16/04/2026
Quantum mechanics has a rule that bothers everyone who encounters it.
Particles don't have definite positions until you measure them. Before observation, they exist in superposition — spread across multiple locations simultaneously, interfering with themselves like waves, following no single definite path.
This has been confirmed for electrons, atoms, and small molecules. But those are small. Electrons are essentially dimensionless points. Atoms are almost nothing. Surely, at some scale — surely, for something large enough to see, or weigh, or call a "lump of metal" — classical physics takes over and things start behaving normally.
Researchers at the University of Vienna just tested that assumption.
They created clusters of 5,000 to 10,000 sodium atoms — nanoparticles 8 nanometers across, heavier than most proteins, containing more atoms than most people's intuition about quantum behavior allows. Then they sent these clusters through a series of laser diffraction gratings designed to place them in quantum superposition.
The particles produced clear quantum interference patterns.
They did not have single defined positions while in flight. Their quantum spread was many times larger than their physical size. They were, in the language of the experiment, simultaneously here and not here — Schrödinger's metal lump, in two places at once, interfering with themselves.
"Intuitively, one would expect such a large lump of metal to behave like a classical particle," the lead author noted. "The fact that it still interferes shows that quantum mechanics is valid even on this scale."
The boundary between the quantum world and the everyday world — the line where physics stops being strange and starts being normal — was not found where they looked.
It may not exist at all. ⚛️