Scientists have found one of the youngest exoplanets ever, huddling close to a star that is just 2 million years old. Located 450 light-years from Earth in the constellation Taurus, the star is so young that it still has its baby fat — it is surrounded by the disk of gas and dust from which it formed.

The planet, CI Tau b, is hefty for an infant — tipping the scales at 11 times the mass of Jupiter, say astronomer Christopher Johns-Krull of Rice University in Houston and colleagues in a paper posted May 25 on arXiv.org. It’s surprising, the researchers say, that such a large planet could have formed in just 2 million years — peanuts on cosmic timescales.
Such baby-faced exoplanets have been spotted before (SN: 12/26/15, p. 14), but they’ve lingered farther from their stars. This fledgling planet shows that such behemoths can form quickly and snuggle close to their stars. Scientists still don’t know whether star-hugging planets form far away and migrate inwards, or whether they are birthed close to their stars. The new planet could shed light on that process.

The scientists used a variety of optical and infrared telescopes to reveal periodic variations in the frequency of the star’s light, caused by the planet’s gravitational pull. CI Tau b tugs its star back and forth as it swings around in a tight orbit that it completes every nine days, the researchers determined. Hints of the planet showed up in both optical and infrared light, ruling out spurious signals caused by sunspots or other variability within the young and active star.

Editor’s note: Science News astronomy writer Christopher Crockett is a coauthor on the paper, which incorporates work he did as an astronomer at Lowell Observatory in Flagstaff, Ariz., prior to joining Science News.

The brains of human ancestors didn’t just grow bigger over evolutionary time. They also amped up their metabolism, demanding more energy for a given volume, a new study suggests.

Those increased energy demands might reflect changes in brain structure and organization as cognitive abilities increased, says physiologist Roger Seymour of the University of Adelaide in Australia, a coauthor of the report, published online August 31 in Royal Society Open Science.

Blood vessels passing through bones leave behind holes in skulls; bigger holes correspond to bigger blood vessels. And since larger vessels carry more blood, scientists can use hole size to estimate blood flow in extinct hominids’ brains. Blood flow in turn indicates how much energy the brain consumed. (In modern humans, the brain eats up 20 to 25 percent of the energy the body generates when at rest.)
Seymour and colleagues focused on the carotid arteries, the vessels that deliver the bulk of the brain’s blood. The team looked at nearly three dozen skulls from 12 hominid species from the last 3 million years, including Australopithecus africanus, Homo neanderthalensis and Homo erectus. In each, the researchers compared the brain’s overall volume with the diameter of the carotid artery’s tiny entrance hole at the base of the skull.
“We expected to find that the rate of blood flow was proportional to the brain size,” Seymour says. “But we found that wasn’t the case.” Instead, bigger brains required more blood flow per unit volume than smaller brains.
The boost in blood flow, and therefore metabolism, suggests two possible conclusions, Seymour says. As hominid brains got bigger, they might have packed in more nerve cells, or their nerve cells might have fired more frequently. Either way, he argues, the increased blood flow suggests greater brainpower, perhaps reflecting reorganization of the brain over the course of evolution.

But not all of the blood coming into the brain through the carotid arteries directly supports mental prowess. “You need more complicated wiring for bigger and more cognitively advanced brains,” says Dean Falk, an evolutionary anthropologist at Florida State University in Tallahassee. “But those brains have more advanced cooling requirements.”

Some of the blood coming in through the carotid arteries absorbs heat generated by the brain’s activity and then drains away, helping to keep the brain cool, Falk says. So while the study is a scientifically rigorous look at metabolism and blood flow toward the brain, she says, a follow-up study is needed to account for the blood moving away from the brain.

Lawrence David’s gut check gets personalA Jim Carrey movie inspired computational biologist Lawrence David to change the course of his research. As a graduate student, David saw Yes Man, a 2008 film in which Carrey’s character is forced to say yes to all propositions.

David thought the movie’s message about opening yourself to new experiences, even uncomfortable ones, might make science more exciting than it already was. “Only good things would happen if I loosened up and said yes to everything,” he says.

The next day, his graduate mentor at MIT, Eric Alm, was talking about the brand-new science of the human microbiome, the collection of bacteria, viruses and other microscopic organisms inhabiting the human body. What someone ought to do, Alm suggested, is sample a person’s feces every day for a year to see whether the microbiome changes. “I had just seen the movie, so I said, ‘Well, I guess I have to say yes now,’ ” David recalls.
David took Alm’s suggestion a step further by chronicling his own microbiome, collecting his feces every day in “plastic hats that look like something the Flying Nun would wear.” He washed his mouth with a chemical solution and spit into a tube to harvest mouth bacteria, popping all the samples into his refrigerator or freezer until he could get them to the lab. He customized an iPhone diary app so he and Alm, who joined the study, could track 349 different health and lifestyle measures, which included the timing and consistency of bowel movements, sleep quality and duration, blood pressure, weight, vitamin use and mood. They noted, in detail, the foods they ate, symptoms of any illnesses and medications used to treat those illnesses. By the end of the year, David had “10,000 measurements of how two people lived their lives.”
David, now 33 and at Duke University, regularly opens himself to new scientific challenges, though they aren’t always quite so personal. Before finishing his degree at MIT, he had already initiated one new field of research and delved into several others outside his expertise.

Awards committees and granting organizations have taken note. David has won the Beckman Young Investigator award and the Searle Scholars award, which support cutting-edge work by young scientists. Fresh out of graduate school, he became a junior fellow at Harvard, where he led his own research.

“He has an ability to see what the problem is and just get it done in the most straightforward way possible,” Alm says.
David spent most of his graduate student years in Alm’s lab writing and running computer code that calculated the ancient birth dates of genes, reproducing the most likely evolutionary histories of gene families and predicting capabilities of ancient microbes. Alone that would have been a nice contribution; many researchers thought untangling those relationships would be too computationally complex, Alm says.

But to get the full picture, David had to expand into other fields, working with geologists and geochemists to determine whether his predictions made sense in light of Earth’s geologic history. In a study that birthed a new field by marrying geochemistry and genetics, he and colleagues discovered that genes encoding oxygen-producing proteins appeared hundreds of thousands of years before oxygen began accumulating in early Earth’s atmosphere (SN Online: 12/21/10). For a study published in Science in 2008, he also delved into ecology, investigating how ocean microbes evolve into separate species without the physical boundaries that would keep them from mixing.

Population flux
The personal microbiome challenge was an unprecedented look at how friendly bacteria change over time and with lifestyle and dietary choices. Long known to play an important role in digestion, the gut microbiome has recently been implicated in health conditions including heart disease, obesity and asthma, and may even influence behavior (SN: 4/2/16, p. 23). Many people have suggested that humans and their microbes are so interdependent, they should be considered composite organisms (SN: 1/11/14, p. 14).

David, Alm and colleagues presented the results of their study in 2014 in Genome Biology. They found that the gut microbiome remains stable for months, but some events, such as travel, illness or changing the fiber content of the diet, can rapidly change the mix of gut microbes. Only a handful of studies have ever been done on this fine of a timescale, Alm says.

A project that would have made others hold their noses “might have been the most enjoyable thing I’ve done in science,” David says. The microbiome analysis relied on computer tools similar to ones he had used as an undergraduate researcher at Columbia University, making it intellectually satisfying.

But the real appeal was how others responded to the work. “People were immediately captivated by the work, and would start to tell me about their own gastrointestinal histories, odd things they had eaten and how that affected the bacteria in their gut,” David says. People sometimes asked his advice on what to eat to keep their gut microbiomes healthy, a question for which he didn’t have a clear answer. “There’s an irony to this,” he says. His voice drops to a whisper as he confesses: “I love junk food…. I shouldn’t be a poster child.”

Hooked on the microbiome, David began studying other people’s bacteria with the help of Peter Turnbaugh, a microbiologist then at Harvard and now at the University of California, San Francisco. By intentionally manipulating people’s diets, the researchers found that it takes only a day for a major dietary change, such as a meat-eater going vegetarian, to shift the composition of gut bacteria. The results, which surprised researchers who had thought such shifts would be more gradual, were reported in Nature in 2013 (SN Online: 12/11/13).

When he arrived at Duke in 2013 to start his own lab, David had a strong track record of developing computational tools to analyze complex datasets, says John Rawls, a microbiome researcher at Duke. But what makes David special isn’t just that he’s a good computer coder. “What sets him apart is his ability to incorporate technology and concepts from engineering into his work,” Rawls says.

Most labs that study the microbiome start with animal studies. But David began with a machine — an artificial gut for growing and manipulating intestinal microbes donated by human volunteers. The contraption consists of multiple growth chambers bristling with plastic tubes. Inside, what David has called “the world’s nastiest slurry” (a fecal sample from a donor) ferments in conditions similar to those in the intestines. One tube feeds into what looks like a dome hair dryer from a beauty salon. That’s a concession to neighboring researchers who complained about the pungent smell.

When graduate student Rachael Bloom joined the lab, David persuaded her to try a completely different way of growing bacteria from feces, designing chips with channels that separate out bacteria into microscopic drops of liquid. In just a few minutes, Bloom can create what are essentially thousands of tiny petri dishes, each with a single bacterium. Neither student nor mentor had any experience with the “microfluidics” technique, but David encouraged Bloom to try, and even be open to failure. “In retrospect, that could be really dangerous,” says Bloom, “but I have learned so much.”

David’s aptitude for engineering shows up at home, too. To keep his two preschool children from getting up too early, David rigged LED lights on a timer. The kids have to wait for the lights to go off before getting out of bed. His wife, a psychiatrist, reinforces the good behavior with a treat.

David says he “tends to be an optimist,” and just assumes his team will find a way over or around any hurdle. “He’s very adventurous. He’s very creative,” says Turnbaugh. “He’s one of the great people in microbiome research who is thinking outside the box and not just following a template.”

David has a simple explanation for why he continues to say yes to projects outside his comfort zone: “I’m easily fascinated.”

A half-century after scientists first introduced a vaccine to combat measles, the disease has been eliminated from a swath of the globe stretching from Canada to Chile — and all the countries in between.

The region is the first in the world to have eliminated the viral disease, the Pan American Health Organization and World Health Organization announced September 27. That’s different from eradication, which means an infectious disease has been scrubbed out permanently, worldwide. So far, only smallpox has been eradicated.

Though measles outbreaks still crop up occasionally in the Americas (this year 54 people have contracted the disease in the United States), they stem from travelers bringing the virus in from other parts of the world. A home-grown outbreak in the Americas hasn’t occurred since a 2002 outbreak in Venezuela.

Because measles still circulates widely elsewhere, vaccination remains crucial, PAHO Director Carissa Etienne noted in a press statement. “Our work on this front is not yet done,” she said. “We cannot become complacent with this achievement but must rather protect it carefully.”

Screens are everywhere. They adorn walls, perch on the backs of car seats and warm our hands. No one knows yet whether all of these screens, and their alluring displays and connections to the world, have any long-term effects on us. There is one group of people, though, for whom these ever-present screens may be particularly worrisome — kids.

Earlier recommendations on children’s screen time from the American Academy of Pediatrics were cut and dry. For kids under 2, screens were best avoided. Older kids got no more than two hours a day.

On October 21, scientists announced more nuanced guidelines in an attempt to guide parents on how screens of all sorts — TVs, tablets, phones and electronic readers — ought to fit into children’s lives. By moving away from the finger-wagging and diving deep into the shades of gray, the recommendations put more onus onto parents to decide what’s best for their families. These new suggestions are “a vast improvement over what we — pediatricians — have done in the past,” says pediatrician Michael Rich of Harvard Medical School.

For young children, the new guidelines offer concrete time limits. For children 5 and older, the recommendations are essentially aimed at having parents understand the value of media, how that changes with age, and perhaps most importantly, the importance of media-free time.

“We want them to focus on getting enough sleep, play, family routines, conversation, social time and exercise,” says pediatrician Jenny Radesky of the University of Michigan in Ann Arbor, who coauthored one of the new policy statements. “And we recommend [parents] try to do this by creating unplugged times of day and zones of the home, prioritizing family time and play, and having rules like device curfews.”

As a way to move closer to those media-free zones, researchers offer some recommendations for young children based on the latest scientific literature:

Avoid digital media use for children younger than 18 months to 24 months old (with the exception of video chatting).
If you want to introduce media to 18- to 24-month-olds, look for high-quality programs and watch the programs together.
For kids 2 to 5 years old, limit screen use to an hour a day of high-quality programming, and watch the programs together so you can help them understand what they see and relate it to the world.
Keep bedtimes, meals and play time media-free. That means parents, too, who have been known to become engrossed in their own screens and ignore their company.
Screens should be off an hour before bed, and they shouldn’t be in bedrooms.
Other recommendations include keeping a close eye on kids’ media content, turning off TVs or other screens when you’re not using them and avoiding screens as a way to regularly calm your child.

For children 5 and up, the guidelines no longer have a strict time limit. Instead, it puts the onus on parents to figure out their family’s plan. Losing the previous policy’s time limit may be a mistake, says pediatrician Victor Strasburger of the University of New Mexico School of Medicine, who helped write those earlier recommendations. “I was sorry they took out the two-hour recommendation. … I think the academy got a little gun-shy,” he says, afraid of offending parents whose children get way more than two hours of media a day.

The lack of clear limits for older children might be frustrating for parents who want simple rules. Rich sees these frustrations up close as the “Mediatrician,” an advice columnist who answers parents’ questions about digital health. “By being so respectful, [the new policy] runs the risk of not sending its message,” Rich says. But that flexibility may be helpful, because no two families are alike. “The best judge of this is ultimately the parent,” he says.

The question of how to fit media into children’s lives is really difficult. “We are dealing with two moving targets,” Rich says: the developing child and the developing media landscape. That means that simple answers don’t exist. And after all, parenting is more of an art than a science.

Scientists are still struggling with the distinctions between the different types of media — whether a TV show has different effects than an interactive app, for instance. But so far, there’s no evidence that kids under 2 can learn from apps, despite any “educational” marketing, Radesky says.

The guidelines address both media quality and quantity. High-quality programs “engage little minds on their learning edge, don’t use too many bells and whistles or fast editing to try to keep viewers’ attention, and craft their content for a dual audience,” Radesky says. These types of shows can be good sources of knowledge for preschoolers and their parents. Quantity matters too, especially as media becomes overused. Radesky has had parents tell her about putting their 2-year-old with a language delay in front of educational TV shows for five to six hours a day. “We really want to discourage parents from doing that,” she says.

For some families, the guidelines may be too lenient. For others, they may be too restrictive. And others may be overwhelmed at the prospect of investing the time and energy to really watch their children’s media use. But the principles behind these guidelines are solid. It’s definitely true that in addition to entertainment, media can offer rich learning experiences that would be otherwise unattainable. Even so, kids need to sleep, play, talk and explore their wondrous world — in real life.

Leprosy has been hiding out in red squirrels in Great Britain and Ireland, though the painful and disfiguring disease has rarely been transmitted between humans there since the Middle Ages.

The endangered bushy-tailed rodents (Sciurus vulgaris) have tested positive for leprosy-causing bacteria in several locations around the British Isles, researchers report November 11 in Science.

“It goes to show that once a disease has become extinct in humans, it could still exist in the environment if there was a suitable reservoir,” says study coauthor Stewart Cole, director of the Global Health Institute at the Swiss Federal Institute of Technology in Lausanne. In this case, squirrels seem to be ideal incubators for leprosy bacteria.
Until recently, leprosy, clinically known as Hansen’s disease, was thought to be transmitted only between humans. But in 2011, a team of scientists that included Cole found the disease in nine-banded armadillos in the southern United States (SN: 5/21/11, p. 9).

“One of the things we’ve never really understood about leprosy is how it can persist in populations at such low prevalence for such long periods of time,” says Richard Truman, a microbiologist at the National Hansen’s Disease Program in Baton Rouge, La., who wasn’t part of the study. The discovery that leprosy bacteria linger in various animal populations might help explain the disease’s sticking power in humans.

The relatively high prevalence of leprosy bacteria found in British red squirrel populations is also surprising, Truman says. Cole and his collaborators analyzed 110 red squirrel carcasses from Scotland, Ireland and two islands off the coast of England. All 13 of the visibly sick squirrels and 21 out of 97 seemingly healthy squirrels tested positive for the bacteria. Sick squirrels had skin lesions, patchy fur and nerve problems, similar to the symptoms seen in humans. The team found leprosy bacterium species Mycobacterium lepromatosis in squirrels from Scotland, Ireland, and the Isle of Wight, and Mycobacterium leprae in squirrels from remote Brownsea Island.

The strain found in the Brownsea Island squirrels is similar to the strain that made the rounds in medieval England, Cole says. That suggests the bacteria could have circulated in red squirrels for hundreds of years without changing very much (SN: 7/13/13, p. 18).

Today, more than 200,000 people are newly diagnosed with leprosy each year, mostly in Africa and Southeast Asia. But antibiotics, where available, easily clear up the infection. And up to 95 percent of people have some natural immunity to the disease, Truman says, so it’s not nearly as contagious as previously believed. So the odds of catching leprosy from a squirrel, an armadillo or another human are extremely slim. But since squirrels can carry other diseases too — such as rabies — it still might be best to observe the furry woodland creatures from a safe distance.

One of biology’s biggest achievements of 2016 was intentionally as small as possible: building a bacterium with only 473 genes. That pint-size genetic blueprint, the smallest for any known free-living cell, is a milestone in a decades-long effort to create an organism containing just the bare essentials necessary to exist and reproduce. Such “minimal genome” cells might eventually serve as templates for lab-made organisms that pump out medicines, make innovative chemicals for industry and agriculture, or churn out other molecules not yet imagined. The project also identified genes crucial for the microbe’s survival yet largely unfamiliar to science, highlighting major gaps in researchers’ grasp of life’s playbook.

The newly engineered bacterium was praised as a technical triumph. In 2010, researchers at the J. Craig Venter Institute in La Jolla, Calif., had stitched together a copy of the entire genome of the bacterium Mycoplasma mycoides and popped it into the cell of another bacterium whose genome had been removed. But that “synthetic cell,” dubbed JCVI-syn1.0, contained a full copy of an existing genome. With more than 1 million chemical building blocks of DNA, including 901 genes, it was far from minimal.
The latest version, JCVI-syn3.0, reported in March in Science (SN: 4/16/16, p. 6), has roughly half that much DNA. It’s also the first cell built using human design principles: One segment of the genome has genes for various processes, such as DNA repair, grouped together rather than scattered willy-nilly. Abandoning the untidiness of evolution for a logic-driven blueprint enables a “plug and play” approach, says Daniel Gibson, a member of the JCVI team. To tinker with a metabolic process such as glycolysis, for example, “Rather than changing one gene, then another, then another, you could pop out a whole module and then pop in a new one.”

Making such fundamental changes to the genome while still getting a functioning cell is noteworthy, says genome scientist George Church of Harvard University. “They could have found that, no matter what they did putting it together, it broke,” Church says.

The potential of synthetic cells is enormous, says Claudia Vickers, a biotechnologist at the Australian Institute for Bioengineering and Nanotechnology in Brisbane. Scientists have succeeded in engineering existing organisms such as yeast to help make, for example, malaria drugs. Now little cellular factories designed to be highly efficient and tailored to specific tasks are within sight, Vickers says.
The techniques used to build JCVI-syn3.0, especially when considered alongside other engineering tools such as the recently developed CRISPR/Cas9 system (SN: 9/3/16, p. 22), are a meaningful step toward the once-distant goal of self-replicating minimachines. “It’s important for the future it allows us to imagine,” Vickers says.

Since announcing JCVI-syn3.0, the team has used the same engineering techniques to turn the fast-growing bacterium Vibrio natriegens into a laboratory workhorse. The engineered Vibrio — dubbed Vmax — cuts the time it takes to do particular lab experiments in half compared with the original, Gibson says.

The minimal genome effort also aims at a larger philosophical question: What is life? In a lecture in 1984, origin-of-life expert Harold Morowitz discussed how studying the small and simple Mycoplasma genome might invigorate basic biology in much the way that studying the hydrogen atom sharpened questions for physics and chemistry. (Morowitz died in March, two days before the JCVI-syn3.0 work was published online.)

Many scientists, for example, were stunned to learn that JCVI-syn3.0 had 65 genes with no known function that were nevertheless required for survival. “This is one of our best studied organisms, and we haven’t the foggiest idea what those genes are doing,” says evolutionary genomics expert Laurence Hurst of the University of Bath in England. “It’s a brilliant result.”

Ecologists still don’t believe in fairies. But it may take magic to resolve a long-running debate over what causes the oddly regular spots of bare soil called fairy circles. A new approach now suggests combining the two main hypotheses.

Fairy circles, each among about six close neighbors, sprinkle arid grasslands in southern Africa and Australia “like a polka dot dress,” says ecologist Corina Tarnita of Princeton University. Two persistent ideas fuel debate over what’s making the arrays: stalemate warfare between underground termite colonies (SN Online: 3/28/13) or bigger plants monopolizing water (SN: 4/16/16, p. 8). “What if the reason that this debate is so long-lasting and it’s so hard to dismiss the other hypothesis is that both are right to a certain extent?” Tarnita asks.
Termites, by themselves, can in theory cause the mysterious arrangements, Tarnita, Princeton ecologist Robert Pringle and colleagues conclude from a new mathematical model they developed. They then linked their insect model with one showing plant competition causing fairy circles. The combined approach unexpectedly predicted a previously undescribed regular “clumping” pattern among the plants between fairy circles, the team reports January 18 in Nature.

In aerial pictures of fairy circles, the plants look like an even sea of vegetation between bare spots. To see if the plant patterns were real, the researchers visited the Namib Desert in southern Africa. Local park personnel “were constantly confused,” Tarnita says, because visitors usually study the bare patches. The vegetation clumped as predicted, in roughly hexagonal arrays as the circles themselves do. That confirmation suggests the combined model was working, the researchers say.

Hexagonal arrangements show up repeatedly in nature as creatures crowd together — for instance, as bees arrange cells in honeycombs, Pringle says. In southern Africa, termite colonies might create circular bare spots when insect nibbling prevents plant growth above the nest. Colonies too evenly matched to destroy each other persist as neighboring disks of barren soil, eventually packing into roughly hexagonal arrays.
But plants by themselves can make similar bare spots in harsh conditions, Tarnita explains. When a pioneer plant springs from dry, hot ground, for instance, opportunists follow, taking advantage of such benefits as the scrap of shade a pioneer casts. As these secondary plants grow bigger and suck up more of the limited water, they can create dead zones where nothing sprouts. Over time, these zones form hexagonal patterns, too.
Termites plus plants are probably producing the effect in the Namib Desert, Tarnita says. But the results might not apply to other fairy circle hot spots, such as Australia, she cautions. The main message of the new paper is that “different processes can lead to the exact same pattern,” she says.

Two proponents of the long-standing theories aren’t convinced the termite and plant models should be combined. Termite advocate Norbert Jürgens of the University of Hamburg welcomes the part of the new model that social insects alone “clearly” can cause fairy circles. But he’s not sure the plant clumping between circles indicates anything important. “Yes, of course there are always small-scale patterns among neighboring plants that are caused by feedback mechanisms,” he says. “However, these do not cause fairy circles.”

Nor does the new paper convert an ecologist advocating plant competition as the driver of fairy circle formation. Just showing that termites by themselves could create arrays with six neighbors isn’t enough, says Stephan Getzin of the Helmholtz Centre for Environmental Research GmbH-UFZ in Leipzig, Germany. “The degree of ordering or regularity that is shown by their insect model is not as strong as the ordering of [real-world] fairy circles,” he objects.

What’s needed now to resolve the debate isn’t necessarily fairy dust. Tarnita says she’s hoping for outdoor experiments.

Salmonella bacteria don’t want your body to starve on their account. The microbes’ motives, though, are (probably) purely poop-related.

The body sometimes sacrifices appetite to fight off infection: Less energy for the host also means less energy for the pathogen. Understanding how bacteria cope with this tactic can inform treatments.

When it reaches the gut, Salmonella enterica bacteria can trigger this type of anorexic response in their host, making it a good model for how microbes deal with less food. Researchers at the Salk Institute in California investigated salmonella fallout in mice. In lab tests, they found that the bacteria aren’t as virulent when a mouse isn’t eating, and they use the vagus nerve, a superhighway connecting gut to brain, to encourage eating. The bacteria make a protein called SIrP that appears to block signals that dampen appetite.

Keeping a host well fed plays out in the pathogen’s favor, the researchers write January 26 in Cell. That food has to go somewhere, and excreted waste gives salmonella place to live and an opportunity to spread.

Sleep is at the top of the list of conversation starters among parents with young children. With our recent cross-country move west, my family added a twist on sleep deprivation: jet-lagged children. To get some clarity on this new horror, I called developmental social scientist A.J. Schwichtenberg of Purdue University in West Lafayette, Ind.

Two main processes control sleep, Schwichtenberg explained. The first is the constant buildup of sleepiness, a pressure to sleep called homeostatic drive. Like adults, children reach a certain point and need to crash. “The longer they’re awake, the more likely it is they’ll want to go to sleep,” Schwichtenberg says. But unlike adults, children reach their limits sooner. That’s why most kids need to nap.

In the background of this sleepiness buildup is a roughly 24-hour daily rhythm. Called a circadian cycle, this rhythm is regulated by cues such as light, activity and even meals. When sleepiness coincides with a dark room, the result is usually blissful rest.

In the days after our recent move to the West Coast, however, this beautiful alignment went awry. Although the room was dark and quiet at 4 a.m., the two youngest people in our family were most definitely not sleepy.

After a few minutes of listening to my daughters whisper-shout about the funny hotel alarm clock, it finally sunk in: These kids were wide awake and ready to go. After all, their body clocks were still on the East Coast, where it was a reasonable 7 a.m. So like any conscientious parent, I threw an iPhone at them with unlimited Peppa Pig. That bought us a half hour. After that, my husband and I chugged hotel coffee and accepted our zombie fate.

In retrospect, Peppa might not have been the best choice. Schwichtenberg recommends keeping those obscenely early mornings dark and quiet. “You don’t want the world to be a superexciting place,” she says. Expose your child to the local time zone cues as much as possible. That means darkness when it’s time to sleep, lots of sunlight when it’s time to be awake, and meals at the right times.

The strongest of these reset cues is light, says Lisa Medalie, a behavioral sleep medicine specialist at University of Chicago Medicine. Sunlight in the morning tells the brain to be awake at the new time, she says. And at the end of the day, blue light, the kind emitted by electronic screens, should be avoided. Blue light dampens levels of the sleep-inducing hormone melatonin. To avoid this, screens ought to be turned off one hour before bedtime, she says.
Your newborn might escape jet lag entirely. Babies aren’t born with a solid circadian rhythm. Scientists think it takes about three months for babies to learn, with the help of lights and sounds, when to sleep and when to be awake (a skill my 2-year-old still struggles with). That means that if you are bravely traveling with a brand-spanking-new baby, jet lag might not be a big concern. “They sleep so much anyway, Schwichtenberg says. “There’s not a distinction between day and night.”

For quick trips of three days or less with older babies and kids, it might be best to just keep the whole crew on the same schedule as back home. In that time frame, it’s going to be difficult to shift cycles back and forth. The rule of thumb is that a person shifts about an hour per day.

If you’re going to be gone for longer than three days, you may want to begin shifting your child’s clock before you leave. An hour in either direction is a good place to start, Schwichtenberg says. We could have prepared our girls by having them stay up later than usual before our westward journey. And for the travel day itself, Schwichtenberg recommends traveling during the day. “Work your flight to arrive in the afternoon or evening,” so that your child will be tired on arrival, around the time for bed.

If you’ve traveled east and find yourself with a wired kid at 10 p.m., you might be tempted to turn to a drowse-inducing antihistamine such as Benadryl. But for some people, antihistamines can cause the opposite — disastrous — side effect of hyperactivity. Other drugs such as melatonin can be hard to dose correctly for young infants, Schwichtenberg says.

When trying to get older children to sleep, try to keep some semblance of normalcy. If you do a bedtime routine at home, use the same one while traveling. The biological plausibility of warm milk as a sleep aid isn’t settled, but it’s worth a shot. (Never underestimate the power of placebo.) Whatever you do, don’t despair. Your child will eventually adjust to her new time zone and you’ll get a full night’s sleep, at least until the next tooth erupts.