Chapter 5 Chapter 3 The Universe of Reverend Evans

Pastor Robert Evans is a quiet, cheerful man who lives in the Blue Mountains of Australia, about 80 kilometers west of Sydney.When the sky is clear and the moon is not too bright, he takes a big, clumsy telescope out to his back porch and does something extraordinary.He looks into the distant past, looking for dying stars. Looking at the past is of course the easy part.Glance at the night sky and you see history, a lot of history -- you see the stars not as they are now, but as they were when their light came out.As far as we know, our faithful companion, the North Star, actually probably went out last January, or 1854, or anytime since the beginning of the fourteenth century, because the message has not been able to get here yet.The best we can say - and we can always say - is that it still shines today, 680 years ago.Stars are dying.What Robert Evans did better than anyone else was to spot the moment when the celestial bodies bid farewell.

By day, Evans is an affable, near-retired pastor of the Unity Church of Australia, working odd jobs and researching the history of religious movements in the 19th century.At night, he quietly becomes a god of the sky, hunting for supernovas. When a massive star -- a star larger than our own sun -- collapses, it then explodes spectacularly, unleashing in an instant the energy of 100 billion suns, momentarily larger than all stars in our own galaxy. The combined brightness of the stars is even brighter.Thus, a supernova was born. "It's like a trillion hydrogen bombs going off all of a sudden," Evans said.He also said that if a supernova had happened only 500 light-years away, we would have been screwed—"totally blown the pot," he says cheerfully.However, the universe is vast, and supernovae are usually far, far away from us and will not cause us harm.In fact, most are so unimaginably far away that their light reaches us but a faint flicker.For a month or so, they are visible.The only difference between them and other stars in the sky is that they occupy a little space that was previously empty.It was this very unusual, very occasional flash of light that Evans was looking for in the starry sky at night.

To understand what a feat this is, imagine a standard dining table covered with a black tablecloth and sprinkled with a handful of salt.We compare grains of salt to a galaxy.Now, let's imagine adding 1,500 more of these tables - enough to form a straight line 3 kilometers long - each with a random handful of salt sprinkled on it.Now, take any table with a grain of salt and let Robert Evans walk in the middle.He saw the grain of salt at a glance.That grain of salt is a supernova. Evans was such a brilliant genius that Oliver Sachs, in An Anthropologist on Mars, devotes a paragraph to Evans in his chapter on solitary academics - but he adds right away: "Never meant he was withdrawn." Evans, who had never met Sachs before, laughed at the suggestion that he was withdrawn or a scholar, but he couldn't quite explain why he was. kind of genius.

Evans' home is in a bungalow on the edge of Hazelbrook Village. The environment is quiet and the scenery is picturesque. Sydney ends here, and then there is the boundless Australian bush.Once, I visited him and his wife, Elaine. "I just happen to have a knack for remembering star fields," he said to me, sheepishly. "I'm not particularly good at anything else," he continued. "I don't even remember names very well. ." "Can't remember where I put things," Elaine yelled from the kitchen. He nodded bluntly again, grinned, and asked if I'd like to take a look at his binoculars.I originally thought that Evans had a nice observatory in the backyard—a small Mount Wilson or Palomar Observatory with a sliding domed roof and a mechanical chair that moved easily.In fact, instead of taking me outside, he led me into an overcrowded storeroom not far from the kitchen, full of books and papers.His telescope -- a white cylinder the size and shape of a domestic hot water tank -- rests on a plywood stand that he made himself that turns.When it was time to make observations, he moved them to the balcony not far from the kitchen twice.The lower slopes are covered with eucalyptus trees, and all that's visible is a letterbox-sized patch of sky between the eaves and treetops, but he says that's more than enough for his observations.It's there, when the sky is clear and the moon isn't too bright, that he looks for supernovae.

The name supernova was coined in the 1930s by an extremely eccentric astrophysicist named Fritz Zwicky.Born in Bulgaria and raised in Switzerland, he came to Caltech in the 1920s and soon became known for his gruff nature and brilliant brilliance.He didn't seem particularly bright, and many of his colleagues thought he was nothing more than an "annoying clown".He was a fitness freak, and would often throw himself on the floor of a Caltech dining room or other public space doing one-armed push-ups, showing off his masculinity to anyone who doubted it.He was aggressive, eventually becoming so menacing that even his closest collaborator, the mild-mannered Walter Budd, was reluctant to be alone with him.Zwicky also accused Bader of being a Nazi because he was German.Actually, he is not.Bud works at the Mount Wilson Observatory on the mountain.Zwicky threatened more than once that if he ran into him on the Caltech campus, he would kill Bud.

Zwicky, however, was brilliant and possessed keen insight. In the early 1930s, he turned his attention to a problem that had long troubled astronomers: the occasional and unexplained blips of light in the sky—new stars.Incredibly, he wondered whether the heart of the matter lay in the neutron—the new, and therefore novel and trendy, subatomic particle just discovered by James Chadwick in England.It occurred to him that if a star were to collapse to the density of an atomic core, it would form an extremely solid nucleus.The atoms had actually been crushed together, and their electrons had to turn into nucleons, forming neutrons.Thus a neutron star is formed.Imagine squeezing a million heavy shells to the size of a single pellet -- heck, that's not even close.A neutron star core is so dense that a spoonful of matter inside would weigh 90 billion kilograms.Just a spoon!However, it is not only that.Zwicky realized that the collapse of such a star would release a tremendous amount of energy—enough to produce the largest explosion in the universe.He called the resulting explosion a supernova.They will be - indeed are - the biggest events in the creation of the universe.

On January 15, 1934, a short abstract of a paper appeared in the journal Physical Review.The paper had been presented by Zwicky and Bard at Stanford the previous month.Although the abstract is extremely short—just 24 lines—it contains a wealth of new scientific knowledge: it mentions supernovae and neutron stars for the first time; it convincingly explains how they form; class; as a conclusion, it links supernova explosions to the creation of a mysterious new phenomenon called cosmic rays.Cosmic rays travel through the universe in large numbers and are only recently discovered.These ideas were revolutionary to say the least.The existence of neutron stars was not confirmed for another 34 years.The idea of ​​cosmic rays, while considered plausible, has not been proven.All told, the abstract is "one of the most prescient documents in the history of physics and astronomy," in the words of Caltech astrophysicist Kip S. Thorne.

Interestingly, Zwicky has little idea of ​​why this is happening.According to Thorne: "He didn't know much about the laws of physics, so he couldn't prove his ideas. Zwicky's brilliance was used to think about big problems, and collecting data was someone else's business—mainly Bud. " Zwicky was also the first to realize that the visible matter in the universe is far from enough to hold the universe together, and that there must be some other gravitational influence—what we now call dark matter.What he didn't notice was that the neutron star collapsed so tightly and so densely that not even light could escape its enormous gravitational pull.This forms a black hole.Unfortunately, most of his colleagues looked down on him, so his ideas received little attention. Five years later, when the great Robert Oppenheimer turned his attention to neutron stars in a landmark paper, he did not once mention Zwicky's achievement, although Zwicky had been working on it for many years. For the same problem, and in the office down the hall.For almost 40 years, Zwicky's theories about dark matter received no serious attention.We can only assume that he did a lot of push-ups during this time.

It is astonishing that when we poke our heads skyward, we can only see a tiny fraction of the universe.From Earth, only about 6,000 stars are visible to the naked eye, and only about 2,000 from one angle.If we use a telescope, the number of stars we can see from one place increases to about 5,000; if we use a small 5 cm telescope, this number jumps to 300,000.With a 40-centimeter telescope like the one Evans uses, we can count not only stars but galaxies as well.Evans estimated that from his balcony he could see 50,000 to 100,000 galaxies, each consisting of tens of billions of stars.That's a significant number, of course, but even with so many to see, supernovae are extremely rare.A star can burn for billions of years, but it dies all at once.Only a handful of dying stars explode, and most die silently, like a bonfire at dawn.In a typical galaxy consisting of hundreds of billions of stars, a supernova occurs on average every two to three hundred years.Finding a supernova, then, is a bit like standing on the observation deck of the Empire State Building in New York, with a telescope scanning around Manhattan outside the window, hoping to find -- say -- someone lighting the candles on their 21st birthday cake.

So if a hopeful, soft-spoken priest came to contact and asked if they had any usable maps of star fields to look for supernovae, the astronomy community would think he was out of his mind.At the time, Evans had only a 5-centimeter telescope—good enough for amateur stargazing, but far from enough for serious cosmic research—and he proposed to find rarer objects in the universe. The phenomenon.Before Evans began observing in 1980, fewer than 60 supernovae had been discovered in the entire history of astronomy. (By the time I visited him in August 2001, he had recorded his 34th visual discovery; 3 months later, his 35th; and in early 2003, his 36th.) However, Evan S has certain advantages.Most observers, like most of the population, are in the Northern Hemisphere, so being in the Southern Hemisphere he has a large piece of the sky largely to himself, especially at first.He also possesses speed and superhuman memory.Large astronomical telescopes are cumbersome things, and it takes a lot of manipulative time to move them into place.Evans can turn the small 5-centimeter telescope around like a tail shooter in close air combat, and can aim at any specific point in the sky in a few seconds.Therefore, he may be able to observe 400 galaxies in one night, while a large professional astronomical telescope can observe 50 or 60 galaxies is very good.

The search for supernovae has mostly turned up nothing.From 1980 to 1996, he made an average of two discoveries a year--that would take hundreds of nights to observe and observe, which is really not worthwhile.Once he had 3 discoveries in 15 days, but another time he didn't find 1 in 3 years. "There's actually some value in finding nothing," he said. "It helps cosmologists figure out how fast galaxies are evolving. In regions where there's so little to discover, no signs are signs." On a table next to the telescope are stacks of photographs and documents related to his research.Now, he's showing me some of them.If you have read popular publications on astronomy, you will know that most of them are brightly colored photographs of distant nebulae and the like--colorful clouds formed by skylight, which are gorgeous and magnificent.The images Evans captured simply don't compare.They're just blurry black-and-white photos with tiny bright spots with halos.He showed me a picture that depicted a large group of stars with a little flare that I had to get very close to see clearly.Evans told me that this is a star in the constellation Forna, known in astronomy as NGC 1365. (NGC stands for "New General Catalogue," which records this material. It used to be a bulky book on someone's desk in Dublin; today, it goes without saying, it's a database.) Over 60 million years, the star's The light emitted by the magnificent death traveled across space continuously, and finally reached the earth in the form of a twilight in one night in August 2001.Of course it was Robert Evans on a eucalyptus-scented hillside who discovered it. "I think that's quite satisfying," Evans said, "thinking about that light that traveled through space for millions of years, and when it arrived on Earth, there happened to be someone watching it impartially." That sky, and seeing it as a result. It seemed pretty good to be able to witness such a momentous event." Supernovas do much more than give you a sense of wonder.There are several types of them (one was discovered by Evans), one of which is called Type Ia supernovae, which are of particular importance to astronomy because they always explode in the same way and have the same critical mass .As such, they can be used as "standard candles" -- a measure of the brightness (and thus relative distance) of other stars, and thus the expansion rate of the Universe. In 1987, Saul Perlmutter of the Lawrence Berkeley Laboratory in California began looking for a more systematic search method, in need of a larger number of supernovae than visual observations could provide.Using state-of-the-art computers and charge-coupled devices, Perlmutter devised an ingenious system—essentially, a state-of-the-art digital camera.It automates the job of finding supernovae.Telescopes now take thousands of pictures, and computers are used to spot bright spots that indicate a supernova explosion.Over five years, Perlmutter and his colleagues at Berkeley used the new technique to discover 42 supernovae.Today, even amateurs are using charge-coupled devices to spot supernovae. "With a charge-coupled device, you can point a telescope at the sky and walk away to watch TV," Evans said grimly. "The smell of magic is gone." I asked Evans if he wanted to adopt this new technology. "Oh no," he said, "I like the way I do it, and," he smiled, nodding to a recent photo of a supernova, "sometimes I can still outrun them." The question naturally arises: what would happen if a star exploded nearby?We already know that the nearest star to us is alpha star, which is 4.3 light-years away.I used to imagine that if there was an explosion there, we could see the light of the big bang sprinkled all over the sky for 4.3 years, as if poured from a large can.What if we had four years and four months to watch an inescapable doom looming toward us, knowing that when it finally arrived it would scrape our flesh from our bones?Will people still go to work?Will farmers still grow crops?Does anyone else ship produce to the store? A few weeks later, back in my small New Hampshire town, I posed these questions to Dartmouth College astronomer John Thorsteinson. "Oh, no," he said with a smile, "the news of such a big event will travel at the speed of light, and the destruction, you will be scared to death when you hear it. But don't worry, this kind of Things don't happen." As for the shockwave from a supernova explosion killing you, he explained that you have to be "ridiculously close" -- probably within 10 light-years or so. "The danger comes from all kinds of radiation - cosmic rays and so on".The radiation produces stunning auroras, eerie curtains of shimmering light that fill the sky.This is not going to be a good thing.Anything capable of staging such a scene would wipe out the magnetosphere — the magnetic field high above Earth that normally shields us from ultraviolet light and other cosmic assaults.Without a magnetosphere, any unlucky person stepping into sunlight would quickly look -- say -- like a burnt pizza. There's reason to believe that this kind of thing doesn't happen in our part of the galaxy, Thorstein said, because, first of all, it takes a special kind of star to form a supernova.A star would have to be 10-20 times the size of our sun to qualify, and "there isn't any planet near us that fits that bill".As luck would have it, the universe is a big place.He went on to say that the closest thing to us, and probably eligible, is Orion, which has been getting everyone's attention for years by spewing out things that indicate instability there.However, Orion is 50,000 light-years away. In recorded history, there have only been half a dozen supernovae close enough to be seen with the naked eye.One was the explosion in 1054, which formed the Crab Nebula.Another time, in 1604, created a star so bright that it was visible even in daylight for more than 3 weeks.Most recently, in 1987, a supernova flashed through a region of the universe known as the Large Magellanic Cloud, but it was only barely visible, and only from the southern hemisphere—it's 169,000 light-years away and to us There is no danger. There is another aspect of supernovae that is absolutely important to us.If there were no supernovae, we would not be in this world.You'll recall that towards the end of Chapter 1, we talked about the mystery of the universe -- that the Big Bang produced a lot of light gases, but no heavy elements.Heavy elements came later, but for a long time no one could figure out how they came about.The problem is, you need something that's really hot -- hotter than the center of the hottest star -- to forge carbon, iron, and other elements; will exist.Supernovas provide an explanation.This explanation comes from an almost Fritz Zwicky-like eccentric British cosmologist. He was a Yorkshireman named Fred Hoyle.Hoyle, who died in 2001, was described in a eulogy in Nature as a "cosmologist and debater," and he deserved both. A eulogy in Nature said he "was embroiled in controversy for most of his life" and "discredited himself".He claimed, for example, that the Archeopteryx fossil held in London's Natural History Museum was a fake, much to the chagrin of the museum's paleontologists, as was the case with the Piltdown Man skull hoax.They had to spend days answering calls from journalists from all over the world.He also believed that Earth received not only the seeds of life from space, but also many of its diseases, such as colds and the bubonic plague.He also once suggested that humans evolved with protruding noses and downward-facing nostrils to prevent cosmic pathogens from falling in. It was he who coined the name Big Bang as a joke in a 1952 radio script.He pointed out that in our understanding of physics, we can't explain why everything converges to a point and then suddenly and dramatically starts to expand.Hoyle favored the steady-state theory, which holds that the universe is constantly expanding, creating new matter in the process.Hoyle also realized that when a star implodes, it releases a lot of heat—more than 100 million degrees Celsius—enough to produce heavier elements in a process called nucleosynthesis. In 1957, Hoyle, among others, showed how heavy elements are formed in supernova explosions.For this work his collaborator WA Fowler received a Nobel Prize.Hoyle didn't, embarrassingly. According to Hoyle's theory, an exploding star would release enough heat to create all the new elements and sprinkle them across the universe.These elements form clouds of gas -- the so-called interstellar medium -- that eventually coalesce into new solar systems.Armed with these theories, we can finally construct a plausible scenario for how we came to be in this world.Here's what we now think we know: About 4.6 billion years ago, a gigantic eddy of gas and dust about 24 billion kilometers in diameter accumulated in space where we are now and began to accumulate.In fact, all the matter in the solar system -- 99.9 percent -- was used to form the sun.Among the remaining floating matter, two particles floated in close proximity and were attracted together by static electricity. This is the moment of gestation for our planet.The same is happening throughout the nascent solar system.Dust particles collide with each other, forming larger and larger clumps.Eventually, these clumps get large enough to be called planetesimals.As these planetesimals collide endlessly, they break apart, disintegrate, and recombine in endless and haphazard permutations, but each collision has a winner, and some winners get bigger and bigger until they dominate. the orbits they run on. This all happened fairly quickly.It is thought that it takes only tens of thousands of years for a small cluster of dust grains to become a baby star with a diameter of several hundred kilometers.In just 200 million years, probably less than that, the Earth was basically formed, still hot and constantly pummeled by debris still floating around. At this point, about 4.5 billion years ago, a Mars-sized object crashed into Earth, blasting off enough material to form a companion star, the Moon.It is thought that within a few weeks, the blasted material had regrouped; within a year, it had become the rocky sphere that is still with us today.It is thought that most of the material that makes up the moon comes from the crust, not the core, which is why there is very little iron on the moon, while there is a lot of iron on the earth.Incidentally, this theory is almost always said to be recent, when in fact it was first proposed by Reginald Daly of Harvard University in the 1940s.The only recent thing about this theory is that people don't take it seriously anymore. When the Earth was about a third of its final size, it likely had already begun to form an atmosphere, mainly composed of carbon dioxide, nitrogen, methane and sulfur.We would hardly associate these things with life; yet, out of this poisonous concoction, life formed.Carbon dioxide is a potent greenhouse gas.It was a good thing because the sun was much weaker then.If we hadn't benefited from the greenhouse effect, the earth would probably have been permanently covered in snow and ice.Life may never find a foothold.However, life somehow appeared. For the next 500 million years, the young Earth continued to be pummeled relentlessly by comets, meteorites, and other debris from the Milky Way. This process produces the water that fills the oceans, producing the ingredients necessary for the successful formation of life.It was an extremely unfriendly environment, yet somehow life began.A little bag of chemicals twitches and comes alive.We are coming to this world soon. Four billion years later, people start to wonder, how the hell did this happen?Next, let's talk about this story.