What are asteroids? How real is the threat of them causing extinction of life? What strategies have been developed to prevent such a catastrophe?
Approach · directive: “what / how real”
What it asks · Define asteroids, assess the realistic risk of an extinction-level impact, and describe detection and deflection strategies.
It asks 3 things — answer each
- What are asteroids: definition, origin and near-Earth objects
- How real is the threat of an extinction-level impact: evidence, probability and a clear assessment
- What strategies have been developed to prevent such a catastrophe: detection, deflection and coordination
Open with · Asteroids are rocky or metallic remnants of the solar system's formation, most in the main belt between Mars and Jupiter; over 36,000 near-Earth asteroids have been discovered (NASA CNEOS, via the UN).
Cover
- Near-Earth objects: NEOs within 0.05 AU of Earth's orbit and larger than about 140 m are potentially hazardous.
- Evidence: Chicxulub about 66 million years ago; Tunguska, 30 June 1908; Chelyabinsk, 15 February 2013, a 20 m object never seen before entry.
- Real risk: extinction-level impacts are very low-probability but irreversible; city-destroying impacts are likelier and less tracked.
- Detection: sky surveys, NASA's Planetary Defense Coordination Office, ESA programmes, ISRO's NETRA.
- Deflection: DART (2022) shortened Dimorphos' orbit by 32 minutes; ESA's Hera follows up; gravity tractor and nuclear options studied.
- Coordination: IAWN and SMPAG (2014) under COPUOS; 30 June is International Asteroid Day; Apophis passes 32,000 km from Earth on 13 April 2029.
Close with · Planetary defence is the one natural disaster humanity can prevent in advance; detection, tested deflection and the IAWN–SMPAG system, rehearsed on Apophis in 2029, make an extinction risk a managed one.
Add value (verified)
- The UN notes that near-Earth objects within 0.05 AU of Earth's orbit and larger than about 140 m are potentially catastrophic threats.United Nations — International Asteroid Day ↗“NEOs, that are closer than 0.05 astronomical units to Earth's orbit (about 7.5 million kilometers) and larger than about 140 meters in size, represent potentially catastrophic threats to our planet.”
- NASA confirmed that DART's impact shortened Dimorphos' orbit around Didymos by 32 minutes (from 11 h 55 min to 11 h 23 min).NASA — NASA Confirms DART Mission Impact Changed Asteroid's Motion in Space (11 October 2022) ↗“the investigation team has confirmed the spacecraft's impact altered Dimorphos' orbit around Didymos by 32 minutes, shortening the 11 hour and 55-minute orbit to 11 hours and 23 minutes.”
- Over 36,000 near-Earth asteroids have been discovered (NASA Center for NEO Studies, cited by the UN).United Nations — International Asteroid Day, 30 June ↗“According to NASA’s Center for NEO Studies, there are over 36,000 Near Earth Asteroids discovered”
- The UN General Assembly declared 30 June International Asteroid Day, the anniversary of the Tunguska impact of 1908.United Nations — International Asteroid Day, 30 June ↗“declaring 30 June International Asteroid Day in order to "observe each year at the international level the anniversary of the Tunguska impact over Siberia, Russian Federation, on 30 June 1908”
- IAWN and SMPAG were established in 2014 after COPUOS endorsement in 2013.United Nations — International Asteroid Day, 30 June ↗“the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG) were established in 2014.”
- Chelyabinsk, 15 February 2013: an approximately 20 m, 13,000-tonne, previously unknown near-Earth object entered the atmosphere over the city.ESA — Chelyabinsk asteroid (image and caption, 2017) ↗“an approximately 20 m-diameter, 13 000-tonne (and previously unknown) near-Earth object (NEO) entered Earth's atmosphere over the city of Chelyabinsk in Russia.”
- Apophis will safely pass about 32,000 km from Earth on 13 April 2029.NASA Science — Asteroid Apophis ↗“Near-Earth asteroid Apophis is a potentially hazardous asteroid that will safely pass close to Earth on April 13, 2029. It will come about 20,000 miles (32,000 kilometers) from our planet’s surface”
Question: UPSC's CS (Main) 2024, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 3 Oct 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer· 365words · Minimalist IAS
Asteroids are rocky or metallic remnants of the solar system's formation, most orbiting in the main belt between Mars and Jupiter. More than 36,000 near-Earth asteroids have been discovered (NASA's Center for NEO Studies). A few of these cross Earth's path, which is why the question of extinction is asked at all.
What asteroids are
- Size and type: from metres to hundreds of kilometres across; carbonaceous, silicate or metallic by composition.
- Near-Earth objects: those passing within 0.05 AU of Earth's orbit and larger than about 140 m are classed potentially hazardous.
How real is the threat of extinction
- Evidence: the Chicxulub impact about 66 million years ago is linked to the dinosaurs' extinction; Tunguska on 30 June 1908 flattened Siberian forest; Chelyabinsk on 15 February 2013 was a 20 m, 13,000-tonne object, previously unknown, that exploded over a city.
- Probability: kilometre-scale, extinction-class impacts are extremely rare and most such bodies are catalogued with none on a collision course; city-destroying impacts by smaller bodies are more frequent and less completely tracked.
- Assessment: remote in any human lifetime but non-zero and irreversible, which justifies steady, low-cost preparation.
Strategies developed to prevent a catastrophe
- Detect: surveys, PDCO, NETRA
- Track and characterise
- Warn: IAWN
- Plan: SMPAG
- Deflect: kinetic impactor
- Detection: ground surveys and space telescopes, NASA's Planetary Defense Coordination Office, ESA programmes and ISRO's NETRA for tracking space objects.
- Deflection tested: NASA's DART (2022) struck Dimorphos and shortened its orbit by 32 minutes, humanity's first deliberate change to a celestial body's motion; ESA's Hera follows up, while gravity tractors and nuclear stand-off options are studied for larger bodies.
- Coordination: the UN-endorsed IAWN and SMPAG, set up in 2014 after COPUOS approval; 30 June, the Tunguska anniversary, is International Asteroid Day.
- Rehearsal ahead: Apophis will pass about 32,000 km from Earth on 13 April 2029, closer than geosynchronous satellites, a planned observation opportunity.
- Civil preparedness: impact-effects modelling and evacuation plans for small objects detected late.
Planetary defence is the one natural disaster humanity can prevent in advance. Detection, a tested deflection method and the IAWN–SMPAG system, rehearsed on Apophis in 2029, turn an extinction risk into a managed one; an impact respects no border, so the effort must stay global.
Prepared by Minimalist IAS to the answer standard of Shivam Singh (mentor, 7 years) · facts checked against official sources (how we verify) · updated 3 Oct 2026. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.
