In a fascinating repurposing of space telescope data, astronomers have pierced the veil of our solar system’s asteroid belt, revealing a previously invisible population of diminutive space rocks that could help unlock the origins of Earth-impacting meteorites. These newly discovered celestial objects, ranging from merely bus-sized to several stadiums across, represent the smallest asteroids ever detected in the main asteroid belt between Mars and Jupiter.
Published in Nature | Estimated reading time: 4 minutes
While dinosaur-killing asteroids spanning 10 kilometers – roughly the width of Brooklyn – strike Earth only once every hundred million years or so, their smaller cousins pose a more frequent challenge to our planet’s defenses. These “decameter” asteroids, measuring just tens of meters across, can unleash regional devastation when they intersect with Earth’s path, as demonstrated by the 1908 Tunguska event and the 2013 Chelyabinsk meteor.
Using NASA’s James Webb Space Telescope’s superior infrared capabilities, MIT researchers have identified 138 previously unknown asteroids in the main belt, all measuring less than a kilometer in diameter. This achievement marks a significant improvement over previous detection capabilities, which were limited to asteroids roughly a kilometer or larger in size.
“We thought we would just detect a few new objects, but we detected so many more than expected, especially small ones,” says Julien de Wit, a professor of planetary science at MIT and study co-author. “It is a sign that we are probing a new population regime, where many more small objects are formed through cascades of collisions that are very efficient at breaking down asteroids below roughly 100 meters.”
The discovery emerged from an innovative recycling of data initially collected for exoplanet research. The team, led by research scientist Artem Burdanov, applied a technique called “shift and stack” to thousands of JWST images originally taken to study the TRAPPIST-1 planetary system. This method, combined with state-of-the-art graphics processing units, allowed them to detect faint objects that would otherwise remain hidden in the noise of space observations.
Glossary
- Decameter asteroids: Space rocks measuring tens of meters in diameter, significantly smaller than kilometer-sized asteroids but capable of causing regional damage upon Earth impact.
- Main asteroid belt: A region between Mars and Jupiter where millions of asteroids orbit the Sun.
- Shift and stack: An image processing technique that combines multiple telescope images to reveal faint objects that would otherwise be invisible in individual frames.
Test Your Knowledge
What is the approximate width of the asteroid that caused the extinction of dinosaurs?
The dinosaur-extinction asteroid was approximately 10 kilometers wide, about the width of Brooklyn.
Why are decameter asteroids particularly important to study?
These smaller asteroids can strike Earth more frequently (every few years) and can cause significant regional damage, as demonstrated by the Tunguska and Chelyabinsk events.
How did the researchers manage to detect such small asteroids in the main belt?
They used the James Webb Space Telescope’s infrared capabilities combined with a “shift and stack” image processing technique, applied to thousands of images originally taken for studying the TRAPPIST-1 system.
What makes the James Webb Space Telescope particularly effective for detecting small asteroids in the main belt?
Asteroids in the main asteroid belt are much brighter at infrared wavelengths than at visible wavelengths, making JWST’s infrared capabilities especially useful for detection.
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