Brief Answers to the Big Questions

Physicist Kip Thorne authored an Introduction for the book. Thorne met Hawking in 1965 at a conference in London. Hawking was completing his PhD, and Thorne had recently finished his own. After Hawking presented his groundbreaking theory on the age of the universe, Thorne sought him out, and they began a “lifelong friendship.”

Thorne and Hawking visited Russia in 1973, where physicist Yakov Zel’dovich presented his theory that spinning black holes emit particles, which slows the holes’ spins. Hawking thought about this for months and then realized that when black holes no longer spin, they can still emit particles, and that larger holes have lower surface temperatures: “This ‘Hawking temperature’ of a black hole and its ‘Hawking radiation’ […] were truly radical—perhaps the most radical theoretical physics discovery in the second half of the twentieth century” (xvi). It significantly advanced scientists’ understanding of thermodynamics, relativity, and quantum mechanics.

In 1974, Hawking and his family spent a year at Caltech in California. His presence helped inspire Thorne to begin research on gravitational waves, ripples in space-time caused by titanic encounters between massive objects, especially black holes. (Thorne led the group that built the first gravity-wave detectors, and in 2015, they detected the first such waves, caused by the collision of two black holes.) During his Caltech visit, Hawking proposed that all information that goes into a black hole is lost when the hole evaporates. However, this would violate a law of physics, and this puzzle continues to absorb physicists. Thorne considers Hawking one of the giants of physics: “Newton gave us answers. Hawking gave us questions. And Hawking’s questions themselves keep on giving, generating breakthroughs decades later” (22).

Hawking opens with an Introduction explaining his purpose for writing the book. Early on, the author believed that the theories of physics would be completed during his lifetime. Late in life, he realized that the quest would continue for many more years. Meanwhile, problems face humanity that require “immediate action,” and Hawking hopes that future leaders rise to the challenge—not selfishly, but with awareness that Earth, seen from space, is a unified whole: “one planet, one human race” (4).

As a boy at the elite St. Albans school, Hawking was an indifferent student but bright enough that the other children called him “Einstein.” He loved long discussions about how the universe got started. He enjoyed taking things apart to see how they worked but had trouble putting them back together. Later at Oxford, he adopted the prevailing lackadaisical attitude toward studies, but when he was diagnosed with a motor neuron disease and told he had only a few years to live, he pressed forward with the projects he wanted to complete.

Hawking got his PhD at Cambridge, where he was hired as a researcher. He married Jane Wilde, his college sweetheart, with whom he raised three children. He encouraged them always to ask questions.

Applying Roger Penrose’s proposal that the universe contains “singularities,” or massive objects that collapse down to an infinitesimal point, Hawking figured out that the event horizon of a singularity—the distance from such a “black hole” within which nothing can escape—grows larger as more material falls into it. Like Penrose, he realized that relativity theory fails inside black holes and thus that these singularities might be explained via quantum theory instead. In the process, he discovered “Hawking radiation,” the particles that black holes emit as they evolve.

Hawking taught at Caltech in California for a year and then returned to England, where, in 1979, he became the Lucasian Professor of Mathematics, a position that Isaac Newton once held. During the 1980s, his illness worsened, and he contracted pneumonia and nearly died, but his wife defied the doctors—who wanted to shut off his ventilator—and took Hawking back to Cambridge. There, doctors performed a tracheostomy, which removed his ability to speak, but a US computer expert sent him a program that enabled him to select words from a screen and thus communicate more easily.

Hoping to inform a general audience on the latest discoveries about the universe, Hawking wrote and published A Brief History of Time, the great success of which surprised him. He admits that he has become famous partly for doing groundbreaking science despite a severe disability. Hawking calls on others to not only complete the theories of physics but also dedicate themselves to making Earth viable for everyone: “Let us fight for every woman and every man to have the opportunity to live healthy, secure lives, full of opportunity and love” (20).