February, 14th, 2025
NASA’s Webb Telescope to Study Asteroid 2024 YR4 as Impact Risk Increases
Topline
NASA’s James Webb Space Telescope will analyze asteroid 2024 YR4 to determine its size, composition, and potential impact risk, as astronomers monitor the rising probability of a collision with Earth in 2032.
Key Facts
- Impact Risk: Astronomers estimate a 2.3% chance that asteroid 2024 YR4 could strike Earth on December 22, 2032, up from an initial 1.3% risk. More precise calculations will be available by May, with a near-miss remaining the most likely outcome.
- Projected Impact Zone: If it were to hit, potential impact areas include the eastern Pacific Ocean, northern South America, the Atlantic Ocean, Africa, the Arabian Sea, and South Asia, according to the International Asteroid Warning Network (IAWN), which issued a warning on January 29, 2025.
- Monitoring Status: 2024 YR4 is currently the top object on NASA’s Sentry list of near-Earth objects with potential future impact risks. It also holds a level 3 ranking on the Torino Impact Hazard Scale, indicating a need for further monitoring.
- Estimated Size & Composition: The asteroid is estimated to be 130 to 300 feet (40 to 90 meters) in diameter, but this is based on brightness observations. Scientists have yet to confirm its density, composition, or potential impact damage.
What the Webb Telescope Will Do
- NASA will use Webb’s Mid-Infrared Instrument (MIRI) to measure the asteroid’s infrared heat emissions, helping refine estimates of its exact size, density, and material composition.
- Observations will take place in early March, with a second round scheduled for May before the asteroid moves beyond the reach of ground-based telescopes until June 2028.
- Webb will devote four hours of “director’s discretionary time” to study 2024 YR4, squeezing in observations between its regular science work at the request of an international team of astronomers.
Calculating the Asteroid’s Path
- Short Observation Window: Since 2024 YR4 was only discovered in late December 2024, scientists have a limited observation arc to determine its precise trajectory.
- Webb’s Extended Tracking: “The more time we track an asteroid, the better we can predict its path,” said Lord Dover, senior technical officer at the University of Hertfordshire’s Bayfordbury Observatory. “Webb will extend the observation arc by a month, improving accuracy in determining whether it will actually hit Earth.”
Why Observations Are Urgent
- The asteroid is rapidly moving away from Earth and getting dimmer each night. By the end of March, ground-based telescopes will struggle to detect it, and by April, it will require multiple nights of observation to confirm its position.
- Full Moon Interference: The recent full moon has made it harder for astronomers to track the asteroid with optical telescopes.
Key Background
- Asteroid 2024 YR4 is classified as an Apollo-type near-Earth asteroid, meaning it orbits the Sun and periodically crosses Earth’s orbit.
- On December 25, 2024, it passed 515,000 miles (828,800 km) from Earth, about twice the distance of the Moon.
- It was first detected by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) on December 27, 2024.
- Its next close approach to Earth is expected on December 17, 2028, but it will be much farther away at 4.7 million miles (7.5 million km).
- Radar observations won’t be possible until 2032, just months before its potential impact, making observations in the coming months crucial for refining risk assessments.
NASA and astronomers worldwide will closely monitor 2024 YR4, with further updates expected as new data is gathered.