This was explained by the engineer. Majed Abu Zahra
On Monday, May 31, 2021, two asteroids discovered at the Kiso Observatory in Tokyo, Japan were recorded, one day before they approached simultaneously within close proximity to the Earth without the risk of collision.
The asteroid called 2021 KN2 passed near Earth at a distance of 0.38 lunar distance (145,109 km), and it belongs to a group of asteroids called Apollo, and its diameter is between 5 and 11 meters, and it is the number 58 known asteroid that crosses within one lunar distance (384,401 km) since the beginning of the year 2021 and the seventh until Now this month.
As for the second asteroid, it bears the name 2021 KO2 through the proximity of the Earth at a distance of 0.96 lunar distance (371,002 km). It has passed within one lunar distance (384,401 km) since the beginning of the eighth year so far this month.
The two asteroids are too small by standard asteroid standards and are not visible to the naked eye, and if we assume that they were on a collision course, they would likely become fireballs as they crash into the upper atmosphere of the Earth, an event that occurs several times a year for space rocks of this size.
By some estimates, there are hundreds of millions of small asteroids the size of these but they are extremely difficult to detect until they come very close to Earth, and in total the vast majority of them pass safely over much greater distances – usually much farther than the Moon.
In general it is a huge achievement to find these small asteroids nearby in the first place, because they pass very quickly, and there is usually a short window of a few days before or after the approach when this small asteroid is close enough to Earth to be bright enough but not too close So that it moves very quickly in the sky.