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Top 10 Science Stories of 2015

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It’s been a busy year for scientists: medical breakthroughs; newly discovered human ancestors; genes and neurons; Earth’s troubled species; and enticing findings from Mars, Pluto, and beyond. Here are 10 science advances that made a big impact in 2015. 

1. WE GOT UP CLOSE AND PERSONAL WITH PLUTO.

After a 9.5-year, 3-billion-mile journey, NASA’s intrepid New Horizons spacecraft finally reached Pluto in July, sending back high-resolution images of the dwarf planet and its moon, Charon. At its closest approach, the craft passed within 7800 miles of Pluto’s surface—close enough to reveal bizarre ice mountains and vast, crater-free plains, seemingly divided into “cells” dozens of miles wide. There’s evidence of geological activity within the last 100 million years—a mere eye-blink compared to the age of the solar system—which came as a surprise to scientists, who imagined Pluto to be a geologically “dead” world. Charon, meanwhile, has cliffs that run for hundreds of miles, and canyons more than six miles deep. The findings will keep planetary scientists busy for years.

2. WE OPENED THE DOOR TO CUSTOM DNA.

An organism’s development is governed by its DNA—but what if you could manipulate that DNA at will? The era of custom “gene editing” now looms on the horizon, thanks to a tool known as CRISPR-Cas9, which allows researchers to “swap out” sections of a genome faster and more cheaply than ever before. Earlier this year, scientists developed gene-edited mosquitos that are resistant to malaria and gene-edited African pigs that are immune to swine fever; the FDA, meanwhile, recently approved a fast-growing, gene-edited salmon for human consumption.

Are genetically engineered humans next? Scientists in China have already done the first experiments on human embryos, in a bid to correct faulty genes that cause disease. The embryos in those studies were non-viable, but even so there’s been a storm of controversy. Some argue in favor of human gene modification, in the hope of engineering human beings with less susceptibility to devastating illnesses such as cancer and dementia—while others see any such research as the start of a slippery slope leading to a world divided between genetic haves and have-nots.

3. WE MAY HAVE FOUND A NEW MEMBER OF THE HUMAN FAMILY TREE.

Berger et al. ineLife.

Pieced together from 1500 bones found deep in a cave near Johannesburg, South Africa, Homo naledi—claimed to represent a new species of human ancestor—caused a sensation when the finding was announced in September. (“Naledi” means “star” in Sesotho, one of South Africa’s official languages.) Its bones tell a complicated story. The small skull and ape-like shoulders suggest it may be among the earliest members of the human family tree, while the shape of the feet and ankles indicate it walked upright. And yet the highly curved fingers hint at the tree-climbing prowess of its ancestors.

But is it really a new species? Some skeptics believe the bones could belong to early members of Homo erectus, a well-documented human ancestor that lived from about 1.9 million years ago to about 70,000 years ago—or even an isolated offshoot of Homo sapiens. It would help if we knew exactly when Homo naledi flourished; unfortunately, scientists haven’t been able to date the bones yet.

4. WE DISCOVERED THAT WE MAY BE CAUSING A SIXTH MASS EXTINCTION.

Over the past 450 million years, the Earth has witnessed five “mass extinction events”—catastrophes in which an asteroid impact or volcanic activity triggered rapid climatic change and a dramatic loss of biodiversity. The most severe of these was the event that killed off the dinosaurs—and three-quarters of all species—some 66 million years ago. Scientists believe we’re now on the brink of a sixth such mass extinction event—only this time, the culprit is human activity. In a study published in the journal Science Advances in June, biologists found that our planet is losing animal species at 20 to 100 times the average “background” rate, and that the rate is increasing. “The smoking gun in these extinctions is very obvious, and it’s in our hands,” Todd Palmer, a biologist at the University of Florida and a co-author of the study, told the Washington Post

5. WE PENETRATED THE BLOOD-BRAIN BARRIER FOR THE FIRST TIME.

Injecting drugs into the body is routine—unless you’re targeting the brain, which is protected by the “blood-brain barrier,” a film-like coating that surrounds the blood vessels in the brain. The barrier prevents harmful substances from entering the brain—but also stands in the way of certain treatments (for example, chemotherapy drugs targeting brain tumors). In November, doctors in Toronto used tightly focused ultrasound waves to penetrate the barrier for the first time. The technique could pave the way for the treatment of an array of illnesses, from brain cancer to Alzheimer’s disease. 

6. WE FOUND LIQUID WATER ON MARS.

Getty Images

Mars, with its many similarities to Earth, has long been the most enigmatic planet in our solar system—and it became even more beguiling in September, when NASA scientists announced that they’d found evidence for flowing water on the planet’s surface. Images from the Mars Reconnaissance Orbiter reveal dark streaks that appear during the Martian summer, likely the result of seasonal “flows.” A caveat: the water is briny and extremely salty, and scientists are far from certain that it’s capable of supporting life. And while it would be great to go there (or send a robotic ambassador) for a close-up view, there’s a very real danger of contaminating the area with microbes from Earth.

7. WE CONFIRMED THAT “SPOOKY ACTION AT A DISTANCE" IS REAL.

It’s one of the most bizarre features of the quantum world: The notion that two particles, even if they’re far apart, can be “entangled” quantum mechanically. When two particles are entangled, measuring the properties of one particle instantly gives you information about the other, regardless of the distance between them. The notion of entanglement dates back to a paper written by Einstein and two colleagues in the 1930s, although he later dismissed the idea as “spooky action at a distance.” But beginning in the late '70s, ever-more sophisticated experiments suggested entanglement is real. In October, physicists in the Netherlands managed to entangle two electrons almost a mile apart—and they say they’ve ruled out all of the loopholes which made earlier experiments inconclusive. And while it all may sound pie-in-the-sky, scientists say that the research could eventually lead to the development of ultra-fast “quantum computers,” with potentially game-changing applications in medicine, cryptography, and artificial intelligence.

8. WE IMPLANTED FALSE MEMORIES IN MICE.

iStock

We think of memories like pages in a scrapbook, or pictures in a photo album, but in practice, our memories are often wrong. “False memory syndrome” is now recognized as a real phenomenon in the scientific literature, and psychologists are eager to learn more about how erroneous memories form. Animal studies may shed some light. In March, neuroscientists in France described how they were able to implant false memories into mice while the animals slept. They used electrodes to directly stimulate specific nerve cells within the brain, causing the mice to associate certain locations with rewards. After waking, the mice “remembered” those associations, spending more time in the locations where they (incorrectly) recalled receiving a reward. The researchers hope their work will help explain how false beliefs form in humans.

9. WE THEORIZED THAT DARK MATTER WIPED OUT THE DINOSAURS.

We don’t usually think of events in deep space influencing life on Earth—after all, astrology was debunked centuries ago. But if physicist Lisa Randall is right, there may be a subtle but important connection between an exotic form of matter that permeates the universe, and the evolution of life on our blue-green world. In her book Dark Matter and the Dinosaurs, Randall suggests that a thin disk of dark matter—a kind of matter that responds to gravity, but not to light—might periodically perturb the orbit of comets at the far edges of our solar system. That might be what happened 66 million years ago, when a wayward comet is believed to have slammed into the Earth, triggering catastrophic climate change and dooming not only the dinosaurs but three-quarters of all species. It’s a controversial theory, but it could gain support, Randall says, if we can detect the gravitational influence of the alleged dark-matter disk. Read an excerpt from Dark Matter and the Dinosaurs on Science Friday.

10. WE FOUND A WEIRD STAR—OR MAYBE E.T.? (MAYBE NOT.)

Artist's representation of a crumbling Dyson sphere orbiting KIC 8462852. Image credit: Danielle Futselaar // SETI International

You wouldn’t think it’s anything special from its name—KIC 8462852—but the peculiar star, located about 1500 light-years from Earth, set the Internet abuzz in September when it was suggested that it might be home to an advanced alien civilization (“might” being the key word, of course). Data from the Kepler space telescope showed that the star undergoes strange variations in brightness over time. Kepler is specifically designed to detect planets that may periodically pass in front of a star, causing it to dim—but KIC 8462 displayed a more unusual pattern, with more substantial dimming at irregular intervals. A swarm of comets was said to be the most likely explanation. But one of the astronomers also suggested the possibility of an “alien megastructure”—perhaps some variation of the “Dyson sphere,” a vast artificial structure that an advanced civilization might build surrounding a star, popularized by physicist Freeman Dyson in the 1960s.

Later, radio astronomers aimed the Allen Telescope Array in California at the star, just in case it was emitting alien chatter. It was not. The latest thinking is that it’s probably comets after all. The lesson? When it’s a choice between aliens and something else, it’s always been something else (so far), and that’s most likely the case this time. But for getting people’s attention, little green men beat icy snowballs every time. 

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Cotswold Archaeology
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Stones, Bones, and Wrecks
Amateur Archaeologists in England Unearth Rare Roman Mosaic
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Cotswold Archaeology

For the past three years, amateur archaeologists and historians in southern England have been working side-by-side with volunteers to excavate several seemingly related local Roman sites. Now, just two weeks before the dig's scheduled conclusion, they've made a fantastic discovery: a rare 4th-century CE mosaic that is being hailed as "the most important of its type in Britain in more than half a century," according to The New York Times.

Dating to roughly 380 CE, the mosaic was unearthed near the village of Boxford in Berkshire. The project—which included a rotating assembly of 55 members—involved local interest groups like the Boxford History Project and the Berkshire Archaeological Research Group, and was overseen by Cotswold Archaeology, a company that helps builders preserve archaeological finds. Funding was provided by the Heritage Lottery Fund, which gives grants to heritage projects across the UK.

In the project's first two years, the group members discovered a large Roman villa, a bathhouse, and a farmstead. In 2017, they began excavating the main villa, a site that yielded pottery, jewelry, coins, and other ancient objects. None of these artifacts, however, were as spectacular as the mosaic, which volunteers unearthed in a moment of serendipity shortly before funding for the dig ended.

Revealed sections of the artwork depict scenes featuring Bellerophon, a mythological Greek hero, along with other fabled figures. Bellerophon is famous in legends for capturing the winged horse Pegasus and for defeating the Chimera, a fire-breathing creature with a lion's head, a goat's body, and a serpent's tail.

Citizen archaeologists in Boxford, England unearth a Roman mosaic thought to date from 380 CE.
Cotswold Archaeology

"The range and style of imagery is very rare in the UK, where simple geometric patterns are the norm," Duncan Coe, a principal heritage consultant with Cotswold Archaeology, tells Mental Floss. "The combination of artwork and inscriptions is unique in this country. The range of imagery is also unique, with at least two scenes from the story of Bellerophon, a character from Greek mythology, augmented by Hercules and the Centaur, Cupid and telamones [male statues used as a column]—and we only have half of the mosaic revealed so far."

Excavators uncovered nearly 20 feet of the mosaic, but ultimately reburied it to deter looters and prevent damage. Members of Boxford's local archaeological community hope to secure funding and return to the site—now dubbed the Boxford villa—to dig up the entire scene.

A Roman mosaic thought to date from 380 CE, unearthed by citizen archaeologists in Boxford England.
Cotswold Archaeology

In addition to teaching experts about the villa's owners—who were evidently sophisticated and wealthy—and Boxford's ancient heritage, the newly discovered mosaic isn't just any ordinary artwork, according to Coe: "This isn't just an isolated mosaic, but a small, but very important, part of a bigger jigsaw that advances our understanding of what was happening in southern England just before the Roman government abandoned Britain," he says.

[h/t The New York Times]

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15 Riveting Facts About Alan Turing
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More than six decades after his death, Alan Turing’s life remains a point of fascination, even for people who have no interest in his groundbreaking work in computer science. He has been the subject of a play and an opera, and referenced in multiple novels and numerous musical albums. The Benedict Cumberbatch film about his life, The Imitation Game, received eight Oscar nominations. But just who was he in real life? Here are 15 facts you should know about Alan Turing.

1. HE’S THE FATHER OF MODERN COMPUTER SCIENCE.

Turing essentially pioneered the idea of computer memory. In 1936, Turing published a seminal paper called “On Computable Numbers” [PDF], which The Washington Post has called “the founding document of the computer age.” In the philosophical article, he hypothesized that one day, we could build machines that could compute any problem that a human could, using 0s and 1s. Turing proposed single-task machines called Turing machines that would be capable of solving just one type of math problem, but a “universal computer” would be able to tackle any kind of problem thrown at it by storing instructional code in the computer’s memory. Turing’s ideas about memory storage and using a single machine to carry out all tasks laid the foundation for what would become the digital computer.

In 1945, while working for the UK’s National Physical Laboratory, he came up with the Automatic Computing Machine, the first digital computer with stored programs. Previous computers didn’t have electric memory storage, and had to be manually rewired to switch between different programs.

2. HE PLAYED A HUGE ROLE IN WINNING WORLD WAR II.

Turing began working at Bletchley Park, Britain’s secret headquarters for its codebreakers during World War II, in 1939. By one estimate, his work there may have cut the war short by up to two years. He’s credited with saving millions of lives.

Turing immediately got to work designing a codebreaking machine called the Bombe (an update of a previous Polish machine) with the help of his colleague Gordon Welchman. The Bombe shortened the steps required in decoding, and 200 of them were built for British use over the course of the war. They allowed codebreakers to decipher up to 4000 messages a day.

His greatest achievement was cracking the Enigma, a mechanical device used by the German army to encode secure messages. It proved nearly impossible to decrypt without the correct cipher, which the German forces changed every day. Turing worked to decipher German naval communications at a point when German U-boats were sinking ships carrying vital supplies across the Atlantic between Allied nations. In 1941, Turing and his team managed to decode the German Enigma messages, helping to steer Allied ships away from the German submarine attacks. In 1942, he traveled to the U.S. to help the Americans with their own codebreaking work.

3. HE BROKE THE RULES TO WRITE TO CHURCHILL.

Early on, Bletchley Park’s operations were hampered by a lack of resources, but pleas for better staffing were ignored by government officials. So, Alan Turing and several other codebreakers at Bletchley Park went over their heads to write directly to Prime Minister Winston Churchill. One of the codebreakers from Bletchley Park delivered the letter by hand in October 1941.

“Our reason for writing to you direct is that for months we have done everything that we possibly can through the normal channels, and that we despair of any early improvement without your intervention,” they wrote to Churchill [PDF]. “No doubt in the long run these particular requirements will be met, but meanwhile still more precious months will have been wasted, and as our needs are continually expanding we see little hope of ever being adequately staffed.”

In response, Churchill immediately fired off a missive to his chief of staff: “Make sure they have all they want on extreme priority and report to me that this had been done.”

4. HE HAD SOME ODD HABITS.

Like many geniuses, Turing was not without his eccentricities. He wore a gas mask while riding his bike to combat his allergies. Instead of fixing his bike’s faulty chain, he learned exactly when to dismount to secure it in place before it slipped off. He was known around Bletchley Park for chaining his tea mug to a radiator to prevent it from being taken by other staffers.

5. HE RODE HIS BIKE 60 MILES TO GET TO THE FIRST DAY OF SCHOOL.

Though he was considered an average student, Turing was dedicated enough to his schooling that when a general strike prevented him from taking the train to his first day at his new elite boarding school, the 14-year-old rode his bike the 62 miles instead.

6. HE TRIED OUT FOR THE OLYMPICS.

Turing started running as a schoolboy and continued throughout his life, regularly running the 31 miles between Cambridge and Ely while he was a fellow at King’s College. During World War II, he occasionally ran the 40 miles between London and Bletchley Park for meetings.

He almost became an Olympic athlete, too. He came in fifth place at a qualifying marathon for the 1948 Olympics with a 2-hour, 46-minute finish (11 minutes slower than the 1948 Olympic marathon winner). However, a leg injury held back his athletic ambitions that year.

Afterward, he continued running for the Walton Athletic Club, though, and served as its vice president. ”I have such a stressful job that the only way I can get it out of my mind is by running hard,” he once told the club’s secretary. “It's the only way I can get some release."

7. HE WAS PROSECUTED FOR BEING GAY.

In 1952, Turing was arrested after reporting a burglary in his home. In the course of the investigation, the police discovered Turing’s relationship with another man, Arnold Murray. Homosexual relationships were illegal in the UK at the time, and he was charged with “gross indecency.” He pled guilty on the advice of his lawyer, and opted to undergo chemical castration instead of serving time in jail.

8. THE GOVERNMENT ONLY RECENTLY APOLOGIZED FOR HIS CONVICTION …

In 2009, UK Prime Minister Gordon Brown issued a public apology to Turing on behalf of the British government. “Alan and the many thousands of other gay men who were convicted as he was convicted under homophobic laws were treated terribly,” Brown said. "This recognition of Alan's status as one of Britain's most famous victims of homophobia is another step towards equality and long overdue." Acknowledging Britain’s debt to Turing for his vital contributions to the war effort, he announced, “on behalf of the British government, and all those who live freely thanks to Alan's work I am very proud to say: we're sorry, you deserved so much better."

His conviction was not actually pardoned, though, until 2013, when he received a rare royal pardon from the Queen of England.

9. … AND NAMED A LAW AFTER HIM.

Turing was only one of the many men who suffered after being prosecuted for their homosexuality under 19th-century British indecency laws. Homosexuality was decriminalized in the UK in 1967, but the previous convictions were never overturned. Turing’s Law, which went into effect in 2017, posthumously pardoned men who had been convicted for having consensual gay sex before the repeal. According to one of the activists who campaigned for the mass pardons, around 15,000 of the 65,000 gay men convicted under the outdated law are still alive.

10. HE POISONED HIMSELF … MAYBE.

There is still a bit of mystery surrounding Turing’s death at the age of 41. Turing died of cyanide poisoning, in what is widely believed to have been a suicide. Turing’s life had been turned upside down by his arrest. He lost his job and his security clearance. By order of the court, he had to take hormones intended to “cure” his homosexuality, which caused him to grow breasts and made him impotent. But not everyone is convinced that he died by suicide.

In 2012, Jack Copeland, a Turing scholar, argued that the evidence used to declare Turing’s death a suicide in 1954 would not be sufficient to close the case today. The half-eaten apple by his bedside, thought to be the source of his poisoning, was never tested for cyanide. There was still a to-do list on his desk, and his friends told the coroner at the time that he had seemed in good spirits. Turing’s mother, in fact, maintained that he probably accidentally poisoned himself while experimenting with the chemical in his home laboratory. (He was known to taste chemicals while identifying them, and could be careless with safety precautions.)

That line of inquiry is far more tame than some others, including one author’s theory that he was murdered by the FBI to cover up information that would have been damaging to the U.S.

11. HIS FULL GENIUS WASN’T KNOWN IN HIS LIFETIME.

Alan Turing was a well-respected mathematician in his time, but his contemporaries didn’t know the full extent of his contributions to the world. Turing’s work breaking the Enigma machine remained classified long after his death, meaning that his contributions to the war effort and to mathematics were only partially known to the public during his lifetime. It wasn’t until the 1970s that his instrumental role in the Allies' World War II victory became public with the declassification of the Enigma story. The actual techniques Turing used to decrypt the messages weren’t declassified until 2013, when two of his papers from Bletchley Park were released to the British National Archives.

12. THE TURING TEST IS STILL USED TO MEASURE ARTIFICIAL INTELLIGENCE …

Can a machine fool a human into thinking they are chatting with another person? That’s the crux of the Turing test, an idea developed by Turing in 1950 regarding how to measure artificial intelligence. Turing argued in his paper “Computing Machinery and Intelligence” [PDF] that the idea of machines “thinking” is not a useful way to evaluate artificial intelligence. Instead, Turing suggests “the imitation game,” a way to assess how successfully a machine can imitate human behavior. The best measure of artificial intelligence, then, is whether or not a computer can convince a person that it is human.

13. … BUT SOME CONSIDER IT TO BE AN OUTDATED IDEA.

As technology has progressed, some feel the Turing test is no longer a useful way to measure artificial intelligence. It’s cool to think about computers being able to talk just like a person, but new technology is opening up avenues for computers to express intelligence in other, more useful ways. A robot’s intelligence isn’t necessarily defined by whether it can fake being human—self-driving cars or programs that can mimic sounds based on images might not pass the Turing test, but they certainly have intelligence.

14. HE CREATED THE FIRST COMPUTER CHESS PROGRAM.

Inspired by the chess champions he worked with at Bletchley Park, Alan Turing created an algorithm for an early version of computer chess—although at that time, there was no computer to try it out on. Created with paper and pencil, the Turochamp program was designed to think two moves ahead, picking out the best moves possible. In 2012, Russian chess grandmaster Garry Kasparov played against Turing’s algorithm, beating it in 16 moves. “I would compare it to an early caryou might laugh at them but it is still an incredible achievement," Kasparov said in a statement after the match-up.

15. THERE IS ALAN TURING MONOPOLY.

In 2012, Monopoly came out with an Alan Turing edition to celebrate the centennial of his birth. Turing had enjoyed playing Monopoly during his life, and the Turing-themed Monopoly edition was designed based on a hand-drawn board created in 1950 by his friend William Newman. Instead of hotels and houses, it featured huts and blocks inspired by Bletchley Park, and included never-before-published photos of Turing. (It’s hard to find, but there are still a few copies of the game on Amazon.)

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