New Solar System objects revealed - BBC News

Astronomers in the US have uncovered previously unknown objects in the outer reaches of the Solar System.

They include an icy body with an orbit that takes it so far from the Sun that it is probably influenced by the gravity of other stars.

The discoveries were found during an effort to locate a possible ninth planet, whose presence has been inferred indirectly.

The study is set to be published by The Astronomical Journal.

Co-authors Scott Sheppard and Chad Trujillo have submitted the details of their discoveries to the Minor Planet Center, which catalogues such objects, along with asteroids and comets.

Their search was carried out using several observatories around the world, including the the four-metre Blanco telescope in Chile and the eight-metre Subaru telescope in Hawaii.

One of the new objects, known for now as 2014 FE72, is the first distant Oort Cloud object found with an orbit entirely beyond Neptune.

Its orbit takes it some 3,000 times further than the Earth is from the Sun.

The Oort Cloud is the large shell of objects that occupies the outermost region of the Solar System.

Dr Sheppard, from the Carnegie Institution for Science in Washington and Dr Trujillo, from Northern Arizona University, have been analysing how the new planet-like bodies fit into larger theories about a ninth planet lurking in the Solar System's furthest reaches.

The evidence for this planet has largely been deduced by peculiarities of distant Solar System objects.

One of the new celestial bodies, 2013 FT28, shares characteristics of its orbit in common with the bodies whose positions and movements lent support to the planet nine idea - but it also shows some differences.

Based on analysis of other small bodies in the outer Solar System, astronomers have proposed that - if it exists - the ninth planet is several times more massive than Earth and is at least 200 times further than the distance between the Sun and Earth.

The new work should help constrain the location of this proposed ninth planet.

"The smaller objects can lead us to the much bigger planet we think exists out there," said Dr Sheppard.

"The more we discover, the better we will be able to understand what is going on in the outer Solar System."

Pluto, discovered in 1930, was previously known as the ninth planet. But its planetary status was removed in 2006, following the discovery of an object of comparable size in the Kuiper Belt, a ring of icy bodies just beyond Neptune.

Hear me now? 'Strong signal' from sun-like star sparks alien speculation

Astronomers engaged in the search for extraterrestrial intelligence (SETI) are training their instruments on a star around 94 light years from Earth after a very strong signal was detected by a Russian telescope.

An international team of researchers is now examining the radio signal and its star, HD 164595 -- described in a paper by Italian astronomer Claudio Maccone and others as a "strong candidate for SETI" -- in the hopes of determining its origin.

"The signal from HD 164595 is intriguing, because it comes from the vicinity of a sun-like star, and if it's artificial, its strength is great enough that it was clearly made by a civilization with capabilities beyond those of humankind," astronomer Douglas Vakoch, president of METI International, which searches for life beyond Earth, tells CNN.

Whenever a strong signal is detected, "it's a good possibility for some nearby civilization to be detected," Maccone tells CNN.

But experts say it is highly unlikely to be a message from alien beings.

"Without corroboration from an independent observatory, a putative signal from extraterrestrials doesn't have a lot of credibility," Vakoch says.

Advanced civilization?

Paul Gilster of the Tau Zero Foundation, which conducts interstellar research, said that if the signal was artificial, its strength suggested it would have to come from a civilization more advanced than our own.

Such a civilization would likely be Type II on the Kardashev scale, an attempt by the Soviet astronomer of the same name to categorize various technological stages of civilizations.

"The Kardashev scale is based basically on the energy that that civilization might be able to funnel for its own use," says Maccone.

At present, our own species is somewhere near Type I on the scale, whereby a civilization is able to harness all the energy available to it on its own planet, including solar, wind, earthquakes, and other fuels.

A Type II civilization would be able to harness the entirety of the energy emitted by its star, billions of billions of watts.

Doing so would require a colossal undertaking, likely the construction of some kind of superstructure, such as a giant sphere or swarm of super-advanced solar panels popularized by astronomer Freeman Dyson that could catch and store all radiation put out by the sun.

Scientists believe superstructures are probably our best chance of detecting alien life unless they are actively trying to communicate with us.

A Dyson sphere was one of the solutions suggested to the peculiar light fluctuations detected around Tabby's Star, which caused great excitement when they were detected last year.

Maccone is working on developing an alternative mathematical measure of how advanced civilizations are, based on the amount of knowledge and information available to them, that "might help us in the future classify alien civilizations" that we detect.

Dogs understand both words and intonation of human speech

Study finds that dogs process speech in a similar way to humans, and that what you say and how you say it both matter when conversing with canines

It is both what you say and the way that you say it that matters when it comes to communicating with man’s best friend, research has revealed.

Scientists from Hungary scanned the brains of dogs while each was played the sound of their trainer’s voice, and discovered that our canine companions only experience a sense of reward when both the words and intonation indicate praise.

The team also found that dogs process speech in a similar way to humans, processing meaningful words with their left hemisphere and intonation with a region in their right hemisphere.

Study raises possibility that two populations of grey wolves, separated by thousands of miles and years, may have resulted in modern domestic dogs

“The results were very exciting and very surprising,” said lead researcher Attila Andics from Eötvös Loránd University in Budapest.

Writing in the journal Science, Andics and colleagues describe how they trained 13 dogs over a period of months to lie motionless inside an fMRI machine, in order to probe how they process human speech.

The researchers used the scans to look at how their brain activity changed as they were played recordings of their trainers’ voices through a pair of headphones. Four different recordings were played with either praise words (such as “well done!”) or neutral words (such as “however” or “nevertheless”) coupled with either a high-pitched intonation indicative of praise, or a neutral intonation.

The results revealed that compared to neutral words, praise words resulted in an increase in activity in the left hemisphere of the brain for both types of intonation, suggesting that, like humans, dogs use the left side of their brain to process words that they have recognised and attach meaning to. On the other hand, differences in intonation but not word type, resulted in a change in activity in an area within the auditory region of the right hemisphere.

“It is actually the very same part of the brain in this right auditory brain region that we found in dogs and also humans in an earlier study that responds to the emotional content of a sound,” said Andics. “It is not a mechanism that is only there for language stimuli, it is the same mechanism dogs use for processing emotional sounds in general.”

26-year study of canine sperm shows an overall decline in quality, and may also shed light on fertility changes seen in male humans

The researchers also looked at the reward centre in the doggy brain, an area that responds to activities or experiences deemed pleasurable.

The results reveal that the reward centre only shows an increase in activity when both praise words and praise intonation are used.

“From this research, we can quite confidently say if they only hear you then it is not only how you say things but also what you say that matters to them,” said Andics.

But, says Andics, whether a dog can really tell if you are calling it a smelly hound in a jolly voice is another matter, as there are typically other cues, such as body language and facial expression at play.

The research, says Andics, offers new insights into the evolution of language.

“The neural mechanism humans have for processing meaning in speech, so for processing word meaning and intonation, are not uniquely human - they seem to be there in other species,” said Andics. That, he adds, suggests that our use of words was down to a novel idea, rather than new brain mechanisms. “It is not the result of a special new neural mechanism but the result of an innovation,” said Andics. “We invented words as we invented the wheel.”

The Anthropocene epoch: scientists declare dawn of human-influenced age

Experts say human impact on Earth so profound that Holocene must give way to epoch defined by nuclear tests, plastic pollution and domesticated chicken

Humanity’s impact on the Earth is now so profound that a new geological epoch – the Anthropocene – needs to be declared, according to an official expert group who presented the recommendation to the International Geological Congress in Cape Town on Monday.

The new epoch should begin about 1950, the experts said, and was likely to be defined by the radioactive elements dispersed across the planet by nuclear bomb tests, although an array of other signals, including plastic pollution, soot from power stations, concrete, and even the bones left by the global proliferation of the domestic chicken were now under consideration.

The current epoch, the Holocene, is the 12,000 years of stable climate since the last ice age during which all human civilisation developed. But the striking acceleration since the mid-20th century of carbon dioxide emissions and sea level rise, the global mass extinction of species, and the transformation of land by deforestation and development mark the end of that slice of geological time, the experts argue. The Earth is so profoundly changed that the Holocene must give way to the Anthropocene.

“The significance of the Anthropocene is that it sets a different trajectory for the Earth system, of which we of course are part,” said Prof Jan Zalasiewicz, a geologist at the University of Leicester and chair of the Working Group on the Anthropocene (WGA), which started work in 2009.

“If our recommendation is accepted, the Anthropocene will have started just a little before I was born,” he said. “We have lived most of our lives in something called the Anthropocene and are just realising the scale and permanence of the change.”

Prof Colin Waters, principal geologist at the British Geological Survey and WGA secretary, said: “Being able to pinpoint an interval of time is saying something about how we have had an incredible impact on the environment of our planet. The concept of the Anthropocene manages to pull all these ideas of environmental change together.”

Prof Chris Rapley, a climate scientist at University College London and former director of the Science Museum in London said: “The Anthropocene marks a new period in which our collective activities dominate the planetary machinery.

“Since the planet is our life support system – we are essentially the crew of a largish spaceship – interference with its functioning at this level and on this scale is highly significant. If you or I were crew on a smaller spacecraft, it would be unthinkable to interfere with the systems that provide us with air, water, fodder and climate control. But the shift into the Anthropocene tells us that we are playing with fire, a potentially reckless mode of behaviour which we are likely to come to regret unless we get a grip on the situation.” Rapley is not part of the WGA.

Martin Rees, the astronomer royal and former president of the Royal Society, said that the dawn of the Anthropocene was a significant moment. “The darkest prognosis for the next millennium is that bio, cyber or environmental catastrophes could foreclose humanity’s immense potential, leaving a depleted biosphere,” he said.

But Lord Rees added that there is also cause for optimism. “Human societies could navigate these threats, achieve a sustainable future, and inaugurate eras of post-human evolution even more marvellous than what’s led to us. The dawn of the Anthropocene epoch would then mark a one-off transformation from a natural world to one where humans jumpstart the transition to electronic (and potentially immortal) entities, that transcend our limitations and eventually spread their influence far beyond the Earth.”

The evidence of humanity’s impact on the planet is overwhelming, but the changes are very recent in geological terms, where an epoch usually spans tens of millions of years. “One criticism of the Anthropocene as geology is that it is very short,” said Zalasiewicz. “Our response is that many of the changes are irreversible.”

To define a new geological epoch, a signal must be found that occurs globally and will be incorporated into deposits in the future geological record. For example, the extinction of the dinosaurs 66m years ago at the end of the Cretaceous epoch is defined by a “golden spike” in sediments around the world of the metal iridium, which was dispersed from the meteorite that collided with Earth to end the dinosaur age.

For the Anthropocene, the best candidate for such a golden spike are radioactive elements from nuclear bomb tests, which were blown into the stratosphere before settling down to Earth. “The radionuclides are probably the sharpest – they really come on with a bang,” said Zalasiewicz. “But we are spoiled for choice. There are so many signals.”

Other spikes being considered as evidence of the onset of the Anthropocene include the tough, unburned carbon spheres emitted by power stations. “The Earth has been smoked, with signals very clearly around the world in the mid-20th century,” said Zalasiewicz.

Other candidates include plastic pollution, aluminium and concrete particles, and high levels of nitrogen and phosphate in soils, derived from artificial fertilisers. Although the world is currently seeing only the sixth mass extinction of species in the 700m-year history of complex life on Earth, this is unlikely to provide a useful golden spike as the animals are by definition very rare and rarely dispersed worldwide.

In contrast, some species have with human help spread rapidly across the world. The domestic chicken is a serious contender to be a fossil that defines the Anthropocene for future geologists. “Since the mid-20th century, it has become the world’s most common bird. It has been fossilised in thousands of landfill sites and on street corners around the world,” said Zalasiewicz. “It is is also a much bigger bird with a different skeleton than its prewar ancestor.”

The 35 scientists on the WGA – who voted 30 to three in favour of formally designating the Anthropocene, with two abstentions – will now spend the next two to three years determining which signals are the strongest and sharpest. Crucially, they must also decide a location which will define the start of the Anthropocene. Geological divisions are not defined by dates but by a specific boundary between layers of rock or, in the case of the Holocene, a boundary between two ice layers in a core taken from Greenland and now stored in Denmark.

The scientists are focusing on sites where annual layers are formed and are investigating mud sediments off the coast of Santa Barbara in California and the Ernesto cave in northern Italy, where stalactites and stalagmites accrete annual rings. Lake sediments, ice cores from Antarctica, corals, tree rings and even layers of rubbish in landfill sites are also being considered.

Once the data has been assembled, it will be formally submitted to the stratigraphic authorities and the Anthropocene could be officially adopted within a few years. “If we were very lucky and someone came forward with, say, a core from a classic example of laminated sediments in a deep marine environment, I think three years is possibly viable,” said Zalasiewicz.

This would be lightning speed for such a geological decision, which in the past would have taken decades and even centuries to make. The term Anthropocene was coined only in 2000, by the Nobel prize-winning scientist Paul Crutzen, who believes the name change is overdue. He said in 2011: “This name change stresses the enormity of humanity’s responsibility as stewards of the Earth.” Crutzen also identified in 2007 what he called the “great acceleration” of human impacts on the planet from the mid-20th century.

Despite the WGA’s expert recommendation, the declaration of the Anthropocene is not yet a forgone conclusion. “Our stratigraphic colleagues are very protective of the geological time scale. They see it very rightly as the backbone of geology and they do not amend it lightly,” said Zalasiewicz. “But I think we can prepare a pretty good case.”

Rapley also said there was a strong case: “It is highly appropriate that geologists should pay formal attention to a change in the signal within sedimentary rock layers that will be clearly apparent to future generations of geologists for as long as they exist. The ‘great acceleration’ constitutes a strong, detectable and incontrovertible signal.”
Evidence of the Anthropocene

Human activity has:

    Pushed extinction rates of animals and plants far above the long-term average. The Earth is on course to see 75% of species become extinct in the next few centuries if current trends continue.

    Increased levels of climate-warming CO2 in the atmosphere at the fastest rate for 66m years, with fossil-fuel burning pushing levels from 280 parts per million before the industrial revolution to 400ppm and rising today.

    Put so much plastic in our waterways and oceans that microplastic particles are now virtually ubiquitous, and plastics will likely leave identifiable fossil records for future generations to discover.

    Doubled the nitrogen and phosphorous in our soils in the past century with fertiliser use. This is likely to be the largest impact on the nitrogen cycle in 2.5bn years.

    Left a permanent layer of airborne particulates in sediment and glacial ice such as black carbon from fossil fuel burning.

Mediterranean diet better for the heart than taking statins, major study suggests

A Mediterranean diet could be better than statins at reducing the risk of an early death for millions of Britons, research suggests.

Leading heart experts said patients should be prescribed the diet - rich in fruit, vegetables, fish, nuts, whole grains and olive oil - before being put on drugs.

In the first major study to look at the impact of the Med diet on survival of heart patients, experts found it cut the chances of early death by 37 per cent.

Previous research has found just taking statins cuts mortality by 18 per cent. Experts said the figures were not directly comparable, and that many heart patients could get maximum benefit by doing both.

But they said the results were so remarkable that the state should consider handing out free fruit and vegetables, or subsidising such produce, to encourage the public to change its eating habits. Seven million people in Britain live with heart disease.

The diet regime is already known to have a powerful protective effect against a number of diseases, including diabetes and cancer.

Experts hailed the new findings, presented at the world's biggest heart conference in Rome, Italy, as “extraordinary”, showing that the diet was “more powerful than any drug”.

High consumption of vegetables had the greatest impact on survival, followed by oily fish intake, amount of fruit eaten and consumption of mono-unsaturated fat, found in olive oil.

Professor Giovanni de Gaetano, head of the Department of Epidemiology and Prevention at the IRCCS Neuromed Institute in Italy, said: "We found that among those with a higher adherence to the Mediterranean diet, death from any cause was reduced by 37 per cent in comparison to those who poorly adhered to this dietary regime.

"The Mediterranean diet is widely recognised as one of the healthier nutrition habits in the world.

"In fact, many scientific studies have shown that a traditional Mediterranean lifestyle is associated with a lower risk of various chronic diseases and, more importantly, of death from any cause.

"But so far research has focused on the general population, which is mainly composed of healthy people. What happens to people who have already suffered from cardiovascular disease? Is the Mediterranean diet optimal for them too?”

He said the research suggested exactly this, with the Med diet showing a "powerful" effect, cutting deaths from all causes.

Doctors should "consider diet before drugs" and the state should subsidise fruit and vegetables to encourage Britons towards healthier diets, he said.

“The National Health Service pays for drugs, but it doesn’t pay for vegetables,” he said. “The state should consider contributing towards those foods that make up the Mediterranean diet.”

NASA's Juno probe gets its first close look at Jupiter

Soaring about 2,600 miles (4,200 kilometers) above the planet's clouds, NASA's Juno space probe had its closest-ever look at Jupiter Saturday.

The pass was the first of 36 planned orbital flybys, NASA said in a statement. Soaring at 130,000 miles per hour (208,000 kilometers per hour), it was the nearest the spacecraft will get to Jupiter during its main mission, which should end in February 2018.

Juno launched from Florida on Aug. 5, 2011, and in July, became the first probe to orbit Jupiter since NASA's Galileo mission ended in 2003.

The nerve wracking five year journey into space, and Juno successful attempt to enter into orbit around Jupiter, were hailed by scientists as an immense opportunity to discover more about the mysterious gas planet.

It's thought that new moons beyond the 67 we know about could be found. By mapping the planet's magnetic fields, scientists are also hoping to unearth new clues about how our solar system was formed.

About the size of a basketball court, the Juno probe had all its scientific instruments on and turned to Jupiter Saturday, attempting to gather as much data as possible. Images captured by JunoCam during the trip will be released shortly, including shots of Jupiter's north and south poles.

"We are in an orbit nobody has ever been in before, and these images give us a whole new perspective on this gas-giant world," Scott Bolton, Juno principal investigator, said in the statement.

"We are getting some intriguing early data returns as we speak," he added. "It will take days for all the science data collected during the flyby to be downlinked and even more to begin to comprehend what Juno and Jupiter are trying to tell us."

After its 20-month-mission ends, Juno will be plunged into Jupiter's clouds by NASA engineers. But for now, it has plenty of work left to do.

How DNA left at crime scenes could help 'recreate' faces of criminals after gene breakthrough

The faces of murderers and rapists could be "recreated" from DNA left at the scene of the crime, according to new research.

Scientists have identified genes that shape the extraordinary variation in the human face.

Many features, such as nose size and face width, stem from specific mutations, say researchers.

Previous studies have suggested they are controlled by genes, but this one is the first to shed light on how variants contribute to the range of different forms we see.

The findings, published in PLOS Genetics, may also help researchers to learn how facial birth defects arise.

And they could even have applications in forensics, helping police construct more accurate faces of dangerous criminals being hunted for murders, rapes and robberies.

The discovery of the genes that determine human face shapes could provide valuable information about a person's appearance using just DNA left behind at the scene of a crime.

The face shapes are based on a DNA analysis of 20 facial characteristics measured from 3D images of 3,118 healthy volunteers of European ancestry and almost a million mutations, or SNPs (single base pair) variations.

Dr John Shaffer, of the University of Pittsburgh, said: "There is a great deal of evidence genes influence facial appearance.

"This is perhaps most apparent when we look at our own families, since we are more likely to share facial features in common with our close relatives than with unrelated individuals.

"Nevertheless, little is known about how variation in specific regions of the genome relates to the kinds of distinguishing facial characteristics that give us our unique identities, e.g. the size and shape of our nose or how far apart our eyes are spaced.

"In this paper, we investigate this question by examining the association between genetic variants across the whole genome and a set of measurements designed to capture key aspects of facial form.

"We found evidence of genetic associations involving measures of eye, nose, and facial breadth.

"In several cases, implicated regions contained genes known to play roles in embryonic face formation or in syndromes in which the face is affected.

"Our ability to connect specific genetic variants to ubiquitous facial traits can inform our understanding of normal and abnormal craniofacial development, provide potential predictive models of evolutionary changes in human facial features, and improve our ability to create forensic facial reconstructions from DNA."

Facial width, the distance between the eyes, the size of the nose and the distance between the lips and eyes all had statistically significant associations with certain SNPs.

The researchers also considered results from two similar studies and confirmed certain previous findings.

Until recently, virtually nothing was known about the genes responsible for facial shape in humans.

Dr Seth Weinberg, co-author, added: "Our analysis identified several genetic associations with facial features not previously described in earlier genome wide studies.

"What is exciting is many of these associations involve chromosomal regions harbouring genes with known craniofacial function.

"Such findings can provide insights into the role genes play in the formation of the face and improve our understanding of the causal factors leading to certain craniofacial birth defects."

Several of the genetic regions contributing to face shape detected contain genes known to play a role in facial development and abnormalities.

In the future, the scientists hope to identify genetic risk factors that lead to anomalies such as cleft lip and palate.

But they warned it is important to keep in mind these findings likely represent only a small fraction of the genes influencing the size and shape of the human face.

Many of the genes influencing facial features are likely to have small effects, so successfully mapping a large number of these genes will require much greater sample sizes and a more comprehensive approach to quantifying those of interest.

There's an Earth-like planet in our galactic neighborhood — and it may have conditions for life

Pale blue dot, meet pale red dot.

Astronomers have spent decades scouring the skies looking for Earth-sized planets around distant stars. And now they’ve found one, sitting smack in the habitable zone of our nearest stellar neighbor.

Proxima b, described Wednesday in the journal Nature, could be one of the first planets where humans might find life outside our solar system.

“It’s the closest star. It has a potentially habitable world. I just think it’s amazing,” said Cornell astrophysicist Lisa Kaltenegger, who was not involved in the discovery. “This is just such a great, exciting time to live in because we’ll figure out how we fit into all of this — and hopefully, also, if we’re alone in the universe.”

The discovery comes four months after the announcement of Breakthrough Starshot, an initiative to build and send tiny spacecraft to the nearest star system within the coming decades. Now the project has a tantalizing planetary target.

“The technology today is sufficient to begin thinking about these things,” said Pete Worden, Breakthrough Starshot’s executive director and the former head of NASA’s Ames Research Center. “We are really excited, and, to use the U.S. term, pumped, about this discovery. We’re on our way.”

Proxima b orbits Proxima Centauri, the third wheel to the binary star pair known as Alpha Centauri AB. As its name suggests, Proxima Centauri is the closest star to our solar system, sitting a relatively close 4.2 light-years away. But as an M-dwarf — a dim, red, low-mass star — it can’t be seen from Earth with the naked eye. It has just 12% of the sun’s mass and 0.15% of its luminosity.

The newly discovered planet is estimated to hold at least 1.3 Earth masses, which means it’s probably a rocky world like our own. And though it lies a mere 4.3 million miles or so from the surface of its star — about nine times closer than Mercury is to the sun — Proxima Centauri is so dim that water, theoretically, could remain stable on the planet’s surface, assuming there’s a protective atmosphere.

Scientists discovered Proxima b thanks to what’s known as the radial velocity method, which takes advantage of the Doppler effect. As a planet moves around its star, it tugs just a little bit, causing the star to wobble back and forth. When the wobble brings the star closer to us, the light reaching us is squeezed, making it bluer. When the star is pulled slightly away from us, the light is stretched, making it redder. That color shift allows astronomers to determine the mass of the planet tugging on it.

In some ways, this is simpler to do with M dwarfs; because of their size, they’re more easily pulled this way and that by their planets. And since Proxima b completes an entire orbit in just 11.2 Earth days, the tugging should be easy to pick out. Plus, as the star closest to us, Proxima Centauri is one of the best-studied red dwarfs to date.

And yet it took years to find the planet. That’s partly because M dwarfs are very noisy, variable stars whose activity can drown out the Doppler signal. Observations made years earlier revealed hints of the planet but could not decisively prove its existence.

“The data collected for this research [span] 16 years,” said study coauthor Pedro Amado, an astrophysicist at the Institute of Astrophysics of Andalusia in Granada, Spain. “The first datasets did not show anything, but as our analysis technique improved and we added data from more precise instruments, a periodic signal started to show up.”

This year, a team of astronomers known as the Pale Red Dot campaign studied Proxima Centauri with the European Southern Observatory’s HARPS instrument, a spectrograph installed on the 3.8-meter telescope at La Silla in Chile. Using other telescopes, they monitored the star’s brightness to make sure that its own variability wasn’t producing the tantalizing exoplanetary signal.

They found that, at times, Proxima Centauri was moving toward or away from Earth at roughly 3 mph — a typical human walking pace. An unseen planet, they realized, must be tugging on this star.

“All the pieces together is what allows us to be very, very sure that we have it right this time,” said study leader Guillem Anglada-Escuse, a planet hunter at the Queen Mary University of London.

As it happens, there was another signal mixed into the data — one that might hint at the existence of a larger, more distant planet circling Proxima Centauri.

Could life exist on Proxima b? There are several unknowns that make it impossible to say right now, according to scientists. The planet is tidally locked to Proxima Centauri, so one side may permanently face the star while the other remains shrouded in darkness. But if there is an atmosphere, it should redistribute heat across the surface, the researchers said.

As an M dwarf, Proxima Centauri is prone to frequent flares and bursts of X-rays that would send down 400 times the X-ray flux that Earth receives from the sun, according to the study. Those X-rays could eat away at the atmosphere, even if one exists.

And it’s also not clear whether water could have survived on the planet over the eons. The answer depends on how violent the star was in the past and where the planet originated — both of which remain a mystery.

“This is the biggest question mark for the question of whether it’s an Earth-like planet or not,” said study coauthor Ansgar Reiners of the University of Goettingen in Germany. “This will be subject to further studies.”

Fortunately, Proxima Centauri and its planetary companion are so close that it should be relatively easy to start probing these questions. Some teams already have started.

If there were life on this planet, it probably survived either underground or deep within its hypothetical oceans, said Kaltenegger, the director of Cornell’s Carl Sagan Institute, which is dedicated to the search for habitable worlds. But there’s a chance that organisms evolved to handle the extreme radiation that may reach the surface, she added, perhaps by using biofluorescence.

The discovery signals a shift in the hunt for exoplanets, from broad surveys such as NASA’s Kepler and K2 missions toward in-depth profiles of individual planets, said MIT astrophysicist Sara Seager, who was not involved in the work.

“Exoplanets,” she said, are “the gift that keeps on giving.”
How scientists use satellite data to track poverty in Africa
Caption How scientists use satellite data to track poverty in Africa
Watch a time-lapse video of the Perseid meteor shower from Joshua Tree
Caption Watch a time-lapse video of the Perseid meteor shower from Joshua Tree

There’s only a 1.5% chance that Proxima b’s transiting across its star’s surface is visible from Earth, which means researchers will probably not be able to study its atmosphere for a while. But as ever more-powerful telescopes come online, it may be possible to take images of this nearby star system.

Plans to visit Proxima b remain an exceedingly distant prospect. With current technology, it would probably take tens of thousands of years to get there — and more than four years just to send a message back.

In April, physicist Stephen Hawking and Russian billionaire Yuri Milner announced the $100-million Breakthrough Starshot program that aims to build nanosatellites capable of accelerating to 20% of the speed of light. At that rate, it would take roughly 20 years to reach our nearest neighbors — and it could take much longer for that technology to be designed and built.

In the meantime, scientists will probably have their hands full studying Proxima b from Earth.

“Our picture of the galactic neighborhood has changed,” Reiners said. “We have a new neighbor, and there will likely be a whole branch of science aiming to understand its nature.”