What Scares You?

Some things are pretty certain. There's a very good chance you will stub your toe causing great temporary pain sometime within the next 70 years. But what are the chances a black hole will swallow the earth in that time or that terrorists will blow you up or that humans will evolve to extinction between now and 2075?

You could lie awake obsessing about that... or you could check out the Guardian who have polled some top scientists about what scares them.