TIME Research

See How What Makes Us Happy Has Changed Over the Past 80 Years

Man jumping in mid air on beach
Daniel Ingold—Cultura RF/Getty Images

These days we consider good humor and leisure time to be crucial to our happiness

Psychologists from the University of Bolton in the U.K. have re-created a famous study conducted in the same town almost eight decades ago that sought to find out what made people happy.

In 1938, an advert was placed in the local paper asking readers “What is happiness?” reports Science Daily. After rating the importance of 10 factors from 226 people, researchers found that people believed security, knowledge and religion were the most important aspects of happiness.

Last year, Sandie McHugh and Professor Jerome Carson repeated the social experiment and found that while security was still in the top three, good humor and leisure came in poll position.

Meanwhile, religion, which was the third most important factor in 1938, has fallen to the bottom of the current list. In 1938, most people said they were happiest at home in Bolton, whereas today 63% said they were happier away from the town.

One factor that hasn’t changed, though, is the importance people place on luck — 40% believed good fortune was vital to their happiness both back then and in 2014. And in both eras, most people said they didn’t think happiness was related to material possessions and wealth.

“The overall impression from the correspondence in 1938 is that happiness factors were rooted in everyday lives at home and within the community,” said McHugh. “In 2014, many comments value family and friends, with good humor and leisure time also ranked highly.”

[Science Daily]

Read next: 7 Easy Happiness Boosters According to Harvard Research

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TIME animals

Gigantic Whales Eat Huge Amounts Thanks to ‘Bungee-Cord’ Nerves

Humpback whale breaches 3 miles off of Rockaway Beach on August 31, 2014 in New York City
Artie Raslich—Getty Images Humpback whale breaches 3 miles off of Rockaway Beach on August 31, 2014 in New York City

The discovery was an accident

Rorqual whales (blue, fin, humpback among others) are not only the world’s largest animals but when they eat they open their mouths to such an extent that they are capable of ingesting a volume of water larger than their own bodies. On Monday, scientists from the University of British Columbia explained how they do this — stretchy nerves.

“These large nerves actually stretch and recoil like bungee cords,” A. Wayne Vogl, an author of the study to be published in May in the journal Current Biology, said in a press release.

Normally, a firm collagen wall surrounds nerves and if stretched they become damaged. For example, humans can suffer from “nerve stretch injury.”

In rorqual whales, the nerves are packed into a centralized core surrounded by limber “elastin fibers.” When the whale opens its mouth the design enables the nerve fibers to unfold. The feeding whale will then gulp-up floating prey before the nerve snaps back and the sea water is filtered through baleen plates in its mouth, leaving behind a massive quantity of small prey.

What’s more, the discovery was an accident. A team member picked up what he believed to have been a blood vessel and stretched it. But upon closer examination the researchers realized that the blood vessel was in actuality a nerve.

The scientists plan to keep studying the whales in the hopes to better understand the folding and unfolding process.

TIME psychology

Why Dzhokhar Tsarnaev Cried in Court

HORIZONTAL Dzhokhar Tsarnaev, a suspect in the Boston Marathon bombing, photo released on April 19, 2013.
FBI/Getty Images Dzhokhar Tsarnaev, a suspect in the Boston Marathon bombing, photo released on April 19, 2013.

Jeffrey Kluger is Editor at Large for TIME.

When bravado does battle with the brain, the brain will win

Savagery is harder than you think. As members of a highly social species, genetically coded for cooperation, compassion, and the powerful, nearly telepathic ability to experience what another person is feeling, we should not be terribly surprised that convicted Boston Marathon bomber Dzhokhar Tsarnaev shed at least a few tears in court on Monday when his aunt took the stand in the trial’s penalty phase to plead for his life.

We like to think that our criminal monsters are just that—monstrous, somehow fundamentally different from the rest of us. And in some cases that’s true: serial killer Ted Bundy is often described as sociopathic, a man incapable of empathy. Movie theater shooter James Holmes is thought to be schizophrenic, a disease that can indeed leave people incapable of feeling.

But most of the time killers are people with the same emotional software as the rest of us. And just as happens with real software, theirs got corrupted somehow. When it comes to empathy, such a breakdown takes some doing.

The human brain is wired with so-called mirror neurons, brain cells that draw us together by causing us to experience similar things at the same moment. It’s mirror neurons that explain why yawns are contagious, why a newscaster’s sudden laughing jag makes you laugh too, why newborns—who have never seen themselves in a mirror and thus have no idea what their faces look like—will open their mouths wide when an adult does. Up to 10% of the brain’s neurons are thought to have mirroring properties, which is a measure of how important they are.

When Tsarnaev’s aunt took the stand, she began crying before she even spoke. When she did speak, she could manage to give only her name, her age and her place of birth before dissolving entirely and being allowed to step down. She was seated only 10 feet from her nephew, which made her a real and tactile presence.

Tsarnaev’s cool indifference, which has been on display throughout the trial, has seemed at least partly 21-year-old bravado—magnified many times over by whatever psychological journey he took that allowed him to commit the horrific crime he did, and magnified still more by the certain knowledge that his life is over, that he will either be executed or spend the next half dozen or so decades in a cage. It pays, at least in public, to maintain a certain numbness in the face of that reality, lest it become overwhelming.

But for a man-child who may be a horror but is not a Bundy, there are limits. Another person’s tears are limits. An aunt who, in a different time and place, would surely hug you is a limit. And mirror neurons—which populate the brain of the bomber as surely as they do the brain of the doctor or the mother or the person you love—are limits too. Tsarnaev ran out of emotional room today, and the sorrow he felt is just a small part of a penalty he will pay for many years.

Read next: Boston Bomber’s Teacher Says Tsarnaev ‘Always Wanted to Do the Right Thing’

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TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME psychology

Sympathy (of a Sort) for Aaron Hernandez

Goodbye to all that: Hernandez being arrested on June 25, 2013—his final day as a free man
George Rizer for The Boston Globe Goodbye to all that: Hernandez being arrested on June 25, 2013—his final day as a free man

Jeffrey Kluger is Editor at Large for TIME.

How should a civilized society punish its monsters?

Aaron Hernandez belongs in hell—literally. If the fiery pit really exists, the former New England Patriot who was just sentenced to life without parole for the murder of a friend, is awaiting trial for two earlier murders and is being sued by man whom he allegedly shot in the eye and left for dead, deserves a confirmed reservation in the lowest circle. What Hernandez and a lot of people like him don’t deserve, however, are the prisons in which they are serving their much-deserved sentences—at least in the conditions under which they will serve them.

The news stories that followed Hernandez’s conviction adhered to schadenfreudean form: watch as the man who used to wear number 81 dons the uniform of inmate W106228; watch as the one-time owner of a 7,100 sq. ft. home is locked inside a cell smaller than a parking space. There’s a certain understandable satisfaction in that: Criminal justice is at least partly about retribution—civil society venting its anger at its most uncivil members. And a killer like Hernandez has a lot of anger coming to him. But when does a lot become too much, especially if civil is the way a society wants to remain?

Just how Hernandez will do his lifetime of time is not yet set; a lot will depend on his behavior, his safety, and how much humbling the administrators of the Souza-Baranowski Correctional Center outside of Boston believe he needs. But at best he can expect to remain inside his cell 19 hours out of every 24. Solitary confinement is a possibility—and that will mean 23-hour-a-day lockdown with an hour outside in a small, caged recreation area. He will eat his meals alone in his cell.

If Hernandez does wind up so deep in the correctional hole, he won’t be alone. Roughly 2.3 million people are incarcerated in the U.S. and an estimated 80,000 of them are either in solitary confinement or some other kind of segregated housing. That includes the more than 3,000 inmates on death row, most of whom remain there for years or decades. That once included too the 151 inmates who have been released from death row since 1973 after wrongful convictions were exposed and overturned. In many states, 23 hours in the cell also means no TV, radio, books, music, magazines, or any other distractions.

Conditions like that may be designed to break the spirit, especially in the case of gang members or other violent prisoners, but they also wreck the mind—and fast. As TIME reported in 2007, electroencephalograms show that it takes only a handful of days in isolation for prisoners’ brain waves to shift to a pattern indicating isolation and delirium. As long ago as 1890, the U.S. Supreme Court condemned solitary confinement for its tendency to leave prisoners in a “semi-fatuous condition,” a form of punishment some investigators now call “no-touch torture.”

Suicide rates are disproportionately high among the punitively entombed, as are hallucinations, violent episodes, panic, paranoia, and self-mutilation. And since it is underlying mental disorders that often land inmates in prison in the first place, the time they spend in the hole only exacerbates the problem.

Not only is this inhumane, it also perverts the criminal justice system. When Jose Padilla, the so-called dirty bomber now serving 21 years on terrorism charges, was preparing to stand trial in 2007, his lawyers challenged his fitness to do so, arguing that the three and a half years he had spent in solitary had rendered him unable to assist in his own defense. It was an argument that availed Padilla little, but it provides a credible avenue for other defense attorneys involved in similar cases.

Worse, inmates who are not serving life terms and are eventually released to the streets after long stretches in segregated confinement are likelier to re-offend violently—a combination of rage and lack of social contact destroying whatever self-regulatory faculties they once had. In 2013, Colorado prison director Tom Clements, who had begun reforming the state’s solitary confinement policies, was gunned down by a former prisoner who went straight from solitary confinement to freedom, a sudden trip across dimensions he was clearly not able to handle. His successor, Rick Raemisch, has continued the reforms and even spent nearly 24 hours in an isolation cell as a way of both sampling the experience and demonstrating his commitment to limiting its use.

Pressure for reform is coming as well from prison staffs—who live every day with the dangers that accrue when violent criminals are driven systematically mad. Last year, the Texas prison guards’ union wrote a letter to the state’s department of criminal justice asking that the use solitary confinement be curbed, that even some death row inmates be integrated into the prison population and that such sanity-preserving privileges as TVs, tablets, and the option of a prison job be more widely offered.

According to the Houston Chronicle, the state had already made impressive progress, reducing the solitary confinement population by 25% since 2006. But that still leaves 7,100 inmates—2,400 of whom have diagnosed with psychiatric illnesses or mental disability—locked away alone. A handful of other states including New York, Colorado, and Mississippi have also begun reforming their solitary confinement policies.

Compassion for monsters is not easy to achieve—and the slope gets slippery fast. Hernandez is one thing, but what about Boston Marathon bomber Dzhokhar Tsarnaev, who is still waiting to see if he will be sentenced to death or life? What about Oklahoma City bomber Terry Nichols or 9/11 conspirator Zacarias Moussaoui? Your pure evil may be different from my pure evil, so how do we decide? The only thing all of these criminals have in common is that they once had lives, freedom, and, in the case of Hernandez, fame and great wealth too—and they forfeited it all. We can punish them and pen them without forfeiting an important part of ourselves as well.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME animals

Elephants, Rhinos and Other Large Plant-Eaters Face Extinction, Study Says

Elephant Rhino
Getty Images Tshukudu Game Reserve, South Africa.

Scientists see a bleak future for large herbivores

The world’s largest plant-eating animals like elephants and rhinoceroses are facing dramatic population losses due to poaching and resource destruction, with 60% of large herbivores threatened by extinction, according to a new study.

Grass-grazing giants like elephants, hippopotamuses and black rhinoceroses only occupy a tiny fraction of their historical ranges, according to the study in Science Advances, and the loss of herbivores over 100kg (220lb) is likely result in “enormous ecological and social costs.”

The loss of large herbivores has been endemic in Africa for years, but the study sheds new light on the widespread loss of large animals due to over hunting for meat—some one billion people rely on wild meat for subsistence.

Hunting and land-use changes have a devastating effect on those species, with habitat loss due to deforestation and meat hunting having a particularly negative effect. The number of forest elephants in central Africa declined by 62% between 2002 and 2011, and some 100,000 elephants were poached between 2010 and 2012.

Poaching continues to harm large grazers, particularly rhinos. “This slaughter is driven by the high retail price of rhinoceros horn, which exceeds, per unit weight, that of gold, diamonds, or cocaine,” the study said.

Slowing deforestation and over-hunting, and halting poaching, will be crucial to ensure the large grazers don’t go extinct. “Solving the current crisis associated with poaching for meat and body parts is an essential step, although one that is extremely challenging,” the authors write.

TIME A Year In Space

Here’s How Coffee Cups in Space Could Help Save Lives on Earth

Six Space Cups as delivered to NASA January, 2015 for the Capillary Effects of Drinking in the Microgravity Environment (Capillary Beverage) investigation.
Image courtesy of Andrew Wollman/NASA Six Space Cups as delivered to NASA January, 2015 for the Capillary Effects of Drinking in the Microgravity Environment (Capillary Beverage) investigation.

The so-called Space Cups can reveal much about fluid physics

Astronauts aboard the International Space Station can now enjoy a much-needed hot cup of joe with their very own espresso machine and six specially designed microgravity coffee cups.

But NASA says these Space Cups will do a lot more than lift espresso to an astronaut’s lips. They will also provide scientists with data on how complex fluids (such as coffee or tea with sugar) move in zero gravity, writes Mark Weislogel, professor at Portland State University and former senior aerospace engineer for NASA working on microgravity fluid physics.

MORE: See the Trailer for TIME’s Unprecedented New Series: A Year in Space

Before the invention of the Space Cup, astronauts would have a drink by sucking liquid out of a bag. The new coffee cups (which are transparent 3-D-printed jugs) have a sharp inner corner that allows the liquid to be pushed along the inside of the cup — a process called capillary flow — towards the drinker’s lips.

By experimenting with capillary fluid physics in small containers like cups, scientists believe it will help them build better and safer advanced fluid systems that are relied on in space, including oxygen supply, water coolants, air conditioners, toilets and fuel and recycling systems.

But NASA says the data collected in the study can also be applied to fluid systems on earth, like improving portable medical diagnostic devices used to quickly test blood for infectious diseases in remote areas of the world.

TIME psychology

How Birth Order Will Shape the New Royal Princess

It's never easy being a second-born—especially when your big brother is going to be king

Dear Royal Princess:

You’re having some kind of week—what with labor and birth and the entire planet waiting for pictures of you so they can smile and swoon and make strange smoochy noises at the mere sight of you. It’s all good, and the last thing I want to be is the skunk at the monarchical picnic, but there’s one detail folks may have neglected to mention and you might as well learn about it now. His name is George—or Georgie as all those smoochy people call him—and he’s got plans for you.

George is your big brother. He’s only 20 months old and the world finds him adorable, but you won’t—for a lot of reasons. For starters, at some point in your childhood he will sit on your head. Actually, at a lot of points in your childhood he will sit on your head—and there is absolutely nothing you can do about it.

The main problem with George is not that he’s third in line to the throne and you’re fourth. That just happens to be one of the downsides of your family business. The problem is one that’s familiar to the rest of us serfs and colonists: he’s the first born, and you’re not.

Your mom and your dad—lovely people, by all accounts—are no different from other parents when it comes to baby-making; they’re ruled by their genes and genes are greedy. The only thing they want is to be reproduced over and over and over again. That makes moms and dads want to have lots of babies, which is good, but they don’t treat all those babies exactly the same.

The first-born—Georgie in your case—gets a head start on food, attention, medical care, education and more. Before the second-born—you, in your case—even comes along, that makes the big sibling a better bet to survive childhood, grow up and have babies of his own, which makes the genes smile. In your family, of course, there’s plenty of food, money and other resources to go around, but back in the days of one of your many royal grandpas—let’s say Edward III, who had the rotten luck to be in office in 1348 when the black plague was making its rounds—surviving childhood wasn’t such a sure thing.

So moms and dads, who have already invested a lot of resources in the first born, tend to favor that child, with later ones getting what’s left over. Corporations call this sunk costs (you’ll learn about this at Eton). In the case of the monarchy, it’s called “an heir and a spare”—but you didn’t hear that from me.

This is an arrangement that suits that first product just fine, which is why big brothers and sisters tend to play by the rules. Your job—and the job of any littler royals who may come along after you—will be to try to upset that order. It’s why later-borns tend to be more rebellious and to take more risks than first-borns. You’ll be likelier to play extreme sports than big bro George. Even if you and he play the same sports, you’ll choose a more physical position—say, a catcher instead of a pitcher in baseball (which is a sport like cricket except the bat is thinner and the ball moves faster and there’s this thing called the infield fly rule and…never mind). In the event you ever become Ruler of the United Kingdom of Great Britain and Northern Ireland and of other Realms and Territories around the world—and a whole lot would have to go wrong in your family for that to happen, so don’t start getting measured for the cape yet—you’d be a more liberal, less conventional monarch than your big bro will be.

Later-borns are more inclined to be artists too, and if there is a comedian in the family, it’s likeliest to be the very last-born. This makes sense, since when you’re the smallest person in the nursery, you are in constant risk of getting clocked by someone bigger, so you learn to disarm with humor.

As you get older, other perils await—ones that are especially problematic for royal families. You don’t really know your grandpa Charles yet, but you’ll find he’s a pretty well-behaved guy (OK, there was the thing with grandmum Camilla, but that’s for him to explain to you). The same is true of your dad. How come? Because they’re both going to be king one day.

As for your Uncle Harry? Ask him about what he wears to Halloween parties (not good) or to play pool in Las Vegas hotel rooms (not much). And if he hasn’t always been the picture of royal reserve, well, neither have your great-grandpa Phillip or your great uncle Andrew. (One day, ask Uncle Andy about a special friend of his named Miss Stark—and if you really want to get a laugh, call her Auntie Koo.) That’s what comes from having lots of money, too much free time, and being really, really close to the throne but never getting to sit on it.

In fairness, it’s not just you royals who get up to mischief when a big sib is the star and you’re not. Something similar has happened here in the colonies. Ever heard of Donald Nixon or Billy Carter or Roger Clinton or Neil Bush? Probably not, but trust me, don’t be those guys.

None of this is for you to worry about yet. Even royal babies are just babies, so for now sleep in, fatten up and hang with mom as much as you can—especially if it keeps your dad away from her. Trust me, the middle-child gig is even worse.

TIME A Year In Space

The Great Space Twins Study Begins

Astronaut twins Mark and Scott Kelly
Marco Grob for TIME Astronaut twins Mark and Scott Kelly

Scott and Mark Kelly—one in space, one on Earth—go under the microscope for science

When serendipity hands scientists the perfect experiment, they don’t hesitate to jump on it. That’s surely the case with NASA’s improbable study of Scott Kelly, who has just completed the first month of a one-year stay aboard the International Space Station, and his identical twin brother Mark, who will spend the same year on Earth.

Zero-gravity messes with the human body in all manner of ways but it’s not always easy to determine which problems are actually caused by the weightlessness and which would have happened anyway. The puzzle gets a lot easier if you just happen to have a second subject with exactly the same genes, the same lifestyle and the same level of fitness. Observe any differences in their health over the year, subtract the matching genetics and what’s left over on the other side of the equal sign is likely the work of weightlessness. Much of the research that will investigate these differences in the Kellys is already underway, both in space and on the ground.

One of the most important studies involves what are known as telomeres, the cuffs that protect the tips of chromosomes in much the way a plastic aglet protects the tips of shoelaces. The longer we live, the shorter our telomeres get, and the unraveling of the chromosomes that results drives the infirmities that come with age.

“One of the things that comes up almost all the time in the interviews with Mark and Scott is this idea of the twin paradox,” says Susan Bailey, of Colorado State University, who is coordinating the telomere research. “Is the space twin going to come back younger than the Earth twin?” That kind of time dilation happens in movies like Interstellar, but only when someone is moving at close to light speed. The year Scott will spend orbiting Earth at 17,500 mph (28,000 k/h), may indeed slow his body clock, but by barely a few milliseconds. His telomeres, however, will more than make up for that, and he’ll likely come home physically older than Mark.

“A whole variety of life stresses have been associated with accelerated telomere loss as we age,” says Bailey. “You can imagine strapping yourself to a rocket and living in space for a year is a very stressful event.”

Chromosomal samples from both Kelly twins were taken and banked before Scott left to provide a telomere baseline, and more samples will be collected over the year. Mark’s are easy enough to get ahold of, but Scott will have to draw his own blood in space, spin it down and freeze it, then send it home aboard returning ships carrying cargo or astronauts. Both twins will also be followed for two years after Scott comes back to determine if any space-related telomere loss slows and if the brothers move closer to synchrony again.

The twins’ blood samples will also be used to look for the state of their epigenomes, the chemical on-off switches that sit atop the genome and regulate which genes are expressed and which are silenced. Environment is a huge driver in epigenetic changes, especially in space, as cells adjust to the unfamiliar state of weightlessness. “We can kind of build these molecular maps of what’s happening in the different cells…as they’re challenged by this low gravity condition,” says geneticist Chris Mason of Weill Cornell Medical Center in New York City, who is leading this part of the work.

Also due for a good close look are Scott’s and Mark’s microbiomes. The number of cells that make up your body are actually outnumbered 10 to one by the bacteria, viruses, yeasts and molds that live in your body. It’s only the fact that most of them are also much smaller than human cells that prevents them from outweighing you 10 to one as well. Still, if you could extract them all and hold them in your hand they’d make a hot bolus of alien organisms weighing up to 5 pounds.

This is actually a good thing, since we need this interior ecosystem to keep our bodies—especially our digestive tract—running smoothly. Like so much else for Scott, that will change in space. “A significant part of what’s present normally in the gastrointestinal tract doesn’t actually colonize,” says research professor Martha Vitaterna of Northwestern University, co-investigator on the microbiome work. “These are things that are constantly being reintroduced with fresh fruits and vegetables, and that’s missing from Scott’s diet.”

Genes can also make a difference to the microbiome, since any individual’s genetic make-up may determine which microorganisms thrive in the gut and which don’t. Scott’s and Mark’s microbiomes will be compared throughout the year, principally through stool samples—ensuring some unglamorous if scientifically essential shipments coming down from space.

Other studies will involve the way body fluids shift in zero-g, drifting upwards to the head and elsewhere since there is no gravity pulling them down. This can damage vision as a result of pressure on the eyeballs and optic nerve. It can also lead to damage to the cardiovascular system, with astronauts returning to Earth at increased risk of atherosclerosis.

Some of these changes can be tracked by blood studies, which will look for proteins that regulate water excretion. Ultrasound scans can also look for vascular damage. Before leaving Earth, Scott had a few small dots tattooed on his upper body to indicate the exact points at which he has to position the ultrasound probe—easier than taking precise measurements to find the proper spots every time he’s due for a scan.

Multiple other studies will be conducted on the twins as well, looking at their immune systems, sleep cycles, psychological states and more. For years, space planners have been talking a good game about going to Mars one day, but those trips will last more than two years. We know the hardware can survive the trip; what we don’t know is if the human cargo can. A year from now—thanks to the Kellys—we’ll be a lot smarter.

TIME is covering Kelly’s mission in the new series, A Year In Space. Watch the trailer here.

TIME Sports

Pacquiao, Mayweather, and the Physics of Getting Punched in the Head

Enjoy it now, guys: Mayweather (left) and Pacquiao are heading for a brain pounding
JOHN GURZINSKI; AFP/Getty Images Enjoy it now, guys: Mayweather (left) and Pacquiao are heading for a pounding

A prize fight might be thrilling but it's murder on the brain

In a perfect world, a highly trained, heavily muscled man would not punch you in the head.

Fortunately for most of us, the world is indeed perfect in that one small way. But most of us aren’t boxers. For those who are–say, Floyd Mayweather Jr. and Manny Pacquiao, who square off this weekend in a matchup dubbed “the fight of the century“—getting punched in the head by highly trained men is an occupational hazard. The payday can be huge, but the price—in terms of traumatic brain injury—can be very high.

Plenty of sports are hard on the brain. Organized football, from Pop Warner up through the pros, has been rightly pilloried for the devastating toll it takes on players, who suffer from repeated concussions that may lead to chronic traumatic encephalopathy (CTE), the degenerative condition that has claimed so many NFL veterans.

But while football might be the most concussive team sport, it’s followed closely by ice hockey, and then by soccer, lacrosse, basketball, field hockey, gymnastics and baseball, generally in that order, depending on age, gender and the level of professionalism of the players.

Even in football, however, blows to the head are incidental if unavoidable parts of the contest. In boxing, they are the contest—and that means trouble.

“[Boxing] is not really tracked the way school sports are tracked,” says Robert Cantu, clinical professor of neurology and neurosurgery at the Boston University school of medicine. “Concussions in boxing are a poorly reported sample, but at B.U. we’ve had a 100% incidence of CTE in the boxers we’ve studied.”

With good reason. Various studies have put the force delivered by a blow from a trained boxer at anywhere from 450 lbs. (204 kg) to over 1,400 lbs. (635 kg), enough to accelerate the head to 53 g’s. Those forces hit in one of two ways—linear and rotational—and neither of them is good.

“Acceleration from a straight-on punch is linear, while a roundhouse is more rotational,” says Dr. Christopher Giza, professor of pediatric neurology and neurosurgery at UCLA’s Mattel Children’s Hospital, and a former commissioner of the California State Athletic Association. “We think rotational forces are more important in getting knocked out, but most punches have components of both.”

Within the brain, it’s the white matter—or the fatty sheathing on nerve cells that serves as insulation and connective tissue—that suffers the most. “The brain has the consistency of firm Jell-O,” says Giza. “If you shake or twist it you put strain on the connections, leading to stretching or tearing.” That causes both immediate and long-term harm, with the damaged connective tissue leaking what are known as tau proteins, which build up over time to form the signature deposits that signal CTE.

The brain’s slightly loose fit in the skull causes other problems. A thin layer of fluid surrounding the brain is supposed to provides shock absorption in the case of minor blows, but when you get hit hard enough, that little bit of wiggle room allows the brain to rattle around, with soft tissue colliding with unyielding bone. That can cause shock, bruising and even bleeding and death.

In boxing, it’s often easy to see when either kind of damage has caused trauma. The knockout, or the dazed and disoriented condition known as a technical knockout, is practically the very definition of a severe concussion. But most concussive injuries produce subtler symptoms, and while sports like football and hockey are increasingly taking the time to examine players during games and sit them out if there are signs of trouble, that’s not an option in boxing.

“From the ringside, trainers have to examine players very briefly between rounds to determine if they should stop the fight,” says Giza. “They need a very specific set of skills to diagnose a problem so quickly.” With other things going on at the same time—cuts treated, strategy planned—that diagnosis becomes even harder. And since the sport hardly rewards a boxer whose trainer pulls him preemptively, there is a competitive and financial incentive in simply slugging on.

None of this means that all boxers will sustain traumatic brain injury. The 100% figure Cantu cites is derived, he readily acknowledges, from a self-selected population of fighters who come to his clinic seeking help for neurological symptoms. At least some of the larger population of boxers who don’t show up may be fine. What’s more, smart boxers—at least at the championship level—are increasingly taking steps to protect themselves, sparring less, engaging in safe aerobic training more and fighting perhaps only two bouts a year.

But limiting things to two well-compensated fights is a luxury not every boxer can afford. For too many of them—as well as too many athletes in other sports—the payday comes first and health comes second. It’s a way of doing business that growing numbers of athletes live to regret.

TIME space

This Was Messenger’s Goodbye Tweet Before It Crashed Into Mercury

"It is time to say goodbye"

NASA’s spacecraft Messenger just crashed into Mercury, and it sent two last tweets before self-destructing:

Messenger has been orbiting Mercury since 2011, and on Thursday it ran out of fuel and met its end. Other well-wishers have taken to Twitter to bid farewell to Messenger too:

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