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The International Asteroid Warning Network (IAWN) is a global collaboration dedicated to detecting, tracking, and assessing near-Earth objects (NEOs) that could pose a risk to the planet. Established following United Nations recommendations, the network consists of observatories, space agencies, and research institutions that share data and conduct impact probability calculations. When a detected asteroid meets certain risk thresholds, IAWN issues alerts to international organizations, including the United Nations Office for Outer Space Affairs (UNOOSA) and the Space Mission Planning Advisory Group (SMPAG), which coordinate possible response strategies.
Asteroid 2024 YR4 was first detected on December 27, 2024, by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) station operated by the University of Hawai’i in Chile. Subsequent observations confirmed its trajectory, and archival images from December 25 and 26 provided additional data points. With a size estimated between 40 and 90 meters (130–300 feet), the asteroid falls within the category of objects that could cause significant localized damage if an impact were to occur.
Initial calculations by NASA’s Center for Near-Earth Object Studies (CNEOS) and the European Space Agency’s Near-Earth Object Coordination Centre (NEOCC) place the probability of impact at 1.3% for December 22, 2032. This means there is a 98.7% chance the asteroid will pass by Earth without incident. While the likelihood of impact remains low, the uncertainty surrounding the asteroid’s orbit justifies continued monitoring.
If 2024 YR4 were to impact Earth, the potential impact zone spans a broad corridor, including the eastern Pacific Ocean, northern South America, the Atlantic Ocean, Africa, the Arabian Sea, and South Asia. This range reflects uncertainties in the asteroid’s trajectory, which will be refined with further observations.
In the event of an impact, the level of destruction would depend on the asteroid’s size and the location of the collision. If the object is closer to the upper estimate of 90 meters, the resulting explosion could generate a blast radius extending up to 50 kilometers from the point of impact. This could cause severe damage to infrastructure and pose risks to human populations in affected areas. If the asteroid were to land in the ocean, the primary concern would be atmospheric shock waves rather than a tsunami, given the relatively small size of the object.
Observatories will continue to monitor 2024 YR4 through early April 2025. At that point, it will move beyond the reach of Earth-based telescopes and will not be observable again until June 2028, when it returns to a position closer to Earth. The next period of observation will provide improved trajectory predictions, potentially raising or lowering the estimated probability of impact.
By the time the 2025 observation window closes, impact probability estimates could shift in two directions. The probability might increase significantly if new data suggests a trajectory closer to Earth. It could also decrease below the 1% threshold, eliminating the need for continued high-priority tracking.
While the probability of impact remains low, organizations responsible for planetary defense are taking a measured approach. IAWN and its partner institutions will continue refining calculations and updating international agencies as new data becomes available. Possible response options include further tracking and analysis to refine impact risk assessments and provide a clearer picture of the asteroid’s trajectory. If the risk increases, planetary defense groups may consider mitigation strategies such as kinetic impactors or gravity tractors. Governments and emergency response agencies in potential impact zones will be informed so that they can develop contingency plans.
Asteroid 2024 YR4 is a newly detected near-Earth object with a small chance of impacting Earth on December 22, 2032. Current estimates suggest a 1.3% probability of collision, with a wide impact corridor spanning multiple continents and ocean regions. While the likelihood of impact is low, continued monitoring is essential to refine trajectory models. Observations will resume in 2028, at which point more precise calculations will determine if further action is necessary. In the meantime, international agencies remain vigilant, prepared to respond if the risk level changes.
10 Best Selling Books About Asteroids
Asteroid Hunters by Carrie Nugent
This concise nonfiction book explains how scientists and survey programs find and track near-Earth asteroids, using real detection methods, data pipelines, and follow-up observations. It also describes why asteroid discovery supports planetary defense decision-making and long-term monitoring of potential impact risks.
How to Kill an Asteroid: The Real Science of Planetary Defense by Robin George Andrews
This nonfiction narrative describes how modern planetary defense works, including detection, orbit prediction, and deflection concepts that are used to reduce asteroid impact risk. It connects these methods to mission planning, engineering constraints, and the practical realities of responding to a hazardous near-Earth object.
Fire in the Sky: Cosmic Collisions, Killer Asteroids, and the Race to Defend Earth by Gordon L. Dillow
This nonfiction account outlines the history of major impact events and the scientific evidence that supports modern impact-hazard estimates. It also explains how asteroid surveys, risk modeling, and response planning shape current planetary defense policy and technology choices.
Catching Stardust: Comets, Asteroids and the Birth of the Solar System by Natalie Starkey
This nonfiction book explains what meteorites and asteroid samples reveal about early solar system chemistry, planetary formation, and the origins of water and organics. It links laboratory techniques and space missions to the broader field of asteroid science for general readers.
Asteroids by Clifford J. Cunningham
This nonfiction overview summarizes how asteroids were discovered, how their orbits are measured, and how asteroid populations are classified and studied over time. It also explains how cultural interest in asteroids has tracked alongside advances in observation, missions, and impact-risk awareness.
Cosmic Impact: Understanding the Threat to Earth from Asteroids and Comets by Andrew May
This nonfiction book explains the physical processes behind impacts, including entry dynamics, blast effects, and the role of size and speed in determining damage outcomes. It also presents how scientists estimate frequencies and build impact-hazard scenarios for near-Earth objects.
Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets by John S. Lewis
This nonfiction work describes the resource potential of asteroids, including metals and volatiles, and explains how in-space materials could support industrial activity beyond Earth. It also connects asteroid mining concepts to mission logistics, propulsion tradeoffs, and the economics of operating far from terrestrial supply chains.
Rain of Iron and Ice: The Very Real Threat of Comet and Asteroid Bombardment by John S. Lewis
This nonfiction book explains the geological and historical evidence for large impacts and bombardment episodes, including what crater records indicate about long-term risk. It also describes how impact science informs public risk perception and the practical case for asteroid detection and mitigation planning.
The Asteroid Threat: Defending Our Planet from Deadly Near-Earth Objects by William E. Burrows
This nonfiction book focuses on near-Earth objects, explaining how discovery shortfalls, tracking uncertainty, and communication gaps can affect real-world preparedness. It also describes the institutional and technical steps that can reduce impact risk, from survey coverage to response coordination and deflection readiness.
Bennu 3-D: Anatomy of an Asteroid by Dante S. Lauretta
This nonfiction atlas-style book presents asteroid Bennu through mission imagery and structured mapping, tying surface features to the science goals of sample-return exploration. It is coauthored by a team connected to the OSIRIS-REx effort and is designed to make asteroid geology and mission results accessible to nontechnical readers.
