On August 16, the Zwicky Transient Facility (ZTF), a robotic survey camera located at Palomar Observatory near San Diego, spotted an asteroid that had, just hours earlier, traveled only 1,830 miles (2,950 kilometers) above Earth’s surface. Designated 2020 QG, it is the closest known asteroid to fly by Earth without impacting the planet. The previous known record-holder is asteroid 2011 CQ1, discovered by the Catalina Sky Survey in 2011, which passed above Earth about 1,550 miles (2,500 kilometers) higher than 2020 QG.
Asteroid 2020 QG is about 10 to 20 feet (3 to 6 meters) across, or roughly the size of an SUV, so it was not big enough to do any damage even if it had been pointed at Earth; instead, it would have burned up in our planet’s atmosphere.
“The asteroid flew close enough to Earth that Earth’s gravity significantly changed its orbit,” says ZTF co-investigator Tom Prince, the Ira S. Bowen Professor of Physics at Caltech and a senior research scientist at JPL, which Caltech manages for NASA. Asteroids of this size that fly roughly as close to Earth as 2020 QG do occur about once a year or less, but many of them are never detected. (Read more from “Robotic Telescope Finds Closest Known Asteroid to Fly by Earth” HERE)