Astro Bob: Asteroid discovered just hours before crashing to Earth
A meter-wide asteroid came down over southern Ontario not far from Niagara Falls this weekend. Astronomers saw it coming.
For just the sixth time in history, astronomers spotted an asteroid in space before it struck the planet. David Rankin , working with the NASA-funded Catalina Sky Survey , whose mission is to find and track potentially hazardous near-Earth asteroids and comets, nabbed the space rock approaching Earth at 11:53 p.m. Eastern Time on Friday, Nov. 18.
"I could tell from the discovery images that the object was likely in near-Earth space and closing in," wrote Rankin on Facebook . "We posted online in various places asking for follow up help and tracked it ourselves."
Based on preliminary calculations of its orbit, the object, now called 2022 WJ1, would slam into the atmosphere and produce a spectacular fireball over the Great Lakes region just a few hours after its discovery.
Word went out on Twitter and Facebook for observers to keep watch. Sure enough, 3 1/2 hours later, at about 3:28 a.m. EST, what had been a fast-moving, star-like point of light in the sky, came crashing down, producing a radiant green flash and a powerful sonic boom over Hamilton, Ontario, and the Niagara Falls region. As of Sunday, Nov. 20, the American Meteor Society has received 54 reports of the object from as far away as Indiana and Maryland.
Doorbell and security cameras recorded the brilliant object as it shattered into pieces during its long flight. Doppler weather radar in the region picked up signs of meteorites falling along the south shore of Lake Ontario. While most of the fragments may be underwater, the data indicate there's a good chance some of the material landed in the cities of Grimsby and McNab, located east of Hamilton.
Space "rocks" like 2022 WJ1, estimated at 1 meter (3 feet) across before impact, aren't considered a threat because they break apart into smaller, relatively harmless pieces after striking the atmosphere at tens of thousands of miles an hour. Between 40 and 100 tons of natural space debris enter Earth's atmosphere every day, most of it as dust but occasionally as boulder-sized rocks. There's a lot of empty space out there, but the solar system has yet to completely clean up its act. Debris from asteroid collisions will always be a concern.
The first asteroid found and tracked before impact, 2008 TC3, crumbled over Sudan on Oct. 7, 2008 and showered the Nubian Desert with a unique suite of meteorites. That one measured 13 feet (4.1 meters) wide and weighed about 90 tons. The most recent was 2022 EB5 , a 6-foot-wide (2-meter) rock that landed in the Arctic Ocean north of Iceland on March 11 this year.
Diligent observers and rapid reporting, followed by confirmation and sharing on social media made it possible for observers to be in position to observe and photograph the asteroid's demise just hours after discovery. Even if that meant a 3 a.m. wake-up call!
If you find the news of all this unsettling, look on the bright side. Nearly all the bigger asteroids, the ones that could do the most damage, like destroy civilization, have been discovered. That leaves mostly smaller and medium-sized objects. Some of those are obviously still cause for concern. But we can feel good knowing that Rankin and his ilk intend to find every last one of them.