Chapter 13 Chapter Eleven Master Mark's Quarks

In 1911, a British scientist named CTR Wilson often climbed to the top of Ben Nevis to study the structure of clouds.This mountain is located in Scotland and is known for its humidity.It suddenly occurred to him that there must be a simpler way.Back at the Cavendish Laboratory at the University of Cambridge, he built an artificial cloud chamber—a simple device in which he cooled and humidified the air, creating a plausible cloud in the laboratory's existing conditions. Cloud model. The device worked well, and had an unexpected benefit.When Wilson accelerated an alpha particle through a cloud chamber to create an artificial cloud, it left a distinct trail -- much like the condensation trail of a passing airplane.He had just invented a particle detector that provided convincing evidence that subatomic particles do exist.

Finally, two other scientists at the Cavendish Laboratory invented more powerful proton beam devices, and Ernest Lawrence built the famous cyclotron, or atom smasher, at the University of California, Berkeley. Devices have been called that for a long time.All of these new inventions operate on much the same principle, past and present, namely, to accelerate a proton or other charged particle along an orbit (sometimes circular, sometimes linear) to extremely fast speeds, and then slam Crash into another particle and see what gets blown away.So, it's called an atom smasher.It's not strictly a science, but it generally works.

As physicists built ever larger and more ambitious machines, they began or extrapolated a seemingly endless series of particles or families of particles: pions, muons, hyperons, mesons, kaons, Higgs Bosons, intermediate vector bosons, baryons, tachyons.Even physicists are starting to feel uncomfortable. "Young man," Enrico Fermi replied when a student asked him the name of a certain particle, "if I could remember the names of these particles, I would be a botanist." Today, accelerators have names that sound a bit like Flash Gordon's weapons of war: the Super Proton Synchrotron, the Large Electron Positron Collider, the Large Hadron Collider, and the Relativistic Heavy Ion Collider machine.The energy used is so great (some can only be operated at night, so that the residents of neighboring towns will not notice their lights dim when the device is fired), they can activate particles to such a state: an electron in the It can hit 47,000 laps along the 7 km long tunnel in less than 1 second.There are fears that scientists, in the heat of the moment, will inadvertently create a black hole, or even a so-called "strange quark".In theory, these particles could interact with other subatomic particles, creating a chain reaction that goes completely out of control.If you are alive and reading this book, that didn't happen.

Finding particles requires a certain amount of concentration.Particles are not only small, fast, and fleeting.Particles can appear and disappear in as little as 0.000 000 000 000 000 000 000 001 seconds (10-24 seconds).Even the most inert and unstable particles do not exist for more than 0.000 000 1 second (10-7 seconds). Some particles are barely caught.Every second, 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000’s of neutrinos that arrive on Earth, literally straight through the planet and everything on it things, including you and me, as if the earth didn't exist.In order to capture a few particles, scientists need to contain up to 57,000 cubic meters of heavy water (that is, water relatively rich in deuterium) in a basement (usually in an abandoned mine shaft), because this kind of place is not exposed to other types of radiation. interference.

Very occasionally, a passing neutrino will slam into an atomic nucleus in the water, generating a tiny bit of energy.Scientists are gradually understanding the fundamental nature of the universe by counting its bits and pieces. In 1998, Japanese observers reported that neutrinos do have mass, but not much -- about one ten-millionth that of an electron. Today, finding particles really costs money, and a lot of it.In modern physics, the size of the thing you are looking for is often interestingly inversely proportional to the size of the equipment you need.CERN is like a small city.It straddles the French and Swiss borders, employs 3,000 people, and occupies several square kilometers.CERN has a row of magnets heavier than the Eiffel Tower surrounded by an underground tunnel about 26 kilometers long.

According to James Trefil, it's easy to smash atoms, and you only need to turn on the fluorescent lamp every time.However, smashing the nucleus requires a lot of money and a lot of electricity.Turning particles into quarks—the particles that make them up—requires more electricity and more money: trillions of watts and the budget of a small Central American country.A new Large Hadron Collider at CERN, due to start operating in 2005, will generate 14 trillion watts of power and cost more than $1.5 billion to build.However, these two figures are nothing compared to the energy that the super superconducting collider could have produced and the construction costs required. In the 1980s, construction began on a supersuperconducting collider near Texas, which itself had a supercollider with the U.S. Capitol. Unfortunately, it will never be built now.The collider's purpose: to allow scientists to reconstruct as closely as possible the conditions of the universe's first ten-trillionth of a second, in order to explore "the ultimate nature of matter," as the saying goes.The plan involves flinging the particles down an 84-kilometre tunnel, yielding a truly mind-boggling 99 trillion watts of energy.It was a grand plan, but it cost $8 billion to build (eventually increased to $10 billion) and hundreds of millions more to run each year.

This is perhaps the best example of pouring money down a hole in history.The U.S. Congress spent $2.2 billion and then canceled the project after a 22-kilometer tunnel was completed.Now Texans can take pride in owning one of the most expensive burrows in the universe."It's really a big empty lot surrounded by a string of disappointed little towns," my friend Jeff Keen, author of "Fortress of Valor," told me. After the supercollider came to naught, particle physicists lowered their horizons a bit.But the cost of even a modest project can be pretty staggering when compared to, heck, almost any project.A proposed neutrino observatory at Homestake Mine, an abandoned mine in Ryder, South Dakota, would cost $500 million, not counting annual running costs.And, $281 million in "general remodeling costs."Meanwhile, a particle accelerator in Fermilab, Illinois, costs $260 million just to renew materials.

In conclusion, particle physics is an expensive business—and a hugely rewarding one.Today, the number of particles is well over 150, with another 100 or so suspected to exist.But unfortunately, in the words of Richard Feynman: "It is very difficult to know how all these particles are related, what nature wants them to do, and how they are related to each other." Every time we open a box, we always find There is also a closed box inside.Some believe that there are tachyons, which travel faster than the speed of light.Some yearn to find gravitons - the roots of gravity.It is hard to say how far we have gone to the bottom of the matter.Carl Sagan said in a book that if you drill into the depths of an electron, you will find that it is a universe in itself, which reminds you of those science fiction stories in the 1950s. "Inside, a large number of other particles, much smaller, make up the local equivalent of galaxies and smaller structures, which are themselves universes of the next level, and so on forever -- a gradual inward process, universes within universes , never ending--up is the same."

For most of us, this is an unimaginable world.Today, even with a beginner's guide to particle physics, you have to overcome language barriers such as: "A charged pion and an anti-pion decay into a muon plus an antineutrino and a muon, respectively. Anti-muons plus neutrinos have an average lifespan of 2.603×10-8 seconds; neutral π mesons decay into 2 photons, with an average lifespan of about 0.8×10-16 seconds; muons and anti-muons decay separately into..." and so on -- and, again, this quote is from a book written for a general audience by the (usually) shallow writer Stephen Weinberg.

In the 1960s, Caltech physicist Murray Gell-Mann tried to simplify things a little bit, inventing a new classification of particles that, in Stephen Weinberg's words, actually "to some extent Bringing the multitude of hadrons back into plain view"--hadron is a collective term used by physicists to refer to protons, neutrons, and other particles that are governed by the strong nuclear force.Gell-Mann's theory suggests that all hadrons are made of smaller, even more fundamental particles.His colleague Richard Feynman wanted to call these new elementary particles morons, as Dolly had done, but was rejected.They ended up being called quarks.

Gell-Mann took the name from a line in the novel Finnegan's Wake: "Three quarks to Master Mark!" rhyme, though it was almost evident that the latter pronunciation was in Joyce's mind. 1) This fundamental simplicity of quark didn't last long.As people learn more about quarks, a finer classification is needed.Although quarks are too small to have color, taste, or any other identifiable chemical property, they are grouped into six categories—up, down, odd, charmed, top, and bottom, which physicists strangely refer to collectively as For their "taste"; they are further divided into three colors: red, green and blue. (It is suspected that these names were originally used in California during the psychedelic era. This is not entirely a coincidence.) Finally, there came the so-called Standard Model.For the subatomic world, it is actually a component box.The composition of the standard model is: 6 kinds of quarks, 6 kinds of leptons, 5 kinds of known bosons and 1 hypothetical boson (that is, the Higgs boson, named after Scottish scientist Peter Higgs) name), plus 3 of the 4 physical forces: the strong nuclear force, weak nuclear force, and electromagnetism. What this arrangement actually means is that there are quarks in the building blocks of matter; quarks are held together by particles called gluons; and together, quarks and gluons form the stuff of atomic nuclei, namely protons and neutrons.Leptons are the source of electrons and neutrinos.Quarks and leptons are collectively called fermions.Bosons (named after Indian physicist SN Bose) are force-generating and carrying particles, including photons and gluons.The Higgs boson may or may not exist; it was all invented to give particles mass. You can see that this model is really a bit clumsy, but it is the simplest model that can be used to explain the whole situation of the particle world.Most particle physicists feel, as Leon Lederman put it in a 1985 TV show, that the Standard Model is not very elegant, not very concise. "It's too complex, with too many parameters that are too arbitrary," Lederman said. "We don't really understand why the Creator would have to turn 20 doorknobs and set 20 parameters in order to create the universe we all know." In fact , the task of physics is to explore ultimate simplicity, and everything so far has been a mess of beauty—or as Lederman puts it: "We feel deeply that the picture is not beautiful. " The Standard Model is clumsy and incomplete.For one thing, it doesn't talk about gravity at all.Search the entire Standard Model and you can't find any explanation why a hat sitting on a table doesn't fly up to the ceiling.To give a particle mass, you have to introduce the hypothetical Higgs boson, whether it really exists is up to 21st century physics to resolve.As Feynman put it heartfeltly: "We are thus in a dilemma about the theory, not knowing whether it is right or wrong, but we do know that it is somewhat wrong, or at least incomplete. " Physicists tried to tie it all together and came up with a so-called superstring theory.This theory posits that what we previously thought of as particles, quarks and leptons, are actually "strings" -- vibrating energy strings that wobble in 11 dimensions, including the three we know, plus time , and 7 other dimensions that, heck, we don't know yet.The strings are so tiny -- so small that they can be seen as point particles. By introducing extra dimensions, superstring theory allows scientists to bring the laws of quantum and gravity together in a relatively harmonious way, but it also means that any explanation scientists give to the theory will sound unsettling. It's like a stranger on a park bench telling you an idea, and you walk away slowly after hearing it.For example, physicist Michio Kaku explained the structure of the universe from the perspective of superstring theory: a hybrid string consists of a closed string, which has two modes of vibration, clockwise and counterclockwise Direction should be treated differently.Clockwise vibrations exist in a 10-dimensional space.The anti-clockwise vibration exists in a 26-dimensional space, 16 of which have been compacted. (We know that in Kaluza's original 5-dimensional space, the 5th dimension is rolled into a circle and has been compacted.) And so on, about 350 pages. String theory went one step further and gave rise to what is known as M-theory.This theory incorporates the so-called "membrane" into the soul of the physical world.Speaking of which, I'm afraid we've reached the stop on the Knowledge Highway, and it's time for most of you to get off.Here is a quote from The New York Times explaining this theory to the general reader in as simple a language as possible: In the distant distant past, the igneous process began with a pair of flat, empty membranes; they were parallel to each other in a curled 5-dimensional space... The two membranes formed the 5th-dimensional wall, It is likely that in the more distant past, as a quantum fluctuation, it was born out of nothing, and then drifted away. Can't argue with it, can't understand it.By the way, "pyrogenesis" is derived from the Greek word meaning "to burn". Problems in physics have now reached such heights that, as Paul Davies put it in Nature, "it's almost impossible for a non-physicist to tell if you're a reasonable oddball or a total lunatic" .Interestingly, in the autumn of 2002, this issue reached a critical moment.Two French physicists—twin brothers Igor and Grishka Bogdanov—proposed a theory of extremely high densities, including "imagined time" and Concepts such as the "Cooper-Schwinger-Martin condition" aim to describe nothing, the universe before the big bang - a period of time that has been considered unknowable (since it occurred before the birth of physical phenomena and their properties ). Bogdanov's theory sparked debate among physicists almost immediately: Is it nonsense, an achievement of genius, or a hoax? "From a scientific point of view, it's obvious that it's more or less utter nonsense," Columbia University physicist Peter Voight told The New York Times. What a difference." Karl Popper was called by Stephen Weinberg "the grandmaster of modern philosophers of science".At one point, he suggests that there is likely no one ultimate theory of physics—every explanation requires further explanations, forming "a never-ending series of more and more fundamental principles."The opposite possibility is that this knowledge may be completely beyond our comprehension. "Happily, so far," Weinberg wrote in "Dreams of a Final Theory," "our intellectual resources do not seem to have been exhausted. " It is almost certain that more insights will emerge in this field; almost equally certain that these insights will be beyond the reach of most of us. While mid-20th-century physicists were bewilderingly observing the small world, astronomers were discovering, equally remarkably, an incomplete understanding of the larger universe. As mentioned last time, Edwin Hubble has confirmed that almost all the galaxies in our field of vision are moving away from us, and the speed of this regression is proportional to the distance: the farther the galaxies are, the faster they move. quick.Hubble discovered that this can be expressed by a simple equation: Ho=v/d (Ho is a constant, v is the speed at which the galaxy is flying away, and d is its distance from us). Since then, Ho has been called Hubble's constant, and the whole equation has been called Hubble's law.Using his own equations, Hubble calculated the age of the universe to be about 2 billion years old.That number is a bit of a stickler, because even by the late 1920s it had become increasingly apparent that many things in the universe—likely including the Earth itself—were older than it was.Perfecting this number is a constant concern of the cosmology community. Regarding the Hubble constant, the only perennial constant is that there are different opinions on its evaluation. In 1956, astronomers discovered that Cepheids are more variable than they thought; Cepheids fall into two categories, not one.So they recalculated and came up with a new age of the universe of about 7 billion to 20 billion years—not particularly precise, but at least quite old enough to finally include the formation of the Earth. In the years since, a protracted debate has erupted between Hubble's successor at the Mount Wilson Observatory, Alan Sandage, and the French-born University of Texas astronomer Gérard de Wakule.After several years of careful calculation, Sandage concluded that the value of the Hubble constant is 50, and the age of the universe is 20 billion years.Vaukule is also confident that the Hubble constant is 100.1, which means that the universe is only half the size and age that Sandage thinks—10 billion years. Things suddenly became more uncertain in 1994, when a team at the Carnegie Observatories in California, based on measurements from the Hubble Space Telescope, proposed that the universe was only 8 billion years old—an age that, they admit, was less than Some stars in the universe are even younger. In February 2003, a team from NASA and the Goddard Space Flight Center in Maryland, using a new type of satellite called the Wilkinson Microwave Anisotropy Probe, announced with confidence that the age of the universe It is 13.7 billion years, with an error of about 10 million years.Things are on hold, at least for a while. It is indeed difficult to draw final conclusions, since there is often a great deal of room for interpretation.Imagine that you are standing in a clearing at night and trying to determine the distance between two distant electric lights.Using relatively simple astronomical tools, you can easily determine that both bulbs are equally bright, and that one bulb is 50% farther away than the other.But what you can't be sure of is whether the closer light, say, the 58-watt bulb 37 meters away, or the 61-watt bulb 36.5 meters away.Additionally, you have to account for distortions caused by several sources: changes in the Earth's atmosphere, interstellar dust, light pollution from background stars, and many others.Consequently, your calculations are bound to be based on a series of nested assumptions, any one of which may be controversial.There's another problem: Telescopes have always been expensive to use, and historically, measuring redshifts has required long, prohibitively expensive telescopes.It may well take an entire night to get a single negative.As a result, astronomers have had (or willed) to draw conclusions from the meager evidence.In cosmology, as the journalist Jeffrey Carr puts it, we "build mountains of theory on molehills of evidence."Or as Martin Rees puts it: "Our present satisfaction (in our state of knowledge) may reflect scarcity of data rather than excellence of theory." By the way, this state of uncertainty applies to things that are nearer, as well as to the far edges of the universe.When astronomers say the galaxy M87 is 60 million light-years away, as Donald Goldsmith says, they're really saying it's somewhere between 40-90 million light-years away - not exactly the same code thing.Things in the big universe are naturally exaggerated.With this in mind, our current best estimate of the universe seems to be between 12 billion and 13.5 billion years old, but that's far from a consensus. An intriguing theory has recently been put forward that the universe is not as big as we thought it was at all; that some of the galaxies we see when we gaze into the distance may just be reflections, double images of reflected light. In fact, there's still a lot we don't know, even at a very basic level -- at least not about how the universe is made.When scientists calculate the amount of matter needed to hold things together, they always turn out to be far from enough.At least 90 percent, perhaps as much as 99 percent, of the universe appears to be made up of what Fritz Zwicky called "dark matter" -- the kind of stuff that is inherently invisible to us.It's a little unpleasant to think that we live in a universe that we can't even see for the most part, and that we can't do anything about it.At least two of the main suspect's names have attracted attention: They are said to be either "WIMP" ("Weakly Interacting Massive Particle," the invisible tiny matter left over from the Big Bang) or "MACHO" ("halo-like massive particle"). Massively compact objects" are really just another term for black holes, brown dwarfs, and other very dim stars). Particle physicists often agree to explain it as a particle, that is, WIMP; astrophysicists agree to explain it as a star, that is, MACHO. MACHO had the upper hand for a while, but simply couldn't find enough of it, so the wind turned back to WIMP -- the problem was that WIMP was never found.Since their interactions are weak, it is difficult to identify them (even assuming their existence).Cosmic rays cause too much interference.So scientists have to drill deep into the ground.One kilometer underground, the bombardment intensity of cosmic rays is only one millionth of that on the ground.But even adding all that up, as one reviewer put it: "The universe is two-thirds off the balance sheet." For now, I might as well call them "DUNNOS" (somewhere unknown non-reflective unmeasurable objects). There have been recent signs that the universe's galaxies are not only receding from us, but are doing so at an increasing rate.This runs counter to people's expectations.It appears that the universe is filled not only with dark matter, but also with dark energy.Scientists sometimes refer to this as vacuum energy or the fifth element.In any case, the universe seems to be expanding, and no one can tell why.There are theories that the empty space of space isn't actually empty -- particles of matter and antimatter are constantly being created and vanished -- but that they're pushing the universe outward at an ever-increasing rate.Incredibly, the solution to all this was Einstein's cosmological constant - which he introduced in passing in his general theory of relativity to refute the hypothesis that the universe was expanding, and which he called "the biggest blunder of my life". " that little math.It now appears that he was right after all. After all, we live in a universe whose age we don't quite know; we're surrounded by stars whose distances to us and from each other we don't quite know; matter; the universe operates according to laws of physics whose nature we don't really understand. In such a very uncertain tone, let's go back to Earth and consider what we do understand - although so far, if you hear that we don't fully understand it, you probably don't To be amazed again -- and what we did not understand for a long time and now understand.