Reality Is Not What It Seems: The Journey to Quantum Gravity

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   Spacetime is not a passive backdrop but a quantum entity with a granular, discrete structure at the smallest scale.

   Reality Is Not What It Seems: The Journey to Quantum Gravity · 2014

   Space-time is a granular quantum entity, not a passive background.

   Rovelli explains loop quantum gravity, where spacetime is made of interwoven quantum loops. At the Planck scale, about 10^-35 meters, space becomes granular, and time disappears as a fundamental variable. For instance, an atom of space cannot be divided further. This means there is no universal time, only relations between events. The theory requires no background, unlike general relativity. Rovelli emphasizes this is a hypothesis, not experimentally confirmed, but it offers a coherent picture of the universe at the quantum scale.

   “Space and time are no longer a fixed background on which events unfold. They are themselves dynamical entities, which fluctuate and become quantized at the Planck scale.”

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