Last week, the large asteroid called 1998 OR2 was making its closest approach to Earth. The rock was discovered in 1998, which measures about 2.5 miles or 4 kilometers wide. It flew by Earth on April 28 at a range of about 3.9 million miles or 6.3 kilometers, which is about 16 times the distance between Earth and the moon. The intriguing part is not the distance, but it was the asteroid's size.

Consequently, a bright speck in the night caught the eyes of scientists poring through the data gathered by the Pan-STARRS Observatory in Hawaii and found a previously unknown small space rock that is super close to Earth. Its initial sighting sent planetary defense experts around the world in commotion because the first hour of observations of the rock suggested that the rock had a 10% chance of colliding with Earth.

New asteroid safely passes by Earth

Observatories around the world were on the case of the new asteroid that might hit the Earth, tracking the object within an hour after 1998 OR2 safely passes by. As scientists gathered more measurements, their concerns dissipated and concluded that the small asteroid was going to pass by Earth safely.

Now dubbed 2020 HS7, small asteroids like this safely pass by Earth a few times per month, according to Lindley Johnson, NASA's Planetary Defense Officer, in a statement released on April 28. He said that it is no threat to our planet, and if it were to collide with Earth, it would simply be disintegrated by the Earth's atmosphere because of the asteroid's small size.

Indeed, it was an impressively close flyby. The 2020 HS7 asteroid passed by 26,550 miles or 42,735 kilometers away from the Earth's center and just 750 miles or 1,200 kilometers from the nearest satellite in geostationary orbit-one of the more distant rings of satellites surrounding Earth- the European Space Agency (ESA) said. 2020 HS7 flew below the satellite, so it was left unharmed.

Planetary defense system at work

As of present, the recent flyby is one the five closest ever recorded, according to ESA. The flyby is rather more interesting to scientists than the more famous and distant flyby of the bigger asteroid 1998 OR2, which happened in the same week.

Both 2020 HS7 and 1998 OR2 flybys show the way planetary defense systems are designed to work. It started with identifying as many asteroids as possible, beginning the largest one. After that, they track those asteroids long enough to plot their orbits.

The more data the astronomers can gather, the more accurate their plotted orbits become, hence the downgrade from a 10% chance of hitting Earth to a safe miss.

But if more observations show the probability of the asteroid hitting Earth increase, alert systems are enacted to prepare areas that are at risk, and evaluate possible mitigation approaches. Fortunately, these measures were not necessary for 2020 HS7 as it did not hit Earth.