Study: ‘City Killer’ Asteroids Found To Be More Rare, But 3.15 Million Are As Big As The Chelyabinsk Meteor

We are being warned constantly that the next catastrophic asteroid or comet strike could come at any time, but a new study indicates that there are about 10 times fewer “city killer” asteroids hurtling through space than had been previously estimated. Still, the actual number of potentially deadly Near-Earth Objects (NEOs) is still astronomically high. Unfortunately, so is the large percentage of those dangerous space missiles that are as large as the Chelyabinsk meteor that detonated and disintegrated in the skies of Russia in February 2013, an explosion that released energies equivalent to an estimated 10 times that of the atomic bomb dropped on Hiroshima, Japan, in World War II.

The Chelyabinsk meteor was the size of a large house.

According to Space Daily, a study conducted with the Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile found that there are approximately 3.5 million NEOs in orbit inside our Solar System, a considerably lower number than the roughly 35 million earlier studies had calculated. The study’s lead investigator, Lori Allen, who is Director of the Kitt Peak National Observatory in Arizona, notes that, of the down-sized estimate, 90 percent are believed to be about the size of the Chelyabinsk meteor, which measured an estimated 17 meters (58 feet) in diameter.

“There are around 3.5 million NEOs larger than 10 meters, a population 10 times smaller than inferred in previous studies.

“About 90% of these NEOs are in the Chelyabinsk size range of 10-20 meters [33 – 66 feet].”

But the smaller estimate in no way minimizes the threat of direct asteroid strike by one of the NEOs. And the 90 percent that are Chelyabinsk-sized is equivalent to roughly 3.15 million dangerous space rocks that could have the potential to be catastrophic city killer asteroids. (Congress, according to Stanford University physicist Richard Blandford in an Op-Ed written for Space News, labels objects 140 meters (459 feet) and smaller “city killers.”)

The Chelyabinsk meteor exploded about six miles above ground, but the subsequent shockwave caused minor building damage, especially concerning shattered window glass, and saw over a thousand people seeking medical attention in the city of Chelyabinsk and several surrounding cities. The meteor went totally undetected until just before detonation, entering the Earth’s atmosphere from a line-of-sight trajectory with the Sun.

As a point of comparison, the 1908 Tunguska Event, which is believed to have been caused by a 45-meter (148 feet) object, leveled a thick forest in south-central Siberia roughly the size of New York City.

The asteroid study derived its findings from a single observational data set that included no external model assumptions, according to Space Daily. The NEOs ranged in size from 1 kilometer (3,281 feet) down to 10 meters (33 feet). It is slated for publication in the Astronomical Journal.

A separate independent study published earlier this year was conducted by Pasquale Tricarico, Senior Scientist at the Planetary Science Institute in Tucson, Arizona, analyzed multiple data sets showed similar results regarding the down-sized meteor and asteroid population.

The Tunguska and Chelyabinsk meteors have demonstrated that NEOs the size of a house or a large multi-story building have the potential for catastrophic destruction. The Inquisitr reported on a study of nearly 37,000 asteroids in March that used an impact calculator that revealed the possible extent of devastation that might be incurred by asteroid impacts of varying sizes on major U.S. cities. It found that an asteroid measuring just 100 meters (328 feet) across that, if its point of impact was New York City, would level buildings for a radius of over two miles and kill over 2.5 million people.

[Featured Image by Vadim Sadovski/Shutterstock]