Zoom: From Atoms and Galaxies to Blizzards and Bees: How Everything Moves (22 page)

This invisible stuff is part of our everyday lives. It’s not entirely harmless. Yet there’s nothing we can do to get rid of it unless we ask a real-estate agent to find us a nice two-bedroom deep in a mine.

This story begins in 1800. That’s when William Herschel discovered a form of light nobody can see. Invisible light? If anything ever came from left field, it was this. It fit nowhere in mankind’s evolving models of the cosmos. The discovery would have surely been doubted and ridiculed except that Herschel was then the world’s most respected scientist, famous for having found the first-ever new planet, Uranus, nineteen years earlier. (Nobody had seen that one coming, either.)

Since light can be regarded as a stream of particles, we can truly say that countless unseen bullets continually zoom around us. This first-known invisible form of light doesn’t quite go unnoticed, though. Our skin detects Herschel’s “calorific rays” (eventually called infrared radiation) as the sensation of heat. Nearly half the sun’s emissions are infrared. So when we look around us, an equal mix of visible and invisible particles are bouncing off the rocks and rabbits.

You may imagine that heat moves slowly. It takes a while to warm up a frying pan. But infrared rays, which create heat on our skin by making its molecules move faster, are light-speed swift. You experience this when gathered around a campfire on a chilly night. If a big person steps in front of you, you instantly feel the effect because that person blocks the invisible infrared rays from hitting you. He’s creating infrared shadows.

A year after Herschel’s discovery, in 1801, the sad-sack German Johann Ritter discovered ultraviolet light but failed to publicize it sufficiently. He had a tendency to ramble on about extraneous matters, such as his belief in ghosts, so he ended up ignored and impoverished. He wasn’t credited with his discovery until after his death—the glory, appropriately, awarded to his disembodied spirit.

Things took an even more disquieting turn near the end of that century. On November 8, 1895, another German—Wilhelm Röntgen—discovered X-rays. As we all know, these waves or particles do not stop when they reach the skin. They can fully penetrate our bodies, although many are absorbed by dense material such as bones and teeth. When, two weeks after his discovery, Röntgen took the very first X-ray pictures, showing the hand of his wife, Anna Bertha, she stared with horror at the image of her skeleton and exclaimed, “I am seeing my death!” (Given the then-unknown deadly potential of shortwave radiation such as X-rays, which ultimately took the life of Marie Curie—the first person to win two separate Nobel Prizes—and many thousands more in places such as Chernobyl and Hiroshima, Anna Bertha’s comment may seem eerily prescient.)

In 1896, the Dutch physicist Hendrik Lorentz posited the existence of a totally different invisible speedster: the first-ever subatomic particle, the electron, even tinier than the theoretical atoms suggested by Democritus 2,300 years earlier. Lorentz had plunged deeper than any other physicist before him and brilliantly figured out the origin of all light! He said that light comes into existence solely because of the motions of a tiny, negatively charged object. When the electron was duly discovered soon thereafter, Lorentz’s prescience earned him the 1902 Nobel Prize in Physics.

This was a productive time for finding invisible entities. The pace didn’t let up. Also in 1896, French physicist Henri Becquerel got swept up in the global excitement of Röntgen’s X-ray discovery of the previous year. Becquerel’s interest was in materials that glow, so he thought phosphorescent substances such as uranium salts might emit X-rays after basking in sunlight. By May of that year, however, he correctly realized that the uranium emitted some new and unknown form of “radiation,” as it was starting to be called. Seven years later, in 1903, Becquerel won the Nobel Prize in Physics, sharing it with Pierre and Marie Curie, who had taken Becquerel’s ideas and run with them.

The newly married couple was fascinated by substances that emitted what Marie called uranium rays. After years of watching these strange rocks produce smatterings of light on photographic film, the Curies realized that the most intense radiation flew out from two brand-new elements. She named the first polonium, after her native land, Poland, and the second radium, for the mere act of radiating. This latter element was her baby, her darling; she called it “my beautiful radium,” for she possessed no inkling that it would someday kill her and many others with its sizzling emissions. It was three thousand times more radioactive than uranium.

So now, quite suddenly, nineteenth-century scientists had revealed a motley crew of five invisible entities flying around or through us.

Ultraviolet photons can burn us at the beach and set the stage for skin cancer, but they are also beneficial, even vital; the body creates vitamin D when struck by them.

X-rays are scarcely present naturally here on Earth.

Infrared rays are commonplace but harmless.

So are electrons, streams of which were used for decades in the old-style TV picture tubes to conjure Mister Rogers and Lucy Ricardo.

But Becquerel’s and the Curies’ uranium-and radium-based “radiation” would prove far more dangerous, even if radium was initially believed to be a healthful substance, a tonic. (To this end, it was marketed as an elixir, mixed with sparkling spa waters and touted as a rejuvenating agent. Millions of bottles were sold and drunk. Later came radium watches with their glowing numbers and dials, painted in factories mostly by young women who suffered horrible early deaths before the peril was recognized.)1

The spooky quest for unseen phantoms soon got even spookier. In 1909 Theodor Wulf created an early equivalent of a Geiger counter—an instrument called an electroscope, which revealed whether atoms inside a sealed container were being broken apart. It showed higher levels of radiation at the top of the Eiffel Tower than at its base. Because this made no sense—the device was then farther from the ground’s uranium and radium sources—his paper was ignored. But on August 7, 1912, Austrian physicist Victor Hess personally took improved versions of the electroscope up in a hydrogen balloon to 17,400 feet, and it revealed radiation levels twice as intense as those on the ground. He correctly attributed this to a radiation source arriving from outer space.

Hess soon eliminated the sun as the cause: he flew a balloon during a solar eclipse, when the moon blocked nearly all the sun’s incoming energy. He also, perilously, conducted some flights at night. The conclusion was amazing, if disquieting. He announced, “A radiation of very great penetrating power enters our atmosphere from above.” For this discovery—which still has ominous ongoing implications for pilots, in addition to posing a serious hazard to any future human colonies on other worlds—Hess won the 1936 Nobel Prize in Physics.2

By amazing coincidence, precisely one century to the day after Hess’s balloon flight, on August 7, 2012, the newly landed Mars rover Curiosity began measuring this radiation on another planet for the first time.

Physicists initially believed these invisible outer-space invaders were some kind of wave, an electromagnetic phenomenon, which is why they were—and mostly still are—called cosmic rays. Each of those two words tingles with sci-fi creepiness and vaguely implies a bizarre peril from beyond the stars, thus awarding cosmic rays the scariest and perhaps coolest name of all the tiny, streaking, high-speed entities.

But they aren’t rays at all. Meaning they’re not a form of light. Their incoming paths are bent by our planet’s magnetic field, and light never changes direction in response to magnetism. Cosmic rays simply couldn’t be another electromagnetic phenomenon, as X-rays are. Before the start of World War II, everyone realized they must be electrically charged particles, like the ones that stream (as we finally recognize) from uranium and radium.

The truth, the denouement, is both powerful and anticlimactic. Cosmic rays are mostly protons. Ordinary, plain-vanilla protons, the nucleus of hydrogen, the positively charged particle found in every atom’s heart. They’re violently ejected in supernova explosions and wander the universe like homeless high-speed swashbucklers.

But why is 90 percent of this incoming substance protons? Why does it include just a negligible sprinkling of electrons (1 percent)? There are just as many electrons as protons in the universe. Why are electrons so underrepresented?

Befitting their spooky name, cosmic rays are thus puzzling even today, thanks to their illogically proton-heavy composition and the fact that a small percentage of them scream into our atmosphere at bewilderingly high, near-speed-of-light velocities. Cosmic rays even include a bit of antimatter.

Protons weigh 1,836 times more than electrons, so they pack a wallop when they hit anything. Fortunately our atmosphere and our magnetic field block most of them. While you and I do get penetrated regularly, they’re a medical problem mostly for astronauts, which is why the twenty-seven Apollo adventurers all saw spurious bright streaks cross their visual fields every minute, as protons ripped through their brains.

Moreover, as in a game of billiards, protons typically strike air atoms thirty-five miles up and knock loose a cascading shower of smaller stuff. One of these is the muon, which decays rapidly but not before it, too, penetrates our poor pincushion bodies.

At least two hundred muons per second zip through each of us. They weigh 208 times more than electrons, so they’re not exactly harmless if they crash through and alter a gene in one of our chromosomes. You can avoid them only if you live underground, in a place like Zion, the city in the Matrix films. The mutations they induce keep plants and animals evolving and help explain why today’s cats and cabbages look different from their analogues from a hundred million years ago.

It’s now clear: we’re continually hit and penetrated by many different unseen particles and waves. Some of it is harmful. If this worries you and you tell a therapist of your concerns, you will be advised to come more regularly. To which you might then suggest that future sessions be held in an underground parking garage.

Nowadays the blanket term radiation can mean any kind of invisible high-speed detritus, but usually the word pertains to just those that can produce genetic defects and cancer. They include short waves, such as X-rays and gamma rays, as well as solid particles, such as those cosmic-ray protons and the even more massive alpha particles.

The universe is filled with radiation. It’s everywhere. It comes up from the ground and down from the sky. Most people are clueless about it. They don’t even know what radiation is. They don’t grasp its dangers. Yet we can easily calculate our personal yearly exposure.3

We measure exposure in millirems. Except for those who get periodic medical CAT scans, the average person gets 360 mrems a year, of which 82 percent comes from natural sources—even when we’re far from any health food store. This radiation is responsible for some of the spontaneous tumors that have always plagued the human race.

Our atmosphere blocks some of it, but the higher up you live, the more you get.

Nonetheless, and curiously, Tibetans and Peruvians, who spend their lives at high altitudes and therefore receive much more radiation than folks in Newark, New Jersey, don’t suffer increased rates of leukemia. And a major 2006 French study showed no increased cancer incidence in children who live near nuclear power plants. These, however, are minor radiation sources. They are dwarfed ten thousand times over by the “top three,” which we will get to in a moment.

If you’re concerned about all this high-speed detritus zipping through your favorite organs, here’s how you can calculate your personal annual exposure.

First the biggies:

Award yourself 26 mrem just for living on the surface of the earth.

Add 5 mrem for each thousand-foot elevation of your home. If you live in Denver you have to add 25 mrem, since you’re closer to those cosmic rays.

Is your home stone, brick, or concrete? Anything but wood frame? Add 7 mrem. These materials are slightly radioactive. Your real-estate agent probably never mentioned this.

Do you have a below-grade basement? If radon is present, add at least 250 mrem; this is a genuine biggie. The average homeowner gets most of her yearly radiation this way—from radon. It’s the densest gas you’re ever likely to encounter. It therefore likes to accumulate on your lowest floors. It is also the only gas that has only radioactive isotopes, so it’s a health hazard, no questions asked.

Radon is created when uranium and thorium decay, and these elements lie beneath many houses. Here’s something odd: the decay of radon gas itself produces new radioactive elements that are always solids. These stick to dust particles in the air and get inhaled into lungs. This is the single greatest cause of lung cancer after smoking. But some homes have none of it. An inexpensive test can let you know. In basements that do emit radon, it tends to accumulate, though it is easily remediable by the use of venting fans.

Add 40 mrem for the radiation you get from food and water. This is unavoidable.

Award yourself 50 mrem for the natural radiation emanating from within your own body—from potassium, for example, if you’re fond of bananas. Yikes! Eat a single banana and you’ve received more radiation than your friends who live next to a nuclear power plant get in an entire year.

Add 1 mrem for radiation in the air left over from those atomic tests in the 1950s. This, too, is unavoidable. You knew those bastards were screwing around with everyone’s children’s future health. We are those children.

Now for the major radiation sources you could avoid:

Add 1 mrem for each thousand miles you travel by jet this year. A single round-trip from Washington to Los Angeles gives you 6 mrem. That’s why the professional pilots and crew who get all this daily radiation have a 1 percent greater rate of cancer than the rest of us. Their rate is twenty-three cases per hundred people instead of twenty-two for the general population. They don’t tell this to prospective pilots taking flying lessons.