NASA this week entreated amateur astronomers the world over in helping to identify the smaller asteroids lurking about space that could wipe out a city or worse upon impact with Earth.

The U.S. space agency has reportedly coined the initiative, “The Asteroid Grand Challenge,” which focuses on asteroids 30 to 40 meters in size, rather than the bigger, planet-busting behemoths that, for the most part, have already been discovered, and which scientists believe wiped out the dinosaurs millions of years ago.


"What we need to do is increase the frequency of identification of asteroids such that we can also track them and characterize them," Brian Muirhead, NASA’s chief engineer, told National Geographic.

Scientists estimate as many as 95 percent of asteroids larger than 1 kilometer have already been found, but that, conversely, 99 percent of the smaller, 30 to 40 meter variety near-earth-objects, or NEOs, are yet to be discovered.

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NASA issued the challenge four months after an 18-meter-long NEO reportedly exploded above Russia, injuring more than 1,000 people, and another asteroid, which Reuters characterized as “the size of a small truck,” missed Earth by a margin measuring less than the distance to the moon.

"This was a wake-up call for the world on the threat near-Earth asteroids can pose for the human population," Ed Lu, a former NASA astronaut, told National Geographic. Lu is chief executive of B612, a nonprofit agency that has worked for years to raise awareness about asteroid threats.

Earlier this year, the U.S. House of Representatives’ science committee held a hearing that, according to Reuters, focused on “Threats from Space" or the nation’s efforts to date to identify NEOs.

Click for the story from National Geographic.