OVER THE TOP, Sylvester Stallone, 1987.

Could a Human Beat a T. Rex In Arm Wrestling?

“First, we’re assuming that the T. rex won’t just eat the person, right?” asks Jack Conrad, a vertebrate paleontologist at the American Museum of Natural History in New York. Right. This is a sanctioned match, and killing your opponent is strictly against the rules. Who’s coming out on top? “Doesn’t matter,” Conrad says. “There’s no chance that any human alive could win.” The T. rex’s arms might have looked wimpy, but they were extremely strong. Each was about three feet long and, based on the size of the arm bones and analysis of the spots where muscle attached to the bone, they were jacked. “The bicep alone—and this is a conservative estimate—could curl 430 pounds,” Conrad says. Even the beefiest humans max out at around an embarrassing 260 pounds. Surely an Over the Top–era Sylvester Stallone would put up a good fight? “Not even Lou Ferrigno in his prime would stand a chance,” Conrad says. “They didn’t just have big biceps. Their chest and shoulder muscles were huge too. They had huge arms and shoulders—bigger than my leg. They had the strength to rip a human’s arm right out of its socket.” There is a chance, however, that your competition might not be able to put all that beefy muscle to use. There are dozens of hypotheses about what the T. rex used its arms for, Conrad explains, but the ones taken most seriously involve pushing itself up if it was lying on its belly, tossing big chunks of meat into its mouth, or holding onto females during what scientists suspect was a very vigorous mating routine. These ideas are favored because such actions required Barbie doll–like up-and-down motions of the arm, and fossil evidence indicates that the dino king was incapable of rotating or twisting its arms. “The T. rex probably couldn’t have done the arm-wrestling move,” Conrad says. “So maybe you could get him on a technicality.” Think you can stump us? Send your questions to fyi@popsci.com.

Why Don’t Loud Snorers Wake Themselves Up?

A husband’s snoring might keep his wife awake, but there are a couple of reasons he’ll sleep through his own rumblings. Our ability to sleep through loud noises changes during the night as our body transitions between the different stages of the sleep cycle, explains Neil Kline of the American Sleep Association. Even snores louder than 100 decibels—which exceeds the volume of a fire alarm—may fail to wake snorers from deep “slow-wave” sleep. But during the roughly 80 percent of the night that people are not in deep sleep, their snores can wake them up dozens of times; they just don’t realize it. A big snort will typically wake a person for only a few seconds, not long enough to fully awaken or to remember it the next morning, says Clete Kushida, the president of the American Academy of Sleep Medicine. As a result, snorers remain oblivious of their interrupted sleep. And if the wife was lucky enough to doze off at the same time as the snorer did, she’s probably oblivious to the interruptions as well. But ignorance isn’t bliss: This type of fragmented sleep can significantly increase sleepiness during the day. Have a burning science question you’d love to see answered in our FYI section? Email fyi@popsci.com

Ask a Mars Career Counselor: What Would be the Best Job to Have in a Mars Colony?

You’ve just landed on the Red Planet and are looking for a fresh start. Sure, that job selling respirators at the local space-hardware store sounds cozy, but it’s a dead-end career. Mars will be ripe with opportunity; you just have to figure out how to tap it. So here’s the secret: Go into construction. You’ll learn useful skills and be out on the surface, where the real action is. Explore the landscape on coffee breaks. All you need to do is stumble upon a nice deposit of precious material—like platinum or deuterium, a hydrogen isotope that could fuel fusion reactors—and you’ll have it made. Next, buddy up with the engineers working to terraform the Martian hillsides. It’s their job to turn all that red dust into Earth-like soil that can support robust vegetation and seed the atmosphere to rain and form lakes and oceans. Figure out where future beachfront property will be, buy it, and auction off lots to the highest bidder. Of course, this prosperous career path has its risks. You’ll be outdoors a lot, and Mars’s atmosphere is pretty thin, so cosmic radiation could fry your DNA. Things could fall on you on construction sites. And you’d probably go prospecting alone (why split the profits?), so no one could help you if you got lost or fell into a crater. You could play it safe in the colony, working at the Spacemart. But you’re on Mars—take a chance! Robert Zubrin is president of the Mars Society and author of How to Live on Mars._ Science questions keeping you up at night? Send them to fyi@popsci.com.

How Do I Become an Internet Rock Star on the Cheap?

Chances are you’ve got a more advanced recording studio in your laptop than the Beatles had when they made Sgt. Pepper’s, so record your music yourself. Then build an Internet home that can grow with your entourage. Skip the cookie-cutter MySpace stuff and get a full-fledged content-management system like WordPress or Drupal, which will allow you to build your empire as you go: a blog, forums, photos, videos — all in one place that you control. And make sure it can support a digital music store so you can sell your own MP3s. I use PayPal Micropayments because the commission structure is better for small purchases than with iTunes or Amazon. If you don’t know HTML or PHP, find a sucker. . . er, a fan to build it for you. Create merchandise on demand with CafePress, Spreadshirt or Zazzle to avoid buying boxes of T-shirts that’ll sit in your basement. There are still people who buy CDs, and for $4 each, CD Baby will store, sell, and ship your discs. It will also push your music to digital outlets like iTunes and Amazon MP3. When you’re ready to play live, use eventful.com, which lets people request a show in their town. Why slog from city to city in an old van unless you know you’re going to sell some tickets? Promote yourself on Twitter, broadcast live shows on Ustream, use Creative Commons licensing to encourage folks to make new content, like music videos, with your music. Send out a million pieces of yourself to interact with potential fans. If they’re out there, they’ll find you — and hopefully sometime after that, give you money. Above all else, keep it simple and honest. Leave the 24-piece orchestra out of it (unless you’re a 24-piece orchestra). Extra credit: Hire a camera crew to film one of your shows and release it as a combination DVD/live CD called “Best. Concert. Ever.” on February 10 for only $20. Actually, hold off on this one. I’ll let you know if it works for me. PopSci contributing troubadour Jonathan Coulton quit his programming job in 2005 to become a full-time musician. Find him at jonathancoulton.com. Send your science and technology questions to fyi@popsci.com.

Can People Safely Eat Cat Food?

Let’s take a look at the ingredients in a typical can of cat food: meat by-products, chicken by-product meal, turkey by-product meal, ash, taurine. Nothing too horrible, but in general, these things don’t constitute a healthy human diet, says Dawn Jackson Blatner, a registered dietitian with the American Dietetic Association. “That said, I’m fully confident that your body can handle kitty chow.” Your liver, kidneys and skin do a terrific job of removing foreign substances from the body, especially mild ones like those found in cat food. “Technically, you could safely digest a baseball,” Blatner says. Perhaps the worst stuff in cat food is the high mineral content in the ash, but your body would clear that out quickly. Actually, the ingredients listed on the organic blends of cat food sound pretty tasty. Newman’s Own canned beef formula uses only free-range beef from Uruguay, is 95 percent USDA-certified organic, and is chock-full of vitamins. Pass me a spoon, right? “Those are better,” Blatner says, “but they too are developed with cat nutrition in mind and aren’t formulated to keep humans healthy. It’s OK to satisfy the occasional craving, but you shouldn’t make it a staple of your regular diet. It’s cat food for a reason.” Did you place a bet on a science question? We’ll help you settle up. Send your questions to fyi@popsci.com.

Is There Really No Way to Keep a Goose Out of a Jet Engine?

Popular Science took a gander at a sticky issue, in the wake of the plane downed in the Hudson River last January: Unfortunately, there’s pretty much no way to protect jet engines from geese or other large birds. In fact, fastening some sort of shield over a jet engine could actually make things worse. From 1997 to 2007, reported animal strikes per civil flight more than doubled, reaching 7,600 in 2007a€”mainly glancing shotsa€”in 54 million flights, according to Richard Dolbeer, former chairman of the volunteer organization Bird Strike Committee USA. Because most bird strikes occur less than 500 feet off the ground, experts blame the growing populations of Canada geese and other birds near airports. Foie Gras Alert When a goose or another bird is sucked into a plane’s engine, the resulting carnage can jam up the turbine enough to stop the engine. Most famously, a flock of geese shut down both engines of a 150-passenger Airbus A320 shortly after takeoff this January, forcing the pilot to make an emergency landing in New York’s Hudson River. Although one might assume that airlines could shield jet engines with a screen or a set of bars, it’s simply not practical, says Russell DeFusco, vice president of bird-strike consultants BASH, Inc. A 12-pound goose hits a plane traveling 150 mph on takeoff with roughly the same force as dropping a grand piano from the second story of a building, says Matthew Perra, a spokesman for engine manufacturer Pratt & Whitney. Beyond the fact that any screen would create turbulence and inhibit free-flowing air from entering the engine, thus weakening its thrust, if the screen broke on impact, it too could be sucked into the engine and cause even more damage, DeFusco says. Per FAA regulations, before a new engine model can be strapped to planes it must first prove that it can safely shut down after ingesting a four-pound bird carcass. This test might not be rigorous enough, however, considering that the largest Canada geese tip the scales at 14 pounds. Bird-repelling techniques now in use at airports include draining fowl-friendly ponds and scaring off birds with firecrackers. The FAA is also working on a bird-detecting radar like the one Kennedy Space Center has had since a space shuttle’s 2005 run-in with a vulture. Got a burning science question? Send your questions to the pros at fyi@popsci.com.

How Long Would it Take Piranhas to Eat a Person?

After a trip to the Amazon jungle, President Teddy Roosevelt famously reported seeing a pack of piranhas devour a cow in a few minutes. It must have been a very large school of fish—-or a very small cow. According to Ray Owczarzak, assistant curator of fishes at the National Aquarium in Baltimore, it would probably take 300 to 500 piranhas five minutes to strip the flesh off a 180-pound human. But would this attack even happen? Piranhas get a bad rap. Yes, they are carnivorous critters with sharp teeth. “It’s like they have a mouthful of scalpels,” says Erica Clayton, Amazon collection manager at the Shedd Aquarium in Chicago. Even so, instances of piranhas biting humans are extremely rare. Most are happy snacking on other fish and plants. In general, if you leave them alone, they’ll do the same for you. Still, if you decide you must take a dip in the Amazon, make sure you don’t have any open wounds—-the smell of blood attracts piranhas. Need an answer to a pressing science question? Send it our way. Send your questions to fyi@popsci.com.

Why Does Organic Milk Have a Longer Shelf Life Than The Regular Kind?

It all has to do with where the cow was milked. “Organic milk often has to travel thousands of miles to reach distribution points,” says Dean Sommer, a cheese and food technologist at the Wisconsin Center for Dairy Research at the University of Wisconsin. To survive the journey and leave time to spare in the fridge, farmers pasteurize organic milk at higher temperatures than conventional milk. Nearly all milk is pasteurized, or heat-treated, to kill off disease-causing microbes. Heating organic milk upward of 200°F instead of the typical 161° destroys more of the organisms responsible for spoiling milk. With those bugs knocked out, organic milk lasts 25 to 40 days longer than the ordinary stuff. But there’s a catch. The extra heating is expensive and can give the milk “a cooked or scorched flavor,” Sommer says. And be sure to drink up once you crack the carton. Exposed to air, organic milk goes bad just as quickly as any other milk. PopSci has all of the most delicious answers. Submit your science and technology questions to fyi@popsci.com.

Could There Be a Planet Hidden on the Opposite Side of our Sun?

PopSci asked the scientist who has peered around it. Here’s what we found out: The sun might seem like a pretty huge galactic blind spot, but we’ve already managed to glimpse behind it, and there’s nothing there in the way of another Earth, says NASA scientist Michael Kaiser, “unless it’s awfully tiny.” Kaiser is the project scientist for NASA’s Solar Terrestrial Relations Observatory (STEREO) mission, which in 2006 sent two golf-cart-size satellites into orbit around the sun to study the explosions on the solar surface that are a major factor in space weather. A few months after their launch, the two probes were angled such that they could see beyond the sun, but they found no planets lurking behind the big star. Even if we couldn’t see behind the sun, the gravitational pull of a roughly 100-mile-wide planet hiding there would noticeably affect the orbits of the other planets. And if astronomers had somehow missed that detail, Kaiser says, an unaccounted-for tug of gravity in the solar system would have disrupted the orbit of man-made satellites circling the Earth or interfered with intra-solar-system spacecraft. That hasn’t happened, so unless beings on a hidden planet have invented both an invisibility cloak and a gravity-masking device, the other side of the sun is almost certainly just empty space. You’ve got questions. We’ve got answers. Send your science questions to fyi@popsci.com.

What’s the Chance That Falling Space Debris Will Hit Me?

So what if your friends call you paranoid? It happened in 1997! But, there’s no need to don a hard hat just yet. The odds that one of the millions of pieces of trash orbiting Earth will fall and hit you are about one in a trillion, says Bill Ailor, director of the Center for Orbital and Reentry Debris Studies. The risk that someone will get hit can run far higher, though, says Nicholas Johnson, NASA’s chief scientist for orbital debris. NASA and other space agencies aim to keep the risk of injury from falling objects lower than one in 10,000. The risks typically run higher with large objects. For example, there’s a one-in-1,000 shot that the Hubble Space Telescope could hit someone if it falls from orbit once it’s decommissioned, so NASA will preemptively steer it into the ocean. There’s only one recorded instance of debris hitting a person. In 1997 Lottie Williams was exercising in a park in Tulsa, Oklahoma, when a DVD-size piece of metal mesh from a spent Delta II rocket hit her shoulder. It fell at what NASA classifies as “a very low speed,” and she walked away unscathed. We won’t think you’re paranoid. Go ahead… send your questions to fyi@popsci.com.

Is It True That Birds Can’t Fart?

It’s not that they can’t. They just don’t need to, says Mike Murray, a veterinarian at the Monterey Bay Aquarium in California. Birds have the anatomical and physical ability to pass gas, he explains, “but if I saw gas in a bird’s gastrointestinal tract on an x-ray, I’d suspect that something abnormal was going on in there.” Birds don’t typically carry the same kinds of gas-forming bacteria in their gut as humans and other mammals to help digest food, so there’s nothing to let loose. Parrots sometimes emit fart-like sounds, but it’s not what you might think.”They like to make playful sounds like they’re giving you a raspberry, but it’s coming from the north end, not the south,” Murray says. Scientists are a little less certain about whether birds can release gassy buildup from the mouth, though. There’s no official documentation of a bird burp (it’s not a common field of research), but most ornithologists suspect that if a bird needed to burp, it would have no trouble doing so.”Birds are able to excrete lots of things through their mouth,” says Todd Katzner, the director of conservation and field research at the National Aviary in Pittsburgh.”The fact that birds can regurgitate food for their young suggests that they can also reverse the direction of other things down there. I’d be pretty surprised if birds didn’t burp.” Submit your science and technology questions to fyi@popsci.com.

Crocodile-like Reptiles Lived in the Arctic 55 Million Years Ago. Could it Happen Again?

Yes, but probably not anytime soon. The Intergovernmental Panel on Climate Change estimates that the planet’s average air temperature could warm by as much as 11.5°F by the end of the century. As a result, the world could be warmer than it was 55 million years ago, says Mark Lynas, author of Six Degrees, an analysis of hundreds of climate studies that reads like a nonfiction version of The Day after Tomorrow. Back then, the Canadian Arctic was as balmy as Florida and lousy with crocodile-like animals called champsosaurs. Determining how individual species, much less entire ecosystems, will respond to rapid climate change is difficult at best, however. In the same regions where scientists found remains of champsosaurs, they also found fossils of their favorite food: turtles. Modern-day crocodiles could certainly be comfortable in a warmer north, but only if the prey and ecosystems required to support them proliferate there too. The Arctic air may warm up, but there will most likely still be plenty of ice in the winters. Even aggressive climate models estimate that it will probably take thousands of years for the ice sheets to disappear year-round, so cold-blooded crocs will have to wait at least that long to head to the poles. Think you can stump us? Send your science questions to fyi@popsci.com.

My Boss Told Me to Shut Off My Computer at Lunch…

…But will the juice required to power down and reboot offset the energy savings? You’ll save some energy turning your computer off for an hour, but those modest energy gains might come at the expense of your computer’s longevity. To figure out just how much energy an average computer consumes during its various states of use, we asked Harvard University physicist Wolfgang Rueckner to run a few tests on his 2005 iMac G5. While starting up and shutting down, the machine gobbled about 130 watts (a measure of the amount of electricity used at any instant). It consumed 92 watts sitting idle, and whispered along at 4 watts in sleep mode. Turned off, it sipped 2.8 watts because it was still plugged into an outlet. Adding in the consumption spikes that occur while shutting down and starting back up, the electricity the computer uses while turned off for an hour is barely less than what it consumes while sleeping. Given these numbers (assume it’s even higher for a computer running Windows, which requires more processing power than a Mac operating system), if 20 people in your office turned off their computers for lunch, you’d collectively save 24 watts during the hour—about what it takes to light a standard compact-fluorescent bulb. At the U.S. Department of Energy’s projected average commercial-energy price of 10.4 cents per kilowatt-hour this year, you’d collectively save — drum roll, please — one quarter of a cent a day. But you’d lose that scant savings over time, Rueckner says, because your hard drive would wear out more quickly from all the spinning it would do while booting up or down. It would take a lot of quarter-cents to justify the $100-plus cost of a replacement drive. Increasingly efficient computers with improved power-management settings will narrow the off/sleep gap. For example, Dell claims that its new Studio Hybrid system uses 70 percent less power than typical desktops. Bruce Nordman, a researcher at Lawrence Berkeley National Laboratory, says that even though turning a computer off will never actually waste power, he notes that” ‘off’ is a very 20th-century idea. We’re always happy to help you prove your boss wrong. Send your questions to fyi@popsci.com.

Why Does My Voice Sound Different When I Hear it On a Recording?

It sounds different because it is different. “When you speak, the vocal folds in your throat vibrate, which causes your skin, skull and oral cavities to also vibrate, and we perceive this as sound,” explains Ben Hornsby, a professor of audiology at Vanderbilt University. The vibrations mix with the sound waves traveling from your mouth to your eardrum, giving your voice a quality — generally a deeper, more dignified sound — that no one else hears. Through a loudspeaker or recording device, you pick up sound only through air conduction. “The sound we’re used to hearing has a lower frequency from the bone vibrations,” Hornsby says. “We like that because it sounds rich and full.” Many people cringe at the playback sound because our brain struggles to accept that this foreign voice is our own. Try to stump us. Send your questions to [fyi@popsci.com](mailto:fyi@popsci.com?subject=stump us).

If a Mosquito Bites Me after I’ve Had a Beer, Can It Get Drunk?

Shockingly, no major studies have been conducted on this topic. “The implications are, however, profound,” says Michael Raupp, an entomologist at the University of Maryland. “Reckless flying, passing out in frosty beer mugs, hitting on crane flies instead of mosquito babes. Frightening!” Fortunately, enough related research exists to make an educated guess. First, does alcohol affect a mosquito’s simple nervous system the way it does creatures with complex brains, such as dogs or Mickey Rourke? In labs, honeybees fly upside-down after alcohol exposure, and inebriated fruit flies have trouble staying upright and fare poorly on learning tests. This suggests that mosquitoes can get tipsy. Now, how much alcohol does it take to get them schnockered? Scientists routinely puff ethanol vapors at insects and measure their sensitivity with devices called inebriometers. Bugs are no lightweights, often withstanding vapor concentrations of 60 percent alcohol, far more than what’s in our blood after a couple beers. “Someone who’s had 10 drinks might have a blood alcohol content of 0.2 percent,” says entomologist Coby Schal of North Carolina State University. To a mosquito, a blood meal that contains 0.2 percent alcohol is like drinking a beer diluted 25-fold. Skeeters might have developed this Ruthian ability to hold their liquor through diet. They also feed on fermenting fruit and plants, which contain at least 1 percent alcohol and might have boosted their tolerance. And in a mosquito, alcohol (and any fluid other than blood) is diverted to a “holding pouch,” where enzymes break it down before it hits the nervous system. Before you try to drink a mosquito under the table, heed this warning from Michael Reiskind, an entomologist at Oklahoma State University: The blood alcohol levels required to do so would almost certainly kill you as well. Science questions driving you mad? Send ’em to fyi@popsci.com.

Why Does Coke From a Glass Bottle Taste Different?

It doesn’t. That’s what Coca-Cola’s spokespeople say, anyway. “The great taste of Coca-Cola is the same regardless of the package it comes in,” they insist. Rather, they say, “the particular way that people choose to enjoy their Coke can affect their perception of taste.” Sure, most people would agree that the cola is indeed delicious and refreshing, and pouring it into a glass or serving it over ice could influence the sensation of its flavor. But is it possible that the subtle variation in taste that some notice among aluminum cans, plastic bottles and glass bottles is more than just a psychological effect of their soda-consumption rituals? Given that the formula is always the same, yes, according to Sara Risch, a food chemist and member of the Institute of Food Technologists. “While packaging and food companies work to prevent any interactions, they can occur,” she says. For example, the polymer that lines aluminum cans might absorb small amounts of soluble flavor from the soda. Conversely, acetaldehyde in plastic bottles might migrate into the soda. The FDA regulates this kind of potential chemical contact, but even minute, allowable amounts could alter flavor. Your best bet for getting Coke’s pure, unaltered taste is to drink it from a glass bottle, the most inert material it’s served in. Even that’s not a sure bet, though. Coca-Cola maintains strict uniformity in processes in all of its worldwide bottling facilities, but it concedes that exposure to light and how long the product sits on store shelves may affect the taste. So yeah, the packaging might mess with Coke’s flavor, but we’ll still take it any day over New Coke. Send your science questions to fyi@popsci.com.

Do Other Animals Have Trouble With Wisdom Teeth?

The third molars—the last of a group of teeth that grinds food into easy-to-swallow chunks—tend to be overcrowded in adult human mouths, and thus require yanking. But every other toothed mammal has room for their “wisdom teeth,” and so did Neanderthals and other early hominids, says evolutionary biologist Leslea Hlusko of the University of California, Berkeley. So why have those teeth become such a pain for us? Genetics play a role in the shape and size of your jaw, but how it develops also depends on how much chewing stress you put on it during your childhood years, Hlusko says. Because we cook our food rather than tear meat from the carcass, it’s generally softer and easier to chew. As a result, over the generations our jaws have shrunk compared with those of our pre-agriculture ancestors, and so we can’t comfortably accommodate three sets of molars. There is some evidence that eating platefuls of raw carrots and other tubers as a kid might help your jaw grow large enough to hold wisdom teeth, but you’re probably as well off crossing your fingers and hoping that you fall into the 15 percent of the population that never develops a set of third molars (and not one of the unlucky few who grow more than four). Of course, then you don’t have an excuse to eat ice cream for a week. Have a burning science question for FYI? Sent it to the editors at fyilive@popsci.com!

Is There a Scientific Way to Measure How Bad a Fart Smells?

You’re in luck. For their senior project, two Cornell University computer-engineering whizzes recently built a machine that does just that. After learning in class how breathalyzers work, Robert Clain and Miguel Salas assembled a fart detector from a sensitive hydrogen sulfide monitor, a thermometer and a microphone and wrote the software that would rate the emission. A “slight perturbance in the air” near the detector sets it to work measuring the three pillars of fart quality: stench, temperature and sound. Temperature, Clain explains, is critical. The hotter a fart, the faster it spreads. “It beeps faster if it’s a high ranker, and a voice rates it on a scale of zero to nine,” he says. “If it ranks a nine, a fan comes on to blow it away. It even records the noise so you can play it back later.” After a few months of construction, they began field tests. “Well, the sample data wasn’t the entire school, but we definitely tested it,” Salas says. The contraption could even have use outside of fraternity houses, Clain says, as a biosensor for harmful hydrogen-sulfide-producing bacteria in hospitals. Or dentists could use it to measure oral malodor. They’ve also received some interest from doctors with four-legged patients. “You can test the health of livestock through the quality of their farts,” Salas says. “Smell and sound can tell you a lot about their bowel movements.” When it came time to present the invention in class, though, Clain and Salas had to test their detector by making raspberry sounds and breathing on it—human exhalations contain enough hydrogen sulfide to trigger the sensor. “It’s hard to fart something really smelly on command,” Clain laments. “Besides, it provided a nicer atmosphere for those around us.” Still, their professor saw fit to award the project a well-deserved A. Have a burning science question you’d like to see answered in our FYI section? Email it to fyi@popsci.com.

Are Men Or Women More Likely To Be Hit By Lightning?

The numbers tell the story: Of the 648 people killed by lightning in the U.S. from 1995 to 2008, 82 percent were male. And as much as we were hoping to uncover a biological cause—extra iron in the male cranium, perhaps, or the conductive properties of testosterone—it turns out men are… just kind of stupid. “Men take more risks in lightning storms,” says John Jensenius, a lightning safety expert with the National Weather Service. Men are less willing to give up what they’re doing just because of a little inclement weather, Jensenius says, and will continue to engage in pastimes that make them vulnerable, such as fishing, camping and golfing. Recreational or sports-related activities are involved in almost half of all lightning-related deaths. Peter Todd, a behavioral psychologist at Indiana University, suspects the difference between the sexes boils down to the basic risk-versus-reward systems that have been part of our biological wiring for thousands of years. For women, Todd explains, the priorities are to protect one’s reproductive role and to care for offspring, which outweighs any inclination to attract potential mates by exhibiting bold behavior. But for men, Todd says, the risk of getting struck by lightning could be outweighed by the reward of proving to other men—and potential female mates—that they’re not afraid of getting struck by lightning. This is particularly true for young men, who have the most to gain by impressing others, thereby raising their status as attractive, daring, healthy mates in the dating pool. And then, zap! Let us put your mind at ease. Send your science questions to fyi@popsci.com.

What Does a Star Sound Like?

Observing a star up close (putting aside for a moment how you’d get there or withstand its heat) is probably like sitting beside an enormous silent fire. Sounds—which are simply pressure variations in a medium such as air or water—can’t propagate in the vacuum of space, so the roiling surface of a A supernova, however, just might be the most brutal concert in the universe. When a star explodes, the massive detonation expels stellar material far into space, and that matter could theoretically provide a medium through which sound vibrations might travel. Assuming you survived the blast—the initial shock wave would travel up to 20,000 miles per second and carry 1044 joules of energy—it would sound like “10 octillion two-megaton thermonuclear devices detonated simultaneously,” says Charles Liu, an astrophysicist at the City University of New York College of Staten Island. “When those guts hit your eardrums, you’ll hear it. That is, as long as your eardrums stay attached.” Send your science questions to fyi@popsci.com.

What Would Happen if I Ate a Teaspoonful of White Dwarf Star?

“Everything about it would be bad,” says Mark Hammergren, an astronomer at Adler Planetarium in Chicago, beginning with your attempt to scoop it up. Despite the fact that white dwarfs are fairly common throughout the universe, the nearest is 8.6 light-years away. Let’s assume, though, that you’ve spent 8.6 years in your light-speed car and that the radiation and heat emanating from the star didn’t kill you on your approach. White dwarfs are extremely dense stars, and their surface gravity is about 100,000 times as strong as Earth’s. “You’d have to get your sample—which would be very hard to carve out—without falling onto the star and getting flattened into a plasma,” Hammergren says. “And even then, the high pressure would cause the hydrogen atoms in your body to fuse into helium.” (This type of reaction, by the way, is what triggers a hydrogen bomb.) Then you’d have to worry about confinement. Freeing the sample from its superdense, high-pressure home and bringing it to Earth’s relatively low-pressure environment would cause it to expand explosively without proper containment. But if it didn’t blow up in your face—or vaporize your face, since the stuff’s temperature ranges between 10,000˚ and 100,000˚F—and you somehow got it to your kitchen table, you’d be hard-pressed to feed yourself: A single teaspoon would weigh in excess of five tons. “You’d pop it into your mouth and it would fall unimpeded through your body, carve a channel through your gut, come out through your nether regions, and burrow a hole toward the center of the Earth,” Hammergren says. “The good news is that it’s not quite dense enough to have a strong enough gravitational field to rip you apart from the inside out.” It probably wouldn’t be worth the trouble anyway, Hammergren laments. White dwarfs are mostly helium or carbon, so your teaspoonful would taste like a whiff of flavorless helium gas or a lick of coal. But if you’re desperate for a taste of star, you don’t really need to travel 8.6 light-years—your fridge is full of the stuff. Most of the elements that make up our bodies and everything around us were formed in the cores of stars and then belched out into the universe over billions of years. Basically everything you eat was once part of a star. Might we recommend some star fruit? Think you can stump us? Send your questions to fyi@popsci.com.

Can a Paper Cut Be Deadly?

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.” Have a burning science question you’d love to see answered in our FYI section? Email fyi@popsci.com

Would a Helium-Filled Balloon Float on the Moon?

A helium balloon on the moon might as well be made of lead. For any balloon to stay aloft in any atmosphere, the gas inside it must be lighter than the surrounding air. Ultralight helium has no trouble climbing in Earth’s atmosphere, which consists mostly of heavy molecular nitrogen and oxygen. “But on the moon, there is no air, so there’s nothing for the helium to rise above,” says Marc Rayman, an engineer at NASA’s Jet Propulsion Laboratory. Unable to escape even lunar gravity, which is one sixth that of Earth’s, the balloon would plunge to the ground. Try throwing a birthday party on the International Space Station, and you’ll run into the opposite conditions. Because atmospheric pressure in the station is kept the same as at sea level on Earth, a helium balloon would have the support it needs to float, but with almost no gravity on the station, there is no force to push up or down on the balloon. “It would just hang there, the same as if you let a hammer go,” Rayman says. We can answer even the toughest science questions. Send yours to fyi@popsci.com.

Just How Old is Dirt?

“It depends on what you mean by dirt,” says Milan Pavich, a research geologist with the U.S. Geological Survey. “The oldest sedimentary rocks are about 3.9 billion years old—they’re in Greenland—and at one time, they were dirt. That’s pretty close to the time the Earth formed.” But those rocks are just proof that dirt existed on the planet way back then. The stuff in your backyard is much fresher. “Most of the dirt you see today is from the past two million years,” Pavich says. About two million years ago, the planet underwent two major changes that drove the formation of new dirt. Global cooling and drying enlarged the deserts, and dust storms redistributed that dirt around the globe. Meanwhile, glaciers began extending from near the poles, grinding rocks, soil, plants and anything else into dirt as they moved over the land. Dirt is still being produced all the time, albeit in much lesser quantities. Beneath the soil’s surface, rocks constantly react with rainwater or groundwater and slowly grind together to break down into smaller minerals. So in that respect, dirt really isn’t that old. Then again, Pavich notes, a lot of what came out of the big bang was essentially dust, which then condensed to form the stars and, later on, planets. “If you think about it,” he says, “dirt and its origin are older than the stars.” You’ve got questions, and we’ve got answers. Send your science questions to fyi@popsci.com.

Can Microwave Technology be Used to Make Food Cold?

Microwaves can transform a frozen pizza into hot, melted goodness in four minutes flat, but they can’t rescue your melted ice-cream sundae. To cook food, a microwave oven converts voltage into high-frequency electromagnetic microwaves. The molecules in food—especially water and fat—absorb this energy and wiggle at high speeds, causing them to heat rapidly and warm the surrounding food. Although quickly turning leftovers cold would be handy, this is a one-way operation, explains David Pozar, a professor and microwave expert at the University of Massachusetts. Microwaves can only speed up atoms, not slow them down. Scientists do have a high-tech method for slowing atoms, however: lasers. Shoot a moving atom with a laser, and it will absorb the laser’s photons and re-emit them every which way, causing the atom to hold nearly still. Placing an atom at the junction of multiple beams can slow its momentum in all directions, decreasing its energy and cooling it. This drops an atom’s temperature a couple hundred degrees Fahrenheit—much colder than anything you’d want to put in your mouth—in less than a second. But because it works most efficiently on low-density gases of atoms of a single element, physicist Mark Raizen of the University of Texas doesn’t think it will be useful for cooling food anytime soon: “Not unless you can subsist on a thousand sodium atoms.” _ Send your toughest science questions to fyi@popsci.com._

Can a Whale Get Rabies?

“It’s not as silly a question as you might think,” says Michael Moore, a marine-mammal research specialist at Woods Hole Oceanographic Institution in Massachusetts. “It would take some extraordinary circumstances, but any mammal can get rabies.” Bats, coyotes, foxes and raccoons are the most common carriers of rabies but, being landlubbers, it’s highly improbable that any of them would have a chance to bite and infect a whale. One of those animals could, however, bite a seal that’s resting on a beach, and then that seal could swim off and bite a whale. Although there is absolutely no record of a rabid whale, and only one documented case of rabies in a seal—a ringed seal caught in 1980 in Svalbard, an archipelago off Norway—the scenario may soon be of greater concern. “Starting 10 years ago, coyotes began to prey on harp seals here on Cape Cod,” Moore says. “Because of that, I like for my staff to get vaccinated. There’s a very small chance that a seal will have rabies.” Seals aren’t known to attack whales (it’s a size thing), but rabid animals behave erratically, so it could happen. Even if a rabid seal did bite a whale, it might take years for the whale to show symptoms. To become infected, the virus must travel along a nerve from the bite location to the central nervous system and brain. This is why a person bit in the face by a rabid fox will show symptoms earlier than if that person had been bitten in the foot. Rabies travels along nerves at a rate of 0.3 to 0.8 inches a day, so if a 50-foot-long whale was bit in the tail, it might take two to five years for the virus to reach the animal’s brain and manifest. What signs should one look for to identify a rabid whale? “Well, the telltale foamy mouth would be very difficult to spot in the water,” says Gregory Bossart, the chief veterinary officer at the Georgia Aquarium in Atlanta. “But as with other animals, rabies would interfere with any activity that involves the central nervous system, so a whale might exhibit abnormal swimming patterns or lose the ability to swim altogether. It might also have trouble with echolocation.” Watch out, then, for zigzagging whales bumping into stuff. Another classic symptom of rabies infection is hydrophobia, which would be quite difficult for a whale to deal with. “Who knows?” Moore jokes. “Perhaps that’s why whales strand themselves on beaches.” Try to stump us. Send your questions to fyi@popsci.com.

Which Organs Can I Live Without, and How Much Cash Can I Get for Them?

First, a disclaimer: Selling your organs is illegal in the United States. It’s also very dangerous. Handing off an organ is risky enough when done in a top hospital, even more so if you’re doing it for cash in a back alley. No, really: Don’t do this. OK? OK. There are many organs one can theoretically do without, or for which there’s a backup. Most folks can spare a kidney, a portion of their liver, a lung, some intestines, and an eyeball, and still live a long life. That said, donating a lung, a piece of liver or a section of intestines is a very complicated surgery, so it’s not done frequently on the black market. And no one’s going to make much cash on an eyeball. “In the U.S., there’s a fairly steady supply of donated corneas from corpses,” says Sean Fitzpatrick, director of public affairs at the New England Organ Bank. “There’s pretty much no market demand for eyes.” Giving up a kidney, though, is a relatively simple surgery that has netted desperate people a few bucks. Now, black-market organ dealers don’t do a great job of filing taxes, but here are some prices based on rumored deals and reports from the World Heath Organization. In India, a kidney fetches around $20,000. In China, buyers will pay $40,000 or more. A good, healthy kidney from Israel goes for $160,000. Don’t expect to pocket all that dough, though. “The person giving up the organ only gets a fraction of the fee,” says Sally Satel, a scholar at the American Enterprise Institute think tank who studies the prices paid by legal and illegal organ-donor operations. After the organ broker—the guy who sets up your kidney-for-cash transaction—takes his cut, he needs to pay for travel, the surgeon, medical supplies and a few “look-the-other-way” payoffs. Most people get $1,000 to $10,000 for their kidney (probably much less than you were hoping for). The best bet is to wait until compensation for organs is legalized in the U.S.—the Organ Trafficking Prohibition Act of 2009 would allow payment to donors, but it stalled in Congress—because there’s certainly a market for kidneys. Last summer, a man offering one of his for $100,000 (plus medical expenses) on Craigslist received several offers until the Web site removed his post. And you could probably hold out for even more. In 1999, before eBay delisted a kidney put up for auction, bidders drove the price up to $5.75 million. Send your science questions (sure, even the sketchy ones) to fyi@popsci.com.

What’s the Difference Between Artificial and Natural Flavors?

Picking barbecue-flavor potato chips over salt-and-vinegar can be tough enough without having to choose between brands made with “natural flavors” and ones that are “artificially flavored.” Natural flavors, you might think, are derived from the pure essence of a food’s flavor, and as such are more authentic. But the term “natural” is misleading. The Food and Drug Administration requires that natural flavors come from a natural material, but that’s a broad category. It usually means developing flavors from plant or bacteria by-products, or chemically treating naturally occurring molecules. Chemists then tinker with these to enhance their taste. The sweet strawberry taste of your naturally flavored ice cream? That probably started out as a bacterial protein. Artificial flavors, on the other hand, are just what you’d expect: taste-bud-stimulating chemicals concocted from scratch in labs. Although natural flavors have the potential to be more accurate and have layers of flavor, mucking with bacteria is expensive and the results are inconsistent. Controlling every step of a flavor’s development, as chemists do with artificial flavors, costs less and often hits closer to the mark. Flavor chemists can further enhance artificial flavors by stimulating your nose. “Aroma is often the dominant factor in flavor perception,” says Anuradha Prakash, a professor of food science at Chapman University and a spokesperson for the Institute of Food Technologists. “Flavorists can mix compounds with similar tastes but different aromas to maximize artificial flavor.” And despite the healthy sound of the phrase, natural flavors aren’t any better for you than man-made ones. In fact, in most cases your body can’t even differentiate between the two. Those barbecue chips? You’ll save a few cents with the artificially flavored variety, and they might even taste more like the real thing. Send your science questions to fyi@popsci.com.

Why Don’t Snowstorms Produce Thunder and Lightning?

Nearly every summer rainstorm comes with thunder and lightning. Yet during even the blusteriest blizzard, there’s nary a spark in the air. It can occur (although snow lightning strikes just six times a year on average in the U.S.), but winter air doesn’t make for prime lightning-forming conditions, says meteorologist Robin Tanamachi of the University of Oklahoma. During the summer, the lower atmosphere is full of warm, humid air. Above that, it’s cold and full of ice crystals. As the warm air rises, it carries water vapor with it, these molecules brush against the ice crystals, and this friction creates an electric field in the cloud — like scuffing your feet across a carpet. The ice crystals gain a slight positive charge, and the updraft carries them to the top of the cloud, giving the cloud’s bottom a net negative charge. Once the difference between the negatively charged cloud bottom and the positively charged ground becomes great enough, a bolt arcs between them. But in snowy months, the atmosphere is cold and dry throughout, so there’s no updraft to create friction within the clouds. Wind stirs the molecules and crystals some, but that action rarely generates a strong enough electric field to spark lightning. Got a science question nagging at you? Send it to fyi@popsci.com.

Why Are So Many Kids Allergic to Peanuts?

The number of school-age kids with peanut allergies has doubled in the past decade. Yet scientists can’t quite put their finger on what makes the legume such a threat or why the allergy has become so prevalent. Theories abound, though, and most involve an overactive immune system. “We have done such a good job of eliminating the threats that the immune system is supposed to manage, that it’s looking for something to do,” says Anne Muñoz-Furlong, CEO of the nonprofit Food Allergy and Anaphylaxis Network. Parents feed their kids more handy snacks these days, she says, and many of those contain peanuts or their derivatives. “We’re bombarding the immune system with these [food-based] allergens, so it’s attacking those instead.” Indeed, food allergies in general are on the rise. But peanuts seem to trigger especially violent immune reactions. This might be because they contain several proteins not found in most other foods, posits Robert Wood, an allergy specialist at Johns Hopkins University, and the structure of these proteins stimulates a strong immune response. Research suggests that roasting peanuts, as American companies do, might alter the proteins’ shape, making them an even bigger target. Allergy rates are lower in China, where it’s customary to boil peanuts, which damages the proteins less. (It’s worth noting, though, that China is also more polluted, so people’s immune system might be concentrating on traditional threats.) Typically, the immune system treats peanuts as safe, but some scientists believe that early and heavy exposure to peanut products might cause it to misidentify them as dangerous. This theory is strengthened by the fact that 8 out of 10 allergic kids have a reaction the first time they eat a peanut, indicating a previous indirect exposure, possibly even in the womb or through breast milk. Or maybe it’s all the videogames. Scientists think vitamin D, which the body needs sunlight to make, helps the immune system label substances as innocuous and thus build up a tolerance. Children who spend less time outdoors tend to be deficient in D, Wood says, so their body might mislabel peanut proteins as dangerous. Parents looking to protect their kids might consider sending them outside — and not washing their hands when they come home. Did you place a bet on a science question? We’ll help you settle up. Send your questions to fyi@popsci.com.

Why Do the Colorado Rockies Keep Their Baseballs in a Humidor?

Tune into a Colorado Rockies game, and you’re bound to hear one of the announcers mention the team’s most famous piece of lore: They keep their baseballs in a humidor. Cigar aficionados keep their cigars in a humidity-controlled environment to prevent the tobacco leaves from drying out, but the Rockies are more concerned about dried-out balls carrying farther and driving up scores. So far, it’s worked, having quelled the offensive binges the park was known for when it first opened. But scientists still can’t say exactly why it’s so effective. From the 1995 to 2001 seasons, National League pitchers at Coors Field recorded a horrendous earned-run average (ERA) of 6.50, more than two runs a game higher than the 4.37 ERA recorded at other stadiums. Fans and the media attributed the numbers to Denver’s mile-high thin air. But in the winter of 2002, based on a hunch that the balls might be drying out and losing weight in Denver’s arid climate, engineers at Coors Field installed a humidor for storing game balls. Since then, N.L. pitchers have posted a 5.46 ERA at Coors. According to a 2004 study by physicist David Kagan of California State University at Chico, keeping the balls at 50 percent relative humidity lowers their coefficient of restitution, a.k.a. bounciness. This means that the balls don’t bounce off the bat as powerfully as dried-out ones do. In December, Edmund Meyer and Alan Bohn, physics professors at the University of Colorado, found that the added moisture does not change a ball’s size and shape — and thus, its aerodynamics — which seems to verify Kagan’s explanation for the humidor’s success. Yet the pitchers might know something the scientists don’t. Former Rockies pitcher Shawn Chacon griped that pre-humidor balls were as slippery as pool balls, making it difficult to impart enough spin to execute breaking pitches. Lloyd Smith, a professor of mechanical engineering at Washington State University who tests bat materials, and physics professor Alan Nathan of the University of Illinois are investigating this effect and have qualitatively corroborated Kagan’s findings. “We’re fairly confident that the effects are small,” Smith says. “But in baseball, even small effects can be important.” Just ask the Rockies’ pitchers. _ Send your science questions to to us at fyi@popsci.com._

What Modifications Would I Need to Make to My Car So I Could Drive It On The Moon?

When the Apollo astronauts drove around on the moon, they had to settle for a little buggy. But if you want to tour the Sea of Tranquility in the family SUV or a Ferrari, well, you’re looking at more than a few weekends under the hood. “Your average car faces several major problems on the moon,” says Brian Wilcox, who heads the development of NASA’s new manned rover, called Athlete [see NASA’s Gilded Chariot]. Chief among those is the small matter of combustion. There’s no oxygen on the moon, so your engine can’t burn fuel to generate power. In addition, your rubber tires would crack or melt on the surface, where temperatures range from that of liquid nitrogen to boiling water. The upgrades are fairly straightforward. You could swap your Firestones for a set of NASA’s metal mesh lunar-grade tires. You’d need to get rid of that combustion engine, too. An electric engine running on hydrogen fuel cells would perform best in the lunar environment, Wilcox says. You’d want to keep your trips brief, though. On the surface of the atmosphere-free moon, there’s no protecting yourself from cosmic rays, which at lunar-intensity levels can increase your risk of developing cancer by 3 percent in just six months. If you’re the cautious type, you might consider two-inch-thick, water-filled panels to block the protons spewed from the occasional solar flare, which could kill you in less than an hour. Once you’d made these modifications, you would reap some nice benefits. Because gravity on the moon is one sixth that of Earth, your engine wouldn’t have to work as hard to propel your car, so you’d score six times as many miles per charge as you would here. And there’s never any traffic. Of course, you’d have to get your car up there. NASA’s going freight rate to the moon runs around $25,000 a pound, so delivering a one-ton car would cost $50 million. Those two-seater buggies left behind from the Apollo missions don’t sound so bad after all. Send your science questions to fyi@popsci.com.

What Fills the Space Left in Wells When Oil is Extracted From the Ground?

You might guess that magma or tumbling rocks fill the void, but the truth is much more prosaic: water. Petroleum deposits, which are naturally mixed with water and gas, lie thousands of feet below the earth’s surface in layers of porous rock, typically sandstone or limestone. (Contrary to what you might imagine, drilling for oil is more like sucking oil from a sponge with a straw than from a giant pool of liquid.) At such depths, these liquids are under very high pressure. Pump petroleum out, and the pressure in the well drops. Water in the surrounding rock, which is also packed under high pressure, then pushes its way into this low-pressure pocket until the pressure reaches equilibrium. “It’s just like digging a hole at the beach, where water in the sand around it flows into the lower pressure zone of the hole,” explains Chris Liner, a professor of petroleum seismology at the University of Houston. Unless you drill in a volcanically active region (which would be unwise), magma typically flows miles below the deepest oil wells, which tap out around 30,000 feet down. And although some shifting of rock and deep sediment can occur, it wouldn’t spur a major earthquake. Typical drilling-induced quakes register between –2 and –4 on the Richter scale, which is one thousandth as forceful as the rumble of a tractor-trailer driving by. Think you can stump us? Take your best shot. Send your science questions to fyi@popsci.com.

If The Sun Went Out, How Long Would Life On Earth Survive?

If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that. Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years. Millions of years after that, our planet would reach a stable –400°, the temperature at which the heat radiating from the planet’s core would equal the heat that the Earth radiates into space, explains David Stevenson, a professor of planetary science at the California Institute of Technology. Although some microorganisms living in the Earth’s crust would survive, the majority of life would enjoy only a brief post-sun existence. Photosynthesis would halt immediately, and most plants would die in a few weeks. Large trees, however, could survive for several decades, thanks to slow metabolism and substantial sugar stores. With the food chain’s bottom tier knocked out, most animals would die off quickly, but scavengers picking over the dead remains could last until the cold killed them. Humans could live in submarines in the deepest and warmest parts of the ocean, but a more attractive option might be nuclear- or geothermal-powered habitats. One good place to camp out: Iceland. The island nation already heats 87 percent of its homes using geothermal energy, and, says astronomy professor Eric Blackman of the University of Rochester, people could continue harnessing volcanic heat for hundreds of years. Of course, the sun doesn’t merely heat the Earth; it also keeps the planet in orbit. If its mass suddenly disappeared (this is equally impossible, by the way), the planet would fly off, like a ball swung on a string and suddenly let go. You’ve got science questions. We’ve got all the answers. Send your queries to fyi@popsci.com.

I’ve Heard That The Earth’s Rotation Is Slowing. How Long Until Days Last 25 Hours?

We could all use an extra hour in the day, but clocks won’t need to be extended anytime soon. The time the Earth takes to make a complete rotation on its axis varies by about a millionth of a second per day, says physicist Tom O’Brian of the National Institute of Standards and Technology. While some days are shorter than average, the planet’s rotation shows a long-term slowing trend, ultimately leading to a longer day. Scientists have reliable data on the Earth’s rotational speed, based on observations of the sun’s position in the sky during solar eclipses, going back some 2,500 years. Although the rotational rate hasn’t declined smoothly, over that period the average day has grown longer by between 15 millionths and 25 millionths of a second every year. Even at the faster rate, it will take 140 million years before the Earth’s rotation slows enough to necessitate a 25-hour day. You don’t need to worry about having to add another day to your calendar, either. Although the planet’s rotation around its own axis is lagging ever so slightly, we’re revolving around the sun just as quickly as ever, and showing no signs of slowing down. Need help with a science question? Send it our way: fyi@popsci.com.

Will We Run Out Of Breathable Oxygen If We Produce Too Much Carbon Dioxide?

Here’s why you might be worried: Burning oil, coal, gas, wood or other organic materials uses molecular oxygen, the O2 we breathe, to break carbon-hydrogen bonds and release energy. This reaction, better known as combustion, also pairs each broken-off, positively charged carbon atom with two negatively charged oxygen atoms, forming carbon dioxide, or CO2. Although that does cut into the amount of O2 in the atmosphere, there’s no need to fill your basement with oxygen tanks. Nitrogen accounts for 78 percent of the gas in the atmosphere, but molecular oxygen, the O2 that we breathe, is the runner-up, at 20.94 percent. The remaining 1 percent and change falls into the “other” category, predominantly water vapor but also argon and hydrogen gas; CO2 accounts for just 0.04 percent. Because of this relative bounty of oxygen, scientists such as Pieter Tans of the National Oceanic and Atmospheric Administration don’t fear that carbon emissions will cut off our oxygen supply. “Even if we were to burn another 1,000 billion tons of fossil fuels, we would only decrease the oxygen in our atmosphere to 20.88 percent,” he says. And even then, the effects that action would have on the environment—more particulate pollution, hotter temperatures—would be far worse than oxygen depletion. We’ll answer your science questions so you can breathe easy. Send them to fyi@popsci.com.

Could Tapping the Planet for Geothermal Energy Cool the Earth’s Core?

Global warming, holes in the ozone layer, and lush golf courses in the desert all reveal mankind’s ability to mess with the planet. But the Earth’s core, protected by an outer core consisting of some 1,000 miles of 8,000˚F liquid metal, appears safe from our meddling. Geothermal energy systems don’t drain heat directly from the core. Instead, they pull radiant heat from the crust—the rocky upper 20 or so miles of the planet’s surface—either by sucking up pockets of heated water or by circulating water through the hot rock. Power plants then use steam from the hot water to spin turbines to make electricity. Geothermal energy generates 7 to 10 billion watts worldwide, barely enough to account for 0.05 percent of global energy consumption and far less than the estimated 44 trillion watts the planet produces. But drawing energy from the crust won’t send it into a deep freeze: Its heat is constantly renewed by the virtually continuous decay of radioactive elements sprinkled throughout it. “Cooling the Earth’s core by drawing geothermal energy from the crust is like trying to cool the western end of Lake Superior with a few ice cubes,” says Paul Richards, a professor of natural science at Columbia University. It’s a good thing that we can’t cool the core. The spinning metal there generates Earth’s magnetic field, which protects us from deadly cosmic radiation. If the outer core cooled, the liquid would solidify, and both it and the solid inner core would grind to a halt, the magnetic field would dissipate, and high-energy cosmic radiation would bombard the planet, essentially turning Earth into a giant microwave and ending life on the surface. Send your science questions to the pros at fyi@popsci.com.

How Long Would it Take to Walk a Light-Year?

If you started just before the first dinosaurs appeared, you’d probably be finishing your hike just about now. Here’s how it breaks down: One light-year—the distance light travels in one year, used as the yardstick for interstellar distances—is about 5.9 trillion miles. If you hoofed it at a moderate pace of 20 minutes a mile, it would take you 225 million years to complete your journey (not including stops for meals or the restroom). Even if you hitched a ride on NASA’s Mach 9.68 X-43A hypersonic scramjet, the fastest aircraft in the world, it would take about 95,000 years to cover the distance. You’ll need to bring a big bag, too; walking such a distance requires substantial supplies. The average adult burns about 80 calories per mile walked, so you’d need two trillion PowerBars to fuel your trip. You’d also produce a heap of worn-out shoes. The typical pair of sneakers will last you 500 miles, so you’d burn through some 11.8 billion pairs of shoes. And all that effort wouldn’t get you very far, astronomically speaking: The closest star to the sun, Proxima Centauri, is 4.22 light-years away. Got something on your mind? Send your science questions to fyi@popsci.com.

Could Robot Aliens Exist? (We Asked an Astrobiological Philosopher)

The existence of a race of sentient alien robots might be not just possible, but inevitable. In fact, we might be living in a “postbiological universe” right now, in which intelligent extraterrestrials somewhere have exchanged organic brains for artificial ones. The driving factor is a pragmatic desire to improve mental capacity. Alien beings may have already reached a point in their evolution where, having exhausted the potential of their biological brains, they have taken the next logical step and opted for robotic brains equipped with artificial intelligence. This brain swap may not be as far off for humans as one might think. In only a few decades, the computer revolution here on Earth has produced supercomputers capable of performing more than a quadrillion calculations per second. (According to research by Hans Moravec, an artificial-intelligence expert at Carnegie Mellon University, that rate trumps the human brain’s estimated top speed of 100 trillion calculations per second.) Some scientists speculate that in a few decades, an event called the technological singularity will occur, and machines armed with computer brains will become sentient and surpass human intelligence. Civilizations equipped with technology light-years ahead of our own could have already experienced the singularity thousands, or even millions, of years ago. How likely is it that such a robotic race exists? Given the limitations of biology as we know it, the force of cultural evolution, and the imperative to improve intelligence, I’d say the chances are greater than 50/50. That said, if postbiological beings do exist, they might not be interested in us at all. The gulf between their minds and ours might be so great that communication is impossible, or they might consider meatheads like us too primitive to warrant their attention. Image courtesy of Paramount/Everett Collection Send your science questions to fyi@popsci.com.

The Large Hadron Collider

Physicists hoped that the LHC would deliver an undiscovered particle, but the signal faded out after a few months of analysis.

Will Drinking Carbonated Beverages Weaken My Bones?

Maybe—but only if you’re drinking several gallons of seltzer a day. Here’s the chemistry that has soda drinkers worried: As carbon dioxide hits the water in your blood, it turns into carbonic acid. Too much acid in the blood can lead to a condition called acidosis, which could intercept small amounts of calcium from food as it makes its way to your bones, or steal it from them directly. Your greater concern, though, says endocrinologist Robert Heaney of Creighton University, should be the vomiting, headaches and impaired organ function that result from extreme acidosis. The acid content in a carbonated beverage is 5 to 10 percent of what the body’s metabolism naturally produces, Heaney has found, which is far too little to interrupt the calcium absorption of bones. In general, he says, the carbonation in soda has no ill effect on bone-mineral content. Other ingredients in soda might rob a small amount of calcium from bones. Caffeine causes the kidneys to pull sodium from the blood using proteins that accidentally scoop up calcium ions as well. The body reverses this effect within 24 hours, however. Another commonly cited culprit is phosphoric acid, an ingredient in colas. Studies have indicated that if the ratio of phosphorus to calcium in your body tips too far toward phosphorus, it can cause bone loss over time. So although a “Coke and a smile” once in a while won’t a brittle bone make, Heaney urges drinking a tall glass of milk to keep your bones good and strong. Science questions keeping you up at night? Send them to fyi@popsci.com.

Are Records Really Better?

Sorry, vinyl aficionados, but CDs most accurately capture the clarity of musical performances. If you look at the grooves of a standard long-play record, or LP, through a microscope, you’ll see that each is filled with what look like rolling hills. These are, in fact, an extremely close replication of the shape of the sound waves from the musician’s instrument. But because the needle that carves the groove is shaped slightly different than the needle that reads it, the LP will never sound exactly like the original performance. (Not to mention that changes in temperature and humidity warp vinyl over time.) The mathematical data encoded on a CD, however, is a nearly exact representation of the original sound. Comparing an LP and a CD made from the same microphone signal, the LP’s groove must perfectly match the signal to sound close to CD-quality, which is almost impossible, says Stanley Lipshitz, who studies electro-acoustics and digital-signal processing in the Audio Research Group at the University of Waterloo in Canada. Even so, some audiophiles claim to hear a natural sound, vaguely described as “musical warmth,” when listening to vinyl. What they’re hearing, Lipshitz says, is most likely the deficiencies of the record player. Sound waves from the speakers and the needle’s rise-and-fall passage over the grooves cause the LP to vibrate. The needle picks up these extra vibrations and adds them to the music, creating the “fullness” that’s associated with LPs. “Some people mistake this defect for a virtue,” Lipshitz says. But when it comes to portable music, people stuff their iPods with tunes of far worse quality than either CDs or LPs. MP3s are compressed files that cut as much as 90 percent of the sound from the original recording, by using computer models of human hearing and removing subtle sounds that most of us don’t realize we’re missing. A compressed recording of a French horn, for example, might lack the slight reverberations from the concert hall. Instead of filling his digital music player with thousands of songs of crummy sound quality, Grammy Award–winning producer Jim Anderson keeps his iPod stocked with just 55 songs in an uncompressed format, including jazz pianist Keith Jarrett’s epic live solo concerts in Germany. (Anderson prefers the lossless AIFF format, in which one minute of stereo audio occupies 10 megabytes.) “If I were to cut the CD down to an MP3, I’d be throwing out all the stuff in the room that makes the piano sound as full as it does,” says Anderson, who is also chair of the department of recorded music at New York University. “I hear the piano exactly as it was at the concert.” Burning question? Send it forth to the experts at fyi@popsci.com

Antibacterial Soap Kills 99.9 Percent of Germs. Should You Worry About That Other 0.1 Percent?

Your dirty hands can harbor millions of germs, but simply washing your hands with regular soap—making sure you vigorously rub them together for 30 seconds—will slough enough microbes down the drain to cut that number to the tens of thousands. Assuming you don’t then lick your hands, you’re probably safe at this point, but there’s still some risk. “Most pathogenic organisms cause disease when the numbers ingested are in the thousands to 10,000,” says Dial Soap’s manager of microbiology, George Fischler. Dial lab tests have shown that antibacterial soap, which most frequently uses the germ-killing agent triclosan, will, if used properly, reduce the number of germs on your hands to a few thousand. But Allison Aiello of the University of Michigan School of Public Health isn’t convinced. Her lab, she says, has found no germ-killing benefit from triclosan over regular soap alone, even after three minutes of scrubbing. If you’re worried about runoff from antibacterial hand soap creating super-bacteria, your drainpipes are safe. Aiello and her colleagues have identified only a few bacterial strains resistant to triclosan or other household antibacterial products, and those were only in controlled laboratory settings primed for growing bacteria. Got questions? Science questions? Sweet. Send them to fyi@popsci.com.

What Do Whales Sing About? (We Asked an Interspecies Musicologist)

Humpback whales sing some of the most beautiful songs in the animal world. It’s not just “woo, woo, woo”—their songs last 10 to 15 minutes and have a definite form, usually consisting of five or six unique phrases. Only the males sing, which has led many scientists to theorize that they croon to attract females. The hole in this argument, though, is that no one has ever seen a female whale show any interest in a male’s song. Although male songbirds change their tunes to impress potential mates, a group of male humpbacks all sing the same song. If the song changes midseason, they all adopt the same change. We don’t really know why they do this. They might be trying to create a sense of peace before they mate, or they could be staking out their territory. Either way, it makes the competitive-mating theory seem less believable. We’re also not quite sure why they change their songs at all. It could be that one whale tweaks part of the song and, if it’s catchy, the rest pick it up quickly. I gave this a shot by playing my clarinet to a whale swimming under my boat, and he seemed to change his song in response. Another theory is that whales’ brains are programmed to change the tunes. For example, scientists have recorded humpbacks in Hawaii and the Gulf of Mexico altering their songs in similar ways at the same point in the mating season, even though there’s no way the groups could be hearing each other’s songs. Most of the research money goes to studying whale songs for conservation efforts (each whale has a unique voice, so it’s a good way of estimating how many are out there), not translating their meaning. But this much seems clear: If it takes 15 minutes to sing it, the message probably isn’t too urgent. David Rothenberg is a professor of philosophy and music at the New Jersey Institute of Technology and analyzes whale songs in his new book, Thousand Mile Song. _ Send your science questions to fyi@popsci.com._

Could a Moon Have Moons?

Astronomers can say with near certainty that there are no moons with moons in our solar system. But that doesn’t mean it’s physically impossible. After all, NASA has successfully put spacecraft into orbit around our moon. Although astronomers have spotted some asteroids with moons, a parent planet’s strong gravitational tug would make it difficult for a moon to retain control of its own natural satellite, says Seth Shostak, a senior astronomer at the nonprofit SETI Institute. “You would need to have a wide space between the moon and planet,” he says. Orbiting far away from its parent planet, a relatively massive moon might be able to hold onto a moon of its own. Conditions like these might exist in far-off solar systems, but while some 250 exoplanets have been detected, there’s almost no chance we’ll be able to spot exomoons, much less moons of exomoons, for decades to come. This is because our current methods for planet-hunting—such as spotting one as it passes a large star—lend themselves to detecting mostly huge, Jupiter-like planets, not their moons. Even if astronomers spot a moon with a moon, it probably won’t last long. “Tidal forces from the parent planet will tend, over time, to destabilize the orbit of the moon’s moon, eventually pulling it out of orbit,” says Webster Cash, a professor at the University of Colorado’s Center for Astrophysics and Space Astronomy. “A moon’s moon will tend to be a short-lived phenomenon.” Have a burning science question? Send it on to [fyi@popsci.com](mail to: fyi@popsci.com)

Who’s Better at Giving Directions, Men or Women?

He says go straight for three miles and turn east. She says drive past the school and turn right at the green house. Both sets of directions will get you to the same grocery store just as easily, but they embody the language barrier between the sexes that lurks behind many a front-seat argument. Deborah Saucier, a professor of neuroscience at the University of Lethbridge in Canada, examined the differences in phrasing in her 2003 study. She observed that, after studying a map and being asked how to get to various locations, women typically give directions that feature landmarks and left and right turns. Men, on the other hand, employ compass directions and distances measured in minutes or miles. Some animals, such as homing pigeons, have extra iron in their nose that helps them turn toward the magnetic north pole. But men’s internal maps, Saucier theorizes, most likely date back to our hunting ancestors. During a hunt, men would stray far from home and into unfamiliar territory to bring down wild animals. They may have relied on tracking the position of the sun and their innate orientation skills to find the most direct route home. Meanwhile, prehistoric women, who gathered more-sedentary food, probably found their way to and from the most bountiful and nutritious plants with the help of landmarks. In a study last year at the University of California at Santa Barbara, evolutionary psychologist Joshua New tested this theory in a farmers’ market. After a single tasting tour of the market, women could more accurately point to food stalls they had visited, noting, in particular, the locations of foods with high energy content. With the benefit of food stalls as landmarks, women knew their way around better than men. To compensate for the gender differences, Saucier suggests giving disoriented people both male- and female-oriented instructions. “People get a lot less lost that way,” she says. Settle it already. Send your science questions to fyi@popsci.com.

What’s the Biggest Thing a Carnivorous Plant Will Eat?

Carnivorous plants generally stick to a diet of bugs that they ensnare. On rare occasions, though, tropical pitcher plants—which drown and break down prey in vase-shaped traps that can be smaller than a little finger or larger than a football—have been found holding the skeletal remains of frogs, geckos and even small rodents. But what about human flesh? Chowing down on a vertebrate is incredibly dangerous for the plant, says Barry Rice, conservation director for the International Carnivorous Plant Society and author of Growing Carnivorous Plants. It takes a long time to digest meat, so the meal could rot prematurely, killing the trap. That’s not to say that a giant meat-eating plant wouldn’t have a taste for humans. While recovering from a case of athlete’s foot, Rice fed infected skin to Venus flytraps to see if they would eat it. A week later, he was astonished (and a bit appalled) to find barely a trace of his skin remaining in the traps. Healthy skin and internal organs would probably meet the same end, Rice predicts. “I’m still fond of my fingers, though,” he says, “so I’m not taking the experiment to the next level.” Send your science questions to fyi@popsci.com.

Do Cells Make Noise?

You have to listen very, very closely, but yes, cells produce a symphony of sounds. Although they won’t win a Grammy anytime soon, the various audio blips produced by cells are giving scientists insight into cellular biomechanics and could even be used to help detect cancer. Researchers at the University of California at Los Angeles studying baker’s yeast cells discovered that the cell walls vibrate 1,000 times per second. These motions are too slight and fast to be caught on video, but when converted into sound, they create what the scientists describe as a high-pitched scream. (It’s about the same frequency as two octaves above middle C on a piano, but not loud enough to hear with the naked ear.) “I think if you listened to it for too long, you would go mad,” says biological physicist Andrew Pelling, now at University College London. Pelling and Jim Gimzewski, his adviser at UCLA, theorize that molecular motors that transport proteins around the cell cause the walls to vibrate. So far, scientists have not observed mammalian cells that audibly shimmy on their own, at least in part because animal cells’ wiggly membranes are less likely to vibrate than the sturdy cell walls of yeast and plants. But human cells certainly squeal when zapped with light. When Richard Snook and Peter Gardner, biologists at the University of Manchester in England, blast human prostate cells with infrared light, their microphones pick up thousands of simultaneous notes generated by the cells. Through statistical analysis of these sounds—which are created as the cells rapidly heat up and cool down, causing vibrations in the air molecules directly above them—Snook and Gardner can differentiate between normal and cancerous cells. “The difference between a healthy cell and a cancer cell is like listening to two very large orchestras playing their instruments all at the same time,” Gardner says. “But in the cancerous orchestra, the tuba is horribly out of tune.” Gardner is fine-tuning the technique in hopes of replacing current, unreliable pre-biopsy prostate-cancer tests. His ultimate goal is to reduce the number of prostate biopsies performed, 75 percent of which come back negative. Don’t be shy, now. Send your questions to fyi@popsci.com.

Is There Any Scientific Evidence to Explain Why the Dumb Guys Always Seem to Impress the Ladies?

Although many jilted brainiacs might beg to differ, there’s no concrete evidence that women are more attracted to dumb men. Yet the same might not be true for some of our mammalian cousins. Consider, for example, the bat. After gathering available brain and testis size data for 334 species of bats, evolutionary biologist Scott Pitnick of Syracuse University found that males with the biggest cranial capacity were likely to have the smallest testicles, and vice versa. Why does this tradeoff occur? Both brain and testis tissue are physiologically demanding to grow and maintain. Because bats´ high metabolism and near-constant movement doesn’t leave them much energy to spare, many species have evolved to favor one organ over the other. Testes tend to be the largest in species wherein females are especially promiscuous-size (and, thus, sperm counts) has the advantage when sperm from several males are competing in the reproductive tract. “The question is, do you get your genes to the next generation by being clever or by getting busy?” Pitnick says. Because humans aren’t living as close to the energetic knife edge, he adds, they haven’t faced the same evolutionary dilemma. This could mean that, for humans at least, having a big brain is a more important evolutionary advantage than producing a lot of sperm. “People ask me if this means Albert Einstein had tiny testes,” Pitnick says, “and that’s not necessarily true.” Did you place a bet on a science question? We’ll help you settle up. Send your questions to fyi@popsci.com.