Glossy magazines often contain a substance that has elevated levels of uranium and thorium. This means that reading one for various lengths of time slightly heightens your level of radiation exposure. Find out how much magazines like Playboy are poisoning your body, even if they're not corrupting your mind and polluting your soul.

Whenever we pick up a glossy magazine, we owe a debt of gratitude to Georgia, the state that has a thriving kaolin mining business. Kaolin, once used in the production of porcelain, is a soft clay. When mixed together with wood pulp, it smooths over the gaps between the stringy cellulose fibers, and makes paper smooth and lustrous. Kaolin is especially good for color photos, and used extensively in glossy magazines focusing on image and photography.

It's also good for storing uranium. Uranium and thorium, two radioactive elements, are found in kaolin, and they can't be removed by any process that would let the kaolin remain a practical option for paper manufacturers. So the uranium and thorium come along for the ride, ending up in magazines and high-quality photo paper.

Researchers conducted an experiment to measure the amount of uranium and thorium in the average magazine, and how much exposure a person would get from that magazine over the course of an hour. Magazines were shredded, weighed, and their radiation levels measured and compared against the background level of radiation. The test found that there were about 0.15 to 0.35 picocuries per gram of uranium and 0.3 to 0.6 picocuries per gram of thorium. A 'curie' is a unit of measurement which describes the concentration of radioactive substances in a material by the rate at which they are decaying. A picocurie is a trillionth of a curie.

Here is a graph of the energy given off by a Playboy magazine mysteriously left in the lab.

Overall, the radiation exposure of reading a 500 gram magazine was calculated to be 0.0015 microrem per hour. That is, we pick up about 0.0015 millionths of a rem per hour when we read a magazine. In comparison, the average background radiation is 0.008 millirem, or thousandths of a rem, per hour. Eating a banana is 0.01 thousandth of a rem per hour. So you're probably fine not only with reading Playboy (or Playgirl) magazines, but building your house out of them and maybe eating a couple of them while you're at it. Just don't read them while eating a banana. Apart from the radiation exposure, that's still illegal in most states.

Via Orau, ISU, and Sizes.com.

We still haven't found the Higgs boson, the hypothetical particle that explains why other particles possess mass. But that might not be the only cosmic mystery the Higgs can solve. It could also explain how the universe got its shape.

That's the theory put forward by researchers at Switzerland's École polytechnique fédérale de Lausanne, or EPFL. They argue that the Higgs boson might allow us to account for inflation, the otherwise unexplained process in which the early universe grew by a factor of at least 10^26 in an instant. It's not a universally accepted idea, even among physicists and cosmologists, but it seems to be the best way to account for the uniformity of the modern universe. (For an excellent, comprehensive primer on inflation, check out this post by our own Dr. Dave Goldberg.)

Exactly what caused inflation is still up in the air, and that's where the EPFL physicsts believe the Higgs boson enters the picture:

In its first moments, the Universe was unimaginably dense. Under these conditions, why wouldn't gravity have slowed down its initial expansion? Here's where the Higgs boson enters the game – it can explain the speed and magnitude of the expansion, says Mikhail Shaposhnikov and his team from EPFL's Laboratory of Particle Physics and Cosmology. In this infant Universe, the Higgs, in a condensate phase, would have behaved in a very special way – and in so doing changed the laws of physics. The force of gravity would have been reduced. In this way, physicists can explain how the Universe expanded at such an incredible rate.

Here's where things get really interesting. The researchers found that, as this condensate form of the Higgs boson disappeared and the particles we know today took over, their equations permitted for the existence of a new, massless particle, which they've dubbed the dilaton. This particle is closely related to the Higgs, and shares many of its properties. But the dilaton is only similar to the Higgs - its properties happen to exactly describe what we observe with dark energy, the mysterious property or force that is causing the universe to accelerate its expansion.

The researchers had not set out to explain dark energy when they worked out what role the Higgs boson might have played in the expansion of the universe. Obviously, this is all strictly theoretical - particularly the dilaton - but the fact that their attempt to explain one cosmic mystery happens to also explain another is an encouraging sign that there may well be something to this. These are big claims, of course, and it's doesn't matter how elegant the equations are if we can't find any proof of these particles, but still...this is one hypothesis that's definitely work a closer look.

Via arXiv. Illustrations by EPFL.

One of the strangest and most exotic theories to come out of theoretical physics is that the entire universe is a projection of a two-dimensional shell. But the latest evidence suggests the cosmic hologram really is just a crazy theory.

While the notion of a holographic universe opens itself up to all sorts of fanciful interpretations (we had some fun with the idea a while back), the actual theory is fairly...well, "straightforward" isn't really the word. Basically, certain subsets of string theory tell us that it's possible to encode all the information of a 3D volume onto a 2D structure at its boundary.

By extension, the entire universe might just be the 3D projection of information found on a 2D information structure at the edge of the universe. The 3D hologram that we experience is just how the 2D structure is perceived at macroscopic scales or low energy levels. OK, fine...it's still a pretty wild idea, but what it really speaks to is the basic quantum structure of the universe, and certainly not that our existence is somehow less "real" because of it.

Anyway, the idea picked up some support with the findings of GEO 600, a gravitational wave detector located in Germany. The detector found that, at incredibly small scales, there was actually a certain degree of blurriness in the data, as though we were only looking at the "pixels" being projected onto the hologram from the 2D universe.

But now new results have come in from the European Space Agency's Integral gamma-ray observatory, whose instruments are just as precise as those of the GEO 600. The observatory can measure gamma-ray bursts, and depending on their behavior it can determine whether the universe really does become "grainy" at super-small scales. The observatory has measured an extremely bright gamma-ray burst as it traveled 300 million light-years towards Earth, and the results were unmistakable: there were no signs of blurriness.

What's more, we can be sure that there was no blurriness down to 10^-48 meter. That's ten trillion times smaller than the Planck length, which is considered the fundamental unit of length in quantum mechanics. Indeed, it's not at all clear whether it's even possible for there to be distances shorter than the Planck length, at least not in our current understanding of quantum mechanics.

For its part, GEO 600 had detected quantum fuzziness at scales of 10^-16 meter, which is ten quintillion the size of the Planck length. There's no easy way to reconcile these two results without saying that one or the other was in error, and the burden of proof probably has to be on GEO 600, since it's the more dramatic result. It's possible that some exotic factors may affect the gamma-ray photons that were measured by the observatory so that they don't show signs of quantum fuzziness, but that's probably the least plausible conclusion based on the current evidence.

None of this rules out the holographic universe - if nothing else, the holographic principle is still hugely useful to understanding quantum mechanics. But it looks like, if our universe really is a hologram, then the evidence for that exists on scales so impossibly small that they lay beyond our abilities to probe. So then, it's probably best to leave the cosmic hologram as an interesting idea, and - at least for now - not much more.

Via Discovery News. Image via.

It is my sad duty to tell you that you can. You can now change your name to I.P. Freely. Fear should not keep you from peeing in a pool – just shame.

Most of us have heard, at some point during our childhood, that before we go in the pool there was something we should know. Everyone knew that sometimes people peed in a pool. Knowing that young children often took advantage of this – pool managers put a chemical in pool water that reacted to urine. If someone peed in a pool, they'd be surrounded by a cloud of colored water and publicly shamed. It's such a common belief that some pools put up signs saying that they treated their pool with such chemicals, and it was featured in a movie, Grown Ups, in which four adult men were found out in such a manner.

This is a matter of concern to a concerning amount of people. There are plenty of sites on the internet addressing the idea that there is a compound that changes color when exposed to urine. Is there such a compound? The answer is yes. The problem is, it would react to a lot of different organic chemicals as well. Urea, a compound found in urine, is used in a number of different ways, all of which would lead to angry, embarrassed people in a swimming pool.

Manufactured urea (not harvested from actual urine) is used as a tooth whitening agent, a flavor enhancer in cigarettes, an ingredient in moisturizers and conditioners, and in textile dyeing. That means that a lot of people, upon diving in the pool, would come out with dyed clothes, hands, skin, and mouths. And all of them would complain.

This doesn't stop public pools, swimming clubs, and private owners, from regularly contacting various pool supply companies and asking for the dye to put in their pools. I find this quite heartening. People complain often about the irresponsibility of companies today, but think about it. As soon as someone let loose a cloud in their pool, they'd have to drain it, clean it, and re-fill it. The fact that they're willing to do that rather than let the public immerse themselves in urine is very sweet. The fact that most of the pools would probably be drained full time – is not something we should think about in depth.

Via About.com and Snopes.

The longer you use a computer, the hotter it will get. That seems like just an everyday fact of life, but it might actually be its own law of physics. And, like all phyiscal laws, quantum mechanics apparently violates it.

The original idea was first proposed by physicist Rolf Landauer, who argued that it is a basic principle that, in order to erase one bit of information, you must increase the entropy of the environment by the same or greater amount. Since the simplest way to increase entropy is for heat energy to build up and dissipate, this means erasing a bit of information raises the temperature by one "bit" of heat. That idea has been around for about 50 years, but there's still sharp disagreement among physicists as to whether Landauer actually described a full-on law of physics.

Working from that principle, physicist Vlatko Vedral and his team have figured out how it would interact with quantum mechanics. As you might expect, the results are counterintuitive and deeply strange. Writing about his work in Scientific American, Vedral explains:

Our new paper argues that in quantum physics, you can, in fact, erase information and cool the environment at the same time. For many physicists, this is tantamount to saying that perpetual motion is possible!

Thankfully, like all other apparent violations of basic physical laws, this bit of quantum weirdness isn't actually opening up the doors to perpetual motion. Vedral goes on:

This, luckily for the second law (though not for would-be inventors of perpetual motion machines), is not the case. Landauer's insight is still fine, and erasing information adds entropy to the environment. What saves the second law is that, in quantum physics, entropy can actually be negative. Adding negative entropy is the same as taking entropy away. The key phenomenon behind it is the spookiest of all quantum phenomena, entanglement.

To understand the connection between entanglement and negative entropy we have to go back to Schrödinger's view of entanglement. When two systems are entangled, we have complete information about their joint state, but have no information about their individual states. If we are erasing the state, as a whole we need not generate entropy (since the state has zero entropy), but if we erase subsystems individually, then each will contribute to entropy generation. The difference between the global and local erasing is negative entropy. To rephrase, if we have to erase some information, it helps to know whether this information arises from the entanglement with another system. Then, by invoking the other system in the erasure, we can actually erase and the environment can lose entropy.

For more, check out Vedral's entire article over at Scientific American.

Image via.

If you take two flat mirrors and place them very close together, the virtual particles that pop into existence between the mirrors will actually force them together. But that's nothing compared to when mirrors approach the speed of light.

We've talked about virtual particles before, but for our purposes all we really need to know is that, according to our understanding of quantum mechanics, pairs of particles and their corresponding antiparticles will pop into existence, then almost immediately annihilate each other. These are known as quantum fluctuations.

So how do the mirrors come into it? Basically, if the two mirrors are close enough together, the distance between them actually becomes smaller than the wavelengths of the virtual particles. This in turn creates an imbalance between the vacuum pressure inside the mirrors and that on the outside, creating an attractive force that brings the two mirrors together. This is known as the static Casimir effect, and it was experimentally demonstrated in 1998.

Still, that's downright normal compared to the dynamic Casimir effect. This can only come into play if a mirror is traveling at relativistic speeds, which is roughly speaking 10% of the speed of light or faster. Technology Review's arXiv blog explains what theoretically happens here:

At slow speeds, the sea of virtual particles can easily adapt to the mirror's movement and continue to come into existence in pairs and then disappear as they annihilate each other. But when the speed of the mirror begins to match the the speed of the photons, in other words at relativistic speeds, some photons become separated from their partners and so do not get annihilated. These virtual photons then become real and the mirror begins to produce light.

You'd think that something like this would be impossible to test, considering you need to get a mirror traveling close to the speed of light. But researchers at Sweden's Chalmers University have figured a rather ingenious way around that little conundrum. Again, Technology Review explains:

Instead of a conventional mirror, they've used a transmission line connected to a superconducting quantum interference device or SQUID. Fiddling with the SQUID changes the effective electrical length of the line and this change is equivalent to the movement of an electromagnetic mirror. By modulating the SQUID at GHz rates, the mirror moves back and forth. To get an idea of scale, the transmission line is only 100 micrometres long and the mirror moves over a distance of about a nanometre. But the rate at which it does this means it achieves speeds approaching 5 per cent light speed.

So having perfected their mirror moving technique, all Wilson and co have to do is cool everything down, then sit back and look for photons. Sure enough, they've spotted microwave photons emerging from the moving mirror, just as predicted.

This is, according to the researchers, the first ever observation of the dynamical Casimir effect. Now it's just a question of finding a sufficiently evil application for a light-producing mirror traveling at relativistic speeds. Seriously, something like that should be enough to conquer a small country at the very least.

arXiv via Technology Review.

We assume that snakes kill with venom shot through their fangs, injection style. In fact, most snakes leak poison very slowly. Oddly this technique works quite well, and you can figure out why by considering the physics of ketchup in a bottle.

When a venomous snake bites, it has long fangs to bite far into its prey and push the venom deep into the wound. There the toxin incapacitates the prey and the snake enjoys a good meal. Using that model, most fangs should look like syringes. They should be long, hollow tubes through which venom is pushed. That isn't what researchers found when they started inspecting snake fangs. Only about one in seven venomous snakes had fangs through which they injected poison. Most had grooves in their teeth that poison simply flowed down. Since these snakes are still around, this predatory system has to work, but how exactly do the snakes ensure that the venom is pushed into the flesh of its prey?

One major reason why the grooved teeth work is the high surface tension of snake venom. The molecules in the venom hold on to each other tightly. Molecules along the surface of the venom form a kind of 'skin' that holds the body of liquid together. The suface tension exerts an inward pressure on the main body of liquid, so when the snake bites, and lets its poison drip down its fangs, the surface tension on the drop of venom 'pushes' the main body of venom into the groove on the tooth. The top of the liquid itself forms a kind of third wall.

There's a problem here. If the venom is so tough that it forms a 'third wall' all on its own, it shouldn't go into the prey animal's tissue at all. It should just sit there in the groove, held together by its on cohesion. The venom has a fix for that. It is one of many deliciously-named thixotropic liquids. Ketchup is another. The running joke about how ketchup stays stuck in the bottle until a certain amount of shaking makes it flow so fast it floods the top of a burger has its foundation in fact. Thixotropic liquids behave like gels or foams, hanging loosely together, until a sideways force is applied. Sometimes it's rhythmic pounding on the side of a bottle. Sometimes it's fast vibrations. Sometimes it's the movement of prey, or the natural absorbtion of the prey's muscle tissue. When a sideways, or vibrational, force is applied to a thixotropic liquid, it flows fast. So the snake's venom holds together until it gets into the prey, and then gushes into the surrounding tissue.

And clearly, ketchup is made from snake venom.

Via Physical Review Letters and Newton Ask a Scientist.

Photo via Shutterstock.

Queen bees are much larger than worker bees, and live years longer, for one reason. They gorge on a sugary protein called "royal jelly." Now a scientist has made ultra-large flies using royal jelly too. Are humans next?

Sadly, it doesn't look like tomorrow we'll be creating giant women who live for hundreds of years by feeding human babies on royal jelly. But a biotechnology researcher in Japan, Masaki Kamakura, has discovered how one of the active ingredients in royal jelly - a protein called royalactin - makes queen bees. And he's done it by turning female flies into queens as well. It's a weird and fascinating breakthrough.

This week in the journal Nature, Kamakura explains how he figured out that royalactin is what causes two bees with identical DNA to turn into a queen or a worker. He did it giving royal jelly to fruitfly larva, to see whether this distant relative of the bee would also undergo a queenlike transformation. To his surprise, it did. He wrote:

[Fruitflies] reared with medium containing 20% royal jelly, 8% yeast and 10% D-glucose had an increase in body size (body weight and body length) and fecundity, and had extended lifespan and shortened developmental time compared to flies reared with control medium or casein.

The scientist was able to take advantage of the fact that scientists have experimented extensively with fruitfly genetics. It was therefore much easier to isolate the genes that were triggered by the royalactin, and figure out how the substance makes some bees into queens. Becoming a queen pretty much transforms an ordinary worker bee into a super being - queens grow into enormous adults at an accelerated rate, live 20 times longer than their counterparts, and are hyperfertile.

In Nature's The Great Beyond blog, Ewan Callaway reported on the finding:

"Finding the active components of royal jelly that are important for queen development has been kind of a holy grail of insect research for decades," says Gro Admam, an entomologist at Arizona State University in Tempe, who was not involved in the new paper.

All newly hatched honeybee larvae gorge on the heady mix of proteins, fats, sugars and vitamins. After three days, though, soon-to-be worker bees switch to a diet of honey, pollen and water, while the heirs to throne continue to eat royal jelly. This shift underpins the eusocial lifestyle of honeybees, in which sterile workers support a hyper-fertile queen, who grows much larger and lives about 20 times longer than workers.

Research from the 1960s suggested that royal jelly contained a potent neurochemical, while a 1972 paper highlighted developmental hormones. More recently, scientists identified a set of Major Royal Jelly Proteins, potentially involved in making queens . . . [In Kamakura's work] mutant flies hinted that royalactin was recognized by a protein called EGFR, which senses hormones called epidermal growth factors. Flies lacking EGFR or some of the proteins it communicates with got none of the growth or fertility benefits of royal jelly or royalactin, Kamakura found. Reducing the levels of the growth factor-sensing protein in honey bee larvae, meanwhile, prevented royal jelly-fed larvae from becoming queens.

This is the first time a researcher has used royal jelly to create queenlike traits in another insect. Knowing how royalactin works could shed light on the evolution of bees' social lives, with castes and division of labor.

And hopefully, we're closer to inventing a royal jelly for humans, something we could feed children that would help them live twenty times longer than they would otherwise.

Read the full article via Nature

Some scientists believe that, as the universe gets older and larger, it adds more dimensions. Cute theory. But how does this help solve pressing questions of of physics? And how can it be tested?

One of the crazier theories of physics is the idea of Vanishing Dimensions. It should, technically, be the idea of Appearing Dimensions, since it proposes that, as the universe aged and grew, it added more and more dimensions. What's more, the amount of dimensions we see depend on the amount of space we're studying. Large spaces have three or more dimensions, while smaller ones have two, or even one.

Although the idea appears preposterous, it would explain a few things. For one thing, it might explain why the universe seems to be expanding at a higher and higher rate. Physics are baffled by the acceleration of this expansion, but if the universe is adding dimensions as it gets bigger and older, that may explain the change in expansion. It may it also explain why the mathematics of quantum mechanics and of relativity don't seem to work together. If relativity is generally applied to large spaces and large objects, while quantum mechanics applies to small spaces and small objects - they could be describing universes with different numbers of dimensions.

The theory also points the the idea that the early universe was a point, that expanded into a one-dimensional line, that then expanded into a two-dimensional plane, and at last popped out the third dimension that we happily move through today.

Although the theory could fill in some blanks for physics if it proves true - it is hard to prove true. A 'dimensionometer' has not yet been developed. How would anyone figure out if small pieces of the universe lack dimensions? Apparently, gravity can only work in three dimensions. There are plans (although they are only intermittently funded) to build gigantic telescopes that observe the gravity of the universe. Since gravity, like light, takes time to move through the universe, the farther out astronomers look, the farther back in time they see. Look far enough back, back to when the universe was one dimensional, and gravity should disappear.

And the universe will officially become even weirder.

Via Physical Review Letters.

Photograph by optimarc/Shutterstock

Recently scientists staged a demonstration in which flesh-eating bacteria died off in droves when placed on a copper surface. Find out why copper engages in bactericide.

Hospitals are necessary and efficient institutions meant to gather and train a variety of experts in order to serve any sick person who comes in. They're also festering pits of infection. It's not really their fault. They just have a huge number of very sick people, all of whom are visited by medical staff, administrative personnel, and facilities staff who continue to move through the building, collecting bugs as they go. Though hospitals institute hygienic policies, they remain one of the places where people are at the highest risk for infection. In fact, one of the major places that people pick up MRSA, or flesh-eating bacteria, is in a hospital.

MRSA is notoriously hard to kill, and often requires surgery and stints in hyperbaric chambers. This is why a demonstration of MRSA dying off on a copper was so dramatic. Most instruments in hospitals are stainless steel - a material that does not require much upkeep, is strong, and is easy to shape. The anti-microbial properties of copper make it a tempting alternative. Simple dry copper, and certain copper alloys, kill of bacteria after a few minutes of contact.

Copper's attack on cells is not confined to one approach. It's a renaissance killer, and it unleashes a multifaceted wave of destruction. First, it storms the cell. Cells maintain a certain voltage difference between their bodies and the outside world. The cell wall keeps this difference in electrical potential going. Copper manages to let the electrical energy in the cell flow through to the outside world, short circuiting the cell and weakening the wall. Copper ions also tend to react with oxygen (this causes the green patina that appears on the surface of copper pennies or the Statue of Liberty). If it reacts with oxygen while in contact with certain cell proteins or fatty acids, the whole thing turns into a version of the green patina and the cell wall is 'rusted' away.

Once the cell wall is destroyed, there's free flow into and out of the cell. Potassium and glutamate tend to flow out, draining the cell of needed components. Copper ions flow in. They bind to enzymes in the cell, causing the enzymes to become inactive, and disrupting nutrient processing and cell recreation. The cell is usually dead in minutes.

Various organizations, usually organizations with a lot of copper to sell, are pushing to have things like hand rails, beds, and doorknobs resurfaced with copper or copper alloys, especially in hospitals. Since copper is harmless to humans, it would be a painless way to reduce infections. Although copper tarnishes, it still manages to kill bacteria, and is sometimes shown to kill more bacteria if it looks a little grody. Alternately, doctors, nurses, and staffers could just try to handle a lot of pre-1982 pennies. Those who want to see MRSA die on copper can check out a video of it here.

Via Science Daily, Antimicrobial Copper times two, and Antimicrobial Touch Surface.

The Western fence lizard was once believed to be our best defense against lyme disease. That's because ticks carry lyme disease, but lizards carry a lot of ticks. In fact, ticks are so enamored of lizard blood that they basically act as a buffer zone between humans and lyme disease - as long as the Western fence lizard is around, ticks will always prefer its cold blood to ours. So what happens if the lizards die out or go away? Are we facing a lyme disease catastrophe? Some UC Berkeley researchers decided to find out.

Led by biologist Andrea Swei, the group rounded up lizards in 14 different regions of Marin County, California. They wanted to see where the ticks would wind up if they didn't have lizard snacks. Would they turn to other animals, or people? What they discovered surprised them.

According to a release about the group's findings, published yesterday in the Proceedings of the Royal Society B:

From March to April 2008, before tick season went into full swing, the researchers captured and removed 447 lizards from six plots – three at each site – and left the remaining plots unaltered as controls. The lizards that had been captured were marked [with liquid paper] before being relocated so the researchers could determine whether any wandered back into their old haunts.

After the lizards were removed, the researchers spent the following month trapping other mammals known to harbor ticks – particularly woodrats (Neotoma fuscipes) and deer mice (Peromyscus maniculatus) – to determine whether they bore an uptick in ticks as a result of the lizards' absence. The researchers also checked for differences between control and experimental plots in the abundance of host-seeking ticks by systematically dragging a large white flannel cloth over the ground.

The researchers found that in plots where the lizards had been removed, ticks turned to the female woodrat as their next favorite host. On average, each female woodrat got an extra five ticks for company when the lizards disappeared.

However, the researchers found that 95 percent of the ticks that no longer had lizard blood to feast on failed to latch on to another host.

"One of the goals of our study is to tease apart the role these lizards play in Lyme disease ecology," said Swei, who is now a post-doctoral associate at the Cary Institute of Ecosystem Studies in New York. "It was assumed that these lizards played an important role in reducing Lyme disease risk. Our study shows that it's more complicated than that."

So the takeaway message here is that the lizards were never really on our side. They weren't trying to protect us from ticks at all. And ticks are a lot more faithful to lizards than we ever knew.

You can read the full scientific article in the Proceedings of the Royal Society B.

Using a new method of observing microscopic changes in a material's behavior, scientists have spotted very cool properties in a water-methanol compound called methanol monohydrate. These crystals get smaller when warmed, but when you apply pressure to them (i.e., poke them), they expand outwards. This material is thought to be a major component of the icy moons of our solar system. Get ready for methanol monohydrate mines on the moons of Saturn.

Anyone who's seen enough old Sesame Street episodes or been to enough Renaissance Fairs knows that when glass gets hot enough, it turns to liquid. Applied heat pumps energy into the solid pieces of glass, getting their molecules jiggling. As the heat dissipates, the glass becomes cool and solidifies again.

Most of the time, not many interesting things happen once a substance gets below the temperature required for solification. Its atoms are bound to one another, and without the indroduction of some kind of energy, they'll stay that way. Glass, it turns out, is the exception. Once it gets close to absolute zero, it melts again.

But what could make that happen? The atoms in glass chilled to near-absolute zero have almost no energy, so they can't be jiggling fast enough to tear apart from each other. And yet, on paper and in computer simulations, glass returned to a liquid form when brought close enough to absolute zero.

The wild card turned out to be quantum mechanics. Once the atoms of glass became still enough, they stopped acting like particles and instead acted like waves. The wave-like atoms now were able to flow, moving through spaces too small for particles to get through. This motion, and this ability to fit through small spaces, causes ultra-cold glass to melt into a liquid. No word yet if this works on the T-1000.

Via Wired and Nature Physics.

Quantum entanglement says that two particles can become intertwined so that they always share the same properties, even if they're separated in space. Now it seems particles can be entangled in time, too. Who's ready for some serious quantum weirdness?

Of all the ideas in modern physics, quantum entanglement is a serious contender for the absolute strangest. Basically, entangled particles share all their quantum properties, even if they are separated by massive distances in space. The really odd part is that any changes made to the properties of one particle will instantly occur in the other particle. There are some subtle reasons why this doesn't actually violate the speed of light, but here's the short version: this is all very, very bizarre.

But all experiments in quantum entanglement have focused exclusively on spatial entanglement, because seriously...isn't this already weird enough? Apparently not for physicists S. Jay Olson and Timothy C. Ralph of Australia's University of Queensland, who have figured out a series of thought experiments about how to entangle particles across time.

Now, what the hell does that mean? Well, Olson explains:

"Essentially, a detector in the past is able to ‘capture' some information on the state of the quantum field in the past, and carry it forward in time to the future — this is information that would ordinarily escape to a distant region of spacetime at the speed of light. When another detector then captures information on the state of the field in the future at the same spatial location, the two detectors can then be compared side-by-side to see if their state has become entangled in the usual sense that people are familiar with — and we find that indeed they should be entangled. This process thus takes a seemingly exotic, new concept (timelike entanglement in the field) and converts it into a familiar one (standard entanglement of two detectors at a given time in the future)."

That may still be a bit confusing, so think about it this way. The detectors are basically taking on the properties of their particles - if they share the same properties, then the particles themselves are entangled. The first, "past" detector stores one set of quantum properties, and then the second, "future" detector measures a new set of properties at the same location as the first. The two sets of quantum properties are affecting each other just like spatially entangled particles share the same properties, but now it's happening across time instead. Once the two detectors are brought together in time, the entanglement becomes the more normal (well, relatively speaking) sort of spatial entanglement.

This may seem difficult to comprehend - I know I'm struggling with it - but that's because we're accustomed to temporal events always being completely independent of one another. Both types of entanglement are counter-intuitive, to be sure, but it's easier for us to imagine particles sharing properties in different parts of space than it is different parts of time because we ourselves move through space so easily. And yet, from a physics perspective, there isn't all that much of a difference between space and time, and certainly not enough to rule out temporal entanglement.

Now, this is all still just hypothetical for the time being, but there is a theoretical basis for this and it may soon be possible to probe these ideas further with some experiments. Still, if you're up for a bit of extra credit weirdness, here's Olson and Ralph's thought experiment for teleportation through time. Let's say you want to move a quantum state, or qubit, through time. You'll need one detector coupled to a field in the "past" and another coupled to the same field in the "future." The first detector stores the information on the qubit and generates some data on how the qubit can be found again. The qubit is then teleported through time, effectively skipping the period in between the past and future detectors.

The first detector is removed and the second detector is put in precisely the same place, keeping the spatial symmetry in tact. The second detector eventually receives the necessary information from the first, and then it uses this to bring the qubit back, reconstructing it in the future. There's a weird time symmetry to all this - let's say the qubit is teleported at 12:00 and the first detector gather its information at 11:45. That fifteen-minute gap must exist in both direction, and it's impossible to reconstruct the qubit until 12:15 rolls around.

Obviously, these are all deeply strange, epically counter-intuitive ideas right at the bleeding edge of what modern physics can conceptualize. But it's also very awesome. And as soon as I even begin to understand it, I'm sure it'll get even more awesome.

[arXiv]

The Living Earth Simulator is quite possibly the most ambitious computer project ever undertaken. This all-encompassing simulation will collect all the data in the entire world, to predict everything from the next major disease outbreak to the next financial crisis.

The Living Earth Simulator could do for our modern world what the Large Hadron Collider has done for the early universe, says project chair Dr. Dirk Helbing. He calls the LES a "knowledge accelerator" that can collide different fields of knowledge to produce a far greater understanding of what's going on in the world around us.

Such a program, he says, could help show us the next epidemic before it starts, illuminate better ways to deal with climate change, and predict when the next recession will hit. According to Dr. Helbing, the answers to all these mysteries can be found by examining the sum total of human activity:

"Many problems we have today - including social and economic instabilities, wars, disease spreading - are related to human behaviour, but there is apparently a serious lack of understanding regarding how society and the economy work. Revealing the hidden laws and processes underlying societies constitutes the most pressing scientific grand challenge of our century."

So where would they get all the data from? Lots of different organizations are already compiling massive amounts of data, and these would help feed into the Living Earth Simulator. Possible sources would include NASA's Planetary Skin project, which tracks climate data on every corner of the globe, as well as more everyday sites like Google Maps and, yes, Wikipedia. Helbing and his team also plan to incorporate medical records, the latest financial information, and, most frighteningly of all, everything that's going on in the world of social media.

Of course, once all that data is together, there's still the question of what to do with any of it. Helbing says this will require cooperation between social scientists and computer scientists to create the rules and programming that the LES needs to interpret the data and create an accurate model of the Earth as it is today. We've only now got the technology advanced enough to pull off such an endeavor, and it will still be very tricky.

Part of the solution, Dr. Helbing explains, is the rise of semantic web technology. This simple but powerful concept makes a computer see information not just as a set of numbers but as specific data in a specific context, meaning computers will be able to tell the difference between the seemingly random numbers making up, say, financial markets and weather reports in much the same way humans can.

An obvious question to ask is just how much the LES will be able to learn about particular people. On this point, Helbing argues that the vastness of the project should protect everyone's privacy, as the LES's aggregative strips out all individual data in an effort to create an overall picture.

Once you collect all the data and program the simulator, actually running the LES is relatively simple. Yes, the project will need huge banks of supercomputers to run the entire program, but the processing power required isn't beyond what we're currently capable of. Computer expert Pete Warden says that, in all probability, we do have the processing power to handle what the LES requires. That said, he's skeptical about whether the LES could actually produce useful results:

"Economics and sociology have consistently failed to produce theories with strong predictive powers over the last century, despite lots of data gathering. I'm sceptical that larger data sets will mark a big change. It's not that we don't know enough about a lot of the problems the world faces, from climate change to extreme poverty, it's that we don't take any action on the information we do have."

To this point, Dr. Helbing argues that the LES will offer predictive far in advance of our previous models, as it would be able to see global recessions and disease outbreaks coming before they really get started. It's a bold claim, and we won't know for sure what the real capabilities of the LES are until the day that it's up and running.

[via BBC News; check out Gizmodo's coverage here]

General relativity and quantum mechanics are the twin foundations of modern physics, but there's a problem: they're mutually exclusive, at least according to our current understanding. A new model using loop quantum gravity might have the beginnings of a solution.

Relativity holds that reality is uniquely determined and always measurable, whereas quantum mechanics tells us that uncertainty and immeasurable values are woven into the very fabric of nature. Both of these facts have been backed up by countless experiments. So what's the solution?

Physicists are still hard at work at an answer to that question - an answer that might finally lead to the long sought after grand unified theory - but a team from Poland's University of Warsaw just might have gotten us a step closer. They have developed a new model of quantum gravity (more on that in a moment) that appears able to explain how classical space-time emerged from the quantum world, describes the full theory of general relativity, and is completely mathematically consistent.

To understand why this matters, it helps to go back to the beginnings of the universe. In general, from a purely empirical point of view, it doesn't really matter that much that relativity and quantum mechanics are incompatible - the former is used to measure extremely massive things, while the latter is used to measure extremely tiny things. The math only starts to break down when you consider things that are both extremely massive and extremely tiny. Black holes are the best example of this in the modern universe, but our entire universe was once both massive and tiny, in the first few moments after the Big Bang.

That means that we're unable to construct a working mathematical model for the earliest universe. At a certain critical point of density, the relativistic effects of gravity and the quantum effects of subatomic forces start to commingle, making it impossible to calculate the universe's origins any further and giving physicists nothing but nonsensical infinities. Currently, the most sensible assumption is that these forces do somehow merge in a way we can't currently calculate and, if we were to work back far enough, take us back to the Big Bang.

But that isn't the only possibility. For instance, the theory put forward by the University of Warsaw physicists suggests their particular combination of quantum and relativistic forces - quantum gravity, so to speak - would keep matter energy density from going above a certain value. If that sets an upper limit for density, then our universe didn't explode from a singularity, as the Big Bang holds.

Rather, our universe came from another, contracting cosmos that had been collapsing in on itself. Once it reached the critical density, it exploded back out, forming our universe in a Big Bounce. That said, this idea isn't supported by the full theory because the math isn't advanced enough yet to say either way - this is just an idea put forward using a highly simplified version of the theory.

Still, one possible way to knit gravity and the quantum world together is with something called loop quantum gravity (LQG), which is what this new model uses. The basic premise of LQG is that all of space is actually weaved from tiny one-dimensional threads. The scale of these things is unimaginably tiny: a square centimeter's worth of space would contain 10^66 threads.

The Warsaw physicists used this as their starting point and then added two theories. One was a gravitational field, as gravity creates the entire geometry of space-time in general relativity. The other was a scalar field, which is essentially a useful mathematical tool in which coordinate-independent values are assigned to every point in space so that any two observers will be able to agree on the value of a given point, regardless of their own locations.

Their new model suggests that time itself emerges from the interrelation of the gravitational and scalar fields. Professor Jerzy Lewandowski explains:

"We pose the question about the shape of space at a given value of the scalar field and Einstein's quantum equations provide the answer. It is worthy of note that time is nonexistent at the beginning of the model. Nothing happens. Action and dynamics appear as the interrelation between the fields when we begin to pose questions about how one object relates to another."

This is a breakthrough. Earlier models of the evolution of the universe were based on just general relativity, and so assumed the gravitational field at different points of the universe was more or less identical. The introduction of the scalar field, however, allows gravity to be quantized and to vary from point to point, getting us closer to an understanding of quantum gravity. This is the first such model that also manages to be mathematically consistent.

Still, this is only a first, very tentative step. There's still a lot we don't know about the specific values at play here, and so this only really offers the rough skeleton of a framework. That said, this provides scientists a chance to test out ideas and theories of the earliest universe with a model that, while very basic, does manage to incorporate quantum gravity. Lewandowski explains what they want to do next, which includes trying to figure out whether the Big Bounce really is a feature of their model:

"We have developed a certain theoretical machinery. We may begin to ply it with questions and it will provide the answers. In the future, we will try to include in the model further fields of the Standard Model of elementary particles. We are curious ourselves to find out what will happen.

[arXiv; top image by slobo777]

String theory is one of the more popular candidates to combine quantum mechanics and relativity into a grand unified theory. But it had remained completely untestable until recent experiments at the Large Hadron Collider. The early results don't look good.

A few years ago, a group of physicists came up with an ingenious way to test for the existence of hidden dimensions, a key aspect of many string theory models. Basically, the experiment rests upon the existence of micro black holes, objects tinier than an atomic nucleus that could theoretically be produced by smashing together a pair of protons at tremendously high velocities.

This micro black hole would be very unstable and quickly decay, releasing lots of different subatomic particles. The physicists figured out the specific combinations of particles that would be created if the universe has 10, 11, or even more dimensions. The hope was that the Large Hadron Collider would be able to produce the massive energies required to create these micro black holes.

Well, they ran the experiment, and the results are less than encouraging. The LHC has completed an extensive search for these objects in high-energy proton collisions, and no evidence at all turned up for micro black holes between 3.5 and 4.5 tera-electron-volts. That's a massive energy level and pretty much the upper limit of what we can currently test. This more or less rules out versions of string theory that includes micro black holes at those energies.

Now, let's back up a bit. This isn't good news for string theorists, but it doesn't invalidate string theory either. The original idea for this experiment was always a bit of a long shot, more an attempt to come up with something - anything - that could be used to test aspects of string theory using today's technology.

Researchers hoped to find certain exotic phenomena that would likely exist in a world governed by string theory. Even a few small things can throw this off - the micro black holes might still exist, but they might be larger than the curvature of the hidden dimensions, which would mean they remain unaffected by the extra dimensions. Or it might be even simpler: the micro black holes just can't be found at these energy levels, and we need the next generation Hadron Collider - or even the one after that - to detect them.

String theory definitely lost this particular battle. But this setback isn't the end of the line - it just means the search for a grand unified theory won't be getting any easier. We probably shouldn't have expected anything else.

[CERN via Slashdot]

Hiding in the shadows between the colors we see everyday are weird, impossible shades, colors that you shouldn't be able to see and generally don't...unless you know how. Here's a simple guide to seeing impossible and imaginary colors.

Understanding a little about how humans perceive color is crucial to seeing impossible colors. Our eyes use something called opponent process to work more efficiently. This plays upon the fact that the eye's primary light receptors, the cones, have certain overlaps in what light wavelengths they can perceive. To save energy, our eyes measure the differences between the responses of various cones rather than figuring out each cone's individual response.

We long ago found out that there are three opponent channels: red vs. green, blue vs. yellow, and black vs. white. (Technically, black and white aren't colors, and their opponent process has more to do with brightness than anything else.) Now, let's say you stare right at the bluest object you've ever seen. Your cones that primary perceive the blue wavelengths are going to be excited, while the cones responsible for yellow will be inhibited. If you then switched to looking at the yellowest thing you've ever seen, the exact opposite would happen.

It probably isn't all that shocking to point out the cones can't be excited and inhibited at the same time. That means that it's impossible to see an object that's simultaneously blue and yellow or red and green. I'm not talking about what happens when you mix those colors and then look at them - obviously, you'd get green and a sort of murky brown if you did that. No, what I'm talking about here are colors that are equal parts blue and yellow at the exact same time. Can you imagine that? Well, you shouldn't be able to, because that's an impossible color.

This might all seem a bit abstract, but there's some evidence backing up the existence of such colors. A 1983 experiment featured a special machine which separated the fields of vision of the test subject's eyes. One eye would see a red screen, while the other would see a green screen. Given time, the colors would mix together, but the mixing only occurred in the brain. Without the eye there to mediate the mixing, red and green didn't become brown - they became a new color, a reddish-green color that none of the test subjects had ever seen before, and that includes an artist with an extensive knowledge of different hues and shades.

Admittedly, the methodology of that experiment has since been criticized, and many vision researchers say impossible colors are called that for a reason – they really are impossible. There are, to be sure, a lot of alternative explanations for the colors the people saw: they were just intermediate colors between the two, the experimenters hadn't properly controlled for luminance and that threw off the results, or the test subjects were really just see red, then green, then red, and so on, and never actually viewing them simultaneously.

These are all fair points. However, if I may make a counterpoint, you're ruining all the fun, vision experts. Sure, impossible colors might actually be impossible, but that doesn't change the fact that test subjects saw colors they had never seen before. Impossible colors might not exist, but if it's possible to fool our brains into thinking they do, then I'd say that's still pretty awesome.

This is one of the least scientific viewpoints I've ever put forward, and I'm not exactly proud of it, but hey...impossible colors are cool. Now relax each eye on these two plus signs and see if you can't make some impossible colors appear. Let your eyes cross so that the two pluses are right on top of each other. I'll say right now that not everyone is going to be able to see these weird colors - I'm almost certain that I can't - but I'd still say it's worth a try.

I'd be remiss if I didn't also mention imaginary colors. These are colors that cannot be produced in the physical light spectrum, and yet it's possible to derive them mathematically. The easiest way to understand what an imaginary color is would be to think about the three wavelengths of cones - short, medium, and long. Like I said when talking about the imaginary colors, there's an overlap in the responses of these different wavelengths.

But what if you had a color that only created a response in the medium wavelengths? In real life, this can't happen, as anything that excites the medium wavelengths is going to excite one or both of the other wavelengths. But if you did have a color that only excited the medium, green wavelengths while leave the other two types alone, then you'd be able to see a color greener than any real green.

So that's the theory - here's how you do it. Again, you've to be smart about your opponent processes. If you want to see an imaginary green, you need to find an example of heavily saturated red and one of a heavily saturated green. Stare at the red color for as long as you can, then switch to looking at the green. The red receptors have become too fatigued to do their job and be inhibited by the green color. That means your green receptors are getting excited with nothing to counterbalance them. The result is the greenest color you've ever seen, one that can't exist in the physical world.

Again, this might all seem a bit out there, but America's most lovable evil geniuses have known about this for years. Walt Disney World took advantage of this effect in their design of the EPCOT park, making the pavements a particular shade of pink that tires out the red receptors and forces the park's grass to look greener than it really is. On second thought, I'm not sure that makes this seem any less out there.

For more, check out "Impossible" Colors: See Hues That Can't Exist (Scientific American).

Positronium is a particle created when you bind together an electron and its antimatter counterpart, the positron. It doesn't interact with other atoms in the way we would expect, and this discovery could help us solve the universe's biggest mysteries.

Positronium is sort of like a hydrogen atom, except if you took away the lone proton in the nucleus and replace it with a positron. Because electrons - and, by extension, positrons - are only 1/1836 the mass of a proton, that means positronium particles are much less massive than their hydrogen counterparts. The particle is a common byproduct of the interaction between regular matter and positrons. It's an unstable particle, only remaining together for an average of 142 nanoseconds before decaying into two gamma ray particles.

During their very short lifetimes, however, it's possible to probe some of their properties and characteristics, and that's what researchers at University College London recently attempted. They tried a scattering experiment, in which they sent streams of positronium particles at different atoms and molecules and measured how they interacted. Because positronium is a hybrid of an electron and positron, they expected the particle to act in a way that was some sort of average of these two.

But that isn't what they found. Instead, positronium acted precisely the same as an electron would. That doesn't make much sense - electrons are negatively charged, while positronium is neutral, and it's obviously twice the mass of a lone electron. In some weird way, the effects of the positron's presence seems to be cloaked so that only the electron half of the positronium interacts with other matter. Of course, "in some weird way" is a nice way of saying we currently have no idea why the hell this is happening, and there's a lot of theoretical work that will be needed to explain this effect.

But doesn't mean we can't enjoy the practical benefits of this finding. The discovery of positronium's electron-like behavior could make it the best candidate to create a Bose-Einstein condensate, a special, ultra-cold form of matter in which particles move so slowly that it's possible to observe quantum effects on a much larger scale than is normally possible. Bose-Einstein condensates of various atoms have been created in the last 15 years, but a positronium condensate could have amazing new applications.

This goes back to a study earlier this year in which researchers at UC Riverside managed to polarize the spin of positronium atoms, which would also ease the creation of a Bose-Einstein condensate. At the time, lead researchers Allen Mills and David Cassidy explained the importance of such a condensate:

Mills: "There are fundamental processes that can be looked at in new ways when you have matter in the BEC state. Having Bose-condensed atoms makes it easier to probe the way they interact under certain conditions. Moreover, to have motionless positronium atoms is an important aspect for making something called a gamma ray laser, which could have military and numerous scientific applications."

Cassidy: "The eventual production of a positronium condensate could help us understand why the universe is made of matter and not antimatter or just pure energy. It could also one day help us measure the gravitational interaction of antimatter with matter. At present, nobody knows for sure if antimatter falls up or down."

These are the sorts of cosmic riddles a positronium Bose-Einstein condensate could help us uncover, and the discovery that positronium likes to impersonate electrons should help us create this exotic form of matter. Besides, what could go wrong when creating something with a name as awesome as "gamma ray laser"? Nothing, that's what.

[Science]

Nitroglycerin destroys lives by exploding, and saves them by stopping heart problems. How can it do both?

Most moviegoers have watched a scene or two where nitroglycerin has been used to blow the doors off of a bank vault. They've also seen scenes when a character with chest pains is urged to take their nitroglycerin. Hollywood science isn't real science, but nitroglycerin is used for both. This doesn't seem to make sense. If nitroglycerin is an explosive, why don't people's hearts explode out of their chests like an alien baby when they take it?

For one thing, the two come in different forms. Although solid nitroglycerin can explode, it takes a lot to do it. Nitroglycerin is a wad of carbon, nitrogen, hydrogen and oxygen. In some forms it's stable. In liquid form, it is emphatically not. When it is in this form, it doesn't need real heat. A good physical knock will get it to tumble over like blocks into carbon dioxide and water, with some nitrogen and oxygen gas floating around. During its tumble, it releases a lot of energy, which is where the bang comes from.

Nitroglycerin in solid form is a lot more stable. So stable that it was possible to include it in the mass manufacturing of dynamite. It was during that time that factory workers noticed a strange thing. Whenever they came into the factories, those with pains in their chest felt those pains subside. (This being the eighteen hundreds, any humanitarian consideration for factory workers was strictly forbidden – so the factory owners followed lopped off their noses or followed them home and beat their children or something.)

In pill form, nitroglycerin is no longer one good shake away from blowing itself apart. The body, clever little devil that it is, shifts the nitroglycerin molecules around gently until they form nitric oxide. Nitric oxide is a kind of muscle relaxant. Even blood vessels are surrounded by muscles, and when these muscles flex, they constrict the vessels enough that either less blood reaches its destination or the heart works harder, or both. Nitric oxide makes those muscles relax, and lets blood flow easily through the body. And there is no bang involved.

Via How Stuff Works and Straight Dope.