Treatments for pain and other common health problems often fall short, leading to untold misery and frustration. So it’s not hard to understand the lure of a treatment that promises to be benign, natural and good for just about everything that ails you. Enter cannabidiol, or CBD.
So far, the U.S. Food and Drug Administration has approved only one drug containing the chemical: a treatment for rare and severe forms of epilepsy. But that hasn’t stopped people from trying CBD to relieve arthritis, morning sickness, pain, depression, anxiety, addiction, inflammation and acne. And it hasn’t kept companies from marketing the heck out of CBD-infused anything. It’s the sort of situation that gets us wondering: What’s the science here? The science is skimpy at best, neuroscience writer Laura Sanders reports in this issue. Clinical trials, some of which included children, were conducted to determine safety and efficacy before the FDA approved the first CBD-based epilepsy drug in 2018. But much less research has been done on CBD with regard to other ailments.
Adding to the intrigue, CBD can be extracted from marijuana, though CBD lacks the capacity to induce a buzzy high like its sister molecule THC. So government restrictions have been tight, and scientists have had a hard time getting access to CBD for studies. That makes it less likely that we’ll get clear answers anytime soon on whether CBD is indeed a panacea, or just another triumph of hype.
The surplus of unknowns hasn’t stopped companies from marketing hundreds of CBD products as treatments, attempting to avoid scrutiny by adding disclaimers that the products “are not intended to diagnose, treat or cure or prevent any disease.” But with such large gaps in the research, people trying these products in the hope of benefit become inadvertent guinea pigs.
The process of science may be frustratingly slow, but it can get the job done. In the last decade, clinical trials on vitamin D, for example, have found that despite much excitement surrounding the “sunshine vitamin,” there’s no definitive evidence of benefits in preventing heart disease or cancer. In our recent cover story “Vitamin D supplements aren’t living up to their hype,” contributing correspondent Laura Beil described the years of effort needed to develop that data (SN: 2/2/19, p. 16). As journalists, we see a big part of our mission as making sure that people have access to accurate, timely information about medical research, so people can make informed decisions for themselves and their families. That’s especially important when it involves products that people can self-prescribe. These two articles — by skilled journalists who put weeks of effort into reading studies, talking with researchers and investigating the business side — are great examples of how sophisticated and useful consumer science journalism can be. Most people look for health information online, but Googling a term like “CBD oil” serves up a muddle of marketing masquerading as impartial information.
CBD may end up being a worthwhile treatment for some problems beyond epilepsy; it’s too early to know. But while we wait for the evidence, it’s essential to know where the science stands right now.
THE WOODLANDS, Texas — Grains of dust from the edge of the solar system could be finding their way to Earth. And NASA may already have a handful of the debris, researchers report.
With an estimated 40,000 tons of space dust settling in Earth’s stratosphere every year, the U.S. space agency has been flying balloon and aircraft missions since the 1970s to collect samples. The particles, which can be just a few tens of micrometers wide, have long been thought to come mostly from comets and asteroids closer to the sun than Jupiter (SN Online: 3/19/19).
But it turns out that some of the particles may have come from the Kuiper Belt, a distant region of icy objects orbiting beyond Neptune, NASA planetary scientist Lindsay Keller said March 21 at the Lunar and Planetary Science Conference. Studying those particles could reveal what distant, mysterious objects in the Kuiper Belt are made of, and perhaps how they formed (SN Online: 3/18/19).
“We’re not going to get a mission out to a Kuiper Belt object to actually collect [dust] samples anytime soon,” Keller said. “But we have samples of these things in the stratospheric dust collections here at NASA.” One way to find a dust grain’s home is to probe the particle for microscopic tracks where heavy charged particles from solar flares punched through. The more tracks a grain has, the longer it has wandered in space — and the more likely it originated far from Earth, says Keller, who works at the Johnson Space Center in Houston.
But to determine precisely how long a dust grain has spent traveling space, Keller first needed to know how many tracks a grain typically picks up per year. Measuring that rate required a sample with a known age and known track density — criteria met only by moon rocks brought back on the Apollo missions. But the last track-rate estimate was done in 1975 and with less precise instruments than are available today. So Keller and planetary scientist George Flynn of SUNY Plattsburgh reexamined that same Apollo rock with a modern electron microscope. They found that the rate at which rocks pick up flare tracks was about 20 times lower than the previous study estimated.
That means it takes longer for dust flakes to pick up tracks than astronomers assumed. When Keller and Flynn counted the number of tracks in 14 atmospheric dust grains, the pair found that some of the particles must have spent millions of years out in space — far too long to have come just from between Mars and Jupiter.
Grains specifically from the Kuiper Belt would have wandered 10 million years to reach Earth’s stratosphere, the researchers calculated. That’s “pretty solid evidence that we’re collecting Kuiper Belt dust right here,” Keller says. Four of the particles contained minerals that had to have formed through interactions with liquid water. That’s surprising; the Kuiper Belt is thought to be too cold for water to be liquid.
“Many of these particles, if they in fact are from the Kuiper Belt, tell you that some of the minerals in Kuiper Belt objects formed in the presence of liquid water,” Keller says. The water probably came from collisions between Kuiper Belt objects that produced enough heat to melt ice, he says.
“I think it’s incredible if Lindsay Keller has shown that he has pieces of Kuiper Belt dust in his lab,” says planetary scientist Carey Lisse of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. But more work needs to be done to confirm that the dust really came from the Kuiper Belt, he says, and wasn’t just sitting on an asteroid for millions of years. “Lindsay needs to get a lot more samples,” Lisse says. “But I do think he’s on to something.”
Lisse works on NASA’s New Horizons mission, which found plenty of dust in the outer solar system and measured its abundance near Pluto when the spacecraft flew past the dwarf planet in 2015. Based on those results, he finds it unsurprising that some of that dust has made it to Earth. But it is “really cool,” he says. “We can actually try to figure out what the Kuiper Belt is made of.”
Editor’s note: This story was updated April 8, 2019, to correct that the newly calculated flare track rate was about 20 times lower than the rate calculated in 1975, not two orders of a magnitude lower.
A new member of the human genus has been found in a cave in the Philippines, researchers report.
Fossils with distinctive features indicate that the hominid species inhabited the island now known as Luzon at least 50,000 years ago, according to a study in the April 11 Nature. That species, which the scientists have dubbed Homo luzonensis, lived at the same time that controversial half-sized hominids named Homo floresiensis and nicknamed hobbits were roaming an Indonesian island to the south called Flores (SN: 7/9/16, p. 6). In shape and size, some of the fossils match those of corresponding bones from other Homo species. “But if you take the whole combination of features for H. luzonensis, no other Homo species is similar,” says study coauthor and paleoanthropologist Florent Détroit of the French National Museum of Natural History in Paris.
If the find holds up to further scientific scrutiny, it would add to recent fossil and DNA evidence indicating that several Homo lineages already occupied East Asia and Southeast Asian islands by the time Homo sapiens reached what’s now southern China between 80,000 and 120,000 years ago (SN: 11/14/15, p. 15). The result: an increasingly complicated picture of hominid evolution in Asia.
Excavations in 2007, 2011 and 2015 at Luzon’s Callao Cave yielded a dozen H. luzonensis fossils at first — seven isolated teeth (five from the same individual), two finger bones, two toe bones and an upper leg bone missing its ends, the scientists say. Analysis of the radioactive decay of uranium in one tooth suggested a minimum age of 50,000 years. Based on those fossils, a hominid foot bone found in 2007 in the same cave sediment was also identified as H. luzonensis. It dates to at least 67,000 years ago. had molars that were especially small, even smaller than those of hobbits, with some features similar to modern humans’ molars. The hominid also had relatively large premolars that, surprisingly, had two or three roots rather than one. Hominids dating to several hundred thousand years ago or more, such as Homo erectus , typically had premolars with multiple roots. H. luzonensis finger and toe bones are curved, suggesting a tree-climbing ability comparable to hominids from 2 million years ago or more. It’s unclear whether H. luzonensis was as small as hobbits, Détroit says. The best-preserved hobbit skeleton comes from a female who stood about a meter tall. Based on the length of the Callao Cave foot bone, Détroit’s team suspects that H. luzonensis was taller than that, although still smaller than most human adults today.
As with hobbits, H. luzonensis’ evolutionary origins are unknown. Scientists think that hobbits may have descended from seagoing H. erectus groups, and perhaps H. luzonensis did too, writes paleoanthropologist Matthew Tocheri of Lakehead University in Thunder Bay, Canada, in a commentary published with the new report. Evidence suggests that hominids reached Luzon by around 700,000 years ago (SN Online: 5/2/18). So H. erectus may have also crossed the sea from other Indonesian islands or mainland Asia to Luzon and then evolved into H. luzonensis with its smaller body and unusual skeletal traits, Détroit speculates, a process known as island dwarfing.
But some scientists not involved in the research say it’s too soon to declare the Luzon fossils a brand-new Homo species. Détroit’s group, so far, has been unable to extract ancient DNA from the fossils. So “all [evolutionary] possibilities must remain open,” says archaeologist Katerina Douka of the Max Planck Institute for the Science of Human History in Jena, Germany.
The mosaic of fossil features that the team interprets as distinctive, for instance, may have been a product of interbreeding between two or more earlier Homo species, creating hybrids, but not a new species.
Or perhaps a small population of, say, H. erectus that survived on an isolated island like Luzon for possibly hundreds of thousands of years simply acquired some skeletal features that its mainland peers lacked, rather than evolving into an entirely new species, says paleoanthropologist María Martinón-Torres.
Those questions make the new fossils “an exciting and puzzling discovery,” says Martinón-Torres, director of the National Research Centre on Human Evolution in Burgos, Spain.
If the unusual teeth and climbing-ready hand and foot bones found at Callao Cave occurred as a package among Luzon’s ancient Homo crowd, “then that combination is unique and unknown so far” among hominids, Martinón-Torres says. Only a more complete set of fossils, ideally complemented by ancient DNA, she adds, can illuminate whether such traits marked a new Homo member.
Ketamine banishes depression by slowly coaxing nerve cells to sprout new connections, a study of mice suggests. The finding, published in the April 12 Science, may help explain how the hallucinogenic anesthetic can ease some people’s severe depression.
The results are timely, coming on the heels of the U.S. Food and Drug Administration’s March 5 approval of a nasal spray containing a form of ketamine called esketamine for hard-to-treat depression (SN Online: 3/21/19). But lots of questions remain about the drug. “There is still a lot of mystery in terms of how ketamine works in the brain,” says neuroscientist Alex Kwan of Yale University. The new study adds strong evidence that newly created nerve cell connections are involved in ketamine’s antidepressant effects, he says.
While typical antidepressants can take weeks to begin working, ketamine can make people feel better in hours. Scientists led by neuroscientist Conor Liston suspected that ketamine might quickly be remodeling the brain by spurring new nerve cell connections called synapses. “As it turned out, that wasn’t true, not in the way we expected, anyway,” says Liston, of Cornell University.
Newly created synapses aren’t involved in ketamine’s immediate effects on behavior, the researchers found. But the nerve cell connections do appear to help sustain the drug’s antidepressant benefits over the longer term.
To approximate depression in people, researchers studied mice that had been stressed for weeks, either by being restrained daily in mesh tubes, or by receiving injections of the stress hormone corticosterone. These mice began showing signs of despair, such as losing their taste for sweet water and giving up a struggle when dangled by their tails. Three hours after a dose of ketamine, the mice’s behavior righted, as the researchers expected. But the team found no effects of the drug on nerve cells’ dendritic spines — tiny signal-receiving blebs that help make new neural connections. So the creation of new synapses couldn’t be responsible for ketamine’s immediate effects on behavior, “because the behavior came first,” Liston says.
When the researchers looked over a longer time span, though, they found that these new synapses were key. About 12 hours after ketamine treatment, new dendritic spines began to pop into existence on nerve cells in part of the mice’s prefrontal cortex, the brain area responsible for complex thinking. These dendritic spines seemed to be replacing those lost during the period of stress, often along the same stretch of neuron.
To test if these newly created spines were important for the mice’s improved behavior, the researchers destroyed the spines with a laser a day after the ketamine treatment. That effectively erased ketamine’s effects, and the mice again exhibited behavior resembling depression, including struggling less when held by their tails. (The mice kept their regained sugar preference.)
Research on humans has also suggested that depressed people have diminished synapses, says Ronald S. Duman, a neuroscientist at Yale University not involved in the study. The new work adds more support to those findings by showing that destroying new synapses can block ketamine’s behavioral effects. “That’s a huge contribution and advance,” Duman says.
The sun’s rhythm may have set the pace of each day, but when early humans needed a way to keep time beyond a single day and night, they looked to a second light in the sky. The moon was one of humankind’s first timepieces long before the first written language, before the earliest organized cities and well before structured religions. The moon’s face changes nightly and with the regularity of the seasons, making it a reliable marker of time.
“It’s an obvious timepiece,” Anthony Aveni says of the moon. Aveni is a professor emeritus of astronomy and anthropology at Colgate University in Hamilton, N.Y., and a founder of the field of archaeoastronomy. “There is good evidence that [lunar timekeeping] was around as early as 25,000, 30,000, 35,000 years before the present.”
When people began depicting what they saw in the natural world, two common motifs were animals and the night sky. One of the earliest known cave paintings, dated to at least 40,000 years ago in a cave on the island of Borneo, includes a wild bull with horns. European cave art dating to about 37,000 years ago depicts wild cattle too, as well as geometric shapes that some researchers interpret as star patterns and the moon.
For decades, prehistorians and other archaeologists believed that ancient humans were portraying what they saw in the natural world because of an innate creative streak. The modern idea that Paleolithic people were depicting nature for more than artistic reasons gained traction at the end of the 19th century and was further developed in the early 20th century by Abbé Henri Breuil, a French Catholic priest and archaeologist. He interpreted the stylistic bison and lions in the cave paintings and carvings of southern France as ritual art designed to bring luck to the hunt.
In the 1960s, a journalist–turned–amateur anthropologist proposed even more practical purposes for these drawings and other artifacts: They were created for telling time.
In the early days of the Apollo space missions, the journalist, Alexander Marshack, was writing a book about how the course of human history culminated in the moon shot. He delved into prehistory, trying to understand the earliest concepts of timekeeping and agriculture (SN: 4/14/79, p. 252).
“I had a profound sense of something missing,” Marshack wrote in his 1972 book, The Roots of Civilization. Formal science, including astronomy and math, apparently had begun “suddenly,” he noted. Same with writing, agriculture, art and the calendar. But surely these cognitive leaps took thousands of years of preparation, Marshack reasoned: “How many thousands was the question.”
To find out, he examined ancient bone carvings and wall art from locations including caves in Western Europe and fishing villages of equatorial Africa. He interpreted what was seen by some as simple dots and dashes or depictions of animals and people as sophisticated tools for keeping track of time — via the moon. Today, some experts support his thesis; others remain unconvinced. It’s easy enough to keep track of the seasons just by paying attention to the environment, of course. Throughout the world, animals like deer and cattle are pregnant through the winter’s dark privation; they give birth when the leaves appear on trees and when grasses grow tall.
Early humans of 30,000 years ago frequently connected the changes in these “phenophases,” the seasonal stages of flora and fauna, with the appearance of certain stars and the phases of the moon, says science historian and astronomer Michael Rappenglück of the Adult Education Center and Observatory in Gilching, Germany. He refers to early cave depictions as “paleo-almanacs” because they combined time-reckoning with information related to the cycles of life.
As Rappenglück puts it, simply noting the spinning of the seasons would not be enough to keep time. For one thing, flora and fauna change from place to place, and even 30,000 years ago, humans were traveling great distances in search of food. They needed something more constant to help them tell time.
“People carefully watched the course of the moon, noting its position over the natural horizon and the change of its phases,” Rappenglück wrote in the 2015 Handbook of Archaeoastronomy and Ethnoastronomy.
In the 1960s, Marshack, the first to argue that Paleolithic people were connecting the moon with time, sifted through dusty cabinets in French museums, retrieving bone and antler pieces that had been worked by humans. Others had interpreted the etchings on these objects as the by-product of point-sharpening, or maybe, as most before Breuil thought, abstract artworks made by idle hands.
But Marshack saw the earliest examples of sky almanacs. The etchings were numerical and notational, he argued. On a bone shard from a prehistoric settlement called Abri Blanchard in France, dating to 28,000 years ago, he found a pattern of pits, some with commalike curves and some round. He viewed it as a record of lunar cycles.
Deeply excited by the find, Marshack soon brought his conclusions to archaeologists and anthropologists throughout Europe and the United States. Some of these experts were impressed, according to accounts at the time.
Hunters who could figure out when the night would be illuminated by moonlight would have had an “adaptive advantage,” Aveni says. “That is so much what the cave paintings are about,” he says, referring to the tally marks near the animals on the walls of the Chauvet Cave in France and elsewhere.
Regarding Marshack’s speculations about the Blanchard bone shard, paleoanthropologist Ian Tattersall is still unsure. “We know Ice Age European art was highly symbolic, and there is no doubt that [ancient people] perceived symbols all around them in nature. And it is pretty certain that the moon played a huge role in their cosmology, and that they were fully aware of its cycle,” says Tattersall, curator emeritus of human origins at the American Museum of Natural History in New York City. “Beyond that, all bets are off.”
Thirteen notches In the decades after Marshack published his findings, historians and anthropologists began noticing similar lunar motifs throughout the archaeological record of this time period and afterward, Aveni notes. “There are more than one of these items that have markings on them that might relate to the moon,” he says.
The Venus of Laussel is one extraordinary example. It is a carving of a voluptuous woman, one hand resting on her abdomen, the other raised and holding a bison horn etched with 13 notches. Her face is turned toward the horn. The figure was carved between 22,000 and 27,000 years ago, in a rock-shelter in the Dordogne region of southwestern France. Some archaeologists now think the 13 notches represent the number of lunar cycles in a solar year — and, approximately, the average number of menstrual cycles. Though modern scientists have debunked any direct connection between the cycles of the moon and human fertility, ancient people would have recognized the parallel timing; the lunar cycle repeats every 29.5 days, roughly the same schedule as the average woman’s menstrual cycle. People of 30,000 years ago could have used the moon and stars to plan their pregnancies, Rappenglück speculates.
Cave paintings in the Dordogne region may be depictions of the lunar and menstrual cycles. Specifically, the Lascaux cave paintings, dating to 17,000 years ago, are best known for their curvy, sweeping depictions of horses and bulls. Beyond the cave entrance, past what is called the Hall of Bulls, is a dead-end passage called the Axial Gallery. Red aurochs, an extinct form of cattle, stand in a group. A huge black bull stands apart from them. Across the gallery, a pregnant horse gallops above a row of 26 black dots. The mare is running toward a massive stag, with front legs invisible behind 13 additional evenly spaced dots.
The animals may represent seasons, Rappenglück suggests. In Europe, bovines calve in the spring; horses both foal and mate in the late spring. The deer rut takes place in early autumn, and the wild goats known as ibex mate around the winter solstice.
To Rappenglück, the dots depict the 13 full moons of the lunar cycle. The 26 dots may roughly represent the days of a sidereal month, or the time it takes the moon to return to the same position in the sky relative to the stars. “The striking row of dots is a kind of a time-unit,” he wrote in 2004.
Critics have said Marshack’s work overinterprets many artifacts from Africa and Europe, some of which contain markings at the limit of naked-eye visibility (SN: 6/9/90, p. 357).
“By modern standards of evidence, he is playing with numerological coincidences,” art historian James Elkins wrote in 1996 in an article that is part critique and part celebration. Elkins noted that Marshack countered his doubters by throwing their uncertainty back at them, arguing that better explanations were lacking.
“Nights were real nights at that time, and Paleolithic people certainly had deep insights into what was going on in the sky,” says Harald Floss, an anthropologist at the University of Tübingen in Germany who studies the origin of art. “But I would not risk saying more.”
Look up at the moon and you’ll see roughly the same patterns of light and shadow that Plato saw about 2,500 years ago. But humankind’s understanding of Earth’s nearest neighbor has changed considerably since then, and so have the ways that scientists and others have visualized the moon.
To celebrate the 50th anniversary of the Apollo 11 moon landing, here are a collection of images that give a sense of how the moon has been depicted over time — from hand-drawn illustrations and maps, to early photographs, to highly detailed satellite images made possible by spacecraft such as NASA’s Lunar Reconnaissance Orbiter. The images, compiled with help from Marcy Bidney, curator of the American Geographical Society Library at the University of Wisconsin–Milwaukee, show how developments in technology such as the telescope and camera drove ever more detailed views of Earth’s closest celestial companion.
Atlas Coelestis, Johann Gabriel Doppelmayr, 1742 Ancient Greek philosophers like Plato thought the moon and other celestial bodies revolved around a fixed Earth. This 1742 diagram by German scientist Johann Gabriel Doppelmayr depicts that idea. The thinkers saw the moon as perfect and struggled to explain its dark marks. In 1935, one of the moon’s most conspicuous craters was named after Plato.
Astronomicum Caesareum, Michael Ostendorfer, 1540 This hand-colored woodcut by German painter Michael Ostendorfer appears in Astronomicum Caesareum, a vast collection of astronomical knowledge compiled by the German author Petrus Apianus and published in 1540. The image is an example of how astronomers in this early Renaissance period began to stylize the moon by giving it a face, Bidney says.
The book also contains more than 20 exquisitely detailed moving paper instruments, or volvelles, that helped predict lunar eclipses, calculate the position of the stars and more.
De Mundo, William Gilbert, ca. 1600 Created around 1600, this sketch is the oldest known lunar map, and was drawn using the naked eye. William Gilbert, physician to Queen Elizabeth I, imagined that the bright spots were seas and the dark spots land, and gave some features names, such as Regio Magna Orientalis, which translates as “Large Eastern Region” and roughly coincides with the vast lava plain known today as Mare Imbrium.
Sidereus Nuncius, Galileo, 1610 The telescope made it far easier to see the moon’s topography. By Galileo, these 1610 lunar maps are some of the first published to rely on telescope views. His work supported the Copernican idea that the moon, Earth and other planets revolved around the sun.
Although Galileo’s moon drawings were not the first to rely on telescope observations — English astronomer Thomas Harriot created the first sketch in 1609 — Galileo’s were the first published. These images appeared in his astronomical treatise Sidereus Nuncius.
Selenographia, Johannes Hevelius, 1647 In 1647, Polish astronomer Johannes Hevelius, published the first lunar atlas, Selenographia. The book contains more than 40 detailed drawings and engravings, including this one, that show the moon in all its phases. Hevelius also included a glossary of 275 named surface features.
To create his images, Hevelius, a wealthy brewer, constructed a rooftop observatory in Gdańsk and fitted it with a homemade telescope that magnified the moon 40 times. Hevelius is credited with founding the field of selenography, the study of the moon’s surface and physical features.
First known lunar photo, John William Draper, 1840 Photography opened a new way to capture the moon. Taken around 1840 by British-born chemist and physician John William Draper, this daguerreotype is the first known lunar photo. Spots are from mold and water damage.
“Moon over Hastings”, Henry Draper, 1863 Photos of the moon quickly improved. John William Draper’s son Henry, a physician like his father, also developed a passion for photographing the night sky. He shot this detailed image from his Hastings-on-Hudson observatory in New York in 1863, and went on to become a pioneer in astrophotography.
Lunar Reconnaissance Orbiter, NASA, 2018 This 2018 image, from NASA’s Lunar Reconnaissance Orbiter, shows the moon’s familiar face in incredible detail. Now we know its marks are evidence of a violent past and include mountain ranges, deep craters and giant basins filled with hardened lava.
Lunar farside, Chang’e-4, 2019 Countless images now exist of the moon’s illuminated face, but only relatively recently have astronomers managed to capture shots of the moon’s farside, using satellites. Then in February, China’s Chang’e-4 lander and rover became the first spacecraft to land there. This is the first image captured by the probe.
By mounting a water distillation system on the back of a solar cell, engineers have constructed a device that doubles as an energy generator and water purifier.
While the solar cell harvests sunlight for electricity, heat from the solar panel drives evaporation in the water distiller below. That vapor wafts through a porous polystyrene membrane that filters out salt and other contaminants, allowing clean water to condense on the other side. “It doesn’t affect the electricity production by the [solar cell]. And at the same time, it gives you bonus freshwater,” says study coauthor Peng Wang, an engineer at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia. Solar farms that install these two-for-one machines could help meet the increasing global demand for freshwater while cranking out electricity, researchers report online July 9 in Nature Communications.
Using this kind of technology to tackle two big challenges at once “is a great idea,” says Jun Zhou, a materials scientist at Huazhong University of Science and Technology in Wuhan, China, not involved in the work.
In lab experiments under a lamp whose illumination mimics the sun, a prototype device converted about 11 percent of incoming light into electricity. That’s comparable to commercial solar cells, which usually transform some 10 to 20 percent of the sunlight they soak up into usable energy (SN: 8/5/17, p. 22). The researchers tested how well their prototype purified water by feeding saltwater and dirty water laced with heavy metals into the distiller. Based on those experiments, a device about a meter across is estimated to pump out about 1.7 kilograms of clean water per hour.
“It’s really good engineering work,” says George Ni, an engineer who worked on water distillation while a graduate student at MIT, but was not involved in the new study. “The next step is, how are you going to deploy this?” Ni says. “Is it going to be on a roof? If so, how do you get a source of water to it? If it’s going to be [floating] in the ocean, how do you keep it steady” so that it isn’t toppled by waves? Such practical considerations would need to be hammered out for the device to enter real-world use.
Astronomy lovers are not the only ones excited about the 50th anniversary of the moon landing. Publishers are also taking note, serving up a pile of books to mark the occasion.
Are you looking for a general overview of the birth of the U.S. space program? Would you rather geek out on the technical details of the Apollo missions? How about flipping through a collection of photographs from the era? Science News staff took a look at the offerings and picked out a few favorites to help you decide. There’s something for everyone in the list below. For history aficionados James Donovan Little, Brown and Co., $30
This retelling of the space race begins with the launch of the Soviet Union’s Sputnik satellite in 1957 and culminates in the historic Apollo 11 mission 12 years later. The book offers insights into the personalities of the astronauts, engineers and others who made the U.S. space program a success. For detail-obsessed NASA fans Charles Fishman Simon & Schuster, $29.99
Getting to the moon demanded a million hours of work for each hour spent in space, this book argues. Accordingly, the story focuses on the engineers, coders, project managers and others who toiled to get the Apollo program off the ground. For anyone who ever dreamed of being an astronaut J.L. Pickering and John Bisney Univ. of Florida, $45
Packed with hundreds of photos, some published for the first time, this coffee-table book reads like a photo album of the Apollo 11 mission. The images focus on candid moments from astronaut training, as well as the excitement of liftoff, the historic landing and the return home of the three men.
For readers ready for a sober view of Apollo Roger D. Launius Smithsonian Books, $27.95
A space historian takes the Apollo program off its pedestal to examine it from multiple angles: as a cog in the Cold War political machine, an engineering endeavor riddled with as many failures as feats of glory and an iconic cultural moment. The book explores both positive and negative viewpoints on the U.S. moonshot project from scientists, politicians, the media and the public during the space race and beyond.
For fans of graphic novels Jonathan Fetter-Vorm Hill and Wang, $35
Colorful and detailed, the comic-style illustrations in this book of graphic nonfiction bring the moon landing to life. Much of the astronauts’ dialog is based on real recordings, making the book feel particularly authentic.
For self-improvement buffs Richard Wiseman TarcherPerigee, $26
A psychologist takes practical lessons from the Apollo era and suggests ways to apply them to everyday problems, from changing careers to raising a family.
For space enthusiasts David Baker Arcturus Publishing Limited, $19.99
A former NASA engineer uses photographs, illustrations, blueprints and other documents to guide readers through a concise history of the space race and the Apollo program, from the beginnings of rocket science to the successful return home of the Apollo 11 crew.
For history wonks with a soft spot for psychology Basil Hero Grand Central Publishing, $22
The Apollo astronauts rarely gave personal interviews. But now that they’re getting older, the astronauts are starting to get introspective. This book distills conversations with the 12 lunar voyagers still alive into general wisdom on conquering fear and appreciating life.
For photography lovers Deborah Ireland Ammonite Press, $14.95
This slim book offers an offbeat take on the mission to the moon, telling the story of the Apollo program through the development of the Hasselblad cameras that Neil Armstrong and Buzz Aldrin used to document their time on the lunar surface. Science News is a participant in the Amazon Services LLC Associates Program. Please see our FAQ for more details.
The possibility of life … on other planets has stimulated many people’s imaginations…. In the Feb. 9 Nature, James C. G. Walker of Yale University studies the possible parameters of such a search and comes to some pessimistic conclusions.
Update Walker estimated it could take 1,400 to 14 million years to contact E.T. with the available technology. That’s way longer than researchers have spent listening for alien radio signals and scouring the sky with telescopes and satellites (SN: 11/21/20, p. 18).
Despite the silence, scientists have sent their own messages into the void. In 1974, Earth sent a string of binary code from the Arecibo Observatory in Puerto Rico. Years later, arguably the most famous message — the Golden Record — made its way to space aboard NASA spacecraft (SN: 8/20/77, p. 124).
If aliens ever reach out, they may send quantum dispatches, scientists say (SN: 8/13/22, p. 5). Even so, the aliens are likely so far from Earth that their civilization will have collapsed by the time we get the message (SN: 4/14/18, p. 9).
“I remember carrying my little sister on my back because she’s too tired and walking through the huge sunflower fields … and me feeling so tired I didn’t think I could walk another step.”
“I remember being in a taxi with my mother, coming back to the man who had been violently abusive to all of us…. Her words to me were, ‘Just trust me, Trish. Just trust me.’ ” “I’m waiting at a train station … to meet my mother who I haven’t seen in many years…. Hours pass and eventually I try to call her … and she says to me, ‘I’m sorry, Trish. My neighbor was upset, and I needed to stay back with them.’ And her voice was slurring quite a lot, so I knew she had been drinking.”
Tran, who lives in Perth, Australia, is dispassionate as she describes a difficult childhood. Her account lacks what are generally considered classic signs of trauma: She makes no mention of flashbacks, appears to have a generally positive outlook and speaks with relative ease about distressing events. Yet she narrates her life growing up and living in the Australian Outback as a series of disconnected events; her life story lacks connective glue.
Two photos of Trish Tran. On the left is a black and white family photo with Tran as a small child sitting on her fathers lap while to their right her mother holds a baby and her three siblings stand. The photo on the right is Tran as an adult holding a microphone and smiling. That disjointed style is not how people, at least people in the West, tend to talk about themselves, says psychologist Christin Camia. Autobiographical accounts, like any good narrative, typically contain a curation of key past experiences, transitions linking those experiences and larger arcs about where life is headed. People use these stories to make sense of their lives, says Camia, of Zayed University’s Abu Dhabi campus in the United Arab Emirates.
But a growing body of evidence from fields as wide-ranging as psychology, neuroscience, linguistics, philosophy and literary studies suggests that, as with Tran, trauma can shatter the narrative coherence of one’s life. People lose the plot.
Life’s crises can trigger an existential crisis, Camia says. People think: “I don’t know who I am, and I don’t know where I go from here.” One therapy now in testing aims to re-tether traumatized individuals to their mental timelines, or their sense of themselves as connected across past, present and future. The therapy focuses on the future, which once rife with possibilities now appears as a void. It asks: What would it take for someone like Tran, or anyone traumatized by war, abuse, mass shootings, the ongoing pandemic and other calamities, to flip their life script, to say that they know who they are and where they go from here?
People maintain a sense of self across time In a nod to an established research approach, I have asked Tran to tell me her story in two parts. First, she should narrate seven snapshots of key moments in her life. Second, Tran, who is a lecturer on mental health recovery at Curtin University in Perth, should stitch those snapshots together to tell me how she became who she is today.
The first task comes easy. The second task eludes her. She switches to generalities. “I’ve always been a highly reflective person,” she says. “I’ve had to rely on my brains to keep myself and my family alive.”
I try to nudge her toward specifics, but her timeline disintegrates. She repeatedly attempted suicide. Her mother brought home many violent men.
The developer of this two-question approach, psychologist Tilmann Habermas, wasn’t focused on people who had experienced trauma. Habermas, now at Goethe University Frankfurt, wanted to understand how adolescents develop a narrative identity and then sustain that sense of self over time.
In 2003, Habermas launched a study that would follow participants for up to 16 years. Participants came into the lab every four years and dictated their life story in roughly 20-minute increments, using the two-task format I tried with Tran. Habermas analyzed the resulting transcripts line by line, coding them for emotion, tense, transitions and other features.
With few psychologists at the time studying autobiography as a window into the mind, Habermas turned to theorists from other fields for guidance. “After I read psychology, I read narratology, literary theory, linguistics, social linguistics,” he says. “I had to steal … all these concepts from the other areas.”
One of Habermas’ questions was how people retain their sense of self in the face of life’s many disturbances, such as divorce, illness, job loss or moving to a new location.
Philosophers have been puzzling over this question for millennia. “Your body has changed. Your experiences have changed. Your knowledge has changed. And yet, people generally think of themselves as being the same person … in the past and future,” says psychologist Yosef Sokol of Touro University in New York City. “That’s a hard problem.”
This general belief in self-continuity appears universal, even though how it is constructed may differ across cultures. In the third wave of Habermas’ long-term study, when 150 participants were ages 16, 20, 28, 44 and 69, Habermas and Camia, who joined Habermas’ lab in 2009, also analyzed the transcripts for a type of thinking called autobiographical reasoning. This reasoning links the self across space and time.
“Autobiographical reasoning is this conscious reflection. How did my past impact me? How did I become the person I am today, and what does it mean for my future?” Camia says. Such reasoning tends to stem from change, she adds. “If there is perfect stability in life, you don’t do a lot of autobiographical reasoning … it’s the changes and the crises that compel meaning-making.”
The researchers divvied such reasoning into eight categories, such as turning points, lessons learned, generalized insights and using an event to explain a change in personality.
Participants also filled out two surveys. One survey summed up the number of big life changes experienced over the previous four years. The other gauged self-continuity, with participants rating the truth of statements such as, “When I look at pictures of myself four years back, it feels a little unfamiliar” and “I have the feeling that at the core I am the same person I was four years ago.”
Researchers then compared the three variables: autobiographical reasoning, levels of life change and sense of self-continuity. As expected, levels of autobiographical reasoning showed no discernible pattern among participants who experienced few changes in life, the team reported in 2015 in Memory.
But when the researchers zoomed in on the quarter of participants reporting the greatest level of change, more autobiographical reasoning came with higher levels of self-continuity. “Constructing continuity in the life story buffers against the effect of change in your life,” Habermas says. Other teams have made similar findings. Most disruptions, however, do not rise to the level of trauma — such as that experienced by Tran. Several years later, Camia would study how traumatic events, notably being forced to flee one’s home and the resulting isolation and bereavement, affect people’s sense of self.
Trauma messes with our sense of time “What does war change first? One’s sense of time, one’s sense of space,” said Ukrainian writer Serhiy Zhadan in an October speech translated to English in the online magazine LitHub.
Zhadan speaks from experience. But the idea that trauma disrupts time perception is also borne out by research. Researchers have found that emotions frequently dictate whether we experience time as passing fast or slow. And traumatic events, which come with intense emotions, can cause people to experience time in slow motion, researchers reported in 2012 in Frontiers in Psychology.
During a car accident, for instance, a person’s whole body is ready to act, says Marc Wittmann, a psychologist with the Institute for Frontier Areas of Psychology and Mental Health in Freiburg, Germany. “Your inner workings, your processing, is speeded up. Relative to that, your outside slows down.”
What’s more, says health psychologist Alison Holman of the University of California, Irvine, in that moment or moments of crisis, you do not think about the past or future. All that matters is survival.
Zhadan speaks directly to this idea in his speech: “People in a war-torn space try not to plan for the future or think too much about what the world will be like tomorrow. What’s happening to you here and now is all that matters, just the people and things that will be with you tomorrow morning — tops. That’s if you survive and wake up.”
That narrow focus can wreak havoc on mental health. “[When] that present moment is so intense that it sears into your mind … it may set up the likelihood that you will have a hard time moving past it,” Holman says. “The past never passes.”
Such breakdowns in time can show up in language, particularly among those most severely affected by trauma. For instance, Habermas and his team compared the speech patterns of 14 women diagnosed with post-traumatic stress disorder following a singular shocking event, such as physical or sexual abuse, and 14 women without such a diagnosis. The women with PTSD used more immersive language. They quoted people directly and spoke of the past as if it was ongoing, says Habermas, who reported the findings in 2014. “Instead of saying, ‘He hit me,’ they would say, ‘He hits me.’ ”
This immersive language dominates Tran’s narration. She is “carrying” her little sister. Her mother is “coming” back to the violent man. She is “walking many kilometers to school in the rain and then opening up my newspaper-wrapped wet and warm tomato sandwiches. They’re so wet, but I’m so hungry that I know I have to eat them otherwise I’ll never make the walk back.”
And always there, her mother’s voice: “Just trust me, Trish. Just trust me.”
“I don’t think I will ever forget those words,” Tran says.
Traumatized people can lose their life story Tran remembers her mother’s words exactly, but other details of the abuse she experienced as a child are fuzzier. That’s common among people who experience trauma. People with trauma “have both an excess and depletion of memory,” says cognitive neuroscientist Elisa Ciaramelli of the University of Bologna in Italy.
How memory changes among trauma survivors remains controversial, write the authors of a 2021 opinion piece in Frontiers in Psychology. But mounting evidence suggests that people tend to remember stressful memories in detail. As the mind fixates on those traumatic memories, memories unrelated to the trauma seem to fade, while new memories fail to register.
For example, when asked to describe memories associated with a specific word, such as “beach,” people who do not have PTSD offer detailed reports, describing what they were wearing, what they said and who they were with, Ciaramelli says. People who have PTSD, on the other hand, typically provide general memories with little color.
Other memories can’t find a foothold. In one study, researchers asked 52 participants — 26 people with PTSD and 26 people who had experienced trauma but not developed PTSD — to keep a diary recording their memories over the course of a week. Participants also responded to questions about the memory, such as whether or not it related to their trauma, how central it was to their current life and how far away in time the memory felt.
Participants without PTSD recorded an average of 21.4 memories across the week while participants with PTSD recorded an average of just 11 memories, the team reported in 2017 in Clinical Psychological Science. The PTSD participants had more trauma-related memories than the non-PTSD group.
Tran recognizes this paucity of detail in her own life story. “My memories are lightbulb memories,” she says. “They are always attached to significant events like trauma or happy times. I may have 57 years of life, but you could truncate them into a chapter.”
Everyone’s memory has imprecision of course. That imprecision allows us to cut extraneous details and make sense of our story. The traumatized person’s relative lack of memories, though, both in clarity and quantity, means they struggle to construct a cohesive narrative of their past and to envision themselves moving forward.
“Ten years ago, people have found that the same brain regions that are activated and are necessary for remembering the past are also necessary to imagine the future,” Ciaramelli says. “We need memories to imagine the future.”
Camia’s work with refugees shows what can happen to the sense of self as people struggle and fail to reconcile a traumatic experience with the larger story of their life. Her central aim, which built on work with Habermas, was to see if the same autobiographical arguments people used to buffer against life’s everyday changes could help those facing traumatic disruptions. She and Rida Zafar, a psychology student at New York University Abu Dhabi, recruited 31 refugees living in Germany and asked them to narrate their life stories, plus fill out the life change and self-continuity surveys used in the 2015 study.
Among the 16 refugees who experienced relatively less change since arriving in Germany, such as fewer upheavals in relationships and fewer moves, more autobiographical reasoning did correlate with higher self-continuity, the team reported in 2021 in Frontiers in Psychology. Refugees who experienced high change also used autobiographical reasoning, but their sense of self-continuity remained low.
These individuals cannot settle their trauma, Camia explains, so their reckoning with the past leads not to resolution but rumination. They are stuck.
Therapy could restore the future self For most of her adult life, Tran grappled with that sense of stagnation. “My identity was rooted in the past, and I couldn’t move forward,” she says. “Time was this eternal loop. Every time a problem came up, it felt like a replication of a past problem. I couldn’t see that I could change anything.”
Over and over again, unable to envision a viable escape, Tran tried to kill herself.
Suicide attempts serve as the clearest signal that a person’s future has gone blank, says Sokol, the psychologist at Touro University. The thinking here is intuitive. “If you think you have a meaningful life into the future, you’re not going to kill yourself,” he says.
Conventional therapies for treating people struggling with suicidal thinking often fail to meet their needs because the therapies do not directly address people’s future self, Sokol and his team wrote in 2021 in the Journal of Cognitive Psychotherapy. For instance, dialectical behavior therapy emphasizes focusing on the present to cope with stress and manage emotions. Narrative therapy likewise aims to help patients incorporate traumatic and other events into a continuous timeline, but focuses on linking past to present, not present to future.
So Sokol developed a therapy that incorporates elements of past- and present-oriented treatments but prioritizes future thinking. It’s known as continuous identity cognitive therapy. His goal is to help military veterans struggling with mental illness re-create the plot in the mental timeline of their lives, to answer those foundational questions: Who am I? Where do I go from here?
Sokol tested an initial version of the therapy in a four-week pilot study with 17 veterans. The program contains many work-arounds for participants struggling to access or make sense of their memories. The specific memory is less important than the larger story, or the broader values contained within that memory, Sokol says. “I have all sorts of techniques to help people tap into something that they find important, meaningful.”
In the first week, participants are asked to define their core values. The hope is that those values, rather than specific past events, will form the core of a person’s life story. To get to that core, participants review negative and positive experiences from their past and identify choices they made.
Many veterans struggle with what are called moral injuries — choices they made that don’t seem to align with who they wish to be, Sokol says. So veterans push those memories away. With the values approach, he hopes participants can start to see that they made the best choices they could under challenging circumstances. One way to access those values is to have participants identify people they admire, and the values those people embody. Participants can then use those people’s experiences to identify their own core values.
The focus of the second week shifts to the future. Participants assemble possible futures by reflecting on how life might play out if they work with, or against, their stated values. Participants also actively construct self-continuity. For instance, they write letters to themselves across different time points, such as from their present self to their future self or vice versa.
In week three, participants learn to differentiate between external life stories, the series of events outside their control, and internal life stories made up of choices in line with their stated values. By week four, participants should be able to visualize their future self overcoming an issue that their present self faces. Tran came across Sokol’s research while embarking on her own journey to healing. That process began when Tran realized how her trauma was hurting the people she loved most. “I’m just causing my children and everybody near and dear trauma. I’m going to take [suicide] off the table,” she eventually realized. “This is not my pathway anymore. If it’s not my pathway, what am I going to do with the next 50 years of my life?”
Tran felt lost. So she dug into research on trauma survivors, eventually stumbling upon Sokol’s project. She was moved by the idea that participants did not have to reconstruct the past to build a new future. “This is true. My soul knows this to be true,” she remembers thinking.
Tran, who is also a trainer with DISCHARGED, a nonprofit organization that provides peer group support for people experiencing suicidal thoughts, and an occasional adviser to researchers writing about suicide, reached out to Sokol and offered to help him make the language used in his program more sensitive to people who have experienced trauma. For instance, she suggested changing references to “you” to “we” to give people a greater sense of belonging and agency. The two still work together.
Research on the therapy remains limited to Sokol’s lab, but initial results are promising. The pilot study showed that the program decreased previously reported levels of suicidal ideation and depression. Those levels stayed low one month after completion. Now Sokol has received a five-year, $1.1 million grant from the U.S. Department of Veterans Affairs to scale up the program and eventually roll out a randomized controlled trial. In its newer iteration, the program will run for three months instead of one.
With input from Tran and veterans in the program, Sokol made another substantial modification to the pilot program. Participants will now identify how their own story intersects with the stories of other people in their lives. That addition makes sense to Tran, who has become engrossed in research showing the intergenerational nature of trauma. She now sees her life as part of a larger story with many characters, each on their own often troubled journey.
She says her story will always be truncated. But even without a clean narrative arc, she has managed to sever time’s eternal loop. “You can change your relationship with your past experiences in a way that makes living a future possible,” Tran says.
