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.
The question has 3 parts — 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 orbiting in the main belt between Mars and Jupiter.
Cover
- Near-Earth objects: some asteroids' orbits bring them close to Earth; large ones are tracked because impacts, though rare, are catastrophic.
- Evidence: the Chicxulub impact about 66 million years ago is linked to the dinosaurs' extinction; Tunguska (1908) and Chelyabinsk (2013) show smaller threats.
- Real risk: extinction-level impacts are very low-probability but high-consequence; city-destroying impacts are more likely and less tracked.
- Detection: sky surveys and tracking, NASA's Planetary Defense Coordination Office, ESA programmes, ISRO's NETRA for space objects.
- Deflection: NASA's DART (2022) altered the orbit of Dimorphos — a successful kinetic-impactor test; gravity tractor and nuclear options studied.
- Global coordination: UN-endorsed International Asteroid Warning Network and Space Mission Planning Advisory Group.
Close with · The threat is remote but real; early detection, tested deflection and international cooperation turn a natural catastrophe into a manageable risk.
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.”
Question: UPSC's CS (Main) 2024, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 281 words (UPSC limit 250) · Minimalist IAS
Asteroids are rocky or metallic remnants of the solar system's formation, most orbiting in the main belt between Mars and Jupiter; those whose orbits bring them close to Earth are tracked as near-Earth objects (NEOs).
What asteroids are
- They range from metres to hundreds of kilometres across and are classed by composition — carbonaceous, silicate or metallic; NEOs that pass within 0.05 AU of Earth's orbit and exceed about 140 m are termed potentially hazardous.
How real is the threat
- Evidence: the Chicxulub impact about 66 million years ago is linked to the dinosaurs' extinction; Tunguska (1908) flattened forest, and Chelyabinsk (2013) injured over a thousand people from a body only about 20 m wide.
- Probability: extinction-level impacts by kilometre-scale bodies are extremely rare, and most such objects are already catalogued with none on a collision course; city-destroying impacts by smaller bodies are more frequent and less completely tracked.
- Assessment: the threat is remote in any human lifetime but non-zero and irreversible, which justifies steady, low-cost preparation.
Strategies for prevention
- Detection: ground surveys and space telescopes, NASA's Planetary Defense Coordination Office, ESA programmes and ISRO's NETRA for tracking space objects.
- Deflection: NASA's DART (2022) struck Dimorphos and shortened its orbit by 32 minutes — the first kinetic-impactor test; ESA's Hera follows up, while gravity tractors and nuclear stand-off options are studied for larger bodies.
- Coordination: the UN-endorsed International Asteroid Warning Network and Space Mission Planning Advisory Group; the 2029 close approach of Apophis is a planned observation opportunity.
- Civil preparedness: impact-effects modelling and evacuation plans for small objects detected late.
The threat is remote but real; early detection, tested deflection and international cooperation turn a natural catastrophe into a manageable risk.
Written by Minimalist IAS from facts checked at source (how we verify) — a little fuller than exam length, so every part of the question is covered; in the hall, keep the structure and trim the detail. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.