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Recently, scientists observed the merger of giant 'blackholes' billions of light-years away from the Earth. What is the significance of this observation?
Explanation
The correct answer is option B because in 2015, The Laser Interferometer Gravitational-Wave Observatory (LIGO), USA, physically sensed the distortions in spacetime caused by passing gravitational waves generated by two colliding black holes nearly 1.3 billion light-years away[1]. Gravitational waves are 'ripples' in the fabric of spacetime caused by some of the most violent and energetic processes in the Universe, and massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt spacetime in such a way that 'waves' of distorted space would radiate from the source[2]. This observation represents the last great confirmation of Einstein's ideas[3], as Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity[2]. The detection of gravitational waves from merging black holes opened a new era of astronomy, allowing scientists to observe cosmic events that do not emit light or particles. Options A, C, and D are incorrect as there is no evidence in the sources linking black hole merger observations to Higgs boson detection, wormhole travel confirmation, or understanding singularities.
Sources- [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Gravitational Waves > p. 5
- [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Gravitational Waves > p. 4
- [3] https://www.bbc.com/news/science-environment-35523676
PROVENANCE & STUDY PATTERN
Guest previewThis question is a classic 'Nobel Prize' trigger. The LIGO discovery (announced 2016, Nobel 2017) was the decade's biggest physics news. While the provenance skeleton calls it 'borderline' due to text matching, for a serious aspirant, this was an absolute Sitter. If it wins a Nobel, you must know the 'Cause' (Merger) and the 'Effect' (Waves).
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
Web source
Presence: 5/5
"So much of what we theorise to be out there does not radiate light in any of its forms - from gamma-rays to the ultraviolet, from the visible to radio waves - or emit particles. And unlike light or particles, gravitational waves cannot"
Why this source?
- Explains that gravitational waves are signals distinct from light or particles.
- Shows the black-hole merger produced gravitational-wave signals, not particle detections like the Higgs.
Web source
Presence: 4/5
"This is all reminiscent of the Higgs boson discovery. You will recall that the detection was only claimed when (and because) two separate experiments at the Large Hadron Collider saw exactly the same thing in the data."
Why this source?
- Directly compares gravitational-wave detection with the Higgs boson discovery as an analogy, noting the Higgs was claimed from collider experiments.
- Implies that a gravitational-wave observation is not the same as detecting Higgs particles, which required particle-collider data from separate experiments.
Web source
Presence: 3/5
"If ultralight bosons exist, they can extract rotational energy from black holes: how much energy is extracted and how much the rotation of the black holes slows over time depends on the unknown mass of these particles. The observation that the massive black hole in the binary system that emitted GW241011 continues to rotate rapidly even millions or billions of years after its formation rules out a wide range of ultralight boson masses."
Why this source?
- Discusses how black-hole observations constrain hypothetical ultralight bosons by ruling out mass ranges, rather than detecting such particles.
- Shows merger observations are used to limit particle properties, not to announce discovery of particles like the Higgs.
- Explains that gravitational waves are signals distinct from light or particles.
- Shows the black-hole merger produced gravitational-wave signals, not particle detections like the Higgs.
- Directly compares gravitational-wave detection with the Higgs boson discovery as an analogy, noting the Higgs was claimed from collider experiments.
- Implies that a gravitational-wave observation is not the same as detecting Higgs particles, which required particle-collider data from separate experiments.
- Discusses how black-hole observations constrain hypothetical ultralight bosons by ruling out mass ranges, rather than detecting such particles.
- Shows merger observations are used to limit particle properties, not to announce discovery of particles like the Higgs.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > UPSC Prelims 2019] Recently, scientists observed the merger of giant 'blackholes' billions of light-years away from the earth. What is the significance of this observation? > p. 6
Strength: 5/5
“[UPSC Prelims 2019] Recently, scientists observed the merger of giant 'blackholes' billions of light-years away from the earth. What is the significance of this observation?
• a) 'Higgs boson particles' were detected.• b) 'Gravitational waves' were detected.• c) Possibility of intergalactic space travel through 'wormhole' was confirmed.• d) It enabled the scientists to understand 'singularity'.”
Why relevant
This UPSC question item explicitly contrasts two outcomes: detection of 'Higgs boson particles' versus detection of 'gravitational waves' as the significance of a distant black-hole merger.
How to extend
A student could use this contrast to suspect the merger observation most likely produced gravitational-wave signals rather than particle detections and then check how each is normally observed.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Gravitational Waves > p. 5
Strength: 5/5
“• While the processes that generate gravitational waves can be extremely violent and destructive, by the time the waves reach Earth, they are billions of times smaller. In 2015, The Laser Interferometer Gravitational-Wave Observatory (LIGO), USA, physically sensed the distortions in spacetime caused by passing gravitational waves generated by two colliding black holes nearly 1.3 billion light-years away!”
Why relevant
States that LIGO physically sensed spacetime distortions (gravitational waves) from colliding black holes about 1.3 billion light‑years away.
How to extend
A student can extend this by noting that instruments and signals for gravitational waves are specific (interferometers sensing spacetime ripples) and so different from methods that detect elementary particles.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Gravitational Waves > p. 4
Strength: 4/5
“• Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity. Gravitational waves are 'ripples' in the fabric of spacetime caused by some of the most violent and energetic processes in the Universe. (Spacetime: https://www.youtube.com/watch?v=sryrZwYguRQ)• Massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt spacetime in such a way that 'waves' of distorted space would radiate from the source (like the movement of waves away from a stone thrown into a pond). These ripples travel at the speed of light through the Universe, carrying with them information about their origins.”
Why relevant
Explains the nature of gravitational waves (ripples in spacetime produced by accelerating massive objects like orbiting black holes).
How to extend
Use the definition to infer that detected signals from a merger are spacetime ripples carrying information about the merger, not necessarily evidence of produced/observed subatomic particles like the Higgs.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Black holes > p. 15
Strength: 3/5
“• Black holes are believed to form from massive stars at the end of their lifetimes. The density of matter in a black hole cannot be measured (infinite!). The gravitational pull is so great that nothing can escape from it, not even light.• Black holes distort the space around them and can suck neighbouring matter into them including stars.”
Why relevant
Describes black holes and their violent interactions (distorting space and accreting matter), giving context for why mergers produce strong gravitational effects.
How to extend
Combine this with knowledge that such violent spacetime dynamics produce waves (not particle signatures) to argue mergers are expected to yield gravitational-wave observations rather than direct detection of specific particle types.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Explanation: > p. 7
Strength: 3/5
“• A singularity (gravitational singularity or (spacetime singularity) is a condition in which gravity is so intense that spacetime ceases to exist and our laws of physics become invalid. Singularities were first predicated as a result of Einstein's Theory of General Relativity, which resulted in the theoretical existence of black holes. • In essence, the theory also predicted that any star reaching beyond a certain point in its mass (aka. the Schwarzschild Radius) would exert a gravitational force so intense that it would collapse. At this point, nothing would be capable of escaping its surface, including light. This phenomenon is known as the Chandrasekhar Limit, named after the Indian astrophysicist Subrahmanyan Chandrasekhar, who proposed it in 1930.”
Why relevant
Defines singularity and references general relativity as the theoretical framework predicting black holes and their extreme gravity.
How to extend
A student can extend this by noting that general relativity predicts gravitational-wave phenomena around mergers, implying the primary observational signature will be gravitational (not particle) in nature.
This UPSC question item explicitly contrasts two outcomes: detection of 'Higgs boson particles' versus detection of 'gravitational waves' as the significance of a distant black-hole merger.
A student could use this contrast to suspect the merger observation most likely produced gravitational-wave signals rather than particle detections and then check how each is normally observed.
States that LIGO physically sensed spacetime distortions (gravitational waves) from colliding black holes about 1.3 billion light‑years away.
A student can extend this by noting that instruments and signals for gravitational waves are specific (interferometers sensing spacetime ripples) and so different from methods that detect elementary particles.
Explains the nature of gravitational waves (ripples in spacetime produced by accelerating massive objects like orbiting black holes).
Use the definition to infer that detected signals from a merger are spacetime ripples carrying information about the merger, not necessarily evidence of produced/observed subatomic particles like the Higgs.
Describes black holes and their violent interactions (distorting space and accreting matter), giving context for why mergers produce strong gravitational effects.
Combine this with knowledge that such violent spacetime dynamics produce waves (not particle signatures) to argue mergers are expected to yield gravitational-wave observations rather than direct detection of specific particle types.
Defines singularity and references general relativity as the theoretical framework predicting black holes and their extreme gravity.
A student can extend this by noting that general relativity predicts gravitational-wave phenomena around mergers, implying the primary observational signature will be gravitational (not particle) in nature.
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