"Some say the world will end in fire; Some say in ice…", so reads the first line of the poem Fire and Ice by Robert Frost, and it is a fine introduction to the Nobel Prize in Physics 2011. What is the ultimate fate of the Universe? Probably it will end in ice. This year's Laureates studied several dozen exploding stars, called supernovae, in faraway galaxies and have discovered that the expansion of the Universe is speeding up. The accelerating expansion of the Universe is one of the greatest enigmas in physics today.