A teenage girl climbed into an underground cave around 13,000 years ago. Edging through the ink-dark chamber, she accidentally plunged to her death at the bottom of a deep pit.

Rising seas eventually inundated the cave, located on Central America’s Yucatán Peninsula. But that didn’t stop scuba divers from finding and retrieving much of the girl’s skeleton in 2007.

“First Face of America,” a new NOVA documentary airing February 7 on PBS, provides a closeup look at two dangerous underwater expeditions that resulted in the discovery and salvaging of bones from one of the earliest known New World residents, dubbed Naia.
The program describes how studies of Naia’s bones (SN: 6/14/14, p. 6) and of genes from an 11,500-year-old infant recently excavated in Alaska have generated fresh insights into how people populated the Americas. Viewers watch anthropologist and forensic consultant James Chatters, who directed scientific studies of Naia’s remains, as he reconstructs the ancient teen’s face and charts the lower-body injuries that testify to what must have been a rough life.
In one suspenseful scene, cameras record Chatters talking with scuba divers shortly before the divers descend into the submerged cave to collect Naia’s bones. The scientist describes how thousands of years of soaking in seawater have rendered the precious remains fragile. He uses a plaster cast of a human jaw to demonstrate for scuba diver Susan Bird how to handle Naia’s skull so that it stays intact while being placed in a padded box. Bird’s worried expression speaks volumes.

“On the day of the dive, there was so much tension, so many people on the verge of freaking out,” Bird recalls in the show. When the divers return from their successful mission, collective joy breaks out.
The scene then shifts to a lab where Chatters painstakingly re-creates what Naia looked like. Asian-looking facial features raise questions about how the ancient youth ended up in Central America. That’s where University of Alaska Fairbanks anthropologist Ben Potter enters the story. In 2013, Potter and colleagues excavated the remains of two infant girls at an Alaskan site dating nearly to Naia’s time. Analysis of DNA recovered from one of the infants , described in the Jan. 11 Nature , supports a scenario in which a single founding Native American population reached a land bridge that connected northeast Asia to North America around 35,000 years ago. As early as 20,000 years ago, those people had moved into their new continent, North America. Naia’s face reflects her ancestors’ Asian roots.
In tracing back how people ended up in the Americas, NOVA presents an outdated model of ancient humans moving out of Africa along a single path through the Middle East around 80,000 years ago. Evidence increasingly indicates that people started leaving Africa 100,000 years ago or more via multiple paths (SN: 12/24/16, p. 25). That’s a topic for another show, though. In this one, Naia reveals secrets about the peopling of the Americas with a lot of help from intrepid scuba divers and state-of-the-art analyses. It’s fitting that a slight smile creases her reconstructed face.

One of the strangest things about growing a human being inside your body is the alien sensation of his movements. It’s wild to realize that these internal jabs and pushes are the work of someone else’s nervous system, skeleton and muscles. Someone with his own distinct, mysterious agenda that often includes taekwondoing your uterus as you try to sleep.

Around the 10-week mark, babies start to bend their heads and necks, followed by full-body wiggles, limb movement and breathing around 15 weeks. These earliest movements are usually undetectable by pregnant women, particularly first-timers who may not recognize the flutters until 16 to 25 weeks of pregnancy. These movements can be exciting and bizarre, not to mention uncomfortable. But for the developing baby, these kicks are really important, helping to sculpt muscles, bones and joints.
While pregnant women can certainly sense a jab, scientists have largely been left in the dark about how normal fetuses move. “It’s extremely difficult to investigate fetal movements in detail in humans,” says Stefaan Verbruggen, a bioengineer formerly at Imperial College London who recently moved to Columbia University in New York.

Now, using relatively new MRI measurements of entire fetuses wiggling in utero, researchers have tracked these kicks across women’s pregnancies. The results, published January 24 in the Journal of the Royal Society Interface, offer the clearest look yet at fetal kicking and provide hints about why these moves are so important.
Along with bioengineer Niamh Nowlan, of ICL, and colleagues, Verbruggen analyzed videos of fetal kicks caught on MRI scans. These scans, from multiple pregnant women, included clear leg kicks at 20, 25, 30 and 35 weeks gestation. Other MRI scans provided anatomical details about bones, joints and leg sizes. With sophisticated math and computational models, the researchers could estimate the strengths of the kicks, as well as the mechanical effects, such as stresses and strains, that those kicks put on fetal bones and joints.
Kicks ramped up and became more forceful from 20 to 30 weeks, the researchers found. During this time, kicks shifted the wall of the uterus by about 11 millimeters on average, the team found. But by 35 weeks, kick force had declined, and the uterus moved less with each kick, only about 4 millimeters on average. (By this stage, things are getting pretty tight and tissues might be stretched taut, so this decrease makes sense.) Yet even with this apparent drop in force, the stresses experienced by the fetus during kicks kept increasing, even until 35 weeks. Increasing pressure on the leg bones and joints probably help the fetus grow, the researchers write.

Other work has found that the mechanical effects of movement can stimulate bone growth, which is why weight-bearing exercises, such as brisk walking and step aerobics, are often recommended for people with osteoporosis. In animal studies, stationary chick and mouse fetuses have abnormal bones and joints, suggesting that movement is crucial to proper development.

The results highlight the importance of the right kinds of movements for fetuses’ growth. Babies born prematurely can sometimes have joint disorders. It’s possible that bone growth and joints are affected when babies finish developing in an environment dominated by gravity, instead of the springy, tight confines of a uterus. Even in utero position might have an effect. Head-up breech babies, for instance, have a higher risk of a certain hip disorder, a link that hints at a relationship between an altered kicking ground and development. In fact, the researchers are now looking at the relationship between fetal movements and skeletal stress and strain in these select groups.

Mechanical forces in utero might have long-lasting repercussions. Abnormal joint shapes are thought to increase the risk of osteoarthritis, says Verbruggen, “which means that how you move in the womb before you’re even born can affect your health much later in life.”

There’s a lot more work to do before scientists fully understand the effects of fetal movements, especially those in less than ideal circumstances. But by putting hard numbers to squirmy wiggles, this new study is kicking things off right.

It’s another record for SpaceX. At 3:50 p.m. Eastern on February 6, the private spaceflight company launched the Falcon Heavy rocket for the first time.

The Heavy — essentially three SpaceX Falcon 9 rocket boosters strapped together — is the most powerful rocket launched since the Saturn V, which shot astronauts to the moon during the Apollo program. SpaceX hopes to use the Heavy to send humans into space. The company is developing another rocket, dubbed the BFR, to eventually send people to Mars.
Another first for this launch: the synchronized return of two of the boosters. (The third, from the center core, didn’t descend properly, and instead of landing on a droneship, it hit the ocean at 300 mph.) Part of SpaceX’s program is to reuse rockets, which brings down the cost of space launches. The company has successfully landed the cores of its Falcon 9 rockets 21 times and reflew a rocket six times. The company landed a previously used rocket for the first time in March.

But the cargo for today’s launch is aimed at another planet. The rocket carried SpaceX CEO Elon Musk’s red Tesla Roadster with “Space Oddity” by David Bowie playing on the stereo. It is now heading toward Mars.

“I love the thought of a car drifting apparently endlessly through space and perhaps being discovered by an alien race millions of years in the future,” Musk tweeted in December.
Editor’s note: This story was updated on February 7 to update the status of the booster landings, and again on February 9 to correct the rocket that SpaceX hopes to use to send people to Mars. The company intends to use its BFR rocket, not the Falcon Heavy.

Bedbugs leave a lasting legacy.

Their poop contains a chemical called histamine, part of the suite of pheromones that the insects excrete to attract others of their kind. Human exposure to histamine can trigger allergy symptoms like itchiness and asthma. (Our bodies also naturally release histamine when confronted with an allergen.) Histamine stays behind long after the bedbugs disappear, scientists report February 12 in PLOS ONE.

Researchers from North Carolina State University in Raleigh collected dust from apartments in a building with a chronic bedbug infestation. After a pest control company treated the apartments by raising the temperature to a toasty 50° Celsius, the researchers sampled the dust again. They compared those two sample groups with a third, from area homes that hadn’t had bedbugs for at least three years.

Dust from the infested apartments had levels of histamine chemical that were 22 times as much as the low amount found in bedbug-free houses, the researchers found. And while the heat treatment got rid of the tiny bloodsuckers, it didn’t lower the histamine levels.

Future pest control treatments might need to account for bedbugs’ long-term effects.

AUSTIN, Texas — An analysis of the metals in dozens of Picasso’s bronze sculptures has traced the birthplace of a handful of the works of art to the outskirts of German-occupied Paris during World War II.

This is the first time that the raw materials of Picasso’s sculptures have been scrutinized in detail, conservation scientist Francesca Casadio of the Art Institute of Chicago said February 17 at the annual meeting of the American Association for the Advancement of Science. And the elemental “fingerprints” help solve a mystery surrounding the sculptures’ origins.
“In collaboration with curators, we can write a richer history of art that is enriched by scientific findings,” Casadio said.

Casadio and colleagues from the Art Institute of Chicago and Northwestern University in Evanston, Ill., studied 39 bronzes in the collection of the Picasso Museum in Paris. The team used a portable X-ray fluorescence spectrometer to record the amount of copper, tin, zinc and lead at several points on each sculpture.
Based on the percentage of tin versus zinc in the bronze, “we found that there are compositional groups that relate to a specific foundry,” Casadio said. Seventeen sculptures had a foundry mark on them, so the researchers could relate metal mixes to specific foundries.
But seven sculptures lack foundry marks. Based on their composition, researchers pegged five to a specific foundry — that of Émile Robecchi, a craftsman whose workshop sat in the southern outskirts of Paris. Original invoices from the foundry surfaced two years ago and revealed when some of the pieces were cast. For instance, the description, weight and size written on one invoice confirmed that the bronze of Tête de femme de profil (Marie­Thérèse) — a portrait of one of Picasso’s mistresses originally sculpted in plaster in 1931 — was cast at the foundry in February 1941.
At that time, the war had been under way for years and the Germans had just occupied Paris. Picasso worried that his fragile plaster sculptures could be easily destroyed and sought to have them cast in bronze.

The team’s analysis also found two distinct mixtures of bronze that came out of the Robbechi foundry. That difference makes sense in the context of 1940s occupied Paris, when the Germans instituted laws requiring that people turn in certain metals to go toward war efforts, Casadio said.

“A lot of [foundries’] archives are incomplete or nonexistent,” Casadio said. The new analysis “reinforces why it’s really important to collaborate and how science adds the missing piece of the puzzle.”

Chile’s Atacama Desert is so dry that some spots see rain only once a decade. Salt turns the sandy soil inhospitable, and ultraviolet radiation scorches the surface. So little can survive there that scientists have wondered whether snippets of DNA found in the soil are just part of the desiccated skeletons of long-dead microbes or traces of hunkered-down but still living colonies.

A rare deluge has solved that mystery. Storms that dumped a few centimeters of rain on the Atacama in March 2015 — a decade’s worth in one day — sparked a microbial superbloom, researchers report February 26 in Proceedings of the National Academy of Sciences.
That storm initially threw a wrench into plans for scientists to get a snapshot of microbial life under normal, hyperarid conditions in the Atacama. “But in the end, it came back as a lucky stroke,” says study coauthor Dirk Schulze-Makuch, an astrobiologist at the Technische Universität Berlin. He and his colleagues drove mining vehicles into the desert to collect soil samples just a few weeks after the storm, and then returned again in 2016 and 2017 to track changes as the moisture dissipated.

The team found microbes — a mix of extremophile archaea, bacteria and fungi — that were tolerant of desiccation, salinity and UV radiation. The kinds of species were fairly consistent across sampling sites, which suggests there’s something of a native microbial community that can survive in this salty sand by going dormant between periods of moisture, says Schulze-Makuch.

Schulze-Makuch and his colleagues also found evidence for enzymes that are by-products of cellular metabolism. And traces of ATP, the molecule that cells use for energy, lingered inside cells. Those markers of life were the most bountiful at the first sampling time, and then declined as the soil dried out again.

Collectively, it’s evidence that microbes aren’t just dying and leaving their DNA behind in the Atacama — they’re laying low to live another day. That’s encouraging to Schulze-Makuch: He’s interested in the Atacama as a proxy for conditions on Mars.
Armando Azua-Bustos, an astrobiologist at the Centro de Astrobiología in Madrid who was not part of this study, agrees. “If we’re finding that, on Earth, truly dry places are still inhabited,” he says. “That opens the door to finding life elsewhere in the universe.”

LOS ANGELES — Quantum computers are bulking up.

Researchers from Google are testing a quantum computer with 72 quantum bits, or qubits, scientists reported March 5 at a meeting of the American Physical Society — a big step up from the company’s previous nine-qubit chip.

The team hopes to use the larger quantum chip to demonstrate quantum supremacy for the first time, performing a calculation that is impossible with traditional computers (SN: 7/8/17, p. 28), Google physicist Julian Kelly reported.
Achieving quantum supremacy requires a computer of more than 50 qubits, but scientists are still struggling to control so many finicky quantum entities at once. Unlike standard bits that take on a value of 0 or 1, a qubit can be 0, 1 or a mashup of the two, thanks to a quantum quirk known as superposition.

Nicknamed Bristlecone because its qubits are arranged in a pattern resembling a pinecone’s scales, the computer is now being put through its paces. “We’re just starting testing,” says physicist John Martinis of Google and the University of California, Santa Barbara. “From what we know so far, we’re very optimistic.” The quantum supremacy demonstration could come within a few months if everything works well, Martinis says.

Google is one of several companies working to make quantum computers a reality. IBM announced it was testing a 50-qubit quantum computer in November 2017 (SN Online: 11/10/17), and Intel announced a 49-qubit test chip in January.

And the winner is in. Of the roughly 34,000 submissions sent in by the public, NASA has finally chosen an official nickname for the New Horizons spacecraft’s next destination: Ultima Thule.

New Horizons is scheduled to visit the tiny Kuiper Belt object on New Year’s Day 2019. NASA announced in November that it was seeking public input for a catchier name than the object’s existing moniker: 2014 MU69. Submissions varied wildly, ranging from the mythological Olympus to the much less grandiose Nubbin, defined as a “small lump or residual part” (SN Online: 11/7/17).

The final choice, Ultima Thule (pronounced “thoo-lee”), was announced March 13. It means “beyond the borders of the known world.” The nickname is a nice fit since the object will be the most distant solar system body ever visited.

After the flyby, NASA will submit a formal name to the International Astronomical Union based on whether Ultima Thule is a single object, a binary pair or a multi-object system.

Honeybees and bumblebees have a way to resist toxic compounds in some widely used insecticides.

These bees make enzymes that help the insects break down a type of neonicotinoid called thiacloprid, scientists report March 22 in Current Biology. Neonicotinoids have been linked to negative effects on bee health, such as difficulty reproducing in honeybees (SN: 7/26/16, p 16). But bees respond to different types of the insecticides in various ways. This finding could help scientists design versions of neonicotinoids that are less harmful to bees, the researchers say.
Such work could have broad ramifications, says study coauthor Chris Bass, an applied entomologist at the University of Exeter in England. “Bees are hugely important to the pollination of crops and wild flowers and biodiversity in general.”

Neonicotinoids are typically coated on seeds such as corn and sometimes sprayed on crops to protect the plants from insect pests. The chemicals are effective, but their use has been suspected to be involved in worrisome declines in numbers of wild pollinators (SN Online: 4/5/12).

Maj Rundlöf of Lund University in Sweden helped raise the alarm about the insecticides. In 2015, she reported that neonicotinoid-treated crops reduced the populations of bees that fed from the plants. Rundlöf, who was not involved with the new study, says the new research is important because it clarifies differences between the insecticides. “All neonicotinoids are not the same,” she says. “It’s a bit unrealistic to damn a whole group of pesticides.”

Bass and his colleagues, which include scientists from Bayer, one of the main producers of neonicotinoids, investigated resistance to thiacloprid by looking at bees’ defense systems. The team focused on enzymes known as P450s, which can metabolize toxic chemicals, breaking them down before they affect the bee nervous system. The researchers used drugs to inhibit groups of P450 enzymes. When the family enzymes called CYP9Q was inhibited, bees became 170 times as sensitive to thiacloprid, dying from a much smaller dose, the researchers found. Discovering the enzymes’ protective power could lead to more effective ways to simultaneously avoid harming bees and help crops.
“We live in an era that uses pesticides,” Rundlöf says. “We need to figure out the ones that are safest.”

Mass: About 60 billion suns’ worth.

Location: The galaxy NGC1052–DF2, about 65 million light-years from Earth.

An unusual galaxy is surprisingly lacking in dark matter, scientists report March 28 in Nature.

In typical galaxies, normal matter is swamped by dark matter, an unidentified invisible substance that makes up most of the matter in the universe. The existence of dark matter explains the unexpectedly fast speeds at which stars swirl around galaxies, and how galaxies move within clusters.
But one galaxy, NGC1052–DF2, appears to have less dark matter than normal matter, or potentially none at all. Given its mass — it holds stars with about 200 million times the mass of the sun — it would be expected to have about 300 times as much dark matter as normal matter. That adds up to about 60 billion times the sun’s mass in missing dark matter.

Using observations from several telescopes, Yale University astronomer Pieter van Dokkum and colleagues studied 10 bright clumps of stars within the galaxy, known as globular clusters, and measured their velocities. The more mass there is in the galaxy, the faster the clusters should move around it. So if dark matter were present, the clusters should cruise at a relatively rapid clip. Instead, the clusters were moving slowly, indicating a dark matter–free zone.
In most galaxies, stars move faster than naïvely expected, which suggests dark matter lurks within them, providing an extra source of mass. Most physicists believe dark matter is an undetected type of particle. But some think that the hint of extra matter might be a mirage, caused by an incomplete understanding of the workings of gravity. These researchers favor a theory known as modified Newtonian dynamics, or MOND (SN: 3/31/07, p. 206), which adjusts the rules of gravity to make sense of stars’ motions, without requiring any new, elusive particles.

The new study, says van Dokkum, bolsters the idea that dark matter is real, instead of an illusion. “Until now, whenever we saw a galaxy, we also saw dark matter,” says van Dokkum. “We didn’t know for sure whether dark matter and galaxies were two separable things.”

Because MOND proposes tweaking the laws of physics, then — if correct — its effects should be felt in every galaxy across the cosmos. That makes it hard for MOND to explain the unusually slow speeds of the star clusters in NGC1052–DF2.

“It’s intriguing, but it’s not something I’m going to lose sleep over,” says Stacy McGaugh, an astrophysicist at Case Western Reserve University in Cleveland. He studies MOND and thinks the theory might still be able to explain this galaxy. That’s because NGC1052–DF2 is nestled close to another galaxy. That other galaxy could alter MOND’s predictions, perhaps explaining why the star clusters move slowly. The effect of that proximity needs to be taken into account to determine if MOND can explain the observations, he says.

Still, McGaugh acknowledges that NGC1052–DF2 is problematic for MOND. But it is also problematic for the standard dark matter picture, he says, as it’s not clear how such a galaxy could form in the first place. Most galaxies are thought to form around clumps of dark matter, so a galaxy devoid of the stuff is hard to explain.

NGC1052–DF2 is unusual in other ways. It’s a faint, ghostly blob known as an ultradiffuse galaxy. Although about the same volume as the Milky Way, NGC1052–DF2 contains many fewer stars. Scientists are struggling to understand why such galaxies look so different from most others (SN: 12/10/16, p. 18). Finding an ultradiffuse galaxy without dark matter further complicates the puzzle.

If scientists can explain how the galaxy formed, it might improve understanding of the properties of dark matter. “In physics we always want to find really extreme laboratories to test theories and ideas,” says astrophysicist James Bullock of the University of California, Irvine. This galaxy is extreme indeed.