Antarctica's Ice

Antarctica's subglacial lakes, Vostok and Whillans, reveal what life might be like in icy worlds.



A drill cut half a mile through the Antarctic Ice Sheet to subglacial Lake Whillans in January 2013.

In January, climatologist Vladimir Lipenkov laid a disk of ice onto a light box in an Antarctic lab. The ice sparkled in a kaleidoscope of reds, blues and yellows as light scattered through trapped gas bubbles. 

His Russian scientific team had finally accomplished its elusive goal: retrieving the purest sample yet from Lake Vostok, an Antarctic body of water that has likely been locked beneath thousands of feet of ice for up to 15 million years. They are now testing that frozen water — which comes from a place Lipenkov says is unlike “any other environment on our planet” — for signs of life.

For years, teams of scientists in the Antarctic have plotted to drill into the continent’s vast subglacial lakes, hoping to find life that has been isolated for eons. They have faced many challenges, including weather delays and equipment breakdowns. 

A drill finally penetrated through the ice to Vostok’s waters in February 2012, and samples were obtained from water that froze on the drill. In March 2013, biologist Sergey Bulat of the Petersburg Nuclear Physics Institute announced that this ice hosted a new form of bacterial DNA, but his claim was disputed because the sample was contaminated with kerosene drilling fluid.

Lipenkov, on the same team but from the Arctic and Antarctic Research Institute in St. Petersburg, hopes the cleaner water obtained this year will settle the controversy. And ongoing analysis of the new sample’s air bubbles could confirm a tantalizing theory: According to Lipenkov, Vostok may hold 50 times as much oxygen per gallon as seawater — a level toxic to most life. 

“If there is microbial life in the lake, it should be something unusual,” says Lipenkov. High levels of oxygen likely accumulated in the lake over millions of years as glacial ice melted, injecting trapped gases from air bubbles into its waters.

Real Life

January 2013 also brought another milestone: An American team penetrated 2,600 feet of ice to reach Lake Whillans, another subglacial lake in Antarctica. Scientists there were able to begin analyzing the lake water as soon as a sample was lifted out of the borehole. 

Within hours, they found bacterial cells, more than 450,000 per teaspoon. Deprived of sunlight, some of these bacteria may instead eat iron and sulfur minerals generated as glaciers grind up the bedrock, says Jill Mikucki, a microbiologist at the University of Tennessee in Knoxville who helped sample the lake.

Life forms in Whillans and Vostok could help researchers understand what kind of life might survive on other worlds. Subglacial lakes provide earthly analogs of ice-covered oceans deep beneath the surface of moons orbiting Jupiter and Saturn. 

By discovering what kind of life inhabits Antarctic lakes, John Priscu — a microbial ecologist at Montana State University in Bozeman who is analyzing samples from Lake Whillans — hopes to understand what sort of technology will be needed when probes are eventually sent to those frozen moons. In Lake Whillans, says Priscu, “we have an excellent model to draw a fairly strong hypothesis of what [life] we might find in another icy world.” 

Earth's Biggest Volcano Discovered

On the floor of the Pacific Ocean lies a giant that has been sleeping for 145 million years.



The Pacific Ocean floor hosts Earth’s largest volcano — Tamu Massif, at 120,000 square miles.

William Sager’s 20-year hunch has paid off in a very big way.

In September, the University of Houston geophysicist and his team announcedthat Tamu Massif, an underwater volcano about a third of the way from Japan to Hawaii, is by far the largest volcano on the planet.

For two decades, using sonar and other undersea mapping methods, Sager has been studying an oceanic plateau in the northwestern Pacific called Shatsky Rise. Over several expeditions, he began to suspect that the subtly dome-shaped formation at Shatsky’s south end, which he named Tamu Massif, might be an enormous volcano.

To confirm his theory, Sager’s team drilled core samples and bounced seismic waves through Tamu’s layers to determine its composition. They discovered Tamu’s 120,000 square miles were made of massive lava sheets, up to 75 feet thick, that had erupted from a single summit about 145 million years ago.

In square miles, Tamu Massif is larger than Arizona. Its single summit dwarfs multi-volcano complexes, also known as composite volcanoes, on Hawaii and Iceland. With 75 percent of the volume of Mars’ gigantic Olympus Mons, Tamu ranks as the second-largest known volcano in the solar system.

Sager believes it’s possible that we may one day find even greater volcanic giants beneath the waves. For now, however, he is savoring a sweet moment 20 years in the making. 

“As scientists, we spend our lives doing research,” says Sager. “We get maybe one moment when we can make people look up from their smartphones and be reminded of the wonder in the world.”

Amplituhedron May Shape the Future of Physics

This multidimensional shape can simplify certain quantum equations — and possibly also revolutionize physics.

Physicists have long struggled to understand exactly what happens after subatomic particles collide. For decades, the best tool involved basic sketches (called Feynman diagrams) of each possible result. For all but the simplest scenarios, this method fills pages with drawings and equations. 

A new computational insight in 2004 dramatically reduced the amount of paper required to describe a collision, and these new formulas combined multitudes of Feynman diagrams into a single mess of math. Last year, Princeton physicist Nima Arkani-Hamed was analyzing the formulas in search of a better way to simplify these quantum calculations. Using only pen and paper, he discovered a new kind of geometric shape called an amplituhedron — one that hints at a new way of seeing the universe.

Arkani-Hamed noticed the formula could be rearranged and still yield the same answer. Like paleontologists brushing away dirt to reveal a fossil, he and his colleagues found the pieces of a shape within the math — pieces that together form a multidimensional amplituhedron. The shape’s dimensions — length, width, height and other parameters (hence “multidimensional”) — represent information about the colliding particles, and the equation describing its volume also describes the particles that emerge from the collision. 

This result, the volume, is a single term that fits on a space the size of a napkin.

Unlike the older methods for exploring particle collisions, the amplituhedron is not rooted in a world where a particle starts in one place and time before moving to the next location and moment. That is, the shape does not exist in space-time — it does not rely on a conception of the universe that theoretical physicists suspect might be incorrect. (When they try to knit together large-scale and small-scale forces, such as gravity and those that hold atoms together, the assumption of space-time leads to mathematical inconsistencies, a clue that something’s amiss with current assumptions about the universe.) 

“We’ve known for decades that space-time is doomed,” says Arkani-Hamed. “We know it is not there in the next version of physics.” Though the collisions described by the amplituhedron still occur in space-time, the object itself is outside it, providing a possible way to imagine a world not woven of this fabric.

The new shape is intriguing, says physicist Lance Dixon, a pioneer in the field of particle collisions, but he cautions that so far it can only describe particle collisions within a simplified version of quantum theory — the results don’t yet translate to the real world. Arkani-Hamed acknowledges it is a “baby example”; he calls it “step zero” in the journey to create a new kind of physics — a project on par with the discovery of the probabilistic particle collisions themselves. 

For now, the amplituhedron offers a hint of what this strange new world could look like.

For years, health professionals have been urging better nutrition and more exercise for children. Are we finally listening?

TOP 100 STORIES OF 2013

#9	Childhood Obesity Reversed

For years, health professionals have been urging better nutrition and more exercise for children. Are we finally listening?

By Jeff Wheelwright|Tuesday, January 07, 2014

RELATED TAGS: OBESITY, FAMILY HEALTH

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Public health officials call it an epidemic. The American Medical Association calls it a disease. During the past 30 years, obesity rates in the U.S. have more than doubled among adults (to 35 percent) and tripled among children and adolescents (to 17 percent). The problem seemed unstoppable — until this year. 

For the first time in decades, reported the Centers for Disease Control and Prevention (CDC), obesity rates declined among low-income preschool children, a particularly vulnerable demographic group. No magic diet was involved: This public health success seems to be the result of promoting healthier foods and physical activity. 

Between 2008 and 2011, the CDC measured the weights and heights of about 12 million children between the ages of 2 and 4 in 40 states, two territories and the District of Columbia. The preschoolers were on the rolls of federal nutrition programs, including the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), which provides dietary counseling and food vouchers to low-income mothers. 

In 18 states, obesity rates declined slightly. Three states showed increases; the remaining 19 had no change from the prior survey. 

This small change could have big benefits down the road. Young children’s weight predicts their future health, says epidemiologist Ashleigh May, the lead author of the CDC report: “If they’re obese at this age, they’re five times as likely to become obese as adults.” Overweight children can develop high blood pressure and high blood sugar, which raises their risk of cardiovascular disease and diabetes when they grow up.

Four years ago, WIC revised its list of approved groceries to emphasize fruits and vegetables — one possible cause for the turnaround. More women are now breast-feeding, and breast-fed babies are more likely to be at a healthy weight. 

The CDC also credits public awareness programs like “Let’s Move,” championed by first lady Michelle Obama, that promote healthy eating and exercise in day care centers and among child care providers. “We were expecting spotty progress, but this [decline] was widespread,” Let’s Move Executive Director Sam Kass says.

A White House task force calls for childhood obesity rates to fall to 5 percent by 2030. Is it a reasonable goal? 

“All the public health campaigns in this country required concerted efforts over many years,” says pediatrician David Ludwig, director of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital. He cites drives to reduce traffic fatalities and curb tobacco use. “We have every reason to hope for an eventual
victory.”

Extracting Family Trees From Ancient Genomes

New techniques and very old bones overcome the limits of genome sequencing for prehistoric horses, ancient cave bears, and even our own early ancestors.

For millennia, the stories of long-extinct species — including our own progenitors — have been buried with their skeletal remains. But in 2013, ultramodern DNA extraction and sequencing techniques enabled researchers to access ancient genetic codes and translate their evolutionary tales: Researchers in Denmark reconstructed a record-breaking 700,000-year-old horse genome, and geneticists in Germany began parsing the DNA of 400,000-year-old hominids.

Geologists saw the first glint of the horse’s history in 2003 when they plucked its toe bone from permafrost in a remote Yukon gold mine. The uninterrupted freeze of the permafrost preserved DNA in the horse bone, but since DNA decays into smaller and less intelligible fragments over time, the specimen seemed too ancient to analyze. “When that fossil was found, no one would have believed that we could get DNA out of it,” says Yukon government paleontologist Grant Zazula.

Armed with a decade of improvements in next-generation sequencing techniques, Denmark-based evolutionary geneticist Ludovic Orlando could finally piece together what was left of the bone’s DNA. Using what’s called true single molecule sequencing, Orlando lit up the A’s, C’s, T’s and G’s, one by one, to assemble the horse’s genome — six times older than any nuclear DNA specimen ever sequenced.

The results, published in July, radically revise the timeline for equine evolution, revealing that the common ancestor of contemporary horses, zebras and donkeys originated at least 4 million years ago, twice as far back
as previously thought.

Hunting for Human History

Deciphering human DNA of the same vintage seems like it should be next on the docket. Here’s the catch: No comparably ancient human skeleton has been found preserved in permafrost. Weathered hominid bones — and their decaying DNA — are generally discovered in temperate caves, like the one in Spain’s Atapuerca Mountains, whose collection of these remains is among the world’s largest and oldest. “This is a dream site for studying the ancestors of Neanderthals and perhaps modern humans,” says evolutionary geneticist Svante Pääbo.

But getting a DNA sample from a bone means drilling a hole in it, and archaeologists were not about to let geneticists go to work on the deteriorating human skeletons without some guarantee of a genome. So Pääbo’s team procured a similarly degraded non-human specimen from the same rocky dwelling for their proof of concept, published in August: the genome of a 400,000-year-old cave bear.

The Germany-based team developed two advances to get and use more of the bear’s genetic information from its bones. First, they salvaged DNA fragments degraded down to as few as 30 base pairs (by comparison, fragments from the frozen horse bone averaged 78 base pairs). Second, they separated the complementary strands of DNA in these fragments before sequencing so they could still use one half of the double helix even if the other half were damaged.

Now Pääbo’s team is applying these techniques to Atapuerca’s ancient hominids to pinpoint changes in the human genome and determine when they occurred. “If we can see things directly — things that were alive 400,000 years ago,” says Jesse Dabney, a doctoral student involved with the project, “we can get a clearer picture of our own evolution.”

Two Elusive Prime Number Problems Solved

After centuries of flummoxing number crunchers, two mathematical puzzles about prime numbers were cracked this year.

Prime numbers — those divisible only by 1 and the number itself, like 5, 11 or 37 — are like the atoms of mathematics: All numbers are formed by multiplying these building blocks together. 

But what happens when you add a number to a prime number? When will the sum be prime? Or, conversely, when is a number a sum of primes? Mathematicians have been working to answer these fundamental questions for centuries, and on the same day in May, two mathematicians finally found tantalizing partial answers to both of them.

To imagine the answer to the first question, start by adding the number 2 to a prime. When the sum is also prime, the pair is called a “twin prime,” like 5 and 7. As numbers get bigger, primes become more rare; you might then expect the spacing between them to grow consistently larger, too, so that very large twin primes would never occur.

Yet the famous but unproven “twin prime conjecture” states there are an infinite number of primes that differ by 2 — no matter how high you count, you will never run out of twin primes. A related, more general conjecture suggests there are also infinitely many pairs of primes that differ by 4, or 6, or any even number at all. 

But conjecture is all it was until May 13, when a nearly unknown mathematician, Yitang Zhang of the University of New Hampshire, made a serious dent in the twin primes conjecture. During a talk at Harvard, he presented a proof of the related, general conjecture that as prime numbers increase toward infinity, the spaces between them — counterintuitively — do not always do the same: No matter how big prime numbers get, you’ll always find pairs of them that differ by, at the very most, 70 million. 

Admittedly, 70 million is a lot bigger than 2, so the twin primes conjecture remains unsolved. But Zhang established for the first time a necessary (and supremely difficult) first step — that the spread between successive primes does not increase toward infinity.

On the same day Zhang emerged from obscurity to reveal his stunning proof, Harald Helfgott of the Ecole Normale Superieure in Paris cracked another famously elusive problem involving prime numbers — a variation on the Goldbach conjecture, which claims that every even number greater than 2 is the sum of two primes. (For example: 16 = 5 + 11.) 

Instead, Helfgott posted a proof of the “odd Goldbach conjecture,” which states that every odd number above 5 is the sum of three primes. (19 = 3 + 5 + 11.) It’s a big step in the right direction because the full Goldbach conjecture implies the odd version: Just take your odd number (say, 19), subtract the prime number 3 (now you have 16), and apply the Goldbach conjecture to the resulting even number. (16 = 5 + 11.)

While Helfgott’s proof does not solve the full conjecture, which is considered much harder, it shines a light on the intricate dance prime numbers engage in. Now the full conjecture, along with Zhang’s almost-but-not-quite-proven twin primes conjecture, remain a tantalizing plum for future mathematicians

Voyager 1 Goes Interstellar

More than three decades after it left our planet, Voyager 1 entered a realm where no Earthborn spacecraft has gone before.

It took more than 35 years and a journey over 15 billion miles, but: “Voyager 1 is the first human-made object to make it into interstellar space — we’re actually out there,” says Don Gurnett, lead author of a September Science paper announcingthe feat. 

The probe first gained fame in the 1970s and ’80s with visits to the solar system’s outer planets; it’s been racing toward this next milestone ever since. In recent years, various scientists had prematurely trumpeted Voyager 1’s crossing into interstellar space, the area dominated by gas ejected from other stars. This time, however, NASA’s scientists are sure, thanks to three key pieces of evidence — two of which were published earlier in 2013. 

First, astronomers announced that Voyager 1 had recorded a steep drop in the “solar wind,” a stream of charged particles emanating from the sun. At the same time, the spacecraft also detected a corresponding uptick in galactic cosmic rays, ultrafast particles that come from outside the solar system. 

This waning of the solar wind amid growing gusts from interstellar space suggested Voyager 1 had crossed the edge of the heliosphere, the bubble of charged particles blown by our sun that surrounds the solar system. At the bubble’s edge, the expansion of the sun’s hot, ionized gas, or plasma, is halted by the pressure of cooler, denser plasma in the space between the stars.

But that wasn’t enough to prove that Voyager 1 had sailed through the heliosphere; knowing for sure required determining the density of plasma bathing the spacecraft. Alas, Voyager 1’s plasma sensor failed back in 1980, near Saturn. Fortunately, it still has a working plasma wave instrument, which measures the frequency of plasma vibrations (as opposed to the density). All the instrument needed was something to set the surrounding sea of plasma in motion.

A lucky explosion on the sun fit the bill: When this blast of charged, magnetic particles reached Voyager 1 in April, the instrument detected these vibrations and revealed the plasma to be more than 40 times denser than previously measured in the heliosphere. Combined with previous data, this was consistent with an escape into interstellar space at the same time as the measured drop in the solar wind.

“It all really fits,” says Gurnett. “That’s why we’re so confident this is the answer.”

Voyager 1 has enough power in its nuclear generator to send dispatches until the mid-2020s. Beyond that, its momentum will carry this most distant and devoted scout silently toward the stars, a testament to humanity’s will to explore.

Scientists Make Progress in Growing Organs From Stem Cells

Liver buds and brain organoids are among this year's life-saving advances in growing spare human parts.

Liver Buds to the Rescue

Some 16,000 ailing Americans are waiting to receive a liver transplant. But due to a shortage of viable livers, it’s likely that fewer than 7,000 transplants will be performed in 2013. In Japan, where the shortage is worse, the number of people in need of new livers is 10 times as great as the number of deceased donors who could provide one. 

That gap motivated stem cell biologist Takanori Takebe and his colleagues at the Department of Regenerative Medicine at Yokohama City University in Japan to find an alternate solution. This year they succeeded in generating mini-livers, or liver buds, from stem cells that were taken from human skin and reprogrammed to an embryonic state. (Embryonic stem cells are notable because they can morph into virtually any cell type in the body.) 

When mixed with two other types of cells, the fabricated primitive liver cells organized themselves into three-dimensional structures, complete with blood vessels. In effect, Takebe’s team re-created the process by which a human embryo begins to form a functioning liver. 

Transplanted into a mouse, the human liver buds, about 5 millimeters long, exhibited many functions of the mature organ, such as metabolizing sugars and drugs. When the scientists disabled the mouse’s own liver, the human buds kept the animal alive for two months. A person with liver failure would require an infusion of “tens of thousands” of liver buds, Takebe says. 

Until the buds can be generated from the skin of each individual patient, recipients will have to rely on immune-suppressing drugs to avoid rejection, just as they would with the transplant of an entire organ. Replacement liver buds might be available to human patients in a decade or less. — Jeff Wheelwright

Growing Brain Organoids

Scientists can’t yet grow spare parts of the human brain to fix neurological injuries or defects, but they have recently used stem cells to create brain organoids, formations of cells that mimic some of the brain’s regions. A team led by neuroscientist Jürgen Knoblich of Austria’s Institute of Molecular Biotechnology developed the organoids to help them simulate disease. 

Two types of stem cells were used to produce the mini-brains: embryonic cells and adult cells that had been reprogrammed to a starter state. The cells were put into a special culture and then suspended in a gel and stimulated by nutrients, all geared to turn them into neurons like those found in the cortex. 

The neurons literally “self-organized,” according to Knoblich, and after several weeks formed three-dimensional structures about one-tenth of an inch in diameter.

“If you zoom out and look at the whole, it’s not a brain,” Knoblich says. “But our cultures contain individual brain regions that have a functional relationship with one another.” Besides the dorsal cortex, researchers were able to grow, among other regions, parts of the ventral forebrain, which makes neurons that connect to the cortex, and the choroid plexus, which generates spinal fluid. 

In their most impressive experiment, the scientists derived organoids from the skin cells of a person affected by microcephaly. This genetic disorder causes a drastic reduction in brain size and stature. The microcephalic organoids were smaller than the organoids grown from healthy people, apparently because the patient’s stem cells had divided too early and became depleted. 

“What our organoids are good for is to model the development of the brain and to study anything that causes a defect in development,” Knoblich says. For example, by taking neural stem cells from a patient with schizophrenia, researchers might turn back the clock and track the onset of the condition in an organoid. Knowing how schizophrenia starts might help prevent it. — Jeff Wheelwright

Human Stem Cells Made From Eggs

It was 1996 when biologists first fused a mammalian skin cell with an egg cell, cloning Dolly the sheep. That was the start of the race to make a human embryo the same way. The method, called somatic cell nuclear transfer (SCNT), replaces the DNA in an egg cell’s nucleus with the genetic material from the nucleus of a skin cell, then tricks the egg cell to start dividing as if it had been fertilized with sperm. 

The result: an embryo that is an almost perfect genetic copy of the skin cell donor. In humans, the goal of SCNT is “nonreproductive cloning” — making embryos, then removing stem cells from the embryo and cultivating them to grow into tissues that could cure diseases, replace organs and heal injuries.

But getting eggs to act like embryos turned out to be far more difficult in humans than in sheep. It wasn’t until 2013 that Shoukhrat Mitalipov of the Oregon Health and Science University finally made SCNT work in humans, through careful tweaking and fine-tuning based on experiments with more than 1,000 rhesus monkey eggs. His final protocol requires a few dozen steps. 

“It’s a very complex procedure,” he says. Among Mitalipov’s secrets: stimulating reprogramming activity by priming the eggs with caffeine and by precisely dosing them with chemicals that coil and uncoil DNA’s twisted strands, and applying a gentle electric jolt to get the egg to begin dividing. (An embryo created this way will not develop into a fetus.) 

There are now other methods to make stem cells, but those made via SCNT have unique value because they are genetic copies of the living person who donated the skin cells (other methods either use foreign cells or involve genetic reprogramming). Thus, replacement tissues made from them shouldn’t trigger the immune system rejection that dooms many transplants. 

Making purpose-built tissues may be far in the future, because figuring out the exact recipes to turn cells into functioning bone, heart or spinal cord will take time. But Mitalipov’s triumph has big near-term benefits in giving researchers a new tool to understand all the details of how stem cells grow, divide and differentiate, says Larry Goldstein, director of the University of California San Diego Stem Cell Program: “It’s great science.” — Kat McGowan

Edward Snowden, the NSA, and the Never-Ending End of Privacy

The unprecedented government surveillance that surfaced in the summer brought the perennial clash between technology and privacy to a new level.

Samuel Warren and Louis Brandeis, writing in the Harvard Law Review, expressed concern over privacy infringements threatened by new technology: “Recent inventions and business methods call attention to the next step which must be taken for the protection of the person, and for securing to the individual . . . the right ‘to be let alone,’ ” they wrote. 

The year was 1890, and the inventions Warren and Brandeis cited were “instantaneous photographs” and devices for “reproducing scenes or sounds.” Those innovations now sound quaint, but the concerns they raised are fresher than ever. 

In 2013, former National Security Agency contractor Edward Snowden created an international firestorm when he leaked top-secret documents detailing the U.S. government’s surveillance activities. In addition to providing details on foreign eavesdropping of private citizens and leaders, the government effort has included PRISM, a massive data surveillance program that gathers Internet communications from open sources and a variety of private companies to track people’s connections. 

Americans still have legal protection for their most private communications — what they say and write to other American citizens — but how important is that protection in light of the government’s vast ability to collect data about almost every aspect of people’s daily activities?

As the scope of Snowden’s revelations expands by the day, the picture looks increasingly ominous: The NSA collects records of phone calls going back years. It patrols Internet cloud services. Your Facebook chats, your Skype calls, your Gmail messages can all be monitored.

The ironies are rich. Warren and Brandeis fretted over a shutterbug snapping pictures of an unsuspecting woman, while Sprint’s recent iPhone 5 commercial touts a “billion roaming photojournalists uploading the human experience.”

The introduction of Google Glass, the wearable computer with a head-mounted display that lets users record everything, may make personal surveillance nearly ubiquitous.

Technology has long driven fears. In the mid-1970s, Congress held a hearing to discuss ARPANET, a Pentagon project that some considered a frightening assault on privacy because it could create vast files on individuals by networking computers. Those concerns were soon eclipsed by public support for ARPANET’s successor: the Internet.

In 2002, the Pentagon took heat over the Total Information Awareness program, which New York Times columnist William Safire called a “supersnoop’s dream” that would create a “computerized dossier on your private life” based traffic and has access to most of the major email, chat and on commercial and government information. 

When the program was canceled, the public largely lost interest despite reports that it merely moved to the covert world. But while data mining a decade ago was concerned about cross-matching, say, travel reservations with immigration records, what Snowden revealed in 2013 was something far more ambitious. 

The documents demonstrated the NSA can and often does decrypt, hack and access almost any device or service used by private citizens.

What has enabled the government’s increasing ability to monitor our lives is not exotic spy technology but commercial technology embraced by Americans. We upload pictures to Instagram, provide information about friends and family to Facebook and store private letters on Gmail.

Even those who don’t broadcast their thoughts on Twitter provide reams of data mopped up by commercial companies. News read online is logged, purchases are tracked, and website visits are recorded. 

There is, thanks to the spread of Internet access and smartphones, more information on our daily lives than could have been imagined even a decade ago: We Google our aches and pains and stalk our former lovers, leaving a virtual trail of our daily movements simply by carrying a cell phone.

That data, recorded by commercial companies — be they cell phone and Internet service providers or your favorite social media — can be intercepted, hacked or secretly requested by the government. People may think they have control over personal information by, say, disabling location services on an app, but that’s not always the case, says Kalev Leetaru, a fellow in residence at Georgetown University and an expert in big data. 

“We never really think about it with a cell phone,” says Leetaru, pointing to the ability to trace a user’s location by tracking cell towers, essentially “leaving digital bread crumbs wherever you go.”

Today’s surveillance issues emerge from a clash of technology and policy. Companies encourage us to store our music, pictures and email in the cloud, but most people aren’t aware of what this means for privacy. A letter sitting in your home is covered by the Fourth Amendment protection against unreasonable search and seizure, but that same letter in your Gmail, if sent and read over six months ago, is not afforded the same protection.

Similarly, even when the content of our communication is protected by law, Snowden has demonstrated that metadata — the who, what, where and when of communications, encoded in our messages, calls and online activity — is fair game. 

The NSA may not be allowed by law to listen to your call to a friend, but the government can collect information about how many times you called that friend, how long the calls lasted and on which dates. And then they can use data mining to cross-match the relationship to your friend’s friends, essentially tracking your entire social network, like an involuntary version of Facebook.

One of the problems, says Paul Rosenzweig, a former Department of Homeland Security official and expert in data mining issues, is that people focus on content — what they actually say on the phone or in an email. What Snowden has brought to public debate is that as technology has expanded the amount of metadata being generated, the debate itself may need to change. 

“Metadata is more robust and detailed than content,” says Rosenzweig. “It may be we’re reaching a point where metadata is content. That would be a very big sea change.”

Carbon Dioxide Hits 400 ppm — Does It Matter?

In May, the amount of CO2 in our atmosphere crossed this long-hyped threshold, setting off a storm of media coverage. But how significant is the milestone?

On May 9, instruments atop Hawaii’s Mauna Loa volcano pegged the atmospheric concentration of carbon dioxide (CO2) — the gas that contributes most to global warming — at slightly above 400 parts per million (ppm). 

Pieter Tans, senior scientist with the National Oceanic and Atmospheric Administration (NOAA), and his colleague Ralph Keeling, director of the CO2 program at the Scripps Institution of Oceanography, had been watching the concentration climb ever closer to 400 ppm — a level not seen in millennia. 

They realized that reaching such a big, round number was “an opportunity to remind the world that CO2 is rising fast, and that the rate of rise in the last decade has been the fastest recorded,” Tans says. They also knew that “the press was looking over our shoulders, and of course they were going to announce it.”

So Tans and Keeling decided to get the word out first, by issuing a pair of press releases on May 10. Journalists jumped on it, calling 400 ppm a “grim” and “long-feared” milestone.

But was it?

National Ocean and Atmospheric Administration

Global warming became big news for the first time during the hot summer of 1988 when now-retired NASA climate scientist James Hansen testified before Congress that the trend was not part of natural climate variation, but rather the result of emissions of CO2 and other greenhouse gasses from human activities. By that point we had already passed 350 ppm. 

So in spring 2013, the approach of 400 ppm seemed like a significant, new threshold — the first one we’ve reached since climate change started making headlines regularly. But it is both an artificial and fuzzy symbol. Nothing fundamental actually changed in Earth’s climate system when we hit it. 

“It’s not that different from 390 or 410,” Tans points out. And even as the instruments in Hawaii indicated that we had reached the milestone, the global average concentration of CO2 was a few points lower. That’s because Hawaii is in the Northern Hemisphere, where most CO2 from fossil fuel burning comes from. 

To make things even fuzzier, the CO2 concentration in Hawaii quickly dipped below 400 ppm as plants greened during the Northern Hemisphere’s growing season, soaking up CO2 through photosynthesis. 

Over the long term, CO2 will continue to increase, bringing growing risks from sea level rise and disruptions to weather patterns. But it will take a couple of years — until about 2016, Tans estimates — for annual global-average CO2 levels to surpass 400 ppm.

For James White, a paleoclimatologist at the University of Colorado, 400 ppm is “a mile marker you pass on the interstate while flying by at 60 mph.” And he expresses few doubts about the road ahead. “We’re blowing the doors off 400.” He would not be surprised if we get to 800. “That will be the next big milestone, and that’s a fundamentally different world.” 

Over centuries, that amount of atmospheric CO2 could cause enough warming to melt all ice on land and bring the sea level up by 80 meters — enough to submerge Bangladesh and almost all of Florida.

New Signs of Long-Gone Life on Mars

A spectacular nail-biter of a landing was just the beginning. This was the year Mars’ rover Curiosity proved its worth by giving researchers unprecedented access to the Red Planet.



Curiosity looks back at the walls of Gale Crater in this colorized view.

In 1976, the Viking spacecraft gave us the first clear picture of the Martian surface — and sparked hopes that the barren, toxic planet once hosted life. In 2013, the rover Curiosity found the most convincing evidence yet that the planet was once habitable, as well as clues about why life there might have died out.

The $2.5 billion rover, roughly the size of a Mini Cooper automobile, discovered an ancient streambed soon after landing — evidence that water once flowed there. Next, Curiosity used its considerable payload of geologic tools to dig up further proof. 

Its robotic arm drilled a 2.5-inch borehole in mudstone bedrock. The robot fed the resulting rock powder into its Sample Analysis at Mars (SAM) instrument, which heated the sample, vaporizing it into gases that the tool could analyze.

Meanwhile, the Chemistry and Mineralogy (CheMin) tool beamed X-rays at the powder. The scattering of the rays reveals crystal structures, making it possible to identify Martian minerals.

The findings: carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorous — key ingredients for life — plus chemicals such as sulfur dioxide and hydrogen sulfide that could provide energy for microorganisms. All were found in a locale that was once wet, and neither too salty nor too acidic.

“To tie that all up in one ball of twine: We found a habitable environment,” says John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology.

Nonetheless, the rover found no sign of methane in the atmosphere, dashing hopes that methane-producing microbes might still dwell there now. By sampling other atmospheric gases, Curiosity also found one reason why life-friendly conditions vanished. 

Compared to the raw materials found elsewhere in the solar system (a record preserved in the sun and the gaseous planets Jupiter, Saturn, Uranus and Neptune) the Martian atmosphere has more heavy isotopes — heavier versions of basic elements such as carbon and oxygen. The skewed ratio suggests that the planet’s lighter isotopes escaped as part of a gaseous atmosphere and left a disproportionate amount of the heavy ones behind. 

The rover’s journey also collected evidence that a manned mission to Mars would require better shielding to safeguard the crew. The spacecraft carrying Curiosity found that with today’s propulsion and shielding technology, Mars-bound astronauts would be exposed every five or six days to as much radiation as a whole-body CT scan, a total of about 662 millisieverts by the end of the yearlong round-trip journey. This figure is beyond safety guidelines and enough to raise lifetime cancer risk by as much as 3 percent.

NASA is testing out new lightweight, durable shielding materials such as one made with hydrogen-filled nanotubes. Unlike larger atoms, when hydrogen is hit by cosmic rays it does not break down into showers of secondary particles that bombard astronauts with additional radiation.

Curiosity is now trekking toward the 3.4-mile-high Mount Sharp, where exposed rock layers that have preserved billions of years of geologic history may reveal more secrets about the Red Planet’s past. The rover should cover the five rugged miles in about a year. “Right now, it’s pedal to the metal,” says Grotzinger.

Russian Forces Double Along Ukraine Border

American officials are worried that 50,000 Russian troops being massed near the Ukraine border and within Crimea, the pro-Russian peninsula recently annexed by President Vladimir Putin, aren't there for just a training exercise

Despite Russian reassurances that Moscow’s troop buildup along Ukraine’s eastern frontier is for a military exercise, its growing scale is making U.S. officials nervous about its ultimate aim.

President Barack Obama on Friday urged Russia to stop “intimidating” Ukraine and to pull its troops back to “de-escalate the situation.” He told CBS that the troop buildup may “be an effort to intimidate Ukraine, or it may be that [Russia has] additional plans.”

Pentagon officials say they believe there could be close to 50,000 Russian troops bordering the former Soviet republic and inside Crimea, recently seized and annexed by Moscow. That estimate is double earlier assessments, and means Russian President Vladimir Putin could order a lighting strike into Ukrainian territory with the forces already in place. The higher troop count was first reported by the Wall Street Journal.

“We continue to see the Russian military reinforce units on their side of the border with Ukraine to the south and to the east of Ukraine,” Rear Admiral John Kirby, the Pentagon spokesman, said Thursday. “They continue to reinforce and it continues to be unclear exactly what the intent there is.”

State Department spokeswoman Marie Harf played down the notion that there are as many as 100,000 Russian troops now bordering Ukraine, as Olexander Motsyk, the Ukrainian ambassador to the U.S., said Thursday on Capitol Hill. “I hadn’t actually seen the hundred-thousand number,” Harf said. “There are huge numbers of Russian troops on the Ukrainian border. … We are concerned about Russia taking further escalatory steps with whatever number of tens of thousands of troops they have there, and have called on them not to do so.”

Washington got those assurances that the Russian troop buildup was only an exercise from Russian Defense Minister Sergei Shoigu a week ago. But no one in the U.S. government knows if Putin agrees—or if the Russian leader has changed his mind as the West has debated what level of economic and political sanctions might be imposed if Moscow takes an additional chunk of Ukraine beyond Crimea. “They made it clear that their intent was to do exercises and not to cross the border,” Kirby said. “Our expectation is they’re going to live up to that word.”

There is no plan to involve the U.S. military in what is happening in Ukraine, even if Russia takes more territory. Ukraine borders Russia, and Ukraine does not belong to NATO, where an attack on one member is deemed to be an attack on all.

“Should the Russians continue to move aggressively in that region and in the Ukraine, what does that mean—and NATO would have to respond, for example—what would that mean for the United States Army?” Rep. Tim Ryan, D-Ohio, asked the Army’s top officer Thursday.

“My responsibility is to make sure that the U.S. Army is prepared to respond as part of a joint force, as part of NATO,” General Ray Odierno, the Army chief of staff, responded. “So what I’m focused on is improving our readiness in combat, combat service support and combat aviation capabilities to make sure we’re ready to respond whether it’s from a humanitarian assistance aspect or any other aspect.”

How many of the 67,000 U.S. troops in Europe might be involved? “I simply don’t know,” Odierno said. “And I would just remind people that, actually, some of the soldiers that are assigned to Europe actually right now are in Afghanistan.”

Lawmakers suggested that the world is abandoning Ukraine. “It appears to me Ukraine was left defenseless over the last two decades,” said Rep. Marcy Kaptur, D-Ohio.

“Ukraine has stood with us both in Iraq and Afghanistan,” added Rep. Rodney Frelinghuysen, R-N.J. “We’re highly appreciative and recognize their sacrifice.”

The U.S. has made plain it is not rushing military aid of any kind to Ukraine, despite Kiev’s requests. Ukraine has sought lethal military aid—small arms and ammunition—but that is off the table. “The rations, the Meals Ready to Eat, they are on the way,” Kirby said. “We expect them to arrive in Ukraine probably by the weekend is the best estimate. They’re going over land.”

Obama stressed Thursday that economic and political sanctions would be the primary weapons the international community would be brandishing to curb Russian aggression against Ukraine. “I’ve been very clear in saying that we are going to do everything we can to support Ukraine and the Ukrainian people,” he said in Rome. “But I think that it’s also important for us not to promise and then not be able to deliver.”

The Navy SEALS’ Dying Words

Monday, August 6 marks the first anniversary of the Afghan crash of a U.S. military CH-47 Chinook helicopter that killed 30 Americans, including 17Navy SEALS. It was the worst single loss-of-life day for the U.S. in the war in Afghanistan. It was also the worst in the history of Naval Special Warfare.

Just six weeks before the crash, I spent several days meeting with members of the Navy’s elite SEAL Team SIX, talking to them about the loss of one of their teammates, Adam Brown, who had been killed in action during an especially complex raid on a compound in Afghanistan.

I met with two of them in a crowded bar in a remote Alaskan village. The salmon run had just begun so the place was packed with fishermen, one of whom approached our group with a tray of shot glasses overflowing with whiskey. It was also a place that SEALs would come to before heading for training exercises in the surrounding mountains.

The man offered to buy a round. “I’d be honored if we could have a drink together, to thank you all for your service. And for taking care of business in Pakistan,” he said. Tom Ratzlaff, one of the SEALs I was with, took two shots and handed one to me. “This is for Adam,” he clicked his glass against mine, I nodded, and we threw them back together.

Tom, who was better known as “Rat,” and Chris Campbell shared memories of their teammate, but as they talked about his life and the circumstances surrounding his death, they alluded to the fact that they were keenly aware death might be just around the corner, quite literally, for them too. They were about to be redeployed, and with the loss of Adam weighing heavily on their minds, there was some urgency to have a chance to talk and honor their brother-in-arms.

Kevin Houston, one of the SEALs I met with in Virginia Beach the following week acknowledged, “I could end up getting killed on my next mission I go on, but until that happens, for me, business will continue to be conducted.”

One of things I was most interested in understanding from these men was how they managed moving so fluidly between their family lives and their work as highly-trained warriors. Frequently, they were deployed, came home, and then were suddenly redeployed.

In some cases they developed rituals. Tom shared that whenever he boarded a helicopter for a mission, he said the Lord’s Prayer silently, once he got seated, and then prayed for protection. “I don’t ask for protection myself because that’s in his hands. I ask him to look after my wife and kids. Then I ask him to protect all my buddies and forgive them of all their sins and me of my sins. Then I move straight into thinking about what I’m about to do-the target, the map study, making sure I know which way’s north so I can call out things correctly on the target.”

During my interview with Heath Robinson, another teammate of Adam Brown’s, I asked “How do you do it?” referring to how they transition from lethal missions—shooting and killing people—and then coming back home, sometimes just hours later. Heath answered using his friend’s horses as an analogy. “His wife and daughter have horses,” said Heath. “Nothing makes [them] happier. Well, horses are dirty animals, every weekend he puts on his waders, goes in the barn, and shovels the manure…the dirty hay…their piss. It’s not a good job, it’s miserable, but somebody has to shovel the shit so the family can enjoy what they have.”

Kelley Brown, Adam’s wife, recalled the one time she saw “that side” of her husband. He had just returned home and was relaxing in a bubble bath when a very unlucky burglar attempted to break into their house. Adam, naked but covered in bubbles, flew out of the tub and the look in his eyes was someone she did not recognize. Moments later, the intruder bolted in fear and Adam returned to being her loving husband and the adoring father of their two young children.

The SEALs were also circumspect about death in a way that only those confronted with it regularly can be.

“I either want to die in combat, doing my job right now, or live till I’m 98 years old and see my great, great grand kids,” one of them told me. “I don’t want anything in between. None of us do. A warrior’s death, you can’t get any higher than that. It’s horrible for the family, they don’t want to hear that, but for us, the guys at our command, we’re okay with it. That is our duty, the highest calling. And if that happens to you, you hope you are in the right frame of mind that you are okay with it. I have seen a lot of people go, not well. Had they been able to do another take on it, they would probably want it to go better. I remember everything else about Adam also, but I will always remember the end. You know, your first impression lasts a relationship, and your last impression is with you forever. Adam died well.”

Six weeks after my last interview, I was returning to civilization from my version of being off the grid: camping with my family. My own happy grubby kids were in the back seat of our car when my cell phone indicated I had voicemail.

I called in and listened to one message after another and I learned that all seven of the men I had interviewed — John, Kevin, Brian, Heath, Matt, Tom, and Chris — had been killed in action the day before.

The team had been on a mission in the Wardak Province of Afghanistan, part of an operation intended to capture or kill leaders from an insurgent cell that was holed up in the region. The Chinook carrying them, along with 23 other Americans, and eight Afghan troops, had crashed and exploded after a single rocket propelled grenade struck its aft rotor blade.

Questions surrounded the crash: Why were so many from our most elite military unit on one helo? The most credible view is that it was a lucky shot, but some speculated that it might have somehow been retaliation at the same unit that had only a couple months earlier taken out Bin Laden.

As of today, some family members remain unsatisfied with the investigation. A few days after the crash, I attended Kevin Houston’s funeral, then began transcribing the interviews, haunted as I listened to their voices and read their reflections on life and on death.

As they had talked about Adam Brown, they had unknowingly defined themselves: humble, selfless, and fearless.

With the one-year anniversary of that tragedy upon us, I think of them, and their families, often.

My mind wanders to the inside of that helicopter, envisioning their final moments. It’s a dark place filled with questions — mainly the questions I didn’t ask when I interviewed each of them just weeks before they were killed — but the one thing I know for certain is that they died honorably: serving their country, doing what they believed in.

I have no doubt that they died well.