Smallest asteroid ever spotted hit Earth over Canada in a stunning green fireball

The smallest ever asteroid to hit Earth and the only one to be properly measured is about the size of a regular cat, as per a study. It exploded over Canada in 2022 in a stunning green fireball. The tiny asteroid was discovered only three hours before it made an impact on our planet.

The study was published on Nov 22 in The Planetary Science Journal.

On Nov 19, 2022, asteroid 2022 WJ1 entered the Earth's atmosphere and violently broke apart due to intense friction from the air. This led to a bright flash of green light streaking in the night sky for about 10 seconds. It was accompanied by a loud sonic boom and could be seen many kilometres away.

The explosion was reported in southern Ontario but was watched by people even in the Toronto area and in the states of New York, Ohio, Pennsylvania and Maryland, as per a New York Times report. 

The asteroid was spotted merely three hours before entering Earth by the Catalina Sky Survey in Arizona. In order to learn where it might hit, the team ran tests and was able to correctly predict the location. 

It was also an opportunity to study the space rock and so they quickly enabled the equipment along the asteroid's path.

Also Read: Asteroid hits Earth near California moments after being discovered

This included the 4.3-meter Lowell Discovery Telescope (LDT) in Arizona and a meteor camera network at Western University in Ontario. Both these helped scientists monitor the space rock closely as it raced through the sky.

Using the data of the LDT and the cameras, researchers ran an analysis of the asteroid's brightness. The space rock was found to be around 16 to 24 inches (40 to 60 centimetres) wide, the smallest confirmed size for any asteroid, researchers wrote in a statement.

Asteroids smaller than 2022 WJ1 hit Earth almost every day. However, they have never been measured because the scientists never see them coming. In the case of 2022 WJ1, they were prepared because they spotted it a few hours before impact.

NASA keeps an eye on the potentially hazardous bigger asteroids, but there are a few that are spotted merely hours before impact. At that time,  2022 WJ1 was only the sixth asteroid to be detected right before entering Earth.

Asteroid hits California

This has already happened three times this year. On Oct 22, an asteroid was found moments before impact. It was only around three feet in diameter and burst into a bright fireball about 1,000 km off the California coast. NASA’s Center for Near Earth Object Studies (CNEOS) spotted it and reported that a fireball lit the skies at 3:54 am PT.