Death By Black Hole & Other Cosmic Quandaries

by Neil DeGrasse Tyson

  When people believe a tale that conflicts with self-checkable evidence it tells me that people undervalue the role of evidence in formulating an internal belief system. Why this is so is not clear, but it enables many people to hold fast to ideas and notions based purely on supposition. But all hope is not lost. Occasionally, people say things that are simply true no matter what. One of my favorites is, “Wherever you go, there you are” and its Zen corollary, “If we are all here, then we must not be all there.”

  THIRTY-FIVE

  FEAR OF NUMBERS

  We may never know the circuit diagram for all the electrochemical pathways within the human brain. But one thing is for certain, we are not wired for logical thinking. If we were, then mathematics would be the average person’s easiest subject in school.

  In this alternate universe, mathematics might not be taught at all because its foundations and principles would be self-evident even to slow-achieving students. But nowhere in the real world is this true. You can, of course, train most humans to be logical some of the time, and some humans to be logical all of the time; the brain is a marvellously flexible organ in this regard. But people hardly ever need training to be emotional. We are born crying, and we laugh early in life.

  We do not emerge from the womb enumerating objects around us. The familiar number line, for example, is not writ on our gray matter. People had to invent the number line and build upon it when new needs arose from the growing complexities of life and of society. In a world of countable objects, we will all agree that 2 + 3 = 5, but what does 2–3 equal? To answer this question without saying, “It has no meaning,” required that somebody invent a new part of the number line—negative numbers. Continuing: We all know that half of 10 is 5, but what is half of 5? To give meaning to this question, somebody had to invent fractions, yet another class of numbers on the number line. As this ascent through numberdom progressed, many more kinds of numbers would be invented: imaginary, irrational, transcendental, and complex, to name a few. They each have specific and sometimes unique applications to the physical world that we have discovered around us from the dawn of civilization.

  Those who study the universe have been around from the beginning. As a member of this (second) oldest profession, I can attest that we have adopted, and actively use, all parts of the number line for all manner of heavenly analysis. We also routinely invoke some of the smallest and, of course, largest numbers of any profession. This state of mind has even influenced common parlance. When something in society seems immeasurably large, like the national debt, it’s not called biological or chemical. It’s called astronomical. And so one could argue strongly that astrophysicists do not fear numbers.

  With thousands of years of culture behind us, what has society earned on its math report card? More specifically, what grade do we give Americans, members of the most technologically advanced culture the world has ever known?

  Let’s start with airplanes. Whoever lays out the seats on Continental Airlines seems to suffer from Medieval fears of the number 13. I have yet to see a row 13 on any flight I have taken with them. The rows simply go from 12 to 14. How about buildings? Seventy percent of all high-rises along a three-mile stretch of Broadway in Manhattan have no thirteenth floor. While I have not compiled detailed statistics for everywhere else in the nation, my experience walking in and out of buildings tells me it’s more than half. If you’ve ridden the elevator of these guilty high-rises you’ve probably noticed that the 14th floor directly follows the 12th. This trend exists for old buildings as well as new. Some buildings are self-conscious and try to conceal their superstitious ways by providing two separate elevator banks: one that goes from 1 to 12 and another that goes upward from 14. The 22-story apartment building in which I was raised (in the Bronx) had two separate banks of elevators, but in this case, one bank accessed only the even floors while the other bank accessed the odd. One of the mysteries of my childhood was why the odd bank of elevators went from floor 11 directly to floor 15, and the even bank went from 12 to 16. Apparently, for my building, a single odd floor could not be skipped without throwing off the entire odd-even scheme. Hence the blatant omission of any reference to either the 13th or the 14th floor. Of course, all this meant that the building was actually only 20 stories high and not 22.

  In another building, which harbored an extensive subterranean world, the levels below the first floor were B, SB, P, LB, and LL. Perhaps this is done to give you something to think about while you are otherwise standing in the elevator doing nothing. These floors are begging to become negative numbers. For the uninitiated, these abbreviations stood for Basement, Sub-Basement, Parking, Lower Basement, and Lower Level. We surely do not use such lingo to name normal floors. Imagine a building not with floors labelled 1, 2, 3, 4, 5, but G, AG, HG, VHG, SR, R, which obviously stand for Ground, Above Ground, High Ground, Very High Ground, Sub-Roof, and Roof. In principle, one should not fear negative floors—they don’t in the Hotel de Rhone in Geneva, Switzerland, which has floors—1 and—2, nor are they afraid at the National Hotel in Moscow, which had no hesitation naming floors 0 and—1.

  America’s implicit denial of all that is less than zero shows up in many places. A mild case of this syndrome exists among car dealers, where instead of saying they will subtract $1,000 from the price of your car, they say you will receive $1,000 “cash back.” In corporate accounting reports, we find that fear of the negative sign is pervasive. Here, it’s common practice to enclose negative numbers in parentheses and not to display the negative symbol anywhere on the spreadsheet. Even the successful 1985 Bret Easton Ellis book (and 1987 film) Less Than Zero, which tracks the falling from grace of wealthy Los Angeles teens, could not be imagined with the logically equivalent title: Negative.

  As we hide from negative numbers, we also hide from decimals, especially in America. Only recently have the stocks traded on the New York Stock Exchange been registered in decimal dollars instead of clunky fractions. And even though American money is decimal metric, we don’t think of it that way. If something costs $1.50, we typically parse it into two segments and recite “one dollar and fifty cents.” This behavior is not fundamentally different from the way people recited prices in the old decimal-averse British system that combined pounds and shillings.

  When my daughter turned 15 months old, I took perverse pleasure in telling people she was “1.25.” They would look back at me, with heads tilted in silent puzzlement, the way dogs look when they hear a high-pitched sound.

  Fear of decimals is also rampant when probabilities are communicated to the public. People typically report odds in the form of “something to 1.” Which makes intuitive sense to nearly everyone: The odds against the long-shot winning the ninth race at Belmont are 28 to 1. The odds against the favorite are 2 to 1. But the odds against the second favorite horse are 7 to 2. Why don’t they say “something to 1”? Because if they did, then the 7 to 2 odds would instead read 3.5 to 1, stupefying all decimal-challenged people at the racetrack.

  I suppose I can live with missing decimals, missing floors to tall buildings, and floors that are named instead of numbered. A more serious problem is the limited capacity of the human mind to grasp the relative magnitudes of large numbers:

  Counting at the rate of one number per second, you will require 12 days to reach a million and 32 years to count to a billion. To count to a trillion takes 32,000 years, which is as much time as has elapsed since people first drew on cave walls.

  If laid end to end, the hundred billion (or so) hamburgers sold by the McDonald’s restaurant chain would stretch around the Earth 230 times leaving enough left over to stack the rest from Earth to the Moon—and back.

  Last I checked, Bill Gates was worth $50 billion. If the average employed adult, who is walking in a hurry, will pick up a quarter from the sidewalk, but not a dime, then the corresponding amount of money (given their relative wealth) that Bill Gates would ignore if he saw it lying on the street is $25,000.

  These are trivial
brain exercises to the astrophysicist, but normal people do not think about these sorts of things. But at what cost? Beginning in 1969, space probes were designed and launched that shaped two decades of planetary reconnaissance in our solar system. The celebrated Pioneer, Voyager, and Viking missions were part of this era. So too was the Mars Observer, which was lost on arrival in the Martian atmosphere in 1993.

  Each of these spacecraft took many years to plan and build. Each mission was ambitious in the breadth and depth of its scientific objectives and typically cost taxpayers between $1 and $2 billion. During a 1990s change in administration, NASA introduced a “faster, cheaper, better” paradigm for a new class of spacecraft that cost between $100 and $200 million. Unlike previous spacecraft, these could be planned and designed swiftly, enabling missions with more sharply defined objectives. Of course that meant a mission failure would be less costly and less damaging to the overall program of exploration.

  In 1999, however, two of these more economical Mars missions failed, with a total hit to taxpayers of about $250 million. Yet public reaction was just as negative as it had been to the billion-dollar Mars Observer. The news media reported the $250 million as an unthinkably huge waste of money and proclaimed that something was wrong with NASA. The result was an investigation and a congressional hearing.

  Not to defend failure, but $250 million is not much more than the cost to produce Kevin Costner’s film flop Waterworld. It’s also the cost of about two days in orbit for the space shuttle, and it’s one-fifth the cost of the previously lost Mars Observer. Without these comparisons, and without the reminder that these failures were consistent with the “faster, cheaper, better” paradigm, in which risks are spread among multiple missions, you would think that $1 million equals $1 billion equals $1 trillion.

  Nobody announced that the $250-million loss amounts to less than $1 per person in the United States. This much money, in the form of pennies, is surely just laying around in our streets, which are filled with people too busy to bend down and pick them up.

  THIRTY-SIX

  ON BEING BAFFLED

  Maybe it’s the need to attract and keep readers. Maybe the public likes to know those rare occasions when scientists are clueless. But how come science writers can’t write an article about the universe unless they describe some of the astrophysicists they interview as being “baffled” by the latest research headlines?

  Scientific bafflement so intrigues journalists that, in what may have been a first for media coverage of science, an August 1999 page-one story in The New York Times reported on an object in the universe whose spectrum was a mystery (Wilford 1999). Top astrophysicists were stumped. In spite of the data’s high quality (observations were made at the Hawaii-based Keck telescope, the most powerful optical observatory in the world), the object wasn’t any known variety of planet, star, or galaxy. Imagine if a biologist had sequenced the genome of a newly discovered species of life and still couldn’t classify it as plant or animal. Because of this fundamental ignorance, the 2,000-word article contained no analysis, no conclusions, no science.

  In this particular case, the object was eventually identified as an odd, though otherwise unremarkable, galaxy—but not before millions of readers had been exposed to a parade of selected astrophysicists saying, “I dunno what it is.” Such reporting is rampant, and grossly misrepresents our prevailing states of mind. If the writers told the whole truth, they would instead report that all astrophysicists are baffled daily, whether or not their research makes headlines.

  Scientists cannot claim to be on the research frontier unless one thing or another baffles them. Bafflement drives discovery.

  Richard Feynman, the celebrated twentieth-century physicist, humbly observed that figuring out the laws of physics is like observing a chess game without knowing the rules in advance. Worse yet, he wrote, you don’t get to see each move in sequence. You only get to peek at the game in progress every now and then. With this intellectual handicap, your task is to deduce the rules of chess. You may eventually notice that bishops stay on a single color. That pawns don’t move very fast. Or that a queen is feared by other pieces. But how about late in the game when only a few pawns are left. Suppose you come back and find one of the pawns missing and a previously captured queen resurrected in its place. Try to figure that one out. Most scientists would agree that the rules of the universe, whatever they may look like in their entirety, are vastly more complex than the rules of chess, and they remain a wellspring of endless bafflement.

  I LEARNED RECENTLY that not all scientists are as baffled as astrophysicists. This could mean that astrophysicists are stupider than other breeds of scientists, but I think few would seriously make this claim. I believe that astrophysical bafflement flows from the staggering size and complexity of the cosmos. By this measure, astrophysicists have much in common with neurologists. Any one of them will assert, without hesitation, that what they do not know about the human mind vastly surpasses what they do know. That’s why so many popular-level books are published annually on the universe and on the human consciousness—nobody’s got it right yet. One might also include meteorologists in the ignorance club. So much goes on in Earth’s atmosphere that can affect the weather, it’s a wonder meteorologists predict anything accurately. The weather people on the evening news are the only reporters on the program who are expected to predict the news. They try hard to get it right but, in the end, all they can do is quantify their bafflement with statements like “50 percent chance of rain.”

  One thing is for certain, the more profoundly baffled you have been in your life, the more open your mind becomes to new ideas. I have firsthand evidence of this.

  During an appearance on the PBS talk show Charlie Rose, I was pitted against a well-known biologist to discuss and evaluate the evidence for extraterrestrial life as revealed in the nooks and crannies of the now-famous Martian meteorite ALH84001. This potato-shaped, potato-sized interplanetary traveler was thrust off the Martian surface by the impact of an energetic meteor, in a manner not unlike what happens to loose Cheerios as they get thrust off a bed when you jump up and down on the mattress. The Martian meteorite then traveled through interplanetary space for tens of millions of years, crashed into Antarctica, stayed buried in ice for about 10,000 years, and was finally recovered in 1984.

  The original 1996 research paper by David McKay and colleagues presented a string of circumstantial evidence. Each item, by itself, could be ascribed to a nonbiogenic process. But taken together, they made a compelling case for Mars’s having once harbored life. One of McKay’s most intriguing, but scientifically empty, pieces of evidence was a simple photograph of the rock, taken with a high-resolution microscope showing a teeny-weeny worm-looking thing, less than one-tenth the size of the smallest known worm creatures on Earth. I was (and still am) quite enthusiastic about these findings. But my biology co-panelist was argumentatively skeptical. After he chanted Carl Sagan’s mantra “extraordinary claims require extraordinary evidence” a few times, he declared that the wormy thing could not possibly be life because there was no evidence of a cell wall and that it was much smaller than the smallest known life on Earth.

  Excuse me?

  Last I checked the conversation was about Martian life, not the Earth life he had grown accustomed to studying in his laboratory. I could not imagine a more close-minded statement. Was I being irresponsibly open-minded? It is, indeed, possible to be so open-minded that important mental faculties have spilled out, like those who are prone to believe, without skepticism, reports of flying saucers and alien abductions. How is it that my brain could be wired so differently from that of the biologist? He and I both went to college, then graduate school. We got our PhDs in our respective fields and have devoted our lives to the methods and tools of science. Perhaps we needn’t look far for the answer. Publicly and among themselves biologists rightly celebrate the diversity of life on Earth from the marvelous variations wrought by natural selection and expressed by differences
in DNA from one species to the next. At the end of the day, however, their confession is heard by no one: they work with a single scientific sample—life on Earth.

  I’D BET ALMOST anything that life from another planet, if formed independently from life on Earth, would be more different from all species of Earth life than any two species of Earth life are from each other. On the other hand, the objects, classification schemes, and data sets of the astrophysicist are drawn from the entire universe. For this simple reason, new data routinely pushes astrophysicists to think outside the proverbial box. And sometimes our whole bodies get shoved completely outside the box.

  We could go back to ancient times for examples, but that’s unnecessary. The twentieth century will do just fine. And many of these examples we have already discussed:

  Just when we thought it was safe to look up at a clockwork universe, and bask in our deterministic laws of classical physics, Max Planck, Werner Heisenberg, and others had to go and discover quantum mechanics, demonstrating that the smallest scales of the universe are inherently nondeterministic even if the rest of it is.

  Just when we thought it was safe to talk about the stars of the night sky as the extent of the known cosmos, Edwin Hubble had to go and discover that all the spiral fuzzy things in the sky were external galaxies—veritable “island universes,” adrift far beyond the extent of the Milky Way’s stars.