Cosmologists in Search of Dark Ghosts
Dark matter and dark energy: do they exist? Cosmologists and physicists are spending large amounts of money building huge and expensive detectors to find them, but so far have found nothing. This raises profound questions about the limits of science, the interaction of observation with theory, the presuppositions behind scientific models, and the sociology of the scientific community. The universe, clearly, owes no obligation to scientific models; it is what it is. If scientists were to pursue a false path in their search for understanding, how long could they be wrong? For a thousand years?
Two articles in Nature explored the search for dark stuff. Jenny Hogan wrote about the search for dark matter,1 and Geoff Brumfiel wrote about the search for dark energy.2 In short, the dark matter search seems more promising than the dark energy search. “Jenny Hogan reports that attempts to identify the mysterious dark matter are on the verge of success,” The heading before the two articles reads. “In the second, Geoff Brumfiel asks why dark energy, hailed as a breakthrough when discovered a decade ago, is proving more frustrating than ever to the scientists who study it.”
Yet even Hogan’s dark-matter article contains some disturbing revelations. After describing large tanks of xenon and argon deep in European and American tunnels that hope to feel the bumps of passing dark matter particles, and the race to be the first scientist to detect them, she admitted, “Despite the enthusiasm, there is still a chance that nature will refuse to cooperate, and the experiments will chase ever better limits but never detect a particle.” Some of the feverish activity behind the search has the feel of a snipe hunt or ghostbusters escapade.
No one knows what dark matter is, but they know what it’s not. It’s not part of the ’standard model’ of physics that weaves together everything that is known about ordinary matter and its interactions. The standard model has been hugely successful, but it also has some problems, and in trying to fix these, theorists have predicted hordes of new fundamental particles. At first, these hypothetical particles were viewed as unwelcome additions, but now some of them are leading candidates for dark matter. “These days a theory without a dark-matter candidate is not considered an interesting one,” says [Leszek] Roszkowski [CERN]. “The existence of the dark-matter problem is perhaps the most convincing evidence for physics beyond the standard model.”
Could it be that the community of physicists has jumped on a fast-moving bandwagon going nowhere? They give names to theoretical entities: neutralinos, gravitinos, axions, and other things with exotic names, which might not even exist. The scientists talk about weakly-interacting massive particles, or WIMPs, and tell us that 10 billion of them pass through every square meter of the Earth every second – yet no instrument, no matter how sensitive, has ever detected one. Even the Large Hadron Collider at CERN, going into operation next year, will not be able to detect their presence with certainty: “Because such evidence is indirect, finding a WIMP signature at the LHC would not confirm it to be dark matter,” Hogan acknowledged.
Why, then, do theoretical physicists and cosmologists believe they exist? Part of the reason comes from observations dating from the 1930s that galaxy clusters seem too loosely bound gravitationally to keep from flying apart over billions of years. The belief also stems from physical theories about the nature of gravity and fundamental particles. Having elegant models and expensive instrumentation, however, cannot legitimize a belief that fails observational confirmation. But even if observations find a ghostly particle, don’t expect that there is only one kind of ghost. Hogan ended with this escape clause for the theorists:
Dark matter might prove to be a richer problem than anyone is expecting. [Max] Tegmark [MIT] hopes for this outcome. “This could be a wonderful surprise. It’s very arrogant of us humans to say that just because we can’t see it, there’s only one kind of dark matter.”
Critics might see this as job security for people with vivid imaginations. And that was the good news. Searchers for dark energy have even bigger problems.
Geoff Brumfiel’s article contains a strange mix of observation and theory. It is commonly reported that the universe is flying apart faster than cosmologists expected from the normal expansion of the universe – but that presupposes acceptance of inflationary big-bang cosmology. Inflation was invented to solve the flatness problem. Our universe is finely balanced between its density and expansion rate. Explaining this degree of fine tuning naturally has been a challenge for cosmologists for decades. Inflation seemed to solve it by positing a rapid, exponential expansion in the early stages of the big bang. Brumfiel wrote, “the expansion provided a way out of a theoretical impasse. Observations of the Big Bang’s afterglow made by various groups, including Bennett’s, indicated that the Universe’s gravity had flattened it out.”
As happens so often in science, a solution breeds new problems. There didn’t seem to be enough matter to have this effect on space-time. Enter dark energy: “it turned out that the amount of energy needed to drive the acceleration was pretty close to that needed to solve the flatness problem by means of its gravity,” he wrote. This created initial excitement in 1998 when evidence for an accelerating universe was announced. Dark energy, he said, seemed “poised to provide great insight into the origin and future of the cosmos.” Those hopes have been replaced by bigger problems:
But a decade further on, researchers seem to have swapped one theoretical conundrum for a bigger one. Follow-up measurements have revealed little about the nature of dark energy, and theories to explain it have failed to gain traction. And although astronomers are trudging forwards with a battery of new measurements, there is little guarantee that any will solve the problem – and thus no clear consensus on how much effort to put into them. “The issue is: how much information do we get from these future observations?” asks Avi Loeb, an astrophysicist at Harvard University.
The fine-tuning of the expansion has caused some, like Leonard Susskind (Stanford), to propose a nearly infinite “multiverse” in which our universe’s vacuum energy is just right to allow for stars and planets and life (see 12/18/2005, 01/04/2006, 08/11/2006). While others dislike the anthropic implications of this view, nothing better has been proposed that does not create more problems than it purports to solve:
This sort of anthropic argument irks many scientists. Critics say such reasoning is almost impossible to verify and doesn’t provide any deeper insight into the cosmos. “Anthropics and randomness don’t explain anything,” says Paul Steinhardt, a theorist at Princeton University in New Jersey. “I’m disappointed with what most theorists are willing to accept.”
The trouble is that no other approaches are proving any more fruitful. Some suggest that the problem lies with Einstein’s idea of gravity, which they then seek to modify in a way that fits in with dark energy. “It would be very fortunate if the dark energy were a modification of gravity,” says Georgi Dvali of New York University, “because it would address fundamental questions of physics.“ But others see little mileage in such changes. Leaving aside the cosmos, “it’s not so easy to get those theories to be consistent with our Solar System”, says [Michael] Turner [U of Chicago]…..
In general, the theoretical side of the debate is not a pretty thing. “We’ve tried a whole bunch of things and nothing has sprung forward,” says Sean Carroll, a theoretical physicist at the California Institute of Technology in Pasadena.
So how far can a cosmologist go before admitting defeat? As far as he wants. Secular cosmologists never want to give up and just say that “things are as they are because they were as they were,” as Thomas Gold once joked. The search for ultimate answers is part of the game. So the observationalists will continue to build huge detectors, trying to sharpen measurements that might nail down the ‘equation of state’ of the universe to finer degrees of precision, while the theoreticians, arguing that observations can only describe but not explain, will continue to theorize exotic particles. When the particle zoo gets too cumbersome again, a new, more fundamental theory will be erected with smaller, more abstruse building blocks.
No matter how frustrating or hopeless, no matter how far off course, the show must go on: this is the game of secular science. Being right is no fun. Exasperation is the angst that propels the game onward, right or wrong. Here is how Brumfiel ended his article:
For now, many in the field are left with a sense of unease: the tantalizing clue they thought they had discovered has turned into an exasperating mystery. And with no clear explanation of something that could be up to three-quarters of everything out there, it’s hard not to feel like you’re missing a big part of the picture, Susskind says. “We could be wrong about cosmology for the next thousand years. Deeply wrong.”
1Jenny Hogan, “Unseen Universe: Welcome to the dark side,” Nature 448, 240-245 (19 July 2007) | doi:10.1038/448240.
2Geoff Brumfiel, “Unseen Universe: A constant problem,” Nature 448, 245-248 (19 July 2007) | doi:10.1038/448245a.
They can’t even figure out our nearest star (the sun) and they want to tell us about the ultimate origins and fate of the universe – and even of multiple universes that would be beyond observation even if they existed. What unconscionable arrogance.
You know what the whole problem is? These people refuse, by choice (not because of the evidence), to acknowledge God in their thinking. Searching for answers is a noble undertaking, but if you throw away the key before you start, no one should feel sorry for you when you get lost.
The secular cosmology community will not acknowledge the Creator despite being dragged kicking and screaming to the anthropic principle (08/11/2006, 05/11/2006). They are determined to work out solutions to the universe by themselves, without recourse to the key to the problem. They have made this choice a priori, before even looking through a telescope or at the output of a particle accelerator. Materialism is so engrained, it has become an addiction. The pain of withdrawal now is unthinkable. A thousand years of being deeply wrong is preferable to kicking the habit. This is your tax dollars at work: keeping an elite community hooked on a fruitless addiction.
You can almost hear the irate comeback: “Well, what would you do? Dismantle all this equipment and just say God did it?” Of course not. First of all, though, it should be clear that open-ended searches for ghosts is not good scientific practice, nor is spending a thousand years being deeply wrong. Hopefully we can also agree that the public cannot be expected to pay for any and all quixotic pursuits scientists dream up.
The LHC and other megascience projects employ many thousands of people, and require many bright, highly-trained PhDs to design and operate. This alone, however, is not a justification. One could just as well imagine building parallel-universe detectors – or fairy detectors. Would job security for thousands justify such expenditures? How about a megaproject to dig a big hole, then fill it in again? We must think rightly about the uses of technology and the expected payback to the people who pay for it. There has to be some relationship between the investment and the expectation of success.
There is value in pure research. A Murphyism states, “When you are investigating the unknown, you do not know what you will find.” Perhaps some useful fact will come out of dark-matter detectors that will improve our lives. If the goal is only to keep scientists busy, though, or to rationalize a materialistic philosophy, then the proponents should engage their hobbies on their own time and dime.
So what do we do with the LHC and the dark-matter detectors, the WMAPs and other such projects? We change the presuppositions. We start with the presupposition that there is a Creator who has revealed Himself in His creation. This is the presupposition that motivated the great founders of science. Our efforts, then, are directed once again at “thinking God’s thoughts after Him” to understand how He ordered the world and the universe and life. And, as Francis Bacon admonished, we gear our efforts for the betterment of mankind. These two goals can justify large expenditures on elaborate projects. This is a far cry from today’s elitist mindset that misuses science to eliminate all thoughts of God and thinks the public should give scientists anything they want just because they are curious about the latest unverifiable, materialist fad.
How ironic that the secularists should end up in quixotic pursuits after imaginary entities. Their refusal to admit in their thinking a Holy Ghost who hovered over the surface of the waters at Creation did not free them from the need for ghosts. They had to invent their own so that they could search endlessly for them. What else can a soul do to alleviate the pain of denying its own existence?