It is a chilling prospect. At some point, the universe faces a cold and haunting future. Its entropy, or disorder, is always increasing and when it peaks, energy will no longer be able to flow, making life and almost everything else impossible. By this time, black holes will have evaporated and ever-accelerating expansion will have blown galaxies apart. All that remains will be a uniformly cold, dark, diffuse expanse.

According to the laws of thermodynamics, this dismal picture, called the heat death of the universe, is unavoidable. Now Nobel laureate Frank Wilczek, a theoretical physicist at the Massachusetts Institute of Technology, has hatched a survival plan. He reckons a hypothetical device he calls a time crystal could power a computer that would keep on running long after everything else has succumbed to the pull of entropy.