The laws of the universe are based on fixed constants. What happens to science when those number start to change?
In Oklo, Gabon, a rocky region in western Africa, sits a galactic marvel: the only known natural nuclear fission reactor. It stirred to life some 1.7-billion years ago, and when French scientists unearthed the dormant site in 1972, it caused a scientific roar. Some scientists argued that Oklo couldn’t have happened, while some fringe groups erred in the other direction, pouncing on Oklo as “evidence” for outlandish pet theories, like long-lost African civilizations and crash-landings by nuclear-powered alien star cruisers. Actually, as nuclear scientists soon determined, Oklo was powered by nothing but uranium, water, oxygen, and blue-green algae (i.e., pond scum). That was scarcely a less fantastical explanation, but one securely grounded in traditional science.
Nowadays, Oklo (left) has been relegated to a good yarn among scientists, an intellectual roadside attraction. But a small minority has always held out hope that Oklo would reveal something more. Not alien star-cruisers, but hints about the origin and fate of the universe. These scientists think that Oklo reveals something about figures known as “fundamental constants,” which are to physics what pi is to mathematics: fixed numbers that pop up in all sorts of contexts, for reasons that seem tantalizingly explainable but that have so far resisted deeper explanation.
But based on evidence from Oklo and other places, those “constants” might be changing. The important point is that the values of the constants define how the universe works and all its physical laws; so if constants drift and vary, we may live in a very different cosmos than scientists assumed. It would be as if you traveled back in time and performed an experiment ... and got a totally different answer than here and now.
It hasn’t been easy for scientists to tease out the effects of changing constants or even decide what changes are real and what aren’t. Some researchers change their minds year to year, and the back-and-forth has made the study of constants one of the more vibrant fields in physics recently.
One physicist studying the link between Oklo and fundamental constants is Yale University’s Steve Lamoreaux, a tall, heavyset man with thick-stemmed glasses and a military-like buzzcut for his white hair. He’s an agreeable fellow and tends to concur with almost everything you say before jumping in with his own explanation. His background is in measuring constants to eight or nine decimal points, in some of the most precise experiments ever undertaken.
Lamoreaux started looking at data from Oklo as an extension of that work (he jokingly referred to Oklo as his hobby). Though initially skeptical, he grew convinced that one of the more mysterious but beloved constants, the “fine structure constant” was changing. He wasn’t the first to conclude this, but work by him and others received almost as much attention around the world as the original Oklo find did.
Then, suddenly, Lamoreaux changed his mind. “The geologic evidence is convoluted and hard to understand,” he explains, and when he revised his work on Oklo recently with some different starting assumptions, he grew less optimistic. He determined that if the so-called constants drift at all they do so achingly slowly, a millionth of a billionth of a percent each year.
Some of Lamoreaux’s colleagues counter that looking back “only” 1.7-billion years, to Oklo, isn’t enough. Astronomers at two universities in Australia have claimed for a decade that they’ve peeked far enough back, about 13-billion years, to see measurable changes. One colleague of theirs even claims he’s seen fluctuations up to one percent—in this context, an astronomical number. Naturally, these claims have not gone unchallenged.
What’s more, this debate has not been limited to scientists. Fundamentalist Christian groups have quixotically taken up the cause, too. They hope to explain away the apparent age of the universe by fiddling with constants in just the right way to compress time and space to Genesis-friendly proportions, about six thousand years. This has not won them much credit or love from scientists. (In a recent lecture in New York, Lamoreaux chided them as “an ultra-conservative emotional movement [convinced] that Earth is five thousand years old.”)
Still, in a weird-bedfellows coincidence, physicists doing string theory, a candidate for a “grand unified theory” that explains all science in a few equations, have watched the work on constants with interest as well, since it might be the only way in the foreseeable future to test their esoteric ideas. Along those same lines, despairing astrophysicists have recently suggested that looking for changes in constants might help determine what exactly is the mysterious “dark energy” that makes up 70 percent of the universe and that causes the universe to grow at an accelerating rate.
As a result, debates about the fine structure and others constants will grow more fervid in the coming decade as new astronomical data allows scientists to peek farther and father back in time. The changes scientists fight over may seem ridiculously tiny, like Bill Gates losing a few pennies on the sidewalk. But it’s not the magnitude that’s important, it’s the possibility of constants changing, says Mike Murphy, an astronomer at Swinburne University of Technology, in Melbourne. “Any observation of a varying fundamental constant would basically require a completely new theory of physics,” he says. “It would be similar to the change ... when Einstein came up with general relativity: There was no everyday application of general relativity back then but people recognized that general relativity meant a completely new conceptual view of the universe.”
In the debate over varying constants, then, the fate of the cosmos may not be hanging in the balance, humankind’s understanding of it is.
To start at the beginning, fourteen billion years ago all matter was crammed into an infinitesimal dot and so tightly packed that the laws of physics “broke down,” as physicists say. Whether through luck, the fingernail flick of a First Mover, or an unknown law of science, that singularity exploded. Subatomic shrapnel flew out, and it soon settled down into recognizable protons, electrons, and atoms. Within minutes after the Big Bang, the story goes, the laws of physics and the values of the fundamental constants were etched onto the universe.
It took decades of work to sketch out that tidy story, which forms the basis for what’s known as the “standard model,” the standard story of the universe. But the standard model always made scientists a little uncomfortable, since it cannot explain where the laws and constants come from. “There seems no way, even in principle, that one could use the standard model to calculate them,” Murphy notes. “This, for many physicists, is a sure sign that there’s actually a more fundamental level of physics which we are yet to explain or understand.”
That hidden layer motivates the small but persistent band of people who study inconstant constants, and it leads them to spin a different story for the universe. They still believe in scientific laws, but instead of etched-on rules, perhaps looking back in time is like comparing football in different eras. Rules always existed in football, and at any point, everyone agreed upon what the rules were. But if life was short compared to a football season, you might conclude, quite reasonably, that the rules had been and would always be the same. Moreover, if stuck in a time of leather helmets and no faceguards, you would correctly conclude that it would violate the laws of that universe to throw a forward pass. But you might also conclude that forward passes were theoretically impossible.
In other words, maybe the rules of the universe, including the fundamental constants, evolve like the laws of football. This, too, is a great story, but so far, it’s been exceedingly difficult to tease out whether constants do vary. In many cases, the observed fluctuations are so small and have large enough margins of error that they might well be zero. The work hasn’t convinced most other scientists, either, who are comfortable with the enormously successful standard model and can marshal billions of data points from every physics journal ever published to show that the eternal laws sure do seem stable.
The stability debates center around one element of the standard model, the fine structure constant, usually referred to as “alpha.” Alpha has a simple role: It determines how strongly negatively charged electrons and positively charged protons bind together to form atoms. It’s a crucial parameter, and truly deserves the name fundamental.
But again, its origins are mysterious. This has lead many people to interpret alpha in mystical ways (see sidebar). Studies of alpha hit a high point in the 1960s when scientists began to argue that alpha seems “fine-tuned” to produce life in the universe, a conjecture known as the “anthropic principle.”
That principle says that if the universe had “chosen” a smaller value for alpha, nothing would exist but a fog of subatomic scraps because no atoms would ever form. If alpha had been a smidge larger, atoms would bind their electrons too tightly and never loan them out to form molecules like water and proteins. Theologians, philosophers, and many scientists concluded that the universe could not have hit upon this perfect fine structure constant by accident, but only if a creator had drawn up plans for it or if the universe was somehow programmed to produce life, perhaps even intelligent life.
So it was a big deal when an American scientist named Alexander Shlyakhter took a close look at the nuclear waste from the Oklo nuclear reactor and declared that alpha had been shrinking. Shlyakhter compared the Oklo waste to waste man-made reactors produce today. Though in both cases the nuclear waste was similar, he found that Oklo produced a bit too much of some byproducts and not quite enough of others.
Most importantly, Shlyakhter calculated that if the fine structure constant had been slightly smaller when Oklo went nuclear 1.7-billion years ago, then the discrepancies were easy to explain. Perhaps alpha was not “tuned” to value life after all.
In the decades since, some scientists have supported Shlyakhter’s work, some have contradicted it. Some, like Lamoreaux, have done both, depending on the best evidence at the moment. But all Oklo measurements suffer from imprecision because no one knows the exact geological details of the reactor, nor how much (if any) of its byproducts have eroded away. The stakes of the debate but the paucity of reliable data is the reason so much heat and so little light has been produced by debates over Oklo.
Plus, as Murphy, the Australian astronomer, points out, conditions even 1.7-billion years ago reveal little about the very early hours of the universe, when fundamental constants perhaps varied much more.
A fortiori, this fact limits the experiments today that look how much alpha varies year to year. Murphy praised some recent studies with ultra-precise “atomic clocks,” which found one-year variations in alpha of effectively zero. But he adds, “The usual temptation is to say that if you can do a laboratory experiment very precisely then you can reliably extrapolate the constancy of alpha back through the history of the Universe ... But this is just wrong. It was outed as being a false and all-too-comforting argument by [physicist Paul] Dirac in the 1960s.”
Avoiding the Oklo morass, Murphy studies alpha by looking at quasars, which provide cleaner data. Quasars (left, an artist's rendition) are enormous star systems with black holes in their navels. As the black hole devours stars, the system spins and emits light like a massive twirling lighthouse beacon. Because many quasars formed long ago, astronomers can use them as a snapshot of the early the universe, just a billion years after formation.
While Murphy was very careful to say his group might be proven wrong—“Extraordinary claims require extraordinary evidence,” he says, a dictum that every scientist in this field has ready on his lips—Murphy’s team has concluded, tentatively, that alpha has crept upward 0.0001 percent in 13-billion years. That percent change is significant enough that, unless scientists can poke holes in Murphy’s methods or analysis, they cannot argue, as Lamoreaux does with his Oklo work, that the change is probably zero.
But why, you might be wondering, do scientists focus so myopically on alpha? There are far more interesting and recognizable constants, like the speed of light or charge on an electron, which is the basis for electricity and all electric devises. The fine structure constant is even defined in terms of the speed of light and electron’s charge, so if alpha changes, one or both of those things has to change, too. Why not look at them instead?
Unfortunately, the science gets tricky and philosophical here, like a Zen koan. If the speed of light or an electron’s charge was slowing down or shrinking everywhere, then the instruments to detect those changes would slow down or shrink in the exact same way. All measurable effects would cancel out. In fact, that paradox will prevent you from measuring changes in any constant that has units, like seconds, or feet, or kilograms.
Alpha, in contrast, is a pure number; it has no units. It affects only how atoms stick together or fall apart and how they behave, which you can observe without units. The upshot is that alpha is the only door into “inconstants.”
Thankfully, there may be a way around that paradox, through string theory. String theory purports to look at matter on its fundamental level, billions of times smaller than atoms. And according to Victor Flambaum, a theoretical physicist at the University of New South Wales who collaborates with Murphy, some versions of string theory claim they can tweeze out if the speed of light or something else was changing.
It would work like this. String theory proposes that the universe has more than three dimensions, in some cases up to eleven. Those extra dimensions are extremely tiny and are usually described as “curled up” and undetectable. However, if those dimensions started to unfurl, even minutely—sort of like a two-dimensional “Flatland” growing a third dimension—this might look to human beings like shifts in alpha. Moreover, different versions of string theory say that shifts in different constants, like the speed of light, cause the unfurling dimensions. So depending on which version looked best, scientists might be able to figure out what’s changing, even if they cannot measure it.
Of course, string theory’s status as a pure, rarefied theory has a downside—there’s no way to actually test it. That’s actually a long-simmering complaint among scientists about string theory, and it has frothed over in recent years. (Books with unforgiving titles like Not Even Wrong and The Trouble With Physics have become big sellers.) But the discovery of a fundamental inconstant would provide a tiny bit of supporting evidence against those complaints. Variations “would probably gladly be accepted by string theorists,” says Flambaum. “If they can accommodate variations easily it’s a good argument in favor of string theory.”
Flambaum, though not a string theorist himself, is doing what he can to help string theory out. His latest experiment results looked back to one minute after the Big Bang, and he claimed he found a variation of alpha around 1 percent—which in this field is a huge number.
Flambaum has other interesting ideas about constants, too, and like astronomers from a few decades ago, he explicitly links alpha with the origins of life. Not only does Flambaum think alpha varies in time, he thinks it varies from one part of the universe to another. To return to the football analogy, perhaps the rulebook varies not only with time, but there might be two leagues, like the NFL and the Canadian Football League, playing slightly different games in adjacent real estate.
Flambaum says this might also explain why life arose on a seemingly random planet in a seemingly unremarkable pocket of space. Only on Earth, he says, were cosmological conditions right for sturdy atoms and full molecules. “It’s like how we live on Earth because there is water here and not the moon,” says Flambaum. “It’s the same with fundamental constants, why we live where we do.”
Some scientists have staked careers on varying fundamental constants. But they’ve nowhere near as much riding on the outcome as some religious groups. Creationists have seen varying constants as a “great resource for refuting the ‘big bang,’” as one creationist website had it. What’s more, the people who practice the curious amalgam called “creationist science” hope that varying constants can reconcile their belief that God created Earth six thousand years ago with the scientific consensus that He most certainly did not.
Creationists have taken up the inconstant debate with two goals. The first is tactical: to sow doubt, like opponents of evolution sow doubt by pointing out what they see as inconsistencies. One outfit, Creation Ministers International, has quibbled on its website that “if something as supposedly immutable as [fundamental scientific constants], a part of the ‘hard’ operational science of physico-chemistry, is open to question, then there is even less reason to reinterpret Scripture on the more contentious areas dealing with the past, i.e. the latest ‘missing links,’ radiometric ‘dates,’ or geological features supposedly incompatible with a world-wide Flood.”
For their second goal, creationists aim to recalibrate natural history. Almost everyone agrees that light from stars records, or at least appears to record, events that happened billions of years ago. To explain this, some creationists argue that God created a universe with light “already on the way” to test believers. (They make similar claims about dinosaur bones.) Others, however, have trouble with that idea, since it would be deceptive and unworthy of God. However, if the speed of light were billions of times larger in the past the problem evaporates.
There are other constants that creationists fiddle with as well. Eugene Chaffin, a creationist physicist at Bob Jones University, has done work on refuting the age of the Oklo reactor, which he first came across during his days in the Navy teaching young sailors about nuclear submarines. But Oklo holds less interest for him than another basic constant, called “mu.” Mu is the ratio of the proton mass to the electron mass, and it’s related to how strongly an atom’s nucleus holds together, and how strong a nucleus resists radioactive disintegration.
“I believe in the Genesis Flood, which would probably get some snickers from the guys you talk to,” he says. But Chaffin believes The Deluge could have precipitated “a large change in the coupling constants [i.e., mu] that affect radioactive decays, which gives the appearance that there were billions of years that have gone by.”
In other words, Chaffin suspects that changes in mu allowed atoms to disintegrate more quickly in the past, quickly enough to justify the Young Earth Hypothesis. As evidence, Chaffin notes that scientists in Europe did tentatively determine that the proton-electron mass constant has gotten smaller since the start of the universe, by a few thousands of a percent.
This was rapturous news and has invigorated the small field of creationist physics, partly because the scientific age of Earth, about 4.5-billion years old, derives from radioactive dating. Chaffin says, “I even run into laymen who aren’t scientists who get excited on these subjects.”
Unfortunately for creationists, the small fluctuations in constants measured so far cannot compress the universe nearly enough to meet biblical strictures. But in an odd, ironic way, the work of mainstream scientists on alpha and mu does link back to the creation story, or at least a creation story.
Work on fundamental constants will help scientists understand how universes work—how they’re born, and what makes a universe viable. If constants are constant, maybe they’re fixed at the only values they can possibly have. Perhaps only those values support life. On the other hand, if constants vary, especially if they vary a lot, then different universes might have existed. Perhaps a sort of Darwinian natural selection weeded some of them out (and might extinguish ours some day). Science would have the basis for a new field, comparative cosmology.
Either way, we’ll find out something amazing: that our universe with varying constants is stranger and more fluid than anyone realized; or else that it’s better built and sturdier than we ever imagined.
Sam Kean is associate editor of Search.
