A new carnivorous dinosaur species named Dracoraptor hanigani uncovered in the south of Wales is possibly the oldest known Jurassic dinosaur from the UK, according to a study published January 20, 2016 in the open-access journal PLOS ONE by David Martill from the University of Portsmouth, England, and colleagues from National Museum Wales and University of Manchester.
The authors of this study that analyzed the dinosaur skull and bones, discovered in 2014 on a beach near Penarth, Wales, conclude it is a new species that they have named Dracoraptor hanigani. The name Dracoraptor means 'dragon robber.' Draco, meaning dragon, is the national symbol of Wales. The species name honors Nick and Rob Hanigan, who discovered the fossil.
From their analysis, the researchers believe this dinosaur was meat-eating, from the theropod group. They also suggested that it may have been a juvenile animal, as most of its bones were not yet fully formed or fused. Compared to its distant relative the T. rex, it appears to be a small, agile animal, probably only about 70 cm tall and about 200 cm long, with a long tail, likely to help it balance. It lived at the beginning of the Jurassic Period (201 million years ago), at the time when south Wales was a coastal region like it is today. However, at the time, the climate was much warmer, and dinosaurs were just starting to diversify. The new specimen represents the most complete theropod from Wales, and may possibly represent one of the oldest known Jurassic dinosaurs in the UK or even in the world.
Co-author Mr. Vidovic adds, "The Triassic-Jurassic extinction event is often credited for the later success of dinosaurs through the Jurassic and Cretaceous, but previously we knew very little about dinosaurs at the start of this diversification and rise to dominance. Now we have Dracoraptor, a relatively complete two meter long juvenile theropod from the very earliest days of the Jurassic in Wales."
From Science Daily
Jan 23, 2016
Beetle-inspired discovery could reduce frost's costly sting
In a discovery that may lead to ways to prevent frost on airplane parts, condenser coils, and even windshields, a team of researchers led by Virginia Tech has used chemical micropatterns to control the growth of frost caused by condensation.
Writing in the Jan. 22, 2016 edition of Scientific Reports, an online journal from the publishers of Nature, the researchers describe how they used photolithography to pattern chemical arrays that attract water over top of a surface that repels water, thereby controlling or preventing the spread of frost.
The inspiration for the work came from an unlikely source -- the Namib Desert Beetle, which makes headlines because it lives in one of the hottest places in the world, yet it still collects airborne water.
The insect has a bumpy shell and the tips of the bumps attract moisture to form drops, but the sides are smooth and repel water, creating channels that lead directly to the beetle's mouth.
"I appreciate the irony of how an insect that lives in a hot, dry desert inspired us to make a discovery about frost," said Jonathan Boreyko, an assistant professor of Biomedical Engineering and Mechanics in the Virginia Tech College of Engineering. "The main takeaway from the Desert Beetle is we can control where dew drops grow."
Working at the Oak Ridge National Laboratory, the researchers developed their beetle-inspired, frost-controlling chemical pattern on a surface only about the size of a centimeter, but they believe the area can be scaled up to large surface areas with thirsty, hydrophilic patterns overtop of a hydrophobic, or water-repellant, surface.
"We made a single dry zone around a piece of ice," Boreyko said. "Dew drops preferentially grow on the array of hydrophilic dots. When the dots are spaced far enough apart and one of the drops freezes into ice, the ice is no longer able to spread frost to the neighboring drops because they are too far away. Instead, the drops actually evaporate completely, creating a dry zone around the ice."
Creating frost-free zones on larger surfaces could have a variety of applications -- consider the water that forms and freezes on heat pump coils or the deicing with harsh chemicals that has to take place on wind turbines or airplane wings.
"Keeping things dry requires huge energy expenditures," said C. Patrick Collier, a research scientist at the Nanofabrication Research Laboratory Center for Nanophase Materials Sciences at Oak Ridge National Laboratory and a co-author of the study. "That's why we are paying more attention to ways to control water condensation and freezing. It could result in huge cost savings."
The journey of frost across a surface begins with a single, frozen dew drop, the researchers said.
"The twist is how ice bridges grow," Boreyko said. "Ice harvests water from dew drops and this causes ice bridges to propagate frost across the droplets on the surface. Only a single droplet has to freeze to get this chain reaction started."
By controlling spacing of the condensation, the researchers were able to control the speed frost grows across surfaces, or completely prevent frost.
Read more at Science Daily
Writing in the Jan. 22, 2016 edition of Scientific Reports, an online journal from the publishers of Nature, the researchers describe how they used photolithography to pattern chemical arrays that attract water over top of a surface that repels water, thereby controlling or preventing the spread of frost.
The inspiration for the work came from an unlikely source -- the Namib Desert Beetle, which makes headlines because it lives in one of the hottest places in the world, yet it still collects airborne water.
The insect has a bumpy shell and the tips of the bumps attract moisture to form drops, but the sides are smooth and repel water, creating channels that lead directly to the beetle's mouth.
"I appreciate the irony of how an insect that lives in a hot, dry desert inspired us to make a discovery about frost," said Jonathan Boreyko, an assistant professor of Biomedical Engineering and Mechanics in the Virginia Tech College of Engineering. "The main takeaway from the Desert Beetle is we can control where dew drops grow."
Working at the Oak Ridge National Laboratory, the researchers developed their beetle-inspired, frost-controlling chemical pattern on a surface only about the size of a centimeter, but they believe the area can be scaled up to large surface areas with thirsty, hydrophilic patterns overtop of a hydrophobic, or water-repellant, surface.
"We made a single dry zone around a piece of ice," Boreyko said. "Dew drops preferentially grow on the array of hydrophilic dots. When the dots are spaced far enough apart and one of the drops freezes into ice, the ice is no longer able to spread frost to the neighboring drops because they are too far away. Instead, the drops actually evaporate completely, creating a dry zone around the ice."
Creating frost-free zones on larger surfaces could have a variety of applications -- consider the water that forms and freezes on heat pump coils or the deicing with harsh chemicals that has to take place on wind turbines or airplane wings.
"Keeping things dry requires huge energy expenditures," said C. Patrick Collier, a research scientist at the Nanofabrication Research Laboratory Center for Nanophase Materials Sciences at Oak Ridge National Laboratory and a co-author of the study. "That's why we are paying more attention to ways to control water condensation and freezing. It could result in huge cost savings."
The journey of frost across a surface begins with a single, frozen dew drop, the researchers said.
"The twist is how ice bridges grow," Boreyko said. "Ice harvests water from dew drops and this causes ice bridges to propagate frost across the droplets on the surface. Only a single droplet has to freeze to get this chain reaction started."
By controlling spacing of the condensation, the researchers were able to control the speed frost grows across surfaces, or completely prevent frost.
Read more at Science Daily
Newly discovered star offers opportunity to explore origins of first stars sprung to life in early universe
A team of researchers has observed the brightest ultra metal-poor star ever discovered.
The star is a rare relic from the Milky Way's formative years. As such, it offers astronomers a precious opportunity to explore the origin of the first stars that sprung to life within our galaxy and the universe.
A Brazilian-American team including Vinicius Placco, a research assistant professor at the University of Notre Dame and a member of JINA-CEE (Joint Institute for Nuclear Astrophysics -- Center for the Evolution of the Elements), and led by Jorge Meléndez from the University of São Paulo used two of European Southern Observatory's telescopes in Chile to discover this star, named 2MASS J18082002-5104378.
The star was spotted in 2014 using ESO's New Technology Telescope. Follow-up observations using ESO's Very Large Telescope discovered that, unlike younger stars such as the sun, this star shows an unusually low abundance of what astronomers call metals -- elements heavier than hydrogen and helium. It is so devoid of these elements that it is known as an ultra metal-poor star.
Although thought to be ubiquitous in the early universe, metal-poor stars are now a rare sight within both the Milky Way and other nearby galaxies. Metals are formed during nuclear fusion within stars, and are spread throughout the interstellar medium when some of these stars grow old and explode. Subsequent generations of stars therefore form from increasingly metal-rich material. Metal-poor stars, however, formed from the unpolluted environment that existed shortly after the Big Bang. Exploring stars such as 2MASS J18082002-5104378 may unlock secrets about their formation, and show what the universe was like at its very beginning.
From Science Daily
The star is a rare relic from the Milky Way's formative years. As such, it offers astronomers a precious opportunity to explore the origin of the first stars that sprung to life within our galaxy and the universe.
A Brazilian-American team including Vinicius Placco, a research assistant professor at the University of Notre Dame and a member of JINA-CEE (Joint Institute for Nuclear Astrophysics -- Center for the Evolution of the Elements), and led by Jorge Meléndez from the University of São Paulo used two of European Southern Observatory's telescopes in Chile to discover this star, named 2MASS J18082002-5104378.
The star was spotted in 2014 using ESO's New Technology Telescope. Follow-up observations using ESO's Very Large Telescope discovered that, unlike younger stars such as the sun, this star shows an unusually low abundance of what astronomers call metals -- elements heavier than hydrogen and helium. It is so devoid of these elements that it is known as an ultra metal-poor star.
Although thought to be ubiquitous in the early universe, metal-poor stars are now a rare sight within both the Milky Way and other nearby galaxies. Metals are formed during nuclear fusion within stars, and are spread throughout the interstellar medium when some of these stars grow old and explode. Subsequent generations of stars therefore form from increasingly metal-rich material. Metal-poor stars, however, formed from the unpolluted environment that existed shortly after the Big Bang. Exploring stars such as 2MASS J18082002-5104378 may unlock secrets about their formation, and show what the universe was like at its very beginning.
From Science Daily
Jan 22, 2016
Toxic Red Tide Might Be in Your Fish Tank
For people who live in coastal areas, harmful algal blooms, or HABs — sometimes called red tides, because they can turn seawater a deep red — are an increasingly frequent threat, thanks to climate change. HABs produce toxins that cause mass fish kills and make shellfish risky to eat. In rare instances, they can cause life-threatening respiratory illnesses in humans, and also make the surrounding air more difficult to breathe.
But as it turns out, you may be at risk of exposure to the algae that cause red tides even if you don’t go anywhere near the beach. The possible point of exposure is a home aquarium.
In a study just published in the journal Environmental Science & Technology, Italian researchers detected the presence of high levels of the palytoxin and hydroxypalytoxin, two chemicals secreted by HABs, in a saltwater aquarium found in a home where an entire Dutch family of four suffered respiratory distress, fevers, nausea and flu-like symptoms. The toxins were found in soft coral and seawater from the aquarium, according to the study.
The presence of those hazardous chemicals provides an explanation for other anecdotal reports of aquarium owners becoming ill, according to the study. The illnesses occurred after the owners used hot water to clean their tanks. Apparently, hot water making contact with aquarium rocks creates steam that releases the toxins into the room’s air, where they can be inhaled by unwary occupants.
If there’s some good news here, it’s that the hazard can now be identified. Lead researcher Carmela Dell’Aversano and colleagues developed a test that can quickly determine if the toxins are present in an aquarium.
From Discovery News
But as it turns out, you may be at risk of exposure to the algae that cause red tides even if you don’t go anywhere near the beach. The possible point of exposure is a home aquarium.
In a study just published in the journal Environmental Science & Technology, Italian researchers detected the presence of high levels of the palytoxin and hydroxypalytoxin, two chemicals secreted by HABs, in a saltwater aquarium found in a home where an entire Dutch family of four suffered respiratory distress, fevers, nausea and flu-like symptoms. The toxins were found in soft coral and seawater from the aquarium, according to the study.
The presence of those hazardous chemicals provides an explanation for other anecdotal reports of aquarium owners becoming ill, according to the study. The illnesses occurred after the owners used hot water to clean their tanks. Apparently, hot water making contact with aquarium rocks creates steam that releases the toxins into the room’s air, where they can be inhaled by unwary occupants.
If there’s some good news here, it’s that the hazard can now be identified. Lead researcher Carmela Dell’Aversano and colleagues developed a test that can quickly determine if the toxins are present in an aquarium.
From Discovery News
Hundreds of Turtles Found Dead on Beach in India
The Times Of India reports that more than 300 olive ridley turtles have been found dead on Puri Beach in eastern India.
The publication notes that the turtles do on occasion wash up at this time of year, but a mass beaching of this size has people searching for answers.
While the cause of the mass death is not yet certain, initial theories suggest the animals may have been hit by fishing trawlers, the Times reporting that two ships have been seized in the area for illegal fishing.
Olive Ridley turtles are considered the most abundant sea turtle species, according to the National Oceanographic and Atmospheric Administration. Their range includes the tropical portions of the Atlantic, Pacific, and Indian oceans. Adults can weight about 100 pounds and reach about 2.5 feet long.
When nesting, the turtles gather just off shore and then head for the beach together, in a mass event known as an “arribada” (Spanish for arrival). Females nest once per year and make two trips to deposit up to 100 eggs per visit.
The trawlers were seized because they were in violation of a fishing ban period put in place to accommodate the turtles' nesting season.
From Discovery News
The publication notes that the turtles do on occasion wash up at this time of year, but a mass beaching of this size has people searching for answers.
While the cause of the mass death is not yet certain, initial theories suggest the animals may have been hit by fishing trawlers, the Times reporting that two ships have been seized in the area for illegal fishing.
Olive Ridley turtles are considered the most abundant sea turtle species, according to the National Oceanographic and Atmospheric Administration. Their range includes the tropical portions of the Atlantic, Pacific, and Indian oceans. Adults can weight about 100 pounds and reach about 2.5 feet long.
When nesting, the turtles gather just off shore and then head for the beach together, in a mass event known as an “arribada” (Spanish for arrival). Females nest once per year and make two trips to deposit up to 100 eggs per visit.
The trawlers were seized because they were in violation of a fishing ban period put in place to accommodate the turtles' nesting season.
From Discovery News
Rodents Show Empathy for Loved Ones in Pain
Dogs, dolphins and elephants are known to show empathy when a loved one is in pain, and now researchers have found the first consoling behavior in a rodent, known as the prairie vole.
Researchers say the findings, published Thursday in the US journal Science, could help scientists better understand human disorders such as autism and schizophrenia, in which a person’s ability to sense the emotions of others is disrupted.
The secret to empathetic behavior lies in the hormone oxytocin, which promotes maternal bonding and feelings of love among humans, too.
Scientists at the Yerkes National Primate Research Center at Emory University created an experiment in which they isolated prairie voles — dark rodents which mate in long-term monogamous pairs and raise their offspring together — from others they knew.
Then they gave one prairie voles a series of mild shocks before returning it to its loved one.
Once reunited, the unaffected rodents swiftly began to lick and groom the fur of the animals that were in distress after the shocks.
They “licked the stressed voles sooner and for longer durations, compared to a control scenario where individuals were separated but neither was exposed to a stressor,” said a statement from Emory University.
Consoling behavior was also not seen in prairie voles that were unfamiliar with each other before being separated.
Knowing that in the human brain, the receptor for oxytocin — also known as the love hormone — is associated with empathy, researchers decided to block this neurotransmitter in the brains of some of the animals.
They found that blocking oxytocin caused the animals to stop consoling each other.
“Many complex human traits have their roots in fundamental brain processes that are shared among many other species,” said co-author Larry Young, director of the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory University.
Read more at Discovery News
Researchers say the findings, published Thursday in the US journal Science, could help scientists better understand human disorders such as autism and schizophrenia, in which a person’s ability to sense the emotions of others is disrupted.
The secret to empathetic behavior lies in the hormone oxytocin, which promotes maternal bonding and feelings of love among humans, too.
Scientists at the Yerkes National Primate Research Center at Emory University created an experiment in which they isolated prairie voles — dark rodents which mate in long-term monogamous pairs and raise their offspring together — from others they knew.
Then they gave one prairie voles a series of mild shocks before returning it to its loved one.
Once reunited, the unaffected rodents swiftly began to lick and groom the fur of the animals that were in distress after the shocks.
They “licked the stressed voles sooner and for longer durations, compared to a control scenario where individuals were separated but neither was exposed to a stressor,” said a statement from Emory University.
Consoling behavior was also not seen in prairie voles that were unfamiliar with each other before being separated.
Knowing that in the human brain, the receptor for oxytocin — also known as the love hormone — is associated with empathy, researchers decided to block this neurotransmitter in the brains of some of the animals.
They found that blocking oxytocin caused the animals to stop consoling each other.
“Many complex human traits have their roots in fundamental brain processes that are shared among many other species,” said co-author Larry Young, director of the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory University.
Read more at Discovery News
Frozen Animal Brought Back to Life After 30 Years
An animal that had been frozen for 30 years has been revived by scientists — and it then successfully reproduced.
The animal in question was a species of tardigrade, a microscopic creature sometimes referred to as a “water bear” that is perhaps the hardiest lifeform on Earth. There are over1,000 known species, all of which have eight legs and measure between 0.5 and 1.2 mm in length, and they are found more or less everywhere.
As Brian Resnick wrote recently for Vox: “Pick up a piece of moss, and you’ll find tardigrades. In the soil: tardigrades. The ocean: You get it. They live on every continent, in every climate, and in every latitude. Their extreme resilience has allowed them to conquer the entire planet.”
This resilience comes from tardigrades’ ability, when conditions are especially harsh, to enter a state known cryptobiosis (or anabiosis). They achieve this by expelling 95 percent or more of their water, creating proteins and sugars to protect their cells, massively reducing or even suspending their metabolism, and tucking in their heads and legs to form a pill-shaped “tun.”
In tun form, tardigrades can withstand conditions from boiling water to absolute zero, and pressures six times greater than those found in the deepest part of the ocean. In 2007, the European Space Agency even launched a payload of tardigrades in tun form into space; retrieved 10 days later after the satellite returned to Earth, some of the tardigrades came back to life upon rehydration and even went on to reproduce, the first animals to survive the vacuum of space.
Even by tardigrade standards, however, the most recent example of survival skills is impressive. The water bears in question were in a moss sample that was collected in November 1983 during a Japanese research expedition to Antarctica. The moss was stored at -20 degrees C after collection. In May 2014, researchers began to thaw out the moss, teased it apart with tweezers and found two tardigrades — which they delightfully dubbed Sleeping Beauty 1 and 2 (or SB-1 and SB-2 to their friends) — in tun form.
Recovery was steady but slow, the researchers write in the journal Cryobiology: “SB-1 first showed slight movement in its 4th pair of legs on the first day after rehydration. This progressed to twisting of the body from day 5 along with movement in its 1st and 2nd pairs of legs, but the movements remained slow. After starting to attempt to lift itself on day 6, SB-1 started to slowly crawl on the agar surface of the culture well on day 9, and started to eat the algal food provided the culture plate on day 13.”
Read more at Discovery News
The animal in question was a species of tardigrade, a microscopic creature sometimes referred to as a “water bear” that is perhaps the hardiest lifeform on Earth. There are over1,000 known species, all of which have eight legs and measure between 0.5 and 1.2 mm in length, and they are found more or less everywhere.
As Brian Resnick wrote recently for Vox: “Pick up a piece of moss, and you’ll find tardigrades. In the soil: tardigrades. The ocean: You get it. They live on every continent, in every climate, and in every latitude. Their extreme resilience has allowed them to conquer the entire planet.”
This resilience comes from tardigrades’ ability, when conditions are especially harsh, to enter a state known cryptobiosis (or anabiosis). They achieve this by expelling 95 percent or more of their water, creating proteins and sugars to protect their cells, massively reducing or even suspending their metabolism, and tucking in their heads and legs to form a pill-shaped “tun.”
In tun form, tardigrades can withstand conditions from boiling water to absolute zero, and pressures six times greater than those found in the deepest part of the ocean. In 2007, the European Space Agency even launched a payload of tardigrades in tun form into space; retrieved 10 days later after the satellite returned to Earth, some of the tardigrades came back to life upon rehydration and even went on to reproduce, the first animals to survive the vacuum of space.
Even by tardigrade standards, however, the most recent example of survival skills is impressive. The water bears in question were in a moss sample that was collected in November 1983 during a Japanese research expedition to Antarctica. The moss was stored at -20 degrees C after collection. In May 2014, researchers began to thaw out the moss, teased it apart with tweezers and found two tardigrades — which they delightfully dubbed Sleeping Beauty 1 and 2 (or SB-1 and SB-2 to their friends) — in tun form.
Recovery was steady but slow, the researchers write in the journal Cryobiology: “SB-1 first showed slight movement in its 4th pair of legs on the first day after rehydration. This progressed to twisting of the body from day 5 along with movement in its 1st and 2nd pairs of legs, but the movements remained slow. After starting to attempt to lift itself on day 6, SB-1 started to slowly crawl on the agar surface of the culture well on day 9, and started to eat the algal food provided the culture plate on day 13.”
Read more at Discovery News
The Voracious Fish That Looks Like a Pug and Stings Like a Bee
The only way a stargazer could turn its frown upside down is if you rotated this picture 180 degrees. |
It’s a kind of terror a fish known as the stargazer embodies its entire life. It may not be worrying about a visit from Child Protective Services, but it does have to worry about eating. The bulging eyes and frowny mouth that make it look like an aquatic pug are brilliant adaptations for an ambush predator. And even beyond its … singular looks, this is one of the sea’s most remarkable fishes—it’s venomous and it shocks like an electric eel.
Unless you’ve got a coral reef to duck into, the bottom of the ocean is a place of constant peril. Death comes from above, sideways, and, with the strategy of the 50 or so species of stargazer thrown in the mix, from below. To get a jump on their prey, the fish burrow into the sand, exposing only their mouths and bug-eyes. This has an added bonus of hiding the stargazers from their own enemies swimming above.
So the stargazer is buried there, biding its time, probably thinking about eating and stuff. Some species even utilize a specially-shaped piece of flesh on the inside of their mouths, which acts like a lure to fish and crustaceans hunting on the seafloor. “They’re able to stick this out of the mouth when they’re burrowed, resembling a segmented worm to draw the attention of other fish,” says systemicist Martin Gomon of Australia’s Museum Victoria. (The anglerfishes utilize a similar ruse, only their lures are actually modified dorsal spines. Also, their sex is kinky.)
Curious fish expecting an easy meal instead get a healthy dose of death. All the stargazer has to do is rapidly open its gaping maw, and the resulting vacuum drags the prey to its doom. It’s so effective, the predator has no need for nasty, big, pointy teeth to snag its prey—its chompers are relatively tiny.
Watch this on The Scene.
But this lifestyle comes with unique challenges. For one, the stargazer has to worry about the water flowing out of its buried gills kicking up sand. If potential prey see the substrate bubbling up around the predator, the ruse is up. So the stargazer has a clever adaptation: Its gill covers are fringed with finger-like projections that may better disperse the water coming out, as opposed to firing it out as a solid jet.
Its mouth, too, has frills around the edges to keep sand from falling in as the fish gulps water. And it’s not just that the stargazer wants to avoid choking to death here. Sand is, of course, super abrasive. “What you want to do is minimize the amount of sand that damages the gills over time,” says Gomon.
While the stargazer’s camouflage may be top-notch, it isn’t perfect. So the fish deploys additional countermeasures in the event of an oh-bother-I’m-in-another-animal’s-mouth kind of situation. First, it has a venomous spine just above the base of its pectoral fins (those would be the ones on the fish’s sides). While its venom is still poorly studied, it’s apparently got some kick, considering stargazers have dropped a handful of humans dead.
Some stargazer species also deploy a second countermeasure: a specialized organ behind their eyes that fires out a blast of electricity. Like an electric eel, stargazers can zap their enemies, though they use it for defense, not hunting. And the stargazers’ blast is far weaker than an electric eel’s—50 volts compared to 600—but the jolt may just be enough to startle a predator into turning the fish loose.
Its mouth, too, has frills around the edges to keep sand from falling in as the fish gulps water. And it’s not just that the stargazer wants to avoid choking to death here. Sand is, of course, super abrasive. “What you want to do is minimize the amount of sand that damages the gills over time,” says Gomon.
While the stargazer’s camouflage may be top-notch, it isn’t perfect. So the fish deploys additional countermeasures in the event of an oh-bother-I’m-in-another-animal’s-mouth kind of situation. First, it has a venomous spine just above the base of its pectoral fins (those would be the ones on the fish’s sides). While its venom is still poorly studied, it’s apparently got some kick, considering stargazers have dropped a handful of humans dead.
Some stargazer species also deploy a second countermeasure: a specialized organ behind their eyes that fires out a blast of electricity. Like an electric eel, stargazers can zap their enemies, though they use it for defense, not hunting. And the stargazers’ blast is far weaker than an electric eel’s—50 volts compared to 600—but the jolt may just be enough to startle a predator into turning the fish loose.
With any luck, that fake worm will attract a fish to its doom. So when a stargazer does the worm, it’s a bit more literal than for humans. |
Really, though, the stargazers’ strategy is to go unseen. Which makes one species, Pleuroscopus pseudodorsalis, particularly strange. Other stargazers will swim around as juveniles and settle into the sand once they reach about 2 inches long. But this species’ larva spends an inordinate chunk of its life braving a zone even more dangerous than the seafloor, the open ocean, only settling once it’s reached a foot long.
The juvenile’s body is uniquely suited for this lifestyle. Its eyes and mouth, for instance, aren’t angled as far back on the head, allowing it to better tackle prey straight ahead. “We thought it was a different species entirely,” says Gomon, “but the form of the body changes quite dramatically” between the juvenile and adult stages. Considering boats have brought the young up on baited lines, the fish appear to be active predators as juveniles.
But even though it’s removed from the relative safety of the seafloor, the juvenile is far from conspicuous, having evolved its own form of clever camouflage. The top half of its body is a dark blue, while its underside is paler—the same kind of countershading, as it’s known, that the great white shark deploys. Predators watching from above will have a harder time picking the stargazer out from the dark background of the water below, while predators watching from below will have a harder time picking it out from the sunlight trickling down from the surface.
The juvenile’s body is uniquely suited for this lifestyle. Its eyes and mouth, for instance, aren’t angled as far back on the head, allowing it to better tackle prey straight ahead. “We thought it was a different species entirely,” says Gomon, “but the form of the body changes quite dramatically” between the juvenile and adult stages. Considering boats have brought the young up on baited lines, the fish appear to be active predators as juveniles.
But even though it’s removed from the relative safety of the seafloor, the juvenile is far from conspicuous, having evolved its own form of clever camouflage. The top half of its body is a dark blue, while its underside is paler—the same kind of countershading, as it’s known, that the great white shark deploys. Predators watching from above will have a harder time picking the stargazer out from the dark background of the water below, while predators watching from below will have a harder time picking it out from the sunlight trickling down from the surface.
Read more at Wired Science
Jan 21, 2016
Prehistoric Massacre Hints at Hunter-Gatherer War
Skeletons unearthed in Kenya may be the oldest known evidence of human warfare, according to a new study.
The skeletons of 27 people who died about 10,000 years ago bear marks of blunt force trauma and projectile wounds, the researchers said in the study. The victims included men, women and children.
“That scale of death — it can’t be an individual murder or homicide amongst families,” said study co-author Robert Foley, an anthropologist and archaeologist at the University of Cambridge in England. “It was a result of some intergroup conflict.”
The findings could help answer questions about the roots of war and human aggression, Foley said.
Warlike by nature or nurture?
Are humans noble savages, or is the life of mankind nasty, brutish and short? For millennia, philosophers such as Jean-Jacques Rousseau and Thomas Hobbes have debated when and how war emerged in the human experience. Some anthropologists have argued that organized warfare didn’t emerge until complex societies with political hierarchies rose to power. Others claimed war emerged after the agricultural revolution, when people had finally amassed enough resources, such as livestock, worth fighting over. By that reckoning, true warfare — rather than squabbles between friends or family gone horribly wrong — would have been completely foreign to ancient hunter-gatherer groups.
But others note that humans’ closest living relatives, chimpanzees, organize violent attacks on lone chimps that stray into their territory. And modern-day hunter-gatherer communities, such as the Yanomami Amerindians in the remote Amazon jungle, regularly engage in violent and warlike skirmishes against neighboring villages.
Grisly find
Still, all of the evidence for warlike behavior in ancient people was indirect. More specifically, it was based on analogies with nonhumans, or on comparisons of modern hunter-gatherers, whose societies are threatened by habitat loss and colonialism, with ancient ancestors who did not face the same pressures, Foley said.
The new bones, which were uncovered at a site called Naturak, on the southwest edges of Lake Turkana in 2012, provide the first direct evidence of warfare in ancient hunter-gatherers. The discovery came as part of the larger In Africa project, led by Marta Mirazón Lahr, a researcher of human evolutionary biology at the University of Cambridge. The project aims to study the origin of Homo sapiens in East Africa.
Over the millennia, sediments from the lake provided the perfect conditions to preserve the bones, while falling lake levels have revealed the fossils over time, Foley said.
In this instance, the bones were once buried in a lagoon and were in the process of being revealed, with some partially visible at the surface. When the team dug deeper, they found a total of 27 skeletons, some nearly complete and some with just a few fragments, all dating to between 9,500 and 10,500 years ago, according to the paper, which was published today (Jan. 20) in the journal Nature.
“It’s not a cemetery; people haven’t been deliberately buried there,” Foley told Live Science. “They’ve fallen and been left where they died.”
Many of the bodies harbored blunt force trauma head wounds, as well as what look like arrow wounds to the head and neck. The murder weapons included projectiles, most likely bows and arrows, as well as wooden clubs, the researchers said. Men, women and children were killed; one woman was found with broken knees, lying on her side with her wrists in front, as if they were bound.
Intergroup conflict
The number of casualties rules out the notion of an interfamily feud, Foley said. More people from the group may have been killed, and still others may have escaped, which suggests the group was larger than the average hunter-gatherer group. (Most hunter-gatherer groups tend to hover around 25 to 30 people per encampment, Foley said.) And given the simple tools used to deal death, the attacking group was probably larger still, he added.
This idea suggests that the two warring groups were likely more settled than the average hunter-gatherer population, Foley said. That’s not surprising, as hunter-gatherers who tend to stay in one place for longer periods often live near lakes, where food is plentiful and unlikely to be depleted by long stays, he added.
Read more at Discovery News
The skeletons of 27 people who died about 10,000 years ago bear marks of blunt force trauma and projectile wounds, the researchers said in the study. The victims included men, women and children.
“That scale of death — it can’t be an individual murder or homicide amongst families,” said study co-author Robert Foley, an anthropologist and archaeologist at the University of Cambridge in England. “It was a result of some intergroup conflict.”
The findings could help answer questions about the roots of war and human aggression, Foley said.
Warlike by nature or nurture?
Are humans noble savages, or is the life of mankind nasty, brutish and short? For millennia, philosophers such as Jean-Jacques Rousseau and Thomas Hobbes have debated when and how war emerged in the human experience. Some anthropologists have argued that organized warfare didn’t emerge until complex societies with political hierarchies rose to power. Others claimed war emerged after the agricultural revolution, when people had finally amassed enough resources, such as livestock, worth fighting over. By that reckoning, true warfare — rather than squabbles between friends or family gone horribly wrong — would have been completely foreign to ancient hunter-gatherer groups.
But others note that humans’ closest living relatives, chimpanzees, organize violent attacks on lone chimps that stray into their territory. And modern-day hunter-gatherer communities, such as the Yanomami Amerindians in the remote Amazon jungle, regularly engage in violent and warlike skirmishes against neighboring villages.
Grisly find
Still, all of the evidence for warlike behavior in ancient people was indirect. More specifically, it was based on analogies with nonhumans, or on comparisons of modern hunter-gatherers, whose societies are threatened by habitat loss and colonialism, with ancient ancestors who did not face the same pressures, Foley said.
The new bones, which were uncovered at a site called Naturak, on the southwest edges of Lake Turkana in 2012, provide the first direct evidence of warfare in ancient hunter-gatherers. The discovery came as part of the larger In Africa project, led by Marta Mirazón Lahr, a researcher of human evolutionary biology at the University of Cambridge. The project aims to study the origin of Homo sapiens in East Africa.
Over the millennia, sediments from the lake provided the perfect conditions to preserve the bones, while falling lake levels have revealed the fossils over time, Foley said.
In this instance, the bones were once buried in a lagoon and were in the process of being revealed, with some partially visible at the surface. When the team dug deeper, they found a total of 27 skeletons, some nearly complete and some with just a few fragments, all dating to between 9,500 and 10,500 years ago, according to the paper, which was published today (Jan. 20) in the journal Nature.
“It’s not a cemetery; people haven’t been deliberately buried there,” Foley told Live Science. “They’ve fallen and been left where they died.”
Many of the bodies harbored blunt force trauma head wounds, as well as what look like arrow wounds to the head and neck. The murder weapons included projectiles, most likely bows and arrows, as well as wooden clubs, the researchers said. Men, women and children were killed; one woman was found with broken knees, lying on her side with her wrists in front, as if they were bound.
Intergroup conflict
The number of casualties rules out the notion of an interfamily feud, Foley said. More people from the group may have been killed, and still others may have escaped, which suggests the group was larger than the average hunter-gatherer group. (Most hunter-gatherer groups tend to hover around 25 to 30 people per encampment, Foley said.) And given the simple tools used to deal death, the attacking group was probably larger still, he added.
This idea suggests that the two warring groups were likely more settled than the average hunter-gatherer population, Foley said. That’s not surprising, as hunter-gatherers who tend to stay in one place for longer periods often live near lakes, where food is plentiful and unlikely to be depleted by long stays, he added.
Read more at Discovery News
Oldest Monument Gets Multi-Million Dollar Funding
Gobekli Tepe, an archaeological site in Turkey home to the world's oldest monument, will receive an investment of over $15 million over the next 20 years, it was announced Wednesday at The World Economic Forum in Davos, Switzerland.
Promoted by the Sahenk Initiative, the main sponsor, and the Turkish Ministry of Culture and Tourism, the project will support new excavations, build a world-class visitor center, and encourage tourists to visit a unique site which is believed to predate Stonehenge by 7,000 years and Egypt's pyramids by 7,500 years.
Standing at the top of a mountain ridge in the southeastern Anatolia region of Turkey, Gobekli Tepe comprises a series of mainly circular and oval-shaped structures which date from roughly 12,000 years ago.
The Neolithic site lies at the northern end of what the ancients called the Fertile Crescent, a part of Mesopotamia which was the location for the first city in history, the starting point of writing and the seed of civilization.
As the oldest known monument built by man, Gobekli Tepe goes beyond these firsts.
"It is our zero point in time," Ferit F. Sahenk, chairman of Turkey's Dogus Group, said.
Excavated since 1996 by German archaeologist Klaus Schmidt, the temple-like structures consist of T-shaped pillars finely carved with the images of wild animals. The tallest stones tower 16 feet and weigh between 7 and 10 tons.
Until his death in 2014, Schmidt was able to uncover six of these structures that were built on top of each other, in a time period that exceeds 1,000 years.
"As Gobekli Tepe is still being unearthed, our views about the history of settlement and civilization are ever-changing," Abdullah Kocapınar, cultural heritage and museums general director at the Turkish Ministry of Culture and Tourism, said.
He noted the site is crucial to understand the origins of civilization, in particular the formation of religious sites, the emergence of temple architecture, the birth of art, and the transformation of agriculture and livestock breeding.
Read more at Discovery News
Promoted by the Sahenk Initiative, the main sponsor, and the Turkish Ministry of Culture and Tourism, the project will support new excavations, build a world-class visitor center, and encourage tourists to visit a unique site which is believed to predate Stonehenge by 7,000 years and Egypt's pyramids by 7,500 years.
Standing at the top of a mountain ridge in the southeastern Anatolia region of Turkey, Gobekli Tepe comprises a series of mainly circular and oval-shaped structures which date from roughly 12,000 years ago.
The Neolithic site lies at the northern end of what the ancients called the Fertile Crescent, a part of Mesopotamia which was the location for the first city in history, the starting point of writing and the seed of civilization.
As the oldest known monument built by man, Gobekli Tepe goes beyond these firsts.
"It is our zero point in time," Ferit F. Sahenk, chairman of Turkey's Dogus Group, said.
Excavated since 1996 by German archaeologist Klaus Schmidt, the temple-like structures consist of T-shaped pillars finely carved with the images of wild animals. The tallest stones tower 16 feet and weigh between 7 and 10 tons.
Until his death in 2014, Schmidt was able to uncover six of these structures that were built on top of each other, in a time period that exceeds 1,000 years.
"As Gobekli Tepe is still being unearthed, our views about the history of settlement and civilization are ever-changing," Abdullah Kocapınar, cultural heritage and museums general director at the Turkish Ministry of Culture and Tourism, said.
He noted the site is crucial to understand the origins of civilization, in particular the formation of religious sites, the emergence of temple architecture, the birth of art, and the transformation of agriculture and livestock breeding.
Read more at Discovery News
What Does Climate Change Mean for Winter Storms?
With a massive East Coast snowstorm forecast for Friday, you may be wondering if the extreme conditions are a sign of climate change.
The answer is complicated. As National Center for Weather Administration director Thomas Karl recently explained, scientists now have the ability to show that some specific weather events — such as temperature extremes — are linked to increases in greenhouse gas emissions linked to human activities. But he said that it’s been more difficult to zero in and link other specific weather events to climate change, and this week’s big snowfall would fit into that category.
However, climate scientists say the long-term trend is for climate change to alter weather patterns and cause more severe snowstorms, even as winters become milder overall.
According to a 2014 federal report on climate change impacts in the U.S., since 1950 there’s evidence of an increase in both frequency and intensity of winter storms, even as overall annual snowfall has decreased over much of the nation.
You may also be wondering exactly how global warming leads to heavy snowstorms. According to NOAA’s Climate.gov website, the explanation seems to be that rising surface temperatures are causing increased evaporation, which in turn puts more water in the atmosphere.
NOAA says the boost in moisture and increased precipitation can be especially significant for coastal winter storms such as Nor’easters. You might remember that one of those buried Boston under heavy snow in mid-February of 2015.
As this 2014 Slate article by meteorologist Eric Holthaus explains, global warming also puts heat into the atmosphere that weakens the polar vortex, the swirl of high-altitude winds around the north that confines cold Arctic air. That, in turn, can allow cold air masses to slip southward, creating brutal cold weather.
Read more at Discovery News
The answer is complicated. As National Center for Weather Administration director Thomas Karl recently explained, scientists now have the ability to show that some specific weather events — such as temperature extremes — are linked to increases in greenhouse gas emissions linked to human activities. But he said that it’s been more difficult to zero in and link other specific weather events to climate change, and this week’s big snowfall would fit into that category.
However, climate scientists say the long-term trend is for climate change to alter weather patterns and cause more severe snowstorms, even as winters become milder overall.
According to a 2014 federal report on climate change impacts in the U.S., since 1950 there’s evidence of an increase in both frequency and intensity of winter storms, even as overall annual snowfall has decreased over much of the nation.
You may also be wondering exactly how global warming leads to heavy snowstorms. According to NOAA’s Climate.gov website, the explanation seems to be that rising surface temperatures are causing increased evaporation, which in turn puts more water in the atmosphere.
NOAA says the boost in moisture and increased precipitation can be especially significant for coastal winter storms such as Nor’easters. You might remember that one of those buried Boston under heavy snow in mid-February of 2015.
As this 2014 Slate article by meteorologist Eric Holthaus explains, global warming also puts heat into the atmosphere that weakens the polar vortex, the swirl of high-altitude winds around the north that confines cold Arctic air. That, in turn, can allow cold air masses to slip southward, creating brutal cold weather.
Read more at Discovery News
Some Plants Can Count
Venus flytraps and other carnivorous plants have the ability to count, according to a new study.
The discovery adds to the growing body of evidence that certain plants possess many animal-like abilities, even though they do not have brains. In this case, it’s now known that meat-eating plants can count up to at least five.
As for why this would be useful, project leader Rainer Hedrich of Universität Würzburg explained: “The carnivorous plant Dionaea muscipula, also known as Venus flytrap, can count how often it has been touched by an insect visiting its capture organ in order to trap and consume the animal prey.”
For the study, published in the journal Current Biology, Hedrich and his team used a machine to simulate an insect touching Venus flytraps. The machine emitted electric pulses to fool the plants into thinking an insect had just landed.
The researchers found that each numbered pulse/touch was associated with a particular response:
One: The plant’s trap enters a “ready to go” mode, noting the stimulation.
Two: The trap begins to close around the source of the stimulation.
Three: The trap closes tightly.
Four: The plant produces a hormone associated with the feeding process.
Five: Glands on the inner surface of the trap produce digestive enzymes and transporters that help to take up nutrients. At this point, if the stimulation were a real insect or other victim, it would be dinner.
Hedrich describes the numbered steps as a “deadly spiral of capture and disintegration.” The more the insect or other prey feels trapped, the more the plant closes in on the victim.
Read more at Discovery News
The discovery adds to the growing body of evidence that certain plants possess many animal-like abilities, even though they do not have brains. In this case, it’s now known that meat-eating plants can count up to at least five.
As for why this would be useful, project leader Rainer Hedrich of Universität Würzburg explained: “The carnivorous plant Dionaea muscipula, also known as Venus flytrap, can count how often it has been touched by an insect visiting its capture organ in order to trap and consume the animal prey.”
The researchers found that each numbered pulse/touch was associated with a particular response:
One: The plant’s trap enters a “ready to go” mode, noting the stimulation.
Two: The trap begins to close around the source of the stimulation.
Three: The trap closes tightly.
Four: The plant produces a hormone associated with the feeding process.
Five: Glands on the inner surface of the trap produce digestive enzymes and transporters that help to take up nutrients. At this point, if the stimulation were a real insect or other victim, it would be dinner.
Hedrich describes the numbered steps as a “deadly spiral of capture and disintegration.” The more the insect or other prey feels trapped, the more the plant closes in on the victim.
Read more at Discovery News
Bad Habits Hard-Wired in the Brain
Three weeks into 2016 and many resolutions are as stale as a bottle of champagne left open after a New Year’s party. Everyone has some kind of self-destructive behavior we’d be better off without, be it smoking or an unhealthy diet. Bad habits are hard to break, but why is that?
According to new research by Duke University researchers, our vices are hard-wired in a region of brain responsible for compulsive behavior and addiction, leaving an enduring mark that pushes us to succumb to our cravings. The greater the change in the brain circuitry, the more difficult it is to kick a habit.
For their study, published today in the journal Neuron, the Duke scientists analyzed the brains of mice who developed a sugar dependency and compared those with otherwise healthy mice. The rodents developed the habit by pressing a small lever to receive a sugary treat. After the sweets were taken away, the sugar-addicted mice continued pressing the lever even without the reward.
Within the brain is an area known as the basal ganglia, which is responsible for motor action and compulsive behaviors. Two pathways in the basal ganglia carry separate, opposing messages, “stop” and “go.”
For the mice who formed a sugar dependency, the researchers were surprised to find both the “stop” and “go” signals ramped up in the brain compared with ordinary mice.
The timing of the activation of these pathways differed in the two groups as well. For the mice that formed the habit, the go pathway lit up before stop. The opposite pattern emerged in the other test group. The head start given to the go pathway could explain difficulties in self control for those working to correct compulsive behaviors.
Encouraged by the researchers, some mice were able to break the habit when the scientists rewarded only the rodents who stopped pressing the lever, though the mice most able to do this were the ones with the weaker go pathways.
Knowing the influence of addictive, self-destructive behaviors on brain circuitry could lead to treatments to break them, such as transcranial magnetic stimulation, or using harmless magnetic pulses to stimulate the brain, an avenue some researchers have already begun exploring.
Read more at Discovery News
According to new research by Duke University researchers, our vices are hard-wired in a region of brain responsible for compulsive behavior and addiction, leaving an enduring mark that pushes us to succumb to our cravings. The greater the change in the brain circuitry, the more difficult it is to kick a habit.
For their study, published today in the journal Neuron, the Duke scientists analyzed the brains of mice who developed a sugar dependency and compared those with otherwise healthy mice. The rodents developed the habit by pressing a small lever to receive a sugary treat. After the sweets were taken away, the sugar-addicted mice continued pressing the lever even without the reward.
Within the brain is an area known as the basal ganglia, which is responsible for motor action and compulsive behaviors. Two pathways in the basal ganglia carry separate, opposing messages, “stop” and “go.”
For the mice who formed a sugar dependency, the researchers were surprised to find both the “stop” and “go” signals ramped up in the brain compared with ordinary mice.
The timing of the activation of these pathways differed in the two groups as well. For the mice that formed the habit, the go pathway lit up before stop. The opposite pattern emerged in the other test group. The head start given to the go pathway could explain difficulties in self control for those working to correct compulsive behaviors.
Encouraged by the researchers, some mice were able to break the habit when the scientists rewarded only the rodents who stopped pressing the lever, though the mice most able to do this were the ones with the weaker go pathways.
Knowing the influence of addictive, self-destructive behaviors on brain circuitry could lead to treatments to break them, such as transcranial magnetic stimulation, or using harmless magnetic pulses to stimulate the brain, an avenue some researchers have already begun exploring.
Read more at Discovery News
Jan 20, 2016
New Carnivorous Dinosaur 'Draco' Found
A very early carnivorous dinosaur has just been found within rocks of a cliff in the south of Wales.
The dinosaur, named Dracoraptor hanigani or Draco for short, represents the first dinosaur from the Jurassic of Wales, according to a study, published in the journal PLOS ONE. The over 200-million-year-old dino is believed to be the earliest known Jurassic dinosaur from the U.K.
Lead author David Martill of the University of Portsmouth and his team wrote that "the remains of dinosaurs in Wales are exceedingly rare." This makes the discovery all the more important.
Wales might have once been a hotbed of dino activity, however, as the researchers suspect that "lack of preservation" is the primary reason why Jurassic dinosaurs have not been found there before.
Dracoraptor means "dragon robber." A dragon is the national symbol of Wales, so the dino's name reflects local pride over the new find.
Based on the dinosaur's fossils and the location of its remains — a site called Lavernock Point — the researchers believe Draco was an agile hunter that lived along a shoreline. South Wales during the early Jurassic was a coastal region like it is now, but the climate during the dinosaur's lifetime would have been much warmer.
Draco was just over two feet tall and about 6.5 feet wide, which is small for a meat-eating dinosaur. Martill and his colleagues therefore think the individual might have died as a juvenile. Further evidence is that its bones were not yet fully formed or fused.
Even at this young age Draco sported a distinctive long tail, which the researchers think helped with balance.
Read more at Discovery News
The dinosaur, named Dracoraptor hanigani or Draco for short, represents the first dinosaur from the Jurassic of Wales, according to a study, published in the journal PLOS ONE. The over 200-million-year-old dino is believed to be the earliest known Jurassic dinosaur from the U.K.
Lead author David Martill of the University of Portsmouth and his team wrote that "the remains of dinosaurs in Wales are exceedingly rare." This makes the discovery all the more important.
Wales might have once been a hotbed of dino activity, however, as the researchers suspect that "lack of preservation" is the primary reason why Jurassic dinosaurs have not been found there before.
Dracoraptor means "dragon robber." A dragon is the national symbol of Wales, so the dino's name reflects local pride over the new find.
Based on the dinosaur's fossils and the location of its remains — a site called Lavernock Point — the researchers believe Draco was an agile hunter that lived along a shoreline. South Wales during the early Jurassic was a coastal region like it is now, but the climate during the dinosaur's lifetime would have been much warmer.
Draco was just over two feet tall and about 6.5 feet wide, which is small for a meat-eating dinosaur. Martill and his colleagues therefore think the individual might have died as a juvenile. Further evidence is that its bones were not yet fully formed or fused.
Even at this young age Draco sported a distinctive long tail, which the researchers think helped with balance.
Read more at Discovery News
Extinct Crustacean Dollocaris Was All Eyes
A tiny but scary-looking marine critter that died out with the dinosaurs, caught prey with the aid of two monstrous eyes — each a quarter of its body length, scientists said Tuesday.
The giant peepers were composed of 18,000 lenses each — a record only ever surpassed by modern-day dragonflies, a team wrote in the science journal Nature Communications.
The sophisticated organs belonged to Dollocaris ingens, an extinct arthropod which lived about 160 million years ago, during the Jurassic geological period better known for the rise and fall of the dinosaurs.
An arthropod is an animal with an exoskeleton and segmented body — including groups like today’s insects, spiders and crustaceans.
D. ingens, a swimmer, would have had a crab-like shell, with three pairs of clawed, segmented legs with which to catch tiny shrimps, and eight pairs of stubby swimming appendages.
It would have been about five to 20 centimetres (two to eight inches) long, and each eye about a quarter of that.
For the study, experts used special microscopes and scans to examine fossilised D. ingens eyes dug up in southeast France.
It is extremely rare to find well-preserved samples of internal eye structure.
The first compound eyes, made up of many individual units like those of ants, are thought to have appeared in the Cambrian period some 500 million years ago — revolutionising animal development, according to study co-author Jean Vannier from France’s University of Lyon.
“To see and be seen changed everything — with eyes you could become a more effective hunter, while prey became more easily detectable,” he explained.
“All this led to a new dynamic — for some to better protect themselves, for others to become better at detection, and new evolutionary pressures.”
Their examinations confirmed that C. ingens was a “visual hunter,” said Vannier.
Read more at Discovery News
The giant peepers were composed of 18,000 lenses each — a record only ever surpassed by modern-day dragonflies, a team wrote in the science journal Nature Communications.
The sophisticated organs belonged to Dollocaris ingens, an extinct arthropod which lived about 160 million years ago, during the Jurassic geological period better known for the rise and fall of the dinosaurs.
An arthropod is an animal with an exoskeleton and segmented body — including groups like today’s insects, spiders and crustaceans.
D. ingens, a swimmer, would have had a crab-like shell, with three pairs of clawed, segmented legs with which to catch tiny shrimps, and eight pairs of stubby swimming appendages.
It would have been about five to 20 centimetres (two to eight inches) long, and each eye about a quarter of that.
For the study, experts used special microscopes and scans to examine fossilised D. ingens eyes dug up in southeast France.
It is extremely rare to find well-preserved samples of internal eye structure.
The first compound eyes, made up of many individual units like those of ants, are thought to have appeared in the Cambrian period some 500 million years ago — revolutionising animal development, according to study co-author Jean Vannier from France’s University of Lyon.
“To see and be seen changed everything — with eyes you could become a more effective hunter, while prey became more easily detectable,” he explained.
“All this led to a new dynamic — for some to better protect themselves, for others to become better at detection, and new evolutionary pressures.”
Their examinations confirmed that C. ingens was a “visual hunter,” said Vannier.
Read more at Discovery News
Fairy Tales Predate Bible and Greek Myths
Many well known fairy tales predate the existence of modern European languages and major world religions, finds new research.
The findings, published in the journal Royal Society Open Science, open up the possibility that popular folktales influenced writings in Greek and Roman mythology, the Bible and other religious works. They also negate the claims of some scholars who have held that most traditional fairy tales originated much more recently.
"Versions of 'Beauty and the Beast,' 'Rumplestiltskin' and 'Jack and the Beanstalk' have probably been around since before the existence of many modern European languages, like English, German, Russian and French, and would have originally been told in a now extinct ancestral language from which those tongues evolved," co-author Jamshid Tehrani of Durham University told Discovery News.
Tehrani added, “It is difficult to put precise dates on such things, but we're looking in the region of 4–6,000 years old.”
Tehrani and co-author Sara Graça da Silva of the New University of Lisbon investigated whether 275 Indo-European fairy tales were more likely to be shared by closely related populations than more distantly related ones. They tested whether the sharing of the tales could be predicted by how close populations were geographically, or by how related their languages are.
The process enabled the researchers to separate the effects of tales traveling between neighboring groups (such as through trade or migrations) from tales that had been inherited from common ancestral groups. This narrowed the number of tales down to 76 whose distributions could be primarily explained by common heritage.
The researchers next mapped the 76 tales on a "family tree" of Indo-European languages to see how far the stories could be traced back, using the same techniques that biologists utilize to reconstruct the evolution of genetically inherited traits.
One of the oldest tales of the bunch was determined to be "The Smith and the Devil," in which a blacksmith sells his soul to a devil/evil spirit in return for the power to weld any materials together. The blacksmith then uses that power to attach the devil to a stool or tree, and only releases the devil on the condition that he may keep his soul.
"We trace this tale back to the Bronze Age ancestors of the Indo-European language family," Tehrani said.
The age of the tale and its subject help to resolve a long-standing issue among historians. Previously it was thought that Indo-European languages originated prior to metallurgy, but the researchers now think that is highly unlikely.
"Potentially we could use the information preserved in folktales to extrapolate other features of ancestral societies, such as their religious beliefs, moral ideas, gender norms and more," Tehrani said.
Graça da Silva added that many of the early folk tales included animals in the stories. She described an influential one, called "The Grateful Animals," whose plot concerns a group of grateful animals that helps a hero after he rescues them. Usually the animals assist the hero in winning the affections of a princess.
Many of the tales in Grimms’ collection were actually told by women and were often shared by word of mouth. So it's not surprising that themes such as marriage, childbirth, sex and children abound. Later, however, some of these stories underwent various adaptations as they were collected (very often by men), "becoming manuals of proper behavior and a reflection of cultural and social expectations," Graça da Silva said. "Bad girls are usually portrayed as ugly and greedy, for example."
Jack Zipes, a professor emeritus from the University of Minnesota, is a renowned expert on the origin and evolution of fairytales.
He told Discovery News, "Tehrani and Graça da Silva have clearly and scientifically demonstrated that the origins of folk and fairy tales can indeed be traced back to ancient societies by using phylogenetic methods. Their work can serve as the ground work for studies that investigate why certain tale types originated, how they were disseminated and spread throughout the world, and why we keep telling the same tales though different modalities in the present."
Read more at Discovery News
The findings, published in the journal Royal Society Open Science, open up the possibility that popular folktales influenced writings in Greek and Roman mythology, the Bible and other religious works. They also negate the claims of some scholars who have held that most traditional fairy tales originated much more recently.
"Versions of 'Beauty and the Beast,' 'Rumplestiltskin' and 'Jack and the Beanstalk' have probably been around since before the existence of many modern European languages, like English, German, Russian and French, and would have originally been told in a now extinct ancestral language from which those tongues evolved," co-author Jamshid Tehrani of Durham University told Discovery News.
Tehrani added, “It is difficult to put precise dates on such things, but we're looking in the region of 4–6,000 years old.”
Tehrani and co-author Sara Graça da Silva of the New University of Lisbon investigated whether 275 Indo-European fairy tales were more likely to be shared by closely related populations than more distantly related ones. They tested whether the sharing of the tales could be predicted by how close populations were geographically, or by how related their languages are.
The process enabled the researchers to separate the effects of tales traveling between neighboring groups (such as through trade or migrations) from tales that had been inherited from common ancestral groups. This narrowed the number of tales down to 76 whose distributions could be primarily explained by common heritage.
The researchers next mapped the 76 tales on a "family tree" of Indo-European languages to see how far the stories could be traced back, using the same techniques that biologists utilize to reconstruct the evolution of genetically inherited traits.
One of the oldest tales of the bunch was determined to be "The Smith and the Devil," in which a blacksmith sells his soul to a devil/evil spirit in return for the power to weld any materials together. The blacksmith then uses that power to attach the devil to a stool or tree, and only releases the devil on the condition that he may keep his soul.
"We trace this tale back to the Bronze Age ancestors of the Indo-European language family," Tehrani said.
The age of the tale and its subject help to resolve a long-standing issue among historians. Previously it was thought that Indo-European languages originated prior to metallurgy, but the researchers now think that is highly unlikely.
"Potentially we could use the information preserved in folktales to extrapolate other features of ancestral societies, such as their religious beliefs, moral ideas, gender norms and more," Tehrani said.
Graça da Silva added that many of the early folk tales included animals in the stories. She described an influential one, called "The Grateful Animals," whose plot concerns a group of grateful animals that helps a hero after he rescues them. Usually the animals assist the hero in winning the affections of a princess.
Many of the tales in Grimms’ collection were actually told by women and were often shared by word of mouth. So it's not surprising that themes such as marriage, childbirth, sex and children abound. Later, however, some of these stories underwent various adaptations as they were collected (very often by men), "becoming manuals of proper behavior and a reflection of cultural and social expectations," Graça da Silva said. "Bad girls are usually portrayed as ugly and greedy, for example."
Jack Zipes, a professor emeritus from the University of Minnesota, is a renowned expert on the origin and evolution of fairytales.
He told Discovery News, "Tehrani and Graça da Silva have clearly and scientifically demonstrated that the origins of folk and fairy tales can indeed be traced back to ancient societies by using phylogenetic methods. Their work can serve as the ground work for studies that investigate why certain tale types originated, how they were disseminated and spread throughout the world, and why we keep telling the same tales though different modalities in the present."
Read more at Discovery News
Earth's 2015 Temperatures Warmest on Record
Earth’s surface temperatures in 2015 were the warmest since modern-day record keeping began in 1880, two U.S. government agencies reported Wednesday.
Even without naturally occurring warming trends, such as El Nino, 2015 would have been hotter than 2014, also a record-setter, NASA and the National Oceanic and Atmospheric Administration told reporters during a conference call.
Most of the heating is due to the combined effects of deforestation with the burning of fossil fuels, leaving more heat-trapping carbon dioxide and other greenhouse gases in the atmosphere, said Gavin Schmidt, head of NASA’s Goddard Institute for Space Studies in New York.
“Even without El Nino, this would have been the warmest year on record,” Schmidt said.
El Nino, a tropical Pacific Ocean warming system that kicked in during the last three months of 2015 and remains strong, portends an even warmer 2016.
“If you’re going to be betting, you’d bet that it’s going to be warmer than 2015,” said Thomas Karl, director of NOAA's National Centers for Environmental Information in Asheville, North Carolina.
The independent studies by NASA and NOAA align with previously announced research by British and Japanese scientists, all showing Earth heating up to record levels in 2015.
"Clearly, the 2015 data continues the pattern we've seen over the last four to five decades," Karl said.
The warmer temperatures may impact the frequency, intensity and locations of extreme weather events, such as flooding and hurricanes. Global warming also is tied to Arctic ice melt and rising seas.
"This trend will continue ... because the factors that are causing this long-term trend are continuing to accelerate," Schmidt said.
Read more at Discovery News
Even without naturally occurring warming trends, such as El Nino, 2015 would have been hotter than 2014, also a record-setter, NASA and the National Oceanic and Atmospheric Administration told reporters during a conference call.
Most of the heating is due to the combined effects of deforestation with the burning of fossil fuels, leaving more heat-trapping carbon dioxide and other greenhouse gases in the atmosphere, said Gavin Schmidt, head of NASA’s Goddard Institute for Space Studies in New York.
“Even without El Nino, this would have been the warmest year on record,” Schmidt said.
El Nino, a tropical Pacific Ocean warming system that kicked in during the last three months of 2015 and remains strong, portends an even warmer 2016.
“If you’re going to be betting, you’d bet that it’s going to be warmer than 2015,” said Thomas Karl, director of NOAA's National Centers for Environmental Information in Asheville, North Carolina.
The independent studies by NASA and NOAA align with previously announced research by British and Japanese scientists, all showing Earth heating up to record levels in 2015.
"Clearly, the 2015 data continues the pattern we've seen over the last four to five decades," Karl said.
The warmer temperatures may impact the frequency, intensity and locations of extreme weather events, such as flooding and hurricanes. Global warming also is tied to Arctic ice melt and rising seas.
"This trend will continue ... because the factors that are causing this long-term trend are continuing to accelerate," Schmidt said.
Read more at Discovery News
9th Planet May Lurk in the Outer Solar System
The astronomer who helped kick Pluto out of the planet club believes a much larger body may be lurking in the outskirts of the solar system.
If it exists, the solar system’s ninth planet is estimated to be a gas world about 10 times bigger than Earth, California Institute of Technology (Caltech) astronomer Mike Brown wrote in this week’s Astronomical Journal.
Brown and colleague Konstantin Batygin, also at Caltech, used mathematical models and computer simulations to deduce the planet’s existence, but they also have some observational evidence to support their claim. Several small icy bodies in the Kuiper Belt region beyond Neptune have quirks in their orbits that may be explained by the gravitational influence of a larger, more distant planetary cousin.
Scientists then realized that six of those bodies follow elliptical paths pointing toward the same direction in space.
“It’s almost like having six hands on a clock all moving at different rates, and when you happen to look up, they’re all in exactly the same place,” Brown said in a press release, adding that the odds of that happening are about one-in-100.
The orbits also are tilted in the same direction, roughly 30 degrees downward relative to the orbital plane of the solar system’s other eight planets.
“We thought something else must be shaping these orbits,” Brown said.
After checking if a batch of other Kuiper Belt objects might be responsible, the scientists started doing computer simulations that included a distant outer planet in various orbits.
They found an unusual match: a massive planet in an anti-aligned orbit, which is an orbit in which the planet’s closest approach to the sun is 180 degrees across from the closest approach of the objects and known planets in the solar system.
“I was very skeptical,” Batygin said in the release. “I had never seen anything like this in celestial mechanics.”
Besides accounting for peculiarities in some Kuiper Belt objects’ orbits, the predicted rogue planet, located about 20 times farther away from the sun than Earth, also would pin other Kuiper Belt bodies into orbits perpendicular to the plane of the rest of the planets.
Read more at Discovery News
If it exists, the solar system’s ninth planet is estimated to be a gas world about 10 times bigger than Earth, California Institute of Technology (Caltech) astronomer Mike Brown wrote in this week’s Astronomical Journal.
Brown and colleague Konstantin Batygin, also at Caltech, used mathematical models and computer simulations to deduce the planet’s existence, but they also have some observational evidence to support their claim. Several small icy bodies in the Kuiper Belt region beyond Neptune have quirks in their orbits that may be explained by the gravitational influence of a larger, more distant planetary cousin.
Scientists then realized that six of those bodies follow elliptical paths pointing toward the same direction in space.
“It’s almost like having six hands on a clock all moving at different rates, and when you happen to look up, they’re all in exactly the same place,” Brown said in a press release, adding that the odds of that happening are about one-in-100.
The orbits also are tilted in the same direction, roughly 30 degrees downward relative to the orbital plane of the solar system’s other eight planets.
“We thought something else must be shaping these orbits,” Brown said.
After checking if a batch of other Kuiper Belt objects might be responsible, the scientists started doing computer simulations that included a distant outer planet in various orbits.
They found an unusual match: a massive planet in an anti-aligned orbit, which is an orbit in which the planet’s closest approach to the sun is 180 degrees across from the closest approach of the objects and known planets in the solar system.
“I was very skeptical,” Batygin said in the release. “I had never seen anything like this in celestial mechanics.”
Besides accounting for peculiarities in some Kuiper Belt objects’ orbits, the predicted rogue planet, located about 20 times farther away from the sun than Earth, also would pin other Kuiper Belt bodies into orbits perpendicular to the plane of the rest of the planets.
Read more at Discovery News
Jan 17, 2016
Extreme turbulence roiling 'most luminous galaxy' in the universe
The most luminous galaxy in the Universe -- a so-called obscured quasar 12.4 billion light-years away -- is so violently turbulent that it may eventually jettison its entire supply of star-forming gas, according to new observations with the Atacama Large Millimeter/submillimeter Array (ALMA).
A team of researchers used ALMA to trace, for the first time, the actual motion of the galaxy's interstellar medium -- the gas and dust between the stars. What they found, according to Tanio Díaz-Santos of the Universidad Diego Portales in Santiago, Chile, is a galaxy "so chaotic that it is ripping itself apart."
Previous studies with NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft revealed that the galaxy, dubbed W2246-0526, is glowing in infrared light as intensely as approximately 350 trillion suns.
Evidence strongly suggests that this galaxy is an obscured quasar, a very distant galaxy with a voraciously feeding supermassive black hole at its center that is completely obscured behind a thick blanket of dust.
This galaxy's startling brightness is powered by a tiny, yet incredibly energetic disk of gas that is being superheated as it spirals in on the supermassive black hole. The light from this blazingly bright accretion disk is then absorbed by the surrounding dust, which re-emits the energy as infrared light.
"These properties make this object a beast in the infrared," said Roberto Assef, an astronomer with the Universidad Diego Portales and leader of the ALMA observing team. "The powerful infrared energy emitted by the dust then has a direct and violent impact on the entire galaxy, producing extreme turbulence throughout the interstellar medium."
The astronomers compare this turbulent action to a pot of boiling water. If these conditions continue, they say, the galaxy's intense infrared radiation will boil away all of its interstellar gas.
This galaxy belongs to a very unusual type of quasar known as Hot, Dust-Obscured Galaxies or Hot DOGs. These objects are very rare; only 1 out of every 3,000 quasars observed by WISE belongs to this class.
The astronomers used ALMA to precisely map the motion of ionized carbon atoms throughout the entire galaxy. These atoms, which are tracers for interstellar gas, naturally emit infrared light, which becomes shifted to millimeter wavelengths as it travels the vast cosmic distances to Earth due to the expansion of the Universe.
"Large amounts of ionized carbon were found in an extremely turbulent dynamic state throughout the galaxy," Díaz-Santos describes. The data reveal that this interstellar material is careening anywhere from 500 to 600 kilometers per second throughout the entire galaxy.
The astronomers believe that this turbulence is primarily due to the fact that the region around the black hole is at least 100 times more luminous than the rest of the galaxy combined; in other quasars, the proportion is much more modest. This intense yet localized radiation exerts tremendous pressure on the entire galaxy, to potentially devastating effect.
"We suspected that this galaxy was in a transformative stage of its life because of the enormous amount of infrared energy discovered with WISE," said Peter Eisenhardt with NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Now ALMA has shown us that the raging furnace in this galaxy is making the pot boil over."
Current models of galactic dynamics combined with the ALMA data indicate that this galaxy is unstable and its interstellar gas is being blown away in all directions. This suggests that the galaxy's Hot DOG days are numbered as it matures into a more traditional unobscured quasar.
"If this pattern continues, it is possible that in the future W2246 ends up shedding a large part of the gas and dust it contains," concludes Manuel Aravena also from the Universidad Diego Portales. "Only ALMA, with its unparalleled resolution, can allow us to see this object in high definition and fathom such an important episode in the life of this galaxy."
Notes:
"The Strikingly Uniform, Highly Turbulent Interstellar Medium of The Most Luminous Galaxy in the Universe," by T. Díaz-Santos et al., and will be published in the Astrophysical Journal Letters.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
The team is composed of T. Díaz-Santos (Universidad Diego Portales, Santiago, Chile), R. J. Assef (Universidad Diego Portales, Santiago, Chile), A. W. Blain (University of Leicester, UK) , C.-W. Tsai (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA) , M. Aravena (Universidad Diego Portales, Santiago, Chile), P. Eisenhardt (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), J. Wu (University of California Los Angeles, California, USA), D. Stern (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA) and C. Bridge (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA).
Read more at Science Daily
A team of researchers used ALMA to trace, for the first time, the actual motion of the galaxy's interstellar medium -- the gas and dust between the stars. What they found, according to Tanio Díaz-Santos of the Universidad Diego Portales in Santiago, Chile, is a galaxy "so chaotic that it is ripping itself apart."
Previous studies with NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft revealed that the galaxy, dubbed W2246-0526, is glowing in infrared light as intensely as approximately 350 trillion suns.
Evidence strongly suggests that this galaxy is an obscured quasar, a very distant galaxy with a voraciously feeding supermassive black hole at its center that is completely obscured behind a thick blanket of dust.
This galaxy's startling brightness is powered by a tiny, yet incredibly energetic disk of gas that is being superheated as it spirals in on the supermassive black hole. The light from this blazingly bright accretion disk is then absorbed by the surrounding dust, which re-emits the energy as infrared light.
"These properties make this object a beast in the infrared," said Roberto Assef, an astronomer with the Universidad Diego Portales and leader of the ALMA observing team. "The powerful infrared energy emitted by the dust then has a direct and violent impact on the entire galaxy, producing extreme turbulence throughout the interstellar medium."
The astronomers compare this turbulent action to a pot of boiling water. If these conditions continue, they say, the galaxy's intense infrared radiation will boil away all of its interstellar gas.
This galaxy belongs to a very unusual type of quasar known as Hot, Dust-Obscured Galaxies or Hot DOGs. These objects are very rare; only 1 out of every 3,000 quasars observed by WISE belongs to this class.
The astronomers used ALMA to precisely map the motion of ionized carbon atoms throughout the entire galaxy. These atoms, which are tracers for interstellar gas, naturally emit infrared light, which becomes shifted to millimeter wavelengths as it travels the vast cosmic distances to Earth due to the expansion of the Universe.
"Large amounts of ionized carbon were found in an extremely turbulent dynamic state throughout the galaxy," Díaz-Santos describes. The data reveal that this interstellar material is careening anywhere from 500 to 600 kilometers per second throughout the entire galaxy.
The astronomers believe that this turbulence is primarily due to the fact that the region around the black hole is at least 100 times more luminous than the rest of the galaxy combined; in other quasars, the proportion is much more modest. This intense yet localized radiation exerts tremendous pressure on the entire galaxy, to potentially devastating effect.
"We suspected that this galaxy was in a transformative stage of its life because of the enormous amount of infrared energy discovered with WISE," said Peter Eisenhardt with NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Now ALMA has shown us that the raging furnace in this galaxy is making the pot boil over."
Current models of galactic dynamics combined with the ALMA data indicate that this galaxy is unstable and its interstellar gas is being blown away in all directions. This suggests that the galaxy's Hot DOG days are numbered as it matures into a more traditional unobscured quasar.
"If this pattern continues, it is possible that in the future W2246 ends up shedding a large part of the gas and dust it contains," concludes Manuel Aravena also from the Universidad Diego Portales. "Only ALMA, with its unparalleled resolution, can allow us to see this object in high definition and fathom such an important episode in the life of this galaxy."
Notes:
"The Strikingly Uniform, Highly Turbulent Interstellar Medium of The Most Luminous Galaxy in the Universe," by T. Díaz-Santos et al., and will be published in the Astrophysical Journal Letters.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
The team is composed of T. Díaz-Santos (Universidad Diego Portales, Santiago, Chile), R. J. Assef (Universidad Diego Portales, Santiago, Chile), A. W. Blain (University of Leicester, UK) , C.-W. Tsai (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA) , M. Aravena (Universidad Diego Portales, Santiago, Chile), P. Eisenhardt (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), J. Wu (University of California Los Angeles, California, USA), D. Stern (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA) and C. Bridge (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA).
Read more at Science Daily
'Green pea' galaxy provides insights to early universe evolution
Newly formed dwarf galaxies were likely the reason that the universe heated up about 13 billion years ago, according to new work by an international team of scientists that included a University of Virginia researcher. The finding opens an avenue for better understanding the early period of the universe's 14 billion year history.
In the period of several hundred thousand years after the Big Bang, the universe was so hot and dense that matter was ionized instead of being in a neutral form. But 380,000 years later, the expansion of the universe had cooled it enough for matter to become neutral and for the first structures of the universe to form -- gas clouds of hydrogen and helium. Gravity then made these gas clouds grow in mass and collapse to form the first stars and galaxies. Then, about one billion years after the Big Bang, another important transformation occurred: the universe reheated, and hydrogen -- the most abundant element -- became ionized for a second time, as it had shortly after the Big Bang, an event which astronomers call "cosmic re-ionization." How this happened is still debated.
Astronomers have long thought that galaxies were responsible for this transformation.
An international team of scientists, organized by University of Virginia astronomer Trinh Thuan in the United States, has largely validated that hypothesis in a paper published Thursday in the journal Nature. Trinh's research colleagues on the paper are at institutions in Ukraine, the Czech Republic, Switzerland, France and Germany.
Using data from an ultraviolet spectrometer aboard the Hubble Space Telescope, the team discovered a nearby compact dwarf galaxy emitting a large number of ionizing photons into the intergalactic medium, or the space between galaxies. Scientists believe those photons are responsible for the universe's re-ionization.
"This galaxy appears to be an excellent local analog of the numerous dwarf galaxies thought to be responsible for the reionization of the early universe," Trinh said. "The finding is significant because it gives us a good place to look for probing the reionization phenomenon, which took place early in the formation of the universe that became the universe we have today."
Normal matter in the early universe consisted mostly of gas. Stars and star clusters are born from clouds of gas, forming the first galaxies. Ultraviolet radiation emitted by these stars contains numerous ionizing photons. For this reason, scientists have long suspected that galaxies were responsible for cosmic reionization. However, for reionization to occur, galaxies must eject these photons into the intergalactic medium; otherwise, they are easily absorbed by the gas and dust before they can escape. Despite 20 years of intensive searching, no galaxy emitting sufficient ionizing radiation had been found, and the mechanism by which the universe became re-ionized remained a mystery.
To solve this problem, the international research team proposed to observe "green pea" galaxies. Discovered in 2007, these galaxies represent a special and rare class in the nearby universe. They appear green to light sensors and are round and compact, like a pea. They are believed to host stellar explosions or winds strong enough to eject ionizing photons.
The team examined data from the Sloan Digital Sky Survey -- a database of more than a million galaxies. From this survey, they identified approximately 5,000 galaxies that match their criteria: very compact galaxies emitting very intense UV radiation. Researchers selected five galaxies for observation with the Hubble Space Telescope.
Read more at Science Daily
In the period of several hundred thousand years after the Big Bang, the universe was so hot and dense that matter was ionized instead of being in a neutral form. But 380,000 years later, the expansion of the universe had cooled it enough for matter to become neutral and for the first structures of the universe to form -- gas clouds of hydrogen and helium. Gravity then made these gas clouds grow in mass and collapse to form the first stars and galaxies. Then, about one billion years after the Big Bang, another important transformation occurred: the universe reheated, and hydrogen -- the most abundant element -- became ionized for a second time, as it had shortly after the Big Bang, an event which astronomers call "cosmic re-ionization." How this happened is still debated.
Astronomers have long thought that galaxies were responsible for this transformation.
An international team of scientists, organized by University of Virginia astronomer Trinh Thuan in the United States, has largely validated that hypothesis in a paper published Thursday in the journal Nature. Trinh's research colleagues on the paper are at institutions in Ukraine, the Czech Republic, Switzerland, France and Germany.
Using data from an ultraviolet spectrometer aboard the Hubble Space Telescope, the team discovered a nearby compact dwarf galaxy emitting a large number of ionizing photons into the intergalactic medium, or the space between galaxies. Scientists believe those photons are responsible for the universe's re-ionization.
"This galaxy appears to be an excellent local analog of the numerous dwarf galaxies thought to be responsible for the reionization of the early universe," Trinh said. "The finding is significant because it gives us a good place to look for probing the reionization phenomenon, which took place early in the formation of the universe that became the universe we have today."
Normal matter in the early universe consisted mostly of gas. Stars and star clusters are born from clouds of gas, forming the first galaxies. Ultraviolet radiation emitted by these stars contains numerous ionizing photons. For this reason, scientists have long suspected that galaxies were responsible for cosmic reionization. However, for reionization to occur, galaxies must eject these photons into the intergalactic medium; otherwise, they are easily absorbed by the gas and dust before they can escape. Despite 20 years of intensive searching, no galaxy emitting sufficient ionizing radiation had been found, and the mechanism by which the universe became re-ionized remained a mystery.
To solve this problem, the international research team proposed to observe "green pea" galaxies. Discovered in 2007, these galaxies represent a special and rare class in the nearby universe. They appear green to light sensors and are round and compact, like a pea. They are believed to host stellar explosions or winds strong enough to eject ionizing photons.
The team examined data from the Sloan Digital Sky Survey -- a database of more than a million galaxies. From this survey, they identified approximately 5,000 galaxies that match their criteria: very compact galaxies emitting very intense UV radiation. Researchers selected five galaxies for observation with the Hubble Space Telescope.
Read more at Science Daily
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