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Modern physics has two stories to tell about our universe. The first says it’s basically made of space-time. It’s a continuous stretchy fabric that’s been puffed up since the dawn of time. .
Both stories are compelling and describe what we observed with incredible accuracy. The big difference, however, is the scale at which they apply. Albert his Einsteinian theory of general relativity, which describes gravity, space and time, governs very large bodies and cosmic distances. Quantum physics, on the other hand, dominates tiny, energetic atoms and subatomic particles.
Ultimately, both stories cannot be true. Nowhere is this more evident than at the Big Bang, when all of the universe was compressed into a very small point. Here we need a single theory that includes gravity and the quantum realm. “The big question is why are we here,” says Toby Wiseman, a theorist at Imperial College London. “Quantum gravity seems to be the only answer.”
Alas, despite decades of searching, it’s still the answer we haven’t found. Quantum gravity means harmony between continuity and indivisibility, predictability and randomness. I have a lot of ideas, but I can’t fully incorporate them all. “We have not yet succeeded in understanding the beginning of space and time,” says Wiseman.
Most physicists attempting this start with quantum physics, with quantum field theory at its core. This accounts for “quantizing” three of his four forces of nature (the electromagnetic force, the strong nuclear force, and the weak nuclear force) as the elementary particles that carry the force. that …
