The Universe as It Really Is

Earth, Space, Matter, and Time

Thomas R. Scott, James Powell

• Publisher: Columbia University Press
• Year: 2018
• ISBN:
  9780231545761
• Topic: Philosophy
• Subtopic: Philosophy & Ethics in Science

The universe that science reveals to us can seem far outside the comfort zone of the human mind. Subjects near and far open up dizzying vistas, from the infinitesimal to the colossal. Humanity, the unlikely product of uncountable coincidences on unimaginable scales, inhabits a tumultuous universe that extends from our immediate environs to the most distant galaxies and beyond. But when the mind balks at the vertiginous complexity of the universe, science unveils the elegance amid the chaos.

In this book, Thomas R. Scott ventures into the known and the unknown to explain our universe and the laws that govern it. The Universe as It Really Is begins with physics and the building blocks of the universe—time, gravity, light, and elementary particles—and chemistry's ability to explain the interactions among them. Scott, with the assistance of James Lawrence Powell, next tours the earth and atmospheric sciences to explain the forces that shape our planet and then takes off for the stars to describe our place in the cosmos. He provides vivid introductions to our collective scientific inheritance, narrating discoveries such as the shape of the atom and the nature of the nucleus or how we use GPS to measure time and what that has to do with relativity. A clear demonstration of the power of scientific reasoning to bring the incomprehensible within our grasp, The Universe as It Really Is gives an engrossing account of just how much we do understand about the world around us.

IT’S ELEMENTARY

Nothing exists except atoms and empty space; everything else is opinion.

—Democritus

For most of human history, knowledge has been passed from one generation to the next through storytelling in small groups. Our ancestors told tales of personal experiences, of events affecting their daily lives, or they recited those from earlier generations. Timing ranged from the millisecond accuracy needed to fling a well-aimed rock to the annual rhythms of migration, or of planting and harvesting. Distances went from the millimeter accuracy of finger movements to the kilometers over which our ancestors could communicate through courier, voice, smoke, and drum. In each case, whereas the range from shortest to longest time and from shortest to longest distance was a factor of millions to a few billion, it still covers only the tiny portion of the physical spectrum that includes human activity. We’re too slow to watch light move but not slow enough to watch tectonics or evolution unfold; too small to see Earth as a globe but not small enough to see our cells at work. When their knowledge fell short of explaining natural events—the rising Sun, volcanic eruptions, thunder, disease—these storytellers invoked the supernatural, personified either by a cast of gods and goddesses interacting with enough intrigue to satisfy Richard Wagner or, more recently, by an omnipotent God, similarly imbued with human emotions of rage and love.

Only recently have we developed the technology to extend our experience of both time and space by a factor of billions and in each direction, from attoseconds to the age of the cosmos and from the Planck constant¹ to light-years of distance.

Atoms are inconceivably small, numerous, and enduring: unless violated by unearthly energies, an atom is thought to last 10³⁵ years.² How many are there? We can estimate the number by thinking in stages: there are about 100 million million (10¹⁴) atoms in one of your cells; coincidentally, you are made of about 100 million million (10¹⁴) cells. It would take as many of “you” to fill the Sun as there are atoms filling you (10²⁸). There are at least 100 billion (10¹¹) stars in the Milky Way and 100 billion (10¹¹) Milky Ways in the observable universe. If we multiply it out, we find that all the matter we can see contains about 10⁷⁸ atoms. Most of them are hydrogen or helium. You and I, at 67 percent hydrogen, are no exception.³

Somewhere in the process of convening your personal 10²⁸ atoms, the inanimate sprang to life, serving your purposes for several decades and then joining the oceans and hills, later to become part of your great-great-granddaughter and both the virus that will threaten her life and the vaccine that will save it. And if you want to consider communion a literal event rather than settling for the metaphorical wafers and wine, you will consume a few billion atoms today that once briefly stopped by to make Jesus.⁴ Atoms may not be all that matter—we still have to figure out dark matter and energy—but they are all of earthly matter. We’ll start with the story of their discovery, their character, their own components, and how they join to build us.

THE RISE OF ATOMS

In the village of Abdera in northern Greece, Democritus (ca. 460–ca. 370 BCE) was born into a family of such wealth and prominence that Xerxes sought them out to entertain his soldiers on their path back to Persia. In gratitude for their hospitality, the Persian monarch left magi⁵ with the family to instruct Democritus on theology and astronomy. The wonder of exotic lands and concepts captured Democritus’s youthful imagination, and upon receiving an extravagant inheritance,⁶ he determined to explore his known world. He traveled to Africa and settled for five years, gaining insight from Egyptian and Ethiopian mathematicians. He explored Asia, consorting with Mesopotamian magi and Indian philosophers who kindled in him the concept of a-kShanDA-pakSha—that which is not divisible—which was to shape his concept of matter.

Years of travel both exhausted Democritus’s inheritance and slaked his curiosity. He returned to Greece, void of funds but full of insight, to make his way offering visions of exotic lands through public lectures. As his recognition spread, Democritus learned of Leucippus, who was developing a theory that all matter was composed of invisibly tiny units of various types. The resonance with Indian philosophy was seductive to the youth, and the two became mentor and student. Democritus was a cheerful, playful scholar, known in the classical world as the “Laughing Philosopher,” a moniker that endeared him to some and led to his dismissal as a lightweight by others, including his younger contemporary, Plato.

Democritus adopted Leucippus’s theory and embellished it. He contemplated the result of dividing an object into successively smaller parts and reasoned that this could not go on indefinitely. There had to be some point, well below the limit of human vision, where the particles to which an object had been reduced were themselves indivisible. He called these hypothetical units atomos, meaning “not able (a) to be cut (tomos).”

The atomic theory that arose from these ruminations held that the objects that fill our Earth and the heavens are not single, integrated items with inherent properties but rather structures built of minuscule elements, or atoms. These elements are indestructible, infinite in number, and infinite in type. The atoms of a particular type are all identical in size and shape, yet have the idiosyncratic features that give them their character. Iron atoms must be solid, with hooks that lock them firmly together in a lattice; water atoms are slippery and smooth; salt atoms have points, imparting their sharp taste; air atoms spin and whirl. Between atoms is nothingness, a tiny void of empty space.

How did Leucippus and Democritus arrive at their prescient theory? Bertrand Russell thought they just got lucky, as there was no empirical evidence to support the existence of atoms. But Lucretius—in his poetic defense of atomism, the six-volume De Rerum Natura (On the nature of things)—noted that Democritus wrote about the tendency of elements to mix and then separate: water and dust mix to make mud, but then dry back to dust; wood rots, but its seeds produce new wood in its parent’s image. There must be some component in the core of objects, Democritus reasoned, that is unchanged by circumstance, that always carries the same signature, even as it combines with other components to build complex structures like the human body. The classical theory of atoms may be closer to our modern concept of molecules, but the path was true.

Aristotle (384–322 BCE) rejected Democritus’s theory because it based matter on invisible units. Aristotle had brought the heavenly visions of his mentor, Plato, down to Earth and valued only that which could be verified through our senses (empiricism). Atomos could not be perceived or measured and were thus to be dismissed in favor of the four perceptible essences—earth, air, water, and fire—plus a fifth essence (a quintessence) of the heavens we could not experience. Aristotle’s notion was easier to visualize and accept. The essence theory of matter dominated popular thought for centuries and remains influential among astrologers. The next two millennia comprised a period that historian Joshua Gregory called “the exile of the atom.”

This exile ended with the Renaissance and the arrival of scientific giants Francis Bacon, Galileo Galilei, and René Descartes. They all advocated for a revised version of atomic theory, which labored under the burdensome name of corpuscularianism. Invisibly small particles still combined to form our familiar world, they wrote, but these particles, called corpuscles, were themselves divisible, rather like the modern concept of chemical compounds.

Corpuscles, however, were still in the realm of philosophy. By the beginning of the nineteenth century, knowledge of the elements had advanced to the point where thought experiments could be tested in a laboratory. Foremost among the empiricists was Englishman John Dalton (1766–1844). Born to a Quaker family in Cumberland, at age 15 Dalton joined his older brother in running a Quaker school. When he came of university age, he sought to train in law or medicine, but “dissenters”—those who had broken with the Church of England, as the Quakers had—were excluded from British academics. The rejected Dalton repaired to Manchester to take extensive, if informal, instruction from a blind philosopher, John Gough, and then to accept a teaching appointment at Manchester’s New College, a dissenting academy. When the college fell on hard times in 1800, Dalton resigned and was able to maintain a modest income through private tutoring while exploring the science of atomism.

Though Dalton was relegated to the margins of the scientific establishment, his vigorous pursuit of the fundamentals of matter never flagged. He measured his surroundings relentlessly, keeping a meticulous diary of daily observations for 57 years. His neighbors in Manchester came to set their clocks by his appearance at his window to take the morning temperature. He carefully recorded his visual perceptions through his own affliction with red-green color blindness—still called Daltonism by many—falsely attributing it to the filtering of longer wavelengths by his blue eyes.

Dalton’s tool kit was limited to the common instruments of the day: thermometers, pressure gauges, burners, flasks, and such. But his topics were enhanced by new knowledge about gases. Joseph Priestley had recently discovered oxygen. Antoine Lavoisier had delayed his appointment with the guillotine just long enough to show that both oxygen and hydrogen were gaseous elements.⁷ Dalton had the ingredients he needed to begin composing a natural world from atoms. Aristotle’s essences, whose stock had already been sagging under the weight of the scientific discoveries of the Enlightenment, were demonstrably not fundamental components of our existence but rather could be separated into the same elements in the same proportions. Water always yielded oxygen and hydrogen in a 1:2 ratio. Dalton expanded his analysis of liquids and gases to six elements: hydrogen, carbon, nitrogen, oxygen, sulfur, and phosphorus. From their combinations, he developed his law of multiple proportions, which defined atoms and their interactions. His tenets were that all objects are made of atoms that cannot be created, destroyed, or changed; that atoms of a given element are identical; that atoms of different elements combine in particular ratios to form compounds; and that chemical reactions occur when atoms combine, separate, or rearrange. It was 1808. We had matter; we had chemistry. Had Democritus only lived long enough, the Laughing Philosopher would have had the last one.

Dalton gained recognition and honors late in life, but he led a private, unassuming existence. Not so his devotee, Swedish chemist Jöns Jacob Berzelius (1779–1848). The Swede was trained as a physician but practiced experimental research more than medicine. His empirical approach and logical insights soon brought him to the attention of the scientific community, which had been marginalized as Sweden embraced romanticism in the late eighteenth century. He ushered in a golden age of Swedish science. At age 28, he was appointed professor of chemistry and pharmacy at the prestigious Karolinska Institute. He championed Dalton’s atomic theory, discovered six new elements, and demonstrated that inorganic compounds are made of atoms combined in whole numbers. Berzelius was the first to distinguish between inorganic and organic molecules, identifying what came to be known as proteins.⁸ He recognized that some atoms carried an electrical charge and introduced the term ion to describe them. There are two types of electrical charges, denoted positive and negative. Objects with like charges repel each other, whereas objects with opposite charges attract each other. He further enriched the chemical lexicon with the terms catalysis, polymer, and isomer.⁹ Most fundamentally, he gave us the system of chemical symbols that we use today, based on one or two letters from the Latin name for each element: Na (natrium) for sodium; K (kalium) for potassium, Ag (argentum) for silver, Au (aurum) for gold, and so on.

Berzelius became a personal force in resurrecting Swedish science. He was elected to the Royal Swedish Academy of Sciences at age 38 and served as its secretary for his remaining 30 years. He maintained a robust correspondence with an international corps of scientists who were creating the new discipline of chemistry in the early nineteenth century. His fame was widespread, and he enjoyed the recognition of a grateful nation. In 1818, he was ennobled by Charles XIV John, king of Sweden and Norway (hence the two names). Statues were raised to Berzelius, a school was named for him, and his likeness appeared on Swedish stamps. This “Father of Swedish Chemistry” is still honored each August 20, Berzelius Day, in Sweden.

Although atomic theory was now firmly rooted, no one quite knew what an atom was. It was assumed to be a solid lump of its element, true to the name that Democritus had coined for that which could not be cut. It was to fall to the experiments of Britain’s J. J. Thomson (1856–1940) and New Zealand’s Ernest Rutherford (1871–1937), working at Cambridge University’s famed Cavendish Laboratory,¹⁰ to show otherwise.

In 1897, Thomson placed atoms of various elements on a negatively charged electrode (cathode) and found that radiation streamed away, driven by the electric charge. The fleeing particles were negatively charged and weighed nearly nothing. Moreover, that puny weight was the same regardless of which element released it, so these strange creatures were a part of every type of atom. They were electrons, and their discovery flummoxed physicists. Tiny particles with a powerful negative charge in an electrically neutral atom? Whatever else was in there had to be equally positive.

Thomson assumed that electrons were baked into a larger, heavier structure that achieved neutrality through a diffused positive charge. His vision became known as the plum pudding model, with a positively charged dough impregnated with negatively charged electron plums.

Rutherford, then at Manchester University, put this to the test. He aimed alpha particles,¹¹ each with a mass 8,000 times ...

Table of contents

• Cover 
• Title Page
• Copyright
• Dedication
• Contents 
• List of Illustrations
• Preface
• About the Author and This work
• Introduction
• 1. It’s Elementary
• 2. Getting Together: Atoms to Molecules
• 3. Gravity
• 4. Time
• 5. Light
• 6. Earth: A Biography
• 7. Earth: A Physical Exam
• 8. Atmosphere and Weather
• 9. Oceans
• 10. The Sun
• 11. The Solar System
• 12. The Milky Way
• 13. The Cosmos
• Notes
• Bibliography
• Index