A Short History of Nearly Everything Summary

Author Bill Bryson begins A Short History of Nearly Everything by saying that he’s glad the reader can join him, especially because the reader—like every other living being—only exists because of a long chain of history, starting with atoms and resulting in complex life. To be alive at all is the result of an extreme amount of “biological good fortune,” since 99.99 percent of species go extinct, and the existence of all species depends on a very specific history of good timing and good luck.

Bryson also marvels at how scientists learn the things they know, and he wonders why so much science writing depicts the history of scientific discovery as abstract, dull, and technical. Bryson explains that his motivation for writing this book arose from his realization that he knows very little science himself, because he found most science textbooks boring and inaccessible during his education. His aim is to see if it’s possible to write science in a way that makes the reader marvel at the history of life on Earth and to become more curious about the task of scientific inquiry.

In Part 1, “Lost in the Cosmos,” Bryson explains how a universe like ours is formed: all of the matter in existence is compressed into a tiny, dimensionless area and then undergoes a rapid expansion (or “Big Bang”), creating all the space that exists as it spreads out. The Big Bang theory, along with “inflation theory” (the notion that the universe is expanding), were formulated in the 20th century. Bryson emphasizes how the conditions that formed our universe were extraordinary: if one small factor had been different, life as we know it would never have come about.

Bryson goes on to emphasize just how vast the universe is and how distant Earth is from other celestial bodies: Pluto, for instance, is billions of miles away, and it remains elusive to this day. There are hundreds of billions of other galaxies in addition to the hundreds of billions of stars in the Milky Way. Bryson also notes that what we perceive when we stargaze is actually an image of the past since the vastness of the cosmos means it takes light years (trillions of kilometers) for the light from stars to reach Earth. Bryson then focuses on how our solar system was formed over four billion years ago through a chance gathering of an enormous gas cloud (the sun) and tiny grains of dust colliding until they formed planets. Earth’s carbon dioxide-containing atmosphere created a “greenhouse effect” which concentrated the sun’s rays and warmed the planet. These conditions established an environment suitable for life, which began 500 million years later. Four billion years after organic compounds first emerged on Earth, life as we know it today exists.

Bryson begins Part 2, “The Size of the Earth,” with Newton’s 1688 discovery of the force of gravity and the universal laws of motion. In the 1700s, Newton’s discoveries trigger several challenging expeditions around the globe to determine Earth’s size, precise shape, mass, and location in the solar system. Bryson goes on to discuss geology, which originates in the 1700s with James Hutton. Hutton suspects that mountains are formed by land masses crashing into each other. He’s correct, but he writes so obtusely that his claims are overlooked because nobody can understand him. Nonetheless, interest in geology starts to pick up, and “stone breaking” even becomes a popular hobby among affluent 19th-century men. They dress up and venture into the countryside to dig up stones. Consequently, people start digging up dinosaur bones, although it takes a while for scientists to figure out what they are and to realize that species—like the dinosaurs—go extinct.

Bryson looks at chemistry next. He praises Mendeleyev’s elegant design for the periodic table (and Mendeleyev’s mother for hitchhiking 4,000 miles across Russia to make sure her son got an education). He also emphasizes Marie Curie’s singular achievement as the only person in history to win Nobel Prizes in Physics (for her work on radioactivity) and Chemistry (for her discovery of new elements including polonium).

In Part 3, “A New Age Dawns,” Bryson wryly notes that by 1900, scientists think they’ve figured out all there is to know about the physical world, yet their picture of reality is about to be radically altered. In 1905, Einstein formulates “relativity theory,” arguing that space and time are not static but relative to the observer. Around the same time, Planck develops “quantum theory,” arguing that light doesn’t travel in a continuous wave, but in packets called “quanta.” This means that light—perplexingly—acts like both a wave and an object. Atomic scientists like Rutherford also learn that atoms contain mostly empty space, and Bohr realizes that electrons jump around (or appear and disappear) in this space, dubbing the phenomenon “quantum leap.”

Bryson then addresses 1930s astronomy. At the time, women don’t have many opportunities beyond working as support staff who catalog stars. Nonetheless, one of these women, Henrietta Swan Leavitt (who only has access to smudged photographic images), invents “standard candles,” an “ingenious” way to measure relative distances between galaxies. Leavitt’s invention allows Hubble to calculate that the universe is comprised of billions of galaxies beyond our own, meaning it’s far vaster than anyone ever imagined. Bryson also discusses the damaging effects of pollution, focusing on atmospheric lead, CFCs, and the hole in Earth’s ozone layer, which now is unable to prevent deadly radiation from space leaking into the atmosphere.

Meanwhile, scientists discover that subatomic particles operate under completely different scientific laws than everything else in the universe. Bryson is perplexed by the highly speculative and counterintuitive theories that scientists formulate in attempts to make sense of the subatomic world. “Superstring theory,” for example, suggests that tiny particles called “quarks” oscillate in 11 dimensions (seven of which are inaccessible to humans). Bryson then shifts his focus to “continental drift” theorists who correctly claim that Earth’s land masses are in motion, that collisions between them create mountains, and that Earth is molten below its crust.

In Part 4, “Dangerous Planet,” Bryson focuses on how precarious life on Earth is. In the 1990s, scientists learn that the dinosaurs were obliterated 65 million years ago by a massive asteroid collision known as the “KT Impact.” Bryson stresses that several meteors large enough to wipe out life on Earth regularly cross Earth’s orbit, meaning that we face an ongoing threat of extinction. Bryson then addresses natural disasters. Scientists know very little about the internal seismic activity within Earth that triggers earthquakes. So far, humans have only been able to dig a few miles into Earth’s 3,950-mile-deep crust. Bryson also explains that Yellowstone National Park is an active “supervolcano” that is already overdue for its next eruption, which will destroy most of the Americas. Bryson stresses that humans should not be misguided by the relative tranquility we’ve experienced on Earth’s surface thus far, because things could change in an instant.

In Part 5, “The Stuff of Life,” Bryson explains that knowledge about deep oceans and the atmosphere at high altitudes is limited to testimonies from a handful of adventurous deep-sea divers and experimental balloon fliers until the 1950s. Since then, scientists have learned about Earth’s layered atmosphere and that ocean life is far more abundant and diverse than anyone previously assumed. Bryson worries that routinely dumping toxic waste into the oceans (like many nations do) is irreparably damaging a large part of the delicately-balanced ecosystem that keeps humans alive. Bryson also highlights that humans can’t survive for long in deep water or high altitudes—we are essentially “ground hugging beings” who can only thrive in a small sliver of Earth’s environment.

Bryson moves on to address the rise of life, dubbed the “Big Birth,” beginning with microbes that got life going about 4 million years ago that evolved into plant life, sea life, and land life—including dinosaurs and mammals. Bryson emphasizes that life is a wondrous phenomenon and that human life evolves largely out of blind luck and timely accidents. Bryson then highlights that the present-day world is full of beguiling biodiversity, and scientists only know about a small fraction of Earth’s plant and animal species—especially when it comes to underexplored environments like rainforests and deep oceans.

Turning to cellular life, Bryson explains that the discovery of cells prompts scientists to think about heredity in the 1800s. At the same time, Darwin develops his “theory of evolution.” Darwin argues that human life evolved out of simpler organisms through a process of “natural selection,” meaning that the animals best adapted to their environment survive to reproduce and pass on those traits. Darwin’s fear of religious persecution leads him to lock his notes away for almost 15 years before making his theory public in 1859. In the 1930s, scientists combine Darwin’s theory with research on heredity and formulate the “modern synthesis,” which posits that genes are responsible for inherited traits, and they are the mechanism by which life evolves.

In Part 6, “The Road to Us,” Bryson explains that scientists think ice ages are caused by a combination of Earth wobbling on its axis and cool summers that fail to melt sufficient surface ice on the planet. Paradoxically, Bryson explains, it’s unclear to scientists whether increased atmospheric carbon dioxide from human pollution will trigger a harsh ice age or harsh global warming. To Bryson, one thing is certain: we are living on a “knife edge.”

Bryson then looks into the dawn of humanity around 100,000 years ago, covering bipeds (beings that walk on two limbs), the missing link between apes and humans, and the evolution of hominids, including Neanderthals and Homo sapiens (humans). Bryson stresses that there is an astounding lack of evidence about this period in history because there are so few fossils available for analysis. Scientists know very little about the evolution of apes to humans, and they are limited at best to speculation. Bryson concludes that scientists are only at the beginning of this journey, and they face countless mysteries when it comes to learning about early hominids.

Bryson’s closes the book with a cautionary tale for the reader that focuses on the tremendous amount of extinctions caused by human activity, which Bryson describes as cruel, foolish, and careless. Bryson ends his story by urging the reader to appreciate how rare and precious life is, and how humans should take more care not to endanger our own survival or the survival of other species. For Bryson, human existence has thus far relied on luck, but in the future, it’s going to demand a lot more care and a lot less recklessness.