A fireball spotted by numerous eyewitnesses above Vermont on 8 March was travelling at a speed of about 19 kilometers per second, according to NASA Meteor Watch.
In a Facebook post, the group argues that the fireball was likely a fragment of an asteroid, that fragmented in the atmosphere when "the pressure difference between front and back exceeded its structural strength".
Having procured "infrasound measurements from 3 nearby stations", the group states that "the amplitudes and durations of the signals put the energy of the fireball fragmentation at 440 pounds (200 kilograms) of TNT".
Based on these calculations, NASA Meteor Watch also managed to estimate the mass and size of the object: 10 pounds (4.5 kilograms) and 6 inches (15 centimeters) in diameter, respectively.