Massive meteor that exploded over Vermont had the force of 440 pounds of TNT

The meteor that exploded over the state of Vermont on the evening of March 7 was detected by ground-based seismometers, NASA has said. The space rock violently broke apart in Earth's atmosphere around 33 miles high, causing a shockwave that could be measured and heard by instruments

NASA revised its speed estimate on March 8 and said the meteor was traveling at around 42,000 miles per hour. This is more than 20 times faster than a rifle bullet, or 55 times faster than the speed of sound. The speed estimate was based on more than 100 eyewitness reports.

The space rock then hit the Earth's atmosphere, where air resistance caused pressure to build up ahead of the asteroid at the same time as a vacuum was formed behind it.

This pressure difference caused the meteor to violently explode with the force of around 440 pounds of TNT. Local reports say the force was felt by those on the ground, while a boom was also heard.

NASA said: "Such a pressure wave can also couple into the ground, causing minor 'tremors' that can be picked up by seismic instruments in the area."

NASA Meteor Watch said the object was likely a fragment of an asteroid, while the tremors witnesses reported were caused by a pressure difference between the front and back of the object.

Local news station WCAX3 reported calls from all over the state after the event, with Vermonters describing a "loud boom and body-rattling vibration" as the meteor passed overhead