A Short History of Nearly Everything: Chapter 8 Summary & Analysis

By the 20th century, scientists confidently believe they’ve “pinned down most of the mysteries of the physical world.” In 1875, young German scholar Max Planck is even advised to pursue mathematics instead of physics on the basis that there is little left to discover in physics. Nonetheless, Planck studies theoretical physics, only to realize with dismay that his findings on entropy have already been discovered by an obscure retiring American scientist named James Gibbs, whose similar 1875 discovery—that thermodynamic principles also apply at the atomic level—isn’t highly publicized.

Meanwhile, in the 1880s, American scientists Albert Michelson and Edward Morley prove that “ether”—which was widely embraced by many scientists, including Newton, as an essential invisible substance that permeates everything—doesn’t exist. Newton hypothesized that the speed of light pushing through ether would change based on whether the perceiver stood toward or away from the light source. Attempting to measure this “ether drift,” Michelson and Morley are shocked to find that their experiments demonstrate light traveling at the same speed in all directions.

Planck attempts to make sense of the Michelson-Morley experiments in 1900, and he ends up formulating quantum theory. Quantum theory is based on the idea that light doesn’t travel as a continuous wave, but in chunks or packets, which Planck named “quanta.” Planck’s theory revolutionizes the field of physics. Around the same time, an anonymous clerk (with no status or university affiliation) publishes three papers in 1905 that also change the face of modern physics. His name is Albert Einstein, and the papers explain the nature of light as something that travels like both a particle and a wave. They also offer proof that atoms exist and lay out Einstein’s famous theory of relativity, which wins Einstein a 1920 Nobel Prize in Physics.

Einstein previously struggled in university—he failed his entrance examinations multiple times and eventually took up work as a bank clerk. Nonetheless, he changes the face of modern physics by formulating his infamous E=mc^2 equation, which states that mass (m) and energy (E) are two forms of the same thing, meaning that all physical objects contain latent energy and that mass can be converted into energy. It shows why radioactive objects—like uranium—radiate energy, and it explains why and how stars burn for billions of years (because even a tiny mass creates a much larger amount of energy). The equation also proves that ether doesn’t exist, and it shows that the speed of light is constant, universal, and unsurpassable.

Bryson suggests that relativity theory doesn’t sweep the public imagination the way other scientific discoveries (like dinosaur fossils) do because it’s “just so thoroughly nonintuitive.” It argues that space and time are relative to the observer. The most obvious example of this that’s applicable to humans occurs with sound: if we move away from a loudspeaker in a park, the sound seems to be quieter. The sound hasn’t changed, but our position relative to it has. A snail, however—which can’t move away nearly as fast—would not perceive the speaker’s volume changing.

Another implication of relativity is that space and time aren’t separate, but interwoven like fabric. Bryson asks the reader to imagine a mattress with a heavy iron ball on it. The mattress will sag where the ball is. If one tries to roll a lighter ball across the mattress, it won’t roll straight across, but toward the sagging part. Objects in space—like the sun—do the same thing to the fabric of spacetime: they make it sag, so lighter objects roll toward them. The effect that we perceive as gravity is actually warped spacetime, sagging with heavy objects and affecting the paths of lighter objects.

Einstein’s theory also implies that the universe isn’t static, but either contracting or expanding. Soon after Einstein figures out relativity, American scientist Vesto Slipher notices that distant stars appear red. The “red shift” effect implies that the universe isn’t static but expanding, because light moving away from humans appears red and light moving toward us appears blue. Unfortunately, Slipher doesn’t know about Einstein’s theory, so he doesn’t realize the significance of red shift. Slipher’s discovery has little impact until “a large mass of ego named Edwin Hubble” comes along.

Bryson describes Hubble as handsome, sporty, and intelligent, though prone to embellishing and exaggerating his achievements. Nonetheless, when a 30-year-old Hubble takes a position at the Mount Wilson Observatory in Los Angeles in 1919, he “swiftly and unexpectedly” becomes “the most “outstanding astronomer of the twentieth century.” Hubble wants to know how old the universe is and how big is it. Answering the question requires knowing how far away specific galaxies are (something nobody knows in the early 20th century) and how fast these galaxies moving away from us (which red shift captures).

The missing piece of information—how to measure the distance of specific galaxies—is figured out by a woman named Henrietta Swan Leavitt, who works as a clerk at the observatory surveying telescope images. She realizes that certain older stars—which she calls “Cepheids”—burn fuel in a consistent pulsing pattern when they reach a certain age (or become “red giants”). Using these “standard candles,” as she coins them, the relative distance of other stars can be calculated. As a woman, Leavitt is only permitted to look at smudged photographic images rather than into the telescopes themselves, so Bryson finds her feat remarkable—especially since her boss, William H. Pickering (who can look into telescopes whenever he wants) thinks that the moon’s craters are caused by migrating insects.

Before 1923, scientists assume that there’s just one galaxy—ours—and everything else is distant gas clouds. But when Hubble combines Leavitt’s standard candle measure and Slipher’s red shift effect, he realizes that a gas cloud in the Andromeda constellation isn’t a gas cloud at all, but an independent galaxy 100,000 light years across and 900,000 light years away. The universe is far vaster than anyone ever suspected. (Bryson notes that scientists now estimate there are 140 billion galaxies, meaning if each galaxy were the size of a pea, their total number would fill concert hall.) Then, Hubble realizes—from red shift—that all the galaxies are moving away from us, getting faster as they go.

Hubble fails to realize the significance of his finding until a Belgian theologian named George Lemaitre realizes that Hubble’s finding confirms that the universe isn’t static and eternal. It must have expanded from a single starting point, had a beginning, and might therefore one day have an end—like a firework, as Lemaitre puts it. Lemaitre effectively anticipates the concept of the Big Bang decades before Penzias and Wilson hear a hissing sound in an antenna at Bell Labs and inadvertently discover cosmic background radiation.