Around 558 million years ago, a strange … something dies on the floor of an ancient ocean. Its body, if you could call it that, is a two-inch-long oval with symmetric ribs running from its midline to its fringes. It is quickly buried in sediment, and gradually turns into a fossil.

While it sits in place, petrifying, waiting, the world around it changes. The Earth’s landmasses merge into a single supercontinent before going their separate ways. In the ocean, animal life explodes; for the first time, the world is home to eyes, shells, and mouths. Living things invade the land, coating it first in thin films of moss and lichens, and then covering it in huge forests. Insects rise, into existence, and then into the skies. A dinosaur empire rises and falls. Mammals finally take over, and one of them—a human by the name of Ilya Bobrovskiy—finally unearths the fossilized ribbed oval from its resting place.

The change can be baffling to many parents: Their young girls are masters of the universe, full of gutsy fire. But as puberty sets in, their confidence nosedives, and those same daughters can transform into unrecognizably timid, cautious, risk-averse versions of their former selves.

Over the course of writing our latest book, we spoke with hundreds of tween and teen girls, who detailed a striking number of things they don’t feel confident about: “making new friends,” “the way I dress,” “speaking in a group.” In our research, we worked with Ypulse, a polling firm that focuses on tweens and teens, to survey more than 1,300 girls between the ages of 8 and 18 and their parents. (The sample was broadly representative of the country’s teen population in terms of race and geographic distribution.) The data is more dramatic than we’d imagined: The girls surveyed were asked to rate their confidence on a scale of 0 to 10, and between the ages of 8 and 14, the average of girls’ responses fell from approximately 8.5 to 6—a drop-off of 30 percent.

When Beth Moore arrived in Houston in the 1980s, she found few models for young women who wanted to teach scripture. Many conservative Christian denominations believed that women should not hold authority over men, whether in church or at home; many denominations still believe this. In some congregations, women could not speak from the lectern on a Sunday or even read the Bible in front of men. But Moore was resolute: God, she felt, had called her to serve. So she went where many women in Texas were going in the ’80s: aerobics class. Moore kicked her way into ministry, choreographing routines to contemporary Christian music for the women of Houston’s First Baptist Church.

At the time, most Texas seminaries weren’t offering the kind of instruction she sought, so Moore found a private tutor. Slowly, she started getting invitations to speak at women’s luncheons and study groups, in exchange for a plate of food or a potted plant. In tiny church social halls, she laid the cornerstone of an evangelical empire.

Earlier this week, Tucker Carlson did the thing Tucker Carlson is consummately good at doing: He got angry on national television. The Fox News host’s performance, this time around, concerned the allegations of sexual assault Christine Blasey Ford has made against the Supreme Court nominee Brett Kavanaugh; Carlson, echoing an idea that has become a common one in the heated national debate that has resulted from the claims, was working to cast doubt on Ford’s overall credibility by casting doubt on a specific element of her story: the timing by which she finally made her private memories public. “It’s pretty straightforward,” Carlson said, flush with indignation. “If you believe a crime has been committed against you, you report it … It’s your obligation as a citizen.”

In certain parts of the United States, it’s getting more and more likely that rather than a game of dodgeball in gym class or a round of Heads-up, Seven-up as a break between lessons, students will instead find themselves doing downward-facing dog. The internet is saturated with yoga-based lesson plans, teacher-training courses, and “mindful” music playlists designed for schools, while programs for certified yoga instructors who want to bring their practice onto campus have also gained popularity.

While up-to-date data on the prevalence of school-based yoga is hard to come by, a 2015 survey led by the New York University psychologist Bethany Butzer identified three dozen programs in the United States that reach 940 schools and more than 5,400 instructors. School-based yoga programs, Butzer and her co-authors concluded, are “acceptable and feasible to implement.” The researchers also predicted that such programs would grow in popularity.

“New U.S.-China Tariffs Raise Fears of an Economic Cold War,” proclaimed a Washington Post headline. The New York Times alleged that the United States and China were already “on the cusp” of such a “new Cold War.” Driving this hysteria was the Trump administration’s Monday announcement unveiling tariffs on an additional $200 billion of Chinese imports, followed nearly immediately by a Chinese promise to retaliate. This back-and-forth has been ongoing since January, and a resolution does not seem anywhere close, if one’s even possible.

As the U.S.-China competition expands across multiple domains, there are even worries that trade tensions could, over the long term, make the prospect of a military confrontation between the two more likely. Which raises the urgent question: How does this end?

“Dear Caitlin,” an inscription in my 12th-grade yearbook begins. “I’m really very sorry that our friendship plummeted straight downhill after the first few months of school. Really, the blame rests totally on my shoulders. To tell you the truth, I’ve wanted to say this all year. I know you’ll succeed because you’re very smart and I regard you with the utmost respect … Take care—love always.”

He was headed to a prestigious college. I was headed to a small, obscure liberal-arts college, which was a tremendous achievement, not just because I was a terrible student, but also because I had nearly killed myself as a response to what he apologized for in my yearbook. He had tried to rape me during a date that I was very excited to have been asked on, and his attempt was so serious—and he was so powerful—that for a few minutes, I was truly fighting him off.

When Gül Dölen first gave ecstasy to octopuses, she didn’t know what to expect.

Dölen is a neuroscientist at the Johns Hopkins School of Medicine who studies how the cells and chemicals in animal brains influence animals’ social lives. Ecstasy, also known as MDMA, interests her because it’s known to make people feel more sociable, more interested in others, and less defensive. The same effects also occur in rats and mice—the animals that Dölen usually studies.

But octopuses are very different creatures. They’re clearly intelligent and their behavior is undoubtedly sophisticated, but their brains have a completely different architecture than those of mammals—for one thing, they’re shaped like donuts. “It’s organized much more like a snail’s brain than ours,” Dölen says. With such a dissimilar anatomy, she wondered whether these animals would respond to drugs in unpredictable ways. And to find out, she needed a way of assessing how sociable an octopus is.

This summer, the decree went out: We are living in a new geological chapter in the planet’s 4.5-billion-year history.

For a certain corner of the world, this was big news. You have probably heard of the Jurassic period (when dinosaurs ruled the Earth) or the Cambrian explosion (when complex animal life arose). Now we had a new name for our own neighborhood in time: We modern humans—you, me, and Jesus of Nazareth—were all born in the Meghalayan age. According to the global governing body of geologists, this new era began 4,200 years ago, when a global mega-drought sent ancient societies around the world into starvation and collapse.

How interesting!, you may think. I love science! And perhaps in an earlier era, that’s all you would have had to think. The dawn of the Meghalayan would have earned some wide-eyed headlines, made life slightly easier for a few researchers, and promptly been relegated to a second-round Jeopardy! question.

The world does not revolve around you, teens are often told. Indeed it doesn’t, as they are reminded every school-day morning when disabling their alarms. The average start time for public high schools, 7:59, requires teens to get up earlier than is ideal for their biological clocks, meaning many teens disrupt their natural sleep patterns every school day.

The world, apparently, does not revolve around parents either. Their lives also tend to be mismatched with school-day schedules, which usually end a good two hours before the typical American workday does. As Kara Voght recently wrote in The Atlantic, that leaves a daily gap of unsupervised time for many children, forcing their parents to find affordable care for their kid or to adjust their own working schedule.