The meteor that struck Russia near the Ural Mountains earlier this month was a record-setter here on Earth, the largest meteor to impact our planet in 105 years. But it's actually run of the mill in cosmic terms, and there are millions more where it came from, according to several groups of scientists who have traced the Russian meteor back to its starting point in our solar system's main asteroid belt.
"There are millions more just like it."
"There are millions more just like it," said William Cooke, lead scientist at NASA's Meteoroid Environment Office, in a post about the meteor's origins on NASA's Science website published Tuesday. Cooke and other NASA scientists believe the Russian meteor came from the main asteroid belt, a donut-shaped ring of asteroids, most of which are located between the orbits of Mars and Jupiter.
Above, a NASA diagram showing the asteroid belt relative to Earth's orbit (blue) and that of Mars (red) and Jupiter (purple). The red dots are those asteroids that pass close to Earth.
Thousands of these asteroids cross into Earth's orbit, but not all are a danger: NASA recently released a survey from its infrared WISE space telescope estimating there are about 4,700 of these near-Earth asteroids that are "potentially hazardous," or large enough to survive entering the planet's atmosphere and capable of doing damage. Unfortunately, only 20 to 30 percent of these had been found as of the middle of 2012.
NASA estimates 4,700 potentially hazardous asteroids
Separately, two scientists in Colombia used publicly available dashcam and security camera footage of the recent Russian meteor fragments streaking through the sky to pinpoint its origin in a specific group of about 240 near-Earth asteroids known as the Apollo family. That could mean it was a close cousin of the last big meteor to impact Earth, the Tunguska meteor, which also impacted Russia back in 1908 and has been traced back to the same asteroid grouping.
The Colombian analysis noted that the 2013 meteor fragmented into many pieces when it entered Earth's atmosphere, including a large one that is thought to have left a hole in the ice on a lake in Russia's Ural Mountains near the city Chelyabinsk. Locals and tourists have been scouring the area nearby to try and find the fragments, with some success. About 100 fragments have been confirmed by authorities, including a 2.2 pound fragment just found, and divers recently spotted holes in the lakebed that they think were made by meteor fragments as well.