Astronomers spot smallest asteroid just hours before it explodes in Canada

In the early hours of November 19, 2022, a small asteroid designated 2022 WJ1 entered Earth's atmosphere and exploded above Canada, specifically illuminating the skies over Niagara Falls. Measuring between 16 to 24 inches in width, this space rock is the smallest asteroid to be properly measured before impact. Discovered by astronomers from the Catalina Sky Survey in Arizona only three hours prior to its atmospheric entry, 2022 WJ1 provided a rare opportunity for researchers to monitor and analyze its approach. This event triggered a bright green fireball visible for about ten seconds, accompanied by a loud sonic boom, showcasing the potential dangers posed by near-Earth objects of even small sizes. The asteroid's trajectory was successfully predicted, allowing scientists to deploy monitoring equipment in its path, including the Lowell Discovery Telescope and specialized cameras from Western University in Ontario. This collaboration marked the first time that data from telescopic observations were combined with fireball camera data for such an event, enabling researchers to make precise predictions about the asteroid's size and composition. Although smaller asteroids impact Earth frequently, they often go unnoticed, leading to the classification of 2022 WJ1 as exceptionally notable. Only six asteroids have been observed before entering the planet's atmosphere since monitoring began, and this incident highlights advancements in tracking technologies and observational techniques that allow astronomers to detect these incoming threats. The research findings were published in The Planetary Science Journal on November 22, 2022, revealing that detecting and predicting asteroid impacts is becoming increasingly feasible, thus enhancing scientists' preparedness for potential future events. In the aftermath of the explosion, the fragments of 2022 WJ1 were unlikely to be recovered, as most were expected to have fallen into Lake Ontario. However, the unforeseen nature of this event serves as a reminder of the ongoing need for vigilance in monitoring asteroids and understanding their mechanics. This observation signifies a growing capability among scientists to predict and respond to asteroid impacts, which could ultimately be crucial for planetary defense strategies in the coming years.