Shining Light on Dark Energy
Fifteen years after cosmologists proposed the existence of dark energy, they have learned nothing about it.
In “Cosmology: Out of the Darkness,” Matthew Chalmers discussed the current thinking of Brian Schmidt, who shared the Nobel prize in 2011 for discovering cosmic acceleration (actually, an inference based on light from supernovae; see 9/30/2012). “Fifteen years after Schmidt’s initial discovery, the ‘dark energy’ invoked to explain this cosmic acceleration is still a mystery,” Chalmers began.
The dark energy proposal brought with it “the most sobering fact in physics,” Chalmers said: the thought that 96% of existence is something we cannot see or understand (dark energy, 73%, and dark matter, 23%); “their existence is inferred by the effect they have on ordinary matter, but their natures are unknown,” yet they are the primary ingredients of today’s “standard model” of cosmology. Some have hopes that dark matter will be detected some day, but dark energy represents “a new kind of bafflement,” he wrote. A cosmologist remarked, “You have no intuition or guidance because the physics is so different to anything we have experienced.”
Brian Schmidt studied the supernovae that led to this “crazy” conclusion. Before introducing Schmidt’s current views, Chalmers digressed into a brief history of the past decades offerings to explain dark energy: the cosmological constant, the multiverse, and some versions of the anthropic principle. This has left cosmologists at an impasse despite 7,500 papers with the phrase “dark energy” in the abstract. They are in need of a “big leap,” Schmidt said in a paragraph Chalmers entitled with Disney lingo, “Imagineering the universe.” This led into a digression about scalar fields and whether they exist or not, followed by this admission:
However, scalar fields are only one option. “There are hundreds if not thousands of possibilities,” says [Pedro] Ferreira [Oxford U]. Dark energy might be a vector field — one that has both a magnitude and a direction at each point in space. Other, wilder theories postulate higher dimensions of space. But Ferreira laments the overall lack of progress. “I don’t think that we’ve learned anything significant about dark energy since 1998.”
Yes, imagineering is a large, wild playground. Other cosmologists are beginning to wonder if dark energy is real or not. It could be an artifact of assumptions in the standard model: namely, that relativity holds throughout the universe, and that the universe is homogeneous and isotropic. “So far, both assumptions have been supported by observations, yet at distant regions of space they might break down.” One critic said, “We are in a mess with dark energy.” Another said, ““In terms of understanding the rhyme or reason of how it works, there have been many papers on dark energy but no breakthrough ideas.” Schmidt still defends the standard model, with the worry that “it requires us to invent 96% of the Universe.”
Chalmers spent the rest of the article hoping that new missions and techniques might someday find dark energy. He humorously suggested that astronomers had better hurry up, then ended on an anthropic note:
They need to seize the moment: if the expansion of the Universe is accelerating, then in a few tens of billions of years everything will have disappeared over the cosmic horizon and be too far away for its light to ever reach us. “We are losing information by the second,” says Schmidt. “The number of atoms that are in our horizon is dropping rapidly and has been for about 6 billion years, so it’s an interesting time that we live in.”
Indeed, why should humans exist at an “interesting time” when so much of the universe is still visible?
Believe it or not, this is not the only crazy idea in cosmology circles. PhysOrg reported on efforts to determine if our universe is real or a simulation. Matrix cult members might like to ponder that one. Could beings interior to a simulation ever know? The question seems to lead to an infinite regress, because the simulation could have planned for its inhabitants to ask the question.
The Surprise Theory of Everything
A saner look at cosmology was presented Oct. 15 by cosmologist Vlatko Vedral on New Scientist. Against a backdrop of 19th century work by Carnot, Clausius, Joule, Maxwell, Boltzmann and other physicists, he led up to the latest thinking about thermodynamics and information, which he calls a physical property of the universe. He then proposed that the Second Law of Thermodynamics – the law of entropy – could be the “surprise theory of everything” cosmologists seek.
The law of entropy survived both relativity and quantum mechanics, he said – the two biggest (even “absolute”) scientific revolutions if there ever were any. It explains time; it explains every possible action in the universe; and it will constrain any future theory of physics. Quantum uncertainty has filled in the concept of entropy and made the Second Law robust. Even gravity, Vedral argued, can be expressed as a consequence of the law of entropy. In “One theory to rule them all,” he concluded:
Take all this together, and we begin to have a hint of what makes thermodynamics so successful. The principles of thermodynamics are at their roots all to do with information theory. Information theory is simply an embodiment of how we interact with the universe – among other things, to construct theories to further our understanding of it. Thermodynamics is, in Einstein’s term, a “meta-theory”: one constructed from principles over and above the structure of any dynamical laws we devise to describe reality’s workings. In that sense we can argue that it is more fundamental than either quantum physics or general relativity.
Accept that and we can put “all our trust in the laws of thermodynamics,” he said. We can use thermodynamics to drive our theories forward. Since the law of entropy prohibits certain actions, and comports with our observations of nature, “The ultimately ‘correct’ theory of physics – the logically tightest – is the one from which the smallest deviation gives us something that breaks those taboos.” Time vanishes into the mix, becoming a consequence of allowed and disallowed processes.
On a roll now, Vedral got downright theological. In “God the Thermodynamicist” he said,
Such an approach would probably please Einstein, who once said: “What really interests me is whether God had any choice in the creation of the world.” A thermodynamically inspired formulation of physics might not answer that question directly, but leaves God with no choice but to be a thermodynamicist. That would be a singular accolade for those 19th-century masters of steam: that they stumbled upon the essence of the universe, entirely by accident. The triumph of thermodynamics would then be a revolution by stealth, 200 years in the making.
His article generated a lively stream of comments.
God is not constrained by His creation; as the transcendent Creator, He does as he pleases. Vedral’s article, though, even if it’s not the last word, made a lot more sense than the crazy ideas of materialists who force reality into their own evolutionary concepts and have to invent 96% of reality as something impervious to observation and reason. Mainly, Vedral’s “surprise theory of everything” comports with everything Drs. Henry Morris and Duane Gish used to argue in their debates against evolutionists: that the laws of thermodynamics (1) are universal, (2) are the best examples of laws of nature we have, and (3) prohibit evolution. The first law forbids any new matter or energy from entering the universe, and the second law ensures that all real processes run down, not up. That’s no surprise at all.
Before evolutionists get uptight about that generalization, Morris and Gish realized (as Vedral also explained), that local increases in complexity can be offset by entropy increases in the environment. That’s why a baby can grow into an adult, locally and temporarily–provided it is intelligently guided with a program and an energy conversion mechanism aimed to implement the program. Vedral enhanced the argument in terms of Maxwell’s Demon, a thought experiment set up to ask whether the second law could be overcome by a living or mechanical choice, adding that the choice being made is not just selection of hot or cold particles, but storage of information. He said,
An intelligent being can certainly rearrange things to lower the entropy of its environment. But to do this, it must first fill up its memory, gaining information as to how things are arranged in the first place. This acquired information must be encoded somewhere, presumably in the demon’s memory. When this memory is finally full, or the being dies or otherwise expires, it must be reset. Dumping all this stored, ordered information back into the environment increases entropy – and this entropy increase … will ultimately always be at least as large as the entropy reduction the demon originally achieved.
Since there are no known exceptions to the second law, it is the law that should guide what theories of origins we design. The universe itself had to begin in a state of incredibly, unfathomably low entropy, and run down from there. This implies high information content at the start. The source of information is intelligence. The intelligence could not be part of the cosmos (pantheism, panentheism or materialism), but had to transcend it and not be bound itself by the law of entropy. The only Being fitting that description is the Judeo-Christian God. Creation by God is, therefore, the best explanation for the cosmos, both theoretically and observationally. The vacuousness of the alternatives shown above only strengthens the case that “In the beginning, God created the heavens and the earth.” If Schmidt and Chalmers need a “big leap,” let them take this one – back to rationality.