Video of the September 21, 2012 UK fireball. At closest, the meteor was only 33 miles above the Earth’s surface.
On the evening of September 21 a spectacular fireball as bright as the full moon blazed over the British Isles fracturing into dozens of fragments. Traveling at 8 miles per second – barely enough to escape Earth’s gravity – the meteor took an estimated 3 minutes to cross the sky as it sizzled westward over the Atlantic. Because it lingered so long, some observers thought it might be the breakup of a satellite, but the great majority of satellites travel the opposite direction – from west to east – making a chunk of slow-moving space debris the better possibility. Most meteors strike the atmosphere between 11 and 72 miles per second.
155 minutes later another fireball tore across eastern U.S. and Canadian skies before incinerating itself. Were these two sightings connected? Esko Lyytinen, mathematician and member of the Finnish Fireball Working Group of the Ursa Astronomical Association, modeled the meteor’s flight and determined that its slow speed may have allowed it to be captured by Earth’s gravity.
After its British debut, the object orbited once around the Earth and flared to life again over Canada before finally breaking to bits. It’s unknown if pieces survived to land as meteorites. The original meteoroid, the name given a space rock before it enters our atmosphere, is estimated to have weighed from several to tens of tons. Most of it would have burned up miles high, turned to dust and vapor by the heat and stress of entry.
Footage of the Great Daylight Fireball of 1972
While pieces of the meteor did burn up over the North Atlantic, Lyytinen believes a surviving fragment skipped back into space to become a temporary satellite of Earth. Slowed to 5.7 miles per second by its atmospheric encounter, the meteoroid’s fate was sealed – it wasn’t going anywhere but down. After one orbit, it flared a final farewell in a fiery trail over Canada.
Lyttinen cautions that more study needs to be done to confirm his hypothesis. If proven true, this would be the first time a meteoroid has been observed to graze in and out of Earth’s atmosphere, becoming a temporary natural satellite in the process. For a brief few hours our planet had not one but two moons!
I wish to thank Dirk Ross and his excellent Latest Worldwide Meteor / Meteorite News website for background on the fall. Check out his site as well as science writer Kelly Beatty’s .informative article. Stay tuned for an update.