BICEP2 Study Has Not Confirmed Cosmic Inflation

The BICEP2 study was released yesterday, and found some evidence of something called b-mode polarization in the early universe. Advocates of the theory of cosmic inflation were quick to trumpet these results, with many of them claiming that the study had finally confirmed the theory of cosmic inflation. This theory maintains that the universe underwent a period of exponential inflation during a fraction of its first second.

But there are several reasons why the BICEP2 study does not confirm cosmic inflation or even provide substantial evidence for it.

The first reason is that a single scientific study rarely proves anything. Having followed scientific developments closely for more than four decades, I have lived through many a case of scientific announcements that did not stand the test of time. I remember back around 1980 an announcement in which scientists announced a fate for the universe (collapse) that is the exact opposite of the fate they now predict for it (unending expansion). I also remember the famous “life on Mars” announcement in the 1990's which did not pan out. At this web site a scientist says that there is only a 50% chance that the results from this BICEP2 study will hold.

Another reason for doubting this BICEP2 study is that it makes an estimate for an important cosmological ratio called the tensor-to-scalar ratio, and that estimate is about twice the maximum possible value, according to the estimate from a very definitive source on the topic, the Planck team of scientists (larger than the BICEP group). Apparently some group of scientists are in serious error in regard to this matter, and there is a 50% chance that it is the team that made yesterday's BICEP2 study. If they are the ones who are wrong, it throws much of their study into doubt.

A third reason why the BICEP2 study does not confirm the theory of cosmic inflation is that BICEP2's results do not match well with the predictions of that theory.

The supporters of the inflation theory are citing the graph below from the BICEP2 study. The black dots are the BICEP2 observations, with the vertical lines being error bars (representing uncertainty in the data). The bottom red dashed line is what we expect from the cosmic inflation theory.

Considering just what is predicted from the theory of cosmic inflation, the results do not match well at all. The little black dots show a rise in the line exactly where the cosmic inflation theory predicts a fall in the line.

To patch up this embarrassing discrepancy, the authors add a “gravitational lensing” factor, which seems like quite the little fudge factor. Gravitational lensing is a very exotic effect that is not an easy thing to predict or nail down with any certainty. Estimating the amount of gravitational lensing that occurred long ago is like estimating the total tonnage of asteroids that have struck in the past billion years – very much a type of estimate that involves a huge amount of uncertainty. The BICEP2 authors seem to have got an estimate for gravitational lensing by making inputs to a 3-year old computer program called LensPix. There are lots of ways to go wrong there, either in the inputs or in the software (and the site for the software says “there are almost certainly bugs” in this software).

What is interesting, however, is that even if you accept as gospel truth this estimate of the amount of gravitational lensing, the data from BICEP2 ends up strongly diverging from the expected results produced from the estimated amount of gravitational lensing and cosmic inflation.

It is very hard to tell how big this discrepancy is from the graph shown above, because it uses two sneaky data presentation techniques to make the discrepancy look much smaller than it is. The techniques are: (1) the graph unnecessarily includes a whole load of irrelevant data in the top half of the graph, causing the scale of the graph to be unnecessarily large; (2) the graph uses a logarithmic scale (a type of scale that often tends to make two data items look closer than they are).

I can use exactly the same techniques to make a graph that makes it look like a dishwasher makes almost the same amount of money as a Wall Street bond trader.

But, thankfully, buried within the BICEP2 scientific paper is a nice simple non-logarithmic graph that shows just how great the difference is between the BICEP2 results and the results predicted from the cosmic inflation theory. The graph is below.

In the graph above the black dots are the new BICEP2 observations. The vertical lines are uncertainties in the data. The bottom red dotted line is the prediction from the theory of cosmic inflation. The solid red line is the estimated gravitational lensing factor. The upper red dashed line is the result predicted given a combination of the gravitational lensing factor and the theory of cosmic inflation.

Notice the big difference between the observed results and the expected result. Even if we include this highly uncertain gravitational lensing fudge factor, the predicted results from the cosmic inflation theory do not closely match the observed results. Note that the sixth and seventh black dots are way above the top dashed red line.

Therefore these results are far from being a confirmation of the theory of cosmic inflation. They can't even be called good evidence for cosmic inflation.

I may also note that there are numerous non-inflationary cosmological models that might produce the type of polarization observations that BICEP2 has produced. If there is currently a shortage of such models, it is largely because cosmic inflation speculations have almost monopolized the activities of theoretical cosmologists during recent decades.

The BICEP2 observations can be explained by the decay of exotic particles, or by some noninflationary exotic phase transition. Or it could be that all of the observed effect is produced by gravitational lensing and none of it produced by cosmic inflation. Scientists are already assuming that most of the observed effect is being produced by gravitational lensing; it's a short jump from “most” to “all” (particularly given the many uncertainties involved in estimating the amount of gravitational lensing).

If cosmologists spend as much time producing non-exponential non-inflationary models of the early universe as they do producing models that involve inflationary exponential expansion, they will probably find that non-exponential non-inflationary models are able to explain the observed BICEP2 results just as well, and perhaps even better.

Because the effect observed by the BICEP2 study can be produced by gravitational lensing, and because we will for many decades be highly uncertain about how much gravitational lensing has occurred in the past, it is very doubtful that any study like the BICEP2 will ever be able to provide real evidence for a theory of cosmic inflation. Just as UFO photographs rarely prove anything (because there are so many ways in which lights in the sky can be produced), a study like BICEP2 doesn't prove cosmic inflation (because there are other ways, such as gravitational lensing, that the observed polarization effect can be produced).

The case for the theory of cosmic inflation theory is much weaker than many think. In a nutshell the standard sales pitch for the theory is that it solves two cosmological problems: one called the flatness problem and the other called the horizon problem. The flatness problem is an apparent case of cosmic fine-tuning, and the horizon problem is an example of cosmic uniformity. The weakness in trying to solve these problems with a theory of cosmic inflation is that we have many other apparent cases of cosmic fine-tuning and many other cases of astonishing cosmic uniformity (including laws of nature and constants that are uniform throughout the universe). Inflation theory claims to solve only one of these many cases of apparent cosmic fine-tuning, and only one of the many cases of cosmic uniformity. That puts it in not a very good position, rather like a theory of the origin of species that only explains the origin of lions and tigers without explaining the origin of any other animals. I will explain this point more fully in a later blog post.

What is particularly ironic is that the theory of cosmic inflation claims to help in getting rid of some cosmic fine-tuning, but the theory itself requires abundant fine-tuning of its own to work, as many parameters in the theory have to be adjusted in just the right way to get a universe that starts exponentially inflating and stops inflating in a way that matches observations. 

Postscript: The chart below (in which I have added a green line) shows one way we can explain the BICEP2 observations without requiring any cosmic inflation.  We simply imagine a slightly higher amount of gravitational lensing (shown in the green line). The shape of this line matches the shape of the gravitational lensing estimated by the BICEP2 study (solid red line). Because the green line passes through all of the vertical error bars, it is consistent with the BICEP2 observations. 

BICEP2 graph with an added trend line (green)

Post-postscript: at this link cosmologist Neil Turok says, "I believe that if both Planck and the new results agree, then together they would give substantial evidence against inflation!"

Post-post-postscript: See the post here for a discussion of wishful thinking and cherry picking involved in the main graph shown above.   

Post-post-post-postscript: See this link for a National Geographic story on how the BICEP2 results may be caused by dust, not cosmic inflation. 

Yet another postscript: see this post for a discussion of a talk at Princeton University in which a scientist gives a presentation that gives a devastating blow to the inflated claims of the BICEP2 study. The scientist gives projections of dust and gravitational lensing which show how such common phenomena (not from the Big Bang or cosmic inflation) can explain the BICEP2 observations.  

Yet another postscript: In this article in the scientific journal Nature, it is explained that two recent scientific papers have concluded that there is no significant evidence the BICEP2 signals are from cosmic inflation or gravitational waves, with dust and cosmological lensing being an equally plausible explanation.

Teenage World Savior: A Science Fiction Story

All attempts to defeat the hostile extraterrestrial invasion had failed utterly. A meeting of military officers was convened at the house of Jonas MacDonald, a physicist who specialized in high-energy physics. The officers were there to ask the physicist if he knew of any high-tech way that the invading extraterrestrials could be attacked, perhaps with something such as lasers or electromagnetic pulse weapons.

“So far our military efforts have been a complete disaster,” said General Curtis. “After the aliens landed in New Jersey, and wiped out many people, we've hit them with every conventional weapon we had. We've dropped countless bombs. We've strafed them with our jets again and again. We've shelled the hell out of them with our best artillery. But we're getting nowhere. The alien stronghold keeps growing larger and larger.”

“Why aren't such attacks working?” asked MacDonald.

“They seem to have some kind of strange energy bubble around their landing area,” explained Curtis. “It's some kind of super-strong energy field that is able to vaporize incoming bombs and bullets. Whenever we shoot something at the alien stronghold, our bombs and bullets just kind of melt as soon as they touch the protective energy bubble.”

“Have you thought about using nuclear weapons?” asked MacDonald.

“No, that's out of the question,” explained General Curtis. “The prevailing winds would cause radioactive fallout to drift on to New York City.”

“Do you have a picture of what these extraterrestrials look like?” asked MacDonald.

General Wheeler produced a photograph, and put a picture on the table.

“Let me think,” said MacDonald. “There might be some kind of high-energy proton beam we could use to attack these things.”

MacDonald's 13-year-old son Artie walked into the room. Artie should have been at school, but he had got suspended for starting a big food fight in his high school cafeteria.

“Is that what the aliens look like?” asked Artie. “Cool.”

“This meeting is classified,” said MacDonald. “Artie, clear out of here.”

The men continued to discuss MacDonald's ideas for a high-energy proton beam. Twenty minutes later Artie came back into the room.

“Dad, I know I'm not supposed to be here,” said Artie. “But I've got an idea. I've got an idea about how you might defeat the aliens.”

“Artie, have you lost your senses?” asked MacDonald. “Nobody wants to hear a teenager's ideas on saving the world from an alien invasion.”

“But, Dad, it's a really good idea,” said Artie.

“Let the boy speak,” said General Curtis. “Right now, we're desperate for new ideas.”

“I got the idea from the cafeteria food fight I got suspended for,” said Artie. “We can fight the aliens with food.”

“Very funny,” said MacDonald. “Now go to your room, and don't bother us again.”

“I'm not kidding, Dad,” said Artie. “There's a way to do it. Look at that picture of the alien. He has no real nose. Just a kind of a slit for a nose. So my guess is these aliens are probably sensitive to particles in the air. If we bombard them with fine particles, it may kill them. The easiest way to bombard them with fine particles is by using spices.”

“Spices of what type?” asked General Wheeler.

“Any type of spice that is a very fine powder,” explained Artie. “Cinnamon or curry powder would probably do the job.”

“That's the craziest idea I've ever heard,” said MacDonald. “The aliens are protected by an energy bubble that would make it so that the powder couldn't even fall into the alien stronghold.”

“But it just might work,” said General Wheeler. “Who knows – maybe their protective energy bubble was only designed for things like bombs and bullets. Maybe a fine powder could get through that thing. Let's give it a try.”

So the conventional high-explosive bombs were taken out of a military jet. Two giant vats of cinnamon and curry powder were loaded into the jet. The jet made a bombing run of the alien stronghold, dumping the curry powder and cinnamon on to the strange alien structures.

The protective energy bubble of the aliens had been designed to destroy only incoming objects larger than about a millimeter. The curry powder and cinnamon fell right through the protective bubble.

The aliens breathed in the curry powder and cinnamon, and all died instantly. They came from a dustless planet, and had never evolved any apparatus for protecting their lungs from fine particles.

And so the teenage boy who had started a food fight at his high school cafeteria became known as the unlikely world savior who started a food fight that saved planet Earth.

The Lesson From Arthur C. Clarke's Predictive Errors

The television show Prophets of Science Fiction liked to portray science fiction writers as latter-day visionaries with great predictive powers. One of the writers profiled on this show was the late Arthur C. Clarke. Clarke was both a science fiction writer and a nonfiction writer who wrote about space exploration and the future. I greatly enjoyed his work, particularly when I was a teenager. Clarke first proposed communication satellites, and made some very prescient predictions about that technology.

Clarke's predictions about the immediate effects of space travel varied in accuracy. Clarke predicted that an age of manned space exploration would produce a new Renaissance, and judging from this argument the 1970's (directly following the 1969 moon landing) should have been a decade of immortal art. Anyone who remembers the music and television shows of the 1970's may chuckle at that concept.

But what about Clarke's record in making predictions about our century -- how accurate was he?

If fiction can be taken as a form of prediction, Clarke's record in regard to predicting our century was not very good. His most famous fictional work (co-authored with director Stanley Kubrick) was the screenplay for 2001: A Space Odyssey. Although it was a great artistic success (and one of my favorite movies), that movie predicted that the year 2001 would see a manned mission to Jupiter, a giant-sized lunar colony housing more than 100 residents, computers that could have conversations with a human and understand our language, and a giant space station with artificial gravity and very roomy interiors. None of those things actually occurred by 2001. It is now 2014, and no one is living on the moon. We haven't even made it to Mars, and probably won't get there for many years. Although there are “chat bot” computer programs that might fool you (for a while) into thinking you're talking with some one, there is no computer that even has the intelligence of a 1-year-old. The only space station is a small station in which a few astronauts live in cramped conditions, without artificial gravity.

 The Roomy Space Station in 2001: A Space Odyssey

But what about Clarke's nonfiction predictions about our century – how well do they hold up? In 1999 Clarke wrote for the London Sunday Telegraph an article called “The Twenty-First Century: A (Very) Brief History.” Below are some of the predictions he made, along with comments about their accuracy.

Clarke predicted that the year 2002 would see “the first commercial device producing clean, safe power by low-temperature nuclear reactions,” causing the inventors of cold fusion to get a Nobel Prize in physics in that year. Serious misfire.

Clarke predicted that the year 2004 would see the first example of a human clone. Misfire.

Clarke predicted that the year 2005 would see the first return of a soil sample from Mars. Misfire.

Clarke predicted that in the year 2006 the last coal mine would be closed. Very serious misfire.

Clarke predicted that in the year 2009 (because of a nuclear accident) all nuclear weapons would be destroyed. Serious misfire.

Clarke predicted that in the year 2010 “quantum generators (tapping space energy)” would be deployed, and that electronic monitoring would all but eliminate professional criminals from society. Both predictions were complete misfires.

Clarke predicted that in the year 2011 a space probe to Jupiter's moon Europa would discover life on that moon. Misfire.

Clarke predicted that in the year 2014 construction of a Hilton Orbiter Hotel would begin. Misfire.

These misfires are not hand-picked from a list of predictions including quite a few successes. As far as I can tell from his 1999 forecast , pretty much nothing that Clarke predicted to happen between the year 2000 and 2014 actually happened (except for the arrival of a space probe to Saturn, which was already due to arrive in the year Clarke predicted).

These predictions were from one of the twentieth century's leading futurists, who had written a widely-read book entitled Profiles of the Future. My purpose here is not to belittle Clarke, who I regard highly. My purpose is merely to suggest the lesson that no matter how highly regarded a particular futurist may be, you should remember that his predictions are just educated guesses.

So the next time you see Ray Kurzweil predict that highly intelligent computers are just around the corner, take it with a grain of salt.

You should also pay very little attention to the prediction in today's news, from the SETI Institute's senior astronomer Seth Shostak. Shostak predicts that if intelligent life exists in space, we will find it within twenty years. Although there is every reason to suspect that there is very much intelligent life outside of our planet, there is fairly little reason to conclude that if it exists we will find it in twenty years.Whatever reasons have prevented us from finding such intelligent life for the past fifty years may well also prevent us from finding it in the next fifty years.

Bouncing Black Holes May Cause the Sun to Suddenly Vanish

The sun has been shining for billions of years, and scientists say that in all probability it will continue shining brightly for billions of additional years. We assume that there is 100% probability that the sun will continue to shine throughout our lifetimes. But surprisingly enough, there is a very small chance that the sun will suddenly disappear at any time -- perhaps a thousand years from now, perhaps ten years from now, or perhaps even tomorrow.

The sun might vanish at any time because there is a very small chance that a particular theory I will now describe is true. If this theory is true, the sun might instantly disappear at any time.

The theory I mention is a theory involving black hole collapses. To explain that theory, I must first discuss why scientists think that black holes are formed. Scientists say that black holes are formed when very massive stars begin to collapse, with the collapse being caused by the enormous gravity of the star. A star that is more than five times more massive than the sun has a tremendous gravity many times higher than the gravity of our planet. But such a star emits lots of energy through thermonuclear fusion, and that causes an outward force that balances the inward force caused by the star's gravity.

But when the star nears the end of its lifetime and runs out of hydrogen and usable helium to burn as nuclear fuel, then there is no longer any outward force to counteract the force of gravity. The star's enormous gravity causes the star to suddenly shrink in size. Gravity crushes the mass of the star in a mighty collapse. Scientists think this causes a supernova explosion, along with the formation of a black hole. Much of the star's mass is blasted off into space, but the remaining mass then collapses into a state of infinite density called a black hole.

What happens to all that matter once this black hole forms? This is a matter for speculation; no one knows for sure. There are many exotic speculations. One speculation advanced by more than one scientist is that when black holes are formed, they create a spacetime wormhole. The idea is that the matter lost in a black hole travels through a wormhole, and then suddenly appears elsewhere in the universe. Such a sudden appearance has been called a white hole. Of course, this idea is pure speculation, and there is no evidence for white holes. But let us consider what the consequences might be if white holes were to be created from the creation of a black hole.

If a white hole were to be created, one possibility is that we might suddenly see a gushing of matter coming out from some point in space, perhaps some point in interstellar space. But we've never observed anything like that happening. So let's consider another possibility.

Another possibility is that once a white hole is created from a black hole, the white hole then immediately collapses to become a black hole again. This would make sense from a gravitational standpoint. Imagine if a star of 10 solar masses were to collapse, causing 7 solar masses to collapse into a black hole. That might cause the appearance of a white hole elsewhere in the universe. But an instant after that white hole appeared, you would then have 7 solar masses suddenly existing in some small area. Gravity would then probably cause all that matter to collapse in a process similar to the process that produced the original black hole.

We are led, then, to a fascinating possibility – the possibility of “ever-bouncing” black holes. The creation of a black hole might be the beginning of a process that works like this:

1. A super-massive star collapses to become a black hole.
   
2. The black-hole creates a spacetime wormhole, which causes the appearance of a white hole somewhere else in the universe, as the mass from the star collapse reappears elsewhere.
   
3. The matter coming from that white hole is so dense and concentrated that it very soon collapses to become another black hole.
   
4. That black-hole creates a spacetime wormhole, which causes the appearance of a white hole somewhere else in the universe.
   
5. These steps keep repeating over and over again endlessly, ad infinitum, forever and ever.
   

Theory of ever-bouncing black holes

Because many black holes have been created in the history of the universe, if this “ever-bouncing” black hole theory is true, then white holes could be appearing at various points in the universe millions of times every second. 

At this point the reader may well be thinking: well, that's a fascinating idea, but it is no reason for thinking that the sun may suddenly vanish – because the sun is not a supermassive star of the type that becomes a black hole.

It is true that the sun will never become a black hole purely because of its own gravity. But if this wild theory of “ever-bouncing” black holes is correct, then the sun still might be in danger. This is because when a white hole appears from the creation of a black hole, the white hole could randomly appear within the volume of the sun.

If we assume that a white hole appears at a random position in space, it is overwhelmingly likely that the white hole would appear in interstellar space, the space between stars. But there is a very small but nonzero chance that the white hole could appear in the worst possible place – right in the very volume of space that the sun occupies. Who knows, there could be some strange relativistic reason why a white hole is more likely to appear where there is already matter, perhaps something along the lines of matter being attracted to matter.

If such a white hole were to suddenly appear within the volume of the sun, it would be as if the sun were to suddenly acquire a mass many times greater. Most of that mass would be material that could not be used for nuclear fusion. So rather than suddenly becoming much brighter, the sun would suddenly be like a super-massive star at the end of its lifetime, about to collapse into the super-density of a black hole. Shortly thereafter, the sun would presumably collapse to become a black hole. There might or might not be the flash of a supernova explosion. Then the sun would vanish.

Imagine what it would like for you if this were to happen. You might go to work one day at the office. Then in the middle of the day, people would suddenly start shouting, as they noticed that it was inexplicably dark outside. Some people would say: “Wow, I didn't know there was a total eclipse today.” People would wait for the supposed eclipse to end. But the sunlight would never return.

People would gradually realize that the sun was gone forever. There would then be a desperate struggle, as everyone tried to gather up food, clothing, and generators that might allow them to survive as long as possible in the cold. It would soon become colder than the North Pole. Crops would stop growing. Remnants of the human race would probably be able to survive for a few months longer until the food and fuel ran out. A few lucky ones might even be able to survive for a few years.

Of course, the chance of this happening is extremely remote, but it is interesting to realize that there are theoretical reasons why the sun might suddenly vanish at any time. I don't know what effect such speculation has on you, but I, for one, am going to take serious measures to protect myself from this theoretical cosmic menace.

I am going to go out right now and buy myself a nice pair of wool mittens.