The James Webb Space Telescope (JWST), renowned for its deep space observations, has expanded its scope to include the study of asteroids, uncovering a surprising discovery in the main asteroid belt between Mars and Jupiter. A team led by researchers at the Massachusetts Institute of Technology (MIT) has used Webb’s advanced capabilities to identify 138 previously undetected small asteroids, ranging from the size of a bus to that of a stadium. These asteroids, which are smaller than any previously observed in the main asteroid belt, have provided new insights into the evolution of solar system bodies.
By analyzing Webb’s observations of a distant star, the team discovered a population of asteroids that were otherwise too small to be detected by traditional ground-based telescopes. Understanding the distribution and size of these asteroids sheds light on how collisions in the asteroid belt have shaped their current forms and how some might have escaped the belt over time. These processes are crucial to understanding how meteorites, some of which end up on Earth, are formed.
Tom Greene, an astrophysicist at NASA’s Ames Research Center, emphasized the significance of this finding: “We now understand more about how small objects in the asteroid belt are formed and how many there could be. Asteroids of this size likely formed from collisions between larger bodies and are expected to drift toward the Earth-Sun vicinity.”
This research not only adds to our understanding of asteroid evolution but also has implications for planetary defense. Insights from this study will support NASA’s Asteroid Threat Assessment Project (ATAP), which is focused on modeling and mitigating the risks of asteroid impacts with Earth. ATAP, working with NASA’s Planetary Defense Coordination Office, aims to assess the potential threat posed by near-Earth objects (NEOs) and develop strategies for mitigating such risks.
Jessie Dotson, an astrophysicist at Ames and a member of ATAP, highlighted the broader implications of the findings: “Understanding the sizes, numbers, and evolutionary history of smaller main belt asteroids provides crucial background for studying near-Earth asteroids that we monitor for planetary defense.”
The breakthrough was made possible by a novel image-processing technique developed by Artem Burdanov and Julien de Wit at MIT. The team analyzed over 10,000 images of the star TRAPPIST-1, which were originally taken to investigate the potential for life on exoplanets orbiting the star. The asteroids, which were likely passing in front of the star during its observation, were revealed thanks to their infrared brightness—Webb’s primary detection wavelength.
In addition to advancing our understanding of the asteroid belt, NASA will continue to study these objects with upcoming missions. The Near-Earth Object (NEO) Surveyor, set to launch in the near future, will be the first space telescope dedicated to searching for potentially hazardous asteroids and comets that might pose a risk to Earth.
The groundbreaking research paper, “Detections of Decameter Main-Belt Asteroids with JWST,” was published on December 9 in Nature.
As the world’s premier space observatory, the James Webb Space Telescope continues to offer unparalleled views of our solar system and beyond, solving long-standing mysteries about the origins and evolution of celestial bodies. Webb is a collaborative effort between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA).