Astrophysicists have caught a glimpse of an asteroid before it hits Earth for only the sixth time in recorded history.
And on November 19, 2022, nearly four hours before the collision, the Catalina Sky Survey detected an asteroid named 2022 WJ1 on an inner trajectory. And a network of telescopes and scientists was launched into action, to calculate precisely when and where the asteroid will fall on the globe.
2022 WJ1 was too small to do any serious damage, but its discovery shows that the world’s asteroid-monitoring technologies are improving, giving us a better chance of protecting ourselves from falling space rocks – large ones that might actually do some damage, according to Scienceert.
And while space is mostly space, there is a host of lack of space in it as well. And close to Earth, this non-space is mostly asteroids orbiting the Sun in such a way that they come close to Earth’s orbit. We call them near-Earth asteroids, and at the time of writing, 30,656 of them have been cataloged.
Most of these asteroids are actually very small, and scientists are confident that we’ve found almost all of them large enough to pose a major threat, studied them, and determined that none of them will come close enough over the next century to be a threat.
Still, it’s a good idea to stay abreast of what’s going on in the space around us, and hone our abilities to find tricky rocks considering making a grand entrance.
2022 WJ1 was detected at 04:53 UTC on November 19, 2022, by the Mount Lemon Observatory, part of the Catalina Network. It continued observing the object, taking four pictures that allowed the astronomers to confirm the discovery, and reporting it to the IAU’s Minor Planet Center at 05:38 UTC.
And those four images were enough to calculate the asteroid’s trajectory across the sky, with multiple impact monitoring programs finding that the rock had a 20 percent chance of falling somewhere on the North American continent.
Follow-up observations allowed the scientists to refine their measurements, given the time and location. Bang on schedule, at 08:27 UTC, 2022 WJ1 was seen zigzagging across the sky as a bright green fireball, over the Golden Horseshoe region of southern Ontario, Canada.
The discovery was the first meteorite ever predicted to fall over a densely populated area, but the rock did not pose a danger. It is about 1 meter (3.3 feet) wide when it enters Earth’s atmosphere, making it the smallest pre-atmospheric asteroid ever observed to date.
Here it turned into a flaming bolt and shattered, and fell to the ground in smaller pieces that mostly fell into the waters of Lake Ontario. Most of the identifiable pieces of the meteorite must have been small pieces of debris; Scientists hope to recover some of them to study the asteroid further.
The previous five asteroids discovered before the impact were 2008 TC3, which was about 4 meters in diameter; 2014 AA, 3 meters wide; 2018 Los Angeles, three meters wide; 2019 MO at 6 meters; And earlier this year, the 2022 EB5, which was about two meters wide, happened.
And the discovery of 2022 WJ1, and the global coordination it tracked, is a great testament to how sensitive technology has grown, and how amazing human collaboration is to better understand rogue space rocks.
Of course, these observations represent a rare opportunity to study what happens to asteroids when they enter Earth’s atmosphere.
Astronomer and physicist Peter Brown of the University of Western Ontario said: “This fireball is particularly important as the parent meteorite was observed telescopically before it hit the atmosphere. This makes it a rare opportunity to link telescopic data from an asteroid to its behavior in the collapse in the atmosphere to gain insight into its structure.” The interior “..and this remarkable event will provide clues about composition and strength that when combined with telescopic measurements will inform our understanding of how small asteroids break through the atmosphere, which is important knowledge for planetary defence.”
And the 2022 WJ1 wreck should be dark, with a thin, fresh fusion crust, and a gray stony interior. Scientists ask that any suspicious parts be reported to the Royal Ontario Museum.