Part of the show Naked Science Q&A and the Science of Happiness
Pat in Lowestoft asked:
If everything on the planet got wiped out by a bomb, could life start again like it did originally?
I think you'd have to try really hard to wipe out life. There's life thriving in the most inhospitable places on our planet including right down in the deep ocean trenches, in hot vents and volcanoes. I think it would be pretty impossible to wipe out life. Over the last few years people have found bacteria living kilometres down in solid rock, so you'd have to vaporise a couple of kilometres of rock. The best example must be the huge meteorite several kilometres across slammed into the Earth about 60 million years ago. It dispensed with the dinosaurs but not crocodiles, which were around at the same time as the dinosaurs. It meant the certain animals were set back a long way but meant that animals like us, mammals, began to flourish. It gave us our big break in life. So perhaps if we did decimate the Earth with a bomb, then maybe another funny form of life would take over.