Dec 30, 2015

Social, telepresence robots revealed by scientists

Prof Nadia Thalmann (left) posing beside Nadine, a life-like social robot capable of autonomously expressing emotions and gestures.
Say hello to Nadine, a "receptionist" at Nanyang Technological University (NTU Singapore). She is friendly, and will greet you back. Next time you meet her, she will remember your name and your previous conversation with her.

She looks almost like a human being, with soft skin and flowing brunette hair. She smiles when greeting you, looks at you in the eye when talking, and can also shake hands with you. And she is a humanoid.

Unlike conventional robots, Nadine has her own personality, mood and emotions. She can be happy or sad, depending on the conversation. She also has a good memory, and can recognise the people she has met, and remembers what the person had said before.

Nadine is the latest social robot developed by scientists at NTU. The doppelganger of its creator, Prof Nadia Thalmann, Nadine is powered by intelligent software similar to Apple's Siri or Microsoft's Cortana. Nadine can be a personal assistant in offices and homes in future. And she can be used as social companions for the young and the elderly.

A humanoid like Nadine is just one of the interfaces where the technology can be applied. It can also be made virtual and appear on a TV or computer screen, and become a low-cost virtual social companion.

With further progress in robotics sparked by technological improvements in silicon chips, sensors and computation, physical social robots such as Nadine are poised to become more visible in offices and homes in future.

The rise of social robots

Prof Thalmann, the director of the Institute for Media Innovation who led the development of Nadine, said these social robots are among NTU's many exciting new media innovations that companies can leverage for commercialisation.

"Robotics technologies have advanced significantly over the past few decades and are already being used in manufacturing and logistics. As countries worldwide face challenges of an aging population, social robots can be one solution to address the shrinking workforce, become personal companions for children and the elderly at home, and even serve as a platform for healthcare services in future," explained Prof Thalmann, an expert in virtual humans and a faculty from NTU's School of Computer Engineering.

"Over the past four years, our team at NTU have been fostering cross-disciplinary research in social robotics technologies -- involving engineering, computer science, linguistics, psychology and other fields -- to transform a virtual human, from within a computer, into a physical being that is able to observe and interact with other humans.

"This is somewhat like a real companion that is always with you and conscious of what is happening. So in future, these socially intelligent robots could be like C-3PO, the iconic golden droid from Star Wars, with knowledge of language and etiquette."

Telepresence robot lets people be in two or more places at once

Nadine's robot-in-arms, EDGAR, was also put through its paces at NTU's new media showcase, complete with a rear-projection screen for its face and two highly articulated arms.

EDGAR is a tele-presence robot optimised to project the gestures of its human user. By standing in front of a specialised webcam, a user can control EDGAR remotely from anywhere in the world. The user's face and expressions will be displayed on the robot's face in real time, while the robot mimics the person's upper body movements.

EDGAR can also deliver speeches by autonomously acting out a script. With an integrated webcam, he automatically tracks the people he meets to engage them in conversation, giving them informative and witty replies to their questions.

Such social robots are ideal for use at public venues, such as tourist attractions and shopping centres, as they can offer practical information to visitors.

Led by Assoc Prof Gerald Seet from the School of Mechanical & Aerospace Engineering and the BeingThere Centre at NTU, this made-in-Singapore robot represents three years of research and development.

Read more at Science Daily

Exceptionally strong and lightweight new metal

At left, a deformed sample of pure metal; at right, the strong new metal made of magnesium with silicon carbide nanoparticles. Each central micropillar is about 4 micrometers across.
A team led by researchers from the UCLA Henry Samueli School of Engineering and Applied Science has created a super-strong yet light structural metal with extremely high specific strength and modulus, or stiffness-to-weight ratio. The new metal is composed of magnesium infused with a dense and even dispersal of ceramic silicon carbide nanoparticles. It could be used to make lighter airplanes, spacecraft, and cars, helping to improve fuel efficiency, as well as in mobile electronics and biomedical devices.

To create the super-strong but lightweight metal, the team found a new way to disperse and stabilize nanoparticles in molten metals. They also developed a scalable manufacturing method that could pave the way for more high-performance lightweight metals. The research was published today in Nature.

"It's been proposed that nanoparticles could really enhance the strength of metals without damaging their plasticity, especially light metals like magnesium, but no groups have been able to disperse ceramic nanoparticles in molten metals until now," said Xiaochun Li, the principal investigator on the research and Raytheon Chair in Manufacturing Engineering at UCLA. "With an infusion of physics and materials processing, our method paves a new way to enhance the performance of many different kinds of metals by evenly infusing dense nanoparticles to enhance the performance of metals to meet energy and sustainability challenges in today's society."

Structural metals are load-bearing metals; they are used in buildings and vehicles. Magnesium, at just two-thirds the density of aluminum, is the lightest structural metal. Silicon carbide is an ultra-hard ceramic commonly used in industrial cutting blades. The researchers' technique of infusing a large number of silicon carbide particles smaller than 100 nanometers into magnesium added significant strength, stiffness, plasticity and durability under high temperatures.

The researchers' new silicon carbide-infused magnesium demonstrated record levels of specific strength -- how much weight a material can withstand before breaking -- and specific modulus -- the material's stiffness-to-weight ratio. It also showed superior stability at high temperatures.

Ceramic particles have long been considered as a potential way to make metals stronger. However, with microscale ceramic particles, the infusion process results in a loss of plasticity.

Nanoscale particles, by contrast, can enhance strength while maintaining or even improving metals' plasticity. But nanoscale ceramic particles tend to clump together rather than dispersing evenly, due to the tendency of small particles to attract one other.

To counteract this issue, researchers dispersed the particles into a molten magnesium zinc alloy. The newly discovered nanoparticle dispersion relies on the kinetic energy in the particles' movement. This stabilizes the particles' dispersion and prevents clumping.

To further enhance the new metal's strength, the researchers used a technique called high-pressure torsion to compress it.

"The results we obtained so far are just scratching the surface of the hidden treasure for a new class of metals with revolutionary properties and functionalities," Li said.

The new metal (more accurately called a metal nanocomposite) is about 14 percent silicon carbide nanoparticles and 86 percent magnesium. The researchers noted that magnesium is an abundant resource and that scaling up its use would not cause environmental damage.

The paper's lead author is Lian-Yi Chen, who conducted the research as a postdoctoral scholar in Li's Scifacturing Laboratory at UCLA. Chen is now an assistant professor of mechanical and aerospace engineering at Missouri University of Science and Technology.

Read more at Science Daily

ALMA Spies Baby Stars' Planetary Workshops

This artist's impression shows the formation of massive planets in the dust gap of a transitional disk surrounding a young star.
Planetary formation remains one of the biggest puzzles in modern astronomy. Although we know that the vast majority of stars possess systems of planets — from tiny Mercury-sized rocky worlds to massive gas giants that would dwarf Jupiter — mysteries remain as to how material accretes to form small planetoids and how long it takes for these planetary embryos to plump-up into what we would consider to be planets.

Now, with the help of the awesome Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have zoomed-in on a selection of very young stars, revealing never-before-seen detail in the planet-forming regions surrounding them. And what they found were monster planets, several times more massive than Jupiter, hiding inside the dusty planetary workshops.

When a star is born, it will often be accompanied by a protoplanetary disk. As the star settles and disk matures, small dusty particles accrete (clump together), eventually creating gravitationally-dominant protoplanets that rapidly vacuum up more and more material, growing bigger and more massive. Of particular interest to astronomers are transitional disks that have a surprising lack of dust in their centers, in the region between the disk and star.

This may not seem surprising; astronomers have explained away these features as either a consequence of stellar radiation pressure (as the star matures, its radiation blasts any nearby dust away), or massive planets could be lurking in this zone, having cleared their orbits of dust through their gravitational dominance.

We’ve been stuck at this impasse for some time; how can we tell whether this dust gap is caused by radiation pressure or planetary formation?

This ALMA image combines a view of the dust around the young star HD 135344B (orange) with a view of the gaseous material (blue). The smaller hole in the inner gas is a telltale sign of the presence of a young planet clearing the disc. The bar at the bottom of the image indicates the diameter of the orbit of Neptune in the Solar System (60 AU).
This is where ALMA comes in. The array of radio antennae are sensitive to emissions from the gas these transitional disks contain and through studies of 4 young stars, astronomers have found that inside these dust gaps, there are also gas gaps, but they are 3 times thinner. Only with ALMA’s precision observations could these gas gaps be pinpointed and they can mean only one thing.

“Previous observations already hinted at the presence of gas inside the dust gaps,” said astronomer Nienke van der Marel, of Leiden Observatory in the Netherlands. “But as ALMA can image the material in the entire disc in much greater detail than other facilities, we could rule out the alternative scenario. The deep gap points clearly to the presence of planets with several times the mass of Jupiter, creating these caverns as they sweep through the disc.”

Although we are looking at very alien star systems, it’s studies such as these that will ultimately reveal how the planets in our own solar system formed, likely clearing up many mysteries surrounding our understanding of planetary evolution. And as observatories become more sophisticated answers are likely to come sooner rather than later.

Read more at Discovery News

Prehistoric Giant Armadillo Shell Found in Argentina

A passer-by on Christmas Day found a meter-long shell on a riverbank in Argentina which may be from a glyptodont, a prehistoric kind of giant armadillo, experts said Tuesday.

A local man thought the black scaly shell was a dinosaur egg when he saw it lying in the mud, his wife Reina Coronel told AFP.

Her husband Jose Antonio Nievas found the shell beside a stream at their farm in Carlos Spegazzini, about 40 kilometers (25 miles) south of the capital Buenos Aires.

“My husband went out to the car and when he came back he said, ‘Hey, I just found an egg that looks like it came from a dinosaur,” she said.

“We all laughed because we thought it was a joke.”

Nievas told television channel Todo Noticias he found the shell partly covered in mud and started to dig around it.

Various experts who saw television pictures of the object said it was likely to be a glyptodont shell.

“There is no doubt that it looks like a glyptodont,” said paleontologist Alejandro Kramarz of the Bernadino Rivadavia Natural Sciences Museum.

“The animal became extinct thousands of years ago and it is very common to find their fossils in this region,” he told AFP.

Glyptodonts are the ancestors of modern armadillos. They had big round armored shells and weighed up to a ton.

They lived in South America for tens of millions of years.

Kramarz estimated the specimen found by Nievas was relatively young at 10,000 years.

From Discovery News

Dec 29, 2015

Second Form of Contagious Cancer Found in Tasmanian Devils

A newly observed form of cancer in Tasmanian devils can be spread by biting, researchers say.

With eight reported cases across southeastern Tasmania, the cancer causes large facial tumors in infected devils and can result in death within months.

This is the second transmissible cancer known to affect the species. The other form, which was first observed in 1996, is also spread via bites and results in facial tumors, but is genetically distinct.

Known as devil facial tumor disease, the parasitic cancer has been blamed for significant population declines in recent years, as devils are known to bite each other frequently during mating and feeding. In 2008, the IUCN categorized the Tasmanian devil (Sarcophilus harrisii) as Endangered, noting that some individual populations are now a mere tenth of their original size.

Some devils are immune to devil facial tumor disease, and captive breeding programs have been initiated as a last-ditch effort to ensure the species’ long-term survival.

“Until now, we’ve always thought that transmissible cancers arise extremely rarely in nature, but this new discovery makes us question this belief,” the University of Cambridge’s Dr. Elizabeth Murchison, senior author of a new study about the cancer, remarked in a news release.

“It makes us wonder if Tasmanian devils might be particularly vulnerable to developing this type of disease, or that transmissible cancers may not be as rare in nature as we previously thought.”

Similar transmissible cancers have also been observed in dogs and soft-shell clams.

The research, from the Universities of Cambridge and Tasmania, is detailed the journal Proceedings of the National Academy of Science.

From Discovery News

U.K. Zoo Attempts to Save World's Rarest Magpie

The Javan green magpie is in trouble, critically endangered, with precious few of its kind remaining, and the U.K.’s Chester Zoo is making an effort to save it from extinction.

The zoo has taken receipt of six pairs of the stunning green birds from their native Indonesia and hopes to establish a breeding program and what it calls "safety-net" populations.

According to the zoo, there are only about 100 Javan green magpies left. Birds in Indonesia are often caged as status objects, causing millions of them to be removed from the wild over the last two decades or so. In such conditions birds like the green magpie don’t survive very long, say zoo staff interviewed by the BBC.

Recent efforts by the zoo to work with conservationists in Indonesia to breed the birds have been hindered by break-ins by thieves targeting the rare creatures.

The break-ins prompted the zoo to have the six pairs of birds flown to the United Kingdom. The U.K. breeding program will be the first ever attempted outside of the magpie’s native Indonesia.

The Javan green magpie is a corvid, in the same family as crows and ravens. Its victimization by trappers, and its loss of native habitat in the forests of Indonesia give the bird its ominous Critically Endangered designation.

“Research and informed conservation actions are now urgently needed to increase the chances of this species’s survival,” the International Union for Conservation of Nature writes of the animal on its “red list” of threatened species.

From Discovery News

Ancient Ram Statue Unearthed On Christmas Eve in Israel

Israeli archaeologists on Christmas Eve unearthed an impressive marble statue of a ram they believe may have been meant to represent the faithful, or Jesus himself.

Found in the ancient port city of Caesarea near a Byzantine church, the well-preserved statue represents a rather common image in Christian art.

“In ancient Christianity Jesus was not portrayed as a person. Instead, symbols were used, one of which was the ram,” Peter Gendelman and Mohammad Hater, directors of the excavation on behalf of the Israel Antiquities Authority, said in a statement.

According to the archaeologists, the statue might have been part of the decoration of a Byzantine church from the sixth to seventh centuries AD.

“By the same token it could also be earlier, from the Roman period, and was incorporated in secondary use in the church structure,” Gendelman and Hater said.

Appearing alongside the Greek gods Hermes and Mercury, the ram was often used in Roman art. It was also portrayed in Egyptian mythology as a representation of the god Amun.

In Christian imagery, the animal is often depicted carried on the shoulders of the “Good Shepherd,” that is, Jesus, and sometimes the animal is situated to the left or right of Jesus.

“It may or may not be a coincidence, but the statue was uncovered on Christmas Eve,” Gendelman and Hater said.

From Discovery News

Huge Storm May Raise North Pole Temps 50 Degrees

A deep low pressure system in the North Atlantic is expected to reach maximum intensity off Iceland by Wednesday morning, battering that country with high winds and bringing yet more rain to the United Kingdom, which is already reeling from record floods. Expected to be one of the strongest storms — if not the strongest — ever recorded in this area of the North Atlantic, it’s at least partly a continuation of the same low pressure system that helped spawn tornadoes in Dallas on Saturday.

Heading north and east, that system is now rounding Greenland, pushing warm temperatures ahead of it and drawing high winds behind it, where it seems set to clash with a pair of low pressure systems already in the Atlantic.

Intense storms off Iceland and Greenland are not uncommon during winter; but, notes climate writer Andrew Freedman at Mashable, ”in a region famous for ship-sinking waves and relentless blizzards, this storm may stand out for its sheer intensity.”

One consequence of the storm system will be a surge of warmth northward from the Atlantic deep into the High Arctic. Temperatures at the North Pole — which, it’s worth remembering, is presently enveloped in 24 hour darkness — could reach 40 degrees F, warmer than Oklahoma City, El Paso, and southern California, and fully 50 degrees warmer than the seasonal average.

Large temperature fluctuations in the Arctic are relatively common, notes Freedman, but such an anomaly is “extreme.” Indeed, according to meteorologist Bob Henson at The Weather Underground, there have been only three instances since 1948 when North Pole temperatures have hit or exceeded the freezing mark in December, and none in January through March.

Such a high, even if for a short duration, could impact the formation of winter sea ice, at a time when sea ice levels in spring, summer and fall are already at historic lows as a result of climate change.

Last week, NOAA released the latest edition of its annual Arctic Report Card, in which it noted that 10 years ago “Arctic sea ice set a new record unlike anything previously observed. The 2015 low is 350,000 square miles below that. In fact, the nine lowest Arctic sea ice extents in the satellite record have all occurred in the last nine years.” This year’s sea ice minimum was the fourth smallest on record.

Read more at Discovery News

Christmas Trees Make Perfect Gift for Fish and Goats

Your Christmas tree looks enchanting when it’s decorated with tinsel, candy canes and glittering lights in your living room. But it looks anything but enchanting when it’s lying there on the curb outside your house on the day after New Year’s, waiting to go into a landfill.

But it’s possible to have the holiday spirit and be eco-friendly as well. Numerous communities across the nation are recycling discarded Christmas trees, some of them in ways that actually turn them into an environmental asset instead of a liability.

In West Virginia, for example, the state’s Division of Natural Resources and other agencies are collecting trees that will be re-purposed to as underwater habitat for fish, the Charleston Gazette-Mail reports.

Trees are also recycled as fish habitats in Louisiana, Ohio and other states. In Missouri, the U.S. Army Corps of Engineers began creating such underwater Christmas tree fish shelters back in the 1980s, according to Treehugger.

According to the U.S. Forest Service, after the trees are collected, they’re bundled together into groups of four our five, and then weighted down with concrete blocks and submerged into lakes, at varying depths. The bundles create an artificial reef that extends from the shore into deeper waters. That allows the trees to be utilized as shelter by a variety of fish, ranging from young fish who stay in shallow areas, to adults who go into the deep.

The species that benefit from the Christmas trees include crappies, bluegills and bass.

“Christmas trees make cheap, but quality underwater structures,” according to the Forest Service. “They are easy to place in the ponds and lakes, and they last for several years. More importantly, their branching patterns offer something to fish of all shapes and sizes.”

But fish aren’t the only creatures who benefit from Christmas tree recycling. In San Francisco, a company called City Grazing is partnering with the city’s Fire Department to accept trees and use them as goat food.

According to, the company has a herd of 80 animals, who will chow down on 160 Christmas trees.

Read more at Discovery News

Dec 28, 2015

Giant Squid Visits Harbor in Japan

Giant squid fans got a nice Christmas present, when one of the titans of the deep appeared in a Japanese harbor on Christmas Eve. Better still for those on hand, it hung around to let itself be recorded in some amazing footage, CNN reports.

The rarely seen aquatic behemoth paid a visit to Japan’s Toyama Bay, swimming near the surface among the harbor’s boats, and giving onlookers a thrill.

One of those watching the squid was a dive shop owner who leaped into the water to trail the creature. The footage above was caught by a submersible camera.

“This squid was not damaged and looked lively, spurting ink and trying to entangle his tentacles around me,” the diver told CNN.

The animal stayed in the harbor for a few hours, before the diver guided it back out to the ocean. It's likely a juvenile, as it was on the small side for the species, at about 12 feet long (adults can reach some 30 to 40 feet long).

Experts told the network that it was rare to see giant squid — normally denizens of the deepest seas — swimming so close inland among boat moors. There was no immediately clear reason why this one had done so.

Read more at Discovery News

Stem Cells May Save Northern White Rhinos

With only three northern white rhinoceroses left on Earth, conservationists are giving up on traditional breeding efforts and turning to cutting-edge science to save this subspecies.

At a meeting in Vienna from Dec. 3 to Dec. 6, researchers developed a plan to use stem cells to create fertilized rhino embryos, which will be carried by surrogate southern white rhino females.

This past year has been a sad one for northern white rhinos, a rapidly disappearing subspecies destroyed by habitat loss and poaching. There were six northern whites on the planet, all in captivity, in December 2014. That month, the second-to-last male, Angalifu, died at the San Diego Zoo. That left Sudan, a 42-year-old rhino at the Ol Pejeta Conservancy in Kenya, as the only northern white male rhino on Earth.

Next to go was 31-year-old Nabiré, a female who died of a ruptured cyst at the Dv?r Králové Zoo in the Czech Republic in July. An infection claimed Nola, a 41-year-old female at the San Diego Zoo, in November.

Now the only three remaining northern whites live at the Ol Pejeta reserve. Sudan still survives, but is too old to mount a female. And the two remaining females, Najin and Fatu, also have health problems that prevent them from reproducing the old-fashioned way.

So scientists plan to collect egg and sperm cells from the last living northern whites and combine them with induced pluripotent stem cells (iPS cells). These are cells taken from the rhino’s body and chemically induced to turn back the clock to an earlier developmental phase, when cells are capable of becoming many different types of body tissue. The hope is that scientists can reverse-engineer body cells into sperm and egg cells. Fertilized embryos could then be made by in vitro fertilization (IVF) and transferred into southern white rhinoceroses, the northern white’s nearest relative.

But there are complications to this plan: No one has ever successfully completed IVF on a rhino of any species. Every species requires its own cell-culture conditions to mimic the unique environment of the uterus, Barbara Durrant, director of reproductive physiology at the San Diego Zoo Institute for Conservation Research, told Live Science in June. Depending on how long it takes to make the breakthroughs necessary to create rhino embryos in a lab, the species could go extinct before scientists successfully breed new individuals.

Read more at Discovery News

Egyptian Statues Revealed in Ancient Shrines

Six rock cut statues have been discovered within 18th Dynasty shrines in Egypt, Antiquities Minister Mamdouh el-Damaty announced.

The 3,400-year-old statues were found at Gebel el Sisila, a site north of Aswan known for its stone quarries on both sides of the Nile. Blocks used in building almost all of ancient Egypt's great temples were cut from there.

The statues were carved within two of the 32 shrines erected by the officials who were in charge of quarrying the stone.

The two shrines are located about half a mile south of Gebel el Sisila’s most famous monument, the rock-cut temple known as the Speos of Horemheb. In antiquity they suffered some fracturing due to earthquakes, and erosion due to their submersion by the Nile during the flood season.

“The shrines were described as almost completely destroyed,” el-Damaty said.

On the contrary, a Swedish mission from Lund University, led by Maria Nilsson, found the chapels, known as shrine 30 and shrine 31, preserved in their entirety.

Nilsson worked in cooperation with the inspectorate of Kom Ombo under General Director Abd el Menum, and the inspectorate of Aswan under General Director Nasr Salama.

Shrine 30 featured intact architectural elements, such as the doorway with its lintel, door jamb, threshold, interior walls and ceiling.

At the back of the shrine, within a niche, the archaeologists found two life-size statues.

“They show a male and a female seated on a couch, positioned slightly towards each other in a private embrace,” Nilsson said.

The male figure, and owner of the shrine, is portrayed with enlarged and protruding ears, large nose and lips, and sunken eyes. His arms are crossed over his chest, in the so-called Osirian position, and he wears a shoulder-length hair wig.

Portrayed with equally pronounced facial features, the female statue embraces the male, one arm placed on the male’s shoulder, and the other hand in front of her chest.

“We have no clues so far about the identity of this couple. Unfortunately there is no information preserved within the hieroglyphic text,” Nilsson told Discovery News.

Nilsson’s team also found that the other monument, known as Shrine 31, had retained all its original architectural details, including its threshold, floor, door jambs and internally dressed walls.

“The shrine in fact is the best preserved of all 32 cenotaphs at Gebel el Silsila,” associate director John Ward said.

Seated and placed within a niche, the archaeologists found four well-preserved statues, two male and two females.

“The main male figure, depicted with his arms in the Osirian position, is the owner of the shrine, Neferkhewe,” Nilsson and Ward said.

Active during the reign of Thutmosis III, Neferkhewe is described within the shrine as “the overseer of the foreign lands” and “chief of the medjay (a region in northern Sudan).”

He wears a shoulder-length wig and is also portrayed with enlarged ears, sunken eyes large nose and lips, all set within a rounded face.

Neferkhewe’s wife, Ruiuresti, sits to the far left. Boasting facial features similar to those of her husband, she is portrayed with her arm around his Neferkhewe, holding an object in her other hand.

The two remaining statues, seated on the right side, likely portray the couple’s children, a daughter and a son.

According to the archaeologists these two carvings were remodeled during antiquity due to severe damage caused by fracturing to the sandstone.

“The statues are very finely carved, but were damaged and rubbed down by the tides of the water and years of being packed under silt,” Nilsson said.

Preliminary results of the translations of the hieroglyphic texts and titles indicate that the names of the two children are not previously known.

“The identity of the son is not that of the famous son of Neferkhewe and Ruiuresti, Menkheperresonb, who is known from other sources,” Nilsson and Ward said

The archaeologists also discovered relief scenes on both the northern and the southern walls of Shrine 31.

Read more at Discovery News

Rocky Exoplanet Found Orbiting 'Most Anemic' Star

How low can you go? Astronomers have found a star with an incredibly low concentration of heavy elements that still has a sizable planet around it — the most metal-poor star ever discovered with an orbiting, rocky planet.

The planet found circling the unlikely star suggests that other Earths could be more common than once thought.

A team led by Annelies Mortier, an exoplanet researcher at the University of St. Andrews in the United Kingdom, found the star, called HD175607, and its Neptune-size planet about 147 light-years from Earth, using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph in Chile. The star is a yellowish dwarf, with about 0.74 times the mass of the sun, and it contains fewer heavy elements than any other star of its kind that has rocky planets. The ratio of iron to hydrogen, for example, is only 23 percent that of the sun's.

To make planets, you need elements heavier than hydrogen and helium. In astronomical parlance, these elements are known as metals, even though they include substances like oxygen, silicon and carbon. Astronomers can measure a star's metallicity, or the ratio of heavy elements to hydrogen, by looking at the wavelengths of light coming from the star and comparing its metal content to the surrounding regions of the galaxy. The metallicity of a star also tells you what was likely in the cloud of gas and dust that formed it in the first place.

Researchers generally expect stars with high metallicity to be more likely to have giant planets like Jupiter — in fact, astronomers target such stars in order to boost the odds of seeing a planet, Mortier told in an email. But for rocky, Neptune-size planets and those that are smaller, that correlation doesn't appear to hold. That's why the HARPS is looking at low-metallicity stars to see how low that ratio can go before the star no longer has planets at all.

"For Neptunes and Earthlike planets, it is not as clear yet what the role of metallicity is," Mortier said.

In this case, the star HD175607 appears to have a planet orbiting it at a distance that's about a third of Mercury's to the sun. It completes a "year" of orbit in 29 days and weighs between 7.88 and 10.08 times as much as Earth, putting it at about two-thirds the mass of Neptune — which has a mass that's about 17 times that of Earth's.

Planets are hard to see to begin with; finding the one around HD 175607 took months of observations spread out over nine years. The researchers had a much easier time measuring the star's metallicity.

Read more at Discovery News