Research Highlights

Our pick of the latest scientific literature

An adult meerkat protecting two pups while sitting outside burrow in the Namib Desert

An adult meerkat watches all the pups in its social circle, both its own and others'. Credit: Paul Souders/Getty

Animal behaviour

The furry carnivores that are the ultimate altruists

Meerkats help all those around them, regardless of the strength of familial ties.

Meerkats are helpful to all their group members because they are related to every animal in their social circle, according to a study of the adorably alert desert mammals.

Evolutionary theory predicts that animals will help only their own kin. Over time, such altruism is advantageous, because of the genetic relationship between the helper and the helped: the assistance allows the receiver to have, on average, more offspring than they would otherwise. But for some social animals, it isn’t easy to keep track of who is related to whom.

To explore altruistic behaviour in the species, Chris Duncan at the University of Cambridge, UK, and his colleagues studied 25 years of data on 1,347 meerkats (Suricata suricatta) in South Africa’s Kalahari Desert. Meerkats babysat and fed one another’s offspring; took turns guarding the group; and dug communal burrows. Analysis showed that, for the most part, these actions were undertaken without regard to how closely related the beneficiary was to the helper.

The researchers suspect that because all members of a meerkat group are closely related, it makes sense for them to be indiscriminately helpful.

Residents wade through flood waters at their home days after Hurricane Maria made landfall in Puerto Rico

The torrential rainfall that flooded Puerto Rico during Hurricane Maria in 2017 has been attributed, in part, to warming of the ocean and atmosphere. Credit: Alex Wroblewski/Getty

Climate change

Hurricane Maria’s catastrophic rains are linked to global warming

The violent storm dropped more than 1 metre of rain at one site in Puerto Rico in 24 hours.

Climate change is partly to blame for the heavy rains of Hurricane Maria, which devastated Puerto Rico in 2017.

The storm drenched the island, causing flooding, landslides and, owing to fierce winds, a near-total wipeout of electricity and communications. One location measured more than 1 metre of rainfall in 24 hours.

Data from 35 weather stations show that Maria was the wettest hurricane to hit Puerto Rico since detailed records began in 1956, say David Keellings at the University of Alabama in Tuscaloosa and José Hernández Ayala at Sonoma State University in Rohnert Park, California. Maria’s total rainfall was higher than that of every one of the other 128 storms that arrived during that period, including 1998’s destructive Hurricane Georges.

The scientists’ statistical analysis suggests that, as a result of climate change, extreme rains like those seen during Maria are nearly five times more likely to hit Puerto Rico today than they were in the 1950s. This is because storms become wetter as the atmosphere and ocean warm.

Coiled Western Diamondback Rattlesnake

A western diamondback rattlesnake that was eaten raw and intact is the probable source of reptile bones in a sample of prehistoric human poo. Credit: Don Grall/Getty

Archaeology

A viper’s tooth in ancient human poo hints at snake-eating rituals

Prehistoric feces found in Texas includes scales, bones and a fang.

Everybody poos, but not all poos are alike. An ancient piece of dehydrated human dung contains the bones, scales and a fang of a venomous snake — an indication that the reptile might have been eaten whole, likely as part of a ritual event.

Ancient peoples of North America routinely ate snakes, even poisonous ones, usually after they removed the scales and head. But when Elanor Sonderman at Texas A&M University in College Station and her colleagues analysed a 1,500-year-old sample of human dung found in Texas, they identified 22 snake bones, 48 snake scales and a 1-centimetre-long snake fang. This suggests that the reptile, likely a western diamondback rattlesnake (Crotalus atrox), was eaten whole and unskinned.

Many peoples, including Indigenous groups in the southwestern United States, worshipped snakes, leading the team to propose that the animal was consumed during a ceremony or ritual. The feces also contain the remains of a small rodent, consumed whole and apparently raw. But whether the rodent had been the human’s or the snake’s meal is unclear, the researchers say.

A nursing worker takes care of new-born babies at a hospital in China

Newborn babies snuggle together at a hospital in China. More girls have gone missing over the past half-century in this nation than in any other country. Credit: VCG/Getty

Society

Millions of girls go ‘missing’ as a medical procedure takes hold

The advent of sex-selective abortion has ushered in changes in the sex ratio of newborns.

Some 23 million girls worldwide were never born because of the use of sex-selective abortions during the past half-century.

China and India account for the vast majority of these ‘missing’ girls, with 11.9 million and 10.6 million, respectively.

Fengqing Chao at the National University of Singapore and her colleagues drew on birth certificates, census data and other sources to compile a database of sex ratios at birth in more than 200 countries or other jurisdictions. Most of the information dated to 1950 or later.

For each country, the team used the decades’ worth of data to estimate baseline levels of male–female birth ratios, which ranged from 1.013 in Namibia and Zambia to 1.081 in Hong Kong.

After the advent of sex-selective abortion in the 1970s, the male–female birth ratio changed significantly in 12 nations. China’s reached 117.9 boys per 100 girls in 2005.

Some countries’ ratios have since dropped back to normal ranges. But, as of 2017, several nations, including China and Armenia, still had more than 110 boys born per every 100 girls, according to the team’s estimates.

Downstream view of terrace development along upper North Fork Toutle River channel

The North Fork Toutle River in Washington wends through rock and sediment deposited by the 1980 eruption of Mount St Helens. Credit: Kurt Spicer/USGS

Hydrology

How a river returns to life after a cataclysmic volcanic eruption

Entombed by debris nearly 40 years ago, a river in the northwestern United States runs again.

The eruption of Mount St Helens in 1980 unleashed an avalanche of debris into a river in Washington. Decades of monitoring now detail the river channel’s unexpectedly complex evolution — and hint that abnormally high volumes of sediment will continue to sweep downstream indefinitely.

The eruption buried the North Fork Toutle River valley in 2.5 billion cubic metres of mud and rock. The debris has sent massive amounts of sediment downstream, prompting a sediment-control campaign that included constructing a 600-metre-wide dam across the river.

For the past 39 years, researchers have regularly surveyed the route the river is cutting through the debris, providing a rare look at how a waterway re-establishes itself in a transformed landscape. The data show that the river has scoured and filled its bed, and widened and narrowed its channel, in complex and unexpected ways, says a team led by Jon Major at the US Geological Survey in Vancouver, Washington.

The river’s activity hints that authorities will need to manage the system’s sediment “for the foreseeable future”, the authors write.

Cross-sectional scanning electron microscopy image of the 3DGraphene foam with a homogeneous and highly porous structure.

Graphene foam keeps its elasticity when all other materials are frozen stiff. Credit: K. Zhao <i>et al./Sci. Adv.</i>

Materials science

The solid that remains flexible at temperatures close to absolute zero

A spongy form of graphene can also maintain its resilience when subjected to extreme heat.

The wonder-material graphene has gained yet another superlative: exceptional flexibility at temperatures at which everything else is frozen solid.

Graphene consists of a single layer of carbon atoms, and is the thinnest and strongest material known, the best at conducting both heat and electric current, and almost totally transparent to wavelengths of light ranging from the ultraviolet to the infrared. Pulickel Ajayan at Rice University in Houston, Texas, Yongsheng Chen at Nankai University in Tianjin, China, and their colleagues made graphene foam and deformed it repeatedly. The foam’s elasticity remained essentially unchanged at temperatures ranging from -269°C (4 kelvin) to 1000°C. Silicone rubber, by contrast, becomes hard and brittle at -55°C and melts at 300°C.

The researchers also found that the foam can stretch to almost twice its length and return to its original shape even when chilled to -269°C, the temperature at which helium liquefies. Every other known material becomes completely inflexible when chilled to a few tens of degrees below 0°C. Graphene’s elasticity over a wide temperature range could make it useful in extreme environments such as outer space.

Gaia’s all-sky view of our Milky Way Galaxy and neighbouring galaxies

The Milky Way, captured here by the Gaia spacecraft, had a massive growth spurt that began some five billion years ago. Credit: ESA/Gaia/DPAC

Astronomy and astrophysics

The cosmic drama that helped to build the Milky Way

Stellar baby boom added a slew of stars to the Galaxy’s disk.

A burst of star formation that peaked two billion to three billion years ago spangled the Milky Way with a new generation of stars.

To understand how the Galaxy formed and evolved, astronomers need to know the rate at which its stars are born and how that rate has changed over time. But there is no way to measure the age of individual stars directly.

Roger Mor at the University of Barcelona in Spain and his colleagues turned to data from the Gaia satellite, which precisely measures the distance from Earth to millions of stars. These measurements allow researchers to calculate a star’s true brightness and size, which can be fed into models to infer its age.

The team simulated star formation in the Milky Way over time, and found it was in steady decline until roughly five billion years ago, when production suddenly ramped up. The researchers estimate that half the total mass of all the stars ever created in the Milky Way’s thin disk — which contains most of the Galaxy’s stars — was produced during this period.

Coloured scanning electron micrograph of Vibrio cholerae bacteria

Cholera-causing bacteria (above) succumb to a toxin after swallowing an apparently harmless circlet of DNA. Credit: Dennis Kunkel Microscopy/SPL

Biotechnology

Genetic ‘weapon’ picks off pathogens — but spares beneficial microbes

Structures made of DNA are designed to target the bacteria that cause cholera.

A bioengineered molecular ‘grenade’ unleashes a poison when ingested by specific bacteria, offering scientists a potential method for killing pathogens without harming beneficial microbes.

Bacterial cells often contain plasmids, ring-shaped structures made of DNA. Didier Mazel at the Pasteur Institute in Paris and his colleagues created plasmids that carry the genetic blueprint for an anti-bacterial toxin. The plasmids also carry genes that serve as switches. These switches allow toxin to be produced only after the plasmids are nestled inside antibiotic-resistant Vibrio cholerae, the bacterium that causes cholera. The researchers then loaded these plasmid ‘weapons’ into donor bacteria, which transferred them to V. cholerae cells.

The plasmids killed 100% of antibiotic-resistant cholera bacteria in a lab sample. They also killed cholera bacteria that had infected brine shrimp (Artemia nauplii) and zebrafish (Danio rerio) — but left the harmless bacteria in the animals’ microbiomes unscathed.

The plasmids’ genetic switches can be customized to direct the poisonous grenades to detonate inside a wide range of pathogens, the authors write.

A blue stick insect Achrioptera manga

The electric-blue males of the stick insect Achrioptera manga were previously ascribed to another species. Credit: F. Glaw <i>et al./Front. Ecol. Evol.</i>

Zoology

One of Earth’s biggest insects was hiding in plain sight

DNA analysis helps to resolve two cases of mistaken identity among Madagascan stick insects.

Most stick insects look like nondescript twigs, but two newly identified species could have come straight out of a psychedelic painting.

Sven Bradler at the University of Göttingen in Germany and his colleagues re-examined stick insects from Madagascar that had previously been classified as unusual examples of two known species. After analysing the insects’ DNA, the researchers found that the sky-blue males among the specimens belong to a new species, which they name Achrioptera manga. The DNA analysis also helped the team to identify another species of colourful, spiny stick insect from the island, Achrioptera maroloko. Females of this species reach up to 24 centimetres in length — meaning they rank among the world’s biggest known insects.

Why the insects have adopted bright colours is unclear: scientists suspect the flashy attire may be intended to attract mates or act as a deterrent to predators. Many species of poisonous frog use bright colours to scare away predators, and some stick insects might use a similar strategy, the researchers say.

Colorised mosaic of images from NASA's Cassini mission showing Titan's northern region of lakes and seas.

Near its north pole, Saturn’s moon Titan boasts deep, methane-rich lakes (blue, above) as well as ephemeral ponds that are less than ankle-deep. Credit: NASA/JPL-Caltech/ASI/USGS

Planetary science

Shallow lakes on a moon of Saturn mysteriously vanish from view

Titan’s land of lakes includes bodies that were seen in winter but had disappeared by the onset of spring.

The far northern reaches of Titan, Saturn’s largest moon, might feature seasonal lakes that vanish between winter and spring.

Studying images taken by NASA’s Cassini spacecraft in 2006, Shannon MacKenzie at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, and her colleagues spotted three dark patches during Titan’s winter, indicating the presence of lakes. When the spacecraft photographed the area again in 2013, after Titan’s spring equinox, the land was lighter in colour — suggesting that the lakes had dried up in the interim. These ‘phantom lakes’ might have been shallow ponds that were just a few millimetres deep.

Another research team used Cassini’s radar to probe several different northern lakes in April 2017, which turned out to be rich in liquid methane and more than 100 metres deep. They might have formed as methane rains on the moon dissolved rocks at its surface, says a team led by Marco Mastrogiuseppe at the California Institute of Technology in Pasadena.

Together, the studies show how Titan’s lakes evolve over time. If some of Titan’s lakes evaporate seasonally, they will be a less intriguing place to look for extraterrestrial life than in permanent bodies of liquid.

A bird’s eye view of an entangled photon-pair source built by researchers at the National University of Singapore and Singtel

A laser (grey and black box, bottom left) emits light that is converted into pairs of entangled photons suitable for generating a quantum key. Credit: National University of Singapore

Quantum physics

How to ensure a quantum key arrives on time

Adjustment to photons’ wavelengths could make their transmission through conventional fibre-optic cables more reliable.

Quantum encryption could become more efficient thanks to a method for better coordinating the photons at the heart of the process.

Streams of ‘entangled’ photons — pairs of intrinsically linked light particles — can generate tamper-proof cryptographic keys. To produce these keys, each of the photons in an entangled pair is sent through a fibre-optic cable to a separate operator. Each photon’s arrival is synchronized with its partner’s, allowing operators to match up the two members of a pair. But errors can occur because the photons’ arrival times become distorted by the particles spreading out as they travel through the cable.

James Grieve and his colleagues at the National University of Singapore managed to cancel out this effect by using photons at particular wavelengths: those that sit either side of an ideal wavelength at which no spreading occurs. This fix kept the entangled pairs in sync.

The team found that the technique improved photons’ arrival timing even when the particles travelled through a 10-kilometre-long commercial network made up of fibres with varying characteristics. The technique could be used to improve cryptography across distances on the scale of cities, and to synchronize clocks in financial trading, say the authors.

A group of World War One soldiers in front of the Sphinx and Pyramids of Egypt

Soldiers in Egypt during the First World War. A strain of cholera bacterium isolated from a soldier hospitalized in Egypt during the war was found to lack classic cholera toxin. Credit: Bettman/Getty

Microbiology

A 102-year-old bacterial culture reveals a microbe’s foul methods

A strain of cholera bacterium collected during the First World War is sequenced after decades in storage.

In 1916, against the backdrop of the First World War, a British soldier in an Egyptian hospital recovered from a bout of diarrhoea. More than a century later, scientists have revived a freeze-dried culture of a microbe that infected him — thought to be the oldest publicly available cholera bacterium in existence.

Nicholas Thomson at the Wellcome Sanger Institute in Hinxton, UK, and his colleagues sequenced the genome of NCTC 30, the strain of Vibrio cholerae that was isolated from the soldier and is now stored in a British microbial collection. NCTC 30 lacks the classic toxin needed to cause choleric diarrhoea, but the team found that the microbe’s genes contain instructions for a needle-like structure that projects from the bacterium’s surface. This appendage, which other bacteria use to inject proteins directly into host cells, might have caused the soldier’s symptoms. The researchers also identified genes that would have rendered the bacterium resistant to antibiotics — although penicillin wasn’t discovered until 1928.

Because so few V. cholerae isolates are available from this time period, comparisons between NCTC 30 and pandemic strains could provide valuable insights into their evolution, the authors say.

Judges taste beer during a competition at a beer festival

Judges’ palates hold sway at a beer competition, but an enhanced version of a common spectroscopic technique can pick out individual constituents of a brew. Credit: Kirsty Wigglesworth/AP/Shutterstock

Chemistry

A rich British stout is dissected with a virtual ‘scalpel’

Variation on nuclear magnetic resonance allows chemists to assess complex mixtures without destroying them.

A fresh approach to a standard analytical technique can detail a complicated mixture’s components without destroying the sample, allowing researchers to perform a ‘virtual dissection’ of a glass of beer.

Understanding the chemical contribution of each component in a complex system, such as a living cell, often means physically separating those components. That destroys the system and changes its chemistry. A technique called nuclear magnetic resonance spectroscopy (NMR) can identify an individual chemical by its unique radio-frequency signal, which shows up as a peak on a graph. But in complex mixtures, these signals overlap so much that disentangling them is almost impossible.

Instead of opting for the usual workaround — dissecting the sample — Mathias Nilsson at the University of Manchester, UK, and his colleagues divided the NMR measurements into small regions of the radio-frequency spectrum and examined one region at a time using statistical techniques. The approach, which the scientists dub SCALPEL, makes the individual signals stand out more clearly.

With this refinement, the team easily identified the maltose, lactose, glucose and ethanol in a glass of good British stout.

Paracatenula marine flatworm

Bacteria growing inside this Paracatenula flatworm provide their host with care packages of fats, sugars and other nutrients. Credit: Oliver Jäckle/Max Planck Institute for Marine Microbiology

Ecology

Gutless worms rely on handouts from internal microbes

Paracatenula worms store their energy in a peculiar ‘battery’: bacteria that dwell in the worms themselves.

If the worm Paracatenula had a mouth, one could say that the critter was born with a spoon in it. Despite lacking a gut, these sea-dwelling animals are always well fed, thanks to bacteria living inside the worms’ bodies that supply them with all the nutrients they need — in handy packages.

Paracatenula worms and a type of bacteria known as Candidatus Riegeria have been in a close relationship for at least 500 million years. Harald Gruber-Vodicka at the Max Planck Institute for Marine Microbiology in Bremen, Germany, and his colleagues studied a species of Paracatenula that lives off the coast of the Italian island of Elba. They found that over the past half a billion years, the worm’s bacterial partner has drastically reduced its genome size, keeping only the DNA needed for essential functions. Still, the microbe is able to provide the worm with all kinds of nutrients, including fats, sugars and amino acids.

In most similar partnerships, the host organism digests the bacteria to access the food that the microbe has made. But Paracatenula feeds on small, nutrient-packed droplets secreted by its partner bacteria.

A Volocopter 2X multirotor electric helicopter stands in a hangar at the Volocopter GmbH headquarters in Bruchsal, Germany

Electric vehicles such as this air taxi, built by the German manufacturer Volocopter, could aid efforts to make transport more sustainable. Credit: Michaela Rehle/Bloomberg/Getty

Technology

A jaunt by airborne ‘car’ can save on greenhouse gases

Over longer distances, a single-passenger flying car produces fewer emissions than does a petrol-powered vehicle on the roads.

Battery-powered ‘flying cars’ generate lower levels of greenhouse gases than do ground-based vehicles in some circumstances.

Flying cars now under development take off and land vertically, like helicopters, to make their airborne trips. Gregory Keoleian at the University of Michigan in Ann Arbor and his colleagues modelled the greenhouse-gas emissions attributable to battery-powered flying cars and ground-based vehicles powered by either electricity or petrol.

Flying cars performed better than petrol vehicles on single-occupant trips longer than 35 kilometres. For a single person travelling 100 kilometres, a flying car’s emissions were 28% higher than an electric vehicle’s but 35% lower than a petrol vehicle’s. Flying cars that were operated as a taxi service — assumed to include one pilot and three passengers — could even outperform electric vehicles on the ground, assuming the average US occupancy rate of 1.54 passengers per vehicle.

The authors suggest that shared flying cars could have a beneficial, if niche, role in the transportation system of the future.

A man walks through knee-high flood waters in a Texas neighbourhood affected by Hurricane Harvey

The catastrophic rains unleashed by Hurricane Harvey on Texas (pictured) in 2017 have been linked to climate change, which will raise the likelihood of similar events occurring across much of the United States. Credit: Spencer Platt/Getty

Climate change

Risk of ‘thousand-year’ rains could double for US states

Climate warming is raising the risk of rainfall intense enough to strain dams and other infrastructure.

Rare spells of extreme rainfall that would overwhelm today’s flood-defence infrastructure look set to become markedly more frequent in the United States as the climate changes.

Because a warmer atmosphere holds more moisture, episodes of extreme rainfall will increase overall as the world warms. To provide meaningful information about future flood risks, Benjamin Sanderson at the European Centre for Research and Advanced Training in Scientific Computing in Toulouse, France, and his colleagues divided the contiguous United States into 15 regions on the basis of precipitation patterns. For each region, the researchers modelled the probability of record-breaking three-day rainfall events for various climate scenarios.

The simulations suggest that 1000-year rainfalls — extreme events with a 1-in-1000 chance of happening in any given year — will become 2–5 times more frequent if the global temperature reaches 2°C above pre-industrial levels. With 4°C of warming, the models predict that such deluges will be up to 10 times more frequent.

New England, the Southern Great Plains and parts of the Rocky Mountains are among the US regions most at risk, the team found.

Correction: an earlier version of this article gave the wrong journal name for the reference.

Greater bilby at a burrow

Burrowing marsupials known as bilbies tunnel deep into the ground to escape the Australian desert’s searing heat. Credit: Roland Seitre/NPL

Zoology

‘Australia’s Easter bunnies’ provide shelter to wildlife in need

The burrows made by the rabbit-eared bilby serve as ‘outback oases’ for birds, reptiles and more.

The long-tailed Australian marsupials called bilbies are master engineers, capable of excavating multiple deep burrows within hours. Now cameras have caught a wide array of birds, reptiles and mammals taking advantage of the bilby’s earth-moving skills.

Stuart Dawson at Murdoch University in Australia and his colleagues mounted cameras near the burrows of greater bilbies (Macrotis lagotis), whose long ears have earned them the nickname ‘Australia’s Easter bunnies’. The team catalogued at least 45 species that spent time either in the burrow or at its entrance. After a wildfire, animals such as the dwarf bearded dragon (Pogona minor) were observed at burrows more often than before the fire.

The authors say that bilby burrows and their entrances can be an important source of shelter in arid regions, especially after wildfires, which rob small animals of a safe refuge by destroying plant cover. The ongoing decline in the bilby population is therefore threatening a broad range of species with the loss of essential sanctuary.

A construction worker drinks from a bottle of water at the site of a new road tunnel

Neural activity in a host of brain areas is involved in translating information about water availability into water-seeking behaviour, work in mice reveals. Credit: Khaled Desouki/AFP/Getty

Neuroscience

Thirst — and the prospect of a drink — fires up the brain

Activity radiates through a multitude of brain regions in parched mice presented with cues for water availability.

When thirsty mice receive cues that water is available, electrical patterns are unleashed throughout their brains, leading the animals to seek and consume water.

Liqun Luo and Karl Deisseroth at Stanford University in California and their colleagues recorded neural activity in mice as they drank water. On each run of the experiment, the team exposed mice to one of two odours: one indicated that licking a spout would produce water; the other indicated that licking the spout would yield nothing.

In thirsty animals, the odour that signalled water availability triggered a wave of neural activity that spread through all 34 brain regions that the team monitored. This activity persisted until just after the animals drank. In animals that were not thirsty, however, an initial wave occurred but tapered off quickly, and the animals did not try to drink.

The researchers then took sated mice and artificially activated neurons known to sense thirst. This restored brain-wide activity to the ‘thirsty state’ and induced water-seeking behaviour in these animals.

The results help to explain how neural signals for thirst control the transformation of sensory cues about water availability into goal-directed behaviours such as drinking.

Remains of a sacrificial guinea pig adorned with long colourful strings

This guinea pig was adorned by the Inca before its sacrifice roughly 400 years ago. Credit: L. Valdez/Int. J. Osteoarchaeol.

Archaeology

The Inca bedecked their sacrificial guinea pigs with earrings

Finding confirms historic reports that the rodents were killed en masse at South American ceremonies.

Buildings at the Inca site of Tambo Viejo, on the south coast of what is now Peru, were constructed with a very special kind of sub-flooring — sacrificed guinea pigs.

The Inca empire was one of many around the world that carried out animal sacrifice to its gods. Excavations by Lidio Valdez at the Institute of Andean Studies in Berkeley, California, show that dozens of guinea pigs (Cavia porcellus) were ritually sacrificed there around 400 years ago. The victims were adorned with necklaces and earrings made of orange, red, purple and brown strings. Some were wrapped in cotton rugs. The animals were covered with a layer of clean river sand — and might have been alive when buried. Clay floors were then built over the sand.

The site is so dry that the little mammals were neatly mummified, the colors of their string adornment still bright today.

The findings help to confirm early Spanish accounts of the sacrifice of large numbers of guinea pigs by the Inca.

The ESO Very Large Telescope at twilight, made up of four Unit Telescopes and four Auxiliary Telescopes

The Very Large Telescope in Antofagasta, Chile, includes four 8.2-metre telescopes (housed in tall structures). Credit: ESO/S. Brunier

Astronomy and astrophysics

An exoplanet’s stormy winds are revealed by telescope teamwork

A technique combines light from several telescopes to probe an exoplanet’s atmosphere.

A powerful technique has been used for the first time to assess a planet outside the Solar System.

Direct measurements of exoplanets are difficult, because the relatively dim light from planets blends into the glare of their host star. To solve this problem, astronomers seek approaches to separate a planet’s feeble light from its star’s brilliance.

A team led by Sylvestre Lacour and Mathias Nowak at the Paris Observatory harnessed the GRAVITY instrument at the Very Large Telescope (VLT) in Antofagasta, Chile, to directly observe exoplanets. Each of the VLT’s four 8.2-metre telescopes feeds its light to GRAVITY, which precisely aligns the input. This allows the light to be combined using a technique called optical interferometry.

The protocol created the equivalent of a single telescope that has as much light-collecting power as all four VLT telescopes put together — and a resolution an order of magnitude greater than any one of the four.

Artist’s impression of exoplanet HR8799e

An exoplanet (artist’s illustration) orbiting the star HR 8799 is several times more massive than Jupiter, according to new data from the Very Large Telescope.Credit: ESO/L. Calçada

The team measured the spectrum of a hot, young, ‘super-Jupiter’ orbiting the star HR 8799, which is roughly 40 parsecs from Earth. The results suggest that churning winds are disrupting the chemistry of the planet’s atmosphere.