Popular ScienceApril 2013的目錄

ON THE LAST Sunday before this issue went to press, the lights went out at the Super Bowl. I sat there, gaping, with a drink in my hand, as the ads, the field, Phil Simms, and one of the biggest televised events went dark in front of 108 million viewers. And then I put down the drink and got on the phone. The editors immediately went to work sorting things out. Was this a failure of Entergy, the local utility? Had the incredible power demands of the Super Bowl outstripped the rebuilt infrastructure of post-Katrina New Orleans? And was this the most damning evidence yet that the country needs the fabled smart grid we've been weighing all these years? We interviewed everyone we could find who'd been affected by the…

Projecting a large image in a small room is almost impossible, an unfortunate result of how most projectors work. In them, light passes from a bulb though a colored LCD panel and diffuses across a room. The farther back the projector, the more the light spreads, expanding the image; for example, a standard projector 12 feet from the wall produces a 100-inch picture. To create the same image from less than two feet away, engineers at LG used lasers instead of a bulb in the new Laser TV HD projector. The stronger, less-diffuse light is easier to manipulate at short distances. The projector alters images in two ways. First, its processor runs the picture data through algorithms that expand the bottom corners of the image to compensate for the severe…

IN THE PRIVACY of their own bathrooms, people can find out whether they're pregnant or have HIV. They can even swab for DNA to unravel their ancestry. Yet it's difficult to answer simpler questions, like “Do I have the flu?” That's because the most advanced diagnostic device in most medicine cabinets is a thermometer. Regularly measuring and understanding anything more complex than body temperature, such as respiratory rates and heart rhythms, is a physician's job. So patients often go to the doctor when they don't need to or don't go when they should. By providing doctors with better data and patients with better decision-making tools, personal health monitors and diagnostics could break that cycle. In the last few years, medical-device manufacturers have begun using miniaturized sensors and mobile phones to…

“Our miniature bio-bot is made of a flexible polymer and living heart cells. The cells beat together, creating a contracting and releasing motion that inches the bot forward. We use a 3-D printer to build the bot's body layer by layer out of a hydrogel—the material contact lenses are made from. It's about a centimeter long, with a flexible leg that rests on a shorter leg like a cantilever. We also print collagen on the underside of the long leg so that the living cells can attach to it. After printing, we bathe the structure in a solution of rat cardiac cells and support cells called fibroblasts, and the cells attach to the collagen-infused area. We store the bio-bot in an incubator that is 98°F (about the body temperature of…

On a research trip to the Coral Sea in the southwest Pacific last fall, geologists noticed a discrepancy between their maps and the horizon: A 16-mile-long island was missing. In its place, the scientists saw only water. “Sandy Island”—first mapped in 1902—had already been dropped by some maps but persisted in the World Vector Shoreline database, a main resource incorporated into many digital maps. Even Google Earth had included the island but has since removed it. On Saturn's moon Titan, liquid methane plays the role of water, raining from the skies and filling the rivers and seas. Last September, as NASA's Cassini spacecraft passed by Titan, its radar captured images of a methane river—the largest river system found outside our planet to date. The 250-mile body flows downhill into a…

T—3:00:00 Falcon Heavy is ready on the launch-pad at Cape Canaveral. Engineers time liftoff to achieve the optimal flight path and desired orbit. T—0:10:30 The countdown begins. All actions from here forward are pre-programmed, although Mission Control can abort the mission at any time. T—0:02:30 The launch director issues the final launch command. T—0:00:40 Propellant tanks are pressurized. T—0:00:03 First-stage engines ignite. 0:00:00 The onboard rocket computer commands the launch mount to release. Liftoff. T+0:01:25 The rocket reaches maximum aerodynamic pressure; mechanical stress peaks. T+0:02:45 The rocket has now burned enough fuel (thus decreasing its mass) that the center core engines can throttle down. T+0:03:00 The side cores separate and fall into the ocean, while the center core's nine Merlin engines continue to burn for approximately 30 seconds. T+0:03:30 The…

If you've ever wondered how boneless chicken parts end up that way, take a peek inside one of the 4,000 or so poultry processing plants in the U.S. Workers man massive assembly lines to scald, pluck, gut, slice, and wrap an estimated nine billion birds annually. Unsurprisingly, work in poultry plants is dirty and dangerous. The job of chicken deboner (who cuts through the shoulder joint to separate the wing from the body) is particularly brutal since it requires performing repetitive motions with a knife for hours on end in a room the temperature of a refrigerator. If ever there was a job for a robot, this is it. But teaching a machine to carve poultry is difficult. No two chickens are the same, and each cut must be perfect.…

The fundamentals of earthquake mechanics are simple: Pieces of rock slip past one another along a fault to release pent-up energy. Some of that energy ripples outward, causing seismic waves that shake the earth. But how long it takes and exactly how the energy dissipates has remained elusive. To discern these processes, researchers recently built a machine at the University of Oklahoma to mimic what happens inside the earth's crust. Two slabs of rock, ground against each other by a 500-pound flywheel, simulate fault stresses to provide data on the energetics of a tremor. “Most of the energy seems to go into heating, and some goes into grinding up material,” says David Lockner, a geophysicist with the U.S. Geological Survey in Menlo Park, California. “What we're all familiar with—the energy…

LAST SEPTEMBER, a few hundred scientists, engineers and space enthusiasts gathered at the Hyatt Hotel in downtown Houston for the second public meeting of 100 Year Starship. The group is run by former astronaut Mae Jemison and funded by DARPA. Its mission is to “make the capability of human travel beyond our solar system to another star a reality within the next 100 years.” For most of the attendees at the conference, advances in manned space exploration have been frustratingly slow in coming. Despite billions of dollars spent over the last few decades, space agencies aren't capable of much more than they were in the 1960s. They may be capable of less. 100 Year Starship intends to accelerate the process of interstellar travel by identifying and developing promising technologies. Over…

DESPITE THE CRYPTIC NAME and anonymous office-park architecture, the nature of the enterprise located at AFB International is clear the moment you sit down for a meeting. The conference room smells like kibble. One wall, entirely glass, looks onto a small-scale kibble-extrusion plant where men and women in lab coats and blue sanitary shoe covers tootle here and there pushing metal carts. AFB makes flavor coatings for dry pet foods. To test the coatings, the company needs to make small batches of plain kibble to put them on. The coated kibbles are then served to consumers: Spanky, Thomas, Skipper, Porkchop, Mohammid, Elvis, Sandi, Bela, Yankee, Fergie, Murphy, Limburger, and some 300 other dogs and cats that reside at the company's Palatability Assessment Resource Center (PARC), about an hour's drive from…

Maintaining a fleet of machines with different engines is arduous and expensive. The Global Village Construction Set attacks both problems with a single, versatile power source called the Power Cube. Below are a few of the machines and capabilities that a cube could enable by 2015. MicrotractorA tiller small enough to push around a field and prepare the soil for planting seeds TruckA general-purpose off-road vehicle that can lug hefty loads for miles Hay CutterSimultaneously mows down large fields of grass and prepares hay for a bailing machine SawmillCuts unwieldy logs into lumber BulldozerBig-bladed tractor that can clear roads, dig water reservoirs, build up berms, and more LiberatorDirt goes in, bricks come out—makes nearly 1,000 small blocks an hour Press ForgeUses hydraulic power to punch molten metal into any number…

You don't need costly gadgets and software to turn real-world stuff into precise 3-D models—just a digital camera and Autodesk's free 123D Catch service. Take at least 20 photos of an object from various angles and upload them to the site, where algorithms stitch the pics into a meticulous 3-D rendering. Then polish away any errors using the editing program. You can order 3-D-printed or laser-cut models, download the data to use with your own gear, or share it online with other enthusiasts.…

Q:What would it feel like to travel at warp speed? SHORT ANSWER It wouldn't feel like much of anything. LONG ANSWER If it were really possible to build a warp drive, using it wouldn't make you fly back into your seat as in a science-fiction movie. “Inside the spaceship, it would feel absolutely normal,” says physicist Dave Goldberg of Drexel University. “You would be weightless, of course, because you wouldn't have any acceleration on you at all.” That assumes you're on the inside of what's known as an Alcubierre Bubble—a hypothetical construct that could allow a patch of space to travel at many times the speed of light [see “Warp Factor,” p. 50]. The crew of a spaceship that had entered such a bubble probably wouldn't have any sense of…

Kudos for publishing Dan Baum's comprehensive railroad safety article [“Derailed,” February 2013]. It provided a perspective that is easily lost when the events involved are widely dispersed in time and place. Doug KoehlerMarshfield, Wis. Railroads are by far the safest, most efficient, and most environmentally friendly mode of transportation. Why not do a story on 18-wheelers? Studies have shown that if big trucks paid road-use taxes commensurate with the expense of maintaining roads due to truck traffic, much of the freight that goes by truck would go by rail instead. That cargo could be shipped more safely, more cheaply, and with less environmental impact. John ShominLiberal, Mo.…

In January 2009, General Motors unveiled the luxury cousin of the Chevrolet Volt—the Cadillac Converj concept. Yet almost immediately, GM started sending mixed signals. One moment the Converj was approved for production; the next it was on hold. Finally, at the most recent Detroit Auto Show in January, GM revealed the car the Converj had become: the 2014 Cadillac ELR. The two-door plug-in hybrid pairs a powertrain pulled straight from the Volt with Cadillac styling and a high-toned interior. The car is scheduled to go into production late this year. But it's still unclear how committed to it GM actually is. At the Detroit show, group vice president Bob Ferguson insisted that the ELR will be built only in very limited numbers. But if drivers embrace the car, GM executives…

DRILLING IN THE ARCTIC is a matter of when and not if. With summer sea ice having declined 30 percent since 1979 and continuing to shrink, companies are racing to prospect above 60° North. The Arctic contains an estimated 90 billion barrels of recoverable oil and 1,670 trillion cubic feet of natural gas—nearly a quarter of the world's undiscovered supply. Royal Dutch Shell has already spent $4.5 billion drilling off the coast of northern Alaska. ConocoPhillips wants to sink a well in the Chukchi Sea by next year. And Exxon announced a partnership with a Russian company to drill in the waters north of Siberia in 2015. But the industry's current fleet of equipment—floating rigs and oil- and gas-processing platforms—is ill-equipped for the Arctic's Manhattan-size icebergs and 60mph winds. To…

It's not easy to see what's going on in a handful of dirt, so some labs use gels and other substitutes to grow plants when they study them. Unfortunately, roots and most of the organisms that interact with them don't grow as well in fakes. That's why researchers at Scotland's nonprofit James Hutton Institute have developed a transparent soil that more closely resembles the real deal. For the main ingredient, they use small particles of the polymer Nafion, which holds nutrients and becomes clear when mixed with water. With the transparent soil, scientists will be able to observe how roots grow, take up nutrients, and associate with microbes without having to destroy the setup. Using the soil, the researchers have already tagged E. coli with a fluorescent marker and became…

For the past 50 years, radio astronomers who wanted to study the dense, spinning remains of former stars and the structures of galaxies have gone to Puerto Rico's Arecibo Observatory, home to the world's largest telescope dish. The instrument (which captures wavelengths from 3 cm to 6 m) lies cradled within a broad, circular depression in the ground, creating a 1,000-foot-wide aluminum crater amid jungle hills. Soon, however, astronomers will have an even more immense instrument at their disposal: China's $122-million Five-hundred-meter Aperture Spherical radio Telescope (FAST). Like Arecibo, FAST will rest in a slump created long ago by the collapse of a subterranean cave, but it will be in a more remote region, with less radio interference. And FAST will have two major advantages over Arecibo's telescope. First, its…

When the firm SpaceX launches its Falcon Heavy rocket into space late this year, the craft will become the mightiest rocket in the world. Only NASA's Saturn V, which sent Americans to the moon, has ever generated more power. In rockets, the most important measure of power is thrust. Falcon Heavy's 27 individual booster engines together generate 3.8 million pounds of thrust—enough to lift the 3.1-million-pound rocket and its 117,000-pound payload toward low-Earth orbit. The rocket's success is critical for both SpaceX and the U.S. space program: The Air Force has already hired SpaceX and its Falcon Heavy to send two satellites into orbit sometime in 2015. Falcon Heavy's first stage consists of three cores. All three cores operate together at liftoff. About T+2:45 minutes into flight, the center core…

DNA sequencing has revolutionized medicine and biomedical research. For example, DNA analysis can tell doctors which drug might work best against a particular cancer. But current technology usually sequences only short stretches of DNA and can take hours or days. To sequence anything longer than a few hundred base pairs, scientists mince up thousands of copies of the target DNA, sequence all the fragments, and use software to painstakingly reconstruct the order of the DNA bases by matching overlap within fragments. A new approach, called nanopore sequencing, can handle long strands of DNA at once, eliminating the need for overlap analysis. As a result, nanopore sequencers could be cheaper, faster, and more compact than other DNA sequencers. They can also accurately sequence stretches with many repeating base pairs. The MinION…

From the outside, galaxies appear as a mass of stars orbiting a dense center. But inside, they are more complex, with some groups of stars moving at different speeds or directions, in part because they originated from separate galaxies that collided billions of years ago. To untangle these disparate components of the Milky Way, the European Space Agency plans to launch Gaia in October. The two-ton craft will map a billion of our galaxy's more than 100 billion stars, collecting data on all three dimensions of each star's position as well as its speed, direction, color, and brightness. Knowing where stars are located and headed will help astronomers determine where they came from. And that could shed light on how our galaxy formed and evolved. The key to Gaia's success…

THE WARP DRIVE proposed by Miguel Alcubierre would achieve faster-than-light speeds by distorting space-time. The device would generate a field of negative energy that would squeeze or stretch space-time, creating a bubble. The bubble would ride the distortions like a surfer on a wave. As evidenced in the big bang, space-time can expand so quickly that objects move faster than the speed of light. The vertical dimension represents how much a given volume of space-time expands or contracts in Alcubierre's model. Positive values [red] imply an expansion. When space-time expands behind a craft, it propels the ship forward. Inside the warp bubble, neutral space-time would leave the ship undisturbed. Passengers would experience a gravitationally calm zero-G environment. Negative values [blue] imply a contraction in space-time. The contraction balances the expansion…

MARCIN JAKUBOWSKI didn't study fusion physics to become a farmer. But the Polish-American scientist grew more disillusioned with academia the longer he worked toward his doctorate. Researchers withheld data to compete for grants, he says, instead of collaborating to solve big problems. “The further I went in my Ph.D. program, the less value I felt I was contributing to society,” he says. Seeking a fresh start, Jakubowski bought 30 acres of Missouri farmland and a tractor. Life in relative seclusion proved uneventful until, one day in 2008, his tractor broke down for the second and last time, spurring him to start an open-source industrial revolution. To Jakubowski, the tractor seemed designed to fail. Why should he sink more money into fixing it or buy a replacement? He wanted a simple…

Every year I burn down my backyard. Not because I have an unhealthy fascination with fire (which I do), but because my backyard is native prairie. It needs regular burning to maintain the ecosystem. Sometimes I witness fire whirls—spinning columns of flame that last a few seconds and reach 30 to 40 feet into the air. But those are nothing compared to what much bigger backyards can create: fire tornadoes. Tornadoes are like upside-down drains. Water flowing down a sink spins as centrifugal force interacts with gravity. Similarly, when a column of warm air rises through cooler air, it can form a vortex. If that rising air contains fire, you get a fire whirl or, in extreme cases, a fire tornado—flaring monsters that can reach nearly a mile high and…

If your desk isn't cluttered, you aren't doing your job. Gadget-building geeks know this adage well, thanks to resistors. The tiny components police electricity's flow, yet it can take dozens of kinds to perfect a circuit (such as to spin a motor at a precise speed). Electronics hobbyist George Graves knew devices called decade boxes allowed users to dial in different levels of resistance, but retail models seemed expensive and confusing. So Graves built his own with used parts. Now you can too. Get eight decimal thumbwheel switches. Collect nine identical resistors for each switch, from 1 ohm through 10 megohms. (E.g., nine 1-ohm resistors for the first, nine 10-ohm resistors for the next, and so on.) Set aside one resistor in each set. Bend the leads of the other…

Q:What might live in those subglacial Antarctic lakes? SHORT ANSWER Rock-eating or super-oxygenated microbes. LONG ANSWER No one has ever sampled the ice-capped lakes of Antarctica, so scientists can only guess at what lives in their depths. “We really don't have any idea,” says Brent Christner, a microbiologist at Louisiana State University and member of one of the three teams that have been drilling into subglacial lakes. (Results are expected by the end of this year.) “But if there's a viable ecosystem in these environments, it has to be driven by chemical energy.” In such a system, organisms would probably have evolved to subsist on dissolved minerals, perhaps derived from bedrock ground beneath the ice. “On the seafloor, people have described how basalts are colonized by organisms that are fueled…

In the rainforests of South America, squirrel monkeys and capybaras would never meet. While squirrel monkeys live in trees up to 60 feet high, capybaras—the world's largest rodents—dwell along river banks. But at the Beekse Bergen Safari Park in the Netherlands, the two species have shared an enclosure for eight years now, and they seem to be friends. The monkeys ride and groom the capybaras. They even eat and play together. Interspecies relationships are more frequent between captive animals, says behavioral ecologist Marc Bekoff. Because keepers feed them, they can spend time getting to know their enclosure mates instead of foraging for food. In 2005, a similar arrangement at a zoo in Japan went sour when a capybara mauled a monkey to death. But Bekoff says that, for the most…

Fifteen years ago, Lego released the Mindstorms Robotics Invention System, and amateur roboticists went wild. With it, they could snap together motorized creations that they could program with an intelligent brick. Since then, the Mindstorms online community has shared more than 17,000 designs—as varied as automatic toilet flushers and bumper cars—and started robotics leagues and engineering curriculums. This summer, Lego will release the EV3, the first Mindstorms update in seven years. The kit will allow builders to create tens of thousands of new robots, all of which will be smarter, faster, and more responsive than before. 1 Intelligence upgrade The heart of the EV3 is an upgraded processing brick. A 300-megahertz processor runs up to 10 times faster than its predecessor, so the brick can control more appendages and monitor…

Installed atop a wellhead, a tree uses valves, gauges, and chokes to regulate oil and gas flow. A separator can remove water and sand from the oil and gas “wellstream” and then pump them into a separate storage reservoir. (Wastewater can also be reinjected into aging oil and gas fields to increase their pressure.) Multiphase boosters capable of handling varying proportions of oil and gas—plus any remaining sand and water—pump the processed hydrocarbons through seafloor pipes. Shell's compressor trains, which require 12.5 MW of power from a subsea electrical cable, can pressurize 15 million cubic meters of gas per day to increase its flow rate. Umbilicals include electrical lines, fiber-optic communication cables, and tubes that carry methanol to prevent icelike hydrate plugs from forming in pipelines.…

When NASA technicians saw the navigation system on the Morpheus lander prototype shut off less than a second after liftoff, they knew the craft was doomed. It was August, at Kennedy Space Center in Florida, and the 27th test flight; the previous 26 had gone well. But this time, the 3,400-pound vehicle flew 16 feet high and, without spatial data to guide it, fell to the ground, where it burst into a 50-foot fireball. The goal of Project Morpheus is to help develop a space vehicle that can land autonomously, and exploding prototypes are part of the process, says Jon Olansen, the project manager. “You just build another one and continue on,” he says. “What we've learned hasn't been lost.” An investigation finished in October concluded that vibration probably caused…

LAST SUMMER, researchers at Northwestern University set an unusual record: They created a material with the highest-ever ratio of surface to volume. A teaspoon's worth could hold the equivalent of eight tightly folded football fields. Such improbable materials could help us store methane far more efficiently, the researchers said, but they also represent the latest advance in the ancient struggle to do more with less. Surfaces are extremely useful, after all. They can hold energy, as in the case of batteries, or convey information or soak up light. But they also take up a lot of space. They can be heavy. Large surfaces, such as giant solar cells, are hard to maneuver. How can we have the best of both worlds? Along at least five dimensions. INFLATABILITY: An old trick,…

A beehive buzzes with thousands of genetically similar female honeybees. Some nurse their queen and her eggs while others fly out in search of pollen and nectar. For decades, scientists knew that bees took on new jobs as they aged, but a team of researchers recently discovered that chemical tags attached to the bees' DNA play an important role in determining their career paths. The tags, which are frequently methyl groups, control gene expression, which in turn affects how an organism behaves. Both the chemical tags and the behavior they induce appear to be reversible, says Arizona State University biologist Gro Amdam. Foraging bees, for instance, could become nurses if the hive requires it. Humans also carry epigenetic tags that may affect their behavior. Scientists found methyl groups attached to…

Coiling up extension cords by hand is tedious. Spring-activated spools aren't much better; the mechanisms break easily and can cause violent snapback at the end of the cord. Engineers at Texas-based Great Stuff motorized the entire process. Using a combination of sensors and circuitry, the RoboReel neatly winds 50 feet of cable in 10 seconds, saving time and frustration. The RoboReel's 12-gauge power cord contains four wires, only three of which transmit current. The fourth runs between the circuit board and a button on the outlet head, which the user presses to initiate retraction. Once the circuit board receives the signal, it starts the motor, which revs at 4,500 rpms. A combo gear transfers the motion to the 8.8-inch-diameter spool, rotating it at about five feet per second. Opposite the…

Touchscreens treat all fleshy finger pads alike: Most detect a simple change in electrical current or in sound or light waves regardless of who is swiping. Researchers at Disney Research, Pittsburgh, have built a touchscreen that can discriminate between users. Every person's body has its own bone density, muscle mass, blood volume, and water content. The device, called Touché, sends a series of harmless currents through a user's body. Physiological differences produce differences in the body's impedance of that current. Touché measures this unique capacitive signature. Scientists could apply capacitive fingerprinting to any touchscreen, or to other ubiquitous objects, such as doorknobs and furniture, turning the world into an interactive device. Touché is still in development, and plans for commercialization, alas, are top secret. Capacitive sensors found in most existing…

The fastest chemical rocket ever, the Star-48 engine was built to launch satellites and was recently incorporated into the New Horizons probe, which took off in 2006. Powered by burning a mixture of ammonium perchlorate and aluminum, it boosted the Pluto-bound probe to approximately 36,000 miles per hour. New Horizons should reach Pluto and its moons by July 2015. FIRST USED FOR PROPULSION: 1980 Ion thrusters rely on electromagnetic effects to accelerate charged particles out the back of a spacecraft, generating propulsive force. Up to 50 times as efficient as chemical rockets, they are now primarily used for satellite station-keeping. NASA's Deep Space 1, launched in 1998, was the first probe to use an ion engine for main propulsion. Dawn, which is currently exploring the asteroid belt, also uses one.…

Two Power Cubes, each a 28-horsepower gasoline engine that drives a hydraulic pump (inset), lend the LifeTrac its muscle. Quick-connect mounts let users swap cubes into other machines. Hydraulic motors drive the wheels, which operate in pairs to move the 4,000-pound tractor on tank-like treads. When equipped with two Power Cubes, the LifeTrac can drag two tons of weight. LifeTrac's creators designed their multi-purpose tractor around a frame of sturdy, four-inch-wide steel tubes. Loader arms made from the tubes can lift loads weighing up to four tons. Versatility defines the LifeTrac. In addition to a simple shovel, Open Source Ecology is prototyping attachments such as seeders, rototillers, well-drilling rigs, balers, and brick presses.…

The Addams Family's Uncle Fester is famous for popping lightbulbs into his mouth and making them glow. The TV trick inspired Kip Kedersha, a fan of the series, to build a prank lamp using an LED, batteries, and an old bulb. Create your own and light up a room on April 1. Wearing thick gloves, carefully twist a glass lightbulb out of its metal base and save both parts. Discard the filament. Solder a 2-inch wire to the base's inside center and another to the side. Stack and zip-tie two three-volt button batteries. To the short lead (anode)of a white LED, solder the center wire. Tape the other wire to the battery pack's negative end. Tape one end of a third wire to the battery pack's positive terminal. Solder the…

Q:Do lobotomies work? SHORT ANSWER Surprisingly, yes. LONG ANSWER The modern lobotomy originated in the 1930s, when doctors realized that by severing fiber tracts connected to the frontal lobe, they could help patients overcome certain psychiatric problems, such as intractable depression and anxiety. Over the next two decades, the procedure would become simple and popular, completed by poking a sharpened tool above the eyeball. According to one study, about two thirds of patients showed improvement after surgery. Unfortunately, not all lobotomy practition-ers were responsible, and the technique left some patients with severe side effects, including seizures, lethargy, changes in personality, and incontinence. In response, doctors refined their techniques. They replaced the lobotomy with more specialized approaches: the cingulotomy, the anterior capsulotomy, and the subcaudate tractotomy. Studies of these procedures found…

The Polaroid SX-70 was an amateur photographer's dream: a pocket camera that could produce vivid, durable color photos nearly instantly. When Popular Science reviewed the collapsible 1.5-pound camera in January 1973, we called it “the most fiendishly clever invention in the history of photography” and praised Polaroid founder Edwin H. Land as the creator of “a pocketful of miracles.” The single-lens reflex camera, along with its self-developing, mess-free film, would soon gain a cult following that included Ansel Adams and Andy Warhol. “Who ever heard of a camera that does everything except ask the subject to look at the birdie and then hands you the picture on a platter?”—Arthur Fisher, editor Aim Light from the subject enters through the lens and hits a slanted mirror, which directs it onto a…