Asteroid 1998 SD9 will fly by Earth at a distance of 2.5 million kilometers. According to NASA, its width varies between 44-100 meters.
This asteroid is considered potentially hazardous as all space objects approaching the Earth at a distance of less than 7.5 million kilometers.
Another asteroid - 2021 SG - was closer to Earth in mid-September. It flew a short distance from our planet to the Moon (384,000 kilometers). Its size was about 70 meters, and NASA found out about its approach to Earth a day later.
It shows that if there were a collision with our planet, no one would have known about the imminent catastrophe.
The recognition problem was created because it was coming from the direction of the sun. It is very difficult to see such asteroids because the sun's rays block the view.
