Occam’s Razor And Malaysia Airlines Flight 370

Share

Who knows, at this point, just what happened to Malaysia Airlines Flight 370? Only one thing seems clear as the media has ascended to ever-higher flights of fancy about it: no one seems to want to ruin a good yarn by promoting the simplest available hypothesis (as Occam’s razor would prescribe), no one, that is, except Chris Goodfellow in this Wired post-

The left turn is the key here. Zaharie Ahmad Shah was a very experienced senior captain with 18,000 hours of flight time. We old pilots were drilled to know what is the closest airport of safe harbor while in cruise. Airports behind us, airports abeam us, and airports ahead of us. They’re always in our head. Always. If something happens, you don’t want to be thinking about what are you going to do–you already know what you are going to do. When I saw that left turn with a direct heading, I instinctively knew he was heading for an airport. He was taking a direct route to Palau Langkawi, a 13,000-foot airstrip with an approach over water and no obstacles. The captain did not turn back to Kuala Lampur because he knew he had 8,000-foot ridges to cross. He knew the terrain was friendlier toward Langkawi, which also was closer.

For me, the loss of transponders and communications makes perfect sense in a fire. And there most likely was an electrical fire. In the case of a fire, the first response is to pull the main busses and restore circuits one by one until you have isolated the bad one. If they pulled the busses, the plane would go silent. It probably was a serious event and the flight crew was occupied with controlling the plane and trying to fight the fire. Aviate, navigate, and lastly, communicate is the mantra in such situations.

What I think happened is the flight crew was overcome by smoke and the plane continued on the heading, probably on George (autopilot), until it ran out of fuel or the fire destroyed the control surfaces and it crashed. You will find it along that route–looking elsewhere is pointless.

If you’re curious about the details of this relatively reasonable hypothesis, read the whole story.

Fun With Frax

Share

If you own an iPhone or an iPad and have ever had the urge to release your inner graphic artist… the one you’ve kept hidden since you were 5 years old and discovered you couldn’t draw worth s#*t… then you absolutely must shell out a whopping $2 and download a copy of Frax, the amazing little iOS app that allows you to create an infinite variety of fractal images using gestures, tilt, and a few simple controls. Once created, you can save your masterpieces to your photo library, or upload them to the Frax Cloud and have them rendered in ultra-high, poster-sized resolution.

Here’s an image I created in about five minutes, just trying to learn how to use the app (which has very helpful instructions embedded into it). To see what people who actually know what they’re doing with the app can come up with, check out the gallery at the Frax site.

First Try With Frax

President Obama’s Climate Change Speech

Share

Amazingly, at least in my neck of the woods, only one cable news network covered President Obama’s full speech on climate change policy today: Fox Business, which immediately followed it with an interview of an electric company executive who is investing heavily in coal. Interestingly, even he had to be goaded by the hosts into criticizing the policies outlined in the speech. The other cable news providers, even MSNBC, had other stories that they deemed more important. So I’m linking to a video of the speech here, and I would urge everyone who has heard about it only second-hand to watch it. Although it’s not one of Obama’s best-delivered speeches, what with the heat in D.C. today (not a bad way of setting the scene, given the speech’s topic), the policies outlined in it are significant.

The President’s failure in the past to act more decisively and to speak more explicitly on the climate problem has disappointed me. I’m no longer disappointed.

Are You A Boltzmann Brain?

Share

If you’re a Boltzmann brain, then I’m likely a figment of your imagination as you float around in otherwise empty (or at least high-entropy) space, a minimum assemblage of whatever matter or energy is required to generate your thoughts and images. You emerged as a “quantum fluctuation” of particles out of the quantum fields that underlie space itself – your mother was the vacuum (no offense intended). Yes, you were an unlikely fluctuation, but given enough time – and an eternity is more than enough time – you were bound to happen at some point. In fact, at least absent assumptions far more speculative and untested than those of statistical mechanics and quantum physics, it was far more likely that you would emerge as an isolated brain – or whatever assemblage of particles you really are – in infinite space than that the Big Bang would have occurred with just the right properties to give rise to the universe as we observe it.

The idea that you could be mistaken about everything except the fact of your own bare existence as a conscious mind is nothing new. In his Meditations, Descartes developed such a scenario on his way convincing himself that his own mind certainly existed, and hence (along with several controversial assumptions) that a benevolent, omnipotent God must exist, and therefore that our everyday beliefs about the physical world are highly likely to be true (as long as we form them carefully). To make his skeptical scenario psychologically vivid and a worthy antagonist to defeat, Descartes imagined that a malevolent demon might be deceiving him in every possible way. Of course, Descartes recognized that his demon scenario was utterly improbable, but since in his view knowledge had to be built on an absolutely certain foundation, he thought that the mere possibility of such a demon could undermine his previously uncritical faith in his common sense beliefs, and that showing that such a demon could not cause him to reasonably doubt his own existence would go a long way towards establishing a firm foundation for math, physics, and the other sciences. Critics, of course, love to point out that a mere possibility is insufficient to justify a reasonable doubt. It is possible that a mountain of gold will soon emerge in my back yard, but that mere possibility gives me no reason to doubt that I shouldn’t quit my day job just yet. The possibility of a demon similarly can provide no reasonable ground for doubting my common sense beliefs. By contrast, the disturbing aspect of the Boltzmann brain scenario is that our best-tested physical theories actually suggest that being a Boltzmann brain is not only possible, it’s actually more likely – much more likely – than the situation in which we believe ourselves to be.

To explain why we observe a relatively orderly, amenable universe around us, even though a higher-entropy, less amenable sort of universe is far more likely to emerge from the cosmos on purely statistical grounds, we naturalists often appeal to an “anthropic principle”: in an infinite universe, some regions are likely to be more amenable to life than others, and life will quite predictably exist only in those regions where its evolution is possible. But the statistical reasoning that supports the probability of your being a Boltzmann brain also undercuts such appeals to anthropic principles. Sean Carroll puts this nicely in his book, “From Eternity To Here”-

… Maybe, we might reason [in accordance with an anthropic principle], in order for an advanced scientific civilization such as ours to arise, we require a “support system” in the form of an entire universe filled with stars and galaxies, originating in some sort of super-low-entropy early condition. Maybe that could explain why we find such a profligate universe around us.

No. Here is how the game should be played: You tell me the particular thing you insist must exist in the universe, for anthropic reasons. A solar system, a planet, a particular ecosystem, … whatever you like. And then we ask, “Given that requirement, what is the most likely state of the rest of the universe [given statistical mechanics and quantum theory], in addition to the particular thing we are asking for?”

And the answer is always the same: The most likely state of the rest of the universe is to be in equilibrium. If we ask, “What is the most likely way for an infinite box of gas in equilibrium to fluctuate into a state containing a pumpkin pie?,” the answer is “By fluctuating into a state that consists of a pumpkin pie floating by itself in an otherwise homogeneous box of gas.” Adding anything else to the picture, either in space or in time – an oven, a baker, a previously existing pumpkin patch – only makes the scenario less likely, because the entropy would have to dip lower to make that happen.

It’s important to emphasize that Carroll’s point here isn’t to argue that we should in fact believe that we are Boltzmann brains, but rather to provide a sort of reductio ad absurdum of the limited set of assumptions and theories that lead us to that conclusion. Still, upon finishing Carroll’s book, which avoids the Boltzmann brain conclusion only by indulging in some extremely tentative cosmological speculations, it’s hard to simply dismiss the possibility that we are, in fact, Boltzmann brains.

Is Mitt Romney A Probability Wave?

Share

From David Javerbaum’s amusing opinion piece in last Sunday’s New York Times, entitled “A Quantum Theory of Mitt Romney“-

Before Mitt Romney, those seeking the presidency operated under the laws of so-called classical politics, laws still followed by traditional campaigners like Newt Gingrich. Under these Newtonian principles, a candidate’s position on an issue tends to stay at rest until an outside force — the Tea Party, say, or a six-figure credit line at Tiffany — compels him to alter his stance, at a speed commensurate with the size of the force (usually large) and in inverse proportion to the depth of his beliefs (invariably negligible). This alteration, framed as a positive by the candidate, then provokes an equal but opposite reaction among his rivals.

But the Romney candidacy represents literally a quantum leap forward. It is governed by rules that are bizarre and appear to go against everyday experience and common sense. To be honest, even people like Mr. Fehrnstrom who are experts in Mitt Romney’s reality, or “Romneality,” seem bewildered by its implications; and any person who tells you he or she truly “understands” Mitt Romney is either lying or a corporation.

Javerbaum goes on to argue (in an admirably concise and facile way) that Romneality illustrates all of the major concepts of quantum theory: complementarity, probability, uncertainty, entanglement, noncausality, and duality. Read it for yourself, and marvel at Mitt Romney’s phenomenal awesomeness!

(Thanks Nathan).

Thinking While Driving

Share

According to a story today in USA Today, talking or texting on a cell phone isn’t the only way to endanger yourself and others on the road. Concentrated thinking about anything causes similar distraction, at least if these researchers are correct-

The group, led by Bryan Reimer, a research scientist at MIT’s AgeLab, found that a driver’s ability to focus on the driving environment varies depending on the “cognitive demand” of a non-driving activity. That is, the deeper the level of thought in a driver’s mind, the less he focuses on his surroundings.

Good drivers routinely scan the road ahead and around them, looking for potential hazards that they might need to react to. When drivers face even light levels of cognitive demand, they scan the road less, Reimer says.

“In the past, the emphasis was on whether you’re distracted or not distracted,” he says. “This is too simple of a categorization. There are levels of cognitive demand, and those levels are statistically distinguishable.

“The level of thought going on has a relationship to how much a driver is aware of the driving environment,” he says.

Thinking while driving: there should be a law against it. Maybe when a cop pulls you over, the first thing he or she should look for isn’t an open container, but an open book (or an audio book), or any other tell-tale trace of thoughtfulness. College professors, of course, should be immediately suspect.

Living In The Anthropocene Era

Share

Given the dim-witted ignorance of science currently being manifested by prominent Republicans (from Rick Santorum’s cynical climate-change denial to Rush Limbaugh’s obvious misconceptions of how the birth control pill works), it was refreshing to read a story this week in a magazine as popular as Time outlining very concisely the influence billions of human beings are having on the natural world-

For a species that has been around for less than 1% of 1% of the earth’s 4.5 billion-year history, Homo sapiens has certainly put its stamp on the place. Humans have had a direct impact on more than three-quarters of the ice-free land on earth. Almost 90% of the world’s plant activity now takes place in ecosystems where people play a significant role. We’ve stripped the original forests from much of North America and Europe and helped push tens of thousands of species into extinction. Even in the vast oceans, among the few areas of the planet uninhabited by humans, our presence has been felt thanks to overfishing and marine pollution. Through artificial fertilizers – which have dramatically increased food production and, with it, human population – we’ve transformed huge amounts of nitrogen from an inert gas in our atmosphere into an active ingredient in our soil, the runoff from which has created massive aquatic dead zones in coastal areas. And all the C02 that the 7 billion-plus humans on earth emit is rapidly changing the climate – and altering the very nature of the planet.

Human activity now shapes the earth more than any other independent geologic or climatic factor. Our impact on the planet’s surface and atmosphere has become so powerful that scientists are considering changing the way we measure geologic time. Right now we’re officially living in the Holocene epoch, a particularly pleasant period that started when the last ice age ended 12,000 years ago. But some scientists argue that we’ve broken into a new epoch that they call the Anthropocene: the age of man. “Human dominance of biological, chemical and geological processes on Earth is already an undeniable reality,” writes Paul Crutzen, the Nobel Prize-winning atmospheric chemist who first popularized the term Anthropocene. “It’s no longer us against ‘Nature.’ Instead, it’s we who decide what nature is and what it will be.”

To carry this line of reasoning one step further: with the advent of genetic engineering and the growing understanding of human psychology and neurology, it is also we who might decide what human nature will be. That old Existentialist adage, “existence precedes essence,” used to apply just to one’s own self-understanding; the suggestion was that, from the subjective viewpoint of lived experience, one first finds oneself existing, and then discovers that one’s “essence” or “nature” follows from what one chooses to do. But now it appears that this might soon become true not just from a subjective point of view, but also from an objective, scientific one: it seems that not only human nature, but also nature itself has become our responsibility. And given our track-record up to now, this should certainly cause some angst.

Climate Change’s Closing Door

Share

The Guardian reported last November that, judging by “the most thorough analysis yet of world energy infrastructure”, we likely have little more than five years left to put a lid on carbon emissions before losing the chance of avoiding serious climate change. Although I’ve never been tempted to doubt the scientific consensus on climate change, I think I’ve been relying on wishful thinking to avoid feeling too anxious about it (probably like almost everyone else), but I’ve got to admit that these warnings are starting to get to me-

The world is likely to build so many fossil-fuelled power stations, energy-guzzling factories and inefficient buildings in the next five years that it will become impossible to hold global warming to safe levels, and the last chance of combating dangerous climate change will be “lost for ever”, according to the most thorough analysis yet of world energy infrastructure.

Anything built from now on that produces carbon will do so for decades, and this “lock-in” effect will be the single factor most likely to produce irreversible climate change, the world’s foremost authority on energy economics has found. If this is not rapidly changed within the next five years, the results are likely to be disastrous.

“The door is closing,” Fatih Birol, chief economist at the International Energy Agency, said. “I am very worried – if we don’t change direction now on how we use energy, we will end up beyond what scientists tell us is the minimum [for safety]. The door will be closed forever.”

If the world is to stay below 2C of warming, which scientists regard as the limit of safety, then emissions must be held to no more than 450 parts per million (ppm) of carbon dioxide in the atmosphere; the level is currently around 390ppm. But the world’s existing infrastructure is already producing 80% of that “carbon budget”, according to the IEA’s analysis, published on Wednesday. This gives an ever-narrowing gap in which to reform the global economy on to a low-carbon footing.

If current trends continue, and we go on building high-carbon energy generation, then by 2015 at least 90% of the available “carbon budget” will be swallowed up by our energy and industrial infrastructure. By 2017, there will be no room for manoeuvre at all – the whole of the carbon budget will be spoken for, according to the IEA’s calculations

Funny, I don’t remember hearing about the IEA report via American mass media, although given how little time they spend on reporting scientific findings, I guess that shouldn’t surprise me. I’m still patiently waiting for an intrepid reporter at one of the zillion Republican debates to challenge Rick Santorum on his explicit climate change denial in the face of the ever mounting evidence. He did say recently: “You hear all the time, the left – ‘Oh, the conservatives are the anti-science party.’ No we’re not. We’re the truth party.” Surely that invites a polite question on what he means by “the truth” here, and how he would go about establishing it…

By the way, lest you think that the IEA is some liberal advocacy group whose studies can’t be trusted, it’s actually an international organization with 28 member states, including all of the following-

Put This Anecdote In Your Pipe And Smoke It

Share

Montana Public Broadcasting has produced an interesting documentary on the controversy surrounding medical marijuana. Critics will no doubt cite the anecdotal nature of the evidence in favor of medical use, but supporters will point out the weaknesses of the objections to medical use and the apparent inconsistencies in the federal government’s policies. Did you know, for instance, that federal law allows Schedule II drugs – which include methamphetamine, cocaine, opium and morphine – to be prescribed for medical purposes, but not marijuana, which is listed on Schedule I as a drug with a high potential for abuse but no medical use?

We embed, you decide-

Watch the full episode. See more MontanaPBS Presents.

The Trouble With Internet Filter Bubbles

Share

One of my favorite Yes songs, back in the day, was “Don’t Surround Yourself With Yourself”. Although the lyrics meandered a bit, the title seemed a worthy piece of advice. Unfortunately, for various reasons (including, of course, targeted marketing and advertising), internet search engines – and social networking sites like facebook – are increasingly surrounding each of us with what they “think” we want, and burying or even filtering out search results they “think” we’ll find irrelevant. Eli Pariser, author of The Filter Bubble: What the Internet is hiding from you, would like you to seriously consider the possible long-term consequences of this growing trend. Here’s a ten minute talk he gave on the subject-

Thanks to Laura Knaapen for publicizing this video via a discussion list at my University.

Republicans Contra Science

Share

It’s one thing to disagree about what to do about global warming, and even about the exact causes of global warming, but every single Republican on the House Energy and Commerce Committee voted against a simple statement of the scientifically uncontroversial fact that global warming is occurring! As reported by The Hill-

Committee ranking Democrat Rep. Henry Waxman (D-Calif.) offered an amendment Tuesday that called on Congress to agree that climate change is occurring. The amendment failed on a party-line vote of 20-31. No Republicans voted for the amendment.

The amendment says that “Congress accepts the scientific finding of the Environmental Protection Agency that ‘warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.’”

“This finding is so obviously correct that there should be no need to offer the amendment,” Waxman said.

Waxman is right. Denying that global warming is occurring is like denying that the Earth is (roughly) spherical. These Republicans seem to be concerned that admitting a fact might trap them into agreeing to a policy they would find unpalatable, but reality never dictates policy (just as facts don’t dictate values). Perhaps they are denying the facts in order to avoid revealing their true values…

Nuclear Reactors, Control Rods, and Meltdowns

Share

So… I was wondering how an earthquake could possibly cause a meltdown at the Fukushima Daiichi nuclear facility in Japan, given that the plant operators had been able to fully insert the control rods into the core. I had to search for a few minutes to find an explanation by someone who actually knew what they were talking about – in this case, Alexey Petrov, an Associate Professor at the Department of Physics and Astronomy at Wayne State University. Here is an informative excerpt from his post, which can be found here-

Diagram of a BWR-type nuclear reactor

Here is the scheme of BWR-type reactor, taken from the Wikipedia page on BWR. The physics here is very simple. Fission reaction in the uranium fuel assemblies (2) heat water (blue stuff, 7), which turns into steam (red stuff, 6) in the reactor vessel (1). The steam exits the vessel and spins the turbine (8 and 9) that generates electricity. That steam is cooled down and returned into the reactor vessel and the process begins again.

Simply speaking, fission reaction happens when a slow (thermal) neutron is absorbed by uranium (U-235) nucleus, which then splits into several (two) lighter daughter nuclei, neutrons (about 3) releasing energy that is converted into heat. In order to have sustained nuclear reaction one needs to slow down those produced neutrons so that they could be absorbed by other U235 nuclei to initiate fission reaction. Different reactor designs use different moderators to do that: water (BWR, PWR), graphite (RBMK), etc.

This simple excursion into nuclear physics tells us that the rate of power generation can regulated by controlling the flux of thermal neutrons. This is indeed what is done by the control rods (3) that are usually made of a material (boron) that absorbs neutrons.

What happens in case of an earthquake? Well, the automatic control systems first and foremost would kill the sustained fission reaction that is going in the fuel elements. This was done at the Fukushima plant immediately by inserting the control rods (notice that the control rods are inserted from below). So, what’s the problem then? Why is the water vapor’s pressure is rising?

The problem is that during the fission reaction one also produces a lot of short-lived nuclear isotopes. Normally, if you would like to shut down a reactor (say, to refuel), you need some time (several days) for those isotopes to decay. During this time, the water is still being circulated through the reactor core in order to take away the heat produced in the decays of those short-lived isotopes. This is done via pumps that are operated via (1) power grid or (2) diesel generators or (3) batteries. After the earthquake the grid was knocked out and the diesel generators damaged. The pumps are now running on the batteries and the water vapor pressure inside the reactor vessel is rising — by the way, the normal operating pressure there is about 75 atmospheres!!! TEPCo [Tokyo Electric Power Company, the plant's owner - ed.] reports that the pressure there rose twice that, so the plant operators decided to release steam from the vessel. Now, to cool down the reactor (until those short-lived isotopes decay) they decided to flood the containment vessel with sea water.

So, as you see, the Chernobyl-type of explosion is highly unlikely at the Fukushima plant.

Well, that’s a relief… But (UPDATE 3/15) that doesn’t mean we’re not in for a disaster, according to the New York Times-

“We are on the brink. We are now facing the worst-case scenario,” said Hiroaki Koide, a senior reactor engineering specialist at the Research Reactor Institute of Kyoto University. “We can assume that the containment vessel at Reactor No. 2 is already breached. If there is heavy melting inside the reactor, large amounts of radiation will most definitely be released.”

Another executive said the chain of events at Daiichi suggested that it would be difficult to maintain emergency seawater cooling operations for an extended period if the containment vessel at one reactor had been compromised because radiation levels could threaten the health of workers nearby. If all workers do in fact leave the plant, the nuclear fuel in all three reactors is likely to melt down, which would lead to wholesale releases of radioactive material — by far the largest accident of its kind since the Chernobyl.

On Why There Is Something Rather Than Nothing

Share

An article today in the New York Times reports that, in physics anyway, we are on the verge of discovering why there’s something rather than nothing… or at least why the Big Bang has produced more matter than anti-matter. It all has to do with “the behavior of particularly strange particles called neutral B-mesons, which are famous for not being able to make up their minds”-

They oscillate back and forth trillions of times a second between their regular state and their antimatter state. As it happens, the mesons, created in the proton-antiproton collisions, seem to go from their antimatter state to their matter state more rapidly than they go the other way around, leading to an eventual preponderance of matter over antimatter of about 1 percent, when they decay to muons.

Whether this is enough to explain our existence is a question that cannot be answered until the cause of the still-mysterious behavior of the B-mesons is directly observed, said Dr. Brooijmans, who called the situation “fairly encouraging.”

The observed preponderance is about 50 times what is predicted by the Standard Model, the suite of theories that has ruled particle physics for a generation, meaning that whatever is causing the B-meson to act this way is “new physics” that physicists have been yearning for almost as long.

Dr. Brooijmans said that the most likely explanations were some new particle not predicted by the Standard Model or some new kind of interaction between particles. Luckily, he said, “this is something we should be able to poke at with the Large Hadron Collider.”

Okay guys, get poking! But, of course, a new model that explains the matter-anti-matter asymmetry better than the old “standard” model won’t solve the Really Big Question that metaphysicians, like very young children, always have at the ready: why? Why has this (fill in any impressively predictive physical model you like) ever happened? It seems unlikely that any merely descriptive theory, no matter how useful, will ever satisfy those who find this question engaging. Of course, it’s easy to write the question off as presupposing a sort of anthropomorphism, as if a universe had to be designed for a reason or purpose. But I think the question goes deeper than that, because even if you recognize that expecting the universe to have a purpose or a raison d’être is committing a sort of logical error or “category mistake”, the question still feels sensible. Maybe such a feeling just indicates that one is banging up against the limits of the human mind… and maybe not.