The End of Everything, Katie Mack

"We don't know yet whether the universe will end in fire, ice, or something altogether more outlandish. What we do know, is that it's an immense, beautiful, truly awesome place, and it's well worth our time to go out of our way to explore it. While we still can."

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"Whether or not we subscribe to any particular religion or philosophy, it would be hard to deny that knowing our cosmic destiny must have some impact on how we think about our existence, or even how we live our lives. If we want to know whether what we do here ultimately matters, the first thing we ask is: how will it come out in the end? If we find the answer to that question, it leads immediately to the next: what does this mean for us now? Do we still have to take the trash out next Tuesday if the universe is going to die someday?"

p. 4

"We're definitely getting closer to an answer. Whether or not the world is at any given moment falling apart from a political perspective, scientifically we are living in a golden age. In physics, recent discoveries and new technological and theoretical tools are allowing us to make leaps that were previously impossible. We've been refining our understanding of the beginning of the universe for decades, but the scientific exploration of how the universe might end is just now undergoing its renaissance."

p. 7

"One of the great validations of the Big Bang theory is the fact that we find a close match between our observations in the cosmos and the calculated abundance of elements we expect from the Big Bang based on our estimates of the temperature and density of that primordial fireball. The agreement isn't perfect--there's some lingering confusion around the lithium abundance that may or may not be telling us about some extra weirdness going on in the early universe--but with hydrogen, deuterium, and helium, measuring how much we actually see out there and comparing it to what we calculate should happen if you shove the entire cosmos into a nuclear furnace results in some absolutely beautiful concordance."should happen if you shove the entire cosmos into a nuclear furnace results in some absolutely beautiful concordance.should happen if you shove the entire cosmos into a nuclear furnace results in some absolutely beautiful concordance."

p. 45

"You could argue that these scenarios are not exactly the same thing. The quantum fluctuation that re-creates your experience of stubbing your toe might produce something that is exactly like you in every detail, but you, as an entity, would have been long dead by then. But this brings up questions of what it means to be you. Is the exact configuration of atoms you, or is there something ineffable and persistent about your consciousness that could never be re-created piece by piece?"

p. 101

"You might think this would be the end of the Sun--depleted, transformed, and planet-devouring, left with no fusion reactions available that are strong enough to hold it up. Fortunately, there's a kind of pressure even stronger than fusion reactions that can keep the post-red-giant Sun and other stars like it from collapsing entirely, allowing it instead to live our its convalescence as a white dwarf star. And this pressure comes directly from quantum mechanics."

p. 121

"Symmetry isn't just about whether or not something looks the same in a mirror. In physics, it's all about patterns, and how those patterns can give you deeper insight into some underlying structure."

p. 137

"Whether or not you trust early universe theories, taking vacuum decay seriously depends on placing a great deal of trust in the Standard Model of particle physics, which we know cannot be the whole story. Dark matter, dark energy, and the incompatibility of quantum mechanics and general relativity all point to there being something more to the universe than what we can currently write down. Whatever comes along to replace the Standard Model might, by the by, save us from even having to vaguely worry about a wayward bubble of quantum death."

p. 155

"We've known for a long time that something has to be wrong with gravity. It works too well. Einstein's general relativity has so far performed perfectly in every situation in which it's been rested. For decades, physicists have tried to find some kind of deviation, somewhere, anywhere, that would show us how the simple equations written down in Einstein's theory inevitably break down. Somewhere, in some extreme regime, like at the edge of a black hole or among the particles at the center of a neutron star, the equations must have some kind of a crack. We haven't found it in any of our searches so far, but we're sure it has to be there."

p. 158

"The result is that the universe must have started at a shockingly low-entropy--highly ordered--state when our own cosmic history began. This is a deeply uncomfortable idea for a lot of cosmologists. How did the entropy get set so low at the beginning? It's as if you walk into a room you're sure no one has ever been in before and you find rows and rows of dominoes lying on the floor, overlapping as if they've just toppled upon each other in sequence. How did they all get so carefully set up in the first place?"

p. 173

"We certainly have a lot to learn. Cosmology and particle physics are in an awkward position at the moment; both have, in some ways, been victims of their own success. In each field, we have a very precise and comprehensive description of the world that works extremely well in the sense that nothing has been found to contradict it. The downside is that we have no idea why it works."

p. 179

"In the meantime, we'll continue on, making new paths through the woods to see what we might find hiding there. Someday, deep in the unknown wilderness of the distant future, the Sun will expand, the Earth will die, and the cosmos itself will come to an end. In the meantime, we have the entire universe to explore, pushing our creativity to its limits to find new ways of knowing our cosmic home. We can learn and create extraordinary things, and we can share them with each other. And as long as we are thinking creatures, we will never stop asking: "What comes next?""

p. 203