Half-ton meteor exploded in US skies on New Year

A meteor that caused a loud bang, heard in western Pennsylvania on the first of the year, exploded into the atmosphere with a force equivalent to 30 tons of TNT, according to NASA.

The sounds were heard a few minutes before 11:30 am (local time) last Saturday. If the sky hadn’t been cloudy, the meteor would have been easily visible as it exploded, according to a post on the NASA Meteor Watch page on Facebook. A NASA estimate indicated that the explosion’s brightness would have been equivalent to 100 times that of the full moon.

A nearby infrasound station recorded the wave of the meteor’s explosion, which allowed NASA to estimate the dissipated energy.

“If we make a reasonable assumption about the meteor’s speed (about 45,000 miles per second [72,4 mil quilômetros por hora]), we can estimate the size of the object in one yard [pouco menos de um metro] in diameter, with a mass close to half a ton”, stated NASA.

Allegheny County, which includes the city of Pistsburg, received 911 complaints on Saturday of a loud bang and shudder in the South Hills suburb, according to the county’s official Twitter feed. Earthquake, thunder and lightning were initially ruled out as possible causes.

A sonic boom, which sounds similar to an explosion or thunder, happens when an object (such as a meteor or supersonic aircraft) moves through the atmosphere at a speed faster than the speed of sound.

Air reacts like fluid to supersonic objects, NASA said. As these objects pass through the air, molecules are pushed to the side with great force, forming a shock wave, which is heard as a sonic boom.