Nasa says asteroid 2024 YR4 impact risk rises to 3.1%, potential threat

Express Tribune

19-02-2025

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A newly identified asteroid, 2024 YR4, has been classified as the most threatening space rock ever recorded by modern forecasting, with NASA data estimating a 3.1% chance of impact on December 22, 2032.
The asteroid's trajectory could take it over some of the world's most populous cities, raising concerns among astronomers and planetary defense agencies.
The estimated impact corridor stretches from the eastern Pacific Ocean, across South America, the Atlantic, Africa, the Middle East, and into South Asia.
This trajectory includes eight of the world's top 100 most populated cities — Bogotá, Abidjan, Lagos, Khartoum, Mumbai, Kolkata, and Dhaka—with a combined urban population of over 110 million people.
Asteroid's Destructive Potential
Measuring between 130 and 300 feet (40–90 metres) wide, 2024 YR4 has the potential to cause massive destruction if it enters Earth's atmosphere. Scientists estimate its impact force at approximately eight megatons of TNT—more than 500 times the power of the Hiroshima atomic bomb.
If the asteroid collides with Earth, the most likely scenario is an airburst explosion at high altitude, which could devastate an area with a 50-kilometer (30-mile) radius. However, if it is at the larger end of size estimates, it could create an impact crater, further escalating its destructive power.
The asteroid's speed, which could reach 40,000 miles per hour, would significantly amplify its potential for devastation.
NASA and Global Response Efforts
Despite the historically high impact probability, experts emphasize that there is no immediate cause for panic. The International Asteroid Warning Network (IAWN), a United Nations-endorsed planetary defense coalition, has been closely monitoring the asteroid since its detection by Chile's El Sauce Observatory on December 27, 2023.
On January 29, 2024, IAWN issued an official warning after the impact probability surpassed 1%, a rare event in planetary defense history. The European Space Agency's planetary defense office has independently estimated the impact risk at 2.8%, slightly lower than NASA's calculation.
'This is not a crisis at this point in time,' said Richard Moissl, head of ESA's planetary defense office. 'This is not the dinosaur killer. This is not a planet killer. This is, at most, dangerous for a city.'
Upcoming James Webb observations & ongoing monitoring
NASA and other space agencies are working to refine 2024 YR4's trajectory. In March 2025, NASA's James Webb Space Telescope (JWST)—the most powerful space observatory—will be tasked with closely studying the asteroid's size, composition, and trajectory.
'Webb is able to see things that are very, very dim,' said Bruce Betts, chief scientist of the Planetary Society. 'That's key because the asteroid's orbit is currently taking it out toward Jupiter, making observations challenging until its next close approach in 2028.'
Ground-based telescopes will continue tracking the asteroid until April 2024, after which it will become too faint to observe. It will remain out of sight until June 2028, when astronomers will get another opportunity to refine its trajectory.
Mitigation plans: DART & future deflection missions
NASA has reassured the public that the global scientific community has the time and technology to act if 2024 YR4's impact risk rises. In 2022, NASA successfully tested its Double Asteroid Redirection Test (DART) mission, demonstrating that a spacecraft could alter an asteroid's course.
China has announced it will conduct its own asteroid-deflection test in 2027, targeting a smaller asteroid to evaluate redirection techniques. Other space agencies are also exploring contingency measures, including gravity tractors, laser ablation, and nuclear deflection as a last resort.
Moissl explained that if the risk probability exceeds 10%, IAWN would issue a formal global alert, prompting UN member states with territories in potential impact zones to begin emergency preparedness planning.
Historical Comparison: Apophis 2004 & the dinosaur extinction
The last time an asteroid posed a similar risk was Apophis in 2004, which initially had a 2.7% chance of striking Earth in 2029. However, further observations ruled out the possibility of impact.
Unlike the six-mile-wide asteroid that wiped out the dinosaurs 66 million years ago, 2024 YR4 is classified as a 'city killer', rather than a global extinction event.
No immediate danger, but continued monitoring required
Scientists stress that while the asteroid's impact odds remain low, its trajectory is being closely monitored. If future observations indicate an increased risk, planetary defense agencies will have time to take necessary action.
For now, experts advise against alarm. 'Naturally, when you see the percentages go up, it doesn't make you feel warm and fuzzy,' said Betts, 'but as astronomers gather more data, the probability will likely edge up before rapidly dropping to zero.'