Scientists at MIT have achieved a groundbreaking discovery by developing a method to detect the smallest known asteroids in the main asteroid belt—a vast region between Mars and Jupiter teeming with millions of space rocks. Using advanced image-processing techniques and data from powerful telescopes, the researchers have identified over 100 previously undetected asteroids, some as small as 10 meters across.
Until now, the smallest asteroids observed in the main belt were roughly one kilometer in size. This new approach allows researchers to identify much smaller asteroids, comparable in size to buses or stadiums. Their findings, published in the journal Nature, open the door to studying these tiny objects in greater detail and tracking their potential paths toward Earth.
Mining the Skies with Shift-and-Stack Techniques
The study’s lead author, Artem Burdanov, a research scientist in MIT’s Department of Earth, Atmospheric, and Planetary Sciences, highlighted the importance of spotting small asteroids early.
“We have been able to detect near-Earth objects down to 10 meters in size when they are really close to Earth,” said Burdanov. “Now, we can spot these small asteroids when they are much farther away, enabling precise orbital tracking, which is crucial for planetary defense.”
Smaller asteroids, often called “decameter” asteroids, are much more common than the colossal ones that caused events like the extinction of the dinosaurs. Though these smaller objects rarely pose a global threat, they can cause significant regional damage, such as the 1908 Tunguska event in Siberia or the 2013 Chelyabinsk explosion over Russia.
The MIT team repurposed an image-processing method known as “shift and stack,” originally developed in the 1990s, to search for faint objects in telescope images. By aligning and stacking multiple images of the same region of space, the researchers could amplify the faint signatures of small asteroids, making them visible amidst the background noise.
This innovative approach required immense computational power. Several years ago, the team, including Burdanov, planetary science professor Julien de Wit, and graduate student Samantha Hassler, leveraged modern graphics processing units (GPUs) to efficiently process the massive datasets.
The researchers initially tested the method on data from ground-based telescopes in the SPECULOOS project, which searches for exoplanets around nearby stars. Encouraged by their success, they applied the technique to images from NASA’s James Webb Space Telescope (JWST), the world’s most powerful observatory.
A Treasure Trove of Discoveries
The team analyzed over 10,000 JWST images of the TRAPPIST-1 star system, originally collected to study distant planets. They identified eight previously known asteroids and discovered 138 new ones in the main belt, with sizes ranging from tens of meters to a few hundred meters. These are the smallest main-belt asteroids ever detected.
Asteroids are particularly bright in infrared wavelengths, making JWST’s advanced infrared capabilities ideal for this work. Among the newfound asteroids, the researchers suspect a few are on trajectories that could bring them closer to Earth in the future, while one may be a “Trojan” asteroid—an object that trails behind Jupiter in its orbit.
A New Window into Asteroid Formation
This discovery sheds light on a previously unexplored population of small asteroids, which scientists believe are created through collisions that break larger objects into smaller fragments.
“We thought we would just detect a few new objects, but we found so many more than expected, especially small ones,” said de Wit. “This indicates we’re entering a new population regime.”
The findings have significant implications for understanding the origins of meteorites and the processes shaping the solar system. By studying these smaller asteroids, scientists hope to learn more about their composition, evolution, and potential role in delivering organic materials to early Earth.
The MIT team envisions their approach being used to monitor asteroids that may one day approach Earth, enhancing efforts in planetary defense. Their work also highlights the potential of reanalyzing astronomical data with fresh perspectives.
“This is a totally new, unexplored space we are entering, thanks to modern technologies,” Burdanov said. “It’s a reminder of how much we can achieve when we look at data differently. Sometimes, the payoff is extraordinary.”
As technology advances, the ability to track and study even the tiniest space rocks promises to deepen our understanding of the solar system and bolster Earth’s defenses against potential asteroid impacts.
