The asteroid reportedly flew over the Southern Hemisphere just after midnight EDT on Sunday, marking the closest fly-by of Earth on record, according to asteroid trackers and a catalog compiled by Sormano Astronomical Observatory in Italy.
According to NASA’s database of near-Earth objects, the asteroid flew by at nearly 4,778 miles (7,770 kilometers) from the center of our planet. That means it could have been less than 1,000 miles (2,950 kilometers) above our heads at its closest point.
“The asteroid approached undetected from the direction of the sun,” Paul Chodas, the director of NASA’s Center for Near Earth Object Studies, told Business Insider. “We didn’t see it coming.”
Instead, the Mount Palomar Observatory in California saw the asteroid first almost six hours after it flew by the planet. Telescope observations estimate the asteroid had a diameter of about three to six meters, making it somewhere between the size of a car and a pickup truck- reports CTV News Canada.
Chodas confirmed the record-breaking nature of the event: “Yesterday’s close approach is closest on record, if you discount a few known asteroids that have actually impacted our planet,” he said.
The asteroid went by the identifier ZTF0DxQ – but has now been formally entered into NASA’s database as 2020 QG.
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
Simulation: pic.twitter.com/SMtVRbjYOA— Tony Dunn (@tony873004) August 17, 2020
The planet’s telescopes can’t catch every single NEO (near-Earth-object) that passes us, and NASA knows that many don’t cross any telescope’s line of sight. This means that several potentially dangerous NEO’s have snuck past Earth in recent years.
Thankfully, Asteroid 2020QG was not too dangerous. Based on it’s size, it most likely would not have posed any danger to humans had it hit Earth, as it would have exploded upon entering the atmosphere.
A comparably sized asteroid known as ZLAF9B2 (2018 LA) was spotted only eight hours before it hit Earth in June 2018. Only small fragments of the space rock made it to the ground in Africa, causing no reported damage or injuries.
The U.S. Congress has required NASA to scan the skies for NEO’s since 2005. However, the agency is mandated to detect only 90 percent of “city killer” space rocks larger than about 460 feet (140 meters) in diameter.
But detecting asteroids that come from the direction of the sun has always been difficult. “There’s not much we can do about detecting inbound asteroids coming from the sunward direction, as asteroids are detected using optical telescopes only (like ZTF), and we can only search for them in the night sky,” Chodas said.
NASA is in the early stages of developing a space twlwscope capable of detecting asteroids and comets coming from the sun’s direction. NASA’s 2020 budget allotted nearly $36 million for that telescope, called the Near-Earth Object Surveillance Mission. If funding continues, it could launch as early as 2025.