Better to blow up an Earth-bound Asteroid?

Should we blow up objects on a collision course with Earth? Or will they do less damage left intact? More importantly, is there a gene for hating marmite? And what makes copper such a good conductor? How would a caveman cope in modern society? What's the secret to how balls spin in sport, and why does wrapping vaccines and antibiotics in silk make them last longer. Plus, why physics says Batman's cape won't work... Like this podcast? Please help us by supporting the Naked Scientists