The End of Everything

An engaging read for the general audience about what we currently know about the history and structure of the universe and what that knowledge -- and the pieces we don't know -- might mean for its future and eventual end. Katie Mack writes in a casual, entertaining style. It's clear she finds all of this absolutely fascinating. And she sprinkles the writing with funny stories and quotes and side notes to get across the basics of quantum mechanics, Higgs fields, high-energy physics and the like without delving too much into the math. But the math, and the measurements, are important, because as it turns out, very small changes in how things work at the quantum level can have major implications on the universe's ultimate fate.

The last time I read about this topic in anything resembling depth was about a decade ago. Since then there've been major discoveries in both quantum physics (chiefly confirming the existence of the Higgs boson) and astronomy, where we've found ways to look at ever more distant galaxies, and effectively farther and farther back in time.

Dr. Mack goes through the easier to grasp possibilities first, the ones based on what we do know about the universe. Big crunch, heat death, big rip - these are almost tangible, and which is more likely depends on things we can measure right now. Then she gets into the more esoteric possibilities, the ones based on the uncertainties. Like, if this quantum field we've measured is a little bit off one way or the other, reality might be unstable, so it would be really helpful to get better measurements. Or some of the multidimensional theories that have been proposed to unify relativistic gravity with quantum mechanics. If our 3D universe is just one of many in a larger-dimensional space, colliding with another one would probably be bad news for both!

She finishes up with a quick round-up of upcoming lines of research and some new theories in development that could fill in the gaps, or could shift to a new paradigm. (One theorist she spoke to suggested that even space and time might not be fundamental aspects of the universe, but built on something else)

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