Mains Previous Year Questions

Introduction

Asteroids are rocky, airless remnants left over from the formation of the solar system about 4.6 billion years ago. They mostly orbit the Sun between Mars and Jupiter in the Asteroid Belt, though some—called Near-Earth Objects (NEOs)—cross Earth’s orbital path. While most asteroids are harmless, their potential collision with Earth poses a significant natural hazard.

Body

The Threat of Asteroids

1.     Past Extinction Event:

o   The most famous example is the Cretaceous–Paleogene (K–Pg) extinction event about 66 million years ago, where an asteroid ~10 km in diameter struck the Yucatán Peninsula, causing the extinction of the dinosaurs and ~75% of Earth’s species.

2.     Present Risk:

o   While large asteroid impacts are rare, even smaller ones can cause regional devastation.

o   NASA and ESA identify thousands of Near-Earth Asteroids (NEAs) annually.

o   According to NASA’s Planetary Defense Coordination Office, objects >140 meters in size can cause regional catastrophe, while those >1 km can cause global destruction.

3.     Probability:

o   The chance of a civilization-ending asteroid impact in any given century is extremely low, but the consequences are so severe that the threat cannot be ignored.

Strategies to Prevent Asteroid Catastrophe

1. Detection and Monitoring

• NASA’s Near-Earth Object Observations Program and the Planetary Defense Coordination Office (PDCO) track and catalog potentially hazardous objects.
• ESA’s Flyeye telescope project enhances sky surveys.
• ISRO plans collaboration in international asteroid monitoring.

2. Deflection Missions

• Kinetic Impactor Method: NASA’s DART Mission (2022) successfully demonstrated asteroid deflection by crashing a spacecraft into Dimorphos, altering its orbit.
• Gravity Tractor: Using the steady gravitational pull of a spacecraft over time to change an asteroid’s trajectory.
• Nuclear Detonation: Considered as a last resort to fragment or deflect a large incoming asteroid.

3. International Cooperation

• United Nations Office for Outer Space Affairs (UNOOSA) has established the International Asteroid Warning Network (IAWN) and Space Mission Planning Advisory Group (SMPAG) for global coordination.
• Collaboration between NASA, ESA, JAXA, ISRO, and other agencies ensures joint monitoring and response strategies.

Conclusion

Asteroids represent both a scientific opportunity and a natural threat. Though the probability of a catastrophic collision is small, the potential consequences—global climate disruption, mass extinction, and destruction of ecosystems—make preparedness essential. The progress in early detection, deflection technology, and international cooperation indicates that humanity is better prepared today than ever before to face this cosmic hazard.