How NASA’s asteroid smashing technology could save YOU from a painful death

When NASA managed to smash a satellite into an asteroid last week, people across the world rejoiced that humanity could be saved if a huge space rock heads for earth. 

But will it really work if a planet-killing asteroid like the six-mile-wide one that wiped out the dinosaurs is about to hit our planet? How much notice will NASA scientists need? And will they need nuclear weapons. 

This is MailOnline’s video guide with the answers.