Zoom: From Atoms and Galaxies to Blizzards and Bees: How Everything Moves (36 page)

9. In particular, the direction in which a planet’s lopsided elliptical orbit angles away from the sun is not fixed. The orbit itself twirls around like a squashed Hula-hoop, changing its orientation in space. Even the moon’s oval orbit keeps changing the direction in which its longest dimension, which performs a complete rotation around Earth every 8.86 years, is aimed. So it’s not just the moon that circles us; its elliptical orbit whirls around us as well, at a rate 118 times slower. The planet Mercury’s squashed orbit does the same, but twice as quickly as can be explained by Newtonian physics.

10. Einstein even messed up his own calculations. He originally came up with a very wrong figure for the amount of spacetime distortion at the surface of the sun. That would have been disastrous for him, because the best test of his theory was to measure a star’s position at the solar edge. Distant starlight skims right over the sun’s limb, or edge, en route to our eyes, traversing the place of maximum spacetime bending. It should, according to Einstein, make the light take a longer path and cause the star to appear in an unexpected position—a deflection that, he said, should be readily measurable.

When can we see and measure a background star adjacent to the blinding solar edge? During a total eclipse! Thanks to World War I, a 1915 eclipse that could have tested the relativity theory was not suitable for viewing—an expedition to see it would have been unsafe. But by the time a total eclipse approached in May of 1919, an event in which the darkened sun would be fortuitously positioned amid the many stars of the Hyades cluster in Taurus, Einstein had corrected his math and offered a new figure for a star’s expected deflection from its catalog position. Famed British astronomer Arthur Eddington, an Einstein booster, led an expedition that did indeed measure exactly the predicted results, which made Einstein a household name overnight. But skeptics howled. Eddington had used a tiny telescope with a four-inch mirror. The observations were performed in turbulent daytime air; the star images were blurry and dancing. The required accuracy was an arc second—the apparent size of a twenty-five-cent coin seen at a distance of three miles. Had Eddington really confirmed Einstein, or, rather, did he merely see what he wanted to see?

The famous 1919 results remain controversial to this day. No matter; later observations confirmed relativity. Spacetime was real. The motion of celestial objects was attributed to their journey across curved space.

11. Unlike the three other fundamental forces that describe relations between physical systems, gravity remains remains mysterious. The other three—electromagnetism (which manifests itself as magnetism and electric fields and such), weak nuclear force, and strong nuclear force, which operate only within the tiny regions in atoms—have even been theoretically tied together. But gravity eludes all attempts to weave it into any larger picture, to connect it with the others.

1. Actually we must distinguish animal limbs from a weight or bob at the end of a wire, a true pendulum, to which the wire doesn’t contribute very much to the total mass of the device. If instead a heavy, rigid rod is used in a pendulum—or, in this case, the rigid massive bone of the femur—then the oscillation rate matches that of a true pendulum (one on which the bob is nearly the entire mass and what holds it is a negligible mass, like a wire) that’s two-thirds the length. So on a human, whose foot is just a smallish mass compared with the entire weight of the leg, that two-thirds business comes closest to providing us with the observed period. To use real numbers, a weight on a wire that’s thirty-nine inches long will have a round-trip period of two seconds. But a human foot acting as a bob, at the end of a thirty-nine-inch bone, will swing as if it’s on a pendulum just twenty inches long and complete the back-and-forth in about 1.5 seconds.

2. The first national highway using the Scotsman John Loudon McAdam’s method was an eighty-foot-wide triumph that headed west from Cumberland, Maryland, which eventually became part of US Route 40. But McAdam’s real contribution was in creating more cost-effective ways of building these roads—and of popularizing them. The three-layers-of-stones method, with the finest compacted at the top, had been designed decades earlier by the Frenchman Pierre-Marie-Jérôme Trésaguet. Perhaps it was simply easier on the tongue to call them macadam roads.

3. Want to know how fast you’re likely to travel on your next trip? Here are more airliner speeds. The Boeing 777 goes 639 miles per hour, the 767 does 609 miles per hour, and a slew of commercial jets—including the Airbus A320, A310, and the omnipresent Boeing 737-800—fly at 594 miles per hour. If you’re nostalgic for the old stagecoach experience, then travel on the older but still commonplace Boeing 737-300/400/500 models. They lope along at just 563 miles per hour.

4. What’s the fastest any of our body parts can ever go naturally? It’s a close call. There are only two contenders. The best pitchers can hurl a fastball at 102 miles per hour, which means that a pitcher’s own fingertips are traveling through the air that quickly at the moment of release. This would match the fastest-ever sneeze on record, creating a tie for the “swiftest speed a person can achieve” award. (The absolute fastest pitch on record was thrown in 2010, when the twenty-two-year-old Cincinnati Reds left-handed reliever Aroldis Chapman made history by hurling the fastest pitch ever measured by radar in a major-league game, at 105 miles per hour.) Maybe there ought to be separate trophies for voluntary and reflexive categories.

1. The aquatic ape hypothesis (AAH) states that many otherwise puzzling features of Homo sapiens can be explained aquatically. The hypothesis was first proposed in 1942 by German pathologist Max Westenhöfer and, independently, in 1960 by British marine biologist Alister Hardy. It was tirelessly publicized by the Welsh author Elaine Morgan in books such as The Aquatic Ape and The Descent of the Child.

We didn’t start out on the savanna as just a smarter variety of ape, goes this line of reasoning. Instead, our ancestors were stranded (probably in East Africa) during a period of rising sea levels. Or, alternatively, we found ourselves with too much competition on land and took to finding our fortunes in lakes and inland waterways. Perhaps one large colony of our ancestors became marooned on an island at a time of rising sea levels and had to learn to live on the beach and make its fortune from the ocean.

Our ancestors started using tools because they needed to pry open clams and such. We spent more time in the sea and soon lost our furry coats, because hairlessness is an advantage in water. Perhaps the hair on our heads remained so that our young could have something to hold on to when we swam. Our noses grew far longer than that of chimps so we could breathe more easily when trying to keep our heads up. Our fat became attached below the skin, just like that of dolphins and whales, rather than forming as a separate layer, like that of all the other apes and land mammals.

When surprised or terrified, we gasp. Why? Apes never gasp. It only makes sense if it’s the vestigial legacy of taking a sudden breath in order to dive.

The AAH also explains why we are so obsessed with water. Other apes will cross water only when they have to, or if there’s food on an opposite bank. They don’t love it. We do: we vacation at lakesides and by the sea, and a newborn baby will instinctively act appropriately and not drown—at least not right away—if thrown into water. (Don’t try this!) While the aquatic ape hypothesis is largely ignored or belittled by paleoanthropologists, I wouldn’t be surprised if schoolchildren a century hence are taught that explanation of our origins.

2. It’s no accident that liquid water exists within a 180-degree range, from thirty-two degrees to 212 degrees. When Daniel Fahrenheit created his scale, he wanted ice and steam, which he regarded as opposite states of matter, to be represented by numbers that were opposites of each other. In a circle or compass, the opposite direction, an “about-face,” is 180 degrees from where you started. Moreover, the geographic poles lie 180 degrees of latitude apart. The same goes for longitude: places farthest east or west from the zero point, at Greenwich, England, have longitudes of 180 degrees. So Fahrenheit made his scale’s one-degree gradations of the necessary size so that 180 of them would mark the progression from freezing to boiling. As for why he chose such an odd number to be water’s freezing point, it was because his zero was the coldest liquid he could produce—a slurry of near-frozen salt water. Starting there, he found that plain water freezes thirty-two degrees higher up.

3. Here is another top Jeopardy!-level fact: the moon is a place where water could freeze and boil simultaneously.

4. Accidents no longer rank among the top three causes of death, except among young people, but there is a major gender gap in accidental death rates. Only 3.5 percent of women die from an unintentional injury, but for men the rate is 6.5 percent. I doubt this will surprise anyone.

5. I just said “three-foot” tidal bulge located roughly beneath the moon, but coastal areas get an average five-foot tidal range, thanks to the amplification effects of the shallower seabed there. But out in the open sea it’s three feet.

6. Where I live, one hundred miles up the Hudson River from New York City, the ocean tides manage to march all the way at full force. Once high tide hits Manhattan it progresses upriver at seventeen miles per hour and takes six hours to reach us, which means when it is high tide up here it is exactly the next low tide down in the big city. While the swell of the tide moves at seventeen miles per hour, the water itself does not. Anyone watching floating debris on Hudson River tides, as in that tidal bore, will see it progress only slowly northward with the incoming tide and will then later observe it flowing south. It may repeat the zigzag process several times before it finally clears one’s location for keeps. This is why it would take someone in an inner tube 126 days to float from my region to lower Manhattan—about four months to go that hundred miles. Few commuters choose this inexpensive travel option.

7. Compared to the historically grievous Alexandria tsunami, perhaps ten times more people died on the day after Christmas in 2004 as a result of the intense Indonesian tsunami, which was caused by a quake that released the power of 23,000 Hiroshima-type atomic bombs. But how long will it be memorialized? Do we annually think about those 228,000 people even now, a few years later, after they succumbed to the sixth-worst natural disaster in human history? This surely speaks of the big-heartedness of the Alexandrians, who kept alive the memory of the victims of the 365 CE cataclysm for more than two hundred years.

1. Researchers finally realized that most of the radiation from radium took the form of alpha particles. These are heavy clumps of two protons and two neutrons, slow-moving enough that they cannot even penetrate skin. The real problem arises if radium is inhaled or swallowed. Then it is absorbed by bones, where its alpha emissions steadily bombard and destroy the marrow.

2. In 1938, after winning the Nobel Prize, Hess relocated to the United States with his Jewish wife to avoid Nazi persecution. He immediately became a Fordham University physics professor and lived in an apartment in Mount Vernon, New York, until his death in 1964.

3. Physicists call ordinary light electromagnetic radiation, yet it’s not the least bit harmful; we’re not zapped with danger whenever we flip a wall switch. Long-wave light, like the kind we see, and the infrared rays we can feel on our skin can’t damage atoms. Visible light, radio waves, Wi-Fi, even microwaves cannot abuse genes and cause cancer. Living next to a cell phone tower means that invisible microwaves are flying through you at light speed and can make entire atoms in your body jiggle. This can slightly heat up tissue, but it can’t break those atoms or make tumors form. (It still might not be good for you!) By contrast, gamma rays’ and X-rays’ short waves do break apart atoms. This is “ionizing radiation,” the bad kind that can sabotage genes. Heavy, fast-moving subatomic particles, such as neutrons and protons, can also destroy atoms, so they’re often called radiation even though they’re particles and not energy waves. The distinction is blurry anyway, since all matter has a wavelike aspect.

4. One trustworthy reference source says that a one-light-year-thick lead wall is excessive. That you could stop the average neutrino with a mere body of water that stretched from the sun to Saturn. That’s 6,400 times narrower than a light-year and would be a lot cheaper to obtain, even if you couldn’t order it on Amazon. Either way, catching neutrinos isn’t something you do casually.

5. Life’s general rule is that moving entities are often endearing as long as they can’t attack us and as long as there’s not a lot of them. Two birds chirping outside the window is a joy. A flock of two thousand birds would be something out of a Hitchcock flick. One ladybug on the windowsill is pretty. The presence of a thousand requires remedial action. Squirrels, chipmunks, ants, even intestinal flora: we want our in-motion companions to present themselves in limited quantities. Yet neutrinos and probably dark matter constantly pervade us in unimaginable numbers, but they don’t have “bad PR” because they’re not just invisible: they also do not meddle.

1. The hummingbird’s dual nature—now you see it, now you don’t—combined with its exquisite colors made it an obsession for some early civilizations. The Aztec god Huitzilopochtli is usually depicted as a hummingbird. And the outline of one appears in the famous Nazca lines of Peru.

2. By playing their mythology card, the Greeks created imaginary ways creatures could move. Having the head of a human and body of a horse, for example, yielded a composite that somehow offered only the advantages of each. My favorite such hybrid creature was envisioned by Woody Allen. It had the head of a lion and the body of a lion—a different lion.