turn left. 'Think of ten-pin bowling. If the ball swerves a bit just before it hits the front pin, it still makes the strike. But if the angle's slightly wrong when it leaves your hand, it veers off more and more as it rolls down the lane. A little drift becomes a big one over time and it misses most of the pins.' She hesiated and then smiled weakly. 'There's your car crash as well. If you'd seen the parked car soon enough, you could've swerved round it. But you left it too late. You couldn't swerve enough and slammed into it.'
That was something Josh could understand. He nodded.
I li's mum sighed.
'Pity the Earth hasn't got an air bag to stop us all getting hurt.
'I low big a bomb is it?' Dave asked, always keen to talk about weapons.
'The biggest ever built,'Josh's mum replied. 'You can blast a hole in an asteroid or-like we're doing explode a bomb just above its surface. Either way, some