Monday, February 22nd 2021, 9:46 pm - Did you see it? Over 150 reports have come in from across western Canada.
The pre-dawn sky over central Alberta briefly turned green Monday morning, lit up by an impressive fireball meteor blazing through the air.
According to NASA, it's estimated that Earth sweeps up several metric tons worth of space dust every day, as the planet travels along its orbit around the Sun. Once in a while, however, something a little bigger gets in our way, and it makes itself known to us in spectacular fashion.
This is what occurred at around 6:22 a.m. MST, on the morning of February 22, 2021, a little over 50 kilometres north of Edmonton, Alberta.
This dashcam view of the fireball (and closeup, inset) shows off the meteor's brightness and green tinge. Credit: Joey Joey/UGC
A small meteoroid — exactly how big is not known — plunged into the upper atmosphere, and blazed a bright green trail through the air before it fizzled out. This meteor flash was so intense, and occurred so high above the ground, that witnesses from hundreds of kilometres around spotted it.
This 'heat map' shows the approximate location of the meteor trail (green arrow), with the splotches of colour indicating the concentration of the reports received by the American Meteor Society as of the afternoon of February 22. Credit: AMS
Due to the relatively clear skies over the west Monday morning, the flash was reported from as far south as Helena, Montana (roughly 500 km south of Calgary). As of the afternoon of February 22, the American Meteor Society had a total of 158 reports of this meteor.
Anyone who spotted it is encouraged to submit their own report, to get the most complete record of the event possible.
SEEN FROM SPACE
This fireball was not only bright enough to be seen by witnesses from hundreds of kms around, it was also seen by satellites in space.
Both Geostationary Lightning Mapper instruments, on board the GOES-16 and GOES-17 geosynchronous weather satellites, spotted the meteor flash.
WHAT'S GOING ON HERE?
Out in space, between the planets, there are likely millions of tiny bits of rock and ice and dust, floating around the Sun. These are all leftover pieces from the formation of the solar system, over 4.5 billion years ago. As they orbit the Sun, these meteoroids are travelling at speeds of tens to hundreds of thousands of kilometres per hour. So, if their path happens to intercept Earth, they plunge into the atmosphere at high speed.
As the meteoroid encounters air molecules in its path, it compresses those molecules together. This slows the meteoroid down, and if it compresses the air hard enough, that air will glow. This is the 'meteor' flash that we see.
If these meteoroids are extremely small, such as microscopic dust grains, we may not notice at all. If something bigger — the size of a grain of sand up to a pebble or even larger — passes over places we inhabit, though, they are much more noticeable. The larger and faster moving the meteoroid is, the brighter the resulting meteor will be. Brighter ones are referred to as fireballs, while the brightest (which usually involve the meteoroid exploding during flight) are often called bolides.
The colours of these meteors depend on a number of factors. This includes the concentration of gases that are compressed ahead of the meteoroid, and even what kinds of minerals and metals are found in the meteoroid, itself.
If a meteoroid is large enough, and moving slowly enough as it makes its plunge through the atmosphere, pieces of it can reach the ground intact. If we find these, we call them meteorites.