Why a Bus-Size Asteroid Near Earth Is Still a Planetary Defense Lesson
Why is a 29-foot asteroid being tracked when it is far too small to pose any danger to the planet? The answer is not about danger; it is about being prepared. NASA is tracking 2026 FB4, a bus-sized asteroid that is flying past Earth at a distance of about 404,000 miles. This is an example of how planetary defense works. This is part of the regular traffic in the inner solar system. This is the visible tip of a much larger problem.
2026 FB4 is a relatively small asteroid. This is important. NASA’s own framework for assessing danger is that dramatic headlines do not necessarily equate to danger. In fact, many small asteroids burn up in the atmosphere and do not cause damage. On the Torino scale’s Level 0, this is an object that is either extremely unlikely to hit the planet or is too small to cause damage if it does hit. This is part of the information that is missing when we read about an asteroid’s close pass. The problem is that this is not a trivial task.
The near-Earth objects are located through a global network of surveys, follow-up observations, and orbit calculations. According to NASA, The system is an open data initiative in which observatories around the world contribute data, which can be verified and improved by anyone in the planetary science community. If an object looks interesting enough, NASA’s Center for Near-Earth Object Studies makes increasingly precise calculations. The Minor Planet Center verifies observations. As James “Gerbs” Bauer, a researcher at the University of Maryland, explains in a NASA overview of how the system works, “The planetary defense community realizes the value of making data products available to everyone.” The system has just been demonstrated in action in the brief time in which asteroid 2024 YR4 was thought to be headed for an impact, only to be determined by additional data to be less likely.
The real issue is not with the bus-sized asteroid making its way past us today, but with all the others yet unknown. According to NASA’s Near-Earth Object Surveyor mission page, NASA’s planned infrared space observatory is being designed to find and characterize most hazardous asteroids and comets that come within 30 million miles of Earth’s orbit. The five-year baseline survey is designed to find at least two-thirds of near-Earth objects greater than 140 meters in size, which is the size range for major regional damage. These are the objects planetary defense experts are most concerned with.
The tiny near-Earth objects like 2026 FB4, which is only one meter in diameter, are not in that class. The distinction between them was further demonstrated by NASA’s DART mission in 2022. The DART mission demonstrated how to deflect an asteroid by impacting it and changing its orbit around another asteroid. According to NASA, The impact altered the asteroid’s orbit by 33 minutes, turning asteroid defense from theory into reality. The takeaway from this is not that all near-Earth objects can be deflected, but that they can be deflected in time.
The small ones are still relevant in a scientific or operational sense. They can help fine-tune detection algorithms, validate detection speed, and serve as a reminder to observers that our planet is in a densely populated orbital environment. One recent example mentioned in local media was the passage of 2026 EG1 at a distance less than the moon, with no threat whatsoever. This, however, is not unique. The differentiators are size, certainty, and warning lead-time potential.
