A top NASA asteroid scientist has said that the best way to defend the Earth from asteroids is to build a new telescope capable of spotting them as soon as possible.  

Dr Amy Mainzer from NASA's Jet Propulsion Laboratory in Pasadena, California, said that trying to spot asteroids with current telescopes was like trying to spot a 'lump of coal in the night's sky'. 

Her team has proposed a new system designed to spot large meteors capable of causing significant damage.  

It would identify incoming asteroids capable of causing huge loss of life - just like the meteor which wiped out the dinosaurs 66 million years ago. 

They claim this would give the scientists more time to come up with a strategy to intercept the rock.