'30 times Hiroshima': James Webb Space Telescope finds 138 asteroids, 6 on paths toward Earth

Produced by: Mohsin Shaikh

Credit: Ella Maru/ Julien de Wit/ MIT (CC BY-NC-ND 4.0)

Astounding Discovery

Archival images from the James Webb Space Telescope (JWST) revealed 138 new small asteroids, including six on Earth-bound trajectories, reshaping planetary defense efforts.

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Small Threats

The newfound "decameter" asteroids, ranging from bus to stadium-sized, pose significant risks despite their size, colliding with Earth 10,000 times more often than larger counterparts.

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Hidden Dangers

Using 93 hours of JWST images, astronomers identified the smallest asteroids ever seen in the main belt, proving how modern technology can uncover previously undetectable threats.

New Method

Julien de Wit of MIT credits a computationally intensive approach, using GPUs to enable "blind searches," for this unprecedented asteroid tracking capability.

Credit: MIT kavli institute

Thermal Detection

JWST's infrared technology revealed the asteroids’ heat emissions, far superior to traditional methods relying on faint reflected sunlight, making the discovery possible.

Historical Context

The Chelyabinsk event, caused by a small asteroid, released 30 times Hiroshima’s energy, underscoring the destructive potential of decameter asteroids.

Future Exploration

Upcoming JWST missions will study 15–20 distant stars for 500 hours, potentially uncovering thousands more asteroids and broadening the understanding of solar system dynamics.

Ground Breakthrough

Chile’s Vera C. Rubin Observatory, launching next year, will map the southern sky nightly, doubling the asteroid catalog within six months with its unparalleled digital camera.

Planetary Defense

Artem Burdanov emphasized that early detection of small asteroids enables precise orbital tracking, a critical step for mitigating risks and improving planetary defense.