On August 16, 2020 undetected asteroid 2020 QG swept past Earth at a distance of 2,900 Km. Described as “truck size” ( 20 feet, 3-6 meters across ), traveling at 12.4 Km per second, 2020 QG approached from a sunward direction. Reason why astronomers didn’t see it until six hours later. Despite post event assurance there was never any danger, it’s sobering to ponder fragility of our existence. Asteroid 2020 QG now holds the record for closest “known” asteroid to pass without an Earth strike.
View larger. | This illustration shows asteroid 2020 QG’s trajectory bending during its close approach to Earth. The asteroid is the closest known nonimpacting asteroid ever detected. Image via NASA/ JPL-Caltech.
View larger. | The blue ball in the lower left of this image represents Earth. The curved green arrow represents asteroid 2020 QG, whose orbit was changed by its near-Earth encounter on Sunday. The tick marks on the green line represent 30-minute intervals. You can see that this asteroid was really zooming past! Image via Minor Planet Center.
Science admits “gaps” in detection of sunward approaching asteroids. Current telescopes can only detect asteroids at night. When identified, orbit is calculated to determine potential for a future collision. Rather clunky if you ask me. NASA is in early stage development of a telescope to detect asteroids and comets coming from the Sun’s direction. If all goes well and funding remains in place, the Near-Earth Object Surveillance Mission could be operational by 2025.
For now all we can do is hope incoming sunward objects aren’t pesky enough to unleash calamity.