Saturn, Backlit By The Sun

NASA/JPL-Caltech/Space Science Institute

Today is the 10th anniversary of the spacecraft Cassini's arrival in Saturn's system of rings and moons. But to make that 2.2-billion-mile journey from Earth, Cassini had to launch on October 15, 1997. So really it's been 17 great years. The International Space Station and the Mars rovers Spirit and Opportunity all launched after Cassini did. Yet Cassini is still in working order, and still sends data and—our favorite—images back to Earth.

Data from Cassini have taught astronomers that several of Saturn's moons have chemistry that is amenable to life. That's expanded science's understanding of where life could thrive in the solar system. Cassini's instruments have also revealed more about Saturn itself, snapping images of its enormous hurricanes and sampling the composition of its rings. Just a few months ago, astronomers used Cassini data to build more evidence that the Saturnian moon Enceladus likely has a subterranean sea.

In honor of Cassini's years of work in space, Popular Science has collected here some of our favorite Cassini-made images. In 2004, just before spacecraft reached Saturn, Popular Scienceinterviewed Candice Hansen-Koharcheck, then with NASA's Jet Propulsion Laboratory, about the mission. She said, "These pictures are probably going to knock people's socks off." She was right. Click below to take a look.

Charcoal is mostly made up of carbon, but also contains hydrogen and oxygen. When it burns it yields carbon dioxide. 

I never thought anybody took the phrase "chemical-free" seriously, because, obviously everything contains chemicals. But it has become a marketing slogan that a lot of people apparently subscribe to, and indeed some of the top Google search results, for example this site authored by a PhD, no less, pursue this angle without strenuously qualifying that the term is meaningless. 

But wait! Now a study has been done on all of the chemical-free products out there. If you like, check out the exhaustive manuscript over at Nature Chemistry. Here's the summary: 

(SPOILER WARNING) If you don't have all of the 0 seconds required to read the list of products that are truly chemical-free, I'll ruin it for you: there aren't any. 

A funny (fake) study, to be sure; the term "chemical-free" is irritating and blatantly wrong. However, there is an argument to be made for expanded testing of industrial chemicals that have been introduced into humans' lives in increasing quantities in the past few centuries. The phrase "chemical-free," in encouraging uninformed chemophobia, detracts from that more nuanced line of thought, and doesn't help anybody. 

Porsche 918

Courtesy Porsche

The pitch for hybrid sports cars has been clear for some time; battery power delivers an instant jolt of acceleration—the 918, for instance, hits 60 mph in 2.5 seconds. But the 918 stands apart in its ability to fully recharge cells while driving. (Typical plug-in hybrids get only a trickle of power while the car’s in motion and need to be plugged in once depleted.) When the 918’s battery is spent, the car’s brakes and engine act as generators, recharging the cells in a matter of minutes and readying the car for another electric boost. The unique powertrain portends a future in which performance will be tied to the efficiency of a battery, not the power of an engine.

2015 Porsche 918 Spyder

Engine: 4.6-liter V8 and two electric motors

Horsepower: 887 (combined output)

Fuel economy: 22 mpg (gas only), 67 mpg-e (electric only)

Price:$845,000

Other Car News You Should Care About

1) Men really do drool over hot cars, at least when women are involved. A study at Northwestern University found that men who were shown pictures of attractive women followed by images of sports cars salivated more.

2) Too much carbon-dioxide can cause drowsiness, so engineers at Hyundai placed a CO₂ sensor in the 2015 Genesis. When the level of CO₂ exceeds 2,000 parts per million, the sensor triggers an infusion of fresh air into the cabin.

3) A study funded by the U.S. Department of Energy has shown that the production of biofuels from corn waste, such as stalks, releases 7 percent more greenhouse gases than gasoline emissions—too high for it to qualify as a renewable fuel source.

4) A new feature in the 2015 GMC Canyon will make it safer for children to ride in the jump seat of midsize pickups. Parents can use the headrest from the rear passenger side to extend the seat cushion and better secure a car seat.

This article originally appeared in the July 2014 issue of Popular Science.

Supercooled Rat Liver

Sitting in its own little pump system

Wally Reeves, Korkut Uygun, Martin Yarmush, Harvard University

To keep a handful of rat livers super-fresh, researchers kept them supercool—that is, stored at temperatures below the freezing point of water.

The procedure was part of an experimental new method for treating donated organs. The method is still in its early stages of development, but it's showing some promise. Rat livers treated in this new way lasted three times as long in storage as rat livers treated in the way that's currently the gold standard for human transplants, which involves a special liquid bath and cooling to cold but not supercold temperatures. Before even thinking about testing the method in humans, researchers will have to see if it works in lab animals that are larger than rats—bigger livers are harder to cool safely.

The research is part of an ongoing effort to extend the time doctors are able to store donated organs. Longer storage times means more wiggle room for doctors. Say someone who lives in Asia needs a liver transplant. If storage times were long enough, the Asian patient could get a North American liver, should no compatible livers be available closer by. Right now, doctors are able to store donated livers for up to 12 hours before they really need to transplant them into a person.

Of course, keeping things extra-cool is an obvious way to store living tissues for longer. That's the whole idea behind cryopreservation, right? At temperatures below freezing, however, there's always the danger that water in the tissues will form ice, which is damaging. The cooling-and-rewarming process can also irreversibly damage cells in biological tissue. So, for the new method, a team of researchers from the U.S. and the Netherlands bathed their rat livers in a liquid containing two non-toxic anti-freeze molecules. They also used a special machine that helped circulate the liquid through the livers before cooling them and before transplanting them. The circulating anti-freeze kept the livers safe even as they were brought down to -6 degrees Celsius.

The researchers found that they were able to store their rat livers for three days, then transplant them into healthy rats. All six rats who received those three-day-old livers survived the entire duration of the study, which lasted three months. An additional 12 rats received supercooled livers that had been stored for four days. Seven of those little guys survived for three months. On the other hand, all of the rats died whose liver transplants had been treated in the usual way, but stored for three days—much longer than the 24 hours that researchers have previously found is tops for rat liver transplants.

The American-Dutch team published its work online yesterday in the journal Nature Medicine. 

Snowy fisher

www.ForestWander.com / Wikimedia commons

Earlier this month, a fisher was photographed in the Bronx, the first spotting of this weasel-like animal in New York City in modern times. This is in keeping with a general trend: After being exterminated from much of their native habitat throughout the Northeast, they are slowly spreading back into their old stomping grounds and have increased their geographic range more than two-fold in the last century, according to a study in Animal Conservation. The animals, "somewhere between a domesticated ferret and a wolverine" in size and attitude, are also getting bigger, the study noted.

"Finding that fishers are evolving a larger body size and that they're eating larger prey really shows that they're starting to move into the larger predator space," Roland Kays, a researcher at the North Carolina Museum of Natural Sciences and a professor at North Carolina State University, told National Geographic.

As Kays wrote of wrote of the Bronx fisher, in a post at the museum's blog:

Interesting indeed. The animals are quite good at crawling through small holes, which makes them good ratters. It also helps them to hide in holes and/or sewers at night, and to move about through culverts and avoid "becoming roadkill," Kays wrote. 

These aniamls are a type of mesopredator, or "middle predator," meaning they prey on middle-sized and smaller animals--and males can grow up to four feet long and weigh 13 pounds. Their spread is a type of "mesopredator release," which happens due to a reduction in the number of apex, or top-level, predators like wolves, the study authors wrote. (In other words, the absence of top-level predators has allowed fishers to be "released" from this predation pressure.) 

A fisher in the Bronx

NYPD officer Derek Lenart took this photo at dawn on April 15, of a fisher running along a sidewalk in the Bronx.

North Carolina: Museum of Natural Sciences / YouTube

[National Geographic]

If we’re lucky enough to survive Armageddon, our precious electrical grids won’t. But we needn’t pine for energy as we build a new civilization from the scraps of the old one. Inside every abandoned car is a lead-acid battery just waiting to power a makeshift arc welder. 

Saws, drills, grinders, and lathes may be more precise tools, but welding devices are unmatched for their versatility and brawn. Arc welders work by melting steel with a blinding electrical discharge. They can both sever thick beams and fuse pieces of metal together in ways that other tools can’t. Amid their showers of sparks, a pile of scrap can become a house or a boat—or even an arena for postapocalyptic blood sport.

A single car battery lacks the juice to sustain a metal-melting arc between the tip of a welding rod and a piece of steel. (Zombies holding your supply hostage? Welding rods can be made from coat hangers, silica gel, lye, and paper.) So to build my welder, I wired three car batteries in series, then clamped a set of jumper cables between the negative lead of the first battery and a chunk of steel. With another set of cables, I linked the last battery’s positive lead to a welding rod.

By scraping the rod against the steel, I was able to strike an electric arc. The batteries provided a flow of electrons powerful enough to melt steel in the rod and base metal and merge them, creating a weld. My rig has a maximum output of 300 amps, which is plenty to cut or combine thick steel. Yet it is adjustable, so it can also weld delicate sheet metal; I routed the batteries’ current through a dining fork, which provides some resistance and limits the flow of electrons.

If you can make a welder and get good at using it, you’ll have an unstoppable tool for building after the end-time. When you run out of electricity, charge the car batteries with a bike generator [see “Rebuild,” March 2014] and get to work assembling your very own Thunderdome.  

Warning: Do not attempt until lawyers no longer roam the Earth.

Hackett is Popular Science’s intrepid DIY ​columnist.

Photograph by Ray Lego

This article originally appeared in the July 2014 issue of Popular Science.

Diagram Of A Drone System

This diagram shows the drone, the communications relay, the remote pilot, and the air traffic controller.

Office of the Inspector General, U.S. Department of Transportation

According to plan, the Federal Aviation Administration will let drones into American skies by 2020. A report released last week by the Office of the Inspector General for the Department of Transportation is very, very skeptical that all is going according to plan. Titled, subtly, "FAA Faces Significant Barriers To Safely Integrate Unmanned Aircraft Systems Into the National Airspace System," the report outlines significant challenges to a future filled with flying robots.

As outlined in the FAA's roadmap, the first stage to integrating unmanned aircraft with manned flying machines in the same skies is establishing test sites. Selected in December, some of the test sites, like the one in Grand Forks, North Dakota, are already up and running. But moving from small test sites to a future of safely integrated skies may never happen.

The report, authored by Matthew E. Hampton, Assistant Inspector General for Aviation Audits, lays out three major failings of the FAA:

• First, following many years of working with industry, FAA has not reached consensus on standards for technology that would enable UAS to detect and avoid other aircraft and ensure reliable data links between ground stations and the unmanned aircraft they control.
• Second, FAA has not established a regulatory framework for UAS integration, such as aircraft certification requirements, standard air traffic procedures for safely managing UAS with manned aircraft, or an adequate controller training program for managing UAS.
• Third, FAA is not effectively collecting and analyzing UAS safety data to identify risks. This is because FAA has not developed procedures for ensuring that all UAS safety incidents are reported and tracked or a process for sharing UAS safety data with the U.S. Department of Defense (DoD), the largest user of UAS. Finally, FAA is not effectively managing its oversight of UAS operations. Although FAA established a UAS Integration Office, it has not clarified lines of reporting or established clear guidance for UAS regional inspectors on authorizing and overseeing UAS operations. Until FAA addresses these barriers, UAS integration will continue to move at a slow pace, and safety risks will remain. [emphasis added]

Nested within these challenges are further challenges still. The FAA wants two technologies to make drones safer. One is "sense and avoid," where the aircraft without onboard pilots can detect and move away from other aircraft, the way an onboard pilot could see something and steer clear. This technology isn't ready yet, though researchers are working on it. The other technology the FAA wants to be ready before integration is secure link technology, which will keep the pilot on the ground in contact with the drone at all times. Even the military struggles with this one. In 2010, a U.S. Navy Fire Scout drone lost link with its pilot and then flew into the highly restricted airspace over Washington, DC.

Besides technical challenges, there are legal issues. The FAA is a regulatory agency; its rules are designed to keep the sky safe by making sure everyone flying is on the same page. Yet their approach to drones, and especially commercial drone uses, is presently haphazard, as it occurs on a case-by-case basis.  In addition, drones are grouped into two categories: under 55 pounds, and over 55 pounds, which confuses model airplanes and small drones. Here too the Inspector General finds fault.

Further failings are found in data sharing, air traffic controller training, progress towards goals stated in the FAA's roadmap, and integrating the concerns of the many groups that want to use drones. It's a bleak report, and it ends with 11 suggestions for improvement. Roughly, they consist of better timelines, realistic goals, uniform metrics, and standardizing the way the FAA thinks about drones.

It's a long road to the future of drone-filled skies. This report is the surest sign yet that 2020 is too optimistic a date for drone integration. If the FAA follows the steps recommended, and if the technology develops on schedule, there's still a chance for a drone-tastic future, but it's going to take a lot if work and a lot of change by the agency to get there.

aliens

Copyright 2013 RML Echo Films, LLC (2)

Will the aliens be robots?

The star, Echo, has the metallic skin and glowing-bulb eyes of a mechanical being—something like the machines SETI Institute senior astronomer Seth Shostak believes we’ll initially encounter (as opposed to fleshier visitors like E.T.). “I think it’s likely to be some sort of artificial intelligence,” he says. With humanity closing in on AI capabilities, he expects such systems will be common among advanced creatures.

Why assume E.T. is hostile?

This movie joins a tiny subgenre of films about peaceful aliens—a concept that might not be as naïve as it sounds. Carl Sagan argued that any species that makes radio contact is likely to have outgrown its warlike tendencies. “In the long run, the aggressive civilizations destroy themselves, almost always,” the alien in Sagan’s 1985 novel, Contact, tells the human protagonist. “It’s their nature. They can’t help it.” 

Could a spacecraft crash undetected?

A Starship Enterprise–size ship would raise alarms, Shostak says, but a smaller craft might not. NASA’s asteroid-detection capabilities bottom out at objects 330 feet across; the meteor that unexpectedly exploded over Russia in 2013 was estimated to be about 65 feet. The landing would also have to be soft; a major crash would cause the kind of seismic waves that lead scientists to meteorite-landing sites. 

This article originally appeared in the August 2014 issue of Popular Science. 

Writing Robot

Mirko Tobias Schaefer/Gastev on Flickr, CC BY 2.0

The venerated AP now plans to generate and sell thousands of automated business articles a year. The robot-written stories will bring up the AP's story count in this area by an order of magnitude, Poynter reports.

Over the past few years, several news organizations have used robot writers for some of their stories. Forbes uses algorithms from the startup Narrative Science to find and write short stories about companies whose stocks are doing well. The Los Angeles Times uses bots, developed by one of its own journalists, to publish immediate reports about area earthquakes and homicides. The AP will use business reports generated by a company called Automated Insights, Poynter reports.

Finance and sports are the usual targets of robot reporting. Both are a bit robotic by nature. The most basic reports involve plugging numbers from a database into one of a few standard narratives. That said, automatically written stories don't have to be too terrible to read. One small, recent study even found human readers can't always tell the difference between people- and algorithm-written sports stories.

The biggest argument for robot journalism is that it frees human reporters to do the kind of deeper reporting only people can do. That is likely true, and pretty cool. Another is that auto-writers are able to accurately process an inhuman amount of data, then present it in a way that humans like to see: in words. ProPublica did this last year for one of its interactive stories about public schools.

Meanwhile, we human writers keep trying to prove our charm is irreplaceable, but we're not sure how well we're doing. If only we could do a sentiment analysis on our readers.

Tufted ground squirrel

HOSCAP Borneo

Behold the tufted ground squirrel, one of the strangest tree-dwelling rodents found on Earth. Native to Borneo, it is rarely seen--one camera trap study in a park on the island turned up only one of these squirrels, known scientifically as Rheithrosciurus macrotis. When they have been spotted, their large tail has stuck out.

More of the furry critters were photographed in a more recent study, published in Taprobanica. And the researchers made quite a discovery: The squirrel's tail is 130 percent the mass of the rest of its body, giving this species the largest tail-to-body ratio of any known mammal. Its closest competitors in the "bushiest tail" category are ring-tailed cats, striped possums and squirrel gliders, though in each case these animals' fluffy appendages are (merely) the same mass as their non-tail body.

But why would it be advantageous to have such a large tail? The researchers suspected it could be used to deter predators such as Sunda clouded leopards, by making the squirrels appear bigger, or making it harder for the big cats to get a good hold on the rodents.  

Fluffy tail

Another tufted ground squirrel

D. Augeri / Taprobanica

The squirrels are known to eat the seeds of Malva parviflora, also known as cheeseweed. This weedy plant, found in Africa and Asia and elsewhere, has anti-inflammatory and anti-oxidant properties. Perhaps that helps them grow such a bushy tail. (Pure speculation, of course.) More bizarrely, the squirrels are said to stalk deer and other larger animals. As local hunters told the researchers:

The researchers wrote that they would keep an open mind about these stories. After all, they added, "another seemingly unlikely hunter story from Borneo of deer of the genus Tragulus hiding underwater for long periods of time also turned out to be true."

An 1856 drawing of a tufted ground squirrel by Joseph Wolf.

Proceedings of the Zoological Society of London

[h/t Science magazine]

Lego plant

Lego walls hold a transparent growth medium mimicking soil. The versatile setup allows researchers to see how plants respond to increasing levels of nutrients, which are here dyed orange.

Lind et al / PLOS ONE

Legos are great for making all kinds of things--castles, pirate ships and functioning miniature dockyards, as I can tell you from experience. But a new study found that they are absolutely excellent for something unexpected: studying the growth of plants and the delicate expansion of their roots. 

The reasoning of the researchers, from the University of Iowa, went like this: Greenhouses are really large. Micro-fluidic devices used to grow plants and test unique growing conditions are really expensive. So, what about Legos? Transparent blocks of the common toy are perfect for creating the micro-environments needed to study plants and their roots, the researchers wrote in the journal PLOS ONE--they are cheap, abundant, easy to re-arrange, and can be tailor-made with CAD software. The Legos can even be sterilized in an autoclave (basically like a small oven for sanitizing lab equipment) without melting, while remaining translucent.

So far the scientists have used Legos to study and produce images of the real-time growth of the roots of garden cress. The Legos are perfect for holding the see-through growth medium, a type of agar. The Legos have also allowed the researchers to study differences in soil/agar that aren't easy to produce with larger equipment, and they're great for building in air pockets, solid barriers between plots, and chemical and microbial gradients that could for example show how roots respond to increasing concentrations of fertilizer.

Lind et al / PLOS ONE

[PLOS ONE]

Copperhead on a Tigershark Drone

Sandia National Laboratories

Improvised explosive devices are the scourge of the modern battlefield, assembled from simple components and placed along frequently patrolled roads to ambush troops walking by. The American military used a special sensor named Copperhead attached to drones to find these IEDs placed in Afghanistan and Iraq. With U.S. involvement in the war in Afghanistan winding down, Sandia National Labs, the developer of Copperhead, is handing the technology over to the United States Army.

Copperhead is built from a MiniSAR, or Miniaturized Synthetic Aperture Radar. MiniSAR works by sending out a microwave pulse, reading the reflections of that pulse, and then stitching them together into an image. Copperhead took this technology and added in an algorithm that keeps the entire field of view in the same scale. Previously, MiniSAR had a problem plotting slopes, which limits the technology's usefulness in over mountainous terrain. Additionaly, because MiniSAR is a radar technology, it can see through smoke, dust, and weather. Dust and hills aren't ideal lab conditions, but they're very much battlefield ones.

Here's how Copperhead finds IEDs. It takes two images of the same area, taken at different times, and like the dullest "find six differences" cartoon, it highlights discrepancies. Sometimes this can be minor, like the grass mowed on a lawn in the past twenty minutes. And sometimes this can reveal a bigger threat worth investigating further, like an awkwardly placed box by the side of the road that wasn't there before, and could be concealing a roadside bomb. 

The Copperhead technology was first deployed to Afghanistan and Iraq in 2009 for combat tests, and was funded as a research project. According to Bryan Burns, a senior engineer at Sandia National Labs, the transfer means Copperhead goes from a research project used in war to a tool available for the Army. Burns tells Popular Science:

Pills of the Opioid Painkiller OxyContin

U.S. Drug Enforcement Administration

Doctors in Alabama give out almost three times as many opioid painkiller prescriptions as doctors in Hawaii. Doctors in the Northeast write more prescriptions for high-dose and long-acting opioids than anywhere else in the U.S. These numbers and more come from a survey that scientists from the U.S. Centers for Disease Control and Prevention recently analyzed. The survey couldn't answer why doctors in some states prescribe opioids so much more often than others, but it does show some peculiar regional trends.

Opioid painkillers—a powerful class of medicines that includes oxycodone and fentanyl—can be important treatments for people with chronic pain. At the same time, some statistics indicate prescription opioids are the number-one cause of overdose deaths in the U.S., topping even the numbers of deaths associated with heroin and cocaine. (Although there's certainly controversy about how you can tell whether somebody died of an overdose, or whether she happened to die with drugs in her body.) In any case, many people are worried that opioids are overused in the U.S., including certain doctors' groups and government agencies.

Here's a map showing states' rates of overall opioid painkiller prescriptions. It shows the numbers of opioid prescriptions written in each state, per 100 people. There are a lot of opioid prescriptions in the South:

Opioid Prescriptions Per 100 People, 2012

From this CDC Vital Signs report by Leonard J. Paulozzi et al.

Incidentally, other studies have found southern states give out the most antibiotic prescriptions and the most prescriptions for stimulants for kids as well.

Meanwhile, doctors in the Northeast and certain western states are more likely than doctors elsewhere to give their patients high-dose and long-acting opioids:

Long-Acting Opioid Prescriptions Per 100 People, 2012

From this CDC Vital Signs report by Leonard J. Paulozzi et al.

High-Dose Opioid Prescriptions Per 100 People, 2012

From this CDC Vital Signs report by Leonard J. Paulozzi et al.

In a call for reporters, CDC Director Tom Frieden called the differences between states' opioid prescribing rates "remarkable." Agency officials think unnecessary prescriptions, along with a small number of fraudulent prescriptions, are to blame for the darkest-blue states: "That variability suggests to us that there's a lot of overprescribing going on," Frieden said.

The centers want high-prescribing states to bring down their numbers as a way to combat overdoses. A CDC scientist on the call, Leonard Paulozzi, pointed to previous agency research that found that states with the highest opioid sales also had the highest rates of opioid overdose deaths.

Among other strategies, Frieden suggested states beef up their prescription-monitoring programs so officials are able to see, in real time, when doctors prescribe unusual amounts of opioids. There's sure to be debate about this. Many advocacy groups say it's already too difficult for legitimate patients to get the painkillers they need. It's possible over- and under-prescription are happening at the same time.

One thing is for sure. There's just no national consensus among scientists and doctors about how opioid painkillers should be used.

Criss-Crossed Contrails

The condensation trails that form behind high-altitude aircraft, or contrails, are one of the most visible signs of the human impact on the atmosphere. On February 15, 2013, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this view of numerous contrails over Portugal and Spain.

NASA Earth Observatory

Greenhouse gas pollution from jet aircraft comes mainly in two forms: carbon dioxide emissions from burning jet fuel, and condensation trails, or “contrails,” which typically form behind aircraft when they encounter atmospheric temperature and air pressure conditions that allow water vapor or ice crystals in the air, or vapor from jet engine exhaust, to condense.

A few more clouds in the sky might not seem like a big deal. But clouds warm temperatures because they, too, reflect space-bound heat back towards the Earth's surface. Aviation contrails--which are essentially artificial clouds--contribute more to human-propelled climate change than all the CO₂ pollution created in the history of fuel-powered aviation, according to a 2011 study published in Nature Climate Change.

So Dr. Emma Irvine, a meteorologist at the U.K.'s University of Reading, and colleagues decided to examine what the climatic trade-offs would be between re-routing flights to avoid contrail-friendly conditions - called “ice-supersaturated regions” or ISSRs - and the increase of heat-trapping CO₂ pollution a longer flight would create.

The equation (or “framework” in scientific terms) they devised, says Irvine, shows that “you can add extra distance on to a flight to avoid making a contrail, but still reduce overall climate impact of the flight.”

One reason is that Irvine and team decided to exclude altitude changes from the re-routing equation – important, she says, because different jets fly most fuel-efficiently at different altitudes.

Another is that the amount of CO₂ a jet engine emits is determined by not just distance, but also fuel flow, which varies depending upon type of aircraft. The smallest jets, which have the slowest fuel flow and the lightest weights, can travel between 4 and 10 times further by distance (depending on whether one is considering the impacts on a 20, 50, or 100-year time horizon) to avoid ice-supersaturated regions, according to Irvine's equation, and still have less global warming impact than if they took the contrail-forming route instead.

The largest jets, which burn fuel at a much faster rate, showed much less flexibility between extending distance and emitting more CO₂, vs encountering ice-supersaturated regions and forming a contrail. Even looking at a 100-year time horizon for impact, very large jets could not travel more than three times the distance of their original routes before the CO₂ harms outweighed the advantages of avoiding contrail formation.

The researchers do note several unknowns in using this strategy to cut aviation's global warming impacts, including whether we can develop “highly accurate forecasts of ISSRs where potential contrails form,” or assess accurately the climate change effects of a potential contrail.  There would also be “air traffic control and other operational and economic considerations.”

“Nevertheless, despite the uncertainties,” they conclude,

the calculations presented here indicate that once a metric (and time horizon) choice has been made, guidance can be given as to whether it is beneficial to divert to avoid contrails. So for example, adding 100 km distance to a flight to avoid making a contrail would seem beneficial for many of the cases presented here, and other parameter choices...could allow significantly longer diversions.

Irvine's research appears in the latest issue of Environmental Research Letters.

Click here for more of Popular Science's aviation and drones coverage.

Chilean Devil Ray

WHOI/Nuno Sá

Something comes along now and then that demonstrates--pleasantly--just how much we have yet to discover about the ocean. Today, it's this: We've long thought that warmth-loving devil rays dwelled solely at the ocean's surface, called the "euphotic" or sunlight zone. But newly published research shows that these fish regularly dive over 1.118 miles (1.8 kilometers) down, putting the species among the deepest-diving marine animals known, such as Cuvier’s beaked whales (1.86 miles deep), and whale sharks (1.18 miles deep).

In the process of learning that devil rays regularly make these dramatic dives, scientists may have solved an anatomical mystery as well: the purpose of the ray's rete mirabile, a mass of blood vessels in the front of its skull that keep its brain warm.

Simon Thorrold of Woods Hole Oceanographic Institution and his team put satellite tags on 15 Chilean devil rays, and tracked their movement for several months. In addition to recording their surface migrations across the tropical and subtropical North Atlantic Ocean, the tags documented the rays diving deep into the ocean's bathyal zone. Water temperatures at this depth are below 39 degrees Fahrenheit.

Dive Profiles from Tagged Devil Rays

Tagged devil rays dove from the ocean's surface to depths in excess of 1.118 miles (1.8 kilometers), where waters are nearly freezing cold. "(a) Depth and temperature profiles recorded at 75-second intervals from three representative dives initiated during daylight hours (6.00 am–6.00 pm local time). (b) Depth and temperature profiles recorded at 75-second intervals from three representative dives initiated during nighttime hours (6.00 pm–6.00 am local time)."

Thorrold et al./Nature Communications

While more data are needed, the researchers say it's likely the rays were hunting and feeding on tasty small fish—an active behavior that would require a well-warmed brain to do well.

Before this study, "[I]t was a mystery as to why they had this system, which is a way of keeping brain activity high, even in a cold environment," Thorrold told BBC News. "We looked at the data and of course, it made complete sense" that the retia mirabilia helps the rays remain alert and efficient as they feed in the cold deep waters.

Read the study, which has just been published in open format by the journal Nature Communications--no subscription required to enjoy the science.

A Puck of Superconducting Material Levitates Over a Permanent Magnet

University of Cambridge

Engineers have trapped the strongest-ever magnetic field inside a superconductor. The result was a super-powerful magnet—about six times as strong as the magnets found in an MRI machine—about the size of a human thumb.

The research is part of an ongoing effort to create superconductor magnets that don't need to be cooled to extreme temperatures. Such magnets could go into flywheels for energy storage, separators for purifying metals or cleaning pollution, and maglev trains, according to a news item from the University of Cambridge. The researchers involved in making this new superconductor came from Cambridge, the National High Magnetic Field Laboratory in Florida, and the Boeing Company.

This new superconductor magnet has a strength of 17.6 teslas. It also works at temperatures above that of the boiling point of nitrogen (-196 degrees Celsius), so it should be cheaper and easier to maintain than a conventional superconductor, which requires temperatures near absolute zero (-273 degrees Celsius).

One of the researchers' big challenges in making this superconductor magnet was ensuring it stayed intact. Lines of magnetic flux in a superconductor strongly repel each other. The material researchers used to make this superconductor, gadolinium barium copper oxide, is brittle, ceramic-like stuff. Trapping this strong of a magnetic field inside this material could cause it to explode. To strengthen the material, researchers altered its structure at a molecular level. They also "shrink-wrapped" it with a band of stainless steel.

Next, the researchers plan to try to make a superconductor trap a magnetic field of 20 teslas or greater, according to the National High Magnetic Field Laboratory. They're also trying to develop practical applications for what they've got.

They published their work last week in the journal Superconductor Science and Technology.

[University of Cambridge, National High Magnetic Field Laboratory]

Photo Of A Mouse Fetus From The STAP Stem Cells Work

Haruko Obokata

The journal Nature has finally retracted two major studies it published in January, which claimed to have found new and easy ways to turn regular cells into stem cells. Not long after the papers first went online, independent scientists began noticing apparent plagiarism within them. Independent teams were unable to replicate the papers' findings. Later, a genetic test found that the stem cells described in the papers were not what the papers claimed.

All the scientists involved in the studies have now agreed to retract the papers, according to a letter Nature published online today. The letter describes what the retraction looks like:

The letter continues with the results of Nature's own inquiry into whether experts at the journal should have caught these problems sooner. The journal's editors decided they couldn't have:

Still, the journal is apparently making some changes, in hopes of catching poorly done and fraudulent papers in the future:

The journal published a separate article with technical details on the retraction. 

Glassware for beer comes in various shapes and sizes

Photograph by Jonathon Kambouris

Brewers spend years perfecting a chocolaty stout or balanced IPA, but when it comes to showcasing their craft, a pint glass serves about as well as a bucket. To rectify this crime against taste, the glass makers at Spiegelau created a line of beer-specific glassware. The vessels ($24.90 for two stout or two IPA) better convey the complexity of craft brews—and keep them cold and foamy longer.

1) Fizzier IPAs

Bubbles form at nucleation sites, such as imperfections in glass. The IPA glass has a ribbed base, which boosts surface area and, with it, potential sites, so bubbles can form over the life of the pour. .

2) Enhanced aroma

The curved bowl of the IPA glass directs hops’ aroma—which accounts for up to 75 percent of beer’s taste—into your nostrils. Beer lands on the middle of the tongue, so it hits more taste buds.

3) Frothier stout

When beer pours over the edge of the bowl and into the base, turbulence froths nitrogen into stout’s signature head. With every sip, the angled base re-creates the initial pour, reviving the fizz.

Tested: Thinner Glass, Colder Beer?

The more quartz there is in a glass, the thinner it can be. Spiegelau uses almost-pure quartz to make extremely thin walls, which it claims will keep beer colder longer. In our taste test, beer poured into a Spiegelau glass was 2.5°F colder after five minutes than beer poured into a pint glass.

Problem With Pint Glasses

Spiegelau claims that the straight walls of a pint let beer flood into the mouth, triggering an antidrowning instinct that causes the tongue to press against the teeth. If this occurs, beer may not hit every type of taste bud; it could miss sweet ones and taste bitter.

A thick-walled pint glass has the potential to hold onto and, therefore, transfer more heat into a beverage than a glass with thinner walls. Warm beer traps less carbon dioxide than cold beer does, so tepid brews can lose their fizz faster.

This article originally appeared in the July 2014 issue of Popular Science.

Cooksey, Allen/NIST

These are some nice color swatches, don't you think? I can just imagine them as decorative bathroom tiles. But what if I told you these are samples of people's skin? They are! The top set is a series of photos of the skin from the inside of different people's forearms. The bottom set are images of the same people's skin, but the images were enhanced with techniques researchers are developing for medical diagnoses and biometric applications.

You might notice that while it's difficult to tell many of the photos in the top set apart, they're much more varied in the bottom set. That's because different people's skin reflects electromagnetic waves differently. The human eye can only see the narrow band of electromagnetic waves in the visible light range. The reflectance processing technique takes advantage of waves that aren't visible to the naked eye, from infrared light to ultraviolet light.

Because the enhanced images are so different from one another, researchers hope they might be used to identify people in the future. Imagine a face or fingerprint reader that takes into account not only your features, but also your skin tone, as measured by a wide range of light. In addition, some research groups are hoping to develop skin-imaging techniques that will tell doctors more about a person's health. Certain wavelengths of light could show how well skin is healing around a wound, for example.

Before researchers can put these applications to work, however, they have some basics to figure out. The images above come from an effort at the U.S. National Institute of Standards and Technology to determine the best wavelengths of light to use for telling people apart by their skin. The researchers also wanted to check that the differences between people's skin were greater than the error bars of the instruments they used to measure skin reflectance. Their sample size was small—28 people—and not exactly random. (They appear to have simply nabbed people walking down the hall at NIST.) With this preliminary data, however, they determined the differences between individuals really are greater than instrument error, and the results suggest that visible and near-infrared wavelengths may be best for identification purposes. 

The researchers wrote a paper about their work and presented it last month at a conference hosted by the International Society for Optics and Photonics.