Cas Liber

A hypsilophodon skeletal cast at the Melbourne Museum. Ancient crocociles noshed on young hypsilophodon dinosaurs, researchers have found.

By Charles Choi
LiveScience

Crocodile-like beasts may have nibbled on young dinosaurs some 75 million years ago, according to scientists who analyzed bite marks on dinosaur bones.

The findings suggest the rivalry between the reptiles started early in life, the researchers say.

Bites from living crocodylians such as alligators and crocodiles are often seen on the bones of their prey and scavenged bodies. Scientists can use these to identify bite marks on fossils from crocodyliforms, the reptiles to which modern crocodylians belong.

Research investigating crocodyliforms from the age of dinosaurs has often focused on the largest such reptiles feeding on equally giant dinosaurs. Now, paleontologists have direct evidence of a small crocodyliform biting juvenile dinosaurs.

Scientists unearthed these fossils in the Grand Staircase-Escalante National Monument in southern Utah.

Boyd CA, Drumheller SK, Gates TA (2013) Crocodyliform Feeding Traces on Juvenile Ornithischian Dinosaurs from the Upper Cretace

CT scans show puncture marks and embedded croc teeth in a juvenile dinosaur bone.

"This area is very hot and arid in the summer and cold in the winter," said researcher Clint Boyd, a vertebrate paleontologist at the South Dakota School of Mines and Technology. "Most of the area is dominated by massive, cliff-forming rock outcrops."

Back when the reptiles were alive, their environment was warm and wet, dominated by rivers and floodplains and lush with bushes and trees. Dinosaurs in the area included duck-billed hadrosaurs, horned ceratopsians such as Triceratops and predatory relatives of T. rex. The area also holds an especially diverse assembly of crocodyliforms, including the gigantic alligatoroid Deinosuchus riograndensis. [Paleo-Art: Stunning Illustrations of Dinosaurs]

The researchers unearthed 75-million-year-old fossils of at least three members of a kind of small, two-legged herbivorous dinosaur known as a hypsilophodontid. On the right thighbone of one, the researchers found a conical tooth embedded that was just 2.5 millimeters wide (a little less than one-tenth of an inch), and similarly tiny puncture marks were seen on a left shoulder bone.

"I was very surprised to find such clear feeding traces on such small bones," Boyd told LiveScience. "It shows the importance of carefully evaluating all the fossils collected from an area, and not assuming that some fossils won't be important just because they are very small or not completely preserved."

It remains uncertain how large the crocodyliform that made the marks was. However, the dinosaurs in question probably weighed about 28 to 46 pounds (13 to 21 kilograms); and living crocodylians 3 to 6 feet (1 to 1.8 meters) long are known to take down prey that big.

"Usually people tend to focus on the dangers that big, adult dinosaurs were having to deal with, but this study shows that even though dinosaurs were the dominant animals during the Cretaceous, they still had to worry about predators as soon as they were born," Boyd said.

The researchers will continue to study fossils from many time periods to look for additional traces of crocodyliform feeding, such as at an approximately 33-million-year-old locality in Badlands National Park in South Dakota.

Boyd and his colleagues Stephanie Drumheller and Terry Gates detailed their findings online Wednesday in the journal PLOS ONE.

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Douglas Blackiston

Researchers grafted the tails of blind tadpoles of the African frog with eye tissue, which gave the tadpoles sight.

By Charles Choi, LiveScience contributor

Eyes hooked up to the tail can help blinded tadpoles see, researchers say.

These findings could help guide therapies involving natural or artificial implants, scientists added.

A major roadblock when it comes to treating blindness and other sensory disorders is how much remains unknown about the nervous system and its ability to adapt to change. To learn more about the relationship between the body and the brain, researchers wanted to see how capable the brain was of interpreting sensory data from abnormal "ectopic" locations from which it normally does not receive  signals.

Eye on the tail
Scientists experimented with 134 tadpoles of the African clawed frog Xenopus laevis, a common lab animal. They painstakingly grafted new eyes onto places such as their torsos and tails and then surgically removed their original eyes. [See Images of the Odd-Eyed Tadpoles]

"We do a lot of work to understand regenerative biology, and that entails experiments that change the body," researcher Michael Levin, a developmental biologist at Tufts University, told LiveScience. "We have four-headed worms, six-legged frogs, and many other unusual creatures here as part of our work on bioelectricity and organ regeneration."

These experimental tadpoles then received a vision test the researchers first refined on normal tadpoles. The tadpoles were placed in a circular arena half illuminated with red light and half with blue light, with software regularly switching what color light the areas received. When tadpoles entered places lit by red light, they received a tiny electric zap. A motion-tracking camera kept tabs on where the tadpoles were.

Remarkably, the scientists found that six tadpoles that had eyes implanted in their tails could apparently see, choosing to remain in the safer blue-light areas.

"The brain is not wired to find an eye on the tail, since it's never happened before and thus is not something the brain has evolved specifically to deal with, and yet it can recognize this patch of tissue as providing valuable visual information," Levin said.

"These findings suggest that the brain has remarkable plasticity and may actually take a survey of its body configuration to make use of different body arrangements," Levin added. "If it were not the case, then every time a mutation produced an improvement in body plan — a large significant change in anatomy — the animal would die and the beneficial mutation would be lost."

Rather, when a mutation makes a change in the body plan of an embryo, the brain-body programs that tell an eye to see and a hand to grasp, for instance, "don't suddenly become useless," Levin said. "The brain can map its activity onto a wide range of configurations of the body. This modularity makes it much easier for complex new body features to evolve."

Douglas Blackiston

Here, a close-up of the eye growing out of the tail of a tadpole.

Augmentation technology
The transplanted eyes came from tadpole donors genetically modified to generate a red fluorescent protein. As such, the researchers could see under a microscope whether these eyes sent red nerves outward in the body. Half the recipient tadpoles had no such nerves grow, while about a quarter had nerves projecting toward the gut and the other quarter had nerves extending toward their spine.

The six tadpoles that could see well all had nerves plugged into their spine, which makes sense — their eyes apparently linked with their central nervous system.

"This has implications not only for regenerative medicine — replacing damaged sensory and motor organs — but also for augmentation technology," Levin said. "Perhaps you'd like some more eyes, maybe ones that see in infrared?" [Bionic Humans: Top 10 Technologies]

One question Levin and his colleagues often get asked "is whether the tadpoles are experiencing sight from these ectopic eyes like they do from normal eyes," Levin said. "We have no idea what a tadpole is experiencing. This is a philosophical question that is not immediately tractable.

"Another thing people sometimes assume is that this capability is only for tadpoles or 'lower' animals," Levin said. "In fact, this kind of thing probably works in humans also, as evidenced by related studies over the last few years. Brain plasticity is a fundamental aspect of the function of the nervous system and its interface to the body."

The researchers seek to figure out three other aspects: which brain regions are processing the sensory data, how many extra eyes a frog brain can handle, and how the brain knows that this piece of tissue on the tail is providing visual data, and not simply indicating an infection, injury or other sense like smell, Levin said.

Levin and his colleague Douglas Blackiston detailed their findings online Feb. 27 in the Journal of Experimental Biology.

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Yie Jang (Yunnan University)

Scientists have unearthed a stunningly preserved arthropod, called a fuxhianhuiid, in a flipped position that reveals its feeding limbs and nervous system.

By Tia Ghose
LiveScience

Scientists have unearthed extraordinarily preserved fossils of a 520-million-year-old sea creature, one of the earliest animal fossils ever found, according to a new study.

The fossilized animal, an arthropod called a fuxhianhuiid, has primitive limbs under its head, as well as the earliest example of a nervous system that extended past the head. The primitive creature may have used the limbs to push food into its mouth as it crept across the seafloor. The limbs may shed light on the evolutionary history of arthropods, which include crustaceans and insects.

"Since biologists rely heavily on organization of head appendages to classify arthropod groups, such as insects and spiders, our study provides a crucial reference point for reconstructing the evolutionary history and relationships of the most diverse and abundant animals on Earth," said study co-author Javier Ortega-Hernández, an earth scientist at the University of Cambridge, in a statement. "This is as early as we can currently see into arthropod limb development."

The findings were published Wednesday in the journal Nature.

Primordial animal
The fuxhianhuiid lived nearly 50 million years before animals first emerged from the sea onto land, during the early part of the Cambrian explosion, when simple multicellular organisms rapidly evolved into complex sea life. [See Images of the Wacky Cambrian Creatures ]

While paleontologists have unearthed previous examples of a fuxhianhuiid before, the fossils were all found in the head-down position, with their delicate internal organs obscured by a large carapace or shell.

However, when Ortega-Hernández and his colleagues began excavating in a fossil-rich region of southwest China around Kunming called Xiaoshiba, they unearthed several specimens of fuxhianhuiid where the bodies had been flipped before fossilization. All told, the team unearthed an amazingly preserved arthropod, as well as eight additional specimens.

These primeval creatures probably spent most of their days crawling across the seabed trawling for food and may have also been able to swim short distances. The sea creatures, some of the earliest arthropods or jointed animals, probably evolved from worms with legs.

The discovery sheds light on how some of the earliest ancestors of today's animals may have evolved.

"These fossils are our best window to see the most primitive state of animals as we know them – including us," Ortega-Hernández said in a statement. "Before that there is no clear indication in the fossil record of whether something was an animal or a plant – but we are still filling in the details, of which this is an important one."

Follow Tia Ghose on Twitter @tiaghose or LiveScience @livescience. We're also on Facebook and Google+. 

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Ray Troll

This is a re-creation of a Helicoprion, which lived 270 million years ago and is the only animal ever with a complete 360-degree spiral of teeth.

By Jennifer Viegas
Discovery

The world’s only animal, past or present, with a complete 360-degree spiral of teeth was Helicoprion, which sliced into prey like a buzzsaw.

This sharklike fish, which lived 270 million years ago, is described in the latest issue of Biology Letters. It had one of the most unusual mouths and sets of teeth in the animal kingdom.

"When the animal closed its mouth on prey, the spiral of sharp teeth rotated backwards, like a circular saw, and slashed through the meat,” lead author Leif Tapanila, an associate professor in the Department of Geosciences at Idaho State University, told Discovery News.

PHOTOS: Living Fossils, Animals From Another Time

Tapanila is also the research curator and head of the Earth Sciences Division at the Idaho Museum of Natural History. For the study, he and his colleagues took the first ever 3-D images of Helicoprion remains.

Scientists have puzzled over this animal for more than a century, given its highly unusual "tooth whorl.” The new research sheds light on what this prehistoric marine species looked like, what its ancestry was and how it behaved.

"Helicoprion looked a lot like a big-bodied modern shark, but it had a very unusual mouth,” Tapanila said. "An arc of 15 to 18 serrated teeth were exposed in the center of its lower jaw, and it had no protruding teeth in the upper jaw.”

Ray Troll

Leif Tapanila, an associate professor in the Department of Geosciences at Idaho State University, with the Helicoprion fossil.

The buzz saw-looking tooth whorl had two functions, the researchers determined. The outermost part anchored the teeth for biting, while the rest of the inner spiral was designed to house the old and previously used teeth from when the animal was younger.

The scientists did not see much wear, tear and breakage, so they suspect Helicoprion primarily sliced into squid or other ancient relatively soft and somewhat chewy sea life. Aside from squid and their early relatives, armored and cartilaginous fish lived in Helicoprion’s ecosystem, along with brachiopods, bivalves and snails. "Cartilaginous” refers to fish made up of cartilage, a firm yet flexible connective tissue.

While Helicoprion looked and acted like a shark, the researchers determined that it’s at the base of the family tree that today includes chimaera (aka "ghost sharks”) and ratfish. Ghost sharks are not technically sharks, but they look and act a lot like them.

Tapanila explained that cartilaginous fish are divided into two main categories: sharks and rays on one side, ratfish and chimaera on the other. They are all marine predators.

NEWS: Shark-Headed Human Ancestor Swam With Fishes

No living land or sea animal directly resembles Helicoprion -- especially it’s buzz-saw tooth whorl.

"It was really an improbable animal, and maybe one of the best examples of a successful ‘Hopeful Monster,’” Tapanila said, explaining that this refers to evolutionary processes that can result in very unusual body types, with most doomed to failure.

While Helicoprion eventually went extinct, it used to have a nearly global distribution and existed over a period of 10 million years or more, proving that even some eccentric body designs can be successful if they meet the particular needs influenced by the animal’s environment, food sources and more.

John Long, a professor of paleontology at Flinders University, told Discovery News that he fully supports the new findings about Helicoprion and its kin.

"This study ends a century old mystery about this iconic fossil (species) and highlights the unexpected diverse body form that holocephalans occupied,” Long said.

Tapanila and his team would love to find a fossilized prey animal in the mouth of such a prehistoric shark-like animal, to better determine which exact species they were hunting and eating. Given that they lived even before the dinosaurs, Tapanila isn’t "holding his breath” for such a rare find.

David A. Aguilar (CfA)

A planetary nebula surrounds a white dwarf star with a hypothetical habitable planet in orbit.

By Irene Klotz
Discovery

Earth-sized planets that host life should be far easier to find around parent stars that are white dwarfs, the ultimate incarnations of stars like the sun, a new study shows.

Alien worlds could circle dying white dwarf stars, this NBCNews.com report explains.

White dwarfs are the dense stellar cores that remain after a sunlike star runs out of fuel and goes through its expanding, red giant phase, a process that will consume its inner planets. In our solar system, for example, Mercury, Venus and possibly Earth will be destroyed when the sun evolves into a red giant some 4.5 billion years from now.

But the system won't necessarily be doomed.

PICTURES: Exquisite Exoplanetary Art

Outer planets may migrate inward, closer to the star, and new worlds may form. Not all will be in stable orbits, but an Earth-sized world located about 1 million miles away from a host white dwarf star would have a temperature roughly the same as Earth’s. At that distance, the planet could have liquid water on its surface, a condition believed to be necessary for life.

Scientists are developing techniques to scan the atmospheres of planets beyond the solar system for oxygen and other chemical signs of life. It's a laborious and time-consuming process to separating out light passing through a planet’s atmosphere from all the background starlight.

But Earth-sized planets circling white dwarf stars, which are themselves about as big as Earth, make for much bigger needles in extrasolar planet haystacks.

ANALYSIS: Could Dead Stars Support Life? 

Avi Loeb, a theorist at the Harvard-Smithsonian Center for Astrophysics, figures the upcoming James Webb Space Telescope, a successor to the Hubble observatory, would need only about five hours of observing time to look for biomarkers in the atmosphere of a planet circling in a white dwarf’s habitable zone.

“Usually the background star is so much brighter, it’s so much bigger than the planet that absorption (of light) due to the atmosphere is a very small signal that you have to fish out of the much more prominent emission from the background star,” Loeb told Discovery News.

“In the case of the white dwarf, it’s sort of the best of all circumstances, where the object that is blocking the star is of the same size as the star itself. That offers the best prospect for detecting the absorption due to the atmosphere, relative to the background light,” he said.

Like NASA’s planet-hunting Kepler Space Telescope, the technique would only work for white dwarf systems that are aligned relative to the observatory’s line of sight so that orbiting planets pass in front of, or transit, their parent stars.

While the star is eclipsed, some light will pass through the planet’s atmosphere -- if it has one -- and leave telltale chemical fingerprints that can be detected by instruments in a telescope.

“If we happen to be situated so that we can see an eclipse, then the planet would block a substantial fraction of the light from the white dwarf. Then we can basically use the light that is passing through the atmosphere to figure out what the atmosphere is made of,” Loeb said.

VIDEOS: Aliens and Other Space Mysteries

Of key interest would be detections of oxygen, which on Earth is a clear sign of life from photosynthesis by plants.

“The only reason we have oxygen in the atmosphere right now is because of life,” Loeb said. “If you remove life from Earth, then within 1 million years or so, the oxygen will be completely depleted. It will make all kinds of molecules of oxidized metals, for example, and it will be consumed from the atmosphere.”

Scans of exoplanets’ atmospheres also could find water vapor and other potential biomarkers.

While there is not yet any direct evidence of planets circling white dwarfs, astronomers believe they exist. Previous studies have shown that as many as 30 percent of white dwarf stars have heavy elements on their surfaces, presumably from rocky bodies that broke up relatively soon after the white dwarf formed.

PICTURES: Exquisite Exoplanetary Art

A planet could find a stable orbit in white dwarfs’ habitable zone, one that would have it circle its parent star in just 10 hours.

“I’m not saying that we definitely know that such planets are there, but it’s quite plausible that the system after a while cleans itself up and for over a billion years or more, it may have stable Earth-mass planets,” Loeb said.

“It sounds like a reasonable extrapolation for what we’ve seen,” added astronomer Marc Kuchner, with the Exoplanets and Stellar Astrophysics Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md.

“There’s no reason to think you wouldn’t find one now and then," Kuchner told Discovery News.

The research will be published in an upcoming edition of the Monthly Notices of the Royal Astronomical Society and is available online via the arXiv preprint service.

Jim Steenburgh, University of Utah

Erik Steenburgh of Salt Lake City skis deep powder during a lake-effect snowstorm at Alta Ski Area in Utah's Wasatch Range in April 2011. Steenburgh is the son of Jim Steenburgh, a University of Utah atmospheric scientist.

By Andrea Thompson
LiveScience

Those who live around the Great Lakes are very familiar with the snow those bodies of water can bring, a phenomenon called lake-effect snow. But a new study suggests that lakes aren't always the only feature behind the falling flakes.

Nearby mountains can enhance or dampen a lake-effect storm, depending on where they sit in relation to the lake, and they may even be necessary to trigger some lake-effect snowfall, the study finds.

University of Utah researchers explored the role that local topography plays in driving lake-effect snow with computer simulations of a lake-effect storm around Utah's Great Salt Lake, even with the relatively gentle terrain around the lake.

"It is going to help us with weather prediction— helping forecasters recognize that in some lake-effect events, the mountains or hills can play an important role in triggering lake-effect snow bands" over large bodies of water, study author Jim Steenburgh said in a university release.

Mountains' influence
Here's how the lake effect works: A cold air mass moves over a large body of water that is warm in comparison (because more heat has to be released to change the temperature of water than air); the air picks up moisture and heat, then rises. As it does so, the air cools, and the moisture it contains condenses out, forming snow if the air is cold enough.

Jim Steenburgh, University of Utah

This map shows how mountains surrounding Utah's Great Salt Lake interact with the lake to cause some "lake-effect" snowstorms. Air masses from the north-northwest are channeled by mountains north of the lake so they converge above the lake. The air picks up heat and moisture from the lake, so it rises, cools and produces snow as it is funneled into the Salt Lake Valley by surrounding mountains.

It was previously known that lake-effect snow could intensify as it moved up over a mountain, which further cools the air and forces more moisture out over the highlands. But the simulations of lake-effect storms around the Great Salt Lake that Steenburgh and his colleagues ran showed that sometimes the influence of the mountains extended below the high mountain altitudes, triggering snow over lowlands and the lake itself when the mountains were downstream of the body of water. [The World's Weirdest Weather]

In other cases, mountains upstream of the lake dampened the lake-effect snow, because the cold air descending down the side of the mountain warmed and dried before it hit the lake. This resulted in less snow fall than if the mountains weren't present.

The configuration of mountains can also force together cold air masses, making them converge over the lake.

"Most people recognize that mountains get more precipitation than lowlands, because of moist air being lifted over the mountains," Steenburgh said in the release. "Everybody recognizes that it plays a role in lake-effect storms. What we're showing here is a situation where the terrain is complicated. There are multiple mountain barriers, not just one, and they affect the air flow in a way that influences the development of the lake-effect storm over the lake and lowlands, rather than just over the mountains."

Missing from models
This unrecognized ability of the mountains to both dampen and trigger snow could help explain why forecasters have difficulty predicting the occurrence of lake-effect storms and how much snow they will drop on Utah's cities, Steenburgh said. The models currently used don't adequately include the Wasatch Range or the northern mountains along the Nevada-Idaho-Utah border.

Gaining a better idea of the factors influencing lake-effect snow will help forecasters better predict the traffic snarls the weather can cause, as well as the fresh snow it can provide to ski resorts.

"These influences need to be better represented in weather forecast models," Steenburgh told OurAmazingPlanet in an email.

The new study was published Feb. 18 in the American Meteorological Society's journal, Monthly Weather Review.

Reach Andrea Thompson at athompson@techmedianetwork.com and follow her on Twitter @AndreaTOAP and on Pinterest. Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.

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Niklas Liljeback

In the winter, thousands upon thousands of the common roach fish migrate to nearby streams throughout Europe.

By Joseph Castro
LiveScience

From birds to crustaceans, numerous animal species migrate each year to find more food, pleasant weather or the perfect place to breed. But at least one species — a freshwater fish called the common roach — migrates to avoid getting eaten, new research suggests.

Researchers used identifier tags to track the seasonal movements of the common roach (Rutilus rutilus) for four years. These fish live in freshwater lakes throughout Europe and are partially migratory — that is, during winter, up to 80 percent of the fish migrate to nearby streams, while the rest stay put.

"It's a bit of an overwhelming sight to come across these streams in wintertime, and you suddenly realize that there are thousands upon thousands of fish in this restricting area," said lead researcher Christian Skov, a fish ecologist at the Technical University of Denmark.

Cormorant birds (Phalacrocorax carbo) are known to prey on roach living in both lakes and streams. However, 92.5 percent of the tags retrieved from cormorant pellets came from roach that last swam in lakes specifically, the researchers found. Moreover, the longer the fish stayed out of the lakes, the more likely they were to escape becoming bird food, suggesting that the fish reduce their predation risk from the birds by migrating into streams. [The 10 Most Incredible Animal Journeys]

Jes Dolby

Researchers attached passive integrated transponder tags to more than 2,200 roach fish living in two lakes in Denmark. Then they set up antennas (shown here) to pick up signals from the tags.

Lakes vs. streams
The idea that some animals migrate to escape predation isn't new, but evidence for this behavior is hard to come by. In 2010, scientists discovered predation was partially involved in the breeding migrations of Arctic shorebirds: birds that traveled farther north were less likely to have their nests ravaged by foxes and other predators. But little other evidence for this kind of phenomena exists.

In the new study, Skov, along with colleagues from Sweden and Switzerland, attached passive integrated transponder (PIT) tags to more than 2,200 roach living in two lakes in Denmark. Every tag had a unique identifier code, allowing the team to distinguish each individual fish. At the inlets and outlets of each stream, the researchers set up antennas, which picked up signals from the PIT tags. "We knew the position of all of these tagged fish, allowing us to calculate how many days they spent in the stream and how much time they spent in the lake," Skov told LiveScience.

The researchers also knew cormorants roosted and bred near the lakes, while preying on roach, among other fish. With a device not so different from a minesweeper, they combed the cormorants' habitat, searching for tags that were pooped out. [The 10 Weirdest Animal Discoveries]

Analyzing the data from the tags, they saw a large variation in the amount of time the fish spent out of the lakes. Some fish spent five months in the streams, while others would visit the streams four or five times in a single winter. "But there was a consistent pattern," Skov said. "The longer (the fish) spent in the stream, the smaller their probability of predation."

For example, in 2008, small fish that stayed in Lake Loldrup the entire winter had about a 20 percent chance of getting eaten, but this probability dropped to about 10 percent if they stayed out of the lake for 100 days. Large roach (around 10 inches, or 25 centimeters, in length or more) showed the same trend, but overall were more likely to get eaten than small fish — they had a 40 percent chance of being preyed upon if they stayed in Lake Loldrup for the full 2008 winter.

Interestingly, the choice to migrate wasn't risk free. During winter food becomes scarce in the lakes, but there's practically nothing to eat in the streams, Skov said.

Why some, but not all?
Given how much safer the streams appear to be during the chilly months, one can't help but wonder why some roach stay behind in the lakes. The researchers don't have the full picture yet, but their previous research has uncovered clues.

In one study they found that physically fit fish were more likely to migrate than those in poor physical condition. The researchers also found that the fish's personality matters, as bold fish are more likely to migrate than shy fish. "So it's pretty complicated why some fish stay behind," Skov said.

Skov thinks the research will help scientists understand what drives migration and how different migrations evolve. "Here's support for one of the most underexplored ideas as to why animals migrate," he said, adding that he's interested in seeing how adaptive the roach's behavior is and if the fish would continue to migrate when there's no cormorant threat.

Future research may even show that other animals migrate to escape predators. "I could easily imagine that's the case," Skov said.

The research was detailed online Tuesday in the journal Biology Letters.

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NASA, ESA and A. Field (STScI)

This illustration shows the disk of our Milky Way galaxy, surrounded by a faint halo of old stars. Hubble Space Telescope measurements of 13 halo stars' motion indicate the possible presence of a shell in the halo, which may have formed from the accretion of a dwarf galaxy.

By Mike Wall
Space.com

The Milky Way's far outer reaches may harbor a shell of stars left over from a long-ago act of galactic cannibalism, a new study suggests.

The finding supports the idea that our Milky Way has continued to grow over the eons by gobbling up smaller satellite galaxies, researchers said. And the results may help astronomers better understand how mass is distributed throughout the galaxy, which could shed light on the mysterious dark matter that's thought to make up more than 80 percent of all matter in the universe.

In the new study, scientists used NASA's Hubble Space Telescope to precisely measure the motion of 13 stars in the Milky Way's ancient outer halo, about 80,000 light-years from the galactic center. They picked the stars out of seven years' worth of archival Hubble observations, which were acquired when the telescope was staring at the neighboring Andromeda galaxy.

Identifying the handful of far-flung Milky Way residents was no picnic, as each Hubble image contained more than 100,000 stars. [Stunning Photos of Our Milky Way Galaxy]

"It was like finding needles in a haystack," co-author Roeland van der Marel of the Space Telescope Science Institute in Baltimore said in a statement.

The team found that the outer halo stars had a surprisingly high level of sideways, or tangential, motion relative to their radial motion (which describes movement toward or away from the Milky Way's core).

The existence of a shell structure — which can be created by the accretion of a satellite galaxy — could explain the halo stars' unexpected motion, researchers said, noting that shell-like features have been observed around other galaxies.

"What may be happening is that the stars are moving quite slowly because they are at the apocenter, the farthest point in their orbit about the hub of our Milky Way," lead author Alis Deason of the University of California, Santa Cruz, said in a statement. "The slowdown creates a pileup of stars as they loop around in their path and travel back towards the galaxy. So their in and out or radial motion decreases compared with their sideways or tangential motion."

Deason and her colleagues plan to study more outer halo stars to determine if the shell at 80,000 light-years really does exist. Their overall goals are to gain a better understanding of the Milky Way's formation and evolution, and to calculate an accurate mass for the galaxy.

This latter aim has proven elusive to date.

"Until now, what we have been missing is the stars’ tangential motion, which is a key component," Deason said. "The tangential motion will allow us to better measure the total mass distribution of the galaxy, which is dominated by dark matter. By studying the mass distribution, we can see whether it follows the same distribution as predicted in theories of structure formation."

The new study has been accepted for publication in The Astrophysical Journal.

Follow Space.com senior writer Mike Wall on Twitter @michaeldwall or Space.com @Spacedotcom. We're also on Facebook and Google+.

• Our Milky Way Galaxy: A Traveler's Guide (Infographic)
• Milky Way Quiz: Test Your Galaxy Smarts
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Franky Bossuyt

The male alpine Ichthyosaura alpestris newt knows that it isn't the tail waving that attracts the ladies, but the pheromones that he uses.

By Joseph Castro
LiveScience

It may be time to crown male newts as the female-arousing kings — the amphibians release powerful pheromones that put females in the mood to mate with practically any adult around, even other females from different newt species, new research shows.

"The females react as if they're under the influence of drugs," said lead researcher Franky Bossuyt, a biologist at Vrije Universiteit Brussel (Free University of Brussels) in Belgium. "We were convinced that if we put in a plastic toy moving at the right speed, they would follow it."

Newts typically live on land as adults and mate exclusively in water. During the breeding season, males adopt intense color patterns and grow skin extensions on their legs, tail and crest. These changes are thought to make males more attractive to females.

When two newts meet, the male releases pheromones and waves his tail, sending the chemical signals to the female. They then play out a mating dance akin to a short game of tag, with the female following after the male. To let him know she's ready to get down to business, the female touches the male's tail with her nose, prompting him to deposit his spermatophore — a jellylike mass containing sperm— onto a substrate in the water, such as a leaf. Finally, he leads the female over the sperm packet, which sticks to her cloaca (the orifice leading to intestinal, reproductive and urinary tracts), resulting in insemination.

For years, scientists thought males waved their tails to disperse "attractant pheromones," which broadcast the male's presence and bring newt pairs together. But there's a problem with this idea: The newts have already introduced themselves before the male waves his tail. "The females are not attracted to the males by the tail-waving, at least with the newts I've seen," Bossuyt said.

Instead, the researchers thought, the tail fanning might disperse "courtship pheromones" that alter the female's behavior to stimulate mating.

Newt mating game
To find out, researchers placed male-female pairs of alpine newts (Ichthyosaura alpestris) and palmate newts (Lissotriton helveticus) into water-filled plastic containers for receptivity tests. The newts passed the test and were ready for the next phase if they completed the courtship ritual (females weren't allowed to complete the insemination).

The team then put two-female pairs into pheromone-infused courtship water; some pairs consisted of two alpine newts, other pairs had one female of each species. If the water contained pheromones from a male of her species, the female would desperately try to court the other female. In some cases, two female alpine newts tried to follow each other, resulting in the pair circling one another. In some two-species trials, one female chased after another, even as the unreceptive partner tried to escape the container. [See video of the sex-crazed newts]

But the amphibians didn't remain patient forever. Not receiving the spermatophore she expected, the courting female eventually started waving her tail at her partner, possibly sending out pheromones.

Frustrated females
"Female tale-waving is a kind of frustration behavior," Bossuyt explained, adding that females also tail-waved in receptivity tests to get males to continue courtship after researchers removed the spermatophores. In natural settings, this behavior probably happens only in uncommon situations, such as when a male is too tired for courtship. "So female tail-waving likely happens in nature, but you will not easily observe it," he said.

The results suggest the pheromones don't just announce the male's arrival, given how they induced such an overpowering mating reaction in the females. The researchers think males may have evolved such potent pheromones out of necessity, since newts often breed in turbid water with other newt species, making it difficult to mate based on vision alone.

It seems a male newt's flashy appearance matters little to females: It's all about his smell.

The research was detailed online this month in the journal PLOS ONE.

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Franco M. Giani - Milano - Italy

The unwrapped shoe bundle showing the two pairs of children's shoes and the adult isolated adult shoe.

By Owen Jarus
LiveScience

More than 2,000 years ago, at a time when Egypt was ruled by a dynasty of kings of Greek descent, someone, perhaps a group of people, hid away some of the most valuable possessions they had — their shoes.

Seven shoes were deposited in a jar in an Egyptian temple in Luxor, three pairs and a single one. Two pairs were originally worn by children and were only about 7 inches (18 centimeters) long. Using palm fiber string, the child shoes were tied together within the single shoe (it was larger and meant for an adult) and put in the jar. Another pair of shoes, more than 9 inches (24 cm) long that had been worn by a limping adult, was also inserted in the jar.

The shoe-filled jar, along with two other jars, had been "deliberately placed in a small space between two mudbrick walls," writes archaeologist Angelo Sesana in a report published in the journal Memnonia.

 Whoever deposited the shoes never returned to collect them, and they were forgotten, until now. [See Photos of the Ancient Egyptian Shoes]

In 2004, an Italian archaeological expedition team, led by Sesana, rediscovered the shoes. The archaeologists gave André Veldmeijer, an expert in ancient Egyptian footwear, access to photographs that show the finds.

Franco M. Giani - Milano - Italy

Archaeologists discovered seven shoes, which appear to be made out of bovine, within a jar in an Egyptian temple. The shoes date back more than 2,000 years and this picture shows the inside of the jar before the shoes were removed.

"The find is extraordinary as the shoes were in pristine condition and still supple upon discovery," writes Veldmeijer in the most recent edition of the Journal of the American Research Center in Egypt. Unfortunately, after being unearthed the shoes became brittle and "extremely fragile," he added.

Pricey shoes
Veldmeijer's analysis suggests the shoes may have been foreign-made and were "relatively expensive." Sandals were the more common footwear in Egypt and the style and quality of these seven shoes was such that "everybody would look at you," and "it would give you much more status because you had these expensive pair of shoes," said Veldmeijer, assistant director for Egyptology of the Netherlands-Flemish Institute in Cairo.

The date of the shoes is based on the jar they were found in and the other two  jars, as well as the stratigraphy, or layering of sediments, of the area. It may be possible in the future to carbon date the shoes to confirm their age.

Why they were left in the temple in antiquity and not retrieved is a mystery. "There's no reason to store them without having the intention of getting them back at some point," Veldmeijer said in an interview with LiveScience, adding that there could have been some kind of unrest that forced the owners of the shoes to deposit them and flee hastily. The temple itself predates the shoes by more than 1,000 years and was originally built for pharaoh Amenhotep II (1424-1398 B.C.).

Design discoveries
Veldmeijer made a number of shoe design discoveries. He found that the people who wore the seven shoes would have tied them using what researchers call "tailed toggles." Leather strips at the top of the shoes would form knots that would be passed through openings to close the shoes. After they were closed, a long strip of leather would have hung down, decoratively, at either side. The shoes are made out of leather, which is likely bovine.

Most surprising was that the isolated shoe had what shoemakers call a "rand," a device that until now was thought to have been first used in medieval Europe. A rand is a folded leather strip that would go between the sole of the shoe and the upper part, reinforcing the stitching as the "the upper is very prone to tear apart at the stitch holes," he explained. The device would've been useful in muddy weather when shoes are under pressure, as it makes the seam much more resistant to water.

In the dry (and generally not muddy) climate of ancient Egypt, he said that it's a surprising innovation and seems to indicate the seven shoes were constructed somewhere abroad.

Health discoveries
The shoes also provided insight into the health of the people wearing them. In the case of the isolated shoe, he found a "semi-circular protruding area" that could be a sign of a condition called Hallux Valgus, more popularly known as a bunion. [The 9 Most Bizarre Medical Conditions]

"In this condition, the big toe starts to deviate inward towards the other toes," Veldmeijer writes in the journal article. "Although hereditary, it can also develop as a result of close-fitting shoes, although other scholars dispute this ...."

Another curious find came from the pair of adult shoes. He found that the left shoe had more patches and evidence of repair than the shoe on the right. "The shoe was exposed to unequal pressure," he said, showing that the person who wore it "walked with a limp, otherwise the wear would have been far more equal."

Still, despite their medical problems, and the wear and tear on the shoes, the people who wore them were careful to keep up with repairs, Veldmeijer said. They did not throw them away like modern-day Westerners tend to do with old running shoes.

"These shoes were highly prized commodities."

Veldmeijer hopes to have the opportunity to examine the shoes, now under the care of the Ministry of State for Antiquities, firsthand.

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By Tanya Lewis
LiveScience

As far back as we know, animals have been home to microbes. Scientists have known for some time that these tiny tenants have the ability to make humans powerfully sick, while others are vital to maintaining the body's normal flora and fauna.

Collectively, the microbes inside everyone make up the "microbiome" — what microbiologist Martin Blaser of the NYU School of Medicine defines as "all the organisms that call us home, that live in us and that interact with each other and with ourselves."

These teensy creatures, from bacteria and fungi to protozoans (mostly single-celled animal-like organisms), have a surprisingly rich story to tell. Here are five fascinating facts about the critters that call your body home.

Your body has more microbes than human cells
The human body is teeming with microbes. A number that gets bandied about is that there are 10 times as many bacterial cells as human cells inside you. While no one's bothered to count them, "the exact number doesn't matter as much as the idea that there are certainly more bacterial cells in our body than human cells," Blaser told LiveScience. As humans have evolved, these microbes have evolved with them. A whole lot of viruses call humans home, too.

And 2013 marks the end of the Human Microbiome Project, a five-year effort involving hundreds of scientists to catalogue the microbiome of human beings. [Image Gallery: Belly Button Bacteria]

You are born bacteria-free
With all these bacteria living inside, it seems natural that humans would just be born with them. Not so. According to Blaser, people are born without bacteria, and acquire them in the first few years of life. Babies get their first dose of microbes as they're passing through their mother's birth canal. (Of course, babies born by Caesarean section don't acquire their microbes this way. In fact, studies show that C-section babies have a markedly different microbiota from vaginal birth babies, and may be at higher risk for certain types of allergies and obesity.)

A baby acquires most of its microbiome by the age of 3, Blaser said — during a time when the baby's metabolic, immune, cognitive and reproductive systems are undergoing extensive development.

Bacteria can be good and bad for you
You're probably aware that while some germs can make you sick, others are important for keeping you healthy and fending off infections. Sometimes, the same bacteria can do both.

Consider Helicobacter pylori, the bacteria responsible for causing stomach ulcers. The bacteria were once found in the majority of the population, but their prevalence has steadily been decreasing, and today only about half of the world's population has it. Most of them do not have symptoms, but a small number develop painful ulcers in an acidic part of the digestive tract (a finding that earned a Nobel Prize in Medicine in 2005).

Helicobacter infections are treatable with antibiotics, but there's a twist: Blaser and colleagues have found the absence of Helicobacterappears to be associated with diseases of the esophagus, such as reflux esophagitis and certain cancers of the esophagus. In other words, Helicobactermay be bad for our stomachs, but good for our throats. Though not all scientists agree, "There's a big body of evidence that Helicobacter has both biological costs and biological benefits," Blaser told LiveScience. [Tiny & Nasty: Images of Things That Make Us Sick]

Antibiotics can cause asthma and obesity
Penicillin was a major breakthrough when Alexander Fleming discovered it in 1928. Antibiotics have enjoyed widespread popularity ever since, but antibiotics overusehas given rise to deadly strains of antibiotic-resistant bacteria, such as Methicillin-resistant Staphylococcus aureus (MRSA).

Now, there's some evidence that antibiotics also increase the risk for developing asthma, inflammatory bowel disease and obesity.

Of course, there are times when antibiotics are necessary. "I would never withhold antibiotics from a very sick child," Blaser told LiveScience. Nevertheless, he said, many common childhood ailments, from ear infections or throat infections, go away by themselves.

(Store-bought) probiotics are overrated
The recognition that bacteria can be good for you has spawned something of a craze in probiotic supplements, consisting of live microbes purported to bestow health benefits. Many people take them after a course of antibiotics. But do they actually work?

"The concept of a probiotic to help re-establish our baseline microbiota after an antibiotic is a good concept," Blaser told LiveScience. "But the idea that, of all thousand species in our bodies, taking a single species that comes from cow or cheese is naïve." Current probiotics are very well marketed, Blaser said, but there's not much benefit. He does think medicine will one day develop probiotics that will be used to treat illness, but as of now, "it's a very young field," he said.

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NASA / JSC

Looking out at the Earth's surface from the International Space Station, astronauts frequently observe sunglint highlighting both ocean and inland water surfaces.

By Clara Moskowitz
LiveScience

The coast of the northeast United States is silhouetted against the shimmering water of Cape Cod Bay and Long Island Sound in a new photo captured by astronauts on the International Space Station.

The phenomenon of light from a setting sun reflecting off water to create a shining, mirrorlike surface is called sunglint, and is evident throughout the photo.

"The Atlantic Ocean — including Cape Cod Bay and Buzzards Bay, along the coastlines of Massachusetts and Rhode Island — has a burnished, mirrorlike appearance in this image," the NASA's Earth Observatory wrote. "This is due to sunlight reflected off the water surface back towards the astronaut-photographer."

The photo was taken on Feb. 14 at 4:26 p.m. EST by the space station's Expedition 34 crew, which includes commander Kevin Ford of NASA, as well as U.S. astronaut Tom Marshburn, Canadian astronaut Chris Hadfield, and Russian cosmonauts Oleg Novitskiy, Evgeny Tarelkin and Roman Romanenko.

At that time of day, the sun was low on the horizon, as evidenced by the wide extent of the sunglint effect, which reaches all the way from Long Island Sound to the waters of Chesapeake Bay, more than 250 miles (400 kilometers) away. From the vantage of the International Space Station, 260 miles (420 km) above Earth, much of the region is visible, as well as the limb of the planet and its thin atmosphere fading away into the blackness of space.

On the photo's right side, the waters off the Massachusetts coast and in Long Island Sound are especially bright where the peak reflection point is, according to the Earth Observatory.

The photo shows the northeast United States just days after a powerful blizzard blanketed many areas in heavy snow on Feb. 9.

"There is little in this image to indicate that the region was still recovering from a major winter storm that dropped almost one meter (three feet) of snow over much of the northeastern USA less than a week earlier," the Earth Observatory wrote.

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Al Grillo / AP file

This Alaska sea otter from the waters off of the Aleutian Island of Adak looks healthy enough. Its brethren in England aren't faring so well.

By Marc Lallanilla
LiveScience

Scientists are concerned about the deformed sex organs of England's otters — and what it might mean for humans.

The furry mammals are found in rivers throughout Britain, but male otters aren't what they used to be. An alarming number of them now have shrunken penis bones (baculum), as well as undescended testicles (cryptorchidism) and cysts on sperm-carrying tubes, according to a new report written by Cardiff University scientists.

The results are based on analyses of samples from 755 otter carcasses collected around England and Wales between 1992 and 2009.

"We were surprised to see the reduction in the baculum weight," Elizabeth Chadwick, project manager at the Cardiff University Otter Project, told the BBC. "(It's) certainly something that needs further investigation."

Though scientists aren't yet able to identify a single cause for the deformed sex organs, one leading suspect is a class of chemical pollutants known as endocrine disruptors.

Endocrine-disrupting chemicals (EDCs) alter the hormone balance of humans and animals. An unborn fetus is particularly vulnerable to the effects of endocrine disruptors, since the development of sex organs in the womb is largely controlled by hormones such as testosterone and estrogen.

The plastic additive Bisphenol A, or BPA is one hormone disruptor that's consistently been cited as a concern for women of childbearing age and their babies. Other endocrine-disrupting compounds are found in pharmaceuticals, pesticides and other common household products.

Though scientists are still sifting through the evidence, there are many researchers who believe the prevalence of endocrine disruptors might be linked to a worldwide drop in sperm quality and quantity in humans. [Sexy Swimmers: 7 Odd Facts About Sperm]

As the top predator in England's rivers and lakes, the BBC reports, otters are an indicator species whose health reveals much about the well-being of the entire aquatic ecosystem. Health problems discovered in otters, Chadwick said, "could be a warning for all mammals really, which include us humans."

"These findings highlight that it is time to end the complacency about the effects of pollutants on male reproductive health, particularly as some of the effects reported in otters may be caused by the same EDCs that are suspected to contribute to the declining trends in men's reproductive health and cause testicular cancer, undescended testes and low sperm count," Gwynne Lyons, director of Chemicals, Health and Environment Monitoring Trust (CHEM), which co-authored the report with Cardiff University, said in a statement.

Contact Marc Lallanilla at mlallanilla@techmedianetwork.com. Follow him on Twitter @MarcLallanilla. Follow LiveScience on Twitter @livescience. We're also on Facebook and Google+.

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University of Dundee

Researchers have reconstructed the face of Arsinoe IV, Cleopatra's sister, based on measurements from a skull discovered in Ephesus.

By Stephanie Pappas
LiveScience

A Viennese archaeologist lecturing in North Carolina this week claims to have identified the bones of Cleopatra's murdered sister or half-sister. But not everyone is convinced.

That's because the evidence linking the bones, discovered in an ancient Greek city, to Cleopatra's sibling Arsinoe IV is largely circumstantial. A DNA test was attempted, said Hilke Thur, an archaeologist at the Austrian Academy of Sciences and a former director of excavations at the site where the bones were found. However, the 2,000-year-old bones had been moved and handled too many times to get uncontaminated results.

"It didn't bring the results we hoped to find," Thur told the Charlotte Observer. She will lecture on her research March 1 at the North Carolina Museum of History in Raleigh.

Bloody family history
Arsinoe IV was Cleopatra's younger half-sister or sister, both of them fathered by Ptolemy XII Auletes, though whether they shared a mother is not clear. Ptolemaic family politics were tough: When Ptolemy XII died, he made Cleopatra and her brother Ptolemy XIII joint rulers, but Ptolemy soon ousted Cleopatra. Julius Caesar took Cleopatra's side in the family fight for power, while Arsinoe joined the Egyptian army resisting Caesar and the Roman forces. [Cleopatra and Olympias: Top 12 Warrior Moms in History]

Rome won out, and Arsinoe was taken captive. She was allowed to live in exile in Ephesus, an ancient Greek city in what is now Turkey. However, Cleopatra saw her half-sister as a threat and had her murdered in 41 B.C.

Fast forward to 1904. That year, archaeologists began excavating a ruined structure in Ephesus known as the Octagon for its shape. In 1926, they revealed a burial chamber in the Octagon, holding the bones of a young woman.

Thur argues that the date of the tomb (sometime in the second half of the first century B.C.) and the illustrious within-city location of the grave point to the occupant being Arsinoe IV herself. Thur also believes the octagonal shape may echo that of the great Lighthouse of Alexandria, one of the Seven Wonders of the Ancient World. That would make the tomb an homage to Arsinoe's hometown, Egypt's ancient capital, Alexandria. 

Controversial claim
The skull attributed to Arsinoe disappeared in Germany during World War II, but Thur found the rest of the bones in two niches in the burial chamber in 1985. The remains have been debated every step of the way. Forensic analysis revealed them to belong to a girl of 15 or 16, which would make Arsinoe surprisingly young for someone who was supposed to have played a major leadership role in a war against Rome years before her death. Thur dismisses those criticisms.

"This academic questioning is normal," she told the News-Observer. "It happens. It's a kind of jealousy."

In 2009, a BBC documentary, "Cleopatra: Portrait of a Killer," trumpeted the claim that the bones are Arsinoe's. At the time, the most controversial findings centered on the body's lost skull. Measurements and photographs of the incomplete skull remain in historical records and were used to reconstruct the dead woman's face.

More about Cleopatra from NBCNews.com

From the reconstruction, Thur and her colleagues concluded that Arsinoe had an African mother (the Ptolemies were an ethnically Greek dynasty). That conclusion led to splashy headlines suggesting that Cleopatra, too, was African.

But classicists say the conclusions are shaky.

"We get this skull business and having Arsinoe's ethnicity actually being determined from a reconstructed skull based on measurements taken in the 1920s?" wrote David Meadows, a Canadian classicist and teacher, on his blog rogueclassicism.

Not only that, but Cleopatra and Arsinoe may not have shared a mother.

"In that case, the ethnic argument goes largely out of the window," Cambridge classics professor Mary Beard wrote in the Times Literary Supplement in 2009.

Without more testing, the bones remain in identification limbo.

"One of my colleagues on the project told me two years ago there is currently no other method to really determine more," Thur told the News-Observer. "But he thinks there may be new methods developing. There is hope."

Follow Stephanie Pappas on Twitter @sipappas or LiveScience @livescience. We're also on Facebook and Google+.

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Steven Cummer

A gigantic jet captured above a storm in North Carolina in 2009.

By Elizabeth Howell
LiveScience

A rare glimpse of a "gigantic jet" — a huge and mysterious burst of lightning that connects a thunderstorm with the upper atmosphere — was made over China in 2010 and was recently described by scientists.

The gigantic jet took place in eastern China on Aug. 12, 2010 — the farthest a ground-based one has ever been observed from the equator, according to the research team.

Previous jets were mainly seen in tropical or subtropical regions, but this one took place around 35 degrees latitude, about the same as the southern part of Tennessee in the United States.

"This is the first report from mainland China," lead researcher Jing Yang, an atmospheric scientist with the Chinese Academy of Sciences in Beijing, told OurAmazingPlanet. The results were recently published in the Chinese Science Bulletin.

Researchers got a good look at the storm using a variety of tools, including Doppler radar data and weather pictures in the infrared band of radiation.

The gigantic jet peaked at about 55 miles (89 kilometers) above the ground, far above the cloudtops that were measured with Doppler radar at an altitude of 11 miles (17 km). [Infographic: Earth's Atmosphere Top to Bottom]

Yang added that her team had possibly seen another gigantic jet in the same area during a different thunderstorm, but said they needed to recheck the data to confirm.

"It's not as clear as this one if it is a gigantic jet or not," she said.

It wasn't until the last century that electrical activity above thunderclouds was scientifically proven, although rumors based on undocumented observations circulated long before that time.

These electrical discharges can take several forms, such as sprites (orange-red flashes) and blue jets, which appear as blue cones.

The first confirmed gigantic jet was reported in 2001, after American researchers saw a blue jet reaching 44 miles (70 km) above the clouds at the Arecibo Observatory in Puerto Rico. This was nearly double the 26-mile (42 km) limit for jets that was previously observed.

Two years later, researchers described shapes such as "tree jets" and "carrot jets" that they spotted during a 2002 thunderstorm over the South China Sea near the Philippines.

While scientists are still trying to understand how these gigantic jets work, they believe the jets balance out the electrical charge during thunderstorms by discharging the ionosphere — a part of the upper atmosphere filled with charged particles.

Follow Elizabeth Howell @howellspace, or OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.

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ESA

This artist's impression shows NASA's Cassini spacecraft exploring the magnetic environment of Saturn. Saturn's magnetosphere is depicted in gray, while the complex bow shock region — the shock wave in the solar wind that surrounds the magnetosphere — is in blue. The image is not to scale.

By Mike Wall
Space.com

NASA's Cassini spacecraft has spotted solar particles moving at incredible speeds near Saturn, giving scientists a rare up-close look at phenomena that occur during dramatic star explosions.

The particles flowed from the sun during a strong blast of solar wind, then plowed into Saturn's magnetic field shortly thereafter. This encounter, which Cassini observed in February 2007, created a shockwave that accelerated the particles to super-high energies, scientists said.

Similar shockwaves commonly form in the aftermath of massive star explosions called supernovas, ramping up nearby particles to nearly the speed of light. Researchers think supernova shockwaves are the primary source of cosmic rays, high-energy particles that pervade our Milky Way galaxy and slam into Earth's atmosphere continuously.

It can be tough to study distant supernovas and their shockwaves, so Cassini's observations provide a welcome proxy, scientists said.

"Cassini has essentially given us the capability of studying the nature of a supernova shock in situ in our own solar system, bridging the gap to distant high-energy astrophysical phenomena that are usually only studied remotely," Adam Masters, of the Institute of Space and Astronautical Science, Sagamihara, Japan, said in a statement.

Masters is lead author of a study reporting the Cassini findings, which was published this week in the journal Nature Physics.

The Saturn shockwave may be the most powerful ever detected at the ringed planet and suggests that certain kinds of shocks can be surprisingly efficient particle accelerators, researchers said.

The $3.2 billion Cassini mission is a joint effort of NASA, the European Space Agency and the Italian Space Agency. Cassini launched in 1997 and arrived at the Saturn system in 2004, delivering a lander called Huygens to the planet's huge moon Titan in January 2005.

Cassini will continue studying the ringed planet and its many moons for several years to come; Cassini's mission has been extended through at least 2017.

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Photo by Bill Ingalls/NASA via Getty Images)

Neil Armstrong speaks during a celebration dinner at Ohio State University honoring former U.S. Sen. and astronaut John Glenn's 50th anniversary of his flight aboard Friendship 7 on February 20, 2012 in Columbus, Ohio.

Associated Press

WASHINGTON — The House has approved a bill to rename a NASA flight center in California for the late astronaut Neil Armstrong, the first man to walk on the moon.

The measure, which passed on a 394-0 vote, would rename the Dryden Flight Research Center at Edwards Air Force Base as the Neil A. Armstrong Flight Research Center.

Armstrong, who died in August 2012, commanded the historic landing of the Apollo 11 spacecraft on the moon in 1969. He made "one giant leap for mankind" with a small step onto the moon. He was also a test pilot who worked at the center for seven years.

The bill would also rename the center's test range for the late Hugh L. Dryden, former NASA deputy administrator.

The measure goes to the Senate for consideration.

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Unviersity at Buffalo

An unreinforced brick wall collapsed after a shake table test simulating a magnitude-6.3 earthquake.

By Becky Oskin
LiveScience

New York City's brick houses would fall apart if an earthquake the size of the one that struck in Christchurch, New Zealand in 2011 hit near the metropolis, a recent earthquake simulation found.

The shake table test broke an unreinforced brick wall in half on Feb. 18 at the University at Buffalo's Multidisciplinary Center for Earthquake Engineering Research.

The 14-foot (4-meter) wall, built with materials such as 100-year-old brick, simulates the central walls of the turn-of-the-century row houses (often called brownstones) found in New York, researchers said. The shake table first mimicked powerful magnitude 5.8 earthquake waves, similar to the 2011 Virginia earthquake, rocking back and forth beneath the walls. But it took a magnitude 6.3 earthquake, which is 5.6 times stronger, to snap the unreinforced wall. [Watch the shake table test]

Unreinforced masonry buildings account for about 80 percent of New York City's housing and appear commonly throughout the East Coast, said structural engineer Juan Aleman, a graduate student at the university.

The good news is that a similar brick wall, reinforced with steel rods and bolts as is done in earthquake-prone California, withstood the shaking. "We're trying to understand, 'How much better does a building perform when it has been retrofitted?'" said Gilberto Mosqueda, a structural engineering professor at the University of California, San Diego, who took part in the test.

Data from the simulation will help Aleman model New York City's vulnerability to earthquakes. "We will try to understand what will happen in a real building if an earthquake of magnitude 5.0 or greater happens," he told OurAmazingPlanet.

The 2011 Virginia earthquake, which hit a sparsely populated region, destroyed as many as seven houses and caused major damage to 120 other buildings in the surrounding region, according to government reports.

Reach Becky Oskin at boskin@techmedianetwork.com. Follow her on Twitter @beckyoskin. Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.

• The 10 Biggest Earthquakes in History
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NASA / ESA

NASA's Hubble Space Telescope snapped this shot of Mars on Aug. 26, 2003, when the Red Planet was 34.7 million miles from Earth. The picture was taken just 11 hours before Mars made its closest approach to us in 60,000 years.

By Rod Pyle
Space.com

LOS ANGELES — While Mars was likely a more hospitable place in its wetter, warmer past, the Red Planet may still be capable of supporting microbial life today, some scientists say.

Ongoing research in Mars-like places such as Antarctica and Chile's Atacama Desert shows that microbes can eke out a living in extremely cold and dry environments, several researchers stressed at "The Present-Day Habitability of Mars" conference held here at the University of California Los Angeles this month.

And not all parts of the Red Planet's surface may be arid currently — at least not all the time. Evidence is building that liquid water might flow seasonally at some Martian sites, potentially providing a haven for life as we know it.

"We certainly can't rule out the possibility that it's habitable today," said Alfred McEwen of the University of Arizona, principal investigator for the HiRise camera aboard NASA's Mars Reconnaissance Orbiter spacecraft. [The Search for Life on Mars: A Photo Timeline]

NASA / JPL-Caltech / Univ. of Arizona

This image combining orbital imagery with 3-D modeling shows flows that appear in spring and summer on a slope inside Mars' Newton crater.

Surface water on Mars?
McEwen discussed some intriguing observations by HiRise, which suggest that briny water may flow down steep Martian slopes during the local spring and summer.

Sixteen such sites have been identified to date, mostly on the slopes of the huge Valles Marineris canyon complex, McEwen said. The tracks seem to repeat seasonally as the syrupy fluids descend along weather-worn pathways.

While the brines may originate underground, Caltech's Edwin Kite noted, there is an increasing suspicion that a process known as deliquescence — in which moisture present in the atmosphere is gathered by compounds on the ground, allowing it to become a liquid — may be responsible.

Astrobiologists are keen to learn more about these brines, for not much is known about them at the moment.

"Briny water on Mars may or may not be habitable to microbes, either from Earth or from Mars," McEwen said.

NASA / JPL-Caltech / MSSS

NASA's Curiosity rover found evidence for an ancient, flowing stream on Mars at a few sites, including the rock outcrop pictured here, which the science team has named "Hottah" after Hottah Lake in Canada's Northwest Territories. This image mosaic was taken by Curiosity's 100-millimeter Mastcam telephoto lens.

Hardy microbes
Martian life may be able to survive even in places where water doesn't seep and flow, some scientists stressed.

For example, microbes here on Earth make a living in the Atacama and the dry valleys of Antarctica, both of which are extremely cold and arid, said Chris McKay of NASA's Ames Research Center in Moffett Field, Calif.

Antarctic sites also receive seasonally high ultraviolet radiation doses thanks to a hole in the ozone layer that tends to develop every August through November. This provides yet another parallel to Mars, whose thin atmosphere and lack of a protective magnetic field make the planet more radiation-bombarded than Earth.

In the Antarctic dry valleys, McKay said, organisms dwell within rocks, just deep enough to be shielded from the worst of the UV but close enough to the surface to receive the benefits of photosynthesis. Something similar might be happening on Mars today, if life ever evolved there.

McKay also discussed deliquescence, which in the Atacama allows salts to gather enough water to support the existence of life.

McKay offered some advice to NASA's Mars rover Curiosity, which landed in August to determine whether Mars could ever have supported microbial life: "Watch for salt along the road!"

A possible energy source
A number of presenters spent some time talking about perchlorate, a chlorine-containing chemical that NASA's Phoenix lander spotted near the Martian north pole in 2008.

McKay and other researchers think perchlorate may be the reason that NASA's twin Viking landers didn't detect any organic compounds — the carbon-containing building blocks of life as we know it — on the Red Planet back in the 1970s.

The Vikings vaporized Martian soil and looked for any organics boiling off. They found nothing but a few chlorine compounds that were attributed to contamination. But after Phoenix's perchlorate find, McKay and some other researchers performed an experiment.

They added perchlorate to some desert dirt from Chile known to contain organics. They heated the soil up and found the same chlorine compounds the Vikings did, suggesting that organics may have been present in the Vikings' samples but were broken down by the combination of heat and perchlorate.

While this backstory is interesting in its own right, perchlorate is also relevant to the possible habitability of present-day Mars.

"Perchlorate, it turns out, is a potent chemoautotrophic energy source," said Carol Stoker, also of NASA Ames, noting that the chemical could potentially sustain microbes in the dark Martian subsurface, where photosynthesis is not an option.

And some Earth microbes use perchlorate for food, so that could be happening on Mars as well, scientists have pointed out.

"The Present-Day Habitability of Mars" took place Feb. 4-5 and was co-hosted by the NASA Astrobiology institute and the UK Center for Astrobiology. Archived videos of conference presentations are available here.

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