On Sunday, a major astronomical event happened as an asteroid about as big as the size of a car flew within about 1,830 miles (2,950 kilometers) of the Earth.
The distance was the closest ever recorded, according to asteroid trackers and the Sormano Astronomical Observatory in Italy. The arrival of the asteroid was not predicted by astronomers and was a surprise as it passed by the Earth. Director of NASA's Center for Near Earth Object Studies said that the asteroid approached undetected from the direction of the sun and no one saw it coming.
The asteroid was, in fact, first detected by California's Palomar Observatory 6 hours after it passed by the planet.
Many of the asteroids do not even cross the telescope's line of sight, which means that NASA has been able to detect only a fraction of Near Earth Objects (NEOs) like this one. This also poses danger as in case a potentially dangerous rock from outer space slipped through the gaps in the NEO-Surveillance systems, it could kill tens of thousands of people.
The latest asteroid is familiar to astronomers by the name 2020 QG and was initially called ZTF0DxQ.
The asteroid travelled with a speed of about 7.7 miles per second and passed less than 1/4th of the Earth's diameter. It surprisingly didn't hit the Earth but even if it had, it wouldn't have caused any damage because of its size. It was observed that the asteroid flew over the Southern Hemisphere just after 4 a.m. Universal Time. The International Astronomical Union's Minor Planet Center calculated a different trajectory, though, and suggested that the rock flew over the Pacific ocean.
Newly-discovered asteroid ZTF0DxQ passed less than 1/4 Earth diameter yesterday, making it the closest-known flyby that didn't hit our planet.@renerpho— Tony Dunn (@tony873004) August 17, 2020
Higher-res GIF: https://t.co/4Wxn0YNpVb pic.twitter.com/SMtVRbjYOA
The size of the asteroid has been measured to be 6-18 feet wide. It is suggested that only small pieces of the rock might have hit the Earth. The asteroid would have possibly exploded in the atmosphere, creating a fireball and causing an immense airburst which would have happened about 2-3 miles above the ground. Therefore, it would have produced a sound only as loud as the road traffic to people on the Earth.
NASA said that it can not do much about detecting inbound asteroids that come from the sunward direction as optical telescopes like ZTF that detect asteroids can only search for them in the night sky.
NASA does, however, aim to discover asteroids on one of their prior passages by the Earth and then make "predictions years and decades in advance'' to learn about their possible impact. Moreover, NASA also plans to address the gaps in its asteroid detection system and is currently in the early stages of developing a space telescope that could detect rocks and comets coming from the sun's direction. With continued funding for the telescope, it could come out as soon as 2025.