Death by Black Hole

Astrophysicist Neil deGrasse Tyson presents a curated collection of essays originally published in Natural History magazine between 1995 and 2005. Organized into seven thematic sections, the book covers topics ranging from the limits of human perception and the physics of starlight to asteroid impacts and the relationship between science and religion.

The book opens with a prologue in which Tyson argues against the recurring claim that science is nearing completion. He cites prominent scientists who prematurely declared physics essentially finished, including physicist Albert A. Michelson in 1894 and physicist Lord Kelvin in 1901, both speaking just before revolutionary discoveries overturned classical physics. Tyson uses the analogy of chimpanzees unable to learn trigonometry to suggest that humans may face similar cognitive limits, and he catalogs major unsolved problems: the incompatibility of general relativity (which describes gravity at cosmic scales) with quantum mechanics (which governs atomic and subatomic behavior), the mysterious "dark matter" that accounts for 85 percent of the universe's gravity, and the accelerating expansion driven by an unknown force called "dark energy." He concludes that scientific knowledge accumulates across generations, with each discovery adding a rung to a ladder whose end is not in sight.

The first section examines the challenges of acquiring knowledge about the universe. In "Coming to Our Senses," Tyson argues that human senses perceive the world logarithmically, meaning large changes in stimulus produce only small changes in perception. Most major scientific discoveries came from instruments and mathematics, which is why concepts like relativity and string theory (a speculative model describing fundamental particles as tiny vibrating strings) feel counterintuitive. He traces how physicist Isaac Newton's universal law of gravitation broke the barrier between earthly and heavenly physics by showing that the same force pulling apples from trees also guides the Moon in its orbit. Spectral analysis (the technique of examining light broken into its component wavelengths to identify chemical signatures) of sunlight revealed the same chemical elements on the Sun as on Earth, and helium was first discovered in the Sun's spectrum before being identified on our planet. In "Seeing Isn't Believing," he chronicles how appearances have repeatedly misled humanity about its cosmic position: From the flat-Earth assumption through the geocentric model (which placed Earth at the center of the cosmos), each scientific revolution displaced humanity from any privileged place. Astronomer Edwin Hubble's discovery that spiral nebulae are external galaxies, and his finding that the universe is expanding, shrank the Milky Way from the entire cosmos to one galaxy among billions. Tyson also explores how both too little and too much information can obscure understanding, illustrating the point with Saturn's rings, which progressed from astronomer Galileo Galilei's observation of a seemingly triple-bodied planet to the thousands of ringlets revealed by the Cassini spacecraft.

The second section turns to the contents of the cosmos. In "Journey from the Center of the Sun," Tyson describes a photon's million-year random walk from the Sun's core, where thermonuclear fusion converts hydrogen into helium, to its surface. In "Planet Parade," he surveys the history of planetary discovery, recounting how astronomer Percival Lowell misidentified "canals" on Mars and "spokes" on Venus, the latter traced in 2002 to shadows cast by blood vessels in Lowell's own eyes. He covers asteroids and comets, explaining how Jupiter's gravity traps asteroids at Lagrangian points (stable gravitational equilibrium positions in a two-body system) and deflects comets that might otherwise strike Earth. He introduces antimatter, the mirror-image counterpart of ordinary matter, noting that when matter and antimatter meet they annihilate each other and convert entirely into energy. The fundamental mystery persists: The universe is overwhelmingly composed of ordinary matter, even though equal amounts should have been created during the big bang.

The third section examines how nature reveals its workings. Tyson surveys fundamental physical constants and, in "Speed Limits," traces the measurement of the speed of light through physicist Albert Einstein's 1905 special theory of relativity, which established that the speed of light in a vacuum is the same for all observers regardless of their motion, with the consequences that moving objects contract in length and experience time more slowly. He presents spectroscopy as the cornerstone of astrophysics: By analyzing the wavelengths of light an object emits or absorbs, scientists can determine its chemical composition, temperature, and distance. He introduces plasma, a state of matter in which atoms have been stripped of their electrons, noting it comprises more than 99.99 percent of all visible matter in the universe. The section concludes with a survey of cosmic temperatures, from the extreme heat of the big bang to the near-absolute-zero of intergalactic space.

The fourth section addresses the origins of life's chemical ingredients. Tyson explains that high-mass stars forge heavy elements through successive rounds of nuclear fusion and scatter them across the galaxy when they explode as supernovas, seeding the raw material for planets and life. Interstellar gas clouds, when cool enough, form increasingly complex molecules, from carbon monoxide and water to organic compounds such as acetylene, ammonia, formaldehyde, and polycyclic aromatic hydrocarbons. In "Goldilocks and the Three Planets," he applies the "Goldilocks" analogy to planetary habitability: Venus is too hot, Mars is too cold, and Earth is just right for liquid water. He complicates this picture by noting that tidal heating (the warming of a moon's interior caused by gravitational forces from a nearby planet) on Jupiter's moon Europa and thermophilic (heat-loving) organisms at deep-sea volcanic vents vastly broaden the habitable zone. Removing the chemically inert helium, the four most abundant elements in the universe are also the four most abundant in living organisms. Applying the Copernican principle (the idea that Earth occupies no special position), Tyson contends that declaring Earth unique among billions of planets would be unjustifiable. In "Our Radio Bubble," he notes that Earth's expanding bubble of radio signals now extends nearly 100 light-years into space, and calculates the enormous antenna sizes aliens would need just to detect a carrier signal.

The fifth section catalogs cosmic threats. Tyson explains that the solar system's long-term behavior is chaotic, limiting the ability to predict future asteroid impacts. In "Coming Attractions," he discusses the 65-million-year-old Chicxulub crater in Mexico's Yucatan Peninsula, linked to the dinosaurs' extinction, and notes the near-term threat of asteroid Apophis, which in 2029 will pass closer to Earth than communication satellites. Three longer-term scenarios follow: the Sun's expansion into a red giant (an enormously swollen, cooler star in a late stage of stellar evolution) engulfing Earth in about 5 billion years, a collision between the Milky Way and Andromeda galaxies in about 7 billion years, and the universe's eventual heat death as all stars burn out. He explains how supermassive black holes power quasars, among the most luminous objects in the universe, by shredding and superheating infalling matter, and in the title essay "Death by Black Hole," provides a vivid account of "spaghettification," the process by which tidal forces near a black hole would stretch a human body into a stream of atoms.

The sixth section addresses the interface between science and culture. In "Things People Say," Tyson catalogs commonly repeated falsehoods, such as the belief that the North Star is the brightest star (it does not rank in the top 40) and that total solar eclipses are rare (they occur about every two years). He examines widespread innumeracy, surveys national scientific legacies from Islamic civilization's contributions (algebra, algorithms, and Arabic numerals) through American dominance in 20th-century astrophysics, and addresses light pollution as a threat to astronomical observation. In "Hollywood Nights," he humorously catalogs scientific errors in Hollywood films, including an incorrect star field in Titanic that director James Cameron eventually corrected after Tyson pointed out the mistake.

The final section examines the relationship between science and religion. Tyson walks through the first moments of the universe, describing how a slight asymmetry of roughly one billion and one matter particles to every billion antimatter particles ensured that matter survived mutual annihilation. Within 380,000 years, the universe cooled enough for electrons to combine with atomic nuclei, releasing the cosmic microwave background radiation (the faint, omnipresent glow of microwaves left over from the big bang) detectable today. In "Holy Wars," he argues that no successful scientific prediction has ever been derived from a religious document, and recounts Galileo's trial for heresy and the execution of Giordano Bruno, an Italian monk and philosopher burned at the stake for heretical views including the suggestion that the universe might contain other inhabited worlds. He notes that while about 40 percent of American scientists identify as religious, successful researchers do not derive their science from religious beliefs. In "The Perimeter of Ignorance," Tyson traces a recurring pattern he calls "the perimeter of ignorance": Scientists from the ancient astronomer Ptolemy through Newton and the physicist Christiaan Huygens invoked God at the boundaries of their understanding, only for subsequent researchers to fill those gaps with natural explanations. He critiques the modern "intelligent design" movement as a philosophy that halts inquiry, cataloging examples of poor biological "design" (such as the shared pathway for breathing and eating that creates a choking hazard) and arguing that allowing intelligent design into science classrooms would stifle the curiosity needed for future breakthroughs.