Mysterious Toe Rings Found on Ancient Skeletons

Archaeologists have discovered two ancient Egyptian skeletons, dating back more than 3,300 years, which were each buried with a toe ring made of copper alloy, the first time such rings have been found in ancient Egypt.

The toe rings were likely worn while the individuals were still alive, and the discovery leaves open the question of whether they were worn for fashion or magical reasons.

Supporting the magical interpretation, one of the rings was found on the right toe of a male, age 35 to 40, whose foot had suffered a fracture along with a broken femur above it.

Unique Rings in a Unique Ancient City

Both skeletons were found in a cemetery just south of the ancient city of Akhetaten, whose name means "Horizon of the Aten." Now called Amarna, the city of Akhetaten was a short-lived Egyptian capital built by Akhenaten a pharaoh who tried to focus Egypt's religion around the worship of the sun disc, the "Aten." He was also likely the father of Tutankhamun.

After Akhenaten's death, this attempt to change Egyptian religion unraveled, as his successors denounced him and the city became abandoned. Even so, Anna Stevens, the assistant director of the Amarna Project, said the newly discovered rings are unlikely to be related to the religious changes Akhenaten introduced.

The findings do appear to be the first copper alloy toe rings discovered in ancient Egypt. "I'm not aware of any, but that doesn't mean they don't exist. Bear in mind that if we found something like this in a house, for example, we would have no idea of its purpose," Stevens wrote in an email to LiveScience.

A gold toe ring was previously found on a mummy named Hornedjitef, a priest at Karnak more than 2,200 years ago. The mummy, which resides at the British Museum, has a "thick gold ring on the big toe of his left foot," writes anthropologist Joyce Filer in her book "The Mystery of the Egyptian Mummy" (British Museum Press, 2003).

A Magical Healing Device?

The man whose right foot had been injured was likely in great pain when alive.

He "showed signs of multiple antemortem [before his death] fractures, including of several ribs, the left radius, right ulna, right foot (on which the toe ring was found) and right femur," Stevens wrote. "The fracture of the right femur healed at an angle and must have caused this individual considerable ongoing pain."

The ring was placed on the toe of the injured foot, suggesting perhaps it was intended as a magical healing device of sorts.

"The act of 'binding' or 'encircling' was a powerful magical device in ancient Egypt, and a metal ring, which can be looped around something, lends itself well to this kind of action," Stevens said. "This is a possibility that we will look into further, checking through sources such as the corpus of magico-medical spells that have survived from ancient Egypt, to look for parallels."

However, the skeleton of the second individual with the toe ring, found in 2012, bore no visible signs of a medical condition. Stevens notes that this individual has yet to be studied in depth by bio-archaeologists and its sex is unknown.

Who Were They?

The skeletons were wrapped in textile and plant-stem matting, and both burials had been disturbed by tomb robbers.

None of the skeletons in the cemetery were technically "mummified" so to speak. "There is no evidence from the cemetery as a whole of attempts to mummify the bodies, in terms of the removal of internal organs (we quite often find remains of brain within the skulls) or the introduction of additives to preserve tissue (the bodies survive largely as skeletons)," Stevens wrote. "But in a way the wrapping of the bodies within textile and matting is a step towards preserving the shape of the body, and a form of simple mummification."

Figuring out who these individuals were in life is tricky, Stevens said. This cemetery appears to represent a "wide slice" of the city's society. These people were not wealthy enough to get buried in a rock-cut tomb but could afford, and were allowed, the simple burials seen at this cemetery.

"They [the two individuals] probably lived, like most citizens of Amarna, in a small house adjacent to that of a larger villa belonging to one of the city's officials, for whom they provided services and labor in exchange for basic provisions, especially grain," Stevens said.

Read more at Discovery News

Decoding the Higgs Boson: Is it the Real Deal?

On July 4, 2012, physicists announced the groundbreaking discovery of a subatomic particle that was “consistent” with the Higgs boson. Using data from two Large Hadron Collider (LHC) experiments — CMS and ATLAS — something with the approximate energy of the theoretical particle had been spotted.

“We have observed a new boson,” announced Joe Incandela, CMS lead physicist, to cheers from the audience at the special meeting in Geneva, Switzerland. Had the final piece of the Standard Model finally been found? Was this the end of physics as we knew it?

A year after that historic day, physicists are still trying to characterize this “new boson,” and although it certainly looks like the much sought-after Higgs boson, can the quantum hunt finally be laid to rest?

Well, in typical particle physics style, scientists are still working on it.

“We have established without a doubt that we have a new particle, and that it is a boson. What remains to be done is confirm that it is a Higgs,” said physicist Pauline Gagnon, CERN physicist and member of the 2012 discovery team.

Wait, we’re still waiting for “confirmation”?

The Higgs boson is the last piece of the Standard Model — the all-encompassing theory that describes the nature of subatomic particles in our Universe. Theorized by a team of physicists in the 1960′s, headed by Peter Higgs, the particle has been the focus of increasingly powerful particle accelerators. The 7.5 billion euro ($9.5 billion) LHC on the Franco-Swiss border was built, in part, to find the Higgs boson.

Investing all this time, energy and money into seeking out a subatomic particle has created the most complex experiment in human history, all in an effort to understand one of the most fundamental puzzles in physics. The Higgs boson is an “exchange particle” that endows all matter with mass; without it, the Universe as we know it wouldn’t exist. In short, for the Standard Model to be correct, the Higgs must exist, otherwise quantum physics is wrong and a revolution in physics awaits. (Physicists love physics revolutions, so not every scientist was overjoyed to find a boson exactly where the Higgs boson should be hiding.)

Since last year’s big announcement, the complex problem of characterizing the candidate particle has kept LHC physicists busy. Though a boson certainly exists at the energy level predicted for a Higgs boson, it’s not necessarily the Higgs boson. Some physicists support the idea that there is just one type of Higgs boson, whereas superstring theory proponents reckon there is at least five.

“Have we found the boson, or perhaps one of several predicted by other theories? Until now, everything indicates that this is the Standard Model boson,” Gagnon told the AFP news agency. “It has the allure, the look, the song and the dance of the Higgs boson.”

Indeed, shortly after the detection of the “new boson,” physicists had to work on understanding the other physical characteristics of the particle. To be a Higgs boson, the particle must have zero spin and positive parity. “Spin” is a quantum measurement of angular momentum and “parity” is a measure of how a quantum particle’s mirror image behaves. After analyzing 2.5 times more data than was available last year, physicists in March announced that their Higgs candidate had “no spin and positive parity.” So far, so good.

The more analysis that is done, the more it seems that the boson is looking like a bona fide Higgs. But some physicists are still trying to rule out the possibility that they are being duped by nature while others aren’t convinced that they’ll ever be able to say that this Higgs is the one and only Higgs.

Read more at Discovery News

Seeing Sea Stars: The Missing Link in Eye Evolution?

A study has shown for the first time that starfish use primitive eyes at the tip of their arms to visually navigate their environment. Research headed by Dr. Anders Garm at the Marine Biological Section of the University of Copenhagen in Denmark, showed that starfish eyes are image-forming and could be an essential stage in eye evolution.

The researchers removed starfish with and without eyes from their food rich habitat, the coral reef, and placed them on the sand bottom one metre away, where they would starve. They monitored the starfishes' behaviour from the surface and found that while starfish with intact eyes head towards the direction of the reef, starfish without eyes walk randomly.

Dr Garm said: "The results show that the starfish nervous system must be able to process visual information, which points to a clear underestimation of the capacity found in the circular and somewhat dispersed central nervous system of echinoderms."

Analysing the morphology of the photoreceptors in the starfish eyes the researchers further confirmed that they constitute an intermediate state between the two large known groups of rhabdomeric and ciliary photoreceptors, in that they have both microvilli and a modified cilium.

Dr Garm added: "From an evolutionary point of view it is interesting because the morphology of the starfish eyes along with their optical quality (quality of the image) is close to the theoretical eye early in eye evolution when image formation first appeared. In this way it can help clarify what the first visual tasks were that drove this important step in eye evolution, namely navigation towards the preferred habitat using large stationary objects (here the reef)."

Most known starfish species possess a compound eye at the tip of each arm, which, except for the lack of true optics, resembles arthropod compound eye. Despite being known for about two centuries, no visually guided behaviour has ever been documented before.

From Science Daily

New Insights Into the Early Bombardment History On Mercury

The surface of Mercury is rather different from those of well-known rocky bodies like the Moon and Mars. Early images from the Mariner 10 spacecraft unveiled a planet covered by smooth plains and cratered plains of unclear origin. A team led by Dr. Simone Marchi, a Fellow of the NASA Lunar Science Institute located at the Southwest Research Institute (SwRI) Boulder, Colo., office, collaborating with the MESSENGER team, including Dr. Clark Chapman of the SwRI Planetary Science Directorate, studied the surface to better understand if the plains were formed by volcanic flows or composed of material ejected from the planet's giant impact basins.

Recent images from NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft provided new insights showing that at least the younger plains resulted from vigorous volcanic activity. Yet scientists were unable to establish limits on how far into the past this volcanic activity may have occurred, or how much of the planet's surface may have been resurfaced by very old volcanic plains.

Now, a team of scientists has concluded that the oldest visible terrains on Mercury have an age of 4 billion to 4.1 billion years, and that the first 400 to 500 million years of the planet's evolution are not recorded on its surface. To reach its conclusion, the team measured the sizes and numbers of craters on the most heavily cratered terrains using images obtained by the MESSENGER spacecraft during its first year in orbit around Mercury. Team members then extrapolated to Mercury a model that was originally developed for comparing the Moon's crater distribution to a chronology based on the ages of rock samples gathered during the Apollo missions.

"By comparing the measured craters to the number and spatial distribution of large impact basins on Mercury, we found that they started to accumulate at about the same time, suggesting that the resetting of Mercury's surface was global and likely due to volcanism," said lead author Dr. Simone Marchi, who has a joint appointment between two of NASA's Lunar Science Institutes, one at the SwRI in Boulder and another at the Lunar and Planetary Institute in Houston.

Those results set the age boundary for the oldest terrains on Mercury to be contemporary with the so-called Late Heavy Bombardment (LHB), a period of intense asteroid and comet impacts recorded in lunar and asteroidal rocks and by the numerous craters on the Moon, Earth, and Mars, as well as Mercury.

"Meanwhile, the age of the youngest and broadest volcanic provinces visible on Mercury was determined to be about 3.6 billion to 3.8 billion years ago, just after the end of the Late Heavy Bombardment," Marchi said.

Read more at Science Daily

The Great British Alien Hunt Begins?

The Search for Extraterrestrial Intelligence, or SETI, is one of the most profound — yet speculative — scientific pursuits of this generation. There is no evidence that any extraterrestrial life exists in our galactic neighborhood, yet we still try to ‘listen’ out for a sufficiently advanced alien race across the interstellar void. And now the SETI effort won’t be restricted to US-managed radio antennae — the British are joining the hunt.

Currently, SETI efforts are funded by private donations, but the UK SETI Research Network (UKSRN), comprised of scientists from 11 institutions, is eying government funds to give their search a turbo-boost.

“If we had one part in 200 — half a percent of the money that goes into astronomy at the moment — we could make an amazing difference. We would become comparable with the American effort,” said Alan Penny, UKSRN coordinator and researcher at the University of St Andrews, in an interview with BBC News. The UKSRN carried out their first meeting at the National Astronomy Meeting (NAM2013) at St. Andrews, Scotland, on Friday (July 5).

“I don’t know whether (aliens) are out there, but I’m desperate to find out. It’s quite possible that we’re alone in the Universe. And think about the implications of that: if we’re alone in the Universe then the whole purpose in the Universe is in us. If we’re not alone, that’s interesting in a very different way.”

“There are billions of planets out there. It would be remiss of us not to at least have half an ear open to any signals that might be being sent to us,” added Tim O’Brien of Jodrell Bank, a radio antennae that has been used for SETI projects in the past.

The network is applying for one million pounds ($1.5 million) per year for time on radio telescopes and data analysis.

Sadly, justifying public funds to back a project with no definite final outcome can be a tricky proposition, especially in the existing climate of government science cuts and fiscal woes. It therefore seems difficult to see why the Science and Technology Facilities Council (STFC), the primary funding body of UK science and technology, would support such an effort.

“Continued flat-cash science budget awards are constantly eroding STFC’s buying powers, causing the UK to withdraw from existing productive facilities such as the United Kingdom Infrared Telescope and the James Clerk Maxwell Telescope,” said Paul Crowther of Sheffield University. “(British astronomy) faces the prospect of a reduced volume of research grants, and participation in future high-impact facilities is threatened. I would be shocked if STFC’s advisory panels rated the support of UKSRN higher than such scientifically compelling competition.”

But in an ideal universe, where science receives the funding it deserves, justifying money on the hunt for intelligent extraterrestrials isn’t such a hard-sell.

For starters, analyzing radio antennae data for artificial signals isn’t such a resource-heavy project. Using existing radio antennae and groups of antennae (hooked up as interferometers), SETI projects can “piggyback” on surveys being carried out by other research groups and vice versa. Also, the development of technologies to whittle out artificial messages from cosmic noise will have tangible benefits for radio astronomy and communications techniques.

And then there’s the public interest in SETI projects. Undoubtedly there will be those who see any SETI effort a waste of time, but to be at the level of intelligence and technological know-how to actually conceive the prospect of life on Earth not being the only life in our galaxy is a profound philosophical epoch for the evolution of our species.

As embodied in the privately-funded Lone Signal project that was launched last month, the public interest in “reaching out” to the stars appears to be unwavering. Lone Signal is a Messaging Extraterrestrial Intelligence (METI) project that aims to be active for many decades, beaming crowd-sourced messages to the stars in the hope that some benevolent ETI is listening and asking the same questions we are.

Of course, as with any METI effort, whether we should be beaming “proof of life” radio waves to nearby stars at all is questionable — who knows if the Milky Way’s inhabitants are friendly? We could be living in a interstellar ecosystem where humanity is a mere ants nest. Should we really be transmitting our presence in spite of the risk of getting trampled?

Alternatively, should we endeavor to be “radio silent,” and risk a lonely existence, never to make contact with that neighboring, yet invisible, hypothetical alien civilization?

Read more at Discovery News

Save Your Pennies: Copper Blocks Fish Sense

When Frank Sinatra threw “three coins in a fountain,” Old Blue Eyes may have endangered fish swimming in those waters. In an experiment, copper-contaminated waters blocked fishes’ ability to smell the odor released by other fish when in danger.

However, people willing to spend a bit more on their wishes don’t stifle fishes’ senses. The metal nickel didn’t seem to block the detection of danger signaling scents released by fish during a predator attack.

“Our research shows that copper affects the function of a specific type of olfactory neurons in fish, preventing them from detecting important olfactory signals used to detect fish injured by predation,” said Bill Dew of the University of Lethbridge in Canada in a press release. “This means that fish in an environment contaminated with copper would not be able to detect compounds released during a predation event and potentially not avoid predators, while fish in a nickel contaminated environment would be able to detect these compounds and undertake predator-avoidance behaviors.”

Dew used fathead minnows in his experiment. Dew’s study will be presented today at a meeting of the Society for Experimental Biology.

Copper contamination can occur when hopeful humans toss pennies into natural wells. For example, in Bermuda, tourists make wishes before throwing coins into deep cave pools filled with salty water, reported the National Oceanic and Atmospheric Administration. The copper in the coins dissolves rapidly in salt water and results in toxic levels of copper in the pools.

Copper mining and its byproducts can contaminate water with copper, as well. Copper mines and waste from the operations can pollute water with so much metal that the water turns turquoise blue. Runoff of copper-based fungicides from farms and vineyards also can pollute waterways.

Read more at Discovery News

Earliest Evidence of Using Flower Beds for Burial Found in Raqefet Cave in Mt. Carmel

The earliest evidence of using flower beds for burial, dating back to 13,700 years ago, was discovered in Raqefet Cave in Mt. Carmel (northern Israel), during excavations led by the University of Haifa. In four different graves from the Natufian period, dating back to 13,700-11,700 years ago, dozens of impressions of Salvia plants and other species of sedges and mints (the Lamiaceae family), were found under human skeletons.

"This is another evidence that as far back as 13,700 years ago, our ancestors, the Natufians, had burial rituals similar to ours, nowadays," said Prof. Dani Nadel, from the University of Haifa, who led the excavations.

The Natufians, who lived some 15,000-11,500 years ago, were of the first in the world to abandon nomadic life and settle in permanent settlements, setting up structures with stone foundations. They were also among the first to establish cemeteries -- confined areas in which they buried their community members for generations. The cemeteries were usually located at the first chambers of caves or on terraces located below the caves. In contrast, earlier cultures used to bury their dead (if at all) randomly. Mt. Carmel was one of the most important and densely populated areas in the Natufian settlement system. Its sites have been explored by University of Haifa archeologists for dozens of years.

A Natufian cemetery containing 29 skeletons of babies, children and adults was discovered at Raqefet cave. Most of the burials were single interments, although some were double, in which two bodies were interred together in the same pit. In fours graves, researchers found plant impressions on a thin layer of mud veneer which was presumably spread like plaster inside the grave. Before burying the bodies, the Natufians spread a bed of blooming green plants inside the graves. The impressions are mostly of plants with square stems, common among the mint family. In one incident, flowering stems of Judean Sage were found, one of three Sage species currently growing in the vicinity of the cave. This led the researchers to suggest that the burials were conducted in springtime, using colorful and aromatic flowers. The Raqefet cave remains are the earliest example found of graves lined with green and flowering plants.

According to the researchers, apparently flowerbeds were not restricted to adults alone and graves of children and adolescents were also lined with flowers. Since the mud veneer doesn't include impressions of stone objects and bones, despite the presence of thousands of these hard and durable artifacts within the cave and grave fills, the researchers suggest that the green lining was thick and continuous, covering the entire grave floor and sides, preventing objects from leaving impressions on the moist mud veneer.

The researchers even found evidence of Natufian bedrock chiseling in the graveyard, demonstrating grave preparation to fit their needs. The Natufians also chiseled a variety of mortars and cupmarks in close vicinity to the graves and on rock exposures on the terrace below the cave. The graves were directly radiocarbon dated. Samples from three different human skeletons were dated to 13,700-11,700 years ago.

"The Natufians lived at a time of many changes -- a time when population density was rising and the struggle for land, food and resources was increasing. The establishment of grave yards and unique burial rituals reflects the complexity of the Natufian society. Communal burial sites and elaborate rituals such as funeral ceremonies must have strengthened the sense of solidarity among the community members, and their feeling of unity in the face of other groups," concluded Prof. Nadel.

The project was led by researchers from the Zinman Institute of Archaelogy at the University of Haifa, with expert partners from the Hebrew University of Jerusalem, the Weizmann Institute, the Max Planck Institute (Germany), The Centre National de la Recherche Scientifique (Paris) and the Anthropology Department at the University of Texas at Austin (USA). The research results were published in the Proceedings of the National Academy of Sciences.

Read more at Science Daily

Farming Sprang Up In Multiple Places

In the dry foothills of Iran’s Zagros Mountains, a new picture of mankind’s first farmers is emerging from an archaeological dig that has turned up a jackpot of artifacts and plant grains.

People who lived in the region began cultivating cereal grains as early as 11,700 years ago, according to the new analysis, which adds Iran to the list of places in the Near East where the first inklings of farming emerged just after the end of the last Ice Age.

Once people figured out how to cultivate, and then domesticate, plants and animals, they eventually developed settlements and agricultural economies that formed the foundation of modern civilizations, said Nicholas Conrad, head of the archaeological team that made the new discoveries.

Along with previous work in nearby regions, the new study suggests that farming began simultaneously over a widespread area, offering an important window into a pivotal time in human history.

“There is not just one village where you can say, ‘This is where domestication occurred,’” said Conrad, of the University of Tübingen in Germany. “It wasn’t as if the development of agriculture was like someone flipped a light in one place and from that point of origin, agriculture spread. It’s a process that occurred in a whole range of places.”

The study of farming’s origins have long focused on a region known as the Fertile Crescent, which encompasses the land around modern-day Syria, Israel, Jordan, Turkey and Iraq. When the last Ice Age ended around 12,000 years ago, the Fertile Crescent’s climate and terrain became ripe for crops to grow. Previous digs have turned up evidence of the very beginnings of cultivation in a handful of sites in the western part of that region.

In 2009 and 2010, archaeologists were finally able to excavate a site called Chogha Golan at the base of Iran’s Zagros mountains on the eastern edge of the Fertile Crescent, much further east than previous searches for evidence of early farming.

As they dug through 26 feet of sediment dating back nearly 12,000 years, the researchers unearthed an amazing array of artifacts, including clay figurines, animal bones, ornaments, mortars, grinding tools and signs of burials. The sequence of objects and materials showed that fairly large groups of people lived in the area between 12,000 and 9,800 years ago, the researchers report today in the journal Science.

For the new study, which is likely to be the first of many that will emerge from the site, Conrad and colleagues focused on an extraordinarily rich bounty of botanical remains, including grains of barley and wheat. Out of 717 collected samples, the new paper reports on analyses of just 25, Conard said, which turned up 21,000 plant remains.

Over 2,000 years of prehistoric living, changes in the structure of plant remains allowed the team to see progress from crude plant management to true domestication. In the earliest days of occupation at the site, people were planting wild varieties of barley, wheat, lentils, grass peas and other plants. Over time, the part of the plants where the grains attach changed in ways that suggest people began breeding and domesticating the crops to be better for harvesting and processing.

The new discoveries push eastward the boundaries of the region where experts now think agriculture began, said George Wilcox, an archaeologist at the French National Center for Scientific Research and the University of Lyon.

Without a written record, no one can say whether ideas spread from population to population at the time or if people migrated, bringing crops and knowledge with them. It’s also possible that different groups of people came up with the same ideas around the same time.

Whatever the details, the new work suggests that there was no single point where farming began.

Read more at Discovery News

Mystery Intergalactic Radio Bursts Detected

Astronomers were on a celestial fishing expedition for pulsing neutron stars and other radio bursts when they found something unexpected in archived sky sweeps conducted by the Parkes radio telescope in New South Wales, Australia.

The powerful signal, which lasted for just milliseconds, could have been a fluke, but then the team found three more equally energetic transient flashes all far removed from the galactic plane and coming from different points in the sky.

Analysis later indicated that, unlike most cosmic radio signals that originate in the Milky Way or a nearby neighbor galaxy, these four seem to have come from beyond.

Whatever triggered the bursts has come and gone. The signals, detected between February 2011 and January 2012, were one-time events so little follow-up work can be done.

What is known is that in just a few milliseconds, each of the signals released about as much energy as the sun emits in 300,000 years.

“They have come such a long way that by the time they reach the Earth, the Parkes telescope would have to operate for 1 million years to collect enough to have the equivalent energy of a flying mosquito,” astronomer Dan Thornton, with the University of Manchester in the United Kingdom, wrote in an email to Discovery News.

Scientists have all kinds of theories about what exotic phenomena may have triggered the bursts. The contenders include colliding magnetars, which are neutron stars with super-strong magnetic fields; evaporating black holes; and gamma ray bursts that involve a supernova.

Or, as Cornell University astronomer James Cordes points out, the bursts could be from an entirely new type of high-energy astrophysical event.

“It is still early days for identifying the astrophysical origins of such common but (so far) rarely detected events,” Cordes wrote in an article published in this week’s Science.

Whatever is happening is probably a relatively common, though difficult to detect, phenomenon. Extrapolating from the research, astronomers estimate there are as many as about 10,000 similar high-energy millisecond radio bursts happening across the sky every day.

“This might seem common, and it is, but you need a big telescope to detect them,” Thornton said.

Typically, telescopes only look at a very small patch of the sky at any one time, he added, “so you have to look for a long time before seeing many. This is why we have only detected a handful so far.”

Similar radio signals have been found before, but astronomers could never nail down whether they came from inside or beyond the galaxy.

Read more at Discovery News

White Dwarf Morphs into Massive Pulsing Crystal

Astronomy lets us peer into some of the strangest corners of physics in a way that are incredibly hard (or impossible) to reproduce in a laboratory setting. For example, a recent discovery of pulsations from a massive white dwarf star has allowed astronomers to imagine a crystallized, semi-solid ball of oxygen and neon the size of our planet.

To understand where white dwarfs come from, you must first look at the evolution of “normal” or main-sequence stars. These begin their lives by fusing hydrogen into helium in their cores, powering the heat and light of the star as some of the mass of that interaction is turned into energy. For most stars, the core will eventually reach a state when there is not enough hydrogen in the core for this process to continue, and the star evolves and eventually dies.

For a star with the mass of our sun, helium can undergo nuclear fusion eventually creating carbon and oxygen for a short time. Stars more massive than the Sun will do this as well, and those with seven times the sun’s mass will even achieve stable carbon fusion to produce neon. However, for such stars, that’s the limit, and once that fusion process has run down, the nuclear power plant at the center shuts down and the outer layers of the star are lost to interstellar space. What is left behind is the former core of the star, now called a white dwarf.

A white dwarf is an extremely dense and hot ember of a star. Typical white dwarf masses are a little more than half the mass of our sun. There is great astrophysical interest, however, in the higher mass white dwarfs, since these are the ones that create novae and even Type 1a supernovae, which have become an important tool for measuring the acceleration of the Universe.

A team using the 2.1-meter telescope at McDonald Observatory in Texas set out to find and characterize these high mass white dwarf stars. They came across GD 518, which by its spectrum was shown to have a surface temperature of 12,000 degrees Celsuis, twice the temperature of the surface of our sun. The mass was determined by looking at the absorption lines in the spectrum due to hydrogen. These were wide lines, “distorted” by a high surface gravity nine times that of what we feel at Earth’s surface. This indicates that it has a mass of 1.2 times the mass of the sun and, according to stellar models, should be made of oxygen and neon.

Since astronomers can’t go out and sample the interior of a star, they need other methods for understanding what is inside. In addition to the theoretical models, the remnants of bright novae, or partially exploded white dwarf stars, have shown oxygen, carbon, and other such materials left behind. But the group in Texas were looking for pulsations, or variability in these high mass white dwarfs.

So, with careful observations, they discovered that GD 518 was indeed varying in brightness on a time scale of six to ten minutes. Variable stars change brightness because they actually “pulse,” expanding and contracting ever so slightly because of some instability inside the star. Predictions of white dwarf pulsations depend also on how much of the interior has crystallized, or solidified. The scale of these pulsations of GC 518 indicate that a significant fraction of its oxygen-nitrogen interior is in this crystal state.

This careful following of clues using just the light of the star, coupled with predictions of the physics of stars, thus leads us to the conclusion that in this faint, hot white dwarf star, we are seeing the crystallized remains of what was once a large, brightly burning star, yet one not quite large enough to blow itself apart in a supernova. The continued study of these rare white dwarfs will provide insight into other types of supernovae, however, and ensure that we’re making the right measurements of the Universe on the largest scales.

Read more at Discovery News