Tiny Autonomous 'Copters Combine Voltron-Style To Create a Larger, Stronger Aircraft

Two rotors are better than one, and if our recent excitement over UPenn’s quadcopter is any indication, four rotors is better than two. Sometimes. Researchers at the ETH Zurich recognize that different tasks call for different aircraft, and with that in mind they’ve designed the Distributed Flight Array, a flying platform consisting of multiple small autonomous single rotor aircraft that can dock with one another to create a larger, more powerful aircraft.

The DFA, developed by ETH Zurich’s Institute for Dynamics Systems and Control, consists of multiple fixed propellor aircraft, each with its own sensors and flight control system. Individually, the components fly somewhat erratically, but joined together they become a larger sensor-based flight platform, capable of maintaining level flight by rapidly sharing data between them. When docked together, if something disturbs the array’s level flight each individual rotor can compensate appropriately to bring the system back into balance.

http://www.youtube.com/watch?v=7iHZKMDvdNI&feature=player_embedded

While the current DFA is a proof of concept, such a scheme could have a variety of applications, not least of which is the relatively straightforward yet sometimes difficult task of picking stuff up. Since the DFA is modular, users could deploy enough lift to execute a task without wasting resources on overkill. Further, its modular nature allows for some degree of failure within the system. If one or two of the bots fail, the others could compensate and even reconfigure to allow fresh bots to swap into the places of those that aren’t working.

Swapping components mid-flight might seem like tricky business, but considering how far researchers are coming along with these kinds of autonomous vehicles it’s certainly feasible. Just check out the video below, also from ETH’s Institute for Dynamics Systems and Control. These two quadcopters don’t just hover with precision. Their movements are so well choreographed, they actually dance with each other. No, seriously.

 

http://www.youtube.com/watch?v=NPvGxIBt3Hs&feature=player_embedded

Four-Ton Transformer Tribute to Ancient Chinese General Meshes History and Sci-Fi

In the U.S., we often complete the run-up to graduation by writing 25 pages of extremely dry thesis that is typically read and appraised by a single person before being relegated to the library stacks forever. Bi Heng, a student at the Central Academy of Fine Arts in China, decided that instead he would create a 4-ton, $43,000 Transformer-inspired sculpture honoring legendary Chinese general Guan Yu.

The sculpture was assembled from components of an old Jiefang brand vehicle, a 25-year-old military service truck employed by the People’s Liberation Army. Robo Guan Yu stands about 32 feet tall and wields a dynastic-era weapon that makes for a nice juxtaposition with the post-Revolutionary scrap he’s assembled from.

As for the real Guan Yu, he was a respected general at the end of the Eastern Han Dynasty and a key player in the civil war that ended it. Though his military exploits and valor have been pumped up to mythical standards over the years, he was apparently legitimately revered for his prowess at kungfu. Though Robo Guan Yu is unfortunately static, check out the accompanying promo video below to see the general’s latest moves.

 

http://news.mmosite.com/content/2010-06-07/the_coolest_graduation_piece_ever_a_guan_yu_transformer.shtml

Stem-Cell Tourism: Adventures at the Fringes of Experimental Medicine

Droves of patients are heading overseas for stem-cell therapies unavailable in the U.S. Is it a dangerous scam or is America just behind the curve?

It’s 2:30 in the afternoon in the Dominican Republic, and Karen Velline, a 66-year-old grandmother from Cold Spring, Minnesota, is lying on an operating table, swaddled in sterile surgical sheets. She’s just moments away from a procedure so experimental that no doctor will perform it on U.S. soil. Yet she calmly stares up at the ceiling, more excited than anxious. Despite the controversy surrounding it, Velline believes that this procedure—which she has paid Regenocyte Therapeutic, a stem-cell company in Bonita Springs, Florida, $64,000 in cash to perform—could save her from a debilitating lung condition. After months of anticipation and planning, she’s ready for things to get under way.

Cardiologist Hector Rosario nods to his team and begins inserting a clear, narrow tube into a vein in Velline’s leg, slowly threading it all the way up to the right side of her heart. “That’s the catheter,” whispers medical supervisor Leonel Liriano, who has agreed to let me watch the surgery. I can see the tube moving on an x-ray imaging screen, inching closer to its final destination, the branched pulmonary arteries that supply blood to her lungs. With the catheter in place, Rosario reaches for a syringe filled with a solution of Velline’s own stem cells: the $64,000 potion. He inserts it into the catheter and depresses the plunger. A subsequent injection of saline serves as a chaser, ensuring that the cells migrate all the way to the lung vessels.

If the technique works as advertised, the cells—hand-couriered on a plane from Israel, where they were mixed with platelet growth factor to make them multiply, and delivered minutes ago to the operating room—will grow into the delicate gas-exchange regions of the lungs. Over several months, they should regenerate failing tissues that have been ravaged by Velline’s hypersensitivity pneumonitis, a degenerative lung disease caused by an allergic reaction to dust and chemicals that has left her dependent on three liters of oxygen a day. Doctors at the Mayo Clinic in Minnesota told her that the only hope of reversing her condition was a lung transplant, a high-risk procedure with a drawn-out recovery period. “That was something I didn’t want to consider,” she says.

Regenocyte presented an enticing alternative. Its glossy brochures and the effusive patient testimonials on its Web site offered hope that stem-cell therapy could not only keep her condition from getting worse but return her to her old self. If regenerative stem cells could help others, Velline reasoned, why couldn’t they help her too? As far as she was concerned, waiting years for the government to put its official seal of approval on the procedure wasn’t an option. She was dying.

Every year, hundreds of desperately ill Americans like Velline are making similar decisions, sidestepping government regulations and heading overseas to access a smorgasbord of stem-cell therapies unavailable in the U.S. Many of these treatments—offered by companies like Regenocyte, Germany’s XCell-Center and China’s Beike Biotechnology—involve autologous adult stem cells, meaning stem cells harvested from your own blood or bone marrow. These are thought to be safer than stem cells drawn from other donors or harvested from embryos, because they incur fewer risks of rejection or tumor formation. Just how safe, though, no one knows precisely, which is why the U.S. Food and Drug Administration insists on stringent regulations.

What's Truly New in iPhone 4

Apple, through powers of both good and evil, always finds a way to captivate like no other with their new product launches. But in unveiling the iPhone 4 today, they had an unfamiliar challenge to deal with: a world that has already seen in great detail the new product they were about to announce. So this time around, Apple had something more to prove: what exactly about the new iPhone 4 is new today?

Screen


We knew the next iPhone would have a higher-resolution screen, but the specifics are in, and they're pretty impressive. 960-by-640 pixels crammed into the same 3.5-inch screen of the 3GS. They're calling it the "Retina Display," and claiming it's the highest resolution screen ever in a phone (it bests the HTC Evo 4G's ginormous 800-by-480, 4.3-inch screen in both resolution and pixel density). Apple is clearly looking to recreate the "wow" factor of the iPad's high-res, color-rich screen by bringing 78 percent of the iPad's total pixel count to a screen less than half its size. Jobs claimed on stage that the human eye, from 10 to 12 inches away, can discern detail in a screen at up to 300 pixels per inch. And the iPhone 4's screen has 326 ppi, which means sharper text and UI elements all around (which will be natively up-res'd to some extent in existing apps).



Onboard Gyroscopes

Engineers have made great strides lately in making gyroscopes smaller, cheaper and more efficient, and they're clearly part of the next-generation in mobile motion-capturing sensors. The power of ubiquitous, low-cost accelerometers was introduced to the masses in Nintendo's Wiimotes, and since then they've trickled on down to just about every smartphone or mobile gadget on the market. And just as Nintendo achieved greater motion accuracy for their Wiimotes with the gyroscopic Motion Plus attachment, which pairs both sensors' inputs into true 1:1 motion capture, Apple is adding a 3-axis gyroscope to the iPhone for the same enhancement--another claimed first for a mobile phone.



Gyroscopes add fine-tuned rotational detection to accelerometers' ability to detect linear motion, so you can expect much greater accuracy from tilt-controlled games and other apps. Steve Jobs demonstrated a Jenga-like game for the iPhone on stage, and all I can say to that is yes.

HD Video Editing with iMovie


Several smartphones on the market now can capture the same 720p, 30fps video added to the new iPhone 4, but in addition, Apple demoed an impressive mobile version of iMovie that brings insanely powerful-looking onboard editing, rendering and export to your phone. Other phones can edit video too, sure, but what Apple showed today seems to go well beyond what's currently offered. If it works as advertised (and that's a big if, considering that I find the current desktop version of iMovie the most frustrating piece of software on my Mac), this is a huge leap forward.

Engineering


Apple loves their engineering wizardry, and with the iPhone 4, those strange gaps in the side of the frame that to many seemed unfinished have been revealed as something a bit more interesting: the stainless steel rim of the phone does double duty as a multi-purpose antenna for the phone's wide range of radio communications. It's crazy to think of how much transmission takes place, with GPS, Wi-Fi, Bluetooth, 3G data and cellular voice all having their own communications bands. Apple didn't hype any monumental gain in reception, but they did cite the antenna as the key to freeing up more room for a bigger battery that adds 40 percent more talk time.

Video Calling


Apple is promoting the iPhone 4's video calling, dubbed FaceTime, as a paradigm-shift in human communication. Maybe you've heard that before describing various video-calling products over the last decade, at least? So I'm not buying the brain-melting power of a video call on my iPhone just yet. What's interesting, though, is Jobs's announcement of FaceTime as an open standard. Details are vague at the moment, but if FaceTime became a de facto option for video calling on a host of different devices with webcams (and "just works" as so many Apple products claim to do), that could be an interesting development.



Also, for now, you're limited video chatting in a place with Wi-Fi, as the demand on AT&T's network would be extreme.

The Inside Story of the MotoCzysz E1pc, the World's Most Advanced Electric Motorcycle

This is the 2010 MotoCzysz E1pc, a race bike built by a tiny Oregonian company focused on pushing the limits of electric performance to the absolute max. It packs 10 times the battery capacity of a Toyota Prius and 2.5 times the torque of a Ducati 1198 into a package that looks like something out of a 24th-century Thunderdome.

Tomorrow it will race in the Isle of Man TT, the toughest motorcycle race in the world. The technology at work is so advanced, so unprecedented, that we may be looking not just at the future of motorcycles, but of all electric vehicles.

The reason the all-electric race bike is here, 4,600 miles from its home in Portland, Oregon, is to prove itself. Ever since 1907, the Isle of Man TT has been the race for bike manufacturers and riders to show their mettle to the public. The thinking goes that if you can lap its 37.7 miles of tiny, twisty back roads with an average speed in excess of 100 MPH, you or your bike become indisputably proven. Well over 200 riders and a handful of spectator’s have been killed trying to do just that.

But as recently as two days ago, the future of motorcycles was missing its body panels (stuck in customs). Before this week, the finished bike has never even seen the light of day. But even in its unproven, incomplete state, it's been putting in laps that have the competition quaking in their leather.

The customs snafu (and the mad dash to even finish the bike in time for the race) is not the first time Michael Czysz, MotoCzysz’s founder, CEO and the driving force behind the E1pc, had suffered a set back on this tiny rock in the middle of the Irish Sea. Last year, the Isle of Man TT hosted the first ever all-electric motorcycle road race, and MotoCzysz was there with the E1pc's predecessor. But while the machines that entered were technically impressive, their performance wasn’t. The race-winning team only averaged 87 MPH, well short of the 100 MPH watershed that defines a serious lap and way behind the 131.5 MPH lap record set by the fastest gas-powered superbikes. MotoCzysz didn’t even complete a full lap, suffering an electric spike from their experimental kinetic energy recovery system that fried the bike’s electronic control unit (ECU).

That was a major blow for Czysz (pronounced "sizz"). Five months of whirlwind effort from the former motorcycle racer and architect and his small team in Portland saw them abruptly transition away from developing a 200 HP, gasoline-powered MotoGP bike to produce an electric bike that blew the zero emissions competition away standing still. The E1pc looks like an X-Wing crossed with an iPod to the other electric racer’s cobbled-together adaptations of existing internal combustion engine bikes.

 

“We overreached and it bit us in the ass,” says Czysz of last year’s race. “We’re trying to do too much with too little, we’re effectively building a Formula One level machine with one engineer, two machinists, one CAD guy, me and a body dude.”

But the E1pc was out in front when it broke down. Way out front.

Remake, Remodel

This year’s all-new 2010 E1pc is too--out front, that is, not broken down. During practice this week, it reached a top speed of 140 MPH—besting its closest electric competitor’s 102 MPH. The E1pc also clocked a 94.6 MPH lap, tantalizingly close to the 100 MPH goal. Yes, it completed that lap. But that’s not the amazing thing; the E1pc ran that time while using, on average, less than 40 percent of its throttle and crossed the finish line, according to Czysz, with “plenty in reserve.”

 

But this new bike is way more than just an ECU that doesn’t blow and a bit more battery capacity. It’s a ground-up redesign of 2009’s largely off-the-shelf approach. “A bike has a relationship with the rider and a balance that is way beyond cars and computers, so you can’t just randomly shove stuff around and hope it works,” describes Czysz. “You have to work around the batteries, they’re they largest component, the heaviest component and the most important component.”

On the 2010 E1pc the batteries are huge, visually dominating the bike and occupying the space traditionally reserved for an internal combustion engine. There are 10 individual lithium polymer cells that each weigh 19.5 Lbs and were hand-assembled by a company that typically builds batteries for NASA. The level of integration here hints at the kind of work that’s gone into the rest of the bike. There are no wires connecting the batteries to the bike or any exposed terminals. Instead, posts on the batteries lock into receivers on the bike’s frame, at once making the electrical connection and supporting the batteries’ weight. The proprietary internal arrangement is secret, so we can’t show you a picture of it, but it allows the batteries to be swapped out in just a couple of seconds.

That ability is crucial. The electric motor is powerful enough to chew through the 12.5 kWh of on-board power in just 40 miles under race conditions (in comparison, the 2010 Toyota Prius's battery pack holds just 1.3 kWh and can travel only a single mile in full-electric mode). Quick-swap batteries allow the team to run road tests without waiting four hours between charges and, more importantly, removable batteries bring huge safety benefits. The E1pc is running close to the maximum allowable 500 volts, enough power to turn a wrench into molten metal in a flash of white light or split a mechanic’s hand in half (it’s already done the former). The ability to remove that power source from the bike before working on it renders the machine safe from accidental electric shocks. This level of safety and convenience have clear applications in mainstream electric consumer vehicles--don’t expect Czysz’s patents to stay on one-off race bikes.

But the custom-engineered, oil-cooled electric motor that sucks up those batteries’ juice may be the single most important individual component driving the E1pc’s exceptional performance; while most electric bikes repurpose electric motors built for forklifts or high-power drills, Czysz’s motor is the first to be developed from the ground up to win races.

The DC internal permanent magnet motor, which Czysz calls “D1g1tal Dr1ve,” is small enough to hide within the swingarm beneath the rear shock. The oil-cooled motor makes more power and torque than all three air-cooled motors in last year’s E1pc combined, while being smaller than one of them individually. And crucially, it develops its 100 HP and 250 Lb-Ft of torque continuously. Air-cooled electric motors, on the other hand, quote peak figures which they’re only able to reach for a very brief period of time due to the rapid buildup of immense heat. Sometimes, they can only reach peak power for a fraction of a second. The MotoCzysz can always make that 100 HP--as long as the batteries hold out, that is. The oil-cooling is key here, allowing the motor to exponentially shrink in size and weight for its output level; air-cooled motors are huge, so their large metal components can soak up the heat.

 

Despite batteries' limited ability to carry energy on board when compared to internal-combustion bikes, battery and motor together form a near ideal powertrain for racing. Adrian Hawkins, MotoCzysz’s lead engineer who left fabled engine design firm Cosworth to develop the E1pc’s electric drive technology, explains: “With the interncal-combustion engine, you’ve got a long way to go from where that throttle is: through the port, through the piston, through the combustion chamber, through the rod, through the clutch, through the gearbox, through the chain to the rear wheel.” In comparison, the E1pc’s electric motor offers a virtually direct connection between throttle and rear wheel. And for racing, that’s what engineers strive to develop. But power is not as important as control.

“I can pretension the chain with the throttle on that motorcycle,” says Czysz, explaining the implausible level of precision possible. “One percent throttle means one percent torque, it is the perfect drive. But now we have to work around all the other problems that aren’t perfect.”

First among those "other problems" is the constant struggle with a limited energy capacity and therefore limited power. Just as it’s pointless to pair a V12 engine with a two-gallon gas tank, there’s no point in carrying a motor that makes more power than the batteries can dish out. So a major design challenge for the E1pc is to insure it makes the most out of every single Lb-Ft of torque it makes.

“Ninety percent of a vehicle’s power is used simply to move the wind,” says Czysz, pointing out how aerodynamics play an even more important roll on electric vehicles than conventionally-powered ones (exhibit A: the Prius’s odd stub nose and compressed rump). Czysz has radically reduced the frontal area of this year’s bike — eyeballing the two next to each other, 2010 looks a third slimmer than 2009 — but it’s the wind’s exit that’s more important than its entrance.

“The low pressure area behind the bike is extremely vital,” explains Czysz. “That’s how planes work, the air accelerates so fast over the top of the wing that it creates low pressure that sucks the airplane up.”

So the challenge for a motorcycle aerodynamicist is to recombine the airflow behind the bike so it’s not sucked backwards as much as it is to split air cleanly around the front. Czysz also created ducts through the E1pc’s frame that suck air from the high-pressure area at the front through to the area beneath the seat, breaking up the low pressure. Gulfstream-jet-style winglets on the fairing whirl turbulence into these ducts just as the pull air rapidly through the motor and controller-cooling radiators.

The other extreme limiting factor to motorcycle aerodynamics is the big leather sack of human sitting on top, spoiling the airflow. Czysz has addressed this too, with perhaps the defining visual element of the 2010 E1pc. Turning to time trial bicycle racing for inspiration, he created a second riding position that the racer will move into on straights. By sliding their butt off the main seat and onto what's basically a modified pillion pad at the extreme rear, the rider adopts an incredibly low, flat-backed riding position that still gives them the ability to keep their feet on the foot pegs and hands on the handlebars; they can still fully control the bike in this position and even attack high speed corners by weighting the pegs and turning the bars.

All this aerodynamic innovation is reaping rewards on the racetrack. While competitors have adopted all-enclosed 1950s-style dustbin fairings that can negatively impact stability and therefore safety, Czysz is reaching far higher speeds using his modern methods.

The Complete Package

Every one of the E1pc's components — the motor, the controller, the battery packs, the aerodynamics — is all-new and class-leading, but they're not what makes the machine so special, the real trick here has been integrating all those into a whole that actually looks and functions like a motorcycle should; a rider accustomed to a gas bike will feel right at home on the MotoCzysz.

So what’s the ultimate payoff for all this besides a one-off, priceless prototype race bike? MotoCzysz does plan to develop its own range of production electric motorcycles eventually, but right now it’s about proving ideas, inventing technology and laying the groundwork for a future electric motorcycle industry. But don’t be disappointed if you want to get your hands on some of what you see here in the near future--the patents MotoCzysz is creating will probably appear on production machines from other manufacturers very soon. Indian automobile giant Bajaj, which plans to enter the US market in the near future, has partnered with Czysz for that reason. Hawkins’ talk of the perfect relationship between rear wheel and throttle is also revealing. That’s technology that could easily find a home in hybrid cars or applied to Kinetic Energy Recovery Systems that are popping up in race cars with increasing frequency. In fact, there’s a couple of distinctly four-wheeled vehicles hiding under tarpaulins in the MotoCzysz HQ right now. What they are or who they belong to Michael isn’t saying, but you can bet some of what you see here on the E1pc will end up on production vehicles in the very near future.

The 2010 MotoCzysz E1pc will be racing at the Isle of Man tomorrow (check back here for a followup on the results), and will return to America in July, where it will race at California's Laguna Seca in support of the US Grand Prix on the 25th.

Plastic Antibodies Shown to Fight Off Antigens in the Body Just Like the Real Thing

Artificial Antibodies Plastic antibodies like the ones clustered here could fight everything from viral infections to allergens in the bloodstream.

We use plastics to make everything from our computers to our toothbrushes, but a collaboration of researchers from the University of California at Irvine and the University of Shizuoka in Japan has made a big breakthrough by taking plastics to microscopic levels. Using plastic nanoparticles just 1/50,000th the width of a human hair, the team has created plastic antibodies that successfully function in the bloodstream of living animals to identify and fight a variety of antigens.

Antibodies are the proteins in our bodies produced by the immune system to recognize and neutralize foreign threats like infections, allergens, viruses and bacteria. These can include things as annoying but benign as plant pollen and dust to food allergens, bee venom, and other toxins. Our body produces antibodies in decent quantities, but in the case of allergies our immune systems can be unequipped to deal with certain antigens, and in other cases – such as a bad infection – our own natural antigens can simply become overwhelmed.

To counter these immune system shortcomings, the researchers took tiny plastic nanoparticles that had previously shown the ability to mimic natural antibodies. They then used a process known as molecular imprinting to stamp the shape of the antigen melittin, the primary toxin in bee venom, onto the antibody. By imprinting tiny antigen-shaped craters into the individual particles, the plastic antibodies were then finely tuned to attach themselves to those antigens in the blood.

The team then dosed a bunch of laboratory mice with lethal doses of melittin followed by an injection of the artificial antibodies. Those mice that received the antibodies showed a far higher survival rate, suggesting that the finely tuned plastic proteins can indeed track down and destroy threats within the living body.

The success of the molecular imprinting process coupled with the heightened survival rate of the mice suggests researchers could tailor a variety of these nanoparticles for use in just about any case where the body relies on antibodies for to fight off threats. That’s a lot of cases, opening the door to a synthetic immune booster that could potentially be used to treat myriad allergies, illnesses and infections.

Early-Adopting Dolphin Uses iPad Touchscreen to Communicate with Humans

Steve Jobs promised us the iPad would change our lives, and while it hasn’t been all things to all people – what about that front-facing camera, Steve? – the beauty of such a device is that developers (to the extent that Apple will allow them, anyhow) are free to get as creative as they want with the device. Just ask Merlin the bottlenose dolphin. He loves the iPad, and thanks to a symbol-based human-dolphin communication interface being developed for the iPad’s ample touchscreen, he could one day be able to tell you so himself.

The program, being developed by a non-profit called Speak Dolphin at Dolphin Discovery’s swim facility in Puerto Aventuras, Mexico, is being tested on both the iPad and a Panasonic Toughbook. Merlin, a two-year-old bottlenose, uses his rostrum (that’s his elongated beak) to operate the touchscreen, learning to associates symbols with objects.

Researchers think once Merlin gets the hang of using the touchscreen to associate objects, he’ll be able to learn a kind of symbolic language to express more intangible ideas, like actions or even emotions. Of course, this dolphin-human interface requires some other more basic technology beyond the program, like anti-glare screens that Merlin can better see and waterproofing tech that keeps him from ruining his favorite status symbol.

But what’s starting out as rudimentary symbol association on a touchscreen could potentially provide a way for humans to communicate quickly and efficiently, if at a very basic level, with the more intelligent species with which we share the planet. Add “Dog Whisperer” to the list of apps we’d like to see hit the store in coming years.

Nanowires Convert Rat's Heartbeat Into Usable Electricity

Nanowires inside a rat can convert the power of breathing and heartbeats into electricity, according to researchers at the Georgia Institute of Technology. The nano-generator could conceivably lead to nano-scale medical implants and sensors powered by the body.

The same GIT team proved five years ago that zinc oxide nanowires could produce electricity from a running hamster, for instance, or from tapping fingers. The wires produce electricity when under mechanical stress, called the piezoelectric effect. But now, it's been proven to work inside a living animal.

Zhong Lin Wang, a materials science and engineering professor at Georgia Tech, led the team that attached the nano-generator to a rat's diaphragm.

Researchers put a zinc oxide nanowire onto a flexible polymer and encapsulated it into a polymer casing to protect it from bodily fluids, Tech Review reports. When attached to the rat's diaphragm, the animal's breathing stretched the nanowire, and it generated a tiny amount of electricity -- about four pico-amps of current at two millivolts. When it was attached to the rat's heart, the nano-generator produced about 30 pico-amps at about three millivolts.

 

The rat generator operates at the femtowatt scale -- a pico-amp is a million millionth of an amp, so it is a tiny amount of current -- so not very much power. But the technology has potential to power nano-sized devices, Wang says in a paper on the results published in the journal Advanced Materials.

Wang's team is already building on the rat findings, Tech Review reports. The team has a device that integrates hundreds of nanowires into an array, giving an output current of about 100 nano-amps at 1.2 volts. The next step is to connect the higher-powered nano-generator inside an animal, Wang says.

 

New Cassini Findings Show Possible Signs of Methane-Based Life on Titan

Something is consuming hydrogen and organic molecules on Saturn's moon Titan, and the recipe matches astrobiologists' theories about possible methane-based life. Granted, there may be other chemical explanations . it's just that no one knows what they are yet.

New data from the Cassini spacecraft show hydrogen is disappearing near Titan's surface. What's more, scientists have not been able to find acetylene, an organic molecule that should be pretty abundant in the moon's thick atmosphere.

All this fits very nicely with a theory from NASA astrobiologist Chris McKay, who proposed five years ago that microbial life on Titan could breathe hydrogen and eat acetylene, producing methane as a result.

Scientists emphasize that the findings are not proof of life, and there's plenty of work to do before non-biological causes can be ruled out. Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," says Mark Allen of NASA's Jet Propulsion Laboratory in Pasadena, Calif., in a NASA release.

The good news is that even if life is ruled out, the non-biological explanations are still interesting. According to previous studies, hydrogen should be distributed pretty evenly throughout Titan's atmosphere. But it's disappearing at the surface.

"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," says Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored a paper published in the journal Icarus.

It's possible that the hydrogen is combining with carbon on Titan's surface to produce methane. But Titan is too cold for that to happen quickly enough to account for all the missing hydrogen. An unknown mineral could be the culprit, meaning scientists may have found a new substance previously unknown to exist on Titan.

The explanations for the dearth of acetylene are equally puzzling. The hydrocarbon should form abundantly in icy aerosols in Titan's atmosphere, but it's not there. It's possible that sunlight or cosmic rays are transforming the acetylene into more complex molecules that would fall to the ground with no acetylene signature, according to NASA.

It's also possible that chemical reactions are transforming acetylene into benzene (which Cassini did observe on Titan's surface), but that would require a catalyst, which hasn't been identified.

There's one more thing: Cassini observed an organic compound with the benzene that scientists have not been able to identify.

Cassini has several more Titan flybys in which to gather data in fact, the craft is set to fly within 2,000 miles of Titan's surface this afternoon, to make infrared scans of the moon's north polar region. The region includes Kraken Mare, the largest lake on Titan, which covers a greater area than the Caspian Sea on Earth. If methane-based microbes do live on Titan, there's a good chance they would live in just those sort of lakes.