Researchers at Western University are hoping the public will be able to help them recover meteorites from a fireball that streaked across the sky in southwestern Ontario.
The bright meteor was spotted just before 3:30 a.m. on Saturday.
Members of the Western Meteor Physics Group and the Institute for Earth and Space Exploration flocked outdoors to watch the fireball after being given advance notice of its existence. The Catalina Sky Survey in Arizona detected the small asteroid, now designated 2022 WJ1, just three hours before it entered Earth's atmosphere just south of Woodstock.
It proceeded eastward until its end at 20 km altitude North of the town of Vineland, according to Western University.
“It passed right overhead at the predicted time and was distinctly green in colour,” said David Clark, a geophysics doctoral student, who drove to the predicted fall area to see it light up the night sky. “Several minutes later a noticeable sonic boom could be heard.”
Using video data analysis, researchers have determined that fragments of the meteor likely landed to the north of St. Catharines.
“This fireball is particularly significant as the parent meteoroid was observed telescopically before it hit the atmosphere. This makes it a rare opportunity to link telescopic data of an asteroid with its breakup behaviour in the atmosphere to glean insight into its internal structure,” said Peter Brown, Western's Canada Research Chair in Planetary Small Bodies.
Until now there have only been six other asteroids in history to have had advanced warning of impact. This is the first time the predicted event happened over a heavily populated area with fireball measurement equipment in place. Six cameras in Western's All-Sky Camera Network and Western’s Canadian Meteor Orbit Radar detected the fireball.
“This remarkable event will provide clues about the makeup and strength which when combined with telescopic measurements will inform our understanding of how small asteroids break up in the atmosphere, important knowledge for planetary defence,” said Brown.
The pressure is now on to collect meteorites associated with 2022 WJ1.
“We know from camera records and weather radar which tracked falling debris from the fireball that meteorites almost certainly made it to the ground near or east of Grimsby. What we need now to complete this story is to recover some of these rocks and find out what kind of material made up asteroid 2022 WJ1,” said Brown. “This is very much like a sample return space mission, but in this case the sample fell on us.”
Meteorites are dark coloured and often have a scalloped exterior. They are also denser than a normal rock and will often be attracted to magnets due to their metal content. While meteorites aren’t dangerous, they are fragile. Researchers suggest anyone who finds one put it in a clean plastic bag or wrap it in aluminum foil for protection and handle it as little as possible.
Anyone thinking of joining the search for the space-rocks is advised to get permission from landowners, as meteorites belong to the owner of the land upon which they are found in Canada.
Residents who heard anything unusual or who have found a potential meteorite from this event are asked to contact the Royal Ontario Museum at naturalhistory@rom.on.ca.