Asteroids represent an existential threat to humankind. A collision with a 10 kilometer-sized asteroid led to the demise of the dinosaurs some 65 million years ago. Astronomers expect other collisions with asteroids about 1 kilometer across every 500,000 years or so.
Which is why NASA and other space agencies are attempting to map the population of Near Earth Asteroids. Today, just 40 per cent of these have been spotted. But the goal is to build a complete picture of the threats from asteroids down to a few tens of meters in size, within the next few decades.
