(Morrow, 1988, 495pp, including 107pp of appendices (a glossary and a timeline history of the universe), notes, bibliography, and index)
This is the first big substantial nonfiction book I’ve read in a while, especially one specifically about science. Ferris is a science writer who began with THE RED LIMIT (1977) which I read years ago, a couple coffee table books of astronomical photos, GALAXIES and SPACE SHOTS, in the early 1980s, before this book in 1988. And I have three of his later books that also look substantial, and that I’ll get to eventually.
This book speaks to one of my key interests: how humanity came to understand how big, and how old, the universe is. The ancients (like those who wrote the holy books) knew a world only as big as the far horizon, and as old as their oldest stories. I’m already familiar with many of the steps between then and now, through accounts in any number of books about basic science, but here the whole story, along axes of space, time, and creation, is summarized, with a particular emphasis on both the techniques that revealed humanity’s increased understanding of the real world and on the individuals who made these discoveries. There’s much more about the personalities of famous names from history here than in those other books.
And I particularly appreciate the theme represented by the title. The gradual realization of the actual nature of reality has been a kind of maturity of humanity. By comparison, the ancients were ignorant children. That modern culture retains both perspectives says something about education, perhaps, or more likely my thesis that most people even in our modern age get by quite nicely without knowing anything about the world outside their immediate experience.
(Note that I wrote about this book last September when I began reading it, at the bottom of this post, drawing some comparisons between the stages of awareness of learning about the cosmos and the way cognitive biases hide aspects of the world from us. How the gradual corrections to ancient thoughts about the cosmos mirror attempts to correct tribal morality (racism, etc.) via democracy and enlightenment values. And along each of these paths, conservatives reject the advances, in favor of a flat earth and conspiracy theories about faked moon landings on the one hand, and attacks against anything “woke” (non-tribal) on the other. There may be no escaping base human nature.)
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For this book I’ll copy all 7200 words of the notes I took while reading it, clean them up, then highlight key names and phrases so that you or I can read a summary of the book later just by skimming the bold spots.
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Preface and acknowledgements, p9
This book is about how, through science, our species has come to understand our current estimate of the dimensions of time and space. While striving to be brief. Leaving out the dead ends that were part of the history of science. 10t. Leaving out the original intentions of scientists who later became known for different things. And simplification, for the lay reader. Written over 12 years. Credits Druyan, Gould, Hawking, Pagels, Sagan, Thorne, Weinberg, among others.
Part One: Space
1, The Dome of Heaven, p19
How the ancients climbed ziggurats to be that much closer to the stars; they figured they were only slightly out of reach, as with (Daedalus). They spent a lot of time learning the movements of the stars and planets. They watched with a kind of reverence. This knowledge was useful for navigation, and timekeeping. Examples of poetry and testimony. Stonehenge, the Great Pyramid at Giza, others. The ability to predict gave power to Columbus, foretelling a lunar eclipse to impress the natives. But planetary movement could be complicated: precession of the equinoxes. They didn’t realize the planet Earth was also in motion. Only gradually were models of the universe required to be predictive.
Eudoxus, 385 bc, came to Plato’s academy to study geometry. Plato regarded geometry almost as theology; he was obsessed with perfection. Eudoxus studied the sky, and constructed a model of concentric spheres around the earth. With additional spheres to account for retrograde motions. 27 in all. Even this model was inadequate, when Babylonian records were accessed. Then came Aristotle, relatively empirical, but also obsessive and certain about everything to the point of credulity. He founded his own academy and came up with a new model that mislead the world for centuries. Earth at the center, 55 spheres, and nothing beyond the outermost sphere. The model became even more complicated, with Ptolemy, 2nd century AD, using epicycles and eccentrics. He sometimes fudged data. The price for precision was any claim that it represented physical reality. It was to “save the appearances.” Plato distrusted books; see 31b about how writing was denounced. This problem has never gone away, with modern philosophers of science struggling to see science as something other than interpretive devices.
2, Raising (and Lowering) the Roof, p33
Their earth-centered universe might have been fifty million miles in radius. This size reflected how fast the stars must be moving to rotate in each day. The idea that the earth might be in motion was rejected, given that there were no huge winds and so on. (They had little concept of inertia.) To think that the earth might orbit the sun makes the problem even more difficult; the earth would swing closer to one side of the stellar sphere, and then the other. But they didn’t all think that way; the exception was Aristarchus, from Samos, who had a heliocentric model. We know of him via Archimedes in 212 bc. Archimedes began by estimating the number of grains of sand on the beaches of the world, 37. Using ideas from Aristarchus, he calculated the distance to the sphere of stars to be about six trillion miles, or one light-year. But Aristarchus was largely forgotten, and it took a millennium before Copernicus came along; Ptolemy proved more popular. M/w Archimedes designed war machines to fend off the Romans. He was cut down by a Roman soldier while drawing diagrams in the sand. And around this time Greek science gave way to Alexandria, with Ptolemy I, Euclid, Eratosthenes, for a century or two. The Romans conquered the world by 30bc, and theirs was a nonscientific culture, instead revering authority. 41t notes. Science fared no better under Christians, p42t:
Christianity, in its emphasis upon asceticism, spirituality, and contemplation of the afterlife, was inherently uninterested in the study of material things. What difference did it make whether the world was round or flat, if the world was corrupt and doomed?
The library in Alexandria burned. Christian and Muslim activists. Hypatia was slaughtered by a Christian mob. Scholars fled to Byzantium. Islam then pursued science; we see this in the names of stars. They admired Ptolemy’s universe. But were dismayed by the complexity of all those spheres and epicycles. The last classical scholar in the West was Boethius; samples of his writings. Note 44b passage about the small portion of Earth that people live in. And then came the Dark Ages. Churchmen imaged the universe as a tent, the planets pushed around by angels. And the earth flat. Only heaven lay above.
Ch3, The Discovery of the Earth, p47
Exploration of the earth began with Marco Polo in the 13th century and culminated 200 years later with Columbus. People had navigated by the stars for centuries. Virgil on the founding of Rome. And examples of American Indians. Of Toscanelli, an astronomer who wrote to Columbus. Polo was impressed by Hangchow; two islands in the middle of a lake. Europeans had reason to reach China by sea. Africa was explored… dangers encountered. Map p53. Portugal found gold, and slaves, a million of them. The Chinese had already discovered Africa’s east coast, less violently. Columbus had been a solder, and survived the burning of a ship at Cape St. Vincent, feeling himself on a mission from God. He was an anachronism, 54b. He and other Europeans felt they were bringing salvation to the Africans. Columbus was after riches, wisdom, and to prove the world was small (everyone already knew it was round). He fashioned numerous arguments to conclude so. God was right and the professional geographers were wrong; the latter said the voyage would take 3 years. (As Magellan’s did.) The Queen gave him a shot at it, so he sailed in 1492. He was zealous in his resolve. His ships found America, which Columbus believed was India to his dying day. Later he thought the world was shaped like a pear (bigger around at one end than at the other). He gradually went mad over subsequent voyages. Later explorers were focused on gold. Cortez killed Montezuma. Pizzaro killed Atahualpa of Peru. The Old World prospered. Navigation became widely taught. Dimensions of the Earth doubled. They realized up and down were relative. Leonardo wrote about it. And Copernicus.
Ch4, The Sun Worshipers, p61
The supernova of 1572. Kopernik, born just thirty years after the invention of the printing press, allowing the classics to become cheaply available. K read a lot of books. He became Copernicus. He had his own library. He admired Ptolemy. But was aware of his system’s inaccuracies. The Renaissance, re-birth, was mostly about rediscovering old wisdom; the radiance was in the past. [[ the good old days! ]] Aristotle was revered, and incorporated into the Catholic worldview via Aquinas. C was looking for a simple underlying structure to the universe. This was how he decided to put the sun at the center of the universe. And there was a sort of sun worship as Christ was being modeled on busts of Apollo (the sun god). But his model didn’t work much better; he presumed spheres, and circular orbits. He needed epicycles too. The observations did not agree. He put off publishing his work until he was on his deathbed. He feared religious authorities, who invoked “sacred Scripture.” But the professionals paid attention. His model enabled measurements. But they were proportional. Then came comets, and two novae. Aristotle separated the universe into two realms, the earth, composed of four elements, and the heavens, composed of aether. That appeals to Christians. Aristotle thought comets, and meteors, atmospheric phenomena. But Tycho took measures and found that comets must be far away.
Then came the supernova of 1572, and another in 1604. Neither moved in the sky. They too, were far away. Tycho discovered many inaccuracies in Ptolemy’s predictions. He was rich, and built an observatory p72, and took thousands of observations over 20 years. He proposed a hybrid model of the solar system, p73. And he hired Kepler, in 1600, a poor man in comparison to Tycho’s wealth. Kepler had the notion of the orbits of the planets fitted like nested Platonic solids; it was wrong. But he believed in the beauty of the world. The idea of ‘celestial harmony’ appealed to him, p75. The idea was in the air – Milton, Shakespeare, the polyphony of church music. But he was rigorous about theory, and needed better data—which Tycho had. But the two quarreled constantly. Tycho allowed Kepler only to study Mars. Tycho died; Kepler plowed on, sacrificing the idea of circular orbits. And hit upon the ellipse. And eventually, what are known as Kepler’s laws. P80-81. He was happy; he had discovered order and beauty. Tragedies followed in his life. He moved back to his village, and wrote his Somnium. He died at age 48.
Ch5, The World in Retrograde, p83.
Einstein quote about how only empirical knowledge, not pure logical thinking, yields knowledge of reality. And how Galileo saw this.
Galileo came to symbolize the important of observation and experiment. Galileo and the Inquisition became the symbol of the conflict between science and religion. But some stories are apocryphal. He was born 1564. He campaigned against authority, and the value of asking any kind of question. (Aside about the prohibition of dissecting bodies by the Church p85) A troubled career was saved by his discovery of the telescope. They were useful as lookouts for the city of Venice. (But he didn’t actually invent it.) He used it to look at the night sky. The moon. Jupiter, and four moons. Venus, with phases. And the stars, in a sky with depth. The Milky Way as stars. In 1610 he published Starry Messenger. The challenge for science was to explain why the Earth acts as if it is at rest. He wondered if the commonsense view that heavier objects fall faster was wrong. He used ramps to demonstrate so. And he conducted thought experiments, p91.He wondered about gravity, and inertia.
But Galileo was still hung up on Aristotle’s notion that objects have a ‘desire’ to move or stay put. Kepler had some adjacent ideas; they never completely agreed. Galileo was urbane, and looked down on Kepler. Galileo tried to convert the Catholic church to Copernican cosmology, based on his own book. Note it wasn’t the clerics who refused to look through Galileo’s telescope; it was academics, who felt threats to their own authority. And the church required proof. Galileo had analogies, but no proof. The result was that Copernicus was put on the list of forbidden books. A friend of Galileo’s became Pope Urban VIII. Galileo wrote a ‘dialogue’ on the two systems. Galileo was politically naïve, and got into trouble, which the pope did not help with; he went before the Inquisition and was forced to abjure Copernicanism. He remained under house arrest, and went blind. Milton admonished against cosmological speculation.
Ch6, Newton’s Reach, p103
Newton then created a mathematical system to describe gravity both terrestrial and celestial; no more two realms. He was a strange individual. He studied alchemy and biblical prophecy too. An only child. Sensitive. He read books. Descartes. Lived to age 85. He accomplished much early on, but didn’t publish, so as not to attract fame. During the plague he went home, where he hit on his grand theory of gravitation. He saw an apple fall out of a tree. He deduced the force of gravity, but didn’t publish it. He was an eccentric academic. Notoriety eventually came via a telescope. He invented a new kind, the reflecting telescope. He was elected to the Royal Society. (One of several such societies, 111.3). Details p112. Halley resorted to visiting Newton with a question about inverse-square and orbits. Newton had to recreate his calculations; once he did, he wrote his Principia. Which laid out his three laws. Which explained the solar system. Halley got it published. Newton was not like other men; he was indifferent to music, sculpture, poetry. He died a virgin. He knew mysteries remained, e.g. the mystery of gravity itself, of cause at a distance. Nor could he hope to calculate precisely all the orbits of the planets—the ‘many body problem.’ And he left theological problems. Science was a form of worship. Even as his mechanics seemed to defy free will.
Ch7, A Plumb Line to the Sun, p123
By the beginning of the 18th century the proportions of solar system were known, but not its actual scale in terms of distances. Only in terms of astronomical units. If that were known, distances to other stars might also be calculated. The ancients had figure the distance to the sun of some 4.8 million miles. There were two ways of measuring distances: micrometry, and triangulation (parallax). Example parallax of Mars, p126. Mechanisms to do the latter came from navigation. Of longitude in particular. Sextants. Prizes were offered by many nations for a solution. ‘Watches’ were invented. Maps were improving. Expeditions were sent to triangulate Mars and Venus. A transit of Venus was observed in 1761 and 1769. Earlier transits had been haphazardly viewed. These were heavily observed. But many expeditions failed in various ways. The most elaborate went to Tahiti. They took nails to trade with the natives. The results were good, and were refined in later centuries. The solar system came to be known as nearly 100 times the Ptolemaic estimate of the entire universe.
Next: distances to the stars. First they tries apparent magnitude compared to that of the sun. to triangulate they would use the orbit of the earth as a baseline. Stellar parallax. This required clearing up some issues with earth’s motion. One try involved a ‘zenith telescope’ pointing at Gamma Draconis. That and other stars seemed to wobble daily! Due to the earth’s motion, what came to be called the aberration of starlight. But very exact measurements were needed. It was in 1838 that the parallax of 61 Cygni was obtained. That and other stars, light years away. Scales were vast. Later, it was understood how iron plays a central role in the evolution of stars. Heavier elements from light ones, up to iron. Then the stars would explode and those elements would settle into planets, like earth.
Ch8, Deep Space, p143
Nebulae, those patches of light in the sky, are actually three different things: shells of gas thrown off by their suns; clouds of gas illuminated by nearby stars; and then the elliptical and spiral nebulae, which are actually huge galaxies millions of light years away. It took understanding what these nebulae were before we appreciated the immensity of space. The first steps were taken by Kant and Lambert. A young Kant. A review of a book by Thomas Wright triggered ideas about the cosmos being a sphere. The review actually misrepresented Wright. Or about the milky way being disk shaped. And from that, the idea of a universe full of galaxies. Those elliptical nebulae, in their various shapes. The book ws published but seized in bankruptcy; no one saw it. Frederick the Great had a similar idea, from a roomful of candles, interviewing Lambert. Who also had a theory about the Milky Way. He came to Herschel… who loved music but was better at astronomy. He read Ferguson, about nebulae. Larger telescopes were needed. Herschel used larger and larger refractors. Some without tubes. He finally switched to reflectors. He took to grinding mirrors, with his sister’s help. He would ‘sweep’ the sky. He memorized the sky. He discovered Uranus. Eventually he had a 48-inch reflector built. He observed the Messier objects, concluding most were stars. And the Orion Nebula. He tried charting the entire galaxy. He looked at Andromeda. His approach to astronomy was modern. He realized he was seeing ancient light. He worked until he died, in 1821.
Ch9, Island Universes, p161
There were two schools of thought about the elliptical nebulae. One, that they were ‘island universe’ like our own Milky Way; two, that they were whirlpools of gas condensing into stars. Both were sorta right, for different nebulae. The riddle was solved with the spectroscope. Newton saw the rainbow through a prism in 1666. 1802, dark lines in the spectrum. Joseph Fraunhofer was an optician in Munich. He studied the dark lines, saw that other stars had different lines than the sun. He died in 1826. Later Kirchhoff identified various elements in the sun’s spectrum. In London Huggins studied the spectra of stars and nebulae. He jumped to the conclusion that all the nebulae were clouds of gas, not stars. It was still assumed that our sun lay at the center of everything… that included everything visible in the sky, 166.7. But evidence shifted. But then records of exploding stars suggested some of those nebulae were stars too. A project to chart the location of the solar system in the Milky Way began, championed by Hale at Mt Wilson, then Harlow Shapley, who studied variable stars, including the Cepheid variables. In those stars the length of a cycle of variation is related to its absolute magnitude. Thus their distances can be deduced. The actual discovery came from a female ‘computer’ at Harvard, looking at plates of the southern sky. Shapley took the idea to calculate the distances of globular star clusters. It didn’t take long. He found the clusters in roughly a sphere, whose center was nowhere near the sun. Perhaps the center of the galaxy. The solar system was thus nowhere near the center of the galaxy. But the figures indicated the Milky Way was much larger than previously thought. Though his own numbers were off. Not everyone was convinced. … Hubble was Shapley’s nemesis. He eventually found a Cepheid variable in the Andromeda Nebula, and deduced it was 1 million light years away. That led to the conclusion that we live in one among many galaxies. Thus establishing a uniformity of the laws of nature. Later refinements were made to the distance scale. Measurements were made of galaxies millions and even billions of light years away – and of what they looked like that long ago. The first sign of that were the quasars, in the 1960s. We now have a good idea of the sun’s place in our galaxy, and what galaxies lie far away; the Local Group, the Virgo Supercluster, and other clusters, which together seem to be arrayed in a giant domain that resembles cells of a sponge.
Ch10, Einstein’s Sky, p177
Einstein’s physics enabled understanding of the cosmos as a whole. He abandoned Newtonian ideas of space and time. Rather, time flows at a rate depending on relative velocities; space is curved and that curvature explains gravity. Newton had postulated the aether. That became a problem when measuring the velocity of light. Attempts had been made. The velocity of earth through the aether was tried. Michelson and Morley showed no such ‘aether drift’. Did the apparatus contract? No. Einstein was born in 1879… cut classes, etc. Became a tutor. Then the Swiss patent office. In 1905 he wrote four papers, two laying out special relativity. Early on Einstein wrote hymns to God; at age 12 he discovered geometry, his conversion text. 184. He was tenacious. At 5 he was entranced by a pocket compass; “something deeply hidden.” Faraday had studied magnetism and electricity. Maxwell came along to write equations about them. The concept of fields. Light as a kind of electromagnetism. The equations struck Einstein like a revelation. As it turned out, Maxwell’s equations and Newton’s absolute space were paradoxical. Einstein realized this. His own family built dynamos. They weren’t well understood. Einstein’s career was up and down. He enjoyed the patent office. He read Mach. He formulated his theory, including that the speed of light was the same for everyone. He used the Lorentz contractions. Details: mass increases as speed increases; acceleration beyond light speed is impossible. These effects have been confirmed in countless experiments. The ideas struck most people as very strange. Einstein wrote that inertial mass increases as an object absorbs energy. Mass and energy are interchangeable; thus that equation. Matter is frozen energy. But gravitation was left out of all this. They seem to be two separate things; yet inertial mass is equal to gravitational mass. Einstein took up the idea, leading to general relativity. A key thought occurred in 1907. Thus the thought experiment of being in a falling elevator. This led to the concept of four-dimensional spacetime. His instructor Minskowski had suggested that time could be treated as a dimension. [[ and Wells suggested the same, in 1895 ]] Einstein needed non-Euclidean geometries. Figure, p198. Principles had already been worked out. Einstein tried to assign time as the fourth dimension. After much struggling he finished in Nov 1915. It resolved the problem of whether the universe infinite. With infinite gravity and infinite light. The problem went back to Lucretius. The solution was the universe is finite, but unbounded. Space wraps around itself. Just as the earth is finite and unbounded. 202 diagram. (Or, it could by hyperbolic, infinite and unbounded.) Einstein was confident. Experiments were done; 1919, to test the curvature of space near a solar eclipse. Einstein was so confident he went to bed…
Ch11, The Expansion of the Universe, p205
The theory implied the universe could not be static. No one and thought about this before. Einstein added his cosmological constant. Then in 1917 the first observational evidence came of an expanding universe. Spectra of spiral nebulae showed enormous shifts toward the red end of the spectrum. They must be Doppler shifts – galaxies moving away at millions of miles an hour. Enter Hubble, who used Cepheid variable to establish distances, and thereby to correlate distance with recession velocity. This was consistent with general relativity without the fudge factor. But Hubble was unaware of the theory. It took an obscure Belgian to bring the theory and observations together. Eventually they learned of each other. The Belgian, Lemaitre, then thought about how small the universe might have been before expanding. This didn’t appeal to Eddington. Lemaitre persisted, speculating about a ‘primordial atom’, which Hoyle mocked as a big bang. Einstein left Germany for California, and saw the evidence. Lamaitre wrote a book, and nuclear physicists got involved to speculate about the first moments of the big bang. Such as Teller, and Gamow. Gamow wondered if elements were formed in the early universe. And speculated about the residual heat, which he guessed might be about five degrees. It took a decade for radio telescopes to become a reality. And Penzias and Wilson heard the interference that indicated a temp of 2.7 degrees.
Summary: the expanding universe rests on three lines of research: The Hubble law, the cosmic background radiation, and the consistency of the age of the universe with the oldest stars. So next we examine how we came to understand cosmic history.
Part Two: Time
Ch12, Sermons in Stones, p217
The ancients held a concept of time from the Chaldean belief that time was an endless cycle of ‘great years’ each ending when all the planets came together, creating a catastrophe from the ashes of which the next cycle began. Forever. Example of Islamic fable about eternal recurrence—how despite that things do change, people think they’ve been like they are now forever. The idea is present today in notions of oscillating universes. The idea undermines trying to determine how old things are. The Greeks knew that the world changes. they knew mountains can be thrust up by the sea, and be worn down by wind and water. The notion of linear time came with the Christian model of the universe. Theirs was abbreviated and anecdotal, in which the affairs of men and God were more important than the wind and the rain. Christians added up ‘begats’ in the Bible to determine the age of the earth, culminating with Bishop Ussher and his 4004 bc date. However absurd many found that claim, it inspired scientists to study stones, not scriptures. Example 1778 of this approach. Steam engines played a role: the cutting of canals and laying of tracks split open the surface of the earth. Werner and Smith in 1793 noted that the same strata appeared in the same order in widely separated locations. And that some strata had particular fossils. These fossils also revealed creatures not alive today. This challenged the Biblical view of creation, especially as the world’s wildernesses were explored and no woolly mammoths were found, e.g. Missing species numbered 23 by 1801. By now we know that 99% of all species that have ever lived have died out. The variety of *living* species was also a puzzle to Christians. The religious took refuge in a ‘great chain of being’ with humans at the apex. Except that there were missing links in this chain. The prospect of extinction was rejected. The evidence became more and more obvious that there had been plenty of extinctions. 224.4. Could all of this have happened within 6000 years? Fundamentalists resorted to ‘catastrophism’, with events like the Flood. But this ruled out studying the past. Lyell instead held a uniformitarian view: all changes in geology and biology were due to ordinary natural causes. James Hutton was a proponent of this view. His view in a diagram, p226. But this required the earth to be very old. Hutton even suggested an infinite past. Later, Lyell took up the argument. He noticed erosion at the coast compared to his childhood. He actually wandered the earth, unlike armchair theorists. He climbed Mount Etna, went to Chile, saw the effects of volcanic eruptions and earthquakes. And he argued well against the catastrophists. And suggested the earth might be millions of years old. It wasn’t one idea over the other, he said, it was the willingness to be open to evidence even when it contradicts an existing consensus. Then came Charles Darwin, 1831, setting sail on the Beagle.
Ch13, The Age of the Earth, p231
Darwin read Lyell’s book on his voyage. Darwin began his own hypothesis from Lyell: the world is old and continually changing. On the trip he witnesses the effects Lyell saw. After four years he began by speculating on the origin of coral atolls. That they were vanished volcanoes. A gradual process. By the time he returned Darwin was much changed. When he’d left he was a creationist, a Biblical literalist. He returned home a doubter. The idea that species could change was not a new idea. He was familiar with his grandfather Erasmus Darwin, and with Lamarck. Darwin contributed the mechanism for how new species came into existence. Variation; that creatures produce more offspring than can survive (as Malthus pointed out); and that these result in what he called ‘natural selection’. (Example of those brown and white moths in 1849.) And that this explains the origin of new species. This is the tree of life come alive.
Critics said natural selection was cold and mechanical. Darwin thought differently, p239. He outlined his theory in 1844 but didn’t publish for 15 years. Yet he wrote much else. Why? Likely he feared opposition to his ideas. Especially religious opposition. And from scientists devoted to scriptures. And there were crackpots advocating various notions of evolution. Darwin admittedly he didn’t know how heredity worked (i.e. no one knew about genes). Evidence for genes appeared eight years later, from Mendel, but was ignored until 1900. Darwin began writing a detailed account, when a letter arrived from Alfred Russel Wallace detailing the same theory. Darwin was tempted to give all credit to Wallace, but Lyell and Hooker persuaded to write a brief account for prompt publication. This became The Origin of Species. It was detailed and bloodless. It was so detailed the idea struck many as self-evident. Religious reaction was predictable, but overplayed. Example of Huxley and Wilberforce, 245. The drama was played out when Darrow defended Scopes. And into the 1980s.
Darwin’s theory impacted ideas about the age of the earth. Vastly longer than 6000 years. Proof of that came from the physicists, who knew that the earth radiated heat into space. Experiments began in the 1770s. 246. Attention turned to the sun. What powered it? Gravitational contraction? That implied 20 to 40 million years. Kelvin took the subject up. He got 500 million years. Something was missing. Darwin died not knowing what. That was nuclear energy. Nuclear fusion has kept the sun going for 5 billion years. The nuclear age began in 1895, when Rontgen discovered “X rays.” Others investigated similar glowing objects. Becquerel, Rutherford, radioactivity. And the time for Darwin’s ideas to work. And gave a way to measure the age of the earth, through radioactive decay. Carbon-14 was useful, with a half-life of 5570 years. Other elements have different rates of decay. By the 1920s it was accepted that the Earth and solar system were billions of years old, consistent with astrophysicists who said the sun is a normal star half-way through a 10by lifespan. Nuclear fission and fusion were discovered in the 1930s, and the bomb was dropped on Hiroshima in 1945. Only a few warned of the potential consequences. Nations built nuclear bombs rapidly. Truman warned of future wars. And later presidents kept threatening the Soviet Union with them.
Ch14, The Evolution of Atoms and Stars, p255
What then powered the sun and stars? The key was to understand the structure of the atom, following the implications of radioactivity. Experiments shooting alpha particles implied that most of the mass of an atom resided in a tiny nucleus. In turn, this explained the weights of the elements. Niels Bohr established that electrons inhabit discrete orbits, or shells. And so on, the basis of chemistry. Wavelengths, the spectrum. That still didn’t explain why stars shine. At Harvard, ‘computers’ catalogued hundreds of thousands of spectra. As these were sorted, patterns emerged, and a classification system, from O through G to M. Then the Hertzsprung-Russell diagram emerged to relate class to brightness. 261. Eventually this gave distances to many stars. On the physics side progress was blocked by the Coulomb barrier. Reasoning about atoms and colliding protons. Fusing into heavier elements releases energy. But protons repel each other. The solutions came from quantum mechanics. Movement is probabilistic. Quantum tunneling. Gamow, and then others, accounted for how this tunneling enables the energy of the stars. A few more years, two fusion processes were identified. Hans Bethe… all solved by 1938, in a paper that won him a Nobel Prize. A sequence of fusion reactions, 264.
Once this was established, they could rework the estimate of the age of the sun. the composition, density, temperature. The lifetime turns about to be about 10 billion years. And for other stars. Dwarf stars last much longer. Huge stars last under 100my. Stars die in different ways. From red giants to white dwarfs. Moving around the main sequence on the H-R diagram. And the diagram can be aligned to age, p269. The Pleiades is a young cluster. Globular cluster M3 is 14byo. Vision of how the sky would look if a billion years went by in an hour. P270. The stars also build up heavier elements from the lighter ones. Making elements is what stars do. But how exactly? Or were some elements fused in the big bang? Gamow worked on this but had troubles. Only helium could be created in the big bang. And Fred Hoyle didn’t like the idea of the big bang anyway. And there were errors in the calculation of time since the big bang. Hoyle and others came up with a steady state model. Then where did the elements come from? The stars. Hoyle showed how some the elements could be made that way. Maybe in supernovae. Clues came with the detection of californium in the Bikini Atoll bomb test. Then came the cosmic abundance curve. P278. They finished their work in 1957. A timeline emerges. Details 279. Some stars become neutron stars. When it explodes, heavier elements are created. The explosion creates interstellar clouds that then condense into planets. Diagram 281. …
Part Three: Creation
Ch15, The Quantum and Its Discontents, p285
Exploration changes people; some old ideas have to be left behind; others altered. The Newtonian universe was a parochialism. The subatomic realm also brought a revolution, of quantum physics. Max Planck, 1900, studying black body radiation. Quantum theories soon spread throughout physics. Heisenberg identified the indeterminacy principles in 1927: you can know position or trajectory, but not both. (Because either measurement affects the system.) Note chart p287, scale of the known universe. Electrons move between ‘orbits’ without traversing the intervening space. Plenty of people find these ideas nonsensical. (Because we grew up in the macroscopic world, 288b.) Most matter is empty space. The quantum revolution delivered us from several illusions of the classical world view. We cannot objectively observe anything; the observer is not separate from the observation. Similarly with causation; what we thought was deterministic is actually only probable. This troubled Einstein, and remained sure it would be superseded. But strict causation can sound monstrous, 291t, of a universe predictable in past and future? No free will? QM brings the return of chance. Anyway, quantum physics works. Though it became so complex, with all those particles, some just quit science. But its predictions worked; it was “one of the greatest intellectual achievements in the history of human thought.” 292.3. The standard model, by the end of the 20th century, consisted of fermions and bosons, depending on spin; they compose matter and force respectively. There are four fundamental forces: gravitation, electromagnetism, and the strong and weak nuclear forces. Their ranges are different. The forces are carried by particles like the gluon and the graviton. Some of the particles are massless. Quarks are bound up inside protons and neutrons. Fermions are quarks or leptons. Pp294-5. QED, QCD. Gravitation is not covered by these theories. As of the late 1980, the model is a crazy quilt. It’s not complete. It’s too complicated. Physicists want something simpler and beautiful. A ‘unified’ theory is sought.
Ch16, Rumors of Perfection, p301
So physicists are guided by aesthetic principles as well as by rational concerns. Dirac emphasized the need for beauty in a theory. Which is what? Symmetry. Repetition. And proportionality. In science, when a measurable quantity remains invariant under a transformation, 302b. Examples of a sphere… architecture, music. Bach, Debussy. Spiral patterns in plants. Fibonacci numbers, the golden section, the musical octave. Some symmetries were found in the laws of nature. Einstein looked for them. They apply to the quantum fields of particles and fields. Doing this led to the prediction of antimatter, new particles, and to new fields. Gauge field theory. Yang, in China, searched for an invariance in the strong nuclear force. A force expresses a symmetry… A symmetry implied the existence of particular particles. Murray Gell-Man used this approach. He was brash. He found a symmetry group that implied quark theory. Later broken symmetries were detected. Asymmetries led Weinberg and others to a unified electroweak theory. Weinberg was self-disciplined. Glashow was easy going. A problem with electroweak theories was nonsensical infinities. But they can be cancelled out. Glashow hooked up with Abdus Salam, who proved a renormalization. … Weinberg had an insight… 1967. He and Salam won the Nobel. To test it, particle accelerators were needed. CERN and Fermilab competed. Descriptions of each. They raced to test the electroweak theory. CERN found the first evidence. Both facilities needed to upgrade, e.g. to use antiproton collisions. Carlo Rubbia at CERN. They put antiprotons in a storage ring. It was a controversial idea that some dismissed. CERN built it. Tests began in 1982, and it worked. And they detected the W particle. A larger CERN accelerator was begun. Theorists began proposing various ‘grand unified’ theories (GUTs). They predicted that protons would eventually decay. Detectors were built but no evidence found. Other theories were proposed, ‘supersymmetry’ theories in the 1980s; they stalled. What was missing? Perhaps string. Extremely small, but which can vibrate, and rates of vibration could generate the properties of all known particles. Problems with infinities went away. And it somehow included gravity. And it required the universe to have at least 10 dimensions. Weinberg promoted the idea. By the late 80s scores were working on the idea. Yet earlier tries at a unified theory went nowhere. Critics of string theory said there was little to it but internal beauty. It made no predictions. Some predicted it would become a theology. Perhaps the theory indicates that our world is debris from a higher-order one, and more might be found: shadow matter. Perhaps the supersymmetric universe exists only in the past…
Ch17, The Axis of History, p335
Thus in the late 20th century particle physics and cosmology joined to become the study of the universe as a whole. Cosmologists tend to be loners; physicists, gregarious. The two studies met with the big bang. The high-energy early universe had symmetries that have since become broken. And perhaps all four forces were once linked. The particles were testimony to cosmic evolution. Looking more closely is looking further back in time. Just as looking at a cell leads to DNA and the history of life. Looking more closely and there are higher binding energies. Thus accelerators, like telescopes, are time machines. Imagine a staircase where each step takes us back to a tenth of the previous. A billion years back, the universe looks different. Second step, a hundred million years since the beginning of time, everything is dark. Two more steps, everything is blinding white light. Light that will be the CBR. Further up, the temperature rises. And so on. … (The timeline of p413 summarizes this.) “Inflation” occurs way above the 40th step. And before that… the early symmetries broke. Our understanding stops at the sixtieth step, at 10^-43. Perhaps there will always be doors we cannot see beyond; or perhaps (said Wheeler) we will find something simple and inevitable. If we find a unified theory, how will we be sure of it? We could never build an accelerator to test it. Our microwave telescopes might serve instead. Shadow matter. Perhaps what we now call ‘dark matter’ is this. We might recall symmetry. Perhaps we owe our existence the broken symmetries.
Ch18, The Origin of the Universe, p349
Our speculations about the origin of the universe “told us more about ourselves than about the universe they claimed to describe: All, to some extent, were psychological projections, patterns cast outward from the mind onto the sky, like dancing shadows from a jack-o’-lantern.” 349.8.
Creation myths were about feeling reassured. Examples: gods wrestling; kicking balls; cosmic blades. Water, air, fire. Wood ashes. We can’t escape our presuppositions and desires, and so some scientists refuse to speculate on the origin of the universe. Or decide it’s impossible to determine. A first cause? God? (Sandage quote; why is there something rather than nothing?) But some scientists have tried. One idea is vacuum genesis. The idea is that “nothing” is not a vacuum, but roils with virtual particles. We can calculate rules for how these particles appear and disappear. From the energy potential of the vacuum. [[ this is what that Lawrence Krauss bk was about ]] Events can be highly unlikely but not impossible, and the creation of the universe need only occur once. 353.6. Edward Tryon first had the idea. The universe would have zero net energy. That depends on the rate of cosmic expansion. Whether it’s open or closed. In fact, it’s right on the edge, omega = 1. Perhaps the anthropic principle can be invoked; if it weren’t, we wouldn’t be here. Nobody likes that solution. Instead, the inflationary hypothesis was introduced, by Alan Guth. He was studying magnetic monopoles. They were predicted but never found. That could be explained if omega were about 1. He proposed an inflationary period of exponential growth, smoothing out the early universe. Yet this meant the most of the universe was out of causal contact with the rest. How did universal natural laws then appear? Because of the period before inflation began. Which explains why the CBR is isotropic. … this extends to the notion that black holes give birth to new universes.
The second idea is quantum genesis. Hawking and Penrose had shown that general relativity showed that the universe began in a singularity. Hawking moved on to quantum probabilities. Imaginary numbers, and ‘sum over histories’ QM. Cosmic evolution is like lines of longitude on the earth; the universe expands, then contracts; space-time is finite but unbounded. There is no ‘before’ the big bang. 364t. John Wheeler had another approach, emphasizing the quantization of space itself. … The answer we get depends on the question asked.
Ch19, Mind and Matter, p367
These results show that our species is part of the universe, not a detached observer. Matter is the same everywhere and obeys the same rules. Evolution shows there is no wall between us and the other species on earth. The idea that we are one with the universe has ancient roots. (examples) This implies that perhaps intelligent life has evolved elsewhere. A materialist perspective imagines that there it has. The Catholic Church felt threatened by this point of view; Bruno was burned, in 1600. Others speculated, including Bernard de Fontenelle in 1686. Perhaps the moon is inhabited. Search became possible by the latter half of the 20th century, via spacecraft. But flight to the stars would take too long. A better method is SETI. Project Ozma in the 70s. Senator Proxmire struck down further studies. Critics argued probabilities [the Drake equation] and the Fermi paradox. The latter can be applied to visitors too. Automated probes could replicate themselves; where are they? Maybe they’re already here. 2001. How about networks of radio communication? The time involved might be prohibitive. Perhaps a network. Diagrams, 377 and 378. We don’t need to communicate; we just want information. Such might be the ultimate purpose of intelligent life. Intelligence and technology; a cosmic mind.
Ch20, The Persistence of Memory, p381
This ‘coming of age’ has presumably been a prerequisite to cosmological maturity. Smry range of scales 382.6. Yet there is still more to know. 382b We will never understand the universe in detail. At least we’re aware of our ignorance. It is this that marks our coming of age. There will always be mysteries. Godel’s incompleteness. We will always have uncertainty. We will never know everything. Science doesn’t explain what anything “is.” And yet science works, and we can understand things about the universe. Perhaps we evolved in ways that resonate with natural law. But what does it mean to actually *understand*? Consider symmetry again. We test our ideas against the natural world. We look out and draw metaphors from the patterns we see. Science is young.
[[ The last pages are profound but complex, about the impossibility of ever perfectly knowing. There will always be uncertainty, or a next layer of reality to perceive. ]]
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Note that some big trends in physics and cosmology are either barely mentioned — string theory, dark matter — or not mentioned at all — chaos, complexity, emergence, dark energy. The book is nearly 40 years old! But it’s safe to say nothing in this book is wrong; it’s just incomplete. As science always will be.
