A single particle can be in two places at once — that's superposition. But any interaction, like a shout, instantly 'collapses' this uncertainty. It was long thought that even gravity could interfere. Following the ideas of Roger Penrose and John Wheeler, physicists have finally rigorously described the effect: gravity itself destroys superposition. But how weakly!

Ordinary collisions with air molecules for a quantum state are like the clang of a blacksmith's hammer. Gravity, on the other hand, is a barely perceptible whisper in a quiet room. To hear it, almost perfect isolation is needed. And here's the main surprise: this whisper grows with distance surprisingly lazily. For instance, by expanding a superposition from a meter to a kilometer, you amplify the gravitational noise only a few times, not a thousand. The accumulated effect is almost indistinguishable — like an echo that, as it spreads, barely changes its intensity.

This sets a fundamental limit for quantum technologies. Someday, ultra-precise detectors hunting for gravitational waves will hit this barely noticeable rumble. And then the quietest sound of nature will become the only thing hindering us. The irony is that the weakest of all forces will turn out to be an insurmountable wall.