A new field

I was fortunate enough that the day-job of my bandmate of many years, Kathy Selby, was working as a physicist at Cornell University.

As you might suspect, our conversations while traveling to gigs were pretty interesting.

One time we were on our way to play for a dance in Rochester, and I asked her what she thought about dark matter and dark energy -- which according to current models make up, respectively, 27% and 68% of the mass-energy content of the universe.  [Nota bene: the use of the word "dark" in both names does not mean that they are in any sense the same thing.  Dark matter is a name for the observation that the gravitational attraction of conventional matter is insufficient to account for the measured velocities of galaxies and galaxy clusters; there must be some other, unseen matter there that does not interact with ordinary matter electromagnetically, or else our model for gravity is incorrect.  Dark energy, on the other hand, is a theoretical energy inherent in space itself that might explain the accelerating expansion of the universe.]

So yes, only five percent of the universe is the regular stuff we see around us on a daily basis.  The other 95% is largely unexplained, and is yet to be detected directly.

In any case, I asked Kathy what her opinion was about the rather uncomfortable situation of having the vast majority of the universe thus far inaccessible to scientific study.

"In my opinion," she said, "we're in a situation a bit like physicists were in the late nineteenth century.  They knew light had strange properties.  It acted like a wave much of the time, so they'd postulated a medium -- the luminiferous aether -- through which the wave was propagating.  The problem was, every attempt to detect the aether failed.  Then Michelson and Morley came along and showed that the prediction of an 'aether drag' caused by the motion of the Earth through space didn't exist, suggesting very much that the aether didn't either.  The speed of light in a vacuum seemed to be the same in all reference frames, which was unlike any other wave ever studied.  Then Einstein said, 'Well, let's start by assuming that the speed of light in a vacuum is the same regardless of your reference frame, and see what happens,' and the aether became unnecessary.  Of course, what came out of that shift in perspective was the Theories of Relativity.

"What I think," she concluded, "is that we're waiting for this century's Einstein to tell us that we've been looking at everything the wrong way -- and suddenly the problems of dark matter and dark energy will evaporate, just like the aether did."

Well, we may have just gotten a glimpse at one possibility for that shift in perspective, courtesy of physicist Lucas Lombriser of the Université de Genève.

A paper published two weeks ago in the journal Classical and Quantum Gravity started by looking at what has been called "the worst prediction in physics" -- the value of the cosmological constant, which sets the expansion rate of the universe.  The prediction by theoretical physicists of what the cosmological constant should be given what we know about matter, and what we actually measure it to be, differ by 120 orders of magnitude -- that's 1 followed by 120 zeroes.

Oops.  Major oops.  This is what gave rise to the mysterious dark energy, some peculiar property of space itself that solves the mismatch.  But as far as what exactly this dark energy might be, physicists have come up empty-handed, so more and more it's seemed like a placeholder to cover up for the fact that we don't really understand what's going on.

This, Lombriser says, is because -- like with Einstein's solution to the aether -- we're starting out with the wrong assumption.

Maybe the universe is flat and static, as Einstein himself believed (after the discovery of red shift and the expansion of the universe, Einstein was forced unwillingly to accept an expanding universe and a cosmological constant -- which he later called "the greatest blunder of my career").  Perhaps space isn't expanding; it's the masses of particles that have changed over time.  The altered masses change the gravitational field that permeates space, and that's what generates red shift and the appearance of expansion.  So there is a cosmological constant, but it comes from the particles themselves, and the field in which they reside, evolving.

[Image licensed under the Creative Commons Original image by User:Vlad2i, slightly modified by User:mapos., Gravitational red-shifting2, CC BY-SA 3.0]

This new take solves three problems at once.  It does away with the cosmological constant mismatch; dark energy pretty much disappears completely; and the field itself that's responsible for the mass change could account for dark matter, as it shares many properties with an axion field, and axions are one of the leading candidates for the constituents of dark matter.  

This simultaneous solution of three vexing problems is certainly intriguing.  But the question is, is Lombriser right?  "The paper is pretty interesting, and it provides an unusual outcome for multiple problems in cosmology," said physicist Luz Ángela García, of the Universidad ECCI Bogotá, who was not involved in the research.  "The theory provides an outlet for the current tensions in cosmology.  However, we must be cautious.  Lombriser's solution contains elements in its theoretical model that likely can't be tested observationally, at least in the near future."

Which, of course, is the issue, and is all too common in this branch of science.  Even though Einstein's Theories of Relativity did a good job of accounting for various anomalies in the properties of light, the first precise confirmation of his predictions didn't occur until 39 years after he wrote his seminal paper in 1915.  How to detect the fluctuating field Lombriser postulates -- and, more importantly, how to distinguish its effects from the current model of expanding space -- is currently beyond us.

So maybe Lombriser is what my bandmate Kathy called "this century's Einstein."  Or maybe his ideas will prove to be just another unverified or (worse) unverifiable hypothesis.  But I have to say, when I read about what he's proposing, my ears did perk up.  It has the feel of a paradigm shift -- just what we've been waiting for.

And you can bet that the physicists are going to be all over this, looking for ways either to confirm or refute what he's saying.

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Rock recall

First, we had a "Quantum Pendant" that was supposed to realign your chakra frequencies (or something like that), but was recalled when the authorities found the rock it was made from was actually radioactive.  Then we had the warning issued because people with ear wax impactions were sticking lit candles in their ears to "suck out the wax," which resulted in several hospitalizations and at least one person setting their house on fire. Yet another warning was put out by doctors when the woo-woos started recommending taking off all your clothes and exposing your butthole to direct sunlight, risking a sunburn that I don't even want to think about.  Then there were the homeopathic "remedies" that were taken off the shelves because, by some horrific mistake, they turned out to have some actual active ingredients.

So you'd think after all this -- and, allow me to say, I didn't make any of the above up -- either (1) the general public would realize that the woo-woo alt-med types are full of shit and stop listening to anything they say, or (2) I'd stop being surprised by what new idiotic "natural health" fads crop up.

Neither of those, in fact, has happened.

This comes up because of a loyal reader of Skeptophilia who sent me a link to a story out of Australia about a company that distributes chunks of a rock called rough serpentine to stores specializing in woo-woo crystal nonsense.  Serpentine is common -- it's a characteristic rock found in areas that once were part of oceanic plates -- but it's pretty enough.  It often has green and black bands, and occurs in two main forms, a shiny, smooth "platy" variety (sometimes nicknamed "false jade"), and a fibrous, grainy "rough" variety.  If you're curious about what they claim serpentine can do, one source says that it "is believed to help establish control over one's life.  According to metaphysical beliefs, serpentine provides a clearing of thought to better facilitate meditation.  Serpentine is said to clear clouded areas of the chakras and stimulate the crown chakra, promoting spiritual understanding and psychic abilities."

Pretty impressive, no?

There's a wee problem with rough serpentine, though.

It contains asbestos.

Rough serpentine [Image licensed under the Creative Commons Tiia Monto, Talk on Serpentine, CC BY-SA 3.0]

Asbestos exposure, as I probably don't need to mention, is associated with lung cancer, emphysema, and mesothelioma.

"Consumers should immediately stop using this product and wrap it in thick sturdy plastic or a heavy duty sturdy plastic bag where the seal cannot be broken," said a spokesperson for the Australian Competition and Consumer Commission.  "The supplier – Alliz Trading Pty Ltd – will contact consumers to provide advice about safe disposal of the stones and arrange a full refund."

I really shouldn't be surprised this happened.  It's all part and parcel of the "if it's natural, it must be good for you" mentality, which conveniently ignores the fact that strychnine is all-natural and 100% organic.

For what it's worth, this was completely natural, too.  I'm guessing the dinosaurs' chakras were pretty fucking clouded afterward, though.  Pity no one was around to give them some serpentine.

In any case, it brings home the fact that modern science and medicine have done a good job of improving our lives.  Yes, they're far from perfect.  I'm aware of the issues with the pharmaceuticals industry, and the ongoing health insurance mess here in the United States.  I know that modern technology has created a good many problems itself.  But on balance, we live longer, healthier lives, and more of our children survive to adulthood, than ever before, and that's not because more of us are waving crystals around, taking "remedies" that have been diluted to the point that there's basically nothing left but water, or (heaven forfend) exposing our nether orifices to direct sunlight.

So learn a little science, okay?  And stay away from rocks containing asbestos.  Those things are dangerous.

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Out of line

Every so often, I run into a claim that some archaeological site aligns with a particular astronomical object, and all too often, everyone decides that the alignment is why the site was built where and how it was.

Trying to parse the motives of long-dead people who left nothing in the way of written records is a dicey business.  In fact, sometimes it's hard enough even when you're talking about extant cultures.  This was brilliantly lampooned in Horace Miner's rightly famous 1956 article "Body Ritual Among the Nacirema," which appeared in American Anthropologist, and took a rigorous and scholarly look at the mysterious "shrines" we all have in our houses...

... better known as "bathrooms."  And, of course, reached the wrong conclusions about the purposes of nearly everything in them.

The problem arises because the human brain is a pattern-finding device, so it's often hard to resist our tendency to see a pattern when there is none there.  This is the origin of the phenomenon of ley lines -- which I wrote about twelve years ago, in one of my earliest Skeptophilia posts -- the claim that towns, cities, and religious sites are laid out along "lines of power" generated by some unknown forces in the Earth itself.  There are a couple of completely prosaic reasons this alignment happens:

1. Populated sites in areas with relatively flat topography are frequently connected by straight lines, because as Papa Euclid taught us, the shortest distance between two points is a straight line.
2. More interestingly -- and germane to the pattern-finding tendency referenced above -- if you aren't given any constraints about what particular places you're trying to connect, you can almost always find completely accidental correlations that look like deliberate alignment.

The latter is why the whole topic comes up, because of a fun site I stumbled on called Spurious Alignments: Bad Archaeoastronomy At Your Fingertips.  What this site does is allow you to overlay various astronomical benchmarks (e.g. sunrise on the Winter Solstice, the northernmost point on the horizon where Jupiter rises, and so on) on top of particular geographic locations -- and see what correlations you can find.

One of the best ones anyone's found so far is the airport in Palermo, Italy.  Here are a few of the relevant discoveries:

• Runway 07/25 tracks the relative motions of the Moon.
• Runway 02/20 aligns with the rise of the star Capella.
• Taxiways Bravo and Charlie align with the setting of the star Procyon.
• Taxiway Delta points directly toward the setting of the star Arcturus.

From this, we can clearly see that the Palermo Airport is a site built by ancient astronomers, and the whole complex is an observatory, or possibly the center of a sky-worshiping cult.

The difficulty, of course, is some sites were created because of astronomical alignments.  Many of our distant ancestors knew the motions of the skies better than your average person does today.  A good example, not really explainable any other way, is the famous Sun Dagger on Fajade Butte in New Mexico.  A spiral design carved into the side of a rock facing is across from a crack between two stones, and -- only on the Summer Solstice -- this crack allows light from the Sun at midday to form a "dagger" that perfectly bisects the spiral.

The Sun Dagger is pretty clearly a solstice marker, allowing people to keep track of the seasons in a climate that was hostile to say the least.

But as for most of the other "ancient astronomical observatory" claims -- well, maybe.  It's too easy to find spurious correlations and alignments, especially when there are no rules about what you're trying to get the site to align to.

Or, maybe, the people who built the Palermo Airport really were trying to tell us something.  You never know.

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Heavy-duty nonsense

Yesterday I ran into a claim that, even by comparison with most alt-med nonsense, is way out there. The gist of it is that you can fix all your physical ailments if you just stop drinking water with deuterium in it.

Deuterium, as I probably don't need to explain, is "heavy hydrogen" -- hydrogen atoms whose nucleus contains a proton and a neutron (rather than only a proton, as in ordinary hydrogen).  Heavy water has a few different physical and chemical properties from ordinary water -- such as (unsurprisingly) being 10.6% more dense and being more viscous.  It has an ability to slow high-energy neutrons down without absorbing them, making heavy water important in nuclear fission reactors. Additionally, deuterium forms stronger bonds to carbon and oxygen than ordinary hydrogen.

[Image licensed under the Creative Commons Dirk Hünniger; Derivative work in english - Balajijagadesh, Hydrogen Deuterium Tritium Nuclei Schmatic-en, CC BY-SA 3.0]

The "Beginner's Guide to Deuterium and Health," however, has some information that would be seriously scary if it weren't for the fact that nearly all of it is wrong.  It starts with a definition of "deuterium," which is correct, and is honestly the last thing on the entire webpage that is.  You're put on notice about the veracity of the site in the first paragraph, wherein we find that the details of how awful deuterium is for you is only accessible to "those with an understanding of advanced bio-chemistry, bio-physics and quantum health."

What, pray, is "quantum health?"  The health of your subatomic particles?  The health of people who are so extremely small that they can only be detected with sensitive instruments?  The health of people who jump from "sick" to "well" and back again without passing all the stages in between?

Or, perhaps, does it refer to someone who is both sick and well at the same time until they go to a doctor, at which point the Alt-Med Wave Function collapses, and they become one or the other?

Then we find out that our health depends on how fast our mitochondria are spinning.  No lie, here's the relevant passage:

At a quantum level hydrogen plays a vital role in mitochondria function.  Mitochondria are the powerhouse batteries of the body.  They ultimately facilitate energy production.  Within the mitochondria there is a spinning head that rotates very fast, the rotation speed of this spinning head determines how efficiently you create energy.  The faster the spinning head rotates the more energy you make and the healthier you will be.  The slower the spinning head rotates the less energy you will make and this leaves you more susceptible to chronic mismatch diseases and faster aging.

What this is referring to, insofar as I can understand it, is the electron transport chain, wherein electrons in your mitochondria give up some of their energy through a series of oxidation/reduction reactions, and that energy is used to shuttle hydrogen ions across the mitochondrial membrane.  The ultimate result is the generation of ATP, a crucial energy storage molecule.

The amusing part is that the rate of this reaction is controlled incredibly tightly.  You need about seventy million ATP molecules per second, per cell, and you use them equally quickly -- ATP doesn't store well.  If your rate of production went up without your rate of consumption going up, you wouldn't be healthier; the ATP would break down, liberating the energy as heat, and you'd spontaneously burst into flame.

So the site is right to the extent that if this happened, worrying about illness and aging would be down near the bottom of your Priorities List.

Anyhow, what we're told is that deuterium kind of gums up the works, making the "spinning head" run more slowly, giving us chronic diseases.  What kind of chronic diseases is never specified, because apparently they're all caused by the same thing, whether you're talking about arthritis or high blood pressure.

The pièce de resistance, however, is when the website tells us what to do about all this.  In order to avoid this bad stuff, the solution is simple: we have to start drinking water with the deuterium removed.

But how do you do this?

Easy.  You take ordinary tap water, and freeze it.

If you put water in the freezer, they say, the heavy water will freeze first.  So you wait until a crust of ice forms, and either chip off and remove that, or else pour off the still-liquid part of the water.  Do it again and again, and eventually you'll have healthful "deuterium-depleted" water.

It works even better, they say, if you start with water "from glacial regions," because it's already been de-deuterium-ized naturally.

I know that the people who construct nuclear reactors would be glad to hear this.  The current method of producing heavy water for industry is called the Girdler sulfide process, which produces one ton of heavy water for every 340,000 tons of water you start with.  This means the stuff's expensive -- one place I looked is charging $680 per liter.  If all they had to do is freeze regular water and pull off the ice, it'd be quite a cost savings.

As with many wacky claims, there's a (small) grain of truth to this stuff.  Heavy water does have a higher freezing point than ordinary water (3.7 C as compared to 0 C).  It's also toxic, but only if you replace 25% of your body's water content with heavy water -- an expensive proposition given its cost.  (One source said, "accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard.  Poisoning would require that the victim ingest large amounts of heavy water without significant normal water intake for many days to produce any noticeable toxic effects.")

What about our consumption of heavy water from contamination of ordinary water?  Well, since in virtually all tested water sources, the concentration of heavy water is one part in 3,200, I don't think you have much to worry about.  But if it amuses you to partly freeze your drinking water and throw away the icy part, by all means have at it.

Oh, and the website also says that once you "flush out the deuterium" from your body, your "energy level will increase, along with your magnetic field."  Which sounds potentially dangerous to me.  I would hate to have just made myself all healthy and deuterium-free, then I walk into Home Depot and my magnetic field starts attracting metal implements, and I get impaled in the forehead by a screwdriver or something.

So there you have it.  How to go through a lot of folderol to remove something from your water that (1) is there in vanishingly small amounts, and (2) has no toxic effects at that dosage.  Me, I'm more inclined to eat right and exercise regularly, but maybe I'm only saying that because the deuterium has gummed up the "spinning heads" in my brain's mitochondria and I'm not thinking straight.  You can see how that could happen.

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Kablooie

I'm kind of an excitable type.

I think that may be why I went into science.  The rigorous, evidence-basted methods of science were a nice antidote to the fact that my natural state is having my emotions swinging me around by the tail constantly.

Even after years of studying (and teaching) science, and twelve years of writing about it here at Skeptophilia Central, I still have the capacity for going off the deep end sometimes.  Which is what happened when I read a paper (a preprint, actually) from the Monthly Notices of the Royal Astronomical Society called "The Evolutionary Stage of Betelgeuse Inferred from its Pulsation Periods," by Hideyuki Saio (Tohoku University) and Devesh Nandal, Georges Meynet, and Sylvia Ekström (Université de Genève).

The constellation Orion.  Betelgeuse is in the upper left corner of the image.  [Image licensed under the Creative Commons Mouser, Orion 3008 huge, CC BY-SA 3.0]

First, a little background, before I get to the squee-inducing part.

Stars exist in a state of tension between two forces -- the inward pull of gravity and the outward pressure from the heat produced by fusion in the core.  At the very beginning of their lives, stars form from a loose cloud of mostly hydrogen gas that collapses under its own attractive gravitational force.  That collapse increases the pressure and temperature, and -- if the initial cloud was big enough -- eventually they rise high enough to trigger the fusion of hydrogen atoms into helium.  This is a (very) energy-releasing reaction -- physicists call such reactions exothermic -- and that energy pushes outward, balancing the inward pull of gravity.  The star goes into equilibrium.

But there's not an infinite supply of hydrogen.  The hydrogen fuel in the core is eventually exhausted, so fusion slows down.  The temperature drops, as does the outward pressure, so -- for a while -- gravity wins.  The star collapses, heating the core up, until the temperature and pressure become sufficient to fuse the helium "ash" in the core into carbon.  (This process, incidentally, is where the carbon in the organic molecules in our bodies comes from; Carl Sagan was spot-on in saying "We are made from star stuff.")

Helium fusion is also exothermic, so once again, the star goes into equilibrium.  But then the helium runs out, and the collapse resumes until the pressure and temperature are high enough to fuse carbon into oxygen. 

Then oxygen into silicon.  Then silicon into iron.

Two things are important here.  The first is that each of the reactions -- from hydrogen fusing into helium through silicon fusing into iron -- produces less energy than the one before it but requires higher temperatures and pressures to make it happen.  The second is that something happens when you pass that final reaction, which is that any subsequent fusion into heavier elements is an endothermic, or energy-consuming, reaction.

So when the silicon is used up, and the star's core is made mostly of iron, there's pretty much nowhere to go.  The gravitational collapse picks up again, and there is no "next reaction" that might produce energy to balance it.  So the collapse continues until finally there's such a tremendous temperature spike that the entire star goes kablooie.

This is called a supernova, and it releases more energy in a few seconds than the star liberated in the entire rest of its life.  The unimaginable pressures do fuse some of the iron in the core into those heavier elements, despite the energy required, and that's where all the elements on the periodic table with atomic numbers higher than 26 come from, from the gold in our jewelry to the silver in our coinage and the copper in our electrical wires.

With me so far?  Because there's one more thing I haven't told you.

Each stage in a star's life takes much less time than the one before it.

The hydrogen to helium stage lasts millions to billions of years.  (The Sun is in the hydrogen-burning stage, and is estimated to have another five billion years to go.)  Higher-mass stars have higher pressures and temperatures, and consume their fuel at a greater rate, but we're still talking tens to hundreds of millions of years.  Helium-to-carbon lasts maybe a million years; carbon-to-oxygen, we're talking decades.

After that, it's pretty much a ticking time bomb with a very short fuse.

Now for the punch line: the Saio et al. paper suggests that the pulsation periods of the red supergiant star Betelgeuse indicate that it is nearing the end of the carbon burning stage.  So we might actually have a shot at seeing one of the brightest stars in the sky go supernova in our lifetimes.

This paper has even the scientists flipping out.  One of my favorite science vloggers, astronomer Becky Smethurst of Oxford University, did a YouTube video about this paper and you could tell she was barely keeping it together.  Ordinarily, whenever you hear about anything impressive in sciences like astronomy and geology -- such as a supernova or gamma-ray burster, or the Yellowstone Supervolcano erupting or the East African Rift Zone tearing Africa apart -- the scientists will respond with a deep sigh and a monotone "as we've explained many times before, blah blah blah astronomical/geological time scales blah blah blah."

Now, though, the astronomers are actually acting like this is the real deal.  (And in fact, if Saio et al. are right, Betelgeuse has probably already blown itself to smithereens; at six-hundred-odd light years away, we just haven't gotten the memo yet.)

When this happens, it's gonna be spectacular.  A supernova that close will be bright enough to read by at night, most likely for months, and will be easily visible during the day.  The happy news is that it's not close enough to do us any damage; a supernova under twenty-five light years away could be catastrophic, doing nasty stuff like blowing away the atmosphere.  (Fortunately, there are no supernova candidates anywhere near that close to us.)  Betelgeuse will just create some amazing fireworks, as well as permanently changing the contour of the familiar constellation of Orion.

So my opinion is: bring on the supernova.  We could use a little excitement down here.

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Walkabout

I'm always amazed at the depth of information paleontologists can glean from fossils.

And I'm not even including the ones that show exceptional preservation, like the ichthyosaur fossils I mentioned in a post a couple of days ago, that were so well preserved that they could even determine features like countershading.  Ordinary fossils contain a wealth of information about the organisms they came from -- if you know where to look, and how to interpret it.

Take, for example, the paper by a team from the University of Bristol and the University of Uppsala that appeared last week in the journal Alcheringa: An Australasian Journal of Paleontology.  Conducted by Christine Janis, Adrian O'Driscoll, and Benjamin Kear, the study analyzed the bones of prehistoric kangaroos, and reached a rather startling conclusion: a good many ancient kangaroo species didn't have the group's signature hop.

The determination came from looking at the strength and articulation of the leg bones, as well as the animal's overall size.  In particular, the short-faced kangaroos, or sthenurines, may have preferred to walk on all fours -- or might even have had a bipedal stride like a human.

The skeleton of Simosthenurus occidentalis, which I find vaguely terrifying. [Image licensed under the Creative Commons Ghedoghedo, Simosthenurus occidentalis, CC BY-SA 3.0]

You can see why they're called short-faced kangaroos in the artist's recreation of Procoptodon goliah below, in which I notice two things:

1. These creatures looked like a cross between a bunny rabbit and Godzilla.
2. The woman posing next to it has a stance like a Glamour magazine model, which is an odd thing to do if you're confronted with an eight-foot-tall kangaroo with giant claws.  Me, I'd be running like hell, if I didn't just wet my pants and then faint.

[Image licensed under the Creative Commons Nobu Tamura, Procoptodon goliah NT, CC BY-SA 4.0]

The striding kangaroos seem to have split off from the hopping kind about fifteen million years ago, during the Miocene Epoch, when Australia was a lot wetter than it currently is.  The climate back then would have favored large herbivores like the sthenurines (thank heaven these things weren't carnivorous), and they simply became too heavy to jump efficiently.  Even smaller sthenurines, though, had a different leg articulation -- they all appear to have been walkers rather than hoppers.

The last of the striding kangaroos went extinct during the last Ice Age, when the climate took a turn toward more arid conditions.  Aridity meant fewer plants, and slower growth for the ones that survived, and the largest marsupials in Australia died out.

Just as well.  Even the kangaroos that are left can kick you into the middle of next week; every year people, mostly stupid tourists, are injured by kangaroos.  Australians also have to contend with the various venomous snakes, spiders, and jellyfish, a relative of the nettle (the gympie-gympie) whose spines inject a neurotoxin that causes intense pain for years, and a highly-aggressive bird called the cassowary that looks like the bastard child of a turkey and a velociraptor.  The last thing those poor people need is giant kangaroo-bunnies striding around like they own the place.

Because the kangaroo-bunnies probably were vicious.  Down there, it's kind of an inevitability.

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Trompe l'oeil

I have a fascination for optical illusions.

Not only are they cool, they often point out some profound information about how we process sensory input.  Take the famous two-and-a-half pronged fork:

The problem here is that we're trying to interpret a two-dimensional drawing as if it were a three-dimensional object, and the two parts of the drawing aren't compatible under that interpretation.  Worse, when you try to force your brain to make sense of it -- following the drawing from the bottom left to the top right, and trying to figure out when the object goes from three prongs to two -- you fail utterly.

Neil deGrasse Tyson used optical illusions as an example of why we should be slow to accept eyewitness testimony.  "We all love optical illusions," he said. "But that's not what they should call them.  They should call them 'brain failures.'  Because that's what they are.  A clever drawing, and your brain can't handle it."

(If you have some time, check out this cool compendium of optical illusions collected by Michael Bach, which is even more awesome because he took the time to explain why each one happens, at least where an explanation is known.)

It's even more disorienting when an illusion occurs because of two senses conflicting.  Which was the subject of a paper out of Caltech, "What You Saw Is What You Will Hear: Two New Illusions With Audiovisual Postdictive Effects," by Noelle R. B. Stiles, Monica Li, Carmel A. Levitan, Yukiyasu Kamitani, and Shinsuke Shimojo.  What they did is an elegant experiment to show two things -- how sound can interfere with visual processing, and how a stimulus can influence our perception of an event, even if the stimulus occurs after the event did!

Sounds like the future affecting the past, doesn't it?  It turns out the answer is both simpler and more humbling; it's another example of a brain failure.

Here's how they did the experiment.

In the first trial, they played a beep three times, 58 milliseconds apart.  The first and third beeps were accompanied by a flash of light.  Most people thought there were three flashes -- a middle one coincident with the second beep.

The second setup was, in a way, opposite to the first.  They showed three flashes of light, on the right, middle, and left of the computer screen.  Only the first and third were accompanied by a beep.  Almost everyone didn't see -- or, more accurately, didn't register -- the middle flash, and thought there were only two lights.

Sorry, I had to.

"The significance of this study is twofold," said study co-author Shinsuke Shimojo.  "First, it generalizes postdiction as a key process in perceptual processing for both a single sense and multiple senses.  Postdiction may sound mysterious, but it is not—one must consider how long it takes the brain to process earlier visual stimuli, during which time subsequent stimuli from a different sense can affect or modulate the first.  The second significance is that these illusions are among the very rare cases where sound affects vision, not vice versa, indicating dynamic aspects of neural processing that occur across space and time.  These new illusions will enable researchers to identify optimal parameters for multisensory integration, which is necessary for both the design of ideal sensory aids and optimal training for low-vision individuals."

All cool stuff, and more information about how the mysterious organ in our skull works.  Of course, this makes me wonder what we imagine we see because our brain anticipates that it will there, or perhaps miss because it anticipates that something out of of place shouldn't be there.  To end with another quote from Tyson: "Our brains are unreliable as signal-processing devices.  We're confident about what we see, hear, and remember, when in fact we should not be."

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