Inflation Again: This Time with Feeling

Inflation is dead.  Long live inflation.

The cosmological inflation theory made Alan Guth famous back in 1981.  In case the enthralled didn’t get the message, it was a colossal failure, Amanda Gefter broke the news on New Scientist.  To set up Humpty Dumpty’s fall, she began with its seeming successes: “in one fell swoop,” it rescued big bang theory from the flatness problem and horizon problem  That was before cosmologists stopped admiring the “munificence” of inflation and starting thinking about its implications: it leads to nonsense:

The problem is that once inflation starts, it is nearly impossible to stop. Even in the tiny pre-inflation cosmos, quantum fluctuations ensured that the inflaton field had different energies in different places – a bit like a mountain having many balls balanced precariously at different heights. As each one starts rolling, it kicks off the inflation of a different region of space, which races away from the others at speeds above that of light. Because no influence may travel faster than light, these mini-universes become completely detached from one another. As the inflaton continues its headlong descent in each one, more and more bits of space begin to bud off to independent existences: an infinite “multiverse” of universes is formed…

This is not good news for our hopes for cosmic enlightenment. In a single universe, an underlying theory of physics might offer a prediction for how flat the universe should be, say, or for the value of dark energy, the mysterious entity that seems to be driving an accelerated expansion of the universe. Astronomers could then go out and test that prediction against observations. 

That’s not possible in an infinite multiverse: there are no definite predictions, only probabilities. Every conceivable value of dark energy or anything else will exist an infinite number of times among the infinite number of universes, and any universal theory of physics valid throughout the multiverse must reproduce all those values. That makes the odds of observing any particular value infinity divided by infinity: a nonsense that mathematicians call “undefined”.

Gefter quoted Max Tegmark of MIT who likened inflation theory to a charismatic guest who wore out his welcome and wouldn’t stop talking.  It sounded so good at first.  “”‘That would have been the perfect point for inflation to bow, wait for applause and exit stage left’,” says Tegmark. But that didn’t happen. Instead, inflation kept on predicting still more things – things that nobody wanted.”  Tegmark and others now agree inflation theory died:

“We thought that inflation predicted a smooth, flat universe,” says Paul Steinhardt of Princeton University, a pioneer of inflation who has become a vocal detractor.  “Instead, it predicts every possibility an infinite number of times. We’re back to square one.” Tegmark agrees: “Inflation has destroyed itself. It logically self-destructed.”  Sean Carroll was only a little less pessimistic.  “”Inflation is still the dominant paradigm,” he said, “but we’ve become a lot less convinced that it’s obviously true.”  By starting with such precisely balanced conditions, it explains less than the flukes it was intended to explain.  “”If you pick a universe out of a hat, it’s not going to be one that starts with inflation,” he said.

Brain Drain

Gefter took a brief tour into other cosmological theories that arose to replace inflation, such as brane theory: two 4-D projections of 5-D surfaces collided at perfect parallels, yielding a big-bang lookalike.  One benefit for those uncomfortable with a cosmic beginning is that it resurrects old hopes of a cyclic universe with an infinite past.  Any theory, though, that tries to explain special conditions (e.g., our universe) with even more special conditions fails to show the kind of scientific progress cosmologists prefer–simple beginnings leading to complex observations, a “theory of everything.”  Thus, a “brane drain,” as Gefter dubbed it  —

If nothing else, the cyclic model introduced some competition into the big bang market. “It shows that you’re not stuck with inflation – other ideas are possible,” says Steinhardt. “But whether or not you like this particular alternative is a matter of taste.“

Not everyone did. Models of the big bang that involve a singularity in our space-time, including the inflationary big bang, neatly excuse us from explaining what happened at the universe’s beginning: the singularity is a place where the universe falls off the cliff of existence and the laws of physics break down. But in the cyclic model, we must explain how the fifth dimension survives its momentary lapse into a singularity. “To me, it doesn’t seem to work,” says Thomas Hertog of the Catholic University of Leuven (KUL) in Belgium, who worked on the idea for a couple of years. “The calculations suggest that the transition through the singularity is very unlikely.“

The many clashes between branes that the model implies just compound the problem, says Carroll. “If you follow the cyclic universe backward in time, the conditions that you need become more and more special, or unlikely.“

No Boundaries

Next came the “No-Boundary Proposal” of Stephen Hawking and James Hartle, made famous in the former’s best seller, A Brief History of Time.  Gefter described it as a kind of “multiverse in reverse,” where Hawking and Hartle “added up all the possible histories that began in a universe with no boundary and ended in the universe we see today.”  Though some were initially attracted to the proposal because it seemed to get rid of a beginning to the universe, it hardly merited a couple of paragraphs in Gefter’s review: “That all sounds very neat, but there was still no reason to believe the no-boundary proposal was true. It was difficult to see where it fitted in to the sort of unifying theoretical constructs, such as string theory, which are needed to explain events in the early, high-energy days of the universe.”

Cosmic Combo Plate

Nothing seemed to work.  How about a combination?  Gefter tried to end on a cheerful note by suggesting that maybe a combination of inflation, string theory, the no-boundary proposal might serve up a universe that solves the problems inflation tried to solve without making things worse. Adding bad ideas together might seem another bad idea.  There had to be at least one new trial ingredient, and string theory served up the spaghetti:

That might just have changed, thanks to one of the most profound ideas to come out of string theory in recent years: the holographic principle. This states that the physics of a 4D universe such as ours, including gravity, is mathematically equivalent to the physics on its 3D boundary without gravity. The implication is that the world we see around us is nothing but a holographic projection of information from the edge of reality. It sounds implausible, but the principle pops up not just in string theory, but in almost any approach to unifying relativity and quantum theory dreamed up so far.

If this sounds bizarre, remember that in modern cosmology, bizarre is beautiful as long as it gets rid of intelligent design.  It may also sound like a stretch of desperation.  To Gefter and her cosmology protagonists, the Holographic Principle comes to the rescue of the No-Boundary Proposal, string theory and inflation in the nick of time.  One weird aspect of the idea she explained:

Although the no-boundary proposal says that the universe has no boundary in the far past, it does give a boundary in the infinitely far future. By calculating the physics on this boundary, Hertog extracted the probabilities of all the possible universes that can emerge as its holographic projections. Remarkably, the probabilities for things like the homogeneity of the cosmic background or the amount of dark energy are the same as those that you get from the no-boundary wave function. This supplies a direct connection between string theory, the most popular route towards a theory of everything, and the no-boundary proposal, which produces inflation naturally.

“Originally the no-boundary wave function was sort of picked out of thin air,” says Hertog. “But now we see that it lies at the heart of the holographic principle. This is very encouraging for inflation.“

Cosmologists are still “digesting” the combo plate, Gefter ended.  Some are “questioning whether the assumptions it makes are justified.”  Even Alan Guth, whose inflation theory the new proposal rescues somewhat, is not sure about the validity of its specific holographic correspondence, but is willing to give researchers time to play with it.  Gefter decked the halls of the holodeck with bows of jolly, hoping the Holographic Principle may bring back the doubters, like Tegmark, who consider inflation an imposter.  “We are not yet there, at the true story of the beginning of the universe,” she ended.  If we can consistently apply quantum mechanics to the fabric of the universe, we might get there.  “Only then will we truly know what kind of a bang the big bang was.”

At least secular cosmologists are in complete agreement on 3 things: the universe exists today, it originated in the past, and the explanation is in the future.

Cosmologist: a highly intelligent person, very gifted in mathematics, who devotes his life to rationalizing insane ideas.  If you think this is harsh, remember what Prophet Berman said 8 years ago? (10/06/2004).  Modern cosmologists are clueless, they’re right out of The Emperor’s New Clothes, and nothing they say is likely to be true.

For further proof, look at how their biggest ideas have all been undermined.  They are like white tourists in Fiji trying to do firewalking.  They dance from one hot rock to another in a kind of Brownian motion, grinning for a few milliseconds on each one before the pain is unbearable.

Learn an important lesson here.  Cosmologists and the press leapt onto inflation like flies to a carcass, so excited that the brilliant genius Alan Guth (Grand Unified Theory Huckster) saved the big bang from the Flatness Problem and the Horizon Problem.  “In one fell swoop,” Gefter reminded us, he saved the day.  Inflation was simple.  It was elegant.  It was beautiful.  It was wrong.  Tegmark likened it to the gift that keeps on giving till it got sickening, or like the performer that should have bowed out but kept giving encores nobody wanted, to the point they ran out of the theater screaming.

So they retreated to other irrationalities, like brane theory or the no-boundary proposal.  As with inflation, brane theory turned out to create more problems than it explained: it required even finer tuning than the fine-tuned universe we see.  As for Hawking & Hartle’s Hilarious Hoopla (4H) that proposed a no-beginning in a no-time fantasyland, remember it was a proposal, not a theory (proposal, n.:the act of offering or suggesting something for acceptance, adoption, or performance).  It was a suggestion they offered, like “try this.”  That’s not even a hypothesis yet.

So now, it’s back to inflation, with a combo plate of no boundaries, strings and The Holodeck.  We’re all like Lt. Commander Data wandering in an imaginary Holographic universe that is a projection of something real we cannot be sure is really there.  As usual with everything evolutionary, the answer is all futureware and promissory notes.  Why does anybody listen to these people?  It doesn’t matter if they can write equations all over the blackboard.  If the inputs to a “proposal” are bogus, no amount of mathematical manipulation can rescue a lie.

If you really want to see what’s motivating these folks, look at a slide show by Max Tegmark from a symposium, reproduced on Scribd.  The wiggle room in cosmology would make a mouse in a boxcar feel crowded.  Tegmark reasons himself into a multiverse with the flimsiest of arguments, all while struggling to defend his naturalism against the clear implications of our low-entropy universe.  “Sound too crazy?” one slide asks in large yellow print on a black background.  (This means he knows it’s crazy.  He’s like a lunatic asking you to take his word for it that he’s not crazy.)  But his justification for his craziness is seen on the very next slide: it’s a portrait of Charles Darwin, with the caption, “We’re not taking this guy seriously enough.”  What, you ask, has Darwin to do with a multiverse?  Ah, you see, this is all part of the Religion of the Bearded Buddha: try to explain everything from the bottom up without that despised, dreaded Designer.  Anything but that!– even irrationality.

We would direct your attention back a few slides in Tegmark’s show to a photograph of a group of sharp-looking college students wearing black T-shirts with red-and-white lettering.  Tegmark knows all about the symbols in white: those are Maxwell’s Equations, a set of four equations that James Clerk Maxwell, a Christian and creationist, derived to explain all electromagnetic phenomena.  The caption in red letters reads, “And God said,” [Maxwell’s Equations], “and there was light.” (See similar design close up here.)

We invite these highly intelligent but misguided individuals, lost in the dark, to come to the light.  It’s so much easier to work with proper lighting; much more satisfying, too.