On Being Baffled

Natural History Magazine

by Neil deGrasse Tyson

From Natural History Magazine, May 2002

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, a August 1999 page-one story in the New York Times reported on an object in the universe whose spectrum was a mystery. 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. It was as though 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 2000- 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. Even Isaac Newton, the person who formulated some of history's most successful theories of the universe, remained perpetually baffled. In his later life, Newton said of himself:

I do not know what I appear to the world; but to myself I seem to have been only like a boy playing on a sea shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

Richard Feynman, the celebrated twentieth-century physicist, made a similarly humble observation 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 their degree of 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 ten thousand years, and was finally recovered in 1984.

The original 1996 research paper by David MacKay and colleagues presented a string of circumstantial evidence. Each item, by itself, could be ascribed to non-biogenic process. But taken together, they made a compelling case for Mars's having once harbored life. One of MacKay'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 to which 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 Ph.D.s 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:

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 non-deterministic even if the rest of it is.

Just when we though 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.

Just when we thought we had the size and shape of our presumably eternal cosmos figured out, Edwin Hubble went on to discover that the universe was expanding, and that the galactic universe extended as far as the largest telescopes could see. One consequence of this discovery was that the cosmos had a beginning—an unthinkable notion to all previous generations of scientists.

Just when we thought that Albert Einstein's relativity theories would enable us to explain all the gravity of the universe, the Caltech astrophysicist Fritz Zwicky discovered dark matter, a mysterious substance that wields ninety percent of all the gravity of the universe, but emits no light and has no other interactions with ordinary matter. The stuff is still a mystery. Fritz Zwicky further identifies and characterizes a class of object in the universe called supernovae, which are single, exploding stars that temporarily emit the energy equivalent of a hundred billion suns.

Not long after we figure out the ways and means of supernova explosions, somebody discovers bursts of gamma rays from the edge of the universe that temporarily outshine all the energy-emitting objects of the rest of the universe combined. On the brink of running out of hyperbolic language, some have referred to gamma ray bursts as hyper-novae.

And just as we growing accustomed to living in our ignorance of dark matter's true nature, two research groups working independently, one led by Berkeley astrophysicist Saul Perlmutter and one led by Harvard astrophysicist Robert Kirshner, discovered that the universe is not just expanding, it's accelerating. The cause? Evidence indicates a mysterious pressure within the vacuum of space that acts in the opposite direction of gravity and which remains more of a mystery than dark matter.

These are, of course, just an assortment of the countless mind-bending and brain-boggling phenomena that have kept astrophysicists busy for the past one hundred years. I could stop the list here, but I would be remiss if I did not include the discovery of neutron stars, which pack the mass of the Sun within a ball that measures barely a dozen miles across. To achieve this density at home, just cram a herd of 50-million elephants into the volume of a thimble.

No doubt about it. My mind is wired differently from that of a biologist, and so our different reactions to the evidence for life in the Mars meteorite was understandable, if not entirely expected.

Lest I leave you with the impression that the behavior of research scientists is indistinguishable from that of freshly beheaded chickens running aimlessly around the coup, you should know that the body of knowledge about which scientists are not baffled is impressive. It forms most of the contents of introductory college textbooks and comprises the modern consensus of how the world works. These ideas are so well understood that they no longer form interesting subjects of research and are no longer a source of confusion.

I once hosted and moderated a panel discussion on theories of everything—those wishful attempts to explain under one conceptual umbrella all the forces of nature. On the stage were five distinguished and well-known physicists. Midway through the debate I nearly had to break up a fight as one of them looked like he was ready to throw a punch. That's okay. I didn't mind it. The lesson here is if you ever see scientists engaged in a heated debate, they are arguing because they are all baffled. These physicists were arguing on the frontier about the merits and shortcomings of string theory, not whether Earth orbits the Sun, whether the heart pumps blood to the brain, or whether rain falls from clouds.