Apparently, I am absolutely fundamental to the continuance of life as we know it. Completely irreplaceable. The Earth simply could not rotate without me. In fact, every time I drift off to sleep, the planet plaintively calls out, "Mum! MUM!" and I have to stagger in to push its axis up to speed again. "Remember to tilt at 33 1/3 degrees," I mumble as I stumble back to my bed and collapse asleep, secure in the knowledge that I've saved the world - again.