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.
That raises an obvious question: if we find an asteroid heading our way, what should we do next? Last month, NASA launched the Double Asteroid Redirection Test (DART) mission to test one idea. This involves crashing the spacecraft into an asteroid to change its course. Other options include attaching thrusters to the asteroid ...
