ASTROPHYSICIST_ RICHARD A. MULLER One Disaster after Another The father of the idea that a sibling of the periodically wreaks havoc on finds inspiration in catastrophes

Profile ERKELEY, CALIF.—I first meet Richard A. Muller during a record-breaking heat wave. The astrophysicist is on his way Bto get a refreshment. Bottles of his favor- ite cold dairy drink—mocha milk—are stacked in a nearby vending machine. Through the clear front, the scientist no- tices something out of place: a juice can trapped obliquely against the glass. “I’ll get either two drinks or none,” he pre- dicts playfully, inserting his change and selecting the beverage he thinks is most likely to knock the can free. Muller is un- concerned (or perhaps oblivious) that this selection is vanilla, not the flavor he came for. His purchase grazes the target but fails to knock the bottle down. Gambles like this one typify the life of Richard Muller—although usually the stakes are higher. The restless researcher loves to prowl for new scientific territory to conquer. “You need to have one inter- esting idea every day,” he says. His gradu- ate research concerned particle physics, but his accomplishments range from in- venting an improved technique for car- bon dating to designing an experiment for measuring the cosmic background ra- diation left over from the big bang about 15 billion years ago. These and other accomplishments won Muller a MacArthur Fellowship in 1982, RICHARD A. MULLER: SCIENTIFIC FREE SAFETY a year after these so-called genius awards • Born in New York City, 1944; wife, Rosemary, heads architectural firm; two daughters, Betsy and Melinda began. It was a turning point. After that, • Published novel on the life of Jesus, providing commonsense explanations of miracles (water walking Muller felt liberated to do “crazy things,” done by surreptitious use of a submerged dock, for example) as he puts it. “Just like James Bond has a • Invention in progress: A way to spray water 10 kilometers or more to extinguish fires license to kill, I had a license to depart • Professional philosophy: “My best achievements have come when I strike out and do something crazy” from the normal path of a scientist.” On the surface at least, he fits the stereo- type of a scientist. He will head to the lab a two-foot-high stack. “My research has physicist to debunk a research paper show- in the middle of the night when an idea been one disaster after another,” Muller ing that Earth has sustained significant strikes him. His cluttered office, which puckishly offers. This well-rehearsed line plant and animal extinctions at regular overlooks the Berkeley campus of the is quite literally true. He did work on the intervals—every 26 million years. Alvarez University of California, where he has big bang. He studied the violent superno- and his son, Walter, had recently advanced been since he received his Ph.D. in parti- va explosion preceding the creation of the theory that dinosaurs were the casu- cle physics here 32 years ago, could be a the sun. And then there’s his . alty of a Mount Everest–size comet that set from an absentminded-professor com- “Nemesis” refers to a seemingly bi- hit the planet 65 million years ago. At the edy. There’s hardly enough floor space zarre hypothesis concerning the evolu- time, the hypothesis was scoffed at; now for a visitor amid filing cabinets and tion of life on Earth. Muller hatched it it is generally accepted. Playing devil’s desks and cartons overflowing with jour- one day in 1983 when his mentor, Nobel advocate for Alvarez, Muller conjured up nals and papers. His in-box groans under laureate Louis Alvarez, enlisted the young a scenario. Suppose, he suggested, the sun EDWARD CALDWELL EDWARD

30 Scientific American February 2001 Profile has a sibling around which it do-si-dos nations gives him a strategic opportuni- enough difference in sunlight reaching every 26 million years. And suppose that ty: “That’s where the discoveries are.” Earth to produce ice ages. Another prob- once each revolution the swings Most recently, Muller has begun delv- lem is that some ice ages appear to have through the , a calving ground ing into the ice ages. Geologists still have begun before the orbital changes that for comets between four trillion and 10 a hard time explaining why they come supposedly caused them. trillion miles from us. Perhaps some of and go. Muller insists the answer is of Although adherents think that more those icy balls, of which there are billions, much more than academic interest. research will explain such conflicts, Muller would be knocked off-kilter and sent Springing from his office chair, he heads believes the textbook Milankovitch theory hurtling into Earth. to a blackboard in an adjoining room— is hopelessly flawed. His own answer rests At first the idea seemed preposterous, he couldn’t locate any chalk in his office— on a different aspect of Earth’s orbit: Imag- Profile even to Muller himself. But neither Muller and sketches a graph of global tempera- ine the is a vinyl record. Earth nor Alvarez could think of any reason ture since the industrial revolution. Over- travels precisely on the record, called the why the theory couldn’t be true. With a all, global temperature has gone up about ecliptic, only some of the time. At other touch of whimsy, Muller dubbed the star 1.5 degrees Fahrenheit in the past 120 times, the orbit is inclined a few degrees to Nemesis, after the Greek goddess who years—and 15 to 20 degrees since glaciers the disk. Over a 100,000-year cycle, Earth’s fends off human folly. “We worry that if orbit begins in the ecliptic, rises out of it, the companion is not found,” he stated then returns to where it started. This in the scientific article introducing the slow rocking, Muller proposes, is responsi- theory, “this paper will be our nemesis.” ble for Earth’s ice ages. He says the regions It seems counterintuitive that the solar above and below the ecliptic are laden system could be looping around an un- with cosmic dust, which cools the planet. known star, but in fact most have Muller’s inclination theory got a shot partners: some 85 percent have some in the arm in 1995, when Kenneth Farley, kind of companion. The only way to a geochemist at the California Institute of identify which, if any, of the catalogued Technology, published a paper on cosmic stars is the sun’s sibling requires measur- dust found in sea sediments. He began ing the distances to them. Muller says the research expecting to give Muller’s the elliptical orbit of Nemesis would get theory a knockout punch but discovered no farther than about 18 trillion miles that cosmic dust levels do indeed wax from Earth, about three light-years away and wane in sync with the ice ages. and three quarters the distance to the But most researchers seem to echo the closest known star, Alpha Centauri. It sentiment of Wallace Broecker, a geochem- could be a star, which might be ist at Columbia University, who thinks bright enough to be seen with a small tele- Muller is fooling himself. In 1996 Broeck- scope, or, less likely, a brown dwarf, which er brought a group of top-flight climate might not be visible at all. INVADING ICE, from this January 1929 researchers together to hear Muller’s the- When he dreamed up the theory near- issue of Amazing Stories, sparked a ory. He says they found the presentation ly two decades ago, Muller thought he young Muller’s interest in ice ages. “riveting,” but “they didn’t buy it.” would locate Nemesis in just a few years. “There’s no mechanism attached to the Given its putative distance and bright- idea,” states Nicholas J. Shackleton, a ma- ness, it should be easy to find such a star receded 12,000 years ago. “Anything that rine geologist at the University of Cam- through parallax measurements—seeing can have an impact of 15 degrees is proba- bridge and a leading proponent of the how it shifts against the more distant bly having an impact on the present cli- Milankovitch theory. He questions how stellar background as Earth moves along mate,” he reasons. small changes in interplanetary dust could in its orbit. But the search, short on funds Ice ages come and go at approximately result in effects as dramatic as the coming for telescope time, languished and stalled. 100,000-year intervals. The conventional and going of ice ages. Muller responds Muller says most astronomers think his explanation, refined and popularized by that dust from space influences cloud theory was disproved, when in fact it is Serbian mathematician Milutin Milanko- cover on Earth and could have profound simply in limbo. vitch in the decades before World War II, climatic implications. He says his theory, It is no coincidence that so much of his involves subtle irregularities in Earth’s if viewed objectively, does just as well at career has been spent studying such tu- motion. The theory mainly posits that explaining the facts as Milankovitch’s. multuous events. For centuries, scientists the eccentricity, or out-of-roundness, of Referring to football, Muller calls him- have predicated theories about Earth’s Earth’s orbit varies the amount of sun- self a free safety of science, a generalist evolution on the principles of uniformi- light bathing our planet. who scores intellectual touchdowns be- tarianism and gradualism, which posit Painstaking reconstructions of Earth’s cause he is unrestrained by questionable that by and large the planet evolved slow- past movements show that the planet’s preconceived ideas. “Every once in a while ly, relying on the same forces we see at orbit around the sun goes from almost there’s a fumble” that no one notices, work today, such as erosion and conti- perfectly round to slightly oval and back Muller says, “and I can grab that ball and nental drift. Muller, however, believes in- in 100,000 years, matching the interval run into the end zone.” —Daniel Grossman frequent, violent events are just as impor- between ice ages. But there are problems. tant—a doctrine some call catastrophism. For instance, the modest change in or- DANIEL GROSSMAN is a freelance writer Muller says neglect of catastrophic expla- bital eccentricity does not make nearly based in Watertown, Mass. COURTESY OF WIZARDS OF THE COAST 2000

32 Scientific American February 2001 Profile