In 1930, German Theoretical Physicist Werner Heisenberg Came Up With A Thought Experiment, Now Known

Physicists find a way to probe the quantum realm without wrecking everything

Finally...!

In 1930, German theoretical physicist Werner Heisenberg came up with a thought experiment, now known as Heisenberg’s microscope, to try to show why it’s impossible to measure an atom’s location with unlimited precision. He imagined trying to measure the position of something like an atom by shooting light at it.

Light travels as a wave, and Heisenberg knew that different wavelengths could give you different degrees of confidence when used to measure where something is in space. Short wavelengths can give a more precise measurement than long ones, so you’d want to use light with a tiny wavelength to measure where an atom is, since atoms are really small. But there’s a problem: light also carries momentum, and short wavelengths carry more momentum than long ones.

That means if you use light with a short wavelength to find the atom, you’ll hit the atom with all of that momentum, and that kicks it around and risks completely changing its location (and other properties) in the process. Use longer wavelengths, and you’ll move the atom less, but you’ll also be more uncertain about your measurement.