What is the double-slit experiment, and why is it so important?

The Double-Slit Experiment Just Got Weirder: It Also Holds True in Time, Not Just Space

The Quantum Brief on Instagram: "Part 2 | The Double Slit Experiment When particles like electrons or photons are fired one at a time toward a barrier with two slits, they create an interference pattern on the detector screen, just as waves would. This suggests that each particle passes through both slits simultaneously, behaving like a wave. But the crazy part is that if scientists place a detector to observe which slit the particle goes through, the interference pattern disappears, and they be