On Monday, Sept. 4, 2017, a fireball was seen in the Canadian province of British Columbia. While many of the 300 reports received by the American Meteor Society, or AMS, were from British Columbia, the fireball was also seen in the provinces of Alberta and Saskatchewan. In the United States, it was seen in Idaho, Montana and Washington,.
A light brightened the night sky at 10:14 p.m. PST. The fireball was described as a blazing object that made the sky turn green before changing into a dark orange. Afterward, a loud bang came shaking homes and tall buildings.
A fireball is a very bright meteor—brighter than the planet Venus—that frequently blows up with a bright flash at its finish. Meteors are chunks of space dust or debris that burn in the atmosphere. They only transform into meteorites if they strike the ground. Similarly, a meteoroid is space debris. Meteoroids have several distinct shapes.
A small amount of them are composed of solid irons, while others, like comets, are assortments of ice and dust. If a meteoroid continues its route through the Earth’s atmosphere, then that usually indicates that it is made of solid iron. An unsecured meteoroid will most likely split up in the air.
The AMS assumed that the fireball entered the atmosphere near Boswell, British Columbia. It ended near Meadow Creek, British Columbia, approximately 100 kilometers away. The Southeast District Royal Canadian Mounted Police said numerous calls in the towns of Castlegar, Creston, Nelson and Salmo said that there was a “glowing object streaking across the sky.”
Astronomers say that several thousand meteors of fireball size happen into the Earth’s atmosphere daily. However, because Earth mainly consists of oceans, deserts or unpopulated regions near the poles, most fireballs go unnoticed. Meteoroids enter the earth’s atmosphere at dangerously fast speeds, varying from 11 km/s to 72 km/s but then they slow down. Their mass is drained and the meteoroid is diminished because of its clash with air molecules.
As it drops, the light from the fireball dims making it almost invisible when hitting the ground.
There are two categories of sounds triggered by very bright fireballs, sonic booms and electrophonic sounds—both are uncommon. If the bright fireball is big enough and enters the Earth’s atmosphere under an altitude of 50 kilometers, there is a possibility a sonic boom can be heard on the ground. Canadians said that on Sept. 4 a loud boom followed the fireball.
According to the AMS’s website, “Because sound travels quite slowly, at only 20 kilometers per minute, it will generally be 1.5 to four minutes after the visual explosion before any sonic boom can be heard.”
This was not the first time meteors passed over Canada. In March, a “mysterious fireball” was seen in the night sky over the Metro Vancouver Regional District. The meteor emitted a green flash that was seen in the state of Washington.
On Nov. 20, 2008, a fireball was seen in Alberta, Saskatchewan and Manitoba. The fireball triggered explosions and shadows were created. Several people heard “whirring” sounds, which were assumed to be the result of debris plummeting to the ground.
On Jan. 18, 2000, a fireball was seen over Yukon and northern British Columbia at 8:40 p.m. PST. Loud booms were heard throughout the rural lands.
Corporall Dan Moskaluk said it was challenging to pinpoint where the fireball landed because the skies are still filled from smoke, a result of British Columbia’s worst wildfire season in history.
British Columbia is under a state of emergency until Sept. 15 as the province has experienced over 140 wildfires and 12,000 people remain on evacuation alert. The Sept. 4 fireball has raised potential fears.
“I know that some people were concerned it might be an additional wildfire risk but these objects are not hot when they hit the ground,” said Jaymie Matthews, a professor of astronomy and astrophysics at the University of British Columbia.
Matthews further said that the fireball was around the dimension of a piece of furniture, like a couch.
While there is a possibility that there will be wreckage from the fireball, the chunks would be too small to leave a crater.