Many ideas have been proposed to deal with an NEO should one be detected on a collision course with Earth. Despite the popular image in the movies of an asteroid or comet being destroyed in a huge explosion, most people favour the idea of simply changing a threatening object’s orbit. Proposals include the use of solar sails, attaching engines and even changing the colour of certain areas of the object to take advantage of the force exerted when the Sun’s light is re-radiated back into space.

Whatever the method, there is broad agreement that the priority is to catalogue as many objects as possible so we can identify any real threats. In parallel with this cataloguing, many argue that we must start to develop and test the necessary technology so we are prepared.

In addition to developing a method for deflecting a dangerous NEO, it is also important to have international agreement about how to respond to such an emergency. Rusty Schweickart, a former Apollo astronaut and founder of the Association of Space Explorers, has been campaigning for the international community to develop protocols for dealing with such an incident. He believes it is essential to reach agreement before we are faced with a real situation, thus avoiding the political complications that could accompany a real-life threat.