The usual picture: gravity always pulls. But if a mass is in two places at once, like a double-exposure photograph, everything flips. Quantum theory allows a particle to be both there and here — literally. When we 'develop' this snapshot (that is, pinpoint where the object actually was) a test body feels a push away. No wind, just a quantum paradox.

This works thanks to weak negative values: a post-measurement rewrites the history of movement. It seems as if the very fabric of space bends backwards for an instant. An experiment with nanodiamonds will check if this is true, and help understand the quantum nature of ripples in space, dark energy, and black holes.