An unusually bright meteor blazed across the St. Louis sky this week before disappearing from view — but not before catching the eye of people from Arkansas to Michigan.
The flash followed by a glowing tail occurred around 9:15 p.m. Wednesday, moving east to west — and was bright enough to count as a “fireball,” according to the American Meteor Society.
Meteor experts compiling eyewitness reports were attempting to learn more about its trajectory Thursday and whether any of its remnants might have reached the ground somewhere.
More than a dozen corresponding reports had been filed in the AMS’ crowd-sourced “Fireball Sightings Log” online by Thursday afternoon — with observers stretching across Missouri and into Illinois, Arkansas, Indiana, and Michigan.
“I saw a bright flash that I thought was lightning so I looked up and then I saw the orange fiery trail burning across the sky,” wrote a witness from Richmond Heights.
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“It was so cool!” wrote another observer from Belleville.
The AMS had also gathered three far-flung videos of “Event 5372” — from Missouri, Arkansas, and Illinois — showing the bright flash caught on camera.
“If we get enough reports, we can figure out a trajectory,” said Robert Lunsford, a fireball report coordinator for the AMS. “It looks like it headed right over you guys in St. Louis.
“These become visible at a height of about 50 miles,” said Lunsford. “At that altitude, it can be seen over several states.”
He said the object’s flight probably ranks in the “top 10%” of fireballs in terms of brightness. That could signify that it was bigger or faster than most chunks of space rock that encounter the Earth’s atmosphere.
“The brightness indicates the size,” said Lunsford. “The larger the object, the brighter, it’ll be. It also depends on velocity, too.”
Lunsford said the fastest fireballs are generally moving about 40 miles per second, but he estimated that Wednesday night meteor was going maybe 20 to 25 miles per second — or less.
But just because the flash was bright doesn’t mean a massive object was hurtling toward the Earth. Objects just the size of a softball or tennis ball can produce lots of light when they incinerate in the atmosphere. And a 2019 fireball that lit up the sky above St. Louis was estimated by NASA scientists to be about the size of a basketball.
If was unclear if Wednesday’s fireball was flying solo or not. Lunsford said it could be “a leftover” from the Perseid meteor shower that’s still active until the end of the month. But “most fireballs we see are just totally random, (and) not associated with any known shower.”
When fireball sightings occur, they typically set into motion a chain of analysis from both scientists and meteorite hunters who doggedly search for the coveted rock from space — solar system souvenirs that are about 4.5 billion years old, said Ryan Ogliore, an assistant professor of physics at Washington University who studies material from space.
Though hard to find, he said “fresh falls” of meteorites are important for scientists to retrieve quickly, when they’re the most pristine.
Some scientists said that early analysis suggested that Wednesday’s fireball didn’t quite make it to the ground, after its fiery trip through the atmosphere.
A few clues helped form that outlook, including the lack of observed fragmentation of the fireball breaking apart, or a sonic boom that can result from a solid object entering the atmosphere intact. Wednesday’s event also had a relatively short duration, compared to the fireballs that can end up touching down on terra firma.
“Usually things that drop meteorites last a little longer,” said Marc Fries, a cosmic dust curator for NASA.
After fireballs are reported, Fries uses weather data to try to decipher if, and where, anything might have landed on the ground. For instance, instrumentation used to map lightning strikes can also pick up the flashes from fireballs. And weather radar data can also help him tell if any meteorites might surface in specific areas.
But in his analysis Thursday, didn’t turn up evidence of the fireball seen over St. Louis.
“Basically, it wasn’t large enough to survive,” Fries concluded. “Made a beautiful fireball, though.”