How Early Earth Got Its Nitrogen

Nitrogen may have arrived on Earth in ancient meteorites after the planet had already formed, according to a new study.

Reported in the journal Nature Geoscience, the research illustrates how meteorites -- often portrayed as portents of doom and destruction -- may actually have been key to the development of life on Earth.

Scientists have long puzzled over the origin of Earth's nitrogen because it has a different isotopic composition to nitrogen produced by the sun, and is also different to the nitrogen found in comets.

"For a long time there had been a theory that comets brought water and nitrogen to Earth, but there is growing evidence that the isotopic ratios in comets are very different to that in Earth's atmosphere," said the study's lead author Dennis Harries of the Friedrich-Schiller-Universität in Jena, Germany.

The authors used an electron microscope to study crystals from two ancient carbonaceous chondrite meteorites named Yamato-791198 and Yamato-793321 which were recovered from Antarctica in 1979. They discovered an unusual mineralized form of nitrogen which matched Earth's nitrogen.

"We found nitrogen with a similar isotopic composition to nitrogen found in people and in Earth's atmosphere, in a very unusual mineral which was detected in two meteorites," said Harries. "This mineral shows us that there was another type of nitrogen in the early solar system billions of years ago, and this molecule was probably responsible for making the building blocks of life and bringing the nitrogen of our atmosphere to Earth."

"The discovery of this mineralized form of nitrogen is telling us something about how Earth got its nitrogen."

Strange discovery

The meteorites examined by the authors contained a strange mineral called carlsbergite which is a compound of chromium and nitrogen.

"That's unusual because nitrogen is usually found as a gas in our atmosphere and is reluctant to enter mineral crystal structures," said Harries.

The authors discovered the carlsbergite by using an electron microscope to study crystals from the meteorites,

"The crystals we're looking at are only 100 nanometers in size, so they're not visible to the naked eye," said Harries.

They then used mass spectrometry to measure the isotopic composition of the nitrogen atoms in these very small mineral grains.

How it formed

Harries believes there were high concentrations of ammonia in some parts of the solar nebula which formed the Sun and solar system 4.6 billion years ago. Under the right conditions, nitrogen can be produced out of molecules of ammonia.

"We think the ammonia was locked up with water in ices and was somehow evaporated by shock waves, or by collisions of small bodies near the inner solar system," said Harries.

This generated extremely high temperatures causing the ammonia to react with minerals, forming carlsbergite.

Harries speculates that the asteroids containing carlsbergite were flung into the inner solar system by gravitational perturbations caused by changes in the orbit of Jupiter early in the solar system's history. Eventually some of these asteroids impacted the Earth.

Most of the original bodies containing these ices would now be gone, but Harries thinks some ice could still be found when NASA's Dawn spacecraft enters orbit around the main asteroid belt dwarf planet Ceres on March 7, 2015

Read more at Discovery News

200-Year-Old Map Changed How We See the World

Before the early 1800s, people probably didn’t think that much about what was under the ground upon they walked. But in 1815, a British surveyor, canal engineer and fossil enthusiast named William Smith helped change all that.

Smith published ”A Geological Map of England and Wale and Part of Scotland.” On a scale of 5 miles per inch, the map measured 6 feet by 8 feet 6 inches, and it was the first map that showed a detailed, multicolor three-dimensional depiction of the varieties of soil and layers of rock under a large area, as well as the location of mineral wealth and fossils. Smith used watercolors and devised an innovative shading technique that is still used in geological maps.

According to this biographical profile of Smith, the map’s creator was born in 1769 and grew up on his uncle’s farm, where as a child he became fascinated with what people called “poundstones,” which actually were ancient fossilized sea urchins. As a young man, he began working as a surveyor in coal mines, where he observed rock layers in predictable sequences and began to suspect that the strata extended across the countryside.

He gathered further evidence of his notion as he traveled around England, working as a surveyor on the canals that were being dug to transport the coal. He also discovered that different layers had different fossils in them. That led Smith to develop the principle of faunal succession, which is still used by scientists today to identify various rock strata.

The conceptual breakthrough inspired him to create his famous map.

While Smith’s work earned him a place in history, oddly, it also contributed to his financial ruin. Though he made a lot of money as a surveyor, Smith invested unwisely in real estate, and got so heavily into debt that he had to sell his famed collection of fossils to the British Museum. The map was a chance for him to get in the black again, but it didn’t sell well enough, in part because another surveyor published his own competing version. As a result, the creator of the first great geological map ended up in debtor’s prison in 1819.

From Discovery News

Why Sleep Paralysis Can Make You See Ghosts

It was an ordinary night, but Salma, a 20-year-old student at The American University in Cairo, had a particularly frightening experience. She woke up, unable to move a muscle, and felt as though there were an intruder in her bedroom. She saw what appeared to be a fanged, bloody creature that looked like "something out of a horror movie," standing beside her bed.

She later explained her experience to researchers who were conducting a survey about sleep paralysis, a common but somewhat unexplained phenomenon in which a person awakens from sleep but feels unable to move. Up to 40 percent of people report experiencing sleep paralysis at some point in their lives, and a few, like Salma, hallucinate shadowy intruders hovering over them.

"Sleep paralysis can be a very frightening experience for some people, and a clear understanding of what actually causes it would have great implications for people who suffer from it," said Baland Jalal, a neuroscientist at the University of California, San Diego.

Researchers say that sleep paralysis happens when a person awakens during a stage of sleep known as rapid eye movement (REM). People in this stage of sleep are usually dreaming, but their muscles are nearly paralyzed, which might be an evolutionary adaptation that keeps people from acting out their dreams.

It is harder to explain why a subset of people who experience sleep paralysis feel a menacing figure in their room or pressing on their chests.

One possible explanation could be that the hallucination is the brain's way of clearing out confusion, when there's a disturbance in the brain region that holds a neural map of the body or the "self," according to a recent article that Jalal and his colleague Vilayanur Ramachandran, of UC San Diego, published in the journal Medical Hypotheses.

"Perhaps, in part of the brain, there's a genetically hardwired image of the body — a template," Jalal told Live Science. Previous studies have suggested that such a region may be a part of the parietal lobes, which are situated in the top-middle part of the brain.

It is possible that during sleep paralysis, the parietal lobes monitor the neurons in the brain that are firing commands to move, but aren't detecting any actual movement in the limbs, which are temporarily paralyzed. This may lead to a disturbance in how the brain builds a sense of the body image, Jalal said. The appearance of a bedroom intruder could result when the brain tries to projectthe person's own body image onto a hallucinated figure, he said.

This idea, though intriguing, would be very difficult to test, Jalal said. One way to gather evidence showing whether this is what is happening inside the brain during sleep paralysis would be to test people who have different body images. For example, if this idea is true, people who are missing a limb might hallucinate figures who are missing the same limb, Jalal said. Still, people with such different body images are likely a small subset of the population, and it would be difficult to conduct such an experiment, he said.

It's also possible that people's differing experiences of sleep paralysis are due to differences in their cultural beliefs. Previous research has suggested that certain ideas found in people's cultures could shape how they experience certain phenomena, Jalal said.

For example, in a 2013 study published in the journal Cultural, Medicine, and Psychiatry, Jalal and his colleague Devon Hinton, of Harvard Medical School, looked at the rates of sleep paralysis, and the amount of stress that people felt because of the episodes, among people of two different societies: Egypt and Denmark. They found that, compared to study participants in Denmark, the Egyptians experienced sleep paralysis more frequently, and had more prolonged episodes that were accompanied with a greater fear of dying from the experience.

"These are two very different cultures; Egypt is very religious, whereas Denmark is one of the most atheist countries in the world," Jalal said.

Most of the Danish participants said they thought sleep paralysis was caused by physiological factors, brain malfunctioning or sleeping the wrong way, whereas the Egyptians were more likely to believe that sleep paralysis is caused by the supernatural.

In another survey, about half of the Egyptian participants from that study said they thought their sleep paralysis was inflicted by a jinn, a ghostlike, menacing creature from Islamic mythology, according to the study, published in the journal Transcultural Psychiatry in 2014.

Jalal and his colleagues concluded that people with such supernatural beliefs tend to experience more fear during sleep paralysis, as well as longer episodes of it. It is even possible that the fear actually contributes to an increase in the person's severe episodes of sleep paralysis, and vice versa, Jalal said.

Read more at Discovery News

Why People Believed Boy's 'Visit to Heaven' Story

A boy who survived a serious car accident and who later wrote an inspiring, best-selling book about meeting angels and God during his near-death experience has now admitted he made it all up.

There are dozens of people who have claimed to visit heaven (or, less often, hell) during near-death experiences.

The best-selling 2010 book “The Boy Who Came Back From Heaven” tells the story of one young boy’s near-death experience: “In 2004 Kevin Malarkey and his six-year-old son, Alex, suffered a terrible car wreck. The impact from the crash paralyzed Alex, and it seemed impossible that he could survive.

“When Alex awoke from a coma two months later, he had an incredible story to share. Of events at the accident scene and in the hospital while he was unconscious… Of the angels who took him through the gates of Heaven itself.”

It was one of two bestselling books about young boys’ experiences in heaven that came out that year; the other, Colton Burpo’s “Heaven is For Real,” was made into a 2014 film.

Colton Burpo’s experiences in heaven may or may not be for real, but Alex Malarkey admits that his is not. The website PulpitandPen.org noted that the book’s publisher “Lifeway has been selling ‘The Boy Who Came Back From Heaven’ for many years now. It is part of the trifecta of books on ‘heavenly tourism’ that Lifeway has sold and has promoted, along with ’90 Minutes in Heaven’ and ‘Heaven is for Real.’

The co-author of ‘The Boy Who Came Back From Heaven’ — the boy himself — has written an open letter to Lifeway and admonished them for not holding to the sufficiency of Scripture, and has recanted his tale.”

Malarkey’s statement read in part, “Please forgive the brevity, but because of my limitations I have to keep this short. I did not die. I did not go to Heaven. I said I went to heaven because I thought it would get me attention. When I made the claims that I did, I had never read the Bible. People have profited from lies, and continue to. They should read the Bible, which is enough. The Bible is the only source of truth. Anything written by man cannot be infallible.”

Propheting from Heaven

Of course the beauty of books about heaven, and there are many of them, some written by people who, like Malarkey, survived accidents and others by claimed psychics such as Sylvia Browne, is that nothing you write can be disproven. If a person claims to have had some personal experience with the unproven and unexplained (whether God or ghosts) we must simply take them at their word absent any compelling corroborating evidence.

Part of the reason that Malarkey’s story was so widely believed and accepted among its Christian audience is that it reinforced their existing narratives and beliefs. If he had described heaven as a place that smells like melted cheddar cheese and was populated by winged elephants singing Britney Spears songs, his experiences, however sincerely conveyed, would have been dismissed as drug-induced hallucinations or the product of a fertile imagination.

Though that may or not be any more accurate than stereotyped visions of winged people in robes walking among clouds, by sticking closely to a widely-accepted Christian interpretation of Heaven, God, and demons, Malarkey assured that his story would meet his audience’s expectations and be popular.

Many of these accounts, including Malarkey’s, involve near-death experiences (NDEs) following trauma. However scientists have cast doubt on the reality of many NDEs.

A 2001 article published in “Trends in Cognitive Sciences” by neuroscientist Dean Mobbs, of the University of Cambridge’s Medical Research Council Cognition and Brain Sciences Unit, and Caroline Watt, of the University of Edinburgh, found that “contrary to popular belief, research suggests that there is nothing paranormal about these experiences. Instead, near-death experiences are the manifestation of normal brain function gone awry, during a traumatic, and sometimes harmless, event.”

Mobbs and Watt noted that many classic NDE symptoms are actually reported by people who were never in danger of dying in the first place.

According to “The Washington Post” the book’s publisher, Tyndale House / Lifeway, has announced that it will stop selling the book and issued a statement reading in part, “We are saddened to learn that Alex Malarkey, co-author of ‘The Boy Who Came Back from Heaven,’ is now saying that he made up the story of dying and going to heaven. Given this information, we are taking the book out of print.”

Of course the book has already made millions of dollars for the publisher over the past five years, so removing it from print will not be a financial hardship.

Read more at Discovery News

Preserved fossil represents oldest record of parental care in group of prehistoric reptiles

New research details how a preserved fossil found in China could be the oldest record of post-natal parental care from the Middle Jurassic.

The specimen, found by a farmer in China, is of an apparent family group with an adult, surrounded by six juveniles of the same species. Given that the smaller individuals are of similar sizes, the group interpreted this as indicating an adult with its offspring, apparently from the same clutch.

A fossil specimen discovered by a farmer in China represents the oldest record of post-natal parental care, dating back to the Middle Jurassic.

The tendency for adults to care for their offspring beyond birth is a key feature of the reproductive biology of living archosaurs -- birds and crocodilians -- with the latter protecting their young from potential predators and birds, not only providing protection but also provision of food.

This behaviour seems to have evolved numerous times in vertebrates, with evidence of a long evolutionary history in diapsids -- a group of amniotes which developed holes in each side of the skull about 300 million years ago and from which all existing lizards, snakes and birds are descended

However, unequivocal evidence of post-natal parental care is extremely rare in the fossil record and is only reported for two types of dinosaurs and varanopid 'pelycosaurs' -- a reptile which resembled a monitor lizard.

A new study by the Institute of Geology, Chinese Academy of Geological Sciences, Beijing; the University of Lincoln, UK; and Hokkaido University, Japan, presents new evidence of post-natal parental care in Philydrosauras, a choristodere from the Yixian Formation of western Liaoning Province, China. Choristoderes are a group of relatively small aquatic and semi-aquatic diapsid reptiles which emerged in the Middle Jurassic Period more than 160 million years ago.

The team reviewed the fossil record of reproduction in this group using exceptionally preserved skeletons of the aquatic choristoderan Philydrosauras. The specimen was donated to the Jinzhou Paleontological Museum in Jinzhou City four years ago by a local farmer who discovered the skeleton.

The skeletons are of an apparent family group with an adult, surrounded by six juveniles of the same species. Given that the smaller individuals are of similar sizes, the group interpreted this as indicating an adult with its offspring, apparently from the same clutch.

Read more at Science Daily

Voyage from Earth's crust to its mantle and back again

Uranium isotopes leave a distinct 'fingerprint' in the sources of volcanic rocks, making it possible to gauge their age and origin. Geologists have gained a new understanding of how Earth's crust is recycled back into its interior based on these uranium isotopes.

From the beginning of time, uranium has been part of Earth and, thanks to its long-lived radioactivity, it has proven ideal to date geological processes and deduce Earth's evolution. Natural uranium consists of two long-lived isotopes uranium-238 and the lighter uranium-235. A new study of the global cycle of these uranium isotopes brings additional perspectives to the debate on how Earth has changed over billions of years as revealed in a recently published study in the journal Nature.

From early Earth history, the continental crust (Earth's thick solid outer skin that we live on) has accumulated mass from the underlying hot mantle. Most of the newly formed crust, however, is lost again. At mid-ocean ridges at the bottom ocean, where plates drift apart, new oceanic crust is constantly produced as basaltic rocks when hot volcanic lava emerges from the mantle and solidifies. The oceanic crust moves away from the mid-ocean-ridges and ultimately gets transported back into the underlying mantle through "subduction" at ocean trenches.

Uranium is enriched in the rocks of the continental crust; however, at Earth's surface, different environments over time have influenced its mobility. In an oxygen-free atmosphere, as prevailed on early Earth, uranium stayed immobile in rocks as tetravalent uranium (IV). Only after atmospheric oxygen was formed did uranium become oxidised to its mobile hexavalent uranium (VI). This more mobile uranium may then be released during the weathering and break-down of rocks and transported to the oceans in aqueous form. As the cooling oceanic crust moves away from the mid-ocean-ridges in the oceans, seawater eventually percolates through cracks in its rock and in the process uranium gets incorporated into the oceanic crust, in a similar way that a sponge takes up water.

"The radioactive nature of uranium isotopes has long been key in reconstructing early Earth history, but we now see that they also have another story to tell" explains Morten Andersen, a geochemist in the Department of Earth Sciences at ETH Zurich.

Uranium isotopes form specific signatures

For this work, conducted at the University of Bristol including Morten Andersen (now Earth Science, ETH Zurich) along with researchers from the Durham (UK), Wyoming and Rhode Island (US), used the 'fingerprint' carried in the ratio of the two uranium isotopes.

The specific "fingerprint" derived from the ratio of the uranium isotopes, relates to uranium oxidation processes at Earth's surface. In particular, the researchers found that a higher ratio of uranium-238 to uranium-235 is incorporated into the modern oceanic crust, when compared to the uranium isotope signature found in meteorites. The meteorites represent Earth's "building blocks" and, thus, yield the original uranium isotope composition of Earth as a whole, and also the undisturbed mantle. This uranium isotope "fingerprint" of the altered oceanic crust provides a way to trace uranium that has moved from the surface and back into Earth's interior through subduction.

In order to examine the uranium cycle (and the rock cycle), the researchers analysed mid-ocean ridge basalts (MORBs), the hot volcanic lava that is produced from the upper and well-mixed part of the mantle. The ratio of the uranium isotopes in MORBs can be compared with those found in ocean island basalts in places such as Hawaii and the Canary Islands. These islands are so-called "hot-spots" with lava formed from hot mantle plumes that up-well beneath the oceanic crust. Compared to the MORB mantle, the island basalts are made up of material transported to the surface from a much deeper, less well-mixed, mantle sources.

Heavy uranium from surface to the deep

The isotope ratios for uranium-238 to uranium-235 are significantly greater for MORBs than for ocean island basalts. The ratios are also higher than that found in meteorites. This suggests that the MORBs contain a "fingerprint" of the uranium from the oceanic crust, drawn down from the surface and into the upper part of Earth's mantle through subduction, according to Andersen.

Through convection -- slow movements of material in the upper mantle -- the material was eventually mixed around and carried to the area of the mid-ocean ridges and transported back to the surface in the lavas that make up MORBs.

In contrast, the island basalts' ratios of uranium-238 to uranium-235 correspond to those of the meteorites used in the study and showed that these rocks could not have the same mantle source as the MORBs. The researchers explain that ocean island lavas comes from a deeper, less mixed, mantle source and therefore any uranium added from the surface originates from a much earlier time in Earth's history, when the surface environment was very different from today.

Study co-author Heye Freymuth of the University of Bristol explains: "Although uranium was incorporated into the oceanic crust since the initial rise in atmospheric oxygen about 2.4 billion years ago, the ocean crust did not incorporate higher amounts of uranium-238 as the oceans did not yet have adequate supplies of oxygen."

Only during the second marked increase in atmospheric oxygen content 600 million years ago did the deep ocean become fully oxidised, which allowed the oceanic crust to gain the "fingerprint" of high uranium-238. So, despite the oceanic crust having been transported into Earth's mantle for a long time, the uranium isotope ratio of the subducted oceanic crust first differed from Earth's mantle only after the full oxidation of the oceans.

"An important result of this study is how changing conditions on Earth's surface and the increase of oxygen in the atmosphere influenced the composition of deep Earth. Our results suggest that due to changes over the past 600 million years, uranium was mobilised from the surface, transported into Earth's interior and distributed within the mantle," says Andersen.

Read more at Science Daily

Tantalizing Detail Seen on Mysterious Dwarf Planet

As NASA’s trailblazing Dawn mission approaches dwarf planet Ceres, a new series of images beamed back show tantalizing detail in the mysterious world’s surface.

The robotic probe will, in March, become the first ever mission to orbit two solar system bodies. After leaving orbit around massive asteroid Vesta in 2012, Dawn has steadily made its way to its second massive target in the asteroid belt, a region sandwiched between the orbits of Mars and Jupiter.

When Dawn arrives at Ceres, this will be our first ever visit to the enigmatic world that has long-fascinated astronomers and planetary scientists alike.

“We know so much about the solar system and yet so little about dwarf planet Ceres. Now, Dawn is ready to change that,” said Marc Rayman, Dawn’s chief engineer and mission director, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

These new observations of Ceres are from only 238,000 miles (383,000 kilometers) away, and appear to show craters and geological variations. Although it is fascinating to see the 590 mile- (950 kilometer-) wide dwarf planet through Dawn’s eye, this 27-pixel-wide view is still only 80 percent the resolution of Hubble’s best observations of Ceres acquired in 2003 and 2004. But this will soon change — over the coming weeks we’ll see Ceres slowly snap into view, surpassing even the best resolution of any space telescope.

“The team is very excited to examine the surface of Ceres in never-before-seen detail,” said Chris Russell, principal investigator for the Dawn mission, at the University of California, Los Angeles. “We look forward to the surprises this mysterious world may bring.”

Previous studies of Ceres have provided evidence that Ceres was a protoplanet that evolved amongst the debris of the asteroid belt. Observations in early 2014 even detected water vapor surrounding Ceres, which hints of a subsurface ocean beneath an icy crust — not too dissimilar to Jupiter’s moon Europa and Saturn’s moon Enceladus. Of course, any detection of water on or near another planet brings speculation of life — something astrobiologists will be excited to test on the solar system’s innermost dwarf planet.

Read more at Discovery News

Chimps 'Talk' About Their Favorite Foods, Trees

Researchers eavesdropping on wild chimpanzees determined that the primates communicate about at least two things: their favorite yummy fruits, and the trees where these fruits can be found.

Of particular interest to the chimps is the size of trees bearing the fruits that they relish most, such that the chimps yell out that information, according to a new study published in the journal Animal Behaviour.

The study is the first to find that information about tree size and available fruit amounts are included in chimp calls, in addition to assessments about food quality.

"Chimpanzees definitely have a very complex communication system that includes a variety of vocalizations, but also facial expressions and gestures," project leader Ammie Kalan of the Max Planck Institute for Evolutionary Anthropology told Discovery News.

"How much it resembles human language is still a matter of debate," she added, "but at the very least, research shows that chimpanzees use vocalizations in a sophisticated manner, taking into account their social and environmental surroundings."

Kalan and colleagues Roger Mundry and Christophe Boesch spent over 750 hours observing chimps and analyzing their food calls in the Ivory Coast's Taï Forest. The Wild Chimpanzee Foundation in West Africa is working hard to try and protect this population of chimps, which is one of the last wild populations of our primate cousins.

The researchers found that higher pitched calls were produced when the chimps encountered fruits from Nauclea trees. Smaller trees elicited still higher pitched calls, while calls associated with bigger trees with more fruit were lower in pitch.

In short, the chimps seem to "talk" a lot about Nauclea fruits!

"I never tried these fruits myself, but they do smell very good in the forest," Kalan said. "They are also quite big and easy to ingest, and we also know that they have a high energy content, which is important for wild animals."

A hallmark of human language is that vocalizations are “functionally referential.” Kalan and her team explained that this means the calls specifically refer to a particular individual, place, thing or happening, and that they must generate an appropriate response from those who hear the calls.

In this case, whenever the chimps called out after they found a large Nauclea fruit tree, their relatives would come running. The “dinner bell” effect is itself of interest, since it demonstrates how generous these primates can be.

"Chimpanzees are incredibly social beings, and sharing food is just one way of many that individual chimpanzees can solidify relationships within their group," Kalan said, adding that chimps travel in independent parties throughout the day, and almost never with their whole group at once.

She continued, "Calling for one another at a food tree is one way that they can attract other chimpanzees in order to meet up with members of their group that they have not seen for a while."

Klaus Zuberbühler, a professor in the School of Psychology and Neuroscience at the University of St. Andrews, also studies primate communication. Zuberbühler told Discovery News, "What the authors have shown is that (chimp) call structure changes, not only in response to the food type, which was already known before, but also in relation to the size of the tree, a new finding."

Read more at Discovery News

Machines teach astronomers about stars

Astronomers are enlisting the help of machines to sort through thousands of stars in our galaxy and learn their sizes, compositions and other basic traits.

The research is part of the growing field of machine learning, in which computers learn from large data sets, finding patterns that humans might not otherwise see. Machine learning is in everything from media-streaming services that predict what you want to watch, to the post office, where computers automatically read handwritten addresses and direct mail to the correct zip codes.

Now astronomers are turning to machines to help them identify basic properties of stars based on sky survey images. Normally, these kinds of details require a spectrum, which is a detailed sifting of the starlight into different wavelengths. But with machine learning, computer algorithms can quickly flip through available stacks of images, identifying patterns that reveal a star's properties. The technique has the potential to gather information on billions of stars in a relatively short time and with less expense.

"It's like video-streaming services not only predicting what you would like to watch in the future, but also your current age, based on your viewing preferences," said Adam Miller of NASA's Jet Propulsion Laboratory in Pasadena, California, lead author of a new report on the findings appearing in the Astrophysical Journal. "We are predicting fundamental properties of the stars."

Miller presented the results today at the annual American Astronomical Society meeting in Seattle.

Machine learning has been applied to the cosmos before; what makes this latest effort unique is that it is the first to predict specific traits of stars, such as size and metal content, using images of those stars taken over time. These traits are essential to learning about when a star was born, and how it has changed since that time.

"With more information about the different kinds of stars in our Milky Way galaxy, we can better map the galaxy's structure and history," said Miller.

Every night, telescopes around the world obtain thousands of images of the sky. The flood of new data is only expected to rise with upcoming wide-field surveys like the Large Synoptic Survey Telescope (LSST), a National Science Foundation and Department of Energy project that will be based in Chile. That survey will image the entire visible sky every few nights, gathering data on billions of stars and how some of those stars change in brightness over time. NASA's Kepler mission has already captured the same kind of time-varying data on hundreds of thousands of stars.

Humans alone can't easily make sense of all this data. That is where machines, or in this case, computers using specialized algorithms, can help out.

But before the machines can learn, they first need a "training period." Miller and his colleagues started with 9,000 stars as their training set. They obtained spectra for these stars, which revealed several of their basic properties: sizes, temperatures and the amount of heavy elements, such as iron. The varying brightness of the stars had also been recorded by the Sloan Digital Sky Survey, producing plots called light curves. By feeding the computer both sets of data, it could then make associations between the star properties and the light curves.

Once the training phase was over, the computer was able to make predictions on its own about other stars by only analyzing light-curves.

"We can discover and classify new types of stars without the need for spectra, which are expensive and time-consuming to obtain," said Miller.

The technique essentially works in the same way as email spam filters. The spam filters are programmed to identify key words associated with junk mail, and then remove the unwanted emails containing those words. With time, a user continues to "teach" the filtering program more key words, and the program becomes better at filtering spam. The machine learning program used by Miller and collaborators likewise becomes better at accurately predicting properties of the stars with additional training from the astronomers.

Read more at Science Daily

Mysterious Shipwreck Found in Lake Michigan

Beneath the cold waves of Lake Michigan rests an aging shipwreck, its wooden planks encrusted with brown-and-gray zebra mussels, that may be the remnants of a 17th-century ship called the Griffin, two Michigan-based treasure hunters say.

French explorer René-Robert Cavelier, Sieur de La Salle built the Griffin in 1679, but it was lost in Lake Michigan the same year.

In 2011, Michigan-based treasure hunters Kevin Dykstra and Frederick Monroe found a shipwreck as they were searching for the $2 million in gold that, according to local legend, fell from a ferry crossing Lake Michigan in the 1800s, they told WZZM, a western Michigan news station.

Their sonar caught a mass below, and Dykstra dove into the water to take video.

"I didn't go down there with the expectation of seeing a shipwreck — I can tell you that," Dykstra told Live Science. When he and Monroe later reviewed the video, they realized it might be the Griffin.

But other experts aren't convinced that the wreck is the Griffin. Rather, it may be the remnants of a tugboat that was scrapped after "steam engines became more economical to operate," said Brendon Baillod, a Great Lakes historian who has written scholarly papers on the Griffin.

The wreck's discoverers agree that more evidence is needed.

State archaeologists reviewed the footage, and "They've been very diligent to say, 'This is really interesting; these are some neat pictures,'" Dykstra said. "Can we call this the Griffin? Certainly not — not without a lot more information — but these are very compelling."

Le Griffon

La Salle sailed the Griffon through the Great Lakes and crossed into Lake Michigan in an effort to reach the mouth of the Mississippi River, Baillod said. But the explorer ran out of money, so he disembarked with the other expedition leaders, leaving the ship and its crew to pay off his debts with furs. La Salle never saw the Griffin again.

La Salle returned to the area in 1682, to try again to locate the Mississippi's mouth. But members of the Potawatomi tribe brought pieces of the ship to the explorer, including some moldy beaver furs and a pair of sailor's britches, said Baillod, who translated La Salle's journal from French to English.

The Native Americans told La Salle the crew planned to sail toward the Straits of Mackinac in stormy weather.

"The Indians told the captain not to sail out, to wait the storm out, but he wouldn't listen to them," Baillod said. The captain lost control of the ship as strong winds blew it away from shore, southward, toward islands in the distance.

"They lost the ship from sight," Baillod said, "and that's the last anybody has ever seen the Griffin."

Shipwreck spotted

About 30 adventurers have claimed to have found the Griffin, usually by happenstance, Baillod said.

"They're looking for something else, they find an old ship and they've heard of the Griffin, so they pronounce it the Griffin," Baillod said.

Moreover, Baillod said he hasn't heard of anyone looking for the Griffin near the Beaver Island archipelago, which is likely the area mentioned in La Salle's journal, Baillod said.

But the latest finding, made popular again by Wreck Diving Magazine in its latest issue, holds a number of clues about the ship's past.

"There was no rudder on the boat," Dykstra said. "That was kind of telling to us that the ship probably weathered a storm; otherwise, there would probably be a rudder on it."

They also found a part of the ship that they said could be a mussel-covered griffin, the mythical beast carved onto the ship's bow.

On a subsequent dive, Dykstra took a magnet with him to help determine the metal composition of the ship. Unexpectedly, a nail attached itself to the magnet, and the treasure hunters only discovered it later, once they were above water.

"When we had it looked at, they [the archaeologists] could tell that the nail was very old," Dykstra said. "It was a hand-forged nail, which helps date it back to that time period, we feel."

The state of Michigan has rules stipulating that artifacts found on state land, including the land at the bottom of the Great Lakes, are state property. The two men did not bring up the nail on purpose, and they plan to return it to the state, said Dean Anderson, the state archaeologist for Michigan.

About 1,500 shipwrecks have been found on the bottom of Lake Michigan, Anderson said, and it's unclear whether this one is the Griffin.

"It's very difficult to access a wreck based on photo and film footage," Anderson said. If the state underwater archaeologist were to look at the wreck, he would look for artifacts that could be dated, such as ceramics or glass.

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