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    Just getting to the center of the Earth and surviving is impossible. The Earth's core is about 9,000°F-as hot as the sun's surface-and would instantly roast anyone who found himself there. Then there's the pressure, which can reach roughly three million times that on the Earth's surface and would crush you. But let's not sweat the details. Once you arrive in the center of the Earth, the physics gets really interesting.

    Understanding gravity, the force of attraction between objects, is going to be key to wrapping your head around what is about to be a bizarre situation. The strength of gravitational attraction is determined by an object's mass and how close it is to another (more mass and closer together means increased force). The only gravity strong enough for us to feel comes from the Earth's mass, which is why we feel a downward pull on the surface.

    At the center of the Earth, the situation is different. Because Earth is nearly spherical, the gravitational forces from all the surrounding mass counteract one another. In the center, "you have equal pulls from all directions," says Geza Gyuk, the director of astronomy at the Adler Planetarium in Chicago. "You'd be weightless," free-floating.

    But what would happen if you tried to get out of the center by, say, climbing up a very long ladder that ends in Los Angeles? (For clarity's sake, let's assume that the Earth is uniformly dense. It isn't, but the general trend described here still holds.) At the center, the gravity from the mass beneath your feet all the way to the other side of the Earth, the Indian Ocean, will be "pulling" you down, even as the mass above your head is "pulling" you up, toward L.A. After climbing a few rungs, the total pull you feel down to the Indian Ocean will still be nearly zero. You will still feel almost weightless. But as you climb, there will be less and less mass above, and more and more below. The pull toward the core will feel greater and greater, and you will feel less and less weightless, until you are standing on the Earth's surface, staring at the Hollywood sign, feeling heavy again.

    This article originally appeared in the March 2011 issue of Popular Science magazine.


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    Rendered Cloth

    Materials pictured: On the top row, from left to right, linen plain, silk crepe de chine, the front side of polyester satin charmeuse fabric, and the back side of the polyester satin charmeuse. On bottom, silk-shot fabric, velvet, an imaginary fabric made of silk and polyester threads with a shantung weaving pattern, and an imaginary fabric with asymmetric peaks, done in a mirror-like way.

    Iman Sadeghi et. al., Jacobs School of Engineering/UC San Diego

    A new technique makes for some very comfy-looking pillows, which could be useful in video games and animation.

    It's complicated for artists and designers to replicate how light plays off the folds of cloth or fabric. Some research has already gone into how to more accurately and efficiently reproduce those materials in computer renderings, and now a computer-sci team is suggesting a different way--and the results don't look half-bad.

    Google software engineer Iman Sadeghi previously worked on a system for rendering hair in Disney's "Tangled" (which, the trailer confirms to me, featured a lot of hair). Now Sadeghi is turning his attention to the similarly problematic cloth.

    Basically, the system works by breaking down the cloth to the level of individual threads, modeling how each thread reflects light. Then, based on how those threads are stitched together in a material (velvet is different than polyester, and reflects light differently), the program simulates the cloth. Since the process is super-granular, the researchers say they can simulate any type of cloth--even if it doesn't really exist. (Silk plus polyester threaded with a shantung pattern? Sure!) To make that possible, the team examined threads under a microscope, examining and measuring how different materials and patterns reflected light.

    If you're technically minded, you can check out the details of the process here. Otherwise, enjoy these shiny pillows.


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    Martha Stewart, The Exception Rather Than The Rule

    nrkbeta via Wikimedia Commons

    They're less likely to be recruited to join in on a conspiracy, and when they do, they make a whole lot less money.

    Even in crime, women are still bumping up against a glass ceiling. Women are less likely to be a part of conspiracies to commit corporate fraud, and when do commit fraud, they tend to receive less money than their male counterparts, according to a study in the American Sociological Review.

    The study found that in 83 cases of corporate fraud registered with the Department of Justice between 2002 and 2009, three-fourths were entirely male conspiracies. None were all-female---the Spice Girls of corporate fraud have yet to take action, I guess. In frauds where women were involved, for the most part they played more minor roles, and received far less money.

    More than half of women involved in corporate fraud made little or no money, compared to the 26 percent of men who snagged $500,000 to $999,000 from the scheme and the 33 percent who made more than $1 million. Come on ladies, it's the 21st century. Lean in to financial crime already!

    "Women are less likely to be recruited as co-conspirators in male-orchestrated schemes and less likely to be able to recruit co-offenders should they wish to initiate a corporate fraud," lead author Darrell Steffensmeier, a professor of sociology and criminology at Penn State University, said in a press statement. "The glass ceiling effect for involvement in corporate corruption is likely as great or greater than the ceiling that keeps women from climbing the corporate ladder."


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    The Shining

    Warner Bros.

    A study of British "family annihilators" reveals some macabre data.

    In what must be one of the darkest research projects we've covered, a British team has studied 32 years' worth of "family annihilator" cases, where one member of a family murders multiple others. Some patterns emerge from the 71 cases they found.

    For one, the killers were overwhelmingly male: 59 of the subjects. Of those, more than half were in their thirties. About 20 percent of the killing happened in August, and almost half happened on weekends, mostly on Sundays.

    Why? The researchers write that many of the cases are based on perceptions of masculinity and power being challenged. The reason so many cases happen on weekends and in August, they argue, is that an estranged parent (again, usually the father) will have access to the children during the summer months and weekends--but by the end of that time, he may have to return them to the mother, which would explain the killings happening in August and on Sundays. (The data bears this out: the most common motive behind the killings, the researchers found, was a family breaking up, which included issues like access to children. That category accounted for two-thirds of stated motives.)

    The team also breaks down some assumptions people might make about the killers, such as that they were always frustrated men with a history of mental illness. In fact, 71 percent of the killers were employed, and many were in successful careers. (Although many also weren't; the researchers say the second most common reason given for the murders was a financial strait.)

    The data, the team says, argues for placing killings like this in a new category of crime, different from the "spree killings" they're sometimes lumped together with. The researchers go so far as to categorize family killings into four different sub-categories.

    From a press release on the study:

    Self-righteous: The killer seeks to locate blame for his crimes upon the mother who he holds responsible for the breakdown of the family. This may involve the killer phoning his partner before the murder to explain what he is about to do. For these men, their breadwinner status is central to their idea of the ideal family.
    Disappointed: This killer believes his family has let him down or has acted in ways to undermine or destroy his vision of ideal family life. An example may be disappointment that children are not following the traditional religious or cultural customs of the father.
    Anomic: In these cases the family has become firmly linked in the mind of the killer to the economy. The father sees family as the result of his economic success, allowing him to display his achievements. However, if the father becomes an economic failure, he sees the family as no longer serving this function.
    Paranoid: Those who perceive an external threat to the family. This is often social services or the legal system, which the father fears will side against him and take away the children. Here the murder is motivated by a twisted desire to protect the family.

    It might be wise to take some of that with a grain of salt: there are (thankfully) not that many cases to draw conclusions from. But, as the researchers say, the patterns that do appear warrant more data.

    The study is to be published in the Howard Journal of Criminal Justice.


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    The complete science of barrel-aging whisky is something we have only recently come to understand. In the 1970s we began to uncover the full details of what happens when the Glenfiddich distillery men lay the base spirit to rest in oak casks and store it in one of our 46 warehouses. Our Malt Master, Brian Kinsman, told me that every new cask of spirit has the same opportunity of becoming a 12-year-old Scotch as it does of becoming one of the extremely rare casks that make up our incredible 50 Year Old. While we cannot predict what will happen in each individual cask, we do know that approximately 70% of the flavor characteristics of Glenfiddich come from the wood and the time spent maturing in it. In Scotland, we predominately use two types of wood to mature whisky-American white oak (Quercus alba) and European oak (Quercus robur). American wood is the most popular, accounting for approximately 90% of casks used today, but it is important to remember that each different wood gives its own unique characteristics to the whisky. For example, Q. alba produces vanilla flavors (fruity, sweet) while Q. robur yields a rich, tannic kick. At the Glenfiddich distillery we take the base spirit, which comes off the still at 65.6% ABV, and add it into the casks. The wood casks perform three important functions to the aging of the whisky: ‘subtractive,' ‘additive,' and ‘interactive.' The relationship between the liquid and the wood is one of the many intriguing aspects of whisky. After all, that mysterious and storied past is part of the allure of Scotch whisky!

    by Mitch Bechard, Glenfiddich Ambassador

    To learn more about the fascinating world of single malts, visit

    Glenfiddich® Single Malt Scotch Whisky is a registered trademark of William Grant & Sons Ltd.

    "Every new cask of spirit has the same opportunity of becoming a 12-year-old Scotch as it does of becoming one of the extremely rare casks that make up our incredible 50 Year Old."
    Brian Kinsman
    Glenfiddich Malt Master


    Wood casks remove impurities within the whisky. The inside of American oak barrels is usually charred. Charcoal, with its billions of tiny pores, is a great purifier. It has the ability to remove unwanted components such as sulfur-containing compounds. On the other hand, European wood is only lightly toasted and therefore does not have the same pronounced subtractive qualities.

    Wood gives flavor and character to the whisky. Oak wood contains hemicellulose, lignin and tannins. These elements cultivate chemical reactions with the base spirit, adding aromatic molecules to produce flavors such as coconut, vanilla and fruit. Wood also varies the color of the whisky. We find that Scotch whisky matured in European wood will have a darker, more reddish hue to it than that which has spent most of its life in American wood.

    Wood is semi-porous, meaning that the cask is always breathing and interacting with its warehouse environment. Around 2% of the volume of each cask-water and ethanol-evaporates from the cask each year. We call this "the angels' share." As we age the whisky, the alcohol content of the liquid drops. We must be mindful of this, as spirit below 40% ABV can no longer legally be called Scotch whisky.


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    Quantum Teleportation of Light Waves

    A Schrödinger's cat is a quantum superposition of two light waves. The two light waves are interpreted respectively as a living cat and a dead cat. Their quantum superposition hints to a "quantum" cat paradoxically alive and dead at the same time. The figures shown are numerical functions reconstructed from the measured light amplitudes at the input and output of the experiment.

    © Science/AAAS

    Quantum teleportation, more reliable than ever before, at greater distances than ever before.

    Quantum teleportation has taken another step forward, thanks to two complimentary experiments, one from ETH Zurich and one from the University of Tokyo. The researchers have demonstrated the most reliable yet version of quantum teleportation--what Nature is calling "quantum teleportation on demand."

    A quick explanation of quantum teleportation, from the Nature abstract:

    Generically, teleportation protocolsproceed by three steps (Fig. 1): a pair of quantum systems in an entangled state is produced and distributed, one to a sender (Alice) and the other to a receiver (Bob); Alice makes a joint measurement of her member of the entangled pair and the unknown state she wishes to teleport, and sends the measurement result to Bob; Bob uses the measurement result he receives from Alice to manipulate his quantum system in a predetermined way. After this manipulation, Bob's quantum system ends up being in the unknown state, that teleported from Alice to Bob, with the only direct communication being a classical message - Alice's measurement result.

    Quantum teleportation has some pretty significant implications for communications; it works in a way not that dissimilar from the PGP-secured email we outlined here, except there's literally no physical link between the sender and receiver. (Read more about the implications for communications in Rebecca Boyle's excellent explainer.)

    In the new experiments, conducted at the 100-micrometer scale and at temperatures of around 20 millikelvins, "Alice" and "Bob" from the example above are separated by about 5 mm. The University of Tokyo experiment managed to induce entanglement deterministically, which had only been done before at distances about 1,000 times smaller. And those previous experiments had only managed to do so reliably about 1 percent of the time, compared to this experiment, which teleported a qubit about 40 percent of the time (and reproduced it on the other end with about an 88 percent accuracy). So this is a huge leap forward!

    You can read the two papers here and here. [Eds. note-links don't appear to be live to the public yet. Check back soon.]


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    The Geek Family Tree


    Where Star Wars and Star Trek geeks share common ground.

    Hundreds of years ago, the term geek wasn't as benign as it is today (high fives all around, gang). In 18th-century Austria-Hungary it was synonymous with freak--literally, used as the word for circus performers. Now, at worst, it's used to describe someone who's maybe a little too into comic books or tech.

    Flowtown breaks down the evolution of the word geek over time in this infographic. See the fall of the Ubergeek Steve Urkel and the kaleidoscopic fracturing of the pop culture geek.

    But could some of these things actually be nerdy?


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    A quick glimpse of the Kawahira people

    By Brazilian law, no one but a select few government workers is allowed to trespass on the land of the Kawahira, a tiny community of nomads that lives in the Amazon. They're one of the country's uncontacted peoples, indigenous groups that live in isolation from the rest of the modern world. Which makes this quick video of nine members of the tribe making their way through the jungle a major find. Up until now, the tribe's existence has largely been determined by the discovery of abandoned habitations and tools, according to TreeHugger.

    The footage was shot by an employee of the Brazilian National Foundation of the Indian (FUNAI), the governmental body charged with preserving the lands and rights of the country's indigenous peoples, a significant portion of whom live in isolation. FUNAI employees are allowed into Kawahira territory in order to ensure outsiders aren't sneaking in and jeopardizing the tribe's right to self-determination.

    As of 2007, FUNAI reported 67 uncontacted tribes like the Kawahira in the country, 27 of which were discovered between 2005 and 2007. Brazil, home to 60 percent of the 2.7 million square mile Amazon rainforest, has more uncontacted peoples than any other country in the world.

    There's some very creepy zooming-in on the children of the group, but all in all it's a very cool, very rare look, although it's hard to see much beyond flashes of skin between the trees.



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    Baby Monitor

    Baby's first surveillance system.

    Wikimedia Commons

    Hackable baby monitors reveal the vulnerability of everyday things.

    Baby surveillance devices: adorable and practical when used by parents, freaking creepy when used by strange adults on the internet. A couple in Houston recently discovered this firsthand when a man hacked their baby monitor and used it to shout profanity at their sleeping daughter.

    The more computerized and dependent on wireless communication everyday objects become, the more vulnerable they are to hacking. The late security expert Barnaby Jack exposed weaknesses in Pacemakers, insulin pumps, and ATMs, showing how everyday objects not commonly thought of as targets can be taken over by malicious third parties. Often, the weaknesses in these machines exist, not because they are hard to fix, but because manufacturers don't even consider the possibility of hacking.

    In this case, the solution was basic web security. The monitor used Wi-Fi, and the lack of a password meant accessing the Wi-Fi network gave the hacker a way in to taking over the monitor. Creepy! Fortunately, documented cases of baby monitor hacking are rare. Still, as more and more devices rely on the internet, it's never a bad idea for manufacturers to think about how their products could realistically be hacked, and build in safeguards (like requiring a password during set-up) to protect against that.



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    David O'Carroll, University of Adelaide.

    Dragonflies process light and dark a little differently than the rest of us.

    New research into the visual system of dragonflies could one day improve target detection and tracking in robotics, according to a pair of Australian researchers.

    Steven Wiederman and David O'Carroll from the Center for Neuroscience Research at the University of Adelaide in Australia have been studying insect vision in the hopes of improving artificial vision for robotics and to develop neural prosthetics. They've found that dragonflies have an unusual visual circuit that allows them to see dark moving objects.

    Visual processing in most animals, both vertebrates and invertebrates, consists of two channels that process light and dark separately, called ON and OFF channels.

    "Most animals will use a combination of ON switches with other ON switches in the brain, or OFF and OFF, depending on the circumstances," according to Wiederman, lead author of the study in the Journal of Neuroscience. The dragonfly, in contrast, uses a combination of both ON and OFF switches to see dark objects. It's possible that other animals use this type of circuit as well, and this is just the first time scientists have discovered it.

    It allows dragonflies to respond to dark moving targets, like potential prey, much better than the researchers expected.

    Wiederman and O'Carroll hope to translate their new knowledge of how dragonfly visual circuits work into an autonomous robot that would mimic the insect's vision and movement.


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    Hello, TailBot!

    With the goal of making a robot that can run, jump, and maneuver in the air, a student team at Michigan State University came up with this monkey-like miniature machine: TailBot. It is super goofy. For example: to run, it doesn't run on its legs so much as knock itself over with its tail and crawl by gyrating its back. To jump, it comically bends its legs and blasts over (relatively very high but still like 2-foot-tall) walls.

    But the 1-ounce, 3-inch-tall 'bot can control its landing by moving its tail while in mid-air, and leap several times its own height. Neat tricks, even if TailBot doesn't quite stack up to the greatest jump-'bots out there.

    [MSU via TIME]


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    SEA Hacks WaPo

    via SEA Twitter

    By using a link-referral service called Outbrain, the Syrian Electronic Army dove into the Washington Post.

    Today, the Washington Post (newly owned by Amazon's Jeff Bezos) posted a brief note admitting that certain pages on the Post's website had been hacked by the Syrian Electronic Army. The Syrian Electronic Army, a group of hackers known for infiltrating and hacking western news organizations that have criticized the Syrian government, is not exactly organization to shy from gloating, and tweeted its victory, saying it had also hacked the websites of Time and CNN, "in one strike." They did it by hacking a service called Outbrain that most readers haven't heard of, but that most publishers have. In fact, it's one that we use here on PopSci, though we have not, as yet, been hacked. We've been told by two sources at Outbrain that the hack was carried out by phishing an Outbrain employee via email--a standard Syrian Electronic Army tactic.

    Outbrain is responsible for the "related stories" links you see underneath lots of posts on publications all over the internet. Outbrain is one of many services that help publications make money in a time when lots of publications aren't really making any money. Those related stories links are in two columns: internal and external. The internal links are links to stories by your own publication (or in-network publications; PopSci might include a link to our photography sister site, PopPhoto). The external links are from brands or publications; they're ads, basically. If Nike wants to link PopSci readers to a cool new shoe's site, or a new publication wants to make PopSci readers aware of their site, it can pay Outbrain to stick a link into that external links section. Then, as a reward for allowing those links on our site, Outbrain pays us a portion of that. How large that portion is depends on the individual deals struck with Outbrain, but I can say that PopSci's deal gives us 60 percent of the cash paid by Nike, or whoever, to Outbrain. An Outbrain representative tells me that's a pretty standard split.

    Outbrain is very popular; it's easy and unobtrusive and gives lots of money to publishers. We use it, as do the Guardian, USA Today, the Daily Beast, Slate, CNN, Mashable, and Fast Company, among others. It's not something readers really notice, but Outbrain has complete control over that block of links.

    So if someone could get access to Outbrain, they'd have a nice little backdoor into all sorts of other publications, which is exactly what makes it such a sneaky and clever avenue for the Syrian Electronic Army to take. Diana Fox, the director of business development at Outbrain, told me that the hack was done by phishing, which is a standard Syrian Electronic Army tactic--they try to trick people into entering their usernames and passwords. "It wasn't like they hacked into our back end," she says. "They literally had one person fill out information [like] their email address and got into our stuff that way." Lisa LaCour, on the marketing side of Outbrain, confirmed that this was the method used by the SEA to get access through Outbrain.

    Phishing is a low-rent tactic, but it's astonishingly effective; it's the method the SEA used to hack into SocialFlow, the New York Post, and other companies earlier this week. It also explains how the SEA "compromised emails of Outbrain," as one hacker told eHackingNews today.


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    Mechanical sneezer, 1940

    Popular Science archives

    A bizarre scene from the Popular Science archives

    Let's take a break from trying to wrap our brains around quantum teleportation and robot aliens, and focus on some simpler science: How do sneezes work?

    That's the mystery two researchers are working on in this photo from the April 1940 issue of Popular Science:

    Infectious germs are spouted from the mouth of a mechanical sneezer developed for medical research by William F. Wells of the University of Pennsylvania medical school in Philadelphia. By means of compressed air, the apparatus blows air-borne germs through a tube into a glass bell housing an experimental rabbit, to simulate the common method of transmission of germs by human sneezers and coughers.

    Hey, it only took us 73 more years to invent a barfing machine! Now that's progress.


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    Kepler Space Telescope

    Kepler is designed to look for Earth-like planets orbiting Sun-like stars in a temperate "Goldilocks zone," where temperatures are right for liquid water. It stares at a patch of around 156,000 stars in the constellations Cygnus and Lyra and notes teeny blips in their brightness, which could indicate planets passing in front of the stars' faces.


    But they won't put the hobbling two-wheeled spacecraft out to pasture yet.

    Well, NASA's crippled Kepler space telescope, launched in 2009, is officially beyond repair. Two of the four wheels used to align the telescope have failed over the past year, and NASA engineers haven't been able to get either of them working again. NASA announced today that attempts to fully restore the spacecraft have ceased.

    This may not spell the total end of Kepler's mission, though. NASA will still try to figure out a way to use the spacecraft for whatever scientific research it can manage in its current condition, with one reaction wheel short of a workable set. The agency put out a call for scientific white papers proposing alternate uses for Kepler a few weeks ago.

    Kepler was originally designed to hunt for Earth-sized exoplanets in the galaxy, and during its initial four-year mission, it found more than 100. Its mission was extended in April 2012, and scientists are still sorting through all the data it has sent back in the meantime.


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    Wild Turkey

    Vince pahkala via Wikimedia Commons

    It's not what you have, it's how you use it.

    For male wild turkeys, reproduction is an all-family effort. Less attractive males often don't get to mate, but they're still driven to ensure their genetic material is passed on. So they help their brightly colored, dominant brothers seduce hens in a process called, rather coyly, "cooperative courtship."

    The dominant males are more ornate, with more of the masculine traits that make the lady turkeys swoon: brightly colored heads and longer snoods (the reddish flesh that hangs over a turkey's beak). But if the subordinate turkey brothers are genetically pretty similar, what makes one more attractive than the other? According to a study in this week's PLOS Genetics, it's not the genes that matter, it's how they're expressed.

    Male turkey brothers duke it out for dominance during the winter before they reach sexual maturity. Whoever wins becomes the dominant, mating male, while his brothers play wingmen, helping him find willing mates.

    University College London's Judith Mank and her colleagues found dominant and subordinate males had profound differences in the way their genes were expressed. Compared to their subordinate counterparts, the attractive, dominant males showed higher expression of masculine genes predominantly found in males, and lower expression for genes mostly found in females. So genetically, they have more masculine traits and fewer female traits. Apparently female turkeys like a manly man.

    Though researchers still don't know exactly how some turkeys become dominant and some submissive, they think it could be tied to male hormones affecting gene expression, according to the study's press release.

    Next, Mank will explore whether the same pattern of gene expression holds true for female turkeys.

    The study appears in the August 15 issue of PLOS Genetics.


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    Anarchy Of Things

    Paul Lachine

    Over at Forbes, Andy Greenberg has penned a fascinating profile of Alex Karp, the CEO of the CIA-funded data mining company Palantir. Palantir applies Silicon Valley data-gathering expertise to the tremendous amount of secret data that intelligence agencies and the military generate. Palantir then takes all the data and makes it useful, tagging the information and analyzing patterns to, for example, predict attacks in Iraq or track down cartel members. The company is moving into the private sector, away from just defense contracting, and bringing lessons from the battlefield to banks looking to stop identity theft and cyberattacks.

    The profile covers a lot about the company and its core philosophy. Greenberg focuses on Karp because his personal ethical convictions could stop Palantir from abusing the power of information in its grasp. My favorite moment was a scene describing Karp's office. What kind of room does a man who mines through secrets keep?

    His office, decorated with cardboard effigies of himself built by Palantir staff and a Lego fortress on a coffee table, overlooks Palo Alto's Alma Street through two-way mirrors. Each pane is fitted with a wired device resembling a white hockey puck. The gadgets, known as acoustic transducers, imperceptibly vibrate the glass with white noise to prevent eavesdropping techniques, such as bouncing lasers off windows to listen to conversations inside.

    The full profile, over at Forbes, is well worth a read.


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    I Get The Joke But Read This Post Please

    via SnorgTees

    It's even worse for avoiding herpes.

    Today in scientific studies that confirm the obvious, we have a paper from the Duke University Medical Center that led to this stellar Reuters headline: "'Pull-out method' tied to unintended pregnancies." Well, um, yeah.

    Most current guides on contraception cite this Guttmacher study for its results on the pull-out method, also called coitus interruptus. That study was performed back in 2009, and found that with perfect use, the pull-out method had a failure rate of about four times out of 100. Not bad, really! But, of course, the whole problem with the pull-out method is that it's sort of hard to perform it perfectly every single time. By averaging that failure rate with the rate of pregnancy when it was used incorrectly all the time, the researchers landed on a failure rate of about 18 percent as a best guess for average use of the method. That's only slightly worse than the average failure rate of condoms (17 percent), though it's pretty easy to argue that condoms are easier to use than the pull-out method.

    The new study, performed by, swear to god, Dr. Annie Dude, found that 31 percent of women surveyed had used the pull-out method in the past two years. Twenty-one percent of those women reported an unintended pregnancy--significantly more than the unintended pregnancy rate of women who used non-pull-out-method forms of birth control (13 percent). "We found that people tend to use the withdrawal method when they're not really planning ahead," said Dr. Dude, confirming what we all pretty much knew anyway.

    The biggest issue with the results of the study is that it suggests more women than previously thought are using the pull-out method, which, aside from being a not-very-effective means of contraception also provides precisely zero protection from sexually transmitted diseases. So, final judgment? The pull-out method: not one of the better methods.

    [via Reuters]


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    Slit of the Tongue

    For some people, a sliced tongue can be fatal.

    Erik Isakson/Getty Images

    A person with normal clotting ability would have to lose nearly 40 percent of his blood immediately to die of blood loss. The arteries with this bloodletting potential, though, such as the radial artery in the arm and femoral artery in the leg, are buried under too much flesh to be nicked by even the heaviest manila cardstock. "It would be tough to kill yourself on a paper cut," says Beau Mitchell, a bleeding-disorder specialist at the New York Blood Center, an organization that supplies blood to hospitals.

    A stationery slice could turn deadly, however, for the 12,600 people in the U.S. with severe hemophilia and the 200 Americans with a disorder called Glanzmann's thrombasthenia. If one of these people sliced an exposed blood vessel, like the one under the tongue, their blood would not be able to clot to plug the wound. Glanzmann's patients are especially vulnerable, Mitchell says, and could lose 25 percent of their blood within eight hours from such a cut. Without medical treatment, their bodies couldn't produce enough new blood cells to replenish those lost, and they would die within a few days.

    Although people with these diseases should probably avoid licking envelope seals, we should all avoid ninjas armed with paper daggers. According to Ronald Duncan, a master of the martial art ninjitsu, anyone can fold a piece of paper, origami-style, to fashion a sharp knife. Duncan trains police officers and the military to look out for these weapons because a jab to the carotid artery in the neck could be fatal. "A few other parts of the body can bleed out in 35 seconds if someone is really adept," he says. "But we try not to make this information available to too many people."

    This article originally appeared in the December 2009 issue of Popular Science magazine.


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    Space Toilet

    via @Cmdr_Hadfield

    Imagine peeing in this.

    In space, no one can hear you poop. Or at least, probably not, since you're trying really hard not to poop at all. Because this is what you have to go in.

    Earlier today former ISS commander Chris Hadfield shared this terrifying picture of what the humble commode looks like on Russia's Soyuz spacecraft via his Facebook page. And, yikes. On the left is what he describes as the "human interface" aspect.

    He also shared this fascinating, terrible tidbit of astronaut lore: Before being catapulted into the last frontier, Soyuz astronauts get not one, but TWO enemas. And we thought not doing laundry for months sounded bad.


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    Water Ski On A Flying Saucer

    The hardest part isn't making the flying saucer, it's staying on!

    Popular Science Magazine, August 1969

    Including a backyard trampoline, a playhouse built from window blinds, a flying saucer that doubles as a water ski, and more

    Summer is almost over SIGH. If you're eager to squeeze in some last-minute leisure, check out these retro do-it-yourself projects, culled from the Popular Science archives. They include a backyard trampoline, a playhouse built from window blinds, a flying saucer that doubles as a water ski, and more. Here's to a rockin' (if brief!) old-school summer.

    See the gallery.


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