'Death stars' in Orion blast planets before they even form

The Orion Nebula is home to hundreds of young stars and even younger protostars known as proplyds. Many of these nascent systems will go on to develop planets, while others will have their planet-forming dust and gas blasted away by the fierce ultraviolet radiation emitted by massive O-type stars that lurk nearby.

A team of astronomers from Canada and the United States has used the Atacama Large Millimeter/submillimeter Array (ALMA) to study the often deadly relationship between highly luminous O-type stars and nearby protostars in the Orion Nebula. Their data reveal that protostars within 0.1 light-years (about 600 billion miles) of an O-type star are doomed to have their cocoons of dust and gas stripped away in just a few millions years, much faster than planets are able to form.

"O-type stars, which are really monsters compared to our Sun, emit tremendous amounts of ultraviolet radiation and this can play havoc during the development of young planetary systems," remarked Rita Mann, an astronomer with the National Research Council of Canada in Victoria, and lead author on a paper in the Astrophysical Journal. "Using ALMA, we looked at dozens of embryonic stars with planet-forming potential and, for the first time, found clear indications where protoplanetary disks simply vanished under the intense glow of a neighboring massive star."

Many, if not all, Sun-like stars are born in crowded stellar nurseries similar to the Orion Nebula. Over the course of just a few million years, grains of dust and reservoirs of gas combine into larger, denser bodies. Left relatively undisturbed, these systems will eventually evolve into fully fledged star systems, with planets -- large and small -- and ultimately drift away to become part of the galactic stellar population.

Astronomers believe that massive yet short-lived stars in and around large interstellar clouds are essential for this ongoing process of star formation. At the end of their lives, massive stars explode as supernovas, seeding the surrounding area with dust and heavy elements that will get taken up in the next generation of stars. These explosions also provide the kick necessary to initiate a new round of star and planet formation. But while they still shine bright, these larger stars can be downright deadly to planets if an embryonic solar systems strays too close.

"Massive stars are hot and hundreds of times more luminous than our Sun," said James Di Francesco, also with the National Research Council of Canada. "Their energetic photons can quickly deplete a nearby protoplanetary disk by heating up its gas, breaking it up, and sweeping it away."

Earlier observations with the Hubble Space Telescope revealed striking images of proplyds in Orion. Many had taken on tear-drop shapes, with their dust and gas trailing away from a nearby massive star. These optical images, however, couldn't reveal anything about the amount of dust that was present or how the dust and gas concentrations changed in relation to massive stars.

The new ALMA observations detected these and other never-before-imaged proplyds, essentially doubling the number of protoplanetary disks discovered in that region. ALMA also could see past their surface appearance, peering deep inside to actually measure how much mass was in the proplyds.

Combining these studies with previous observations from the Submillimeter Array (SMA) in Hawai'i, the researchers found that any protostar within the extreme-UV envelope of a massive star would have much of its disk of material destroyed in very short order. Proplyds in these close-in regions retained only a fraction (one half or less) of the mass necessary to create one Jupiter-size planet. Beyond the 0.1 light-year radius, in the far-UV dominated region, the researchers observed a wide range of disk masses containing anywhere for one to 80 times the mass of Jupiter. This is similar to the amount of dust found in low-mass star forming regions.

Read more at Science Daily

Chimps Trust Some People More Than Other Chimps

Chimpanzees that have had positive experiences with humans appear to trust people more than they do baboons and unfamiliar chimps, a new study suggests.

The findings, published in the latest Proceedings of the Royal Society B, indicate that chimpanzees can learn to bond and exhibit empathy for members of another species, such that trust develops even at the subconscious level.

As for what chimps think of kind and caring humans, lead author Matthew Campbell told Discovery News, "I have no doubt that we are different in their minds, but an okay kind of different."

Campbell, a researcher at the Yerkes National Primate Research Center, said that an older female chimp named Tai is so pleased to see co-author Frans de Waal, whom she's known for 20 years, that she excitedly pants, bobs her head and stretches out her hand. All of these are behaviors chimps use when greeting each other.

For the study, Campbell and de Waal used contagious yawning to measure "involuntary empathy" among 19 adult chimps at Yerkes that were all raised by other chimps in captivity.

"We think that the mechanism for copying the yawns of others is the same for copying other facial expressions, like happiness, sadness or fear," he explained. "For our purposes, yawning is simply a contagious expression we can easily see and count. Contagious smiles, frowns and fearful expressions may be tiny twitches of muscles that cannot be seen, but yawns can't be missed."

He added, "We catch all of these expressions more the closer we feel to someone, and that's why we think that empathy is involved."

The behavior is further thought to occur at the subconscious level, suggesting that the trust between the individuals happens this deeply as well.

The chimpanzees yawned in sync with humans, as well as trusted family members and chimp friends. They did not exhibit such involuntary empathy for unfamiliar chimpanzees and Gelada baboons, however.

The researchers conclude that their responses were based on life experiences.

"I think that they may have been conditioned to think that humans are generally okay," Campbell explained. "Therefore, meting a new human may be an opportunity for a new positive interaction, since that has been their experience."

Chimpanzees are territorial in the wild and exclude strangers, so unfamiliar chimps could have evoked an innate hostile response. Baboons, on the other hand, are "basically meaningless" to these captive chimps, so the chimps were indifferent to them.

Chimpanzees, therefore, are not completely hard-wired to feel a certain way about any given primate, including humans. They instead show flexibility in forming trusted, empathic connections with different species, including unknown members of that species.

Read more at Discovery News

Elephants Can Tell Gender, Ethnicity in Human Voices

African elephants can differentiate between human languages and move away from those considered a threat, a skill they have honed to survive in the wild, researchers said.

The study suggests elephants, already known to be intelligent creatures, are even more sophisticated than previously believed when it comes to understanding human dangers.

African elephants (Loxodonta africana) are the largest land animals on Earth and are considered a vulnerable species due to habitat loss and illegal hunting for their ivory tusks.

Researchers played recordings of human voices for elephants at Amboseli National Park in Kenya to see how they would respond, according to a report in the Proceedings of the National Academy of Sciences.

Some of the voices were from local Maasai men, a group that herds cattle and sometimes comes into conflict with elephants over access to water and grazing space. Occasionally, elephants are killed in clashes with Maasai men, and vice-versa.

Other recorded voices were from Kamba men, who tend to be farmers or employees of the national park, and who rarely represent a danger to elephants.

Still other voices tested on the elephants included female Maasai speakers and young boys.

All were saying the same phrase: "Look, look over there, a group of elephants is coming."

The recorded voices were played for hundreds of elephants across 47 family groups during daylight hours.

When elephants heard the adult male Maasai voices, they tended to gather together, start investigative smelling with their trunks, and move cautiously away.

But when elephants heard females, boys, or adult male Kamba speakers, they did not show concern.

Discriminating between languages

"The ability to distinguish between Maasai and Kamba men delivering the same phrase in their own language suggests that elephants can discriminate between different languages," said co-author Graeme Shannon, a visiting fellow in psychology at the University of Sussex.

That is not the same as understanding what the words mean, but still shows that elephants can decipher the more sing-songy Maasai language from the Kamba tongue, perhaps based on inflections, use of vowels, and other cues.

"It is very sophisticated what the elephants are doing," said Keith Lindsay, a conservation biologist and member of the scientific advisory committee of the Amboseli Elephant Research Project.

"A lot of animals will take flight at just the general threat posed by people, but a smart animal doesn't do that," he told AFP.

"Their response to hearing Maasai men talking was to be alert, to move away, but not to run away in total fear," added Lindsay, who was not involved in the study.

"It is suggesting that elephants are capable of thinking, (of) recognizing that if Maasai men are talking, they are not likely to be hunting because if they were hunting, they would be quiet."

Wiser with age

Elephant groups with older matriarchs in their midst did best at assessing the threat from different speakers, further bolstering the presumed role of learning in the animals' behavior.

The elephants also did not act the same way as they did when recordings of lions were played, as was shown in a previous study.

In those scenarios, they bunched together so that juveniles -- those most at risk from a lion attack -- were in the center, and moved toward the sounds as if to scare the lion away.

When it comes to recognizing people, elephants may not be alone in this ability. Other research has suggested that wild bottlenose dolphins in Brazil have become so familiar with humans that they engage in cooperative hunting with artisanal fisherman.

Great apes, crows and even prairie dogs have also been shown to differentiate between humans on some level.

Read more at Discovery News

Venus Express Orbiter Basks in Venusian Glory

The European Space Agency’s Venus Express orbiter has spotted a very terrestrial phenomenon in the high-altitude cloud cover of Earth’s hellish ‘sister’ world.

While orbiting Venus, with the sun at its back, Venus Express used its cameras to observe a “glory” — the rainbow-like halo that is usually seen from an aircraft flying over clouds. This is the first time a glory has been observed on another planet.

Glories appear as tight circular rainbow structures surrounding the shadow of an aircraft and are only formed when the cloud consists of tiny water droplets of approximately same size. On Earth, glories are a rare treat as the atmospheric conditions and location of the observer to the sun need to be just right. But if the conditions are met, sunlight can bounce off the water droplets, refracting back to the observer.

Venus, however, doesn’t have temperate, life-giving water droplets in its high-altitude clouds. But in an effort to determine the characteristics of the droplets contained within the Venusian sulfuric acid clouds, mission scientists waited until the sun was directly behind Venus Express and took this shot of the corrosive clouds far below.

On July 24, 2011, the satellite spotted its first extraterrestrial glory in Venus’ cloud tops 70 kilometers (44 miles) above the planet’s surface. According to an ESA news release, the glory was 1,200 kilometers (746 miles) wide as seen from the spacecraft that was orbiting 6,000 kilometers (3,728 miles) above.

From this observation, scientists have been able to determine the dimensions of Venus’ sulfuric acid cloud drops. They found the droplets to measure 1.2 micrometres across — approximately a fiftieth of the width of a human hair. The fact that the glory was 1,200 kilometers wide suggests that all the droplets within that area were around the same size.

But there were some surprises that may help us understand the complex chemistry at play in Venus’s atmosphere.

“The variations of brightness of the rings of the observed glory is different than that expected from clouds of only sulfuric acid mixed with water, suggesting that other chemistry may be at play,” writes ESA.

Read more at Discovery News

Oldest Masks Go on Display

The first known masks are Halloween-like stone portraits of the dead, according to an upcoming exhibition at the Israel Museum in Jerusalem.

The exhibit, called Face to Face: The Oldest Masks in the World, reveals for the first time 12 Neolithic masks featuring wide toothy smiles and large eyes.

According to the curators, who set up the display after 10 years of investigative work, the eerie stone portraits were carved out of limestone some 9,000 years ago by Stone Age people who were among the first to abandon nomadic life.

Analysis into the type of stone revealed the masks came from the Judean Hills and nearby Judean desert in Israel. Although there is no record of their use — they predate writing by 3,500 years — experts believe the artifacts might represent various ancestors of an early Stone Age religion.

“It is important to say that these are not living people, these are spirits,” Debby Hershman, curator of prehistoric cultures at the Israel Museum who organized the exhibit, told the Times of Israel.

The masks were probably used in rites of healing and magic and in ceremonies celebrating the deceased. They weigh about 2 to 4 pounds and likely would have been painted, as the color traces on one of them suggest.

Each of the 12 masks is unique, and shows old and young faces of various size. One even resembles a human skull.

“They are the first glimmerings of existential reflection,” James Snyder, the museum’s director, told the Times of Israel.

Several masks feature a set of holes along the outer edge, as if they were hung or worn.

Read more at Discovery News

Fickle Sun Changed Europe's Climate for 1,000 Years

Variations in the sun’s output may explain some of the natural changes in Europe’s climate during the past 1,000 years, including the deadly cold winters of the 16th and 18th centuries. Earth scientists recently discovered that as solar output dipped so did temperatures in the North Atlantic, which then may have cooled the climate in Europe.

When the sun produces less energy, known as a solar minima, a high pressure system may form in the atmosphere over the North Atlantic, according to the study published in Nature Geoscience. That high-pressure system blocks warm winds flowing from west to east, known as the westerlies, and allows cold northern air to flow over Europe.

“Indeed we propose that this combined ocean-atmospheric response to solar output minima may help explain the notoriously severe winters experienced across Europe between the 16th and 18th centuries, so vividly depicted in many paintings, including those of the famous London Frost Fairs on the River Thames, but also leading to extensive crop failures and famine as corroborated in the record of wheat prices during these periods,” said lead author Paola Moffa-Sanchez of Cardiff University, in a press release.

This analysis of the interplay between sun, sea and climate used a combinations of fossils, sun-spot records and computer simulations. The chemicals held within fossils of marine microorganism provided information about the temperature and salinity of the ocean over the past millennia.

Sun-spot records gave clues to solar activity, since low numbers of spots means low solar output. The data from fossils and sun spots was then input into a computer to create a model of how solar changes influence Europe’s climate.

Read more at Discovery News

Asteroid Strike Drenched World in Acid Rain

Global ocean acidification caused by acid rain occurred just days after a massive asteroid slammed into the Earth 66 million years ago, new research suggests.

The rapid acidification could explain why surface-dwelling organisms such as ammonites and carbon-secreting plankton were wiped out, while some deep ocean dwellers as well as freshwater species such as crocodiles survived one of the largest mass extinction events in history.

Most scientists believe the Cretaceous-Palaeogene mass extinction event, which wiped out 75 per cent of all life on Earth including the non-avian dinosaurs, was triggered by the impact of a 10-kilometre wide asteroid off Mexico's Yucatan Peninsula.

However, questions about why most species were wiped out while some others survived have remained an area of intense debate among scientists.

The impact, which created the 180-kilometre wide Chicxulub crater, covers an area of seabed that contains anhydrite, a sulphur-rich rock.

While it had been hypothesized that acid rain could have caused the extinction patterns, previous work suggested that sulphur dioxide would have stayed in the atmosphere for months — much too long to cause rapid acidification.

But now Japanese researchers led by Sohsuke Ohno of the Chiba Institute in Japan have examined the composition of the vapor cloud generated by the impact.

Their research, published in the journal Nature Geoscience suggests far more sulphur trioxide than sulphur dioxide was released into the atmosphere.

"Our experiments suggest that the Chicxulub impact released a huge quantity of sulphur trioxide into the atmosphere, where it would have rapidly combined with water vapor to form sulphuric acid aerosol particles," the authors write.

Ohno and colleagues used lasers to fire impactors into anhydrite test samples at velocities of 13 to 25 kilometers per second, which are similar to the speeds expected in an asteroid impact.

The resulting vapour cloud was examined using quadrupole mass spectrometer (QMS) analysis, finding impacts resulted in the release of far more sulphur trioxide molecules than sulphur dioxide.

Sulphur trioxide reacts quickly with atmospheric water vapour to form sulphuric acid aerosols.

These aerosols would stick to heavier silicate debris particles ejected high into the atmosphere by the impact, and would have fallen back to the surface within two days, much faster than previously thought.

Eureka moment

Professor Mike Archer of the University of New South Wales says the extremely intense acid rainfall and dramatic acidification of global marine surface waters explains the disappearance of many species during this period including ammonites and carbonate secreting plankton.

"It's solved a number of mysteries that have always bothered me," says Archer, who was not involved in the research.

"Their work shows the asteroid could have done all the damage that we suspected it did."

Archer says the relatively moderate rates of extinction in freshwater species could be due to the acid-neutralizing effects of the mineral larnite.

"So the crocodiles and many of the terrestrial aquatic organisms would have been able to survive because the acid impact wouldn't have been as bad as it was in the ocean," says Archer.

Read more at Discovery News

'Cosmos: A Spacetime Odyssey': A Triumph for Science

When I first heard that Carl Sagan’s classic “Cosmos” television series from 1980 was going to be remade for a modern audience, I was skeptical. How could Neil deGrasse Tyson hope to carry on where Sagan left off? Would an over-reliance on CGI dumb-down the science to such an extent that it would just be a shiny yet soulless reboot? I’ve always been a huge fan of Tyson’s work, but could a Cosmos 2.0 be too much for the famous science communicator to handle?

But all my reservations about the Cosmos reboot, that premiered Sunday on FOX, were completely unfounded. It was a triumph for science and once again proved that Neil deGrasse Tyson is one of the heavyweight science educators of our time. For this brilliant effort, Tyson teamed up with executive producer and “Family Guy” creator Seth MacFarlane, and Ann Druyan, who co-writer of the original “Cosmos” with her late husband, Sagan.

In the one-hour first episode, “Cosmos: A Spacetime Odyssey” takes us on a dizzying journey from the Big Bang to the very edge of our observable Universe; from the tiniest particles to the galactic superclusters. Tyson gives us a history lesson of the genesis of our modern understanding of the Universe, starting with the oppressed 16th-Century astronomer Giordano Bruno who thought beyond the Copernican Principal, describing an “infinite” Universe containing other stars, planets and even life on those other worlds.

Tragically, Bruno ran afoul with the Roman Catholic Church, which imprisoned and killed him. Bruno’s story was told by Tyson through wonderful animated shorts that enhanced his awesome storytelling abilities.

From Bruno’s realization about the true scale of the Universe, the episode spiraled out to the Cosmic Calendar — first popularized by Sagan in the original “Cosmos” — where the entirety of the history of the Universe is mapped onto our 365 day year. If the Big Bang occurred on Jan. 1, the whole of human history occurred in the final few seconds of Dec. 31.

“Feeling a little small?” asks Tyson. That was the crux of this entire episode: the scale of the Universe is unfathomable and our place in it is baffling, but Cosmos is here to help the audience join the dots and hopefully grasp the immensity of the questions science is asking.

Throughout the show we are treated to some of the best CGI television has to offer and for the most part, the computer generated renderings are scientifically sound (give or take a bit of latitude for dramatic license). Personally, I loved the beach scene where Tyson is describing how life from the oceans evolved to venture onto the land — seamlessly a CGI Tiktaalik, one of the first animals to venture out of the oceans, lumbered onto the beach and it took a moment for me to realize it wasn’t real.

But deep within the spacetime fabric of this Cosmos was a beautiful emotion that had most impact.

In the last 5 minutes, Tyson describes his personal relationship with Sagan. At 17, Tyson was invited to visit Sagan at his home in Ithaca, NY — a period of his life that he remembers with great clarity. Sagan’s hospitality and kindness toward him had a strong resonance at the time. Although Tyson knew he wanted to be an astronomer, he added that he also learned from Carl the kind of person he wanted to become.

Read more at Discovery News

Sponges Likely Paved the Way For All Life on Earth

The seemingly lowly sponge, just by its very existence, might have paved the way for the evolution of complex life forms, including our own species, according to a new paper.

Sponges appear to have added oxygen to the deep ocean, creating an environment where more mobile, major oxygen-using animals could have evolved, holds the paper, published in the latest Nature Geoscience.

The research builds on work, presented earlier this year, which found that the most primitive sponges probably could survive in water containing very low levels of oxygen.

“There had been enough oxygen in ocean surface waters for over 1.5 billion years before the first animals evolved, but the dark depths of the ocean remained devoid of oxygen,” lead author Tim Lenton of the University of Exeter was quoted as saying in a press release. “We argue that the evolution of the first animals could have played a key role in the widespread oxygenation of the deep oceans. This in turn may have facilitated the evolution of more complex, mobile animals.”

Several lines of evidence support the theory. DNA analysis finds that the earliest sponges likely first emerged at least 700 million years ago, when the oceans contained little oxygen. Between 700 and 600 million years ago, the oceans gradually became more oxygenated, meaning more enriched with oxygen. Fossils of animals dating to 650 million years ago have been found.

Then there is the way that sponges feed. These multicellular organisms consist of pores and channels that allow nutrient-containing water to circulate through them.

As sponges feed, they filter out tiny particles of organic matter from the water. The particles millions of years ago would have included dead microbial matter, which rots and consumes oxygen as it does so. Sponges therefore helped to clean water of this material. Without all of the rotting going on, the water would have experienced increased oxygen levels, the researchers suggest.

More oxygen in the water then set the stage for even more complex life forms to emerge, such as the first predatory animals with guts that started to eat one another, marking the beginning of a modern marine ecosystem, with the type of food webs we are familiar with today.

It is widely accepted that the first terrestrial animals evolved from marine species. Mammals, including humans, are a class of animals that evolved from terrestrial species.

The jump from sponges to humans is, of course, a long one, but many researchers believe that sponges are the most likely candidate for an “Animal Eve,” referring to a single group of organisms that, through many stages of evolution, gave rise to all animals alive today.

Read more at Discovery News

In grasslands remade by humans, animals may protect biodiversity: Grazers let in the light, rescue imperiled plants

A comparative study of grasslands on six continents suggests there may be a way to counteract the human-made overdose of fertilizer that threatens to permanently alter the biodiversity of the world's native prairies.

The solution is one that nature devised: let grazing animals crop the excess growth of fast growing grasses that can out-compete native plants in an over-fertilized world. And grazing works in a way that is also natural and simple. The herbivores, or grazing and browsing animals, feed on tall grasses that block sunlight from reaching the ground, making the light available to other plants.

That's the key finding of a five-year study carried out at 40 different sites around the world and scheduled for online publication March 9, 2014 in the journal Nature. More than 50 scientists belonging to the Nutrient Network, a team of scientists studying grasslands worldwide, co-authored the study.

"This study has tremendous significance because human activities are changing grasslands everywhere," said study co-author Daniel S. Gruner, associate professor of entomology at the University of Maryland. "We're over-fertilizing them, and we're adding and subtracting herbivores. We have a worldwide experiment going on, but it's completely uncontrolled."

Gruner, a member of the Nutrient Network (which participants have nicknamed NutNet) since its founding in 2006, helped plan the worldwide study and analyze its results. Elizabeth Borer of the University of Minnesota was the study's lead author.

The U.N. Food and Agricultural Organization estimates that grasslands cover between one-fifth and two-fifths of the planet's land area and are home to more than one-tenth of humankind. But like all plant communities, grasslands are suffering from too much fertilizer.

As humans burn fossil fuels, dose crops with chemical fertilizers, and dispose of manure from livestock, they introduce extra nitrogen and other nutrients into the soil, air and water. The excess is a special problem for grasslands, where many plants, like annual wildflowers and others, have adapted to low nutrient levels. They often struggle to compete against grasses that use the extra nutrients to grow faster and bigger.

At the same time, grasslands worldwide are being converted to pastures for domestic animals, with native grazers like elk and antelope giving way to cattle and sheep.

Ecological theory asserts that grazers can counteract the effects of over-fertilizing in most cases, but the theory has never been broadly tested, Gruner said. To do that, the NutNet scientists ran essentially the same experiment worldwide, marking off test plots in groups of four at each of 40 sites. In each group, one plot was fenced to keep grazing animals out. One was treated with a set dose of fertilizers, to mimic the effect of excess nutrients from human sources, but was not fenced so the animals could graze. One was both fenced and fertilized. And one was left alone.

The researchers did not try to alter the test sites' animal populations. In some places native animals were abundant. At others they'd been mostly replaced by domestic animals like cattle, goats and sheep. And still others were former pastures where livestock had browsed in the past, but were no longer there.

In general, where fertilizer was added and grazing animals were kept out, the variety of plants in the experimental plots decreased. Where animals were allowed to graze in the fertilized plots, plant diversity generally increased. The researchers' data analysis concluded that the grazers improved biodiversity by increasing the amount of light reaching ground level.

Grassland plants have evolved a variety of strategies to take advantage of a setting where nutrients are in short supply and inconsistently available. They may be ground-hugging, or ephemeral, or shoot up when they capture a nutrient pulse, Gruner explained. These differing strategies create a diverse grassland ecosystem.

In the human-altered world where nutrients are always plentiful, plants that put their effort into growing tall to capture sunlight have an advantage. They block the sunlight from reaching most other plant species, which cannot grow or reproduce. But grazing animals cut down the light-blocking plants and give the others a chance to bloom.

Read more at Science Daily