Cav > Books: physics‎ (61)

"Before the Second World War, military conflicts were fought under orthodox conditions, usually termed “conventional warfare,” but several innovations had significantly changed combat, leading inextricably to the race for a nuclear weapon in the 1930s and 1940s. Conflicts had been fought by armies on horseback with guns of varying sophistication since the 16th century, but mechanized warfare and machine guns changed this calculus and set the stage for future combat by the end of World War I. Other sinister changes entered the fray during this conflict, such as chemical weapons like chlorine and mustard gas. The total warfare brought about by World War I and ensuing wars like the Spanish Civil War made the quest for the most powerful weapons somewhat necessary."

"...Clouds spared one city, while one couple’s vacation decades earlier saved another. The story of Kyoto and Kokura poses an immediate challenge to our convenient, simplified assumptions of cause and effect following a rational, ordered progression. We like to imagine that we can understand, predict, and control the world. We want a rational explanation to make sense of the chaos of life. The world isn’t supposed to be a place where hundreds of thousands of people live or die from decades-old nostalgia for one couple’s pleasant vacation, or because clouds flitted across the sky at just the right moment."

"...Whenever we revisit the dog-eared pages within our personal histories, we’ve all experienced Kokura’s luck (though, hopefully, on a less consequential scale).
When we consider the what-if moments, it’s obvious that arbitrary, tiny changes and seemingly random, happenstance events can divert our career paths, rearrange our relationships, and transform how we see the world. To explain how we came to be who we are, we recognize pivot points that so often were out of our control. But what we ignore are the invisible pivots, the moments that we will never realize were consequential, the near misses and near hits that are unknown to us because we have never seen, and will never see, our alternative possible lives. We can’t know what matters most because we can’t see how it might have been.
If hundreds of thousands of people could live or die based on one couple’s vacation choice decades earlier, which seemingly trivial choices or accidents could end up drastically changing the course of your life, even far into the future? Could being late to a meeting or missing an exit off the highway not just change your life, but alter the course of history? And if that happened, would you even realize it? Or would you remain blind to the radically different possible world you unknowingly left behind?"

"I am a (disillusioned) social scientist. Disillusioned because I’ve long had a nagging feeling that the world doesn’t work the way that we pretend it does. The more I grappled with the complexity of reality, the more I suspected that we have all been living a comforting lie, from the stories we tell about ourselves to the myths we use to explain history and social change. I began to wonder whether the history of humanity is just an endless, but futile, struggle to impose order, certainty, and rationality onto a world defined by disorder, chance, and chaos.
But I also began to flirt with an alluring thought: that we could find new meaning in that chaos, learning to celebrate a messy, uncertain reality, by accepting that we, and everything around us, are all just flukes, spit out by a universe that can’t be tamed..."

We will tackle six big questions:
1. Does everything happen for a reason, or does stuff… just happen?
2. Why do tiny changes sometimes produce huge impacts?
3. Why do we cling to a storybook version of reality even if it’s not true?
4. Can’t we just tame flukes with better data and more sophisticated probability models?
5. Where do flukes come from—and why do they blindside us?
6. Can we live better, happier lives if we embrace the chaos of our world?

"Who has been the most influential person of the twenty-firstbcentury so far? Some might say Xi Jinping, or Vladimir Putin, or Donald Trump. I disagree. My nomination would be an unnamed person. The COVID- 19 pandemic likely started with a single person, in a single event, in Wuhan, China.VIII The lives of literally billions of people were drastically changed, for years, by one virus infecting one individual. Never in human history have the daily lives of so many people been so drastically affected, for so long, by one small, contingent event. Welcome to the swarm..."

"...The Moon’s influence goes back to the sulfurous origins of this planet and everything that crawls, flaps, swims, or strains skyward on its surface. The Moon guides all of us from its vaulted position above us. But it’s not apart from us, not least because it is actually a part of Earth. It was sheared from Earth when the planet was still freshly baked. And its elliptical orbit does not technically circle Earth, at least not in the way you might think. Instead, Earth and the Moon orbit each other, pivoting around a combined center of gravity that guides them both and that shapes their shared history.
Today, the Moon directs migrations, reproductions, the movements of the leaves of plants, and possibly the very blood in your veins. The Moon conducts the symphony of life on Earth, from the people who wage war on one another to the coral polyps that built the reefs of Tarawa. It has guided evolution since the moment of life’s first stirrings, which occurred either inside deep ocean vents or in warm little pools at the water’s edge, both of which derive nutrients through the Moon’s tide.
The Moon makes Earth unique, certainly in our solar system and possibly in the broader cosmos. It made us who we are, in ways that scientists are just beginning to understand, from our physiology to our psychology. It taught us how to tell time, which we used to impose order on the world. The Moon inspired the human projects of religion, philosophy, science, and discovery."

"This book is the story of our journey with the Moon in three parts: how the Moon was made, how the Moon made us, and how we made the Moon in our image. This is not solely an astronomy book, and it is not an Apollo book, though astronomy and the Apollo missions are both inseparable from humanity’s journey with the Moon. This is a book about time, life on Earth, human civilization, our place in the universe, and how the Moon has made all of it possible. I hope this book changes your understanding of all these things. And I hope it changes the way you see the Moon, this partner world that has always been with you, and which I hope you notice anew the next time you go outside at night."

"This special issue of Scientific American summarizes what science has discovered about how time permeates and guides both our physical world and our inner selves. That knowledge should enrich the imagination and provide practical advantages to anyone hoping to beat the clock or at least to stay in step with it."

"...Uranium will always be with us. Once dug up, it can never be reburied.
In this rock we can see the best and the worst of mankind: the capacity for scientific progress and political genius; the capacity for nihilism, exploitation, and terror. We must find a way to make peace with it. Our continuing relationship with uranium, as well as our future as a civilization, will depend on our capacity to resist mirroring that grim and never-ceasing instability that lies within the most powerful tool the earth has to give."

"...But perhaps the best way to grasp the enormity of predicting 100 years into the future is to recall the world of 1900 and remember the lives our grandparents lived.
Journalist Mark Sullivan asks us to imagine someone reading a newspaper in the year 1900: In his newspapers of January 1, 1900, the American found no such word as radio, for that was yet twenty years in from coming; nor “movie,” for that too was still mainly of the future; nor chauffeur, for the automobile was only just emerging and had been called “horseless carriage ….” There was no such word as aviator …. Farmers had not heard of tractors, nor bankers of the Federal Reserve System. Merchants had not heard of chain-stores nor “selfservice”; nor seamen of oil-burning engines …. Ox-teams could still be seen on country roads …. Horses or mules for trucks were practically universal …. The blacksmith beneath the spreading chestnut-tree was a reality."

"As a consequence, we are better able to see the direction that science and technology will take in the coming century. There will always be totally unexpected, novel surprises that leave us speechless, but the foundation of modern physics, chemistry, and biology has largely been laid, and we do not expect any major revision of this basic knowledge, at least in the foreseeable future. As a result, the predictions we make in this book are the product not of wild speculation but are reasoned estimates of when the prototype technologies of today will finally reach maturity.
In conclusion, there are several reasons to believe that we can view the outlines of the world of 2100:
1. This book is based on interviews with more than 300 top scientists, those in the forefront of discovery.
2. Every scientific development mentioned in this book is consistent with the known laws of physics.
3. The four forces and the fundamental laws of nature are largely known; we do not expect any major new changes in these laws.
4. Prototypes of all technologies mentioned in this book already exist.
5. This book is written by an “insider” who has a firsthand look at the technologies that are on the cutting edge of research."

"So when, in early 2018, I started seriously researching a new book on dark matter, I half-jokingly told the astrophysicists and particle physicists I was interviewing that I expected a revolutionary development in the field any day now. Wouldn’t it be great if my book were the first to report on the longawaited solution to the riddle of dark matter? The first to lay out what this mysterious stuff, said to constitute the balance of the cosmos, actually is?
Unfortunately, it didn’t happen. So here’s the spoiler: when you reach the last page of this book, you still won’t know what most of the material universe is made of. But neither do scientists. Despite decades of speculation, searching, studies, and simulations, dark matter remains one of the biggest enigmas of modern science. Still, after reading this book, you will have learned a lot about the miraculous universe we live in, and about the ways in which astronomers and physicists have teased out its secrets..."

"You can’t put a galaxy on a scale, but there are other ways to estimate their mass. Just look at how strongly they tug on their neighbors. Our Milky Way galaxy is surrounded by dwarf galaxies. The dimensions—and relatively sharp edges—of these satellites are governed by the interplay between their own internal gravity and the Milky Way’s mass. Elsewhere, the dynamics of small groups of galaxies and of galaxy pairs, orbiting each other, provide information on galaxy masses. And wherever you look, you see the same thing: evidence for much more mass than you would expect on the basis of the amount of light you’re seeing. Or, in the language of astrophysicists, a very high mass-to-light ratio."

"As a quick recap, we’ve learned that galaxies can’t be stable, unless they’re embedded in giant, massive halos. Moreover, galaxies are much more massive than you would guess on the basis of their visible content. Rotational velocities do not decrease with increasing distance from the galaxy’s center but remain more or less constant—a sign that there is more matter in galaxies than is apparent through telescopes. The relative smoothness of the cosmic microwave background suggests that, in the moments after the big bang, weird particles must have already started to form a dark, massive scaffolding that would only later pull in the familiar baryonic matter. Finally, the big bang cannot have produced enough baryonic matter to explain the dynamical observations and the growth of cosmic structure, indicating that most of the gravitating mass in the universe must be in some unfamiliar, nonbaryonic form..."

"When you hold clear, focused thoughts about your purpose, accompanied by your passionate emotional engagement, you broadcast a stronger electromagnetic signal that pulls you toward a potential reality that matches what you want."

"If the extra push that propelled ‘Oumuamua was from the rocket effect, as it is for comets, then our interstellar object should have lost a tenth of its mass in order for it to be propelled as much as it was. This is not a negligible amount of outgassing that could easily have been missed by our telescopes. But deep observations of the space around ‘Oumuamua did not reveal any trace of water, carbon-based gases, or dust, ruling out the possibility that it was being pushed by cometary vapor or visible dust particles. Moreover, it did not change its spin rate as it should have if one-sided jets were pushing it sideways, as they often do in comets. Then, too, such a massive evaporation would have changed the tumbling period of ‘Oumuamua, a phenomenon that is seen in solar system comets. No such change in the spin rate was recorded.
Ultimately, all of these mysteries can be traced back to one: ‘Oumuamua’s deviation from its expected path. All hypotheses as to what ‘Oumuamua is have to account for that deviation, and that means explaining the force that acted on it while respecting the fact that if there was any cometary tail of gas and dust behind it, that tail was slight enough to go undetected by our equipment..."

"Let us pause here briefly to recap the evidence that emerged about ‘Oumuamua in the weeks immediately following its discovery. It was a small, oddly shaped, shiny object that deviated from an orbit shaped by the Sun’s gravity without showing any discernible cometary tail (caused by the outgassing of a comet’s ice turning to steam by friction and the warmth of the Sun) despite a deep search for it with the Spitzer Space Telescope and other detectors.
These are certainties, and they allow us to declare confidently that the first three of ‘Oumuamua’s identified anomalies—its unusual orbit without a tail, its extreme shape, and its luminosity—make it statistically different, by a large margin, from all other objects cataloged by humanity. To put this distinctiveness in statistical terms, we can conservatively state that based on its extra push and its lack of a cometary tail, ‘Oumuamua is a one-in-a-few hundred object. Based on its shape, it is, also
conservatively, a one-in-a-few-hundred object. And based on its reflectivity, it is (again, conservatively) at least a one in-ten object. When we multiply those three anomalous qualities, we can appreciate how much of an outlier ‘Oumuamua is. It is now a one-in-a-million object.
Those three traits—orbit, shape, and reflectivity—do not exhaust ‘Oumuamua’s weirdness, as we know. Alone, however, these three traits do clearly defy the understandable but naive expectation that our first interstellar visitor would resemble the rocky asteroids and icy comets that we know have passed through our solar system.
Yet even as these anomalies mounted, most scientists clung to the most familiar explanation: that ‘Oumuamua had to be a naturally occurring object, an asteroid or comet. Most scientists—but not all. Even our community, you see, has its anomalies.
With my work on the Starshot Initiative fresh in my mind, I, for one, was finding myself pulled toward a different hypothesis..."

"But solar radiation pressure isn’t very powerful. If it were indeed responsible, we calculated, then ‘Oumuamua had to be less than a millimeter thick and at least twenty meters wide. (The diameter depends on the object’s reflectivity, which is unknown. If ‘Oumuamua were a perfect reflector, bouncing back 100 percent of the sunlight that hit it, in this super-thin scenario it would be twenty meters across.)
There is nothing in nature with those dimensions, as far as we can tell, and no known natural process that can produce them. But of course, humanity has built something that fits the bill, and we’ve even launched it into space: a lightsail.
We arrived at this hypothesis through logic and evidence —in short, by sticking to the facts. But if we take the hypothesis seriously, it allows us to ponder new, incredible questions about how ‘Oumuamua appeared in our universe and where it came from. It even, as I will explain, gives us the opportunity to ask whether we might someday meet the creators of this mysterious visitor.
The lightsail hypothesis opens up a world of possibilities— unlike the comet hypothesis, which closes them off. The fact that scientific consensus strongly favors the more conservative and restrictive of these two possibilities says less about the evidence than it does about the practitioners and culture of science itself..."

"So I wrote them back a letter that said, “After reading the salary, I’ve decided that I must refuse. The reason I have to refuse a salary like that is I would be able to do what I’ve always wanted to do - get a wonderful mistress, put her up in an apartment, buy her nice things.. . With the salary you have offered, I could actually do that, and I know what would happen to me. I’d worry about her, what she’s doing; I’d get into arguments when I come home, and so on. All this bother would make me uncomfortable and unhappy. I wouldn’t be able to do physics well, and it would be a big mess! What I’ve always wanted to do would be bad for me, so I’ve decided that I can’t accept your offer.”

"In the South Seas there is a cargo cult of people. During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So they've arranged to imitate things like runways, to put fires along the sides of the runways, to make a wooden hut for a man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas—he's the controller—and they wait for the airplanes to land. They're doing everything right. The form is perfect. It looks exactly the way it looked before. But it doesn't work. No airplanes land. So I call these things cargo cult science, because they follow all the apparent precepts and forms of scientific investigation, but they're missing something essential, because the planes don't land..."