Earth Avoids Asteroid by Narrowest of Margins
If you’ve ever gone to the visitor’s center for ‘meteor crater’ near Winslow Arizona, you may remember the guide explaining that the asteroid responsible for that enormous hole in the ground was about 130 feet wide.
It turns out that earlier this month, the Earth came very close to getting another similar size scar as an asteroid, estimated to be ten to twenty feet in diameter, passed closer to the planet than any other recorded so far – without impacting.
What’s perhaps even scarier – no one saw it coming.
The near-miss on August 16, by what has been named asteroid 2020 QG, was not known until after it had already passed.
As reported by the National Science Foundation, astronomers at the Zwicky Transient Facility (ZTF), a robotic survey camera located at the Palomar Observatory near San Diego, detected the asteroid just a few hours after it narrowly missed the Earth.
“The asteroid flew close enough to Earth that Earth’s gravity significantly changed its orbit,” says Zwicky Transit Facility co-investigator Tom Prince, a physicist at Caltech. 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.
Credit: NASA/JPL
Doing the math and retracing 2020 QG’s path, they have calculated that it missed hitting the earth by only a mere 1,830 miles or 2,950 kilometers. That’s less than width of the continental United States.
The last asteroid to pass so dangerously close to our home planet was 9 years ago when asteroid 2011 CQ1 missed the Earth by about 3400 miles (5500 km).
Because this asteroid was a good deal smaller than the one that created Meteor Crater, it’s likely that it would have mostly burned up entering the Earth’s atmosphere if it had been a direct hit. But it still illustrates how precarious our existence truly is.
The asteroid that wiped out the dinosaurs (who inhabited the earth for hundreds of millions of years) was about 6 miles in diameter.
If this fly-by 2 weeks ago was 1800 miles closer, and if asteroid 2020 QG was a bit bigger, humans (who have only inhabited the earth for much less than one hundred thousand years – not millions) could easily have gone the way of the dinosaur.
In recent years, additional funding has been allocated for projects to help provide early warning of objects like this which could provide a threat to the Earth. In addition to its hunt for Supernova and other astronomical objects, the ZTF team provides part of that early warning system.
The ZTF combines a very large field lens with machine learning AI systems to quickly analyze images and point out threats like 2020 QG. A close object moving quickly in the sky compared to the background stars, like an asteroid, shows as a streak instead of a dot and is easily identified by the software.
While the software is able to capture and sort through over a hundred-thousand images, and narrow the potential threats to around a thousand – that still means that members of the team need to hand sort and follow up on about a thousand of these images each day.
About the Author
