015 by:
Correct answer: (B) LIGO.
Gravitational waves were first directly detected in 2015 using LIGO, the Laser Interferometer Gravitational-Wave Observatory.
Explanation
Scientists first directly detected gravitational waves in 2015 using LIGO, and NASA Space Place identifies LIGO as the very sensitive instrument used for that detection. The detected waves came from two black holes crashing into one another; NASA explains that the collision happened 130 crore years ago and that the ripples reached Earth in 2015. LIGO detected gravitational waves produced by merging black holes. Gravitational waves squeeze and stretch space as they pass Earth, and LIGO uses lasers, mirrors and extremely sensitive instruments to detect those tiny changes in its long arms.
Why the other options are wrong
- (A) Hubble Space Telescope observes electromagnetic radiation, whereas the first direct detection of gravitational waves in 2015 used LIGO.
- (C) ISRO is a space agency, not the observatory used as the instrument for the first 2015 detection of gravitational waves.
- (D) CERN is associated with particle physics, while LIGO was the instrument used to detect gravitational waves in 2015.
Concept
RAS Science and Technology covers major scientific discoveries and the instruments behind them. Gravitational waves link basic physics, black-hole mergers and contemporary observatory-based science.