Update Feb 26, 2021: Researchers have discovered what caused the giant fireball that lit up the sky earlier this week.
On Monday morning just before 6:30, hundreds of Albertans from Calgary to Fort McMurray reported seeing a bright flash in the sky.
The phenomenon was even witnessed by some people in Saskatchewan.
Now, scientists at the University of Alberta believe the bright, cosmic light was a small piece of a comet that burned up in the atmosphere.
“Using two observation sites, we were able to calculate both its trajectory and velocity, which tell us about the origin of the meteor and reveal that it was a piece of a comet,” said Patrick Hill, with the Department of Earth and Atmospheric Sciences.
“This chunk was largely made of dust and ice, burning up immediately without leaving anything to find on the ground—but instead giving us a spectacular flash.”
Researchers said the comet streaked through the sky to a final point on its trajectory 120 kilometres north of Edmonton.
The small piece of space rock, likely only tens of centimetres across in size, was travelling at more than 220,000 km/hr when it entered the atmosphere.
“This incredible speed and the orbit of the fireball tell us that the object came at us from way out at the edge of the solar system—telling us it was a comet, rather than a relatively slower rock coming from the asteroid belt,” said Chris Herd, curator of the UAlberta Meteorite Collection.
“Comets are made up of dust and ice and are weaker than rocky objects, and hitting our atmosphere would have been like hitting a brick wall for something travelling at this speed.”
The fireball lit up social media on Monday as Albertans shared their photos and video of the event.
The team from the University of Alberta used Western Canada’s most advanced fireball network to calculate the trajectory of the fireball, using dark-sky images captured at the Hesje Observatory at the Augustana Miquelon Lake Research Station and at Lakeland College’s observation station in Vermilion.
While nothing has been found on the ground, it is a relief to some that the mystery of the fireball has been solved.
“This is an incredible mystery to have solved,” said Herd. “We’re thrilled that we caught it on two of our cameras, which could give everyone who saw this amazing fireball a solution.”