Just how powerful was that massive meteor that rocked Russia last February? This powerful: The resulting shock wave circled the Earth twice, reports the BBC. Scientists reached the conclusion after examining data from global stations that measure low-frequency acoustic waves, reports Discovery. This is the first time they've seen such a thing since the International Monitoring System—designed to pick up evidence of nuclear tests—went into effect, notes the Independent.
“For the first time since the establishment of the IMS infrasound network, multiple arrivals involving waves that traveled twice round the globe have been clearly identified,” writes a researcher in the journal Geophysical Research Letters. The team also confirmed that this was the biggest space impact since the 1908 Tunguska meteor. The more recent incident released the energy equivalent of 460 kilotons of TNT, or 30 Hiroshima bombs, into the atmosphere. (Tunguska was a lot bigger—10 to 15 megatons.)