Chapter 3 Chapter 1 How to Build a Universe

They are all on the same plane.They're all turning in the same direction... You know, it's just flawless, it's uncanny, it's almost magical. --A description of the solar system by astronomer Geoffrey Massey No matter how hard you try, you can never imagine how tiny the proton is and how little space it occupies.It is simply too small. Protons are tiny building blocks of atoms, and atoms themselves are of course tiny.How small is a proton?A drop of ink the size of the dot on the letter "i" can hold about 500 billion protons, or more precisely, more than the number of seconds that make up 15,000 years.So protons are extremely tiny, to say the least.

Now, imagine if you could (of course you can't) shrink a proton down to a billionth of its normal size, into a tiny space, and make it look huge, and then you put about 30 Grams of matter fit into that tiny, tiny space.Great, you're ready to create a universe. I guess of course that you want to create an expanding universe.However, if you're willing to create an older, standard Big Bang universe, you'll need something else.In fact, you need to take everything that exists—every particle from now until the creation of the universe—and cram it into something so tiny that it’s not even a size.This is the so-called singularity.

In either case, get ready for a real blast.Naturally, you want to retreat to a safe place to observe this spectacle.Unfortunately, there is nowhere for you to retreat, because there is nowhere beyond the singularity.When the universe started expanding, it didn't expand outward, filling a larger space.The only space is the space it creates as it expands. It is natural, but wrong, to think of the singularity as a gestation point suspended in a black, boundless void.There is no space, no darkness.There are no four weeks around the singularity.There is no room for it to occupy, no place for it to be.We can't even ask how long it's been there -- has it just been born, like a good idea, or has it been there, silently waiting for the right moment.Time does not exist.It did not generate this from the past.

Thus, our universe was created from nothing. In an instant, a glorious moment came, the speed and scope of which could not be described in words, the singularity became as big as the sky and the earth, and had an unimaginable space.This energetic first second (1 second that many cosmologists will spend their lives breaking up into smaller and smaller fractions) gives rise to gravity and the other forces that govern physics.In less than 1 minute, the diameter of the universe has reached 1600 trillion kilometers, and it is still expanding rapidly.That's when there's a lot of heat, up to 10 million degrees Celsius, enough to start a nuclear reaction that results in the creation of lighter elements -- mostly hydrogen and helium, with a small amount of lithium (about 1 lithium in 10 million atoms) atom). After 3 minutes, 98% of the material that exists or will exist has been produced.We have a universe.It's a wonderful place, and it's beautiful.It all comes together in about the time it takes to make a sandwich.

The timing of this momentous moment is a matter of some debate.Cosmologists have debated for a long time whether the universe was formed 10 billion years ago, 20 billion years ago, or between 10 billion and 20 billion years ago.There seems to be growing agreement on a figure of around 13.7 billion years.But, as we shall see further on, such things are extremely difficult to calculate.In fact, we can only say that in the very distant past, at an undetermined moment, due to unknown reasons, the moment called t=0 in science came.So we set out on a journey. Of course, there are tons of things we don't know, and tons of things we don't know now, or thought we knew for a long time in the past.Even the big bang theory was proposed not so long ago.The concept has been popular since the 1920s, when it was first hypothesized by a Belgian priest-scholar named Georges Lemaitre.However, it was not until the mid-1960s that this theory became active in the cosmological community.At that time, two young radio astronomers stumbled upon an extraordinary phenomenon.

Their names were Arno Penzias and Robert Wilson. In 1965, at Bell Laboratories in Holmdel, New Jersey, USA, they wanted to use a large communication antenna, but they were constantly disturbed by a background noise-a continuous steam-like hissing sound, making the The experiment cannot proceed.The noise was non-stop and very unfocused.It comes from all directions in the sky, day and night, all year round.For a year, two young astronomers tried their best to track and eliminate this noise.They tested every electrical system.They reassembled the equipment, checked the wiring, inspected the wires, and dusted the sockets.They climbed into the parabolic dish and covered every seam, every rivet with duct tape.They took brooms and rags and climbed into the dish again, carefully sweeping away what they later called in a paper "white dielectric" and, more commonly, bird droppings.But their efforts were in vain.

They didn't know that just 50 kilometers away at Princeton University, a team of scientists led by Robert Dick was trying to find what the two astronomers wanted to get rid of.Researchers at Princeton University are working on a hypothesis proposed by George Gamow, a Soviet-born astrophysicist in the 1940s: If you look deep into space, you'll find some kind of cosmic background radiation left over from the Big Bang .Gamow estimated that after passing through the vast universe, that radiation would reach the earth in the form of microwaves.In a recently published paper, he even suggested that an instrument could be used for this purpose, which was Holmdel's Bell Antenna.Unfortunately, neither Penzias and Wilson, nor any of the experts in the Princeton group, had seen Gamow's paper.

The noise Penzias and Wilson heard was exactly what Gamow had assumed.They have found the edge of the universe, at least the visible part of the universe 15 billion light-years away.They were "watching" the first protons -- the oldest light in the universe -- and sure enough, time and distance had transformed them into microwaves, as Gamow expected.Alan Guth offers an analogy in his book The Expanding Universe that helps put this discovery in place.If you compare looking into the depths of the universe to looking down from the 100th floor of the Empire State Building in New York (assuming that the 100th floor represents the present, and the street represents the moment of the big bang), then when Penzias and Wilson discovered that phenomenon, The farthest galaxies ever discovered are at about the 60th layer, and the most distant things -- quasars -- are at about the 20th layer.Penzias and Wilson's discovery pushed our knowledge of the visible part of the universe about 1 centimeter across the hall floor.

Still unable to find the cause of the noise, Penzias and Wilson called Dick at Princeton to describe their problem and hope he could come up with an explanation.Dick realized at once what the two young men had discovered. "Oh, man, they beat us." He said to his colleagues while hanging up the phone. Shortly thereafter, the Astrophysical Journal published two articles: one by Penzias and Wilson describing the experience of hearing the hiss, and one by Dick's group explaining its nature.Although Penzias and Wilson were not looking for cosmic background radiation, did not know what it was when they found it, and did not publish any papers describing or explaining its properties, they were awarded the 1978 Nobel Prize in Physics.The Princeton researchers had nothing but sympathy.According to Dennis Overby in "A Lonely Heart in the Universe," neither Penzias nor Wilson knew the significance of their discovery until they saw a report in the New York Times.

By the way, interference from cosmic background radiation has been experienced by all of us.Tune your TV to any channel with no reception, and about 1 percent of the jagged static you see is caused by this ancient Big Bang remnant.Remember, the next time you complain about not receiving a picture, you can always watch the birth of the universe. Although everyone calls it the Big Bang, many books remind us not to regard it as an explosion in the ordinary sense, but a sudden explosion with an extremely large scope and scale.So, what is its cause? It has been suggested that the singularity may be a remnant of an earlier universe that was destroyed -- ours is just one of a series of universes.These universes go on and on, expanding and destroying like the air pockets of an oxygen machine.Some have attributed the Big Bang to a so-called "pseudo-vacuum", or a "scalar field", or "vacuum energy"—something, anyway, that introduced a certain amount of instability into what was then exist.Getting some kind of existence out of non-existence might seem improbable, but it turns out that it is clearly possible to have a universe where there was nothing in the past.It may be the case that our universe is just part of many larger universes of varying sizes, with the Big Bang happening all over the place.Or perhaps, before that big bang, time and space had some entirely different form - forms so unfamiliar to us that we cannot imagine them - that the big bang represented some transitional stage in which the universe evolved from a The form of understanding transitions to a form that we can almost comprehend. "It's very similar to the question of religion," Dr. Andre Lind, a cosmologist at Stanford University, told a New York Times reporter in 2001.

The Big Bang Theory is not about the explosion itself, but what happened after the explosion.Note that it was shortly after the explosion.Scientists did a lot of calculations and looked carefully at what was going on in particle accelerators, and then thought they could look back 10-43 seconds after the explosion, when the universe was still so small that it could only be seen with a microscope.We don't have to dazzle ourselves with every extraordinary number that comes our way, but sometimes we might as well make sense of one, just so as not to forget how elusive and surprising it is.Thus, 10-43 seconds is 0.000 000 000 000 000 000 000 000 000 000 000 000 000 000 1 second, or a trillionth of a billionth of a billionth of a second.Much of what we know, or think we know, about the early universe is due to the theory of inflation, first proposed in 1979 by a young particle physicist.His name was Alan Guth, and he was working at Stanford and now at MIT.He was 32 years old at the time, and by his own admission had never achieved much before.If he hadn't happened to attend that lecture on the Big Bang, he probably would never have come up with that great theory.The lecturer was given by none other than Robert Dick.The lectures developed Guth's interest in cosmology, especially in the formation of the universe. Finally, he came up with the theory of inflation.The theory holds that in the instant after the explosion, the universe suddenly underwent a dramatic expansion.It's constantly expanding -- literally fleeing with itself, doubling in size every 10-34 seconds.The entire process may have lasted no more than 10-30 seconds -- that's a million-trillion-trillion-trillionth of a second -- but the universe went from being something you could hold in your hand to being at least a billion-trillion-trillion-trillion times bigger. thing.Inflation theory explains the pulsations and rotations that make our universe possible.Without this pulsation and rotation, there would be no clumps of matter, and therefore no stars, but only floating gas and eternal darkness. According to Guth's theory, gravity is created in a hundred million million million million million million million million million million million million millionths of a second.After another very brief moment, there was electromagnetism and the strong and weak nuclear forces - the stuff of physics.Afterwards, a large number of elementary particles—materials of materials—appeared soon.From nothing, there are suddenly huge numbers of photons, protons, electrons, neutrons and many other things -- as many as 1079-1089 of each, according to the standard big bang theory. Such a large number is of course incomprehensible.It is enough to know that, for a moment, we have a huge universe -- so large, according to the theory, that it has a diameter of at least 1 000 billion light-years, but could be any size up to infinity - perfectly arranged to allow for the creation of stars, galaxies and other complex systems. From our point of view, it's incredible how perfect this turned out for us.If only the universe had been shaped a little differently -- if only gravity had been slightly stronger or weaker, if expansion had been slightly slower or faster -- then perhaps there would never have been stable elements to make you and me, and the ground beneath our feet .Had gravity been a little stronger, the universe itself would have collapsed like an ill-constructed tent, not having just the right values ​​to give itself the necessary size, density, and composition.However, if it is weaker, nothing will come together.The universe will always be monotonous, scattered, and empty. This is one of the reasons why some experts think there may be many other Big Bangs, maybe trillions of Big Bangs, distributed over an infinite eternity; we exist in this particular universe because of this The universe is suitable for our existence.As Edward P. Tryon of Columbia University puts it: "To answer why it came into being, my humble opinion is that our universe is just one of those things that come into being from time to time." To this, Guth added: " While creating a universe is unlikely, Tryon stresses that no one has counted the number of failures." Astronomer Royal Martin Rees believes that there are many universes, possibly an infinite number, each with different properties and combinations, and we just live in a universe whose combination is just right for us.He draws an analogy with the example of a large clothing store: "If there's a wide variety of clothing, it's not hard to find a dress that fits you well. If there are many universes, each governed by a different set of data, then the There will be a universe with a specific set of data suitable for life. We happen to be in such a universe." According to Rees, our universe is governed by six numbers, and if any one value changed even slightly, things couldn't be the way they are now.For example, the existence of the present universe requires hydrogen to be converted into helium in an accurate and relatively stable manner—specifically, in a manner that converts seven thousandths of its mass into energy.Had that value been slightly lower—say, from seven to six thousandths—then no transformation would have been possible: the universe would consist only of hydrogen.Had that been a little higher—as high as 8 parts per thousand—the bonding would have happened without interruption, and the hydrogen would have been used up long ago.In either case, if this data were to change even slightly, the universe as we know it and need it would not exist. I would say that so far, everything has hit the spot.In the long run, gravity might become a little stronger; one day it might stop the universe from expanding, allowing it to collapse itself into another singularity, and the whole process could start all over again.On the other hand, gravity might become too weak, in which case the universe would expand forever until everything is so far away from each other that no substantial interaction is possible, and the universe becomes a very empty, lifeless space. place.A third possibility is that gravity is just right -- what cosmology calls "critical density" -- and it keeps the universe in just the right range to keep things going forever.Cosmologists sometimes frivolously refer to this as the "Goldilocks effect"—everything is just right. (It should be noted that these three possible universes are called closed universe, open universe and flat universe.) Sooner or later, everyone will think of a problem, that is, suppose you come to the edge of the universe and stick your head out of the curtain , what happens then?Where would your head be (if it were no longer in the universe)?What do you see on the other side?The answer is disappointing: you'll never reach the edge of the universe.Not because it takes a long time to get there--though yes, it does take a long time--but because, if you keep going out in a straight line and keep going out, you'll never get there the edge of the universe.Quite the contrary, you'll be back where you started (to the point where you're likely to get discouraged and give up on the effort).The reason for this is that, according to Einstein's theory of relativity (which we'll get to in a moment), the universe is curved.As for how to bend, we can't imagine it.For now, just know that we're not floating in a big, expanding bubble, and that's enough.Rather, space is curved, just to make it both infinite and finite.Fittingly, it can't even be said that space is expanding, because, as Nobel Prize-winning physicist Steven Weinberg pointed out: "The solar system and the galaxies are not expanding, and neither is space itself." Instead, the galaxies are moving away from each other rapidly.This is a challenge to intuition.Biologist JBS Haldane famously said, "The universe is not only weirder than we thought, but weirder than we could possibly imagine." To explain the curvature of space, people often come up with an analogy in which they try to imagine that a being from a flat universe who has never seen a sphere comes to Earth.No matter how far he traveled on the surface of this planet, he could never reach the end.He will likely end up back where he started.Of course he would be confused and couldn't tell what was going on.Heck, our situation in space is exactly the same as that gentleman's.We are just more confused. Just as you can't find the edge of the universe, you can't stand at the center of the universe and say, "This is where the universe began. This is the center of everything." We are all in the center of everything.In fact, we are less sure about it.We cannot prove it mathematically.Scientists just speculate that we are indeed in the center of the universe -- think about what that would mean -- but the phenomenon is the same for all observers, everywhere.We're really not sure, though. As far as we know, the universe has only grown so far that light has traveled billions of years since its formation.The diameter of the visible universe—the universe we know and talk about—is 150,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 000) km.But, according to most theories, the entire universe—sometimes called the superuniverse—is much wider.According to Rees, the number of light-years to the edge of this larger, invisible universe is expressed not "in 10 zeros, nor in 100 zeros, but in millions of zeros."In short, the existing space is bigger than you imagined, and you don't have to imagine that there is room outside the space. For a long time, the big bang theory has had a huge hole that many people have puzzled over -- namely, that it simply doesn't explain how we got into this world.While 98% of all matter in existence was created by the Big Bang, that matter consists entirely of light gases: the helium, hydrogen, and lithium we mentioned above.Not a single particle of the heavy matter that is so vital to our existence—carbon, nitrogen, oxygen, and everything else—was a gas created during the creation of the universe.But -- and here's the trick -- to create these heavy elements, you have to have the kind of heat and energy released by the Big Bang.However, the Big Bang happened only once, and that Big Bang produced no heavy elements.So where do they come from?Interestingly, the answer to this question was found by a cosmologist who had so little contempt for the Big Bang theory that he coined the term Big Bang as a sarcasm. We'll get to him shortly.However, before discussing how we got here, it may be worth taking a few minutes to consider what exactly "here" is.