Discovery and Classification
- Asteroid 2024 YR4 was discovered in December 2024 using the ATLAS telescope in Chile.
- Classified as a near-Earth asteroid (NEA) — orbits within 1.3 AU of the Sun.
- Initially feared as a threat to Earth; prompted NASA’s highest-ever asteroid alert in February 2025.
Relevance : GS 3(Science ,Technology)
Impact Risk Analysis
- Early estimate: 3.1% chance of Earth impact in 2032.
- Latest data: Negligible chance of Earth impact, but 3.8% chance of hitting the Moon on 22 December 2032.
- Size: Estimated 65 meters wide — not large enough to be a “potentially hazardous object” (which requires >140 m width).
Trajectory Tracking and Modelling
- Asteroid orbits determined using:
- Ground-based visible light telescopes.
- Infrared observations from James Webb Space Telescope.
- Orbital models are refined with more data to improve impact predictions.
- NASA uses the Torino Scale for threat assessment — YR4 was at Level 3, now downgraded.
Potential Moon Impact
- If YR4 hits the Moon:
- Expected crater size: 500 to 2,000 metres.
- Explosion would release energy 340 times greater than the Hiroshima bomb.
- Moon’s orbit will remain unaffected.
Visibility and Scientific Value
- Impact flash may or may not be visible from Earth — depends on Moon’s brightness and impact location.
- Could yield valuable data on lunar regolith and surface composition.
- Spacecraft like Chandrayaan-2 could capture the event.
Broader Implications
- Asteroids remain an ongoing threat — e.g., the 2013 Chelyabinsk meteor caused serious damage.
- Larger impacts could induce climate change by injecting dust into Earth’s atmosphere.
- However, asteroid impacts are preventable with early detection and tracking — offering hope for planetary defense.
