It's the stuff of science fiction: An asteroid enters the Earth's atmosphere and destroys an entire city. However, the far-fetched scenario is apparently a very real possibility.
Click here to watch Andrew Pereira's report.
According to a new report by the nonprofit B612 Foundation, 26 asteroids tumbled into the planet's atmosphere from 2000 to 2013 and most could have caused major damage. The explosions they created ranged in strength from one kiloton to 600 kilotons. As perspective, the atomic bomb dropped on Hiroshima during WWII was 15 kilotons.
"Most of these asteroids exploded at very high altitudes so they weren't necessarily going to do as much damage as was done in Hiroshima, but there's no guarantee," Ed Lu, former astronaut and CEO of the foundation, said in a telephone interview from San Francisco.
The asteroids that reached Earth during the 13 year period were discovered by an array of infrasound sensors deployed around the globe to detect nuclear detonations. Seven of the asteroids exploded over the Pacific Ocean. The B612 Foundation created a two-minute video on its website to highlight the potential danger.
"The general public hasn't been aware of this, but that was the whole idea, to show people where and when these things happen," said Lu. "The scientific community has known about this for quite some time, but unless you can actually see it, it doesn't seem real for most people."
In February, 2013, the world watched in awe as a fireball raced across the sky over Chelyabinsk, Russia. What at first was thought to be a meteor was actually an asteroid that exploded with a force of 600 kilotons.
"Luckily it was outside of the city of Chelyabinsk, otherwise it would have been very bad," said Lu.
The potential for a city-killing asteroid is why the B612 Foundation is trying to get funding for its Sentinel project -- a telescope placed in orbit around the sun that would do a much better job at asteroid detection than earthbound optics.
"It costs about as much to finance this project as (it costs to build) a large freeway overpass or a small shopping mall," said Lu.
But unlike other space initiatives, the foundation is not asking for help from the U.S. government or other countries. B612 representatives say it's the responsibility of everyone living on Earth to take Sentinel from the drawing board to an actual orbit around the sun. The foundation solicits donations from the public on its website.
"I see the whole world really as not just traveling on spaceship Earth, we're the crew," B612 program architect Scott Hubbard said on the foundation's website. "We're the crew members for planet Earth and we have a stewardship responsibility."
By placing a telescope around the sun, Lu said humans could prevent an asteroid from hitting the Earth and possibly destroying an entire city.
"You simply run into it with a small spacecraft, and you just change its trajectory by a tiny amount," said the former astronaut. "Remember that you're going to deflect these things many years and many millions of miles before they hit the Earth."
Lu said an extinction-level asteroid hits the Earth every half million to one million years on average, but the next big one could be prevented.
"We're looking for people who want to change the future of planet Earth and people should know that it's actually for individuals to do that."