A rare fireball streaked across the Alberta skies on February 22, catching the eye of the Athabasca University GeoSpace Observatory’s all-sky cameras.
Fireballs happen when large meteoroids — space rocks — slam into the Earth’s atmosphere at high speed, leaving a bright trail behind. Usually such fireballs only last a few seconds. As the rock burns up in the atmosphere, the resulting “shooting star” is more officially known as a meteor. And AU was lucky to view the event. (Full disclosure: the article’s author is a history student at Athabasca University, but not involved at all in this meteor work.)
“Since our cameras are very sensitive aurora cameras — in fact some faint aurora is just visible in these images — we did not capture the meteor itself [because] our frames were completely blanked out by the bright light,” said Martin Connors, a physics professor at AU who developed the AUGO observatory to observe auroras and other sky events, in an e-mail interview.
“However, we could follow the trail, which starts out as a straight line as most other images would show. The energy deposited causes chemical reactions that give off light,” he continued. “The black-and-white image shows a lot of detail in the trail about 30 seconds after it happened. In the colour image, [the trail] has been further distorted by upper atmospheric winds about 50 kilometres up.”
Connors cautioned that the images are enhanced, so the dawn light you see is a little brighter than what the eye would have perceived. The dust in the sky may be giving off some of the reflected light, but he said most of the brightness comes from the “chemiluminescence” resulting from the chemical reactions. “I think the green colour in the enhanced colour shot is real,” he said.
A long regional history
Meteor research in the Athabasca region hit a previous high point with a Meteor Observation and Recovery Project (MORP) that began in the 1950s, Connors said. While most meteors burn up fully in the atmosphere, occasionally there is a fireball big enough that allows fragments to hit the ground — fragments that are known as meteorites. (Bigger events, such as the notorious Chelyabinsk bolide that exploded over a northern Russia town in 2013 and caused damage along with raining a few rocks, are relatively rare.)
Athabasca’s MORP stations included Meanook (about 15 kilometers south of Athabasca) and Newbrook (roughly 40 kilometres east of Meanook) and often took photos in pair, using huge Super-Schmidt cameras. The images helped researchers of the day “find several well-known meteorites,” Connors said. One example was the 1952 Abee meteorite, recovered successfully after a bright fireball filled the sky. Modern-day results concerning the meteorite’s orbit were published in the Journal of the Royal Astronomical Society of Canada in February 1992.
While Athabasca University is hitting the news for its recent meteor observations, its Canada Foundation for Innovation-funded observatory specializes in auroras. The university also has a smaller, robotic astronomical telescope that can do wide-sky surveys including meteor work, Connors said.
“We also study auroras using magnetic techniques, and I think the only vestige of the former glory of the Meanook site is ongoing magnetic observations, making a nice combination with our work,” he added.
Other networks and projects
There are several other meteor networks in Canada. Among them, Western University does meteor studies using a radar observatory roughly 100 kilometers from London, Ontario, that records 2,500 meteoroid orbits per day. The radar can also record “ablating” meteoroids and has been doing so in at least some fashion since 1999, according to a Western website on the project. The main orbital radar system was replaced with a modernized one in 2009, allowing for twice the transmission power; as of that time, the original system was maintained as a backup.
The British Columbia Meteor Network is a set of video detectors and radio detectors run by a few professionals and a larger, majority group of amateurs. The original network, opened in 1998, included four all-sky cameras deployed across British Columbia, its website states. The network now includes several mainland sites to enhance coverage capabilities.
Amateurs around the world, including in Canada, can also submit their meteor observations to the American Meteor Society through their fireball reporting form. The advantage of submitting to AMS is it acts as a volunteer alert system for professional astronomers trying to track down the source of meteorites; AMS is also cited frequently in stories worldwide in conjunction with meteoroids, meteors and meteorites.
NASA and its Planetary Defense Coordination Office also have a mandate from United States Congress to keep scanning the skies for larger and even more threatening asteroids, such as Apophis, that will make a safe pass by the Earth on Friday, March 5. NASA, PDCO and the accompanying network of partner telescopes have not found an imminent threat to Earth yet. But being good scientists, they keep looking out to make sure that humanity will not meet the fate of the dinosaurs.
Scientists around the world also regularly study asteroids to learn more about these small worlds’ history, a part of which can be useful for planetary defence. In 2020, two asteroid missions made news; NASA’s OSIRIS-REx (which includes Canadian participation) scooped up a sample from asteroid Bennu to return to Earth in 2023, while Japan’s Hayabusa2 sent a sample return capsule into the Australian desert with materials collected from asteroid Ryugu in December 2020.
NASA and the European Space Agency are working on a joint asteroid defence test mission that will, in essence, see a European probe slam into an asteroid moon and then both the Europeans and NASA will track if the orbit is altered. NASA’s component, the Double Asteroid Redirection Test (DART), has been delayed from a July to August 2021 launch window to a later November 2021 to February 2022 launch window. DART is expected to hit the asteroid and a follow-up probe from Europe, called Hera, will launch in 2024 to look at the aftermath.
Sky News This Week is a biweekly column by Canadian science and space journalist Elizabeth Howell focuses on a trending news topic in Canadian astronomy and space.