For only the sixth time in recorded history, astronomers have caught a glimpse of an asteroid before it hits Earth.
On November 19, 2022, nearly four hours before the collision, the Catalina Sky Survey detected an asteroid named 2022 WJ1 on an inner trajectory.
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 – big ones that might actually do some damage.
And although space is mostly space, there is a host of lack of space in it as well.
There are mostly asteroids orbiting the sun in such a way that they are close to Earth’s orbit. We call them near-Earth asteroids.
However, it’s a good idea to stay abreast of what’s going on in the space around us, and hone our abilities to find trick-or-treaters thinking of making a grand entrance.
2022 WJ1 was detected at 04:53 UTC on November 19, 2022, by the Mount Lemmon Observatory, part of the Catalina Network. The researchers continued to observe the object, taking four images that allowed the astronomers to confirm the discovery, and report it to the IAU’s Minor Planet Center at 05:38 UTC.
These 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 time and location. 2022 WJ1 was seen shooting across the sky as a bright green fireball, over the Golden Horseshoe in southern Ontario, Canada.
This discovery was the first expected meteorite ever to fall over a densely populated area, but the rock did not pose a danger. It is about one meter (3.3 feet) wide when it enters the Earth’s atmosphere, making it the smallest asteroid that has been detected so far before entering the atmosphere so far.
Here it turned into a blazing bolt and shattered, falling to the ground in smaller pieces that mostly fell into the waters of Lake Ontario. Most of the identifiable meteorite pieces must be small pieces of debris; Scientists hope to recover some of it to study the asteroid further.
The discovery of 2022 WJ1, and the global coordination it tracks, is a great testament to how sensitive the 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.