Bad news: The chances that an asteroid will take out your city are higher than you might think, according to a nonprofit group currently working on an asteroid-tracking telescope. "There is a popular misconception that asteroid impacts are extraordinarily rare," says Ed Lu, the former astronaut who heads the B612 Foundation. "That's incorrect." To make its point, the foundation released a video yesterday highlighting the 26 times an asteroid exploded in Earth's atmosphere between 2000 and 2013, Reuters reports. "An asteroid large enough to destroy an entire city hits the Earth, on average, once a century," says the narrator. The video, based on new data from the Nuclear Test Ban Treaty Organization, notes that some of the explosions had 600 kilotons of energy, Space.com reports—compare that to the 15 kilotons of energy in the nuclear bomb that leveled Hiroshima.
But the video's point is not simply to freak you out; the organization wants to sell you on its telescope idea, because right now we have no way of knowing when and where the next devastating asteroid will hit. Many of the aforementioned asteroids exploded high in the atmosphere or in remote locations, but that's just "blind luck," the narrator says. An early warning infrared space telescope could be used to track asteroids, and would spot them while they were still millions of miles and many years away from the planet, the video explains. NASA currently tracks larger asteroids, but an asteroid as small as 131 feet could level a city. The asteroid that exploded over Chelyabinsk, Russia, injured more than 1,000 people, and "taught us that asteroids of even [66-foot] size can have substantial effect," Lu says. (Read more asteroid stories.)