On the 4th, physicists from University College London (UCL) proposed an astonishing theory in two papers published in Physical Review X and Nature Communications, which unifies gravity and quantum mechanics while preserving Einstein's classical concept of spacetime. Modern physics is built on two pillars: one is quantum theory, which controls the smallest particles in the universe; Another is Einstein's theory of general relativity, which explains gravity through the curvature of spacetime. But these two theories are contradictory and have been difficult to reconcile for over a century. The common assumption is that Einstein's theory of gravity must be modified or "quantized" to adapt to quantum theory. But the post quantum theory of classical gravity proposed by the research team in Physical Review X challenges this hypothesis and suggests that spacetime may be classical, meaning it is not governed by quantum theory at all. The new theory is not about modifying spacetime, but about modifying quantum theory and predicting the inherent collapse of predictability mediated by spacetime itself. This will cause random and violent fluctuations in spacetime, with amplitudes greater than those imagined by quantum theory. If the measurements are accurate enough, the apparent weight of the object will become unpredictable. The paper published in Nature Communications proposed an experiment to test the theory: measuring mass very accurately and observing whether its weight fluctuates over time. Research has shown that if spacetime does not have quantum properties, then there must be random fluctuations in the curvature of spacetime, which have specific characteristics that can be verified through experiments. Although the experimental concept is simple, the weighing of objects requires extreme precision. The study elucidates a clear relationship between two measurable quantities - the scale of spatiotemporal fluctuations, and how long objects such as atoms or apples can remain in quantum superposition at two different positions. The starting point of this theory is that researchers are attempting to solve the problem of black hole information. According to standard quantum theory, the information of an object entering a black hole is not destroyed, but this violates general relativity (which states that objects crossing the event horizon of a black hole can never be understood). Due to the fundamental collapse of predictability, the new theory allows information to be destroyed. (Lai Xin She)