Every day, about 25 million flaming meteors enter the Earth’s atmosphere. Most burn up almost immediately as they fall, leaving behind millions of kilograms of space dust. But fortunately for eager astronomers, some meteors can resist fatality — at least long enough to flash brightly in the sky and leave a streak of glowing hot air in their wake. On Thursday, people in Russia witnessed one of these dazzling events and captured it on camera.
Citizen scientist and Russian amateur astronomer Roman Tkachenko collected footage of the fireball as seen from the cities of Kursk, Lipetsk, Voronezh, and Orel. At 4:15 am local time, the brightly burning meteor zoomed overhead and quickly exploded. According to the International Meteor Organization, many witnesses reported hearing a loud sonic boom. You can see the it all happen in the video below, 13 seconds in.
While video footage of the fireball is amazing evidence of its zoom through the atmosphere, its entry was detected by the International Monitoring System(IMS) — a network of 321 monitoring stations whose main purpose is to detect nuclear weapons tests. This fireball was detected by at least nine stations in infrasound because the penetration of a meteorite through the atmosphere generates infrasound waves of a very low-frequency content. These waves, in turn, can be detected by the infrasound sensors of the IMS.
According to NASA data collected and analyzed by the International Meteor Organization, the meteor’s source energy was the equivalent of about 3.2 kilotons of TNT, “which corresponds to an entering asteroid of about four meters diameter.” Asteroids are the large rock bodies that reside in our Solar System. If they break into smaller chunks, they’re called meteoroids, and when a meteoroid enters the Earth’s atmosphere and vaporizes, it’s called a meteor. If any of the original rock body survives and falls to the Earth’s surface, then it’s called a meteorite.
At four meters (13 feet) in diameter, this was a little guy as far as asteroids go. For comparison, the Chelyabinsk asteroid that blasted over Russia in 2013 was 65 feet in diameter and caused considerable damage.
While the IMS detected the fireball once it hit the atmosphere, that initial detection still came as a surprise. Scientists hadn’t detected it prior to its entry through the atmosphere, likely because of its small size. In terms of objects that may threaten Earth if they come crashing down, NASA is primarily concerned with documented near-Earth objects (NEOs) more than 459 feet in diameter because those are expected to do a lot of damage even after burning up in the atmosphere.
According to a new NASA report on its plan to prevent a NEO-based catastrophe, the agency has almost more than tripled the number of NEOs it has catalogued since it began the job in 2005. That’s good news for anyone trying to stay aware of an impending Armageddon situation — but it means tinier fireballs like Russia’s meteor will keep surprising local residents.