Astronomers analyzing archival images from
JWST have discovered an unexpectedly vast population of the smallest asteroids ever seen in the asteroid belt between Mars and Jupiter.
© Ella Maru and Julien de WitAn artist's illustration of the James Webb Space Telescope revealing a population of small main-belt asteroids.
Astronomers analyzing archival images from the
James Webb Space Telescope (
JWST) have
discovered an unexpectedly vast population of the smallest asteroids ever seen in the asteroid belt between Mars and Jupiter. The finding could lead to better tracking of the tiny but powerful space rocks that are likely to approach Earth.
The newfound asteroids range in size from that of a bus to several stadiums — tiny compared to the massive space rock that wiped out most dinosaurs, but they nevertheless pack a significant punch. Only a decade ago an asteroid just tens of meters in size
took everyone by surprise when it exploded over Chelyabinsk, Russia, and released 30 times more energy than the atomic bomb detonated over Hiroshima in WWII.
These so-called "decameter" asteroids collide with Earth 10,000 times more frequently than their larger counterparts, but their small size makes it challenging for surveys to detect them well in advance.
In recent years, a team of astronomers including
Julien de Wit, an associate professor of planetary science at MIT, has been
testing a computationally-intensive method to identify passing asteroids in
telescope images of faraway stars.
By applying this method to thousands of JWST images of the host star in about 40 light-years distant TRAPPIST-1 system, which is the best-studied planetary system beyond our own, the researchers found eight previously known and 138 new decameter asteroids in the main asteroid belt. Among them, six appear to have been gravitationally nudged by nearby planets into trajectories that will bring them close to Earth. An early, unedited release of the findings was published Dec. 9 in the journal
Nature.
"We thought we would just detect a few new objects, but we detected so many more than expected — especially small ones," de Wit said in a
statement. "It is a sign that we are probing a new population regime."
