Smallest asteroid ever measured explodes over Canada near Niagara Falls

A new study reveals that asteroid 2022 WJ1, which exploded over Canada in November 2022, is the smallest asteroid ever measured, measuring about 20 inches wide. It was discovered just hours before its explosion. The asteroid created a bright green fireball visible for miles and was monitored by telescopes and cameras. This event marked only the sixth time an asteroid was spotted before entering Earth's atmosphere. Researchers are improving their ability to detect such small asteroids. They have now identified ten early impactors, including three in 2024. No fragments of 2022 WJ1 were recovered, as most likely fell into Lake Ontario.