900-Lb. Ancient Croc Tore Through Turtles, Battled Snakes

It was 16 feet (4.8 meters) long and tipped the scales at 900 lbs. (408 kilograms). With a blunt snout and powerful bite, it ate turtles and battled monster snakes. Now this extinct dyrosaur, a type of crocodilian, which roamed an ancient rainforest a few million years after the dinosaurs died, has a scientific name.

It's called Anthracosuchus balrogus after the fiery Balrog that lurked deep in the Middle-Earth mines of Moria in J.R.R. Tolkien's novel "The Lord of the Rings."

"Much like that giant beast, Anthracosuchus balrogus was from deep within a mine after 60 million years trapped within the rocks of tropical South America," study researcher Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History, told Live Science in an email.

Four specimens of the new species were unearthed in a layer of rock in the fossil-rich Cerrejón coal mine of northern Colombia, where scientists previously have found huge turtles with shells as thick as high-school textbooks and skeletons of the world's largest snake, Titanoboa, a 48-foot-long (14.6 m) beast that recently starred in a Smithsonian Channel documentary.

A. balrogus is the third new species of ancient crocodilian found at Cerrejón, scientists say. (Another, Acherontisuchus guajiraensis, was described in the journal Palaeontology in 2011.) The newly named croc belonged to an intrepid family known as the dyrosaurids.

These creatures arose in Africa, paddled across the Atlantic Ocean to South America about 75 million years ago and remarkably survived the mass extinction that wiped out the dinosaurs about 65 million years ago, scientists say. Some dyrosaurid species, such as A. balrogus, adapted to freshwater ecosystems like the rainforest of Cerrejón, which was much warmer and swampier 60 million years ago than it is today.

"This group offers clues as to how animals survive extinctions and other catastrophes," Alex Hastings, a postdoctoral researcher at Martin Luther Universität Halle-Wittenberg and former graduate student at the Florida Museum of Natural History, said in a statement. "As we face climates that are warmer today, it is important to understand how animals responded in the past. This family of crocodyliforms in Cerrejón adapted and did very well despite incredible obstacles, which could speak to the ability of living crocodiles to adapt and overcome."

Read more at Discovery News

Early Dogs Helped Humans Hunt Mammoths

Early dogs may have helped human hunters track and kill mammoths in Ice Age Europe and Asia. The fierce dogs may have then guarded the meat from their wolf relatives.

Penn State archeologist Pat Shipman recently calculated that the age ranges of mammoths found in these ancient boneyards suggest that the animals were hunted, not just scavenged after a catastrophe killed an entire herd. Shipman suggested that the domestication of wolves, along with improvements in projectile weapons, may have allowed people to successfully hunt large numbers of mammoths. The journal Quaternary International published her results.

From approximately 40,000 to 15,000 years ago, human campsites from Siberia to central Europe contained tremendous numbers of mammoth bones, sometimes from more than 100 individual pachyderms. In many cases, humans constructed buildings using the mammoth bones, tusks and hides.

Shipman noted that high numbers of wild wolf and Arctic fox bones appear along with the mammoth bones. Dogs may have helped guard the mammoth meat by alerting people when other carnivores came sniffing around. The wolves and foxes were then killed and skinned for their pelts and meat.

Earlier archeological discoveries, published in the Journal of Archeological Sciences, described a breed of dog, or semi-domesticated wolf, from approximately 32,000 years ago in what is now Belgium, the Ukraine and Russia. Genetic and skeletal evidence show that the dog-like creature was different from known wolves, yet its genetic signature didn’t survive in modern dog populations. This could mean the mammoth-hunting dogs either died out, or interbred with other dogs and wolves until they became indistinguishable.

Read more at Discovery News

Violent Galaxy Cluster Smash Spawns Weird Radio Wiggle

When two clusters of galaxies collide, vast regions of space are energized by powerful shock waves, ripping through intergalactic gas and dust, triggering bright emissions across the electromagnetic spectrum. But what if four (yes, four!) galactic clusters slammed into one another?

In new observations captured by the NASA/ESA Hubble Space Telescope, NASA’s Chandra X-ray space observatory and the Karl G. Jansky Very Large Array (VLA), the complex violence of a galactic cluster four-way has been recorded 5 billion light-years distant and astronomers don’t yet fully understand what they are witnessing.

In this stunning composite image described today (Tuesday) at the American Astronomical Society’s meeting in Boston, Mass., the blue glow represents hot intergalactic gases emitting X-ray radiation as seen by Chandra. But the red wiggly structure threading through the vast cloud of colliding galaxies — which represents intense radio wave emissions as recorded by the ground-based VLA — is something of a conundrum.

“The complex shape of this region is unique; we’ve never spotted anything like this before,” said Reinout van Weeren, an Einstein Fellow at the Harvard-Smithsonian Center for Astrophysics. “The shape probably is the result of the multiple ongoing collisions.”

It is thought that the wiggly radio wave emitting structure is being formed by monstrous shock waves blasting through the intergalactic medium, accelerating the hot gas and dust. As these energized particles interact with the intertwined magnetic fields that are undoubtedly threading through the clusters, intense radio emissions are generated. This structure is therefore most likely magnetic in origin, but more research is needed to fully understand its nature.

In addition to this phenomenon, other radio emissions can be seen. The red straight line just below the wiggly structure is a foreground galaxy whose central black hole is blasting out two elongated jets of radio-bright material light-years through space. The other red structure in the bottom left is a radio galaxy that is likely falling into the colliding clusters’ immense gravitational well.

Read more at Discovery News

Space Telescope Gazes Deep Inside Powerful Solar Eruption

CMEs — coronal mass ejections — are some of the most energetic and powerful events that can regularly occur on our sun. Created by huge looping magnetic fields that rise up from deep inside our nearest star, carrying solar plasma along for the ride, a CME occurs when the magnetic field “snaps” and flings its load of stellar material out into the solar system.

If the outward-bound cloud of material happens to collide with Earth, usually several days later, the resulting geomagnetic storm effects can range from increased auroral activity across upper-to-middle latitudes to actual physical damage to satellite electronics and sensitive equipment on the ground.

One particularly powerful CME in 1989 illuminated auroras as far south as Florida and caused a blackout across the entire province of Québec!

On May 9 of this year a CME erupted from the sun and was caught on camera by NASA’s Interface Region Imaging Spectrograph (IRIS) spacecraft, the first to be captured by the orbiting observatory. Because IRIS is specially designed to observe close-up portions of the Sun’s chromosphere and transition region in high definition, this is the best view yet of what happens near the “surface” of the sun during such an event.

Because IRIS’ imaging area has to be programmed a day ahead of time, catching a CME in action involves quite a bit of luck.

“We focus in on active regions to try to see a flare or a CME,” said Bart De Pontieu, the IRIS science lead at Lockheed Martin Solar & Astrophysics Laboratory. “And then we wait and hope that we’ll catch something. This is the first clear CME for IRIS so the team is very excited.”

The video above shows the May 9 CME sending a huge gout of solar material streaming out from the sun at 1.5 million miles an hour, in an area about seven times the size of Earth.

From Discovery News

Because you can't eat just one: Star will swallow two planets

Two worlds orbiting a distant star are about to become a snack of cosmic proportions. Astronomers announced today that the planets Kepler-56b and Kepler-56c will be swallowed by their star in a short time by astronomical standards. Their ends will come in 130 million and 155 million years, respectively.

"As far as we know, this is the first time two known exoplanets in a single system have a predicted 'time of death,'" says lead author Gongjie Li of the Harvard-Smithsonian Center for Astrophysics (CfA).

She presented her research today at a meeting of the American Astronomical Society.

The Kepler-56 system provides a glimpse into the future of our solar system. In about five billion years our Sun will become a red giant star, swelling to immense proportions and engulfing Mercury and Venus.

The star Kepler-56 is becoming a red giant star as well. It already has ballooned out to four times the Sun's size. As it ages, it will continue to expand outward. Not only will the star grow larger, but its tides will get stronger, dragging its planets inward to their eventual doom.

Kepler-56b orbits its host star once every 10.5 days, while Kepler-56c orbits every 21.4 days. Both of them are much closer to their star than Mercury is to the Sun. As a result, they will meet their fate much faster. Li and her collaborators calculated the evolution of both the star's size (using the publicly available MESA code) and the planets' orbits to predict when the planets will be destroyed.

Even before they vanish, the two planets will be subjected to immense heating from the steadily growing star. Their atmospheres will begin to boil off, and the planets themselves will be stretched into egg shapes by stellar tides.

The only survivor in the system will be Kepler-56d, a gas giant planet circling in a 3.3-Earth-year orbit. It will watch from a safe distance as its two sibling worlds meet their demise.

The Kepler-56 planetary system also is notable for being the first "tilted" multiplanet system to be discovered. The orbits of the inner two planets are tipped significantly from the star's equator. This was unexpected since planets form from the same disk of gas and dust as the star, so they should orbit in nearly the same plane as the star's equator (as do the planets in our solar system).

Read more at Science Daily

'Neapolitan' exoplanets come in three flavors

The planets of our solar system come in two basic flavors, like vanilla and chocolate ice cream. We have small, rocky terrestrials like Earth and Mars, and large gas giants like Neptune and Jupiter. We're missing the astronomical equivalent of strawberry ice cream -- planets between about one and four times the size of Earth. NASA's Kepler mission has discovered that these types of planets are very common around other stars.

New research following up on the Kepler discoveries shows that alien worlds, or exoplanets, can be divided into three groups -- terrestrials, gas giants, and mid-sized "gas dwarfs" -- based on how their host stars tend to fall into three distinct groups defined by their compositions.

"We were particularly interested in probing the planetary regime smaller than four times the size of Earth, because it includes three-fourths of the planets found by Kepler. That's where you'll find rocky worlds, which are the only kind that we would consider potentially habitable," says lead author Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics (CfA).

Buchhave presented his research today at a meeting of the American Astronomical Society.

Kepler finds exoplanets using the transit method, looking for a star that dims as a planet passes in front of it from our point of view. We can learn the planet's size from how much starlight it blocks. However, to determine the planet's composition we need to measure its mass, so its density can be calculated. A rocky planet will be much denser than a gas giant. Unfortunately, the smaller a planet, the harder it is to measure its mass, especially for the dim and distant stars examined by Kepler.

Buchhave and his colleagues took a different approach. They measured the amount of elements heavier than hydrogen and helium, which astronomers collectively call metals, in stars with exoplanet candidates. Since a star and its planets form from the same disk of material, the metallicity of a star reflects the composition of the protoplanetary disk.

The team took follow-up spectra of more than 400 stars hosting over 600 exoplanets. Then, they conducted a statistical test to see if the sizes of the planets fell into natural groups, along with the stellar metallicities.

They found two clear dividing lines -- one at a size 1.7 times as large as Earth and the other at a size 3.9 times larger than Earth. They infer that these boundaries also mark changes in composition. Planets smaller than 1.7 Earths are likely to be completely rocky, while those larger than 3.9 Earths are probably gas giants.

Planets between 1.7 and 3.9 times the size of Earth were dubbed gas dwarfs since they have thick atmospheres of hydrogen and helium. The rocky cores of gas dwarfs formed early enough to accrete some gas, although they did not grow as large as gas giants like Jupiter.

In addition, Buchhave and his collaborators discovered that the size of the largest rocky world isn't fixed. The farther a planet is from its star, the larger it can grow before accumulating a thick atmosphere and turning into a gas dwarf. This suggests that some super-Earths can grow into true monsters.

Finally, the team found that stars with small, terrestrial worlds tended to have metallicities similar to the Sun. Stars hosting gas dwarfs tended to be slightly more metal-rich. Stars with gas giants contained the most metals -- about 50 percent more than our Sun.

Read more at Science Daily

Strange New World Discovered: The 'Mega Earth'

Meet “mega-Earth,” a souped-up, all-solid planet that, according to theory, should not exist.

First spotted by NASA’s Kepler space telescope, the planet is about 2.3 times larger than Earth. Computer models show planets that big would be more like Neptune or the other gas planets of the outer solar system since they would have the gravitational heft to collect vast amounts of hydrogen and helium from their primordial cradles.

But follow-up observations of the planet, designated as Kepler-10c, show it has 17 times as much mass as Earth, meaning it must be filled with rock and other materials much heavier than hydrogen and helium.

“Kepler-10c is a big problem for the theory,” astronomer Dimitar Sasselov, director of the Harvard Origins of Life Initiative, told Discovery News. “It’s nice that we have a solid piece of evidence and measurements for it because that gives motivations to the theorists to improve the theory,” he said.

Scientists aren’t sure how mega-Earths, or their diminutive cousins, super-Earths, form, nor why our solar system has nothing in between the largest rocky planet, Earth, and the smallest gas giant, Neptune.

“There was enough material for a super-Earth or mega-Earth to form, so it’s not that the building materials weren’t there. We think that the reason it didn’t form -- or that in some planetary systems they don’t form -- is because the conditions don’t work out to form a bigger rocky planet than the Earth. They don’t get their act together on time and you end up with a bunch of small planets which are rocky and a completely different bunch of bigger planets, which are the gas planets,” Sasselov said.

“We see that the rest of the galaxy’s planetary systems have members in all different shapes and forms,” he added “But how unique is the solar system, we don’t know the answer to this yet.”

Read more at Discovery News

Red Dwarfs Could Sterilize Alien Worlds of Life

Red dwarf stars -- the most common stars in the galaxy -- bathe planets in their habitable zones with potentially deadly stellar winds, a finding that could have significant impacts on the prevalence of life beyond Earth, new research shows.

About 70 percent of stars are red dwarfs, or M-type stars, which are cooler and smaller than the sun. Any red dwarf planets suitable for liquid water, therefore, would have to orbit much closer to their parent star than Earth circles the sun.

That presents a problem for life -- at least life as we know it on Earth, says physicist Ofer Cohen, with the Harvard-Smithsonian Center for Astrophysics.

Cohen and colleagues used a computer model based on data from the sun’s solar wind -- a continuous stream of charged particles that permeates and defines the solar system –- to estimate the space environment around red dwarf stars.

“We find that the conditions are very extreme. If you move planets very close to the star, the force of this flow is very, very strong. Essentially it can strip the atmosphere of the planet unless the planet has a strong magnetic field or a thick atmosphere to start with,” Cohen told Discovery News.

To be the right surface temperature for water, a planet would need to be about 9.3 million to 18.6 million miles from its host red dwarf star. By comparison, airless Mercury is about 36 million miles from the sun. Earth is about 93 million miles away.

Solar radiation pressure, however, is about the same for sun-like stars and red dwarfs.

“You have stronger flow as you move closer and closer,” Cohen said. “It applies a stripping force on the planet. It’s mostly due to the fact that they are close, it depends less on the star itself.”

Red dwarf stars also are more magnetically active than the sun and emit more X-ray and ultraviolet light, factors that can heighten space weather impacts, Cohen added.

“Planets may lose their atmospheres much faster,” due to star flares and other solar-type storms, Cohen said.

Read more at Discovery News

Subtle change in DNA, protein levels determines blond or brunette tresses, study finds

A molecule critical to stem cell function plays a major role in determining human hair color, according to a study from the Stanford University School of Medicine.

The study describes for the first time the molecular basis for one of our most noticeable traits. It also outlines how tiny DNA changes can reverberate through our genome in ways that may affect evolution, migration and even human history.

"We've been trying to track down the genetic and molecular basis of naturally occurring traits -- such as hair and skin pigmentation -- in fish and humans to get insight into the general principles by which traits evolve," said David Kingsley, PhD, professor of developmental biology. "Now we find that one of the most crucial signaling molecules in mammalian development also affects hair color."

Kingsley, who is also a Howard Hughes Medical Institute investigator, is the senior author of the study, which will be published online June 1 in Nature Genetics. Research specialist Catherine Guenther, PhD, is the lead author.

The researchers found that the blond hair commonly seen in Northern Europeans is caused by a single change in the DNA that regulates the expression of a gene that encodes a protein called KITLG, also known as stem cell factor. This change affects how much KITLG is expressed in the hair follicles without changing how it's expressed in the rest of the body. Introducing the change into normally brown-haired laboratory mice yields an animal with a decidedly lighter coat -- not quite Norma Jeane to Marilyn Monroe, but significant nonetheless.

The study shows that even small, tissue-specific changes in the expression of genes can have noticeable morphological effects. It also emphasizes how difficult it can be to clearly connect specific DNA changes with particular clinical or phenotypic outcomes. In this case, the change is subtle: A single nucleotide called an adenine is replaced by another called a guanine on human chromosome 12. The change occurs over 350,000 nucleotides away from the KITLG gene and only alters the amount of gene expression about 20 percent -- a relatively tiny blip on a biological scale more often assessed in terms of gene expression being 100 percent "on" or "off."

"What we're seeing is that this regulatory region exercises exquisite control over where, and how much, KITLG expression occurs," said Kingsley. "In this case, it controls hair color. In another situation -- perhaps under the influence of a different regulatory region -- it probably controls stem cell division. Dialing up and down the expression of an essential growth factor in this manner could be a common mechanism that underlies many different traits."

Kingsley is known for his studies of the evolution of a tiny fish called the threespine stickleback. The stickleback adapts quickly to changes in its environment. It becomes darker in murky lakes, and develops modified spine, fin and armor structures in response to different types of predators. Kingsley's research has shown that these adaptive changes are often driven by changes in the regulatory regions that surround and control gene expression, rather than within the coding regions of the genes themselves.

In the current study, the researchers had a couple of clues as to which regulatory regions might be important in hair color. One was the fact that the adenine-to-guanine nucleotide change had been previously associated with blond hair color in Northern Europeans in genome-wide association studies. The second was the existence in laboratory mice of a large mutation called an inversion that affects several million nucleotides near the KITLG gene. Mice with two copies of this mutation (one on each chromosome) are white; those with just one copy are significantly lighter than wild-type mice. But it wasn't known exactly how either of these changes affects hair pigment.

The researchers began by confirming that the mouse mutation occurs in a region that is similar, or homologous, to where the single nucleotide change occurs in humans. They also showed that the skin of mice with one copy of the mutation expressed about 60 percent the amount of KITLG as the skin of mice without the mutation.

Further study showed that the region of human DNA that contained the single nucleotide change associated with blondness specifically affected the expression of KITLG only in hair follicles.

Finally, the researchers replaced the mouse mutation with human sequences with and without the blond-associated nucleotide change. Those with the guanine tied to blond hair in humans did in fact have significantly lighter hair.

Read more at Science Daily

How to erase a memory –- and restore it

Researchers at the University of California, San Diego School of Medicine have erased and reactivated memories in rats, profoundly altering the animals' reaction to past events.

The study, published in the June 1 advanced online issue of the journal Nature, is the first to show the ability to selectively remove a memory and predictably reactivate it by stimulating nerves in the brain at frequencies that are known to weaken and strengthen the connections between nerve cells, called synapses.

"We can form a memory, erase that memory and we can reactivate it, at will, by applying a stimulus that selectively strengthens or weakens synaptic connections," said Roberto Malinow, MD, PhD, professor of neurosciences and senior author of the study.

Scientists optically stimulated a group of nerves in a rat's brain that had been genetically modified to make them sensitive to light, and simultaneously delivered an electrical shock to the animal's foot. The rats soon learned to associate the optical nerve stimulation with pain and displayed fear behaviors when these nerves were stimulated.

Analyses showed chemical changes within the optically stimulated nerve synapses, indicative of synaptic strengthening.

In the next stage of the experiment, the research team demonstrated the ability to weaken this circuitry by stimulating the same nerves with a memory-erasing, low-frequency train of optical pulses. These rats subsequently no longer responded to the original nerve stimulation with fear, suggesting the pain-association memory had been erased.

In what may be the study's most startlingly discovery, scientists found they could re-activate the lost memory by re-stimulating the same nerves with a memory-forming, high-frequency train of optical pulses. These re-conditioned rats once again responded to the original stimulation with fear, even though they had not had their feet re-shocked.

"We can cause an animal to have fear and then not have fear and then to have fear again by stimulating the nerves at frequencies that strengthen or weaken the synapses," said Sadegh Nabavi, a postdoctoral researcher in the Malinow lab and the study's lead author.

Read more at Science Daily