Another asteroid was sighted just a few hours before impact with the Earth: this is the sixth sighting and the second occurred this year.
The asteroid 2022 WJ1 was discovered at 05.53 Italian time on November 19 thanks to the Mount Lemmon Observatory, in the United States, which is part of the Catalina Sky Survey of the University of Arizona, one of the largest projects dedicated to observation of objects close to our planet.
The small asteroid, about a meter in diameter, fell over the border between the United States and Canada, and the small pieces into which it disintegrated ended up mostly in Canadian Lake Ontario.
After the first sighting, the Catalina Sky Survey telescope managed to take four photographs of the object, alerting the Minor Planet Center, commissioned by the International Astronomical Union (IAI) to collect data on asteroids and comets and to calculate their orbit.
The four photos were enough to map the asteroid's path and, thanks to the publication of those data, the monitoring software of the European Space Agency (ESA) calculated, in a few minutes, the place and time of the probable impact.
Exactly at the scheduled time, 09.27 am Italian time, the asteroid hit the atmosphere becoming a brilliant ball of fire.
The detection of asteroid 2022 WJ1 shows that monitoring techniques are getting better and better, increasing the chances of spotting even objects that could cause damage in time.
It is estimated that in the Solar System there are 40-50 million small asteroids, over a million intermediate objects and about a thousand larger ones: of all these, we know only a little more than a million, and about 30,600 travel on orbits that they bring them close to the terrestrial one.
The good news is that nearly all of the giant asteroids have been found and none of them will be of concern for the next hundred years, while smaller asteroids hit Earth on average every two weeks.