Though the steam-generating autoclave has long been the standard method of sterilizing medical equipment, this could change with the solarclave, a new solar-powered device developed by engineers at Rice University.

The research team designed the solarclave to function without an external electricity source. Though MIT created a similar device, this is the first to pass FDA sterilization tests. The device could be especially useful in developing countries with limited access to reliable power supplies, where people are disproportionately likely to contract bacterial infections.

In contrast to autoclaves that require electricity to produce steam, the solarclave uses sunlight and recyclable metal and carbon nanoparticles. When mixed into an aqueous solution, the nanoparticles absorb energy more quickly than the surrounding liquid. As sunlight collects into a mirrored dish, the solution heats up and converts the water molecules into steam. The device is very efficient: it uses only 20 percent of its energy to gear up to this point. The other 80 percent is spent sustaining the steam.

The team created two prototypes, each of which was tested on its ability to kill Geobacillus stearothermophilus, a bacteria notoriously difficult to destroy with heat. Within 30 minutes, both solarclaves had killed their entire samples.

This type of device could eventually be used to purify water or even generate electricity, the researchers predict.

The swift strike of a match on July 4 typically precedes sky-high spectacles. But matches themselves can be fireworks. When ignited, the bulb of fuel on a match's tip combusts into space-hogging gases. By containing the gas in aluminum foil and directing it downward, you can create a miniature missile. Follow these steps to become a rocket scientist in your own driveway.

Materials

• Matches
• Sewing pin or needle
• Paper clips
• Aluminum foil

Instructions

1. Bend a paper clip into a 45-degree angle. Presto! You have a launch pad.
2. Lay a pin along a matchstick so that the sharp tip touches the match head. Wrap the head with a piece of aluminum foil, and gently crease the foil around the pin (avoid tears and holes).
3. Remove the pin. This leaves a hollow channel that will direct gas downward, so it can act as propellant.
4. Rest the match on the launch pad, hold a small flame under the foil-wrapped match head, and start your countdown.

Time: 10 minutes
Cost: About $3
Difficulty: Easy

WARNING: Kids, you need adult supervision. Launch only outside while wearing eye protection, and mind your aim (matches were designed to start fires).

This article originally appeared in the July 2013 issue of Popular Science. See the rest of the magazine here.

How Strong Can Someone Become?

Inspired By Man Of Steel

THE PLOT: In the latest remake of the 75-year-old comic franchise, Superman, an innocent farmer's son, discovers his powers and saves the planet from two deranged villains, General Zod and his henchman, Faora, who arrive from Krypton bent on destruction.

THE ANSWER: Superman may be able to lift a bus or an oil platform, but humans come with pretty strict limits on strength, the first of which is the nature of muscle. The maximum force that humans produce depends on how our muscle fibers work. Over the years, scientists have extracted muscles from different vertebrates and tested their capacities. What emerged was a nifty rule of thumb: A muscle can produce about 30 newtons of force (or 6.75 pounds) for every square centimeter in cross-section. "By virtue of evolution being a conservative process, the components of all these muscles are basically the same," says Peter Weyand, an applied physiologist at Southern Methodist University in Dallas.

So why not just create more muscle? To a degree, humans have been doing that for ages: We're more physically developed than we were even 500 years ago. But, says Geoffroy Berthelot, a sports analyst, "You can't increase the mass of your muscle over a certain limit because your bones will not support its strength." Tendons, while quite sturdy, have limits too-15,000 pounds of pulling per square inch across. Berthelot says that humans may be approaching the upper bounds of athletic performance.

Muscle composition limits human performance as well. Fast-twitch muscle fibers produce more power than their slow-twitch counterparts. With training, athletes may be able to alter their ratio of slow-to-fast, but research suggests it is mostly genetically predetermined.

One way to raise the limit on human strength is to engineer an athlete that is, well, beyond human. A different bone structure could increase the leverage of certain movements. For example, according to Duke University evolutionary anthropologist Steven Churchill, male Neanderthals, when flexing at the elbow, were probably one-third stronger than average men today. So when considering Superman, it's worth remembering his origin on Krypton. Like a Neanderthal, he is not technically human but humanoid, so different rules apply.

HEALTHY SKEPTICISM: Superman's suit is just about as indestructible as the man of steel. Comic-book writers have said its strength resulted from a force field or Kryptonian textiles, but that always rang hollow. The only way to make a bulletproof bodysuit would be to reinforce it with graphene, which is flexible, ultrathin, and 50 times stronger than steel.

Why Bother Controlling A Robot With Your Mind?

Inspired By Pacific Rim

THE PLOT: When colossal monsters called kaijus emerge from the depths of the Pacific Ocean, humanity tries to fend them off with giant battle bots controlled by pilots linked to neural interfaces.

THE ANSWER: Well, sure. You could use a tried-and-true interface, as drone pilots do. But a brain-controlled interface (BCI) is much cooler. And in principle, it's better: As any gamer knows, there is a biochemical limit to how fast a brain signal can travel to a muscle, and when battling kaijus, every millisecond counts.

That said, scientists are a ways from that point. BCIs exist-scientists have used them to control robots-but they are pretty clunky. It is difficult to get a clear signal from a brain-wave pattern, which leads to errors and can slow response. "We're very careful when we talk about BCI," says Francisco Sepulveda, a bioengineer at England's University of Essex who worked on neural interfaces for 20 years. "It wouldn't be a standalone solution except in specific cases."

Better BCIs, for example, may one day allow quadriplegics to move about or help pilots immobilized by high gravitational forces. But even in those capacities, BCIs could be of limited utility; scientists could more easily create an interface that responds to voice commands or eye movements, or they may not need an interface at all. When it comes to planes or cars (or 2,700-ton robots), autonomous controls are likely a better option.

For those pursuing BCIs, the pilots in Pacific Rim do present a useful idea: They drive their battle bots in pairs, with their brains linked by a "neural bridge." Sepulveda's group just finished an experiment on this concept. Participants were divided into teams of two, and software read brain signals from both team members as they tried to run a spacecraft simulator. By merging neural signals, the BCI averaged out some noise and flew with greater accuracy. Turns out two heads are indeed better than one.

HEALTHY SKEPTICISM: According to production stills, the kaiju'sblood runs blue, which is odd but not unheard-of. The horseshoe crab, among other arthropods, has bluish blood. Its blood cells use proteins made from copper instead of iron to carry oxygen. Its blood also clots easily, which allows the crab, and presumably the kaijus, to recover quickly from wounds.

Will We Ever Swap Perfectly Lethal Guns For Fancy Phaser Pistols?

Inspired By Star Trek Into Darkness

THE PLOT: In the sequel to the 2009 J.J. Abrams film, a terrorist bombing in London triggers a planet-hopping manhunt for a traitorous Federation agent-and a climactic space battle between the turncoat's vessel and the USS Enterprise.

THE ANSWER: Since it debuted in 1966, the Star Trekphaser has remained the stuff of Hollywood prop departments and Trekkie conventions. But directed-energy weapons may be coming to the battlefield soon. Boeing, for example, is developing the truck-mounted 10-kilowatt HEL MD (high-energy laser mobile demonstrator) to defend against swarms of incoming drones, missiles, or mortar rounds. Instead of launching a million-dollar-plus missile for every threat, defense experts could use lasers to destroy multiple targets with precision. Though smoke can dampen a beam's intensity, lasers don't have to account for wind speed or range, and they don't ricochet, limiting any collateral damage.

Boeing is also testing a smaller unit called the Tactical Laser System. While still far from holster-size, it could be mounted on naval vessels alongside an Mk 38 machine gun. The objective would be to defend against drone swarms or a fleet of smaller boats, either by destroying them outright or by using lower-intensity beams to blind or fry sensors (or eyeballs).

Where ray guns become unworkable is on smaller scales. For example, Boeing is working on a portable 2kw laser, capable of destroying unspecified targets (the company won't go into details). But even this weapon is not small enough to replace the trusty assault rifle; it requires two soldiers to carry it. The laser would be most useful for stealth missions, since it could be set in place and fired remotely, with minimal light and sound.

The greatest challenge in making handheld directed-energy weapons is the energy itself. A 100kw laser can consume two cups of diesel in a four-second engagement. That's a bargain compared to launching missiles. But a general-purpose, infantry-scale death ray would require fuel with an energy density that today's researchers can only dream of. "We're not close," says Suveen Mathaudhu, a materials engineer in the U.S. Army Research Office. To create that, he says, "would require a major, major breakthrough, on the level of fusion technology."

HEALTHY SKEPTICISM: At one point in the film, Spock attempts to extinguish a volcano with something like a super ice cube. To quench an eruption, though, you'd need to solidify the magma all at once, says Erik Klemetti, a vulcanologist at Denison University. That would require instant cooling on a massive scale; anything less would only create lots of steam, which would just intensify the eruption.

Will Exoskeletons Ever Fly?

Inspired By Iron Man 3

THE PLOT: Rakish billionaire, inventor, and superhero Tony Stark faces a series of attacks-including an air strike on his home and wrestling matches with nanotech-enhanced goons-launched by an international terrorist who calls himself the Mandarin.

THE ANSWER: In Iron Man, Tony Stark's suit is incredibly powerful, a wearable weapon system that can hurl cars and outmaneuver jet fighters. In reality, it is the synthesis of two technologies: the jetpack and the exoskeleton, which is the more promising of the two. In terms of exoskeletons, no one will be bench-pressing Buicks anytime soon, but a number of systems already exist as assistive or rehabilitative medical devices. Companies such as Argo Medical Technologies and Ekso Bionics offer motorized devices targeted to the disabled that can essentially walk for their wearers, allowing users a more versatile alternative to wheelchairs. There could be other applications for exoskeletons, too. At NASA, researchers are working to incorporate them into space suits. They have developed one that could eventually allow astronauts to hike across Mars for long stretches, loaded with gear, while expending little energy.

Meanwhile, the development of rocket belts (the technical term for jetpacks) is at a relative standstill. A handful of models have debuted in the past decade-including Jet Pack International's H202 and TAM's Rocket Belt-but none have amounted to more than a PR stunt. The systems struggle to stay aloft for a useful amount of time, emptying fuel tanks in less than a minute. The additional weight of an exoskeleton would only exacerbate the problem.

As for the future of exoskeletons, NASA engineer Chris Beck says that today's systems, such as the X1 that he's developing, will lead to the superhuman systems of tomorrow. "We're not just blowing smoke. An exo like ours, or an adapted version, could be used for strength augmentation," he says. Exoskeletons might also fly-just not with jetpacks. "What if you combined ultralight planes and our auto-balancing techniques?" says Larry Jasinski, CEO of Argo, whose ReWalk exo is for sale for personal use in Europe and Israel. Instead of a pilot's seat and a traditional control layout, the flier might simply squeeze into the aircraft's integrated suit. "You could literally lean left or right, and the exoskeleton components could steer for you."

HEALTHY SKEPTICISM: Iron Man's jet boots work underwater, which ignores the fact that combustion-based jets drown when submerged. DARPA sought proposals for submersible aircraft in 2008, but that project, it seems, is dead in the water.

Can Humans Survive On A Permanent Orbital Colony?

Inspired By Elysium

THE PLOT: In 2154, the wealthiest humans live on a posh orbital station called Elysium. One man tries to harness the upper crust's lifesaving technology to save the poor, disease-ridden masses still on Earth-starting with himself.

THE ANSWER: Spectacular views notwithstanding, living in space is hard. Microgravity drains the mass from our flesh and bones, and the radiation normally blocked by Earth's magnetosphere can shorten lifespans. So the premise of Elysium presents a conundrum: Why would the planet's most pampered occupants pay to live in orbital habitats that turn them brittle and cancerous?

In the film, the answer is that money cures everything. The station's health care exceeds anything on Earth, with devices that erase nearly all physical ailments, including cancer. As for the hazards associated with low gravity, Elysium is a Stanford torus, a design first proposed in the 1970s, where inhabitants live on the interior of a gigantic, rotating wheel, with centrifugal force providing Earth-equivalent G-forces.

In theory, the torus is scientifically sound, but building it might be impossible. It would require hauling millions of tons of material into orbit. "It might literally be easier to colonize the moon than to construct this Stanford torus," says John B. Charles, chief of human-research programs at NASA. It could also be difficult to innovate away the health threats associated with living at the edge of Earth's magnetosphere. Present-day astronauts can absorb two to three years' worth of radiation aboard the International Space Station, in multiple stays, before being grounded. According to Charles, a more permanent habitat would most likely use available materials such as wastewater to deflect radiation. In the end, it would take a lot of work just to avoid wasting away. Hope that view is worth it.

HEALTHY SKEPTICISM: Matt Damon's rifle-size railgun should raise some eyebrows. The benefit of supplying some 100,000 amperes per electromagnetically propelled shot is a longer range. That might make sense for a ship-mounted weapon, like the one the U.S. Navy is conceiving. For gunfights that don't span miles, though, gunpowder is more practical.

This article originally appeared in the July 2013 issue of Popular Science. See the rest of the magazine here.

There's been speculation for decades about whether gender splits among offspring are truly random. Is it really just complete chance whether you'll end up with a male or female? A new study led by a Stanford University researcher suggests that it isn't random at all--it's an evolutionary strategy.

It's unclear why-or how-a mother mammal might choose to produce offspring of only one gender. But the data seems to suggest that there is indeed a valid reason to have only males or only females, and that lots and lots of animals seem to obey those reasons. The basic impulse: mothers will "choose" whichever gender is likely to produce the most grandchildren.

The study looked at thousands of animals at the San Diego Zoo, because to figure out whether gender splits have an effect on number of grandchildren, you need to have detailed records of three generations. To make sure their results wouldn't be influenced by a particular species' quirks, the study looked at all kinds of different mammals, from primates to buffalo to horses to bears.

They found that mothers who had either mostly males or mostly females ended up with more grandchildren than mothers whose offspring had an even gender split. Mothers that produced significantly more males tended to do drastically best, while mothers that produced significantly more females also beat the even gender-split mothers, but not by quite as much.

That little quirk is explained by Joseph Garner, the author of the paper. He suggests that having mostly males is a high-risk, high-reward situation; for many species, only the alpha male gets to breed. If you happen to give birth to an alpha male, sweet, you've got tons of grandkids. If not, you've got none.

Garner speculates that environmental factors may trigger the involuntary selection of sperm that would produce a certain gender. If it's been a good year for food, and the mother is plump and happy, she's got a better chance of producing a successful, strong male. If not, well, maybe it's best to go with a female, since their reproductive success depends less on health and vigor.

The study, to be frank, has an awful lot of supposition based on correlation. The fact that it took place entirely in a zoo makes me a bit nervous, as animals very rarely reproduce in zoos the same way they do in the wild. But it's a really interesting branch of study, that's for sure.

The study appears in the current issue of PLoS One.

When HTC released a gorgeous, powerful, innovative, distinctive Android phone a few weeks ago, we realized Android was suddenly an option for everyone, even the very rich. But yesterday, Nokia unveiled its newest flagship smartphone, a gorgeous, powerful, innovative, distinctive Windows Phone, and I suspect it won't sell any better than the Lumia 920, the last flagship Nokia Windows Phone (which in its first quarter sold 4.4 million units, compared to the iPhone 5's 27.4 million). Or the Lumia before that. Or the one before that. That's because Windows Phone has a serious problem: its hardware is improving rapidly, but its operating software is not.

Two years ago, we reviewed Windows Phone 7.5, the first major update to the then-new Windows Phone operating system, and said we were still "waiting for it to really live up to its promise." One year ago, we reviewed the Nokia Lumia 920, with the Windows Phone 8 update, and said "Windows Phone has huge problems. That doesn't mean it's bad, but we're two years into this operating system, and it still has basic issues that impact daily use."

The new Lumia looks great--I was very impressed with the camera technology when I saw it last year, and the aesthetics of the Lumia line have always been stylish and playful in a way that's totally different from anything else on the market. But that doesn't matter at all, because Microsoft is not improving the Windows Phone operating system at anywhere near the pace it needs to. Here's a brief list of major problems Microsoft has yet to address.

• Multitasking is sometimes inscrutable, in that you never know which apps will show up in the "currently running" list of apps.
• Email threading often doesn't work, especially with Gmail accounts.
• Lots of features, including Rooms (sort of a mobile, multimedia chat room) are Windows Phone exclusives, meaning they can only be accessed with Windows Phones--cool, but it's pretty unlikely all your friends have Windows Phones too.
• Speech recognition is lousy, nowhere near as good as Google's Android voice control or even Apple's Siri.
• There's no place to see notifications at all; if you get an alert on an app that you haven't pinned to your homescreen, you'd never know.
• Bing Maps doesn't have public transit directions, let alone bike directions.
• It's not easy to share photos to services like Twitter and Facebook; Android and iOS let you do that in one touch, but not Windows Phone.

Microsoft can fix all that stuff. Microsoft needs to fix all that stuff. But the biggest problem might be the hardest to fix: there aren't nearly enough good apps available for Windows Phone.

App developers are often low-budget and understaffed, even wildly successful ones, and it's expensive and time-consuming to assign people to port apps to another platform, like Windows Phone. They'll do it, sure, if they have the resources and it seems like the userbase is big enough to make them some money... and therein lies the problem.

It's a cyclical issue. Developers won't make apps for a platform nobody uses, and nobody will buy a phone with no apps. No customers leads to no apps leads to no customers.

Microsoft can break the cycle, though. All it has to do is take advantage of the fact that it's one of the biggest and most powerful companies in the world: take a cannon, fill it up with money and talented developers, and aim it south from the Microsoft campus in Redmond, Washington straight at Silicon Valley. (Or wherever else the developers call home.) Aim the cash cannon east, at London, and give King.com, the makers of massive hit Candy Crush, a couple hundred thousand dollars and a team of developers to port the game over to Windows Phone. Do the same for Instagram (which is still not available on Windows Phone), Snapchat, Dots, or whatever else people are using on other platforms.

Microsoft has the clout and capital to fix its own problems--it just needs to actually spend the time and money it'll take to do it.

We've seen 3-D printed aircraft and drone parts, and even plans for a printable private jet. Now NASA has demonstrated another 3-D printing first: The agency has just finished successful tests of a 3-D printed rocket engine injector at the Glenn Research Center in Cleveland, Ohio, marking one of the first steps in using additive manufacturing for space travel.

In conjunction with rocket manufacturer Aerojet Rocketdyne, NASA built the liquid-oxygen and gaseous-hydrogen rocket injector assembly using laser melting manufacturing. This sci-fi-sounding technique involves melting metallic powders down with high-powered laser beams, then fusing them into shape. Previous manufacturing methods for these type of injectors required more than a year. Being able to 3-D print the parts reduces the time frame to four months, at a 70 percent price reduction.

Eventually, 3-D printing is likely become a staple of the aerospace industry, as Davin Coburn describes in our July issue.

NASA has already expressed interest in putting 3-D printers in space, so astronauts could have easier access to spare parts and, most importantly, pizza.

Michael Gazarik, the associate administrator for space technology at NASA, even suggested entire spacecraft could one day be made with 3-D printing, calling it "game-changing for new mission opportunities."

This article was originally published on January 17, 2013.-Eds.

Q: What is the 787 Dreamliner and why do we care?
A: The Dreamliner is a massive jet from Boeing, the company's most fuel-efficient airliner and the first major airplane to be made with composite materials--specifically, carbon fiber reinforced plastic. It's made of 80% composite by volume, which makes it much lighter than typical planes without sacrificing strength, and has a lot of nice consumer-facing features--bigger windows, new noise reduction techniques, modular bathrooms, and more space for passengers. It'll hold up to 296 passengers, too--this is a big boy. It's not a revolutionary plane, but we all care about it because it's the next evolution of the planes we'll all take. You probably won't fly on an all-electric plane any time soon, but you probably will fly on a Dreamliner.

Q: Cool! So how come I can't catch one flying out of my local airport tomorrow?
A: Well, here's the thing about the Dreamliner: it's been plagued with more serious problems than any other major new jet line in recent memory. Its batteries have a tendency to catch on fire. Earlier this week, both Japan Airlines and the FAA grounded all Dreamliners under their control until we can get a handle on why these things keep breaking.

Q: What's wrong with them?
The Dreamliner relies on electrical power much more than its predecessor, the 777. Earlier planes used bleed air, which is super-hot, super-pressurized air taken from within the engine, and used it for all kinds of functions, from de-icing to pressurizing the cabin itself. But in order to cut down on energy use, the 787 relies instead on electrical power for that, from some very powerful lithium ion batteries. Those batteries have of late taken up a new hobby: catching on fire and freaking the hell out of all of us.

Q: Wait a second, lithium ion batteries? Like in hybrid/electric cars? And phones and laptops and a million other things?
A: Well, kinda. There are different kinds of lithium ion batteries, using different chemicals and different reactions, and they behave pretty differently. This is a great explanation of what's going on in those batteries, but in short, the Dreamliner uses cobalt oxide batteries, the same kind as what's used in smartphones, laptops, and tablets. It's chosen for all of those purposes because it's got a crazy-high energy content for its size and weight--like, twice that of the batteries used in electric cars--but it also has one very big problem. That would be heat.

Gadget makers have worked for years on cooling methods so their batteries don't catch on fire, and sometimes they do anyway, but these batteries are pretty small and not all that hazardous. The batteries in a Dreamliner, on the other hand, are huge. And on fire.

Q: But planes always have problems at first, right? Aren't these just growing pains?
A: Yeah, that's a common thought, helped along by just about every Boeing exec and anyone else who has a financial stake in the Dreamliner not catching on fire repeating it. And it's not false, exactly. But the problems the Dreamliner is having aren't exactly the same kinds of problems as, say, the Boeing 777. The 777 has had eight so-called "aviation occurrences," which is airplane code for "accidents." But those problems were mostly easy to solve--there were a few issues with the de-icing system, which was subsequently redesigned, and all the other issues were one-offs, like a 2011 cockpit fire that was probably due to "a possible electrical fault with a supply hose in the cockpit crew oxygen system."

The Dreamliner has had many more problems. Cockpit windows have cracked several times. At least three of the 50 active Dreamliners have had overheating problems with the lithium ion batteries, leading to smoke and/or fire. Two planes have had fuel leak problems. These are much more difficult to manage than a de-icing flaw; you can't just swap out the batteries, since there are no other batteries with the same size and energy storage, and as the batteries are a much more integral part of the plane's entire operation, this isn't a small issue. The fact that the Dreamliners have had similar problems is a cause for concern.

Q: How long was this thing in development? How did this slip by?
A: Ah, good question. The Dreamliner has had a very long and tumultuous birthing process, with several redesigns over the years. The Dreamliner is actually several years behind schedule on many of its deliveries; you'd think in that time someone would make sure the thing didn't catch on fire. But nobody really knows how this kind of thing got by; best guess is that with such a new kind of electrical power system, nobody really knew how the Dreamliner would respond with repeated use. On the other hand, Qatar Airlines CEO Akbar Al Baker, among other "airline insiders," has said he's not surprised by the groundings.

Q: What happens now?
A: The FAA and the equivalents in other countries will conduct full-scale investigations into the problems with the Dreamliners. We won't know what the solutions are until we see those findings. So the answer to the sub-question here, "can the battery situation be fixed and how," is "it can probably be fixed, but until we know precisely what the problem is we won't know how." In the meantime, some of the airlines are demanding payment, considering they just spent millions of dollars on a plane they can't fly, and it's possible that others will decide not to continue with their purchases. Boeing has about 800 Dreamliners set to be built; if people start pulling out, the company is going to be in serious trouble.

In the past few years, scientists have linked an oil-and-gas industry practice, called wastewater injection, to increased earthquakes in normally quiet places like Oklahoma and Texas. Now, a new study says wastewater injection could make American Midwest faults more vulnerable even to major seismic activity halfway around the world.

The study linked three major earthquakes outside the U.S. to mid-size shakers near injection sites in Oklahoma, Texas and Colorado. Here's one example: The study found that the enormous earthquake that devastated eastern Japan in March 2011 triggered a swarm of quakes-the largest was magnitude 4.3-near Snyder, Texas. The study also found a distant trigger for the Prague, Oklahoma, quakes that we've covered before.

Now, causes and effects are pretty important here, so let's go everything step by step.

• Scientists already know that wastewater injection occasionally triggers small local quakes. That doesn't mean that all wastewater injection triggers quakes. Most of the U.S.' 30,000-some wastewater injection wells never experience earthquakes. However, some do.
• Wastewater injection has increased in the U.S. in recent decades because it's a comparatively quick, cheap way to dispose of waste fluids from oil and gas drilling. Since companies began doing it more often, U.S. Geological Survey and other scientists have noticed more earthquakes occurring in the Midwest, which isn't normally so seismically active. Three different geologists told me this, unprompted, when I was researching the Prague quakes earlier this year.

  Not all Midwest quakes are necessarily related to human activity, as the area does have faults and has hosted natural earthquakes in the past. However, the uptick does seem to be injection-related.

• Earthquakes of magnitude 8.0 and higher send big shockwaves all over Earth. In the past, scientists have concluded that such major quakes are able to trigger distant, naturally weak faults. Now, a team of geologists from Columbia University and the University of Oklahoma have determined that the same thing can also happen to faults that people have artificially weakened through drilling activities.
• Injection-triggered earthquakes are usually small, magnitude 1 or 2, and barely perceptible to townsfolk nearby. When Prague, Oklahoma, was hit by two earthquakes of magnitude 5.0 and higher in 2011, researchers debated whether those quakes were injection-triggered. A peer-reviewed study said they were; the Oklahoma Geological Survey, which hasn't yet published their conclusions formally, said they weren't.

  This latest study finds some evidence that those severer quakes may be injection-triggered. At least half of the magnitude 5.4 and higher earthquakes in the Midwest occurred near wastewater injection wells, the Columbia-Oklahoma team found by analyzing earthquake records

This and similar studies could help scientists better predict when and where human activity-triggered earthquakes will occur. In the examples the Columbia and University of Oklahoma researchers analyzed, a big, overseas earthquake preceded a swarm of small quakes around certain wastewater injection sites. Then, months later, a larger quake would hit where the swarm occurred. A swarm could serve as a warning and risk factor for a large quake later, Nicholas Van der Elst, a seismologist at Columbia who worked on the new study, told Nature.

At the same time, there's more to learn. Quakes also occur near injection sites without a warning swarm, Nature reports.

The new study appeared yesterday in the journal Science, which also published two other studies on human activity that triggers earthquakes. One study looked at earthquakes triggered by a geothermal project in southern California. Another reviewed previous studies of waterwater injection and fracking-related quakes.

Inspired by a Reddit post suggesting food products carry QR codes that would allow a microwave to automatically follow cooking instructions specific to that food, developer Nathan Broadbent decided he could hack a better microwave, one that could download and carry out different instructions on power levels, cook times and stirring intervals.

Using Raspberry Pi, a compact single-board computer, he programmed his microwave to respond to voice commands and iPad controls, and even more conveniently, to instructions pulled from a quick barcode scan. He gave it a new touchpad, new sounds, an automatic-updating clock and a web page that allows him to control it using his phone.

There weren't any online databases out there that contained instructions the microwave could pull to know how to cook, for example, a Jimmy Dean sausage, egg and cheese croissant--so Broadbent created one.

And since he went to the trouble to program his microwave to do all these fun things with Raspberry Pi, of course he had to use it to make raspberry pie.

Broadbent details his full process over on his blog, if you're interested in giving it a whirl. Or you could just buy barcode scanning microwave. But it wouldn't be able to tweet for you like this one--and everyone knows if you didn't tweet it, you didn't eat it.

The pufferfish is a very curious animal for lots of reasons; it swallows air or water to make itself larger and more threatening, it combines its combining pectoral, dorsal, anal, and caudal fins into one set of fins (like a seahorse), and it is often super poisonous. But Dr. Gareth Fraser of Sheffield University is focused on the puffer for a different reason: its teeth.

The puffer, like lots of bony fish (meaning, not cartilaginous), constantly regrows its teeth. The puffer doesn't have delineated teeth like most other fish, though; instead, after its first set of teeth have fallen out (like human baby teeth), it grows a solid structure that looks like a beak. This beak is made of horizontally growing layers of dentite, the usual tooth material for fish, but appears as a single band.

Fraser managed to map the specific cells responsible for the constant regrowing of teeth in the puffer. That's of great interest to us, because humans, unlike lots of other animals, only grow two sets of teeth. Your baby teeth fall out, then you grow your adult teeth, and then...that's it. That's all you get. And that's less than ideal, as most any professional hockey player can tell you (through gaps in their teeth).

Interestingly, Dr. Fraser thinks humans may evolve, in millions of years, the ability to regrow teeth past that second set. "With our extended lives and modern diets, the limited supply of human teeth is really no longer fit for purpose," he said. By figuring out exactly how fish regrow teeth, he may be able to accelerate that process of evolution.

So play hockey without fear! A fix for your broken grill may be in the works.

[via University of Sheffield]

Can I get this job? Researchers have discovered a new species of wild mountain strawberry. It grows in the Cascade Mountains of Oregon, at elevations of 3,000 feet to about 5,000 feet.

The U.S. Department of Agriculture has already squirreled away a sample of the strawberry in its plant bank in Corvallis, Oregon. The U.S. agency manages the bank as a repository of genetic diversity for edible plants.

At first blush, the new strawberry looks much like other wild strawberries that grow throughout Washington, Oregon and California, says Kim Hummer, the USDA biologist who discovered the berry. Genetically, however, it's quite different. It has 10 sets of chromosomes, unlike other wild strawberries in the area, which have only eight. In fact, the only other 10-chromosome wild strawberry that scientists have identified grows on one Russian island northwest of Hokkaido, Japan. Grocery store strawberries have eight sets of chromosomes.

Having more chromosomes often make fruits bigger, but the new berry, which Hummer named Fragaria cascadensis, is small.

Other subtle differences set the "Cascade strawberry" apart. It has tiny hairs on the upper surface of its leaves and has comma-shaped, instead of teardrop-shaped, seeds on its surface. (Scientists actually consider each of those "seeds" a separate fruit. They're called achenes.)

Want to see and taste the new fruit for yourself? Hikers may find the berry growing on the western, wetter side of the Cascade Mountains, off the Pacific Crest Trail, Hummer tells Popular Science. It grows only in Oregon. Hummer suggests rubbing the leaves to feel if there are those telltale hairs. Some may be able to spot the hairs and the seed shape, although Hummer suggests a pocket magnifying glass for those with "older eyes."

The berries, which ripen in August, are edible. Hummer doesn't make them sound particularly tasty, however. "Flavor-wise, it had a sugar-acid mix. It has a white interior. It's soft," she says. "It would take a lot of developing to make a commercially viable fruit out of it."

The alien landscape above is actually a slice of Appalachia in Pennsylvania. At the center of it, in bright reds and vibrant purples, sits Raystown Lake.

Raystown is an odd lake - it's man-made, and man-made twice, first in the 1910s for an electrical company, and then a second time in the 1970s by the Army Corps of Engineers for better flood control and more hydroelectric power.

The picture comes from the Europe Space Agency Envisat satellite. Launched in 2002, it was designed to take measurements on the ocean, atmosphere, land, and ice. It performed this mission until contact was lost in April, 2012. The image above is a composition of three images snapped between December 2007 and May 2008 with Envisat's Advanced Synthetic Aperture Radar. Neat!

[Observing the Earth]

63 light-years: the distance from Earth to the blue exoplanet HD 189773b, which looks like a cozy place to live-except its surface temperature is 1,000 degrees Celsius and it rains glass. Sideways.

5.5 million square feet: the floor space of the new world's largest building, which could fit 20 Sydney Opera Houses inside it and has its own artificial sun

1980: the year the American Helicopter Society offered $250,000 to anyone who could build and fly a human-powered aircraft for longer than a minute. After 33 years, a team has finally claimed the prize!

23 million years: the age of this whole lizard preserved in amber, just discovered in Chiapas, Mexico

260 feet by 260 feet: the size of 3-D printer needed to print a private jet

100 percent: the accuracy with which this electronic pee sniffer detected bladder cancer in a recent test

$600: the price of this eco-friendly urinal-sink hybrid

45 percent: the amount by which this smog-eating pavement coating reduced air pollution around a neighborhood in the Netherlands during days with low humidity and high radiation

10 minutes: the time it takes to turn a match into a tiny rocket

2020: the year set for NASA's next Mars rover mission, which will hunt for signs of ancient life

Even though listening to sad songs should leave us feeling terrible, we have a tendency to actually kind of like them. Case in point: A 2008 study found that minor-key music sounded sadder than major-key music to people, but that people found it more likable.

Well, a group of Japanese researchers just got paid to figure out why we enjoy crying it out with Adele over her broken heart so much. It's not just masochism--although we understand that the song is supposed to evoke sadness, we end up feeling more positive or ambivalent emotions in response.

In a study of 44 people, participants listened to one of three lesser-known classical pieces--to avoid emotional influence from memories connected to hearing the piece before--in both a major and minor key. Researchers asked them to pinpoint the feelings they experienced while listening to the music, as well as predict what kind of emotions they perceived other people would experience while listening to the song.

Participants perceived the sad music (the songs in a minor key) as tragic, but it didn't make them as miserable as they thought another person would feel, the researchers write:

Part of the reason for this could be that we expect to feel sad, and are thus pleased when our expectations come to pass, a phenomenon called "sweet anticipation."

"Even if listeners experience negative emotions when listening to sad music, sweet anticipation might still allow them to feel positive emotions," the paper concludes. "Even if the music itself is perceived as negative, and negative emotion is aroused in listeners in part, we have a tendency to experience ambivalent emotions by concurrently feeling pleased by virtue of our cognitive appraisal."

It could also have to do with the fact that the sadness we feel isn't the direct result of a sad situation. Listening to someone else sing about his or her sadness is a vicarious experience, so the sadness we feel isn't as threatening to our well-being. We can just sit back and enjoy someone else's heartbreak.

The study is published in Frontiers In Emotion Science.

Sometimes the conveniences of the future are small, but still awesome. The staff at Thingiverse has created a program to turn any sketch into a digital file for a cookie cutter that's ready for 3-D printing.

You can even make a cookie design with cutouts inside-for example, I could make a star-shaped cookie with a hollow "F" in the middle-and the program will automatically add the scaffolding necessary to make it happen.

The program appears on Thingiverse, which is a website where users share the digital designs they've made for 3-D printers.

While you're waiting for your custom cutter to print, why not learn a bit about the chemistry of cookie baking?