Astronomers using JWST’s archival images New Asteroids have uncovered a surprisingly large population of the tiniest asteroids ever observed within the asteroid belt located between Mars and Jupiter.
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James Webb Telescope Discovers 100+ New Asteroids Between Jupiter and Mars — Some on Potential Earth-Bound Paths!
Astronomers analyzing images from the James Webb Space Telescope (JWST) have uncovered a surprisingly large population of tiny asteroids in the asteroid belt between Mars and Jupiter. This unexpected discovery may improve our ability to track these small but impactful space rocks, some of which could approach Earth.
The newly identified asteroids range in size from a bus to several stadiums—significantly smaller than the massive asteroid that wiped out most dinosaurs. However, these small asteroids still carry immense energy. For example, just a decade ago, an asteroid only tens of meters across unexpectedly exploded over Chelyabinsk, Russia, unleashing energy equivalent to 30 times the atomic bomb dropped on Hiroshima during World War II.
These so-called “decameter” asteroids collide with Earth 10,000 times more frequently New Asteroids than their larger counterparts. Yet, their small size makes them extremely difficult to detect using conventional survey methods, which limits our ability to prepare for such encounters.
To tackle this challenge, a team of astronomers led by Julien de Wit, associate professor of planetary science at MIT, has been testing an advanced, computationally demanding method to spot passing asteroids in telescope images of distant stars.
The team applied this method to thousands of JWST images of the TRAPPIST-1 system, a star system located about 40 light-years away and one of the most well-studied planetary systems beyond our own. Through this analysis, researchers identified 138 new decameter-sized asteroids within the main asteroid belt, along with eight previously known ones.
Notably, six of these asteroids appear to have been gravitationally New Asteroids nudged by nearby planets, shifting their orbits and potentially bringing them closer to Earth. This discovery highlights how even small space rocks can be influenced into Earth-crossing trajectories. The findings, though preliminary, were released on December 9 in the journal Nature.
“We expected to detect just a handful of new objects, but the sheer number—especially the smaller ones—took us by surprise,” said Julien de Wit in a statement. “This suggests we are uncovering an entirely new population of asteroids we hadn’t probed before.”
By refining these detection techniques, astronomers hope to improve asteroid monitoring and provide earlier warnings for potentially hazardous space rocks, ensuring better planetary defense for Earth.
Fresh look at archival data
For the new study, de Wit and his colleagues compiled roughly 93 hours worth of JWST images of the TRAPPIST-1 system in order to enhance faint, fast-moving objects like asteroids above the background noise.
While such an approach rarely works for objects with unknown orbits, the team bypassed the limitation by using powerful graphics processing units (GPUs) to rapidly sift through large datasets, enabling a “fully blind search” across all possible directions to locate the newly-discovered asteroids, and then stacking those images.
Scientists can now spot asteroids in the main belt as small as 10 meters across with the team's new approach. (Image credit: Ella Maru and Julien de Wit)
This is a totally new, unexplored space we are entering, thanks to modern technologies,” said Artem Burdanov, lead author and research scientist at MIT’s Earth, Atmospheric, and Planetary Sciences department. “It’s a good example of what we can do as a field when we look at the data differently — sometimes there’s a big payoff, and this is one of them.”
The newfound asteroids are the smallest ever detected in the main New Asteroids belt. These tiny space rocks are remnants of ancient collisions between larger, kilometer-sized asteroids. The James Webb Space Telescope (JWST) has proven to be the perfect tool for discovering them. Unlike traditional telescopes that rely on faint sunlight reflected off asteroid surfaces, JWST’s sharp infrared sensors detect the thermal emissions of asteroids, which glow much brighter in infrared light.
According to the researchers, JWST’s ability to spot these tiny objects marks a breakthrough in understanding the asteroid belt’s smallest population. This capability could help scientists monitor and predict the trajectories of smaller asteroids with greater precision.
Future JWST observations will be even more ambitious, with plans to observe 15 to 20 distant stars for over 500 hours. These extended observations could uncover thousands more decameter-sized asteroids within our solar system, further expanding our understanding of their prevalence and behavior.
In addition to JWST, new-generation telescopes will also play a pivotal role in uncovering small asteroids. Leading the charge is the Vera C. Rubin Observatory in Chile, which is set to begin operations next year. Equipped with the world’s largest digital camera, the observatory will photograph the southern sky every night for at least a decade. Each image will cover an area equivalent to 40 full moons. Thanks to its unprecedented frequency and resolution, the Rubin Observatory is expected to detect up to 2.4 million asteroids — almost double the current known catalog — within its first six months of operation.
“We now have a way of spotting these small asteroids when they are much farther away,” Burdanov explained. “This allows us to do more precise orbital tracking, which is absolutely key for planetary defense.”
The combination of JWST’s infrared capabilities and upcoming observatories like Vera C. Rubin will mark a new era in asteroid discovery. By identifying these small but significant objects earlier, scientists can better predict their paths, minimize risks, and strengthen Earth’s planetary defense systems.