Uncertainty principle

The uncertainty principle was formulated by the German physicist Werner Heisenberg, who published the idea in a paper in 1927. It states that there is a fundamental limit to how precisely certain pairs of properties of a particle, such as its position and its momentum, can be known at the same time. Mathematically, the product of the uncertainties cannot be smaller than a very small constant related to Planck's constant. The principle is not merely a result of clumsy measurement, but arises from the wave nature of matter in quantum mechanics. It marked a break from classical physics, which assumed that nature was fully predictable. Niels Bohr and Heisenberg discussed its meaning, while Albert Einstein remained uneasy about it.

Open on the timeline