The 26 asteroids were identified by listening devices manned by the Comprehensive Nuclear Test Ban Treaty Organization -- a global detection network created to keep an ear out for unauthorized nuclear weapons testing. The impact explosions ranged in strength from one to 600 kilotons.
"To put that in perspective, the atomic bomb that destroyed Hiroshima in 1945, exploded with an energy impact of 15 kilotons," the B612 Foundation pointed out in a press release.
Of course, most of the 26 asteroids exploded high enough up in the atmosphere that human life was never at risk. But one, the February 15, 2013, impact over Chelyabinsk, Russia, rattled buildings, shattered thousands of windows, and sent more than 1,000 people to the hospital.
"There is a popular misconception that asteroid impacts are extraordinarily rare ... that's incorrect," explained former astronaut Ed Lu, founder of the B612 Foundation.
Lu's organization, which is comprised of other astronauts and scientists, contends that humans need to start developing strategies and technologies to detect and deflect potentially city-crushing asteroids.
As of right now, Lu said, "the only thing preventing a catastrophe from a 'city-killer' sized asteroid has been blind luck."