KentuckyFC writes "One of the central concepts in quantum theory is wave-particle duality — that every object can be thought of as a particle and a wave. Indeed every object has a quantum wavelength associated with it and so can form a quantum superposition with itself. That's easy to demonstrate with fundamental particles such as photons and electrons by passing a beam of them through a double slit and watching the interference pattern that forms on the other side. In this way, physicists have observed the interference patterns associated with atoms and even molecules such as buckyballs. Now, a group at the University of Vienna has observed the interference pattern formed by the quantum superposition of molecules containing over 800 atoms, or around 5,000 protons, 5,000 neutrons and 5,000 electrons. That's the most macroscopic occurrence of wave-particle duality ever observed, they say."