While general relativity is very successful in describing the gravitational interaction and the structure of space and time on large scales [205], quantum gravity is needed for the small-scale behavior. This is usually relevant when curvature, or in physical terms energy densities and tidal forces, becomes large. In cosmology this is the case close to the Big Bang, and also in the interior of black holes. We are thus able to learn about gravity on small scales by looking at the early history of the universe.
Starting with general relativity on large scales and evolving backward in time, the universe becomes smaller and smaller and quantum effects eventually become important.
Of course, I could've told you the same: Loop Quantum Cosmology happens all the time with the beer reserves (or depletion of) in my fridge. It's impossible to not take full account of the local -- at home -- beer supply.
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Also, I think this loop quantum cosmology happened to me in a bar once, where classical general relativity broke down as my glass of beer disappeared. I needed to modify and extend the theory, and place the singular empty glass into context with the broader scene: by this I tried to modify the small length scale of my empty beer with the high curvatures of some babes, thus proving that the surrounding space-time could be modified, and a good time could be continued.
It's kind of a return to the late Clifford Geertz: context, context, context. Afterall, middle fingers don't happen in vacuums, and the extreme local is worth our attention.
Try studying Ricci curvature and the Ricci flow.
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