May 6, 2017

A lot of galaxies need guarding

Like the quirky characters in the upcoming film Guardians of the Galaxy Vol. 2, NASA's Hubble Space Telescope has some amazing superpowers, specifically when it comes to observing galaxies across time and space. One stunning example is galaxy cluster Abell 370, which contains a vast assortment of several hundred galaxies tied together by the mutual pull of gravity. That's a lot of galaxies to be guarding, and just in this one cluster! Photographed in a combination of visible and near-infrared light with the Hubble's Advanced Camera for Surveys and Wide Field Camera 3 in Sept. 2009 to Feb. 2015, the immense cluster is a rich mix of galaxy shapes. Entangled among the galaxies are mysterious-looking arcs of blue light. These are actually distorted images of remote galaxies behind the cluster. These far-flung galaxies are too faint for Hubble to see directly. Instead, the gravity of the cluster acts as a huge lens in space, magnifying and stretching images of background galaxies like a funhouse mirror. Abell 370 is located approximately 4 billion light-years away in the constellation Cetus, the Sea Monster. It is the last of six galaxy clusters imaged in the recently concluded Frontier Fields project -- an ambitious, community-developed collaboration among NASA's Great Observatories and other telescopes that harnessed the power of massive galaxy clusters and probed the earliest stages of galaxy development.
Much like the eclectic group of space rebels in the upcoming film Guardians of the Galaxy Vol. 2, NASA's Hubble Space Telescope has some amazing superpowers, specifically when it comes to observing innumerable galaxies flung across time and space.

A stunning example is a galaxy cluster called Abell 370 that contains an astounding assortment of several hundred galaxies tied together by the mutual pull of gravity. That's a lot of galaxies to be guarding, and just in this one cluster!

Photographed in a combination of visible and near-infrared light, the immense cluster is a rich mix of galaxy shapes. The brightest and largest galaxies in the cluster are the yellow-white, massive, elliptical galaxies containing many hundreds of billions of stars each. Spiral galaxies -- like our Milky Way -- have younger populations of stars and are bluish.

Entangled among the galaxies are mysterious-looking arcs of blue light. These are actually distorted images of remote galaxies behind the cluster. These far-flung galaxies are too faint for Hubble to see directly. Instead, the cluster acts as a huge lens in space that magnifies and stretches images of background galaxies like a funhouse mirror. The massive gravitational field of the foreground cluster produces this phenomenon. The collective gravity of all the stars and other matter trapped inside the cluster warps space and affects light traveling through the cluster, toward Earth.

Nearly a hundred distant galaxies have multiple images caused by the lensing effect. The most stunning example is "the Dragon," an extended feature that is probably several duplicated images of a single background spiral galaxy stretched along an arc.

Astronomers chose Abell 370 as a target for Hubble because its gravitational lensing effects can be used for probing remote galaxies that inhabited the early universe.

Abell 370 is located approximately 4 billion light-years away in the constellation Cetus, the Sea Monster. It is the last of six galaxy clusters imaged in the recently concluded Frontier Fields project. This ambitious, community-developed collaboration among NASA's Great Observatories and other telescopes harnessed the power of massive galaxy clusters and probed the earliest stages of galaxy development. The program reveals galaxies that are 10 to 100 times fainter than any previously observed.

From Science Daily

Battered Earth revived by mineral weathering after mass extinction

Bedrock of Earth got severely beaten up by hothouse climate conditions during one of planet’s mass extinctions some 200 million years ago. But the process also allowed life to bounce back.

One of the Big Five mass extinction events occurred some 200 million years ago. Giant volcanic eruptions and an asteroid impact have been blamed for causing the disastrous change of climate, killing off nearly half of the species on Earth. 

The time epoch is called late Triassic. Amounts of carbon dioxide released through the volcanic activity during this time were staggering. Concentrations of CO2 in the atmosphere were up to 1000 ppm or so due to the volcanic activities of the period. For comparison, we have just recently reached 410 ppm of CO2 in the atmosphere today, a concentration that worries many scientists.

“In addition to the warming effects of the CO2 release, dissociation of massive amounts of methane hydrates had intensified the warming effect during the mass extinction. “ says Jochen Knies of CAGE and Geological Survey of Norway. He is a coauthor on recent Nature Communication study that has found evidence of impact of hothouse climate conditions of the late Triassic in Scandinavia.

Precisely dating deeply impacted bedrock

Published in Nature Communications by Ola Fredin (Geological Survey of Norway) and colleagues, these new findings shed light on how high greenhouse gas concentrations caused the bedrock to disintegrate through chemical weathering. Chemical weathering is caused by water reacting with the mineral grains in rocks to form new minerals, such as clay mineral illite. These reactions occur particularly when the water is acidic, as is the case when the CO2 levels are high.

“We have managed to precisely date deeply weathered crystalline bedrock from the North Sea and across Scandinavia, which then was part of the supercontinent Pangea. We did this by detailed geomorphological and mineralogical analyses of weathered rocks combined with the dating of clay mineral illite”, says Knies.

All the dated samples show that intensive and widespread chemical weathering occurred under hothouse conditions during the late Triassic. The bedrock was slowly transformed, and the transformation co-occurred with emerging volcanic activity.

Bedrock eventually removes CO2

The hothouse conditions of this mass extinction caused oceans to eventually become depleted of oxygen, and thus become unbearable to live in. But weathering of silicate in the bedrock of Pangea, and subsequent formation of carbonate, tied up the CO2 into the minerals, slowly removing the greenhouse gas from the atmosphere.

Read more at Science Daily

May 5, 2017

Noise created by humans is pervasive in US protected areas

This is an acoustic recording station at the iconic tourist attraction Alcatraz Island in San Francisco Bay, Golden Gate National Park, California.
Protected areas in the United States, representing 14 percent of the land mass, provide places for respite, recreation, and natural resource conservation. However, noise pollution poses novel threats to these protected areas, according to a first-of-its-kind study from scientists at Colorado State University and the U.S. National Park Service.

Researchers found that noise pollution was twice as high as background sound levels in a majority of U.S. protected areas, and caused a ten-fold or greater increase in noise pollution in 21 percent of protected areas.

The often-overlooked impacts of noise, driven by expansion of human activities and transportation networks, are encroaching into the furthest reaches of remote areas, according to the study. The research findings highlight the pervasiveness and identify the primary drivers of noise in protected areas.

Rachel Buxton, lead author and post-doctoral researcher in the Department of Fish, Wildlife, and Conservation Biology in the Warner College of Natural Resources, said the team was surprised by how prevalent noise pollution was in protected areas.

"The noise levels we found can be harmful to visitor experiences in these areas, and can be harmful to human health, and to wildlife," she said. "However, we were also encouraged to see that many large wilderness areas have sound levels that are close to natural levels. Protecting these important natural acoustic resources as development and land conversion progresses is critical if we want to preserve the character of protected areas."

Anthropogenic, or human-caused, noise is an unwanted or inappropriate sound created by humans, such as sounds emanating from aircraft, highways, industrial, or residential sources. Noise pollution is noise that interferes with normal activities, such as sleeping and conversation. It can also diminish a person's quality of life.

Measuring noise pollution is a challenging task, given its diffusive nature and since sound is not easily monitored remotely over large spatial scales; it can't be measured by satellite or other visual observations. Instead, for this study, the team analyzed millions of hours of sound measurements from 492 sites around the continental U.S. The results summarized predictions of existing sound levels, estimates of natural sound levels, and the amount that anthropogenic noise raises levels above natural levels, which is considered noise pollution.

How prevalent is noise pollution in protected areas? The research team found anthropogenic noise doubled background sound levels in 63 percent of U.S. protected areas, and caused a ten-fold or greater increase in background levels in 21 percent of protected areas.

In other words, noise reduced the area that natural sounds can be heard by 50 to 90 percent. This also means that what could be heard at 100 feet away could only be heard from 10 to 50 feet.

This reduced capacity to hear natural sound reduces the restorative properties of spending time in nature, such as mood enhancement and stress reduction, interfering with the enjoyment typically experienced by park visitors. Noise pollution also negatively impacts wildlife by distracting or scaring animals, and can result in changes in species composition.

High levels of noise pollution were also found in critical habitat for endangered species, namely in endangered plant and insect habitats. "Although plants can't hear, many animals that disperse seeds or pollinate flowers can hear, and are known to be affected by noise, resulting in indirect impacts on plants," said Buxton.

The study also revealed that high noise pollution levels within protected areas were in specific locations, where noise reduction techniques may best be targeted. The biggest noise-causing culprits were roads, aircraft, human development, and resource extraction.

Some protected areas have introduced effective techniques to reduce noise, launching shuttle services to cut back on traffic, implementing quiet zones where visitors are encouraged to quietly enjoy protected area surroundings, and creating noise corridors, aligning flight patterns over roads.

"Numerous noise mitigation strategies have been successfully developed and implemented, so we already have the knowledge needed to address noise issues," said George Wittemyer, an associate professor at Colorado State University and the senior author of the study. "Our work provides information to facilitate such efforts in respect to protected areas where natural sounds are integral."

Read more at Science Daily

New theory on how Earth's crust was created

Conventional theory holds that all of the early Earth's crustal ingredients were formed by volcanic activity. Now, however, earth scientists have put forth a theory with a novel twist: some of the chemical components of this material settled onto Earth's early surface from the steamy atmosphere that prevailed at the time.
More than 90% of Earth's continental crust is made up of silica-rich minerals, such as feldspar and quartz. But where did this silica-enriched material come from? And could it provide a clue in the search for life on other planets?

Conventional theory holds that all of the early Earth's crustal ingredients were formed by volcanic activity. Now, however, McGill University earth scientists Don Baker and Kassandra Sofonio have published a theory with a novel twist: some of the chemical components of this material settled onto Earth's early surface from the steamy atmosphere that prevailed at the time.

First, a bit of ancient geochemical history: Scientists believe that a Mars-sized planetoid plowed into the proto-Earth around 4.5 billion years ago, melting the Earth and turning it into an ocean of magma. In the wake of that impact -- which also created enough debris to form the moon -- the Earth's surface gradually cooled until it was more or less solid. Baker's new theory, like the conventional one, is based on that premise.

The atmosphere following that collision, however, consisted of high-temperature steam that dissolved rocks on the Earth's immediate surface -- "much like how sugar is dissolved in coffee," Baker explains. This is where the new wrinkle comes in. "These dissolved minerals rose to the upper atmosphere and cooled off, and then these silicate materials that were dissolved at the surface would start to separate out and fall back to Earth in what we call a silicate rain."

To test this theory, Baker and co-author Kassandra Sofonio, a McGill undergraduate research assistant, spent months developing a series of laboratory experiments designed to mimic the steamy conditions on early Earth. A mixture of bulk silicate earth materials and water was melted in air at 1,550 degrees Celsius, then ground to a powder. Small amounts of the powder, along with water, were then enclosed in gold palladium capsules, placed in a pressure vessel and heated to about 727 degrees Celsius and 100 times Earth's surface pressure to simulate conditions in the Earth's atmosphere about 1 million years after the moon-forming impact. After each experiment, samples were rapidly quenched and the material that had been dissolved in the high temperature steam analyzed.

The experiments were guided by other scientists' previous experiments on rock-water interactions at high pressures, and by the McGill team's own preliminary calculations, Baker notes. Even so, "we were surprised by the similarity of the dissolved silicate material produced by the experiments" to that found in the Earth's crust.

Their resulting paper, published in the journal Earth and Planetary Science Letters, posits a new theory of "aerial metasomatism" -- a term coined by Sofonio to describe the process by which silica minerals condensed and fell back to earth over about a million years, producing some of the earliest rock specimens known today.

"Our experiment shows the chemistry of this process," and could provide scientists with important clues as to which exoplanets might have the capacity to harbor life Baker says.

Read more at Science Daily

Climate Change-Driven Extinction of Alpine Plant Species May Go Undetected

Researchers working in the Austrian Alps warn that current models may be missing the impending extinction of alpine plants that are unable to migrate from or adapt to a warming climate.

While current models tend to look for the mere presence or absence of a plant species as the primary indicator of how well they are adapting to changing climate conditions, a team of scientists at the University of Zurich say that they’re missing important data — namely, the density and age structure of these populations.

“For now, presence or absence at a given location has been the model, but even if you have the presence of the species, it may be doing quite badly,” said evolutionary biologist Frédéric Guillaume, who led the study published today in Nature Communications. 

Guillaume and his team have developed a model that they hope will address this problem, specifically for alpine species that face a unique risk of extinction. Given the inherent limits to their range — constrained to pyramid-shaped mountaintops — and the longevity of alpine plants, they are particularly ill equipped to evolve to warming conditions.

Of particular concern is the age structure of alpine species, which are highly endemic and considered especially vulnerable to climate change. Much like an aging human population, the three alpine flower species and one alpine grass species targeted in the study are failing to produce viable replacements for the aging plants, creating what authors refer to as an “extinction debt.”

“The adults are adapted to a climate of the past, while juveniles must adapt to a new climate,” Guillaume explained. “By producing offspring with genes that were selected in a previous environment, they have a handicap evolving to the current environment.”

If a critical number of juvenile plants don’t take root, the population thins and faces a “demographic deficit” that could eventually lead to its extinction. And because the alpine species included in the study live for a long time, they will appear in current models even if the population is both aging and thinning.

It is a challenge faced by any plant species with a small or geographically fragmented population, attributes that will make its evolution or adaptation to a changing climate more difficult. In the Alps, this scenario is further compounded by the fact that for these plants, the only way to go is up. They quickly run out of space and options.

In the best case scenarios put forth by scientists — that warming will be limited to 1 degree Celsius compared to pre-Industrial Age levels — these populations could recover, so long as the warming slows after 2090, according to authors. But, if climate change continues unabated, alpine plants could face mass extinction.

What’s more, it could be a problem that will go undetected until it's too late, as current models cannot see what authors describe as the “invisible extinction debt.”

Read more at Discovery News

TRAPPIST-1 Planets Have No Large Moons, Study Argues

Artist's impression of a hypothetical exomoon going around an imagined planet. Exomoons have not been discovered yet, but we know of thousands of exoplanet candidates.
While we know of thousands of exoplanets and exoplanet candidates, the search for moons outside of our solar system is just beginning. We don't have a confirmed exomoon discovery yet, but they're bound to be out there.

Finding exomoons will help us better understand habitability on Earth. Some experts say a reason that life arose is our own moon is so close to the size of our planet, which stabilized its axis rotation. However, other studies (such as this 2011 American Astronomical Society paper quoted in a NASA Astrobiology story) argue that the gravitational influence of other planets in our solar system provide enough stability.

A new study looks at the possibilities of large moons in TRAPPIST-1, a notoriously crowded exoplanet system that may have habitable planets within it. Earlier this year, observations from NASA's Spitzer Space Telescope indicated that seven planets here could be rocky and have liquid water on their surfaces, making TRAPPIST-1 the system with the most potentially habitable planets.

But even before NASA's discovery, TRAPPIST-1 was known and pondered by scientists, including the author of the new paper, Stephen Kane, an associate professor of astronomy at San Francisco State University who specializes in exoplanets.

"I have several publications now on exomoons, and for many years I've been thinking about how the ability of a planet to host a moon scales with the presence of nearby planets and proximity to the host star," Kane said in an e-mail. "The discovery of the TRAPPIST-1 system prompted me to finally calculate whether or not planets in compact planetary systems can actually harbor moons."

Artist's impression of the TRAPPIST-1 system, located about 40 light-years from Earth.
Kane cautioned that scientists can't overly attribute Earth's habitability to our moon, because Earth is the only known habitable planet. However, the moon does have an important role: It creates significant tides on Earth, which probably helped create the tidal pools in which early biochemistry could occur.

"The presence of the moon has helped to stabilize changes in the tilt of the Earth's rotational axis, which in turn creates longer periods of climate stability," Kane added. "So although it's difficult to say what the Earth would be like without a moon, we can certainly describe ways in which it has positively influenced our present environment."

For TRAPPIST-1, Kane found that the planets are so tightly packed together that large moons would likely be impossible. While the rotational axes of the planets would quickly change and have more chaotic climates, he said, life could still evolve — it just might take a longer time.

Kane's methodology involved studying the influences of two parameters: the Hill radius, or the area in space in which a planet exerts gravitational influence based on its mass and distance from the host star, and the Roche limit, which identifies where the gravitational effect near a planet is too strong for a moon to survive.

Read more at Discovery News

May 4, 2017

Oldest orchid fossil on record identified

A fungus gnat trapped in amber some 45-55 million years ago is carrying on the upper portion of its severed leg a pollen sac from an orchid -- the oldest evidence of the flower ever discovered.
The orchid family has some 28,000 species -- more than double the number of bird species and quadruple the mammal species. As it turns out, they've also been around for a while.

A newly published study documents evidence of an orchid fossil trapped in Baltic amber that dates back some 45 million years to 55 million years ago, shattering the previous record for an orchid fossil found in Dominican amber some 20-30 million years old.

Results of the discovery have just been published in the Botanical Journal of the Linnean Society.

"It wasn't until a few years ago that we even had evidence of ancient orchids because there wasn't anything preserved in the fossil record," said George Poinar, Jr., a professor emeritus of entomology in the College of Science at Oregon State University and lead author on the study. "But now we're beginning to locate pollen evidence associated with insects trapped in amber, opening the door to some new discoveries."

Orchids have their pollen in small sac-like structures called pollinia, which are attached by supports to viscidia, or adhesive pads, that can stick to the various body parts of pollinating insects, including bees, beetles, flies and gnats. The entire pollination unit is known as a pollinarium.

In this study, a small female fungus gnat was carrying the pollinaria of an extinct species of orchid when it became trapped in amber more than 45 million years ago. The pollinaria was attached to the base of the gnat's hind leg. Amber preserves fossils so well that the researchers could identify a droplet of congealed blood at the tip of the gnat's leg, which had been broken off shortly before it was entombed in amber.

At the time, all of the continents hadn't even yet drifted apart.

The fossil shows that orchids were well-established in the Eocene and it is likely that lineages extended back into the Cretaceous period. Until such forms are discovered, the present specimen provides a minimum date that can be used in future studies determining the evolutionary history and phylogeny of the orchids.

How the orchid pollen in this study ended up attached to the fungus gnat and eventually entombed in amber from near the Baltic Sea in northern Europe is a matter of speculation. But, Poinar says, orchids have evolved a surprisingly sophisticated system to draw in pollinating insects, which may have led to the gnat's demise.

"We probably shouldn't say this about a plant," Poinar said with a laugh, "but orchids are very smart. They've developed ways to attract little flies and most of the rewards they offer are based on deception."

Orchids use color, odor and the allure of nectar to draw in potential pollinating insects. Orchids will emit a scent that suggests to hungry insects the promise of food, but after entering the flower they will learn that the promise of nourishment was false.

Likewise, female gnats may pick up a mushroom-like odor from many orchids, which attracts them as a place to lay their eggs because the decaying fungal tissue is a source of future nutrition. Alas, again it is a ruse. In frustration, they may go ahead and lay their eggs, dooming their offspring to a likely death from a lack of food.

Finally, male insects are attracted by the ersatz scent of female flies and they actually will attempt to copulate with a part of the orchid they think is a potential mate.

Read more at Science Daily

A first-ever find in Egypt: 4,000-year-old funerary garden at tomb entrance

This is a funerary garden discovered by CSIC's research team.
The Djehuty Project, led by research professor, José Manuel Galán, from the Spanish National Research Council (CSIC), has discovered a 4,000-year-old funerary garden- the first such garden ever to be found- on the Dra Abu el-Naga hill in Luxor, Egypt. The discovery comes during the 16th year of archaeological excavations which are sponsored this year by Técnicas Reunidas and Indra.

The discoveries made by this project shed light on a key epoch when, for the first time, Thebes (now Luxor) became the capital of the unified kingdom of Upper and Lower Egypt about 4,000 years ago.

Dr. Jose Galán explains, "We knew of the possible existence of these gardens since they appear in illustrations both at the entrances to tombs as well as on tomb walls, where Egyptians would depict how they wanted their funerals to be. The garden itself consisted of a small rectangular area, raised half a meter off the ground and divided into 30 cm2 beds. In addition, next to the garden, two trees were planted. This is the first time that a physical garden has ever been found, and it is therefore the first time that archaeology can confirm what had been deduced from iconography. The discovery and thorough analysis of the garden will provide valuable information about both the botany and the environmental conditions of ancient Thebes, of Luxor 4,000 years ago."

Galán continues, "The plants grown there would have had a symbolic meaning and may have played a role in funerary rituals. Therefore, the garden will also provide information about religious beliefs and practices as well as the culture and society at the time of the Twelfth Dynasty when Thebes became the capital of the unified kingdom of Upper and Lower Egypt for the first time. We know that palm, sycamore and Persea trees were associated with the deceased's power of resurrection. Similarly, plants such as the lettuce had connotations with fertility and therefore a return to life. Now we must wait to see what plants we can identify by analysing the seeds we have collected. It is a spectacular and quite unique find which opens up multiple avenues of research."

"Digging in a necropolis not only allows us to discover details about the world of funerals, religious beliefs and funerary practices, it also helps us discover details about daily life, about society and about the physical environment, both plant and animal. The necropolis thus becomes, as the ancient Egyptians themselves believed, the best way to understand and embrace life," concludes the CSIC researcher.

The garden, or funeral garden, was unearthed in an open courtyard at the entrance of a Middle Kingdom rock-cut tomb very probably from the Twelfth Dynasty, circa 2000 BCE. The garden, measuring 3m x 2m, is raised and is divided into a grid arrangement of 30 cm2 beds distributed in rows of five or seven beds.

According to experts, these small beds may have contained different types of plants and flowers. In addition, at the centre of the raised garden there two beds which are set higher than the others where small trees or shrubs probably grew.

In one corner, the researchers recovered a still upright tamarisk shrub complete with its roots and 30cm-long trunk, beside which was a bowl containing dates and other fruit which may have been given as an offering.

In addition, attached to the facade of the tomb, which the garden is related to for the time being, a small mud-brick chapel (46cm high x 70cm wide x 55cm deep) with three stelae, or stone tombstones, in its interior was also uncovered. These are dated later than the tomb and the garden, coming from the Thirteenth Dynasty, around the year 1800 BCE. One of them belongs to Renef-seneb, and the other to "the soldier ("citizen") Khememi, the son of the lady of the house, Satidenu." On each, reference is made to Montu, a local god from ancient Thebes, and to the funerary gods Ptah, Sokar and Osiris.

Read more at Science Daily

'Last African dinosaur' discovered in Moroccan mine

This is a Chenanisaurus barbaricus.
One of the last dinosaurs living in Africa before their extinction 66 million years ago has been discovered in a phosphate mine in northern Morocco. A study of the fossil, led by the Milner Centre for Evolution at the University of Bath, suggests that following the breakup of the supercontinent Gondwana in the middle of the Cretaceous period, a distinct dinosaur fauna evolved in Africa.

  • The new species, Chenanisaurus barbaricus, was of one of the last dinosaurs on Earth and among those species wiped out when an asteroid hit 66 million years ago
  • It is the smaller African contemporary of the North American T. rex
  • Fossil is evidence of distinct fauna in southern hemisphere at this time

Almost nothing is known about the dinosaurs that lived in Africa at the end of the Cretaceous period 66 million years ago, just before they were wiped out by the impact of a giant asteroid. At this time sea levels were high, and so most of the fossils come from marine rocks.

Among these are the phosphate deposits of Morocco -- remains of an ancient seabed, laid down 66 million years ago. The phosphate is harvested from vast strip mines and is used in everything from fertilizer to cola drinks.

Last year, Dr Nick Longrich, from the Milner Centre for Evolution and the Department of Biology & Biochemistry at the University of Bath, studied a rare fragment of a jaw bone that was discovered in the mines at Sidi Chennane in the Oulad Abdoun Basin, Morocco. In collaboration with colleagues based in Morocco, France, and Spain, Longrich identified it as belonging to an abelisaur.

Abelisaurs were two-legged predators like T. rex and other tyrannosaurs, but with a shorter, blunter snout, and even tinier arms. While the tyrannosaurs dominated in North America and Asia, the abelisaurs were the top predators at the end of the Cretaceous in Africa, South America, India, and Europe.

Dr Longrich explained: "This find was unusual because it's a dinosaur from marine rocks -- it's a bit like hunting for fossil whales, and finding a fossil lion. It's an incredibly rare find -- almost like winning the lottery. But the phosphate mines are so rich, it's like buying a million lottery tickets, so we actually have a chance to find rare dinosaurs like this one."

"We have virtually no dinosaur fossils from this time period in Morocco -- it may even be the first dinosaur named from the end-Cretaceous in Africa. It's also one of the last dinosaurs in Africa before the mass extinction that wiped out the dinosaurs.

"It's an exciting find because it shows just how different the fauna was in the Southern hemisphere at this time."

Named Chenanisaurus barbaricus, the newly discovered dinosaur stood on two legs and had stumpy arms. Dr Longrich added: "Abelisaurs had very short arms. The upper arm bone is short, the lower arm is shorter, and they have tiny little hands."

The teeth from the fossil were worn as if from biting into bone, suggesting that like T. rex, Chenanisaurus was a predator. However, unlike the partially feathered T. rex, Chenanisaurus had only scales, its brain was smaller, and its face was shorter and deeper.

Read more at Science Daily

Video Shows Cassini's View During First Saturn Ring Dive

An amazing new video shows just what NASA's Cassini spacecraft saw during its first "Grand Finale" plunge between Saturn's cloud tops and the gas giant's rings last week.

The new Saturn dive video captures about an hour of Cassini observations on April 26, starting near the planet's north polar vortex, and the bizarre hexagonal jet stream that surrounds it, and heading south from there.

"I was surprised to see so many sharp edges along the hexagon's outer boundary and the eye-wall of the polar vortex," Cassini imaging team associate Kunio Sayanagi, who's based at Hampton University in Virginia, said in a statement.

"Something must be keeping different latitudes from mixing to maintain those edges," added Sayanagi, who helped produce the new video.

The view shifts over the course of the dive video in several different ways. For example, Cassini gets closer to Saturn's cloud tops, dropping in altitude from 45,000 miles to 4,200 miles (72,400 to 6,700 kilometers). As a result, image resolution changes from 5.4 miles (8.7 km) per pixel to 0.5 mile (0.8 km) per pixel, NASA officials said.

In addition, near the end of the movie, "the camera frame rotates as the spacecraft reorients to point its large, saucer-shaped antenna in the direction of the spacecraft’s motion," NASA officials wrote in the same statement. "The antenna was used as a protective shield during the crossing of Saturn's ring plane."

That shield didn't end up taking very many hits; Cassini's first dive revealed that the narrow gap between Saturn and its innermost rings is surprisingly empty.

The $3.2 billion Cassini-Huygens mission — a joint effort of NASA, the European Space Agency and the Italian Space Agency — launched in October 1997 and reached the Saturn system in July 2004. (Huygens was a lander that the Cassini mothership helped deliver to the surface of the ringed planet's largest moon, Titan, in January 2005.)

The Cassini orbiter is almost out of fuel, so mission controllers are leading the probe through its last few months of life. This Grand Finale phase consists of 22 daring dives through the Saturn rings' gap, with each one coming about 6.5 days after the last.

The first plunge occurred on April 26 and the second on Tuesday night (May 2). The third one will take place in the early morning hours of May 9 EDT.

There is still a lot more to be learned from these additional dives, mission team members said.

Read more at Discovery News

‘Excess’ Gamma-Rays at Milky Way’s Core Likely From Pulsars, Not Dark Matter

An excess of gamma-rays coming from the center of the Milky Way is likely due to a population of pulsars – rapidly spinning, very dense and highly magnetized neutron stars that emit “beams” of gamma rays like cosmic lighthouses. The pulsars’ location in the oldest region of the galaxy suggests that they leach energy from companion stars, which prolongs the pulsars’ lifetime. The background image shows the galactic center as seen by NASA’s Chandra X-ray Observatory.
A promising lead about the nature of elusive dark matter may have just dried up.

A mysterious abundance of gamma-rays — the highest-energy light in the universe — at the Milky Way's center is likely being produced by fast-spinning stellar corpses called pulsars, rather than bits of dark matter slamming into each other, a new study suggests.

"Our study shows that we don’t need dark matter to understand the gamma-ray emissions of our galaxy,” co-author Mattia Di Mauro, from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) in California, said in a statement.

"Instead, we have identified a population of pulsars in the region around the galactic center, which sheds new light on the formation history of the Milky Way," added Di Mauro, who led the analysis for the Fermi LAT Collaboration. This is a group of researchers who used the Large Area Telescope on NASA's Fermi Gamma-ray Space Telescope to study the galaxy's gamma-ray glow.

Hunting for dark matter

Though dark matter apparently neither emits nor absorbs light (hence the name), astronomers know the stuff exists; they have observed its gravity affecting the "normal" matter we can see and touch. Indeed, such work suggests that dark matter makes up about 85 percent of the material universe.

However, scientists still don't know what the mysterious stuff is. One leading hypothesis holds that dark matter is composed mostly of Weakly Interacting Massive Particles (WIMPs). Theoretical physicists think that WIMPs generate gamma-rays when they interact with each other, either via direct annihilation or the production of a fast-decaying secondary particle.

When astrophysicists model the Milky Way’s gamma-ray sources to the best of their knowledge, they are left with an excess glow at the galactic center. Some researchers have argued that the signal might hint at hypothetical dark matter particles. However, it could also have other cosmic origins.
So it was exciting when, several years ago, Fermi spotted an "excess" of gamma-rays near the Milky Way's core that astronomers said could not be explained by traditional sources such as pulsars. Process of elimination seemed to indicate that dark matter — in the form of WIMPs — was responsible.

The researchers behind such studies stressed at the time that this interpretation was tentative and in need of backing by other observations.

Pulsars the culprit?

Such confirmation has yet to materialize.

"Two recent studies by teams in the U.S. and the Netherlands have shown that the gamma-ray excess at the galactic center is speckled, not smooth as we would expect for a dark matter signal," KIPAC's Eric Charles, who contributed to the new analysis, said in the same statement.

"Those results suggest the speckles may be due to point sources that we can't see as individual sources with the LAT because the density of gamma-ray sources is very high and the diffuse glow is brightest at the galactic center," Charles added.

The new study further supports this idea, linking the speckled signal to pulsars.

"Considering that about 70 percent of all [gamma-ray] point sources in the Milky Way are pulsars, they were the most likely candidates," Di Mauro said. "But we used one of their physical properties to come to our conclusion. Pulsars have very distinct spectra — that is, their emissions vary in a specific way with the energy of the gamma-rays they emit. Using the shape of these spectra, we were able to model the glow of the galactic center correctly with a population of about 1,000 pulsars and without introducing processes that involve dark matter particles."

There are other reasons to doubt that the gamma-ray excess is being generated by dark matter, study team members said.

"If the signal were due to dark matter, we would expect to see it also at the centers of other galaxies," Seth Digel, head of KIPAC’s Fermi group, said in the same statement. "The signal should be particularly clear in dwarf galaxies orbiting the Milky Way. These galaxies have very few stars, typically don’t have pulsars and are held together because they have a lot of dark matter. However, we don't see any significant gamma-ray emissions from them."

Read more at Discovery News

May 3, 2017

Spotted skunk evolution driven by climate change, suggest researchers

Western spotted skunk.
Climate plays a key role in determining what animals can live where. And while human-induced climate change has been causing major problems for wildlife as of late, changes in Earth's climate have impacted evolution for millions of years -- offering tantalizing clues into how to protect animals facing climate change today. In a new paper in Ecology and Evolution, scientists have delved into the effects of Ice Age climate change upon the evolution of tiny, hand-standing skunks.

"By analyzing western spotted skunk DNA, we learned that Ice Age climate change played a crucial role in their evolution," says lead author Adam Ferguson, Collections Manager of Mammals at The Field Museum in Chicago and affiliate of Texas Tech University. "Over the past million years, changing climates isolated groups of spotted skunks in regions with suitable abiotic conditions, giving rise to genetic sub-divisions that we still see today."

Western spotted skunks are really stinkin' cute -- at two pounds, they're smaller than the striped Pepe Le Pew variety, their coats are an almost maze-like pattern of black and white swirls, and when they spray, they often do a hand-stand, hind legs and fluffy tail in the air as they unleash smelly chemicals to ward off predators. They're found throughout the Western US and Mexico, in a wide variety of climates -- they thrive everywhere from Oregon's temperate rainforests to the Sonoran, the hottest desert in Mexico.

There are three genetic sub-groups, called clades, of western spotted skunks. Often, clades develop when a species is split up by geography. If a species is separated by, say, a mountain range, the groups on either side of the mountain may wind up splitting off from each other genetically. However, the division of the skunks into three clades doesn't seem to have been driven solely by geographical barriers -- populations separated by mountains are more or less genetically identical. Instead, the skunks vary genetically from one historic climate region to another, due to Ice Age climate change.

"Western spotted skunks have been around for a million years, since the Pleistocene Ice Age," explains Ferguson. "During the Ice Age, western North America was mostly covered by glaciers, and there were patches of suitable climates for the skunks separated by patches of unsuitable climates. These regions are called climate refugia. When we analyzed the DNA of spotted skunks living today, we found three groups that correspond to three different climate refugia."

"That means that for spotted skunk evolution, climate change appears to have been a more important factor than geographical barriers," says Ferguson.

In the study, scientists used DNA samples from 97 skunks from a variety of regions and climates in the American Southwest. Upon sequencing the DNA, the scientists were surprised to see that the skunks split into three clades based on pockets of suitable climate present during the Pleistocene.

"Small carnivores like skunks haven't been well-studied when it comes to historical climate change," says Ferguson. "We know how small mammals like rodents respond to changing climates, and we know how bigger carnivores like wolves respond, but this study helps bridge the gap between them."

Ferguson also notes that skunks don't deserve the bad rap they get. "Skunks are a really interesting family of North American carnivores -- they're well-known, but not well-studied. And studying them comes with a cost -- they stink, even their tissues stink, and you run the risk of getting sprayed. But they're important to their ecosystems -- for example, they eat insects and rodents that damage our crops," he says.

Moreover, Ferguson says, the study can illuminate the bigger picture of biodiversity in the face of climate change -- an issue that grows increasingly relevant as human-driven climate change affects more and more of the world's animals.

"What we know about the past can inform what we expect to see in the future," says Ferguson. "Understanding these genetic subdivisions that happened as a result of changing climatic conditions can help us conserve skunks and other animals in the future."

Read more at Science Daily

Ancient meteorite impact sparked long-lived volcanic eruptions on Earth

This is a photomicrograph of a vesicular green shard from the Onaping Formation of the Sudbury impact basin.
Meteorite impacts can produce more than craters on Earth -- they can also spark volcanic activity that shapes its surface and climate by bringing up material from depth. That is the headline finding of an international team, led by geochemists from Trinity College Dublin, who discovered that large impacts can be followed by intense, long-lived, and explosive volcanic eruptions.

The team studied rocks filling one of the largest preserved impact structures on the planet, located in Sudbury (Ontario, Canada). The 'bolide' hit Earth here 1.85 billion years ago and excavated a deep basin, which was filled with melted target rocks and, later, with jumbled mixed rocks full of tiny volcanic fragments.

Not only are there volcanic fragments throughout the sequence of the 1.5 km-thick basin but they have a very distinctive angular shape, which the scientists explain resembles a 'crab claw'. Such shapes form when gas bubbles expand in molten rock that then catastrophically explodes -- a feature of violent eruptions involving water, and which can be seen under glaciers in Iceland, for example. In the crater, these took place for a long period of time after the impact, when the basin was flooded with sea water.

The key finding of the research, just published in the Journal of Geophysical Research: Planets, is that the composition of the volcanic fragments changed with time. Right after the impact, volcanism is directly related to melting of Earth's crust. However, with time, volcanism seems to have been fed by magma coming from deeper levels within Earth.

Professor of Geology and Mineralogy at Trinity, Balz Kamber, said: "This is an important finding, because it means that the magma sourcing the volcanoes was changing with time. The reason for the excitement is that the effect of large impacts on the early Earth could be more serious than previously considered."

On the early Earth there was a relatively brief period during which ca. 150 very large impacts occurred, whereas since then, only a handful have hit Earth.

Professor Kamber added: "The intense bombardment of the early Earth had destructive effects on the planet's surface but it may also have brought up material from the planet's interior, which shaped the overall structure of the planet."

The findings raise interest in topical research on similar volcanism on other planetary bodies like Mercury, Venus, Mars and the Moon. There, unlike on Earth, the lack of plate tectonics and erosion help preserve surface features, which are probed by space craft.

Read more at Science Daily

First clues about the social lives of extinct human relatives

This is the sagittal crest of a male gorilla skull.
A new study from The Australian National University (ANU) of the bony head-crests of male gorillas could provide some of the first clues about the social structures of our extinct human relatives, including how they chose their sexual partners.

The study looks at the sagittal crest, a bone ridge on the top of the skull, in four species of apes.

Lead researcher of the study Dr Katharine Balolia of the ANU School of Archaeology and Anthropology said that while the crests were long thought to develop in apes to provide extra space for the muscles used for chewing, this study indicates they could also be a form of social signalling that results from sexual selection.

"We found that for male gorillas and orangutans, it is not just chewing that drives crest formation. There is also a social element to it. For example, females prefer male gorillas with larger sagittal crests," Dr Balolia said.

Dr Balolia said the findings may provide clues to the social structures of some extinct human relatives.

"Some species of extinct human relatives have a sagittal crest," she said.

"And if sagittal crest size and social behaviour are linked in this way, then we could potentially establish that some of our extinct human relatives had a gorilla-like social system.

"This would be a first, because otherwise the human fossil record provides precious little about how our extinct relatives chose their mates."

The study used 3D scans of skull specimens and found two lines of evidence to support the finding.

"In terms of gorilla social structures, the males establish dominance shortly after their wisdom teeth emerge. We found the sagittal crest appears right after their wisdom teeth emerge, so that fits in with the timing of social dominance," she said.

"In contrast, in orangutans some males only become dominant quite late in their adult life, and the sagittal crest appears later," she said.

In addition, statistical modelling suggests that, when present, crests in gorillas and orangutans are larger than what would be expected if they were simply there to provide more space for the larger chewing muscles needed by the big males.

From Science Daily

Pinky-Sized Marine Animal Breaks Record for Ocean Filtration

Giant larvaceans, marine animals the size of a human pinky, are so fragile that nets destroy them. Scientists have therefore desired to study them in the wild, but only recently achieved the feat using a remotely operated vehicle that launched a high-tech laser and optics gadget, DeepPIV, which looks like something out of a James Bond film. Kakani Katija, who led the effort from aboard the surface vessel Rachel Carson in Monterey Bay, described what happened next.

“When we turned off the white lights and turned on the laser, there was a collective gasp in the room — we couldn’t believe what we were seeing,” said Katija, who is the principal engineer at the Monterey Bay Aquarium Research Institute.

“We could see the larvacean pumping its tail,” she continued. “We could see the interior chambers of the filters. We could see the motion of fluid in and through the house (the animal’s filtration system).”

It was then that her colleague, senior scientist Bruce Robison, shouted, “Wow! We’re pulling back the veil of ignorance.”

Doing so revealed that a giant larvacean known as blue-tailed Bathochordaeus filters particles out of water faster than any other marine creature. It beats the prior record holder, plankton called salps. The findings are reported in the journal Science Advances.

MBARI’s MiniROV with its DeepPIV system undergoing trials in a test tank. Bubbles in the water in front of the ROV are illuminated by a sheet of light from the laser at lower left.
Giant larvaceans, a type of zooplankton, are the key to the so-called biological pump. This is a process whereby organisms in the ocean transport carbon from the atmosphere into the deep sea, where some of that carbon is sequestered.

Capturing and sequestering carbon help to mitigate global climate change, so we and every other species on the planet benefit from the ocean filtration talents of these tiny creatures every day of our lives.

“We have estimated that as much as a quarter of the organic carbon transported to the deep bottom of Monterey Bay comes from discarded giant larvacean houses,” Robison said, adding that giant larvaceans are also located in oceans across the world.

He and Katija explained that giant larvaceans first make the rudimentary filtration “house” by excreting mucus from a series of cells located on its head.

“At some point in the build process, the larvacean starts moving its tail in a specific fashion, where we suspect the animal is forcing fluid through the house rudiment, and effectively blows up the rudiment like a balloon,” Katija said.

The house is then ready for action, filtering phytoplankton and other organic particles. These materials stick in the mucus house for digestion. When the filtration system fills up with waste matter, the entire nutrient-rich house is discarded and sinks to the sea floor. There, it provides a source of food for deep-sea animals. Giant larvaceans at that point may swim to another location, prior to building another house, in order to start the process all over again.

The animals have such an effective filtration system that researchers have even considered adding them to the ocean to do more good work. That idea was shut down quickly, however, due to concerns over unintended consequences, such as disruption of the marine ecosystem.

Robison said scientists of the past learned hard lessons about unintended consequences. He then listed some of the colossal failures: bringing mongooses to Hawaii to control rats in sugar cane fields (mongooses became an invasive species there); dumping radioactive waste in the ocean (causing pollution and hurting marine life); and bringing kudzu plants from Japan into the states to feed livestock (kudzu became an invasive species).

Read more at Discovery News

New Plant-Eating Dinosaur Was So Big It Had No Predators

Artistic life reconstruction of the dinosaur Galeamopus pabsti.
Carnivores were not the only animals at the top of the Jurassic food chain, suggests a newly described herbivorous dinosaur that avoided predation due to its massive size and “whiplash” tail, which is thought to have cracked like a bullwhip to create sonic booms.

The new species, Galeamopus pabsti, measured well over 66 feet long and weighed more than 15 tons. It lived 150 million years ago and is described in the journal PeerJ.

While healthy adults of this species likely had few or no predators, carnivorous dinosaurs feasted on any of these enormous, meaty animals that had already keeled over.

Emanuel Tschoop, lead author on the study, is a paleontologist at the University of Turin.

“Numerous teeth and tooth marks on the bones of the skeleton show that Allosaurus and Ceratosaurus fed on the carcass, and probably also preyed upon juveniles or sick individuals,” he told Seeker. Both Allosaurus and Ceratosaurus were large carnivorous dinosaurs.

Galeamopus pabsti in its environment in the Late Jurassic of North America. An Allosaurus and two Ceratosaurus are feeding on a carcass of Galeamopus pabsti.
Tschopp and co-author Octávio Mateus of the Universidade Nova de Lisboa and the Museum of Lourinhã in Portugal analyzed the remains of the new dinosaur, which were excavated in 1995 by paleontologist Ben Pabst and his team. Named after Pabst, the dinosaur once lived in what are now Wyoming and Colorado.

“The ecosystem in which G. pabsti lived was a huge alluvial plane, with meandering rivers that flowed from the south-west towards the north and north-east, into a relatively shallow inland sea, which covered parts of what are now Canada and Montana,” Tschopp explained.

The researchers determined that the dinosaur was a diplodocid sauropod, placing it among the most iconic dinosaurs and the longest creatures ever to walk the earth. Members of the family Diplodocidae (meaning “Double Beams”) include Diplodocus and Supersaurus, which may have reached lengths up to 112 feet.

These animals have a reputation for being dullard dinosaurs, since their brains were very small, particularly in relation to the rest of their bodies. The jury, though, is still out on how brain size affected their levels of intelligence.

Paleontologist Emanuel Tschopp and Ben Pabst with the skull of the new species dedicated to Pabst in the Sauriermuseum Aathal: Galeamopus pabsti.
It is suspected that Galeamopus pabsti spent much of its time peacefully feasting on ferns, horse-tails, and other plant materials. Animals on the ground must have mostly seen the tree trunk-like legs of these extremely large dinosaurs.

Another noteworthy feature of the newly described dinosaur is the unusual triangular shape of the part of its neck closest to its head.

“The neck was not a perfect triangle, but it was much wider at the bottom than at the top,” Tschopp said.

A very complete series of neck vertebrae were found with the remains of the dinosaur. It is therefore hoped that these fossils might solve a longstanding mystery over how sauropods held their necks.

Some researchers believe that the necks were mostly held erect, like those of a giraffe, allowing them to reach tall-growing trees and other vegetation. Still other scientists believe that the necks were held in a more horizontal position, permitting the dinosaurs to sweep over large plant food surfaces. Perhaps all of these movements were possible.

Read more at Discovery News

May 2, 2017

Earliest relative of Brachiosaurus dinosaur found in France

This Vouivria herd are roaming the coast of what is now Europe. Millions of years ago Europe was a chain of islands and, being a herbivore, Vouivria damparisensis would have grazed on the vegetation in its local vicinity.
Scientists have re-examined an overlooked museum fossil and discovered that it is the earliest known member of the titanosauriform family of dinosaurs.

The fossil, which the researchers from Imperial College London and their colleagues in Europe have named Vouivria damparisensis, has been identified as a brachiosaurid sauropod dinosaur.

The researchers suggest the age of Vouivria is around 160 million years old, making it the earliest known fossil from the titanosauriform family of dinosaurs, which includes better-known dinosaurs such as the Brachiosaurus. When the fossil was first discovered in France in the 1930s, its species was not identified, and until now it has largely been ignored in scientific literature.

The new analysis of the fossil indicates that Vouivria died at an early age, weighed around 15,000 kilograms and was over 15 metres long, which is roughly 1.5 times the size of a double-decker bus in the UK.

It had a long neck held at around a 45 degree angle, a long tail, and four legs of equal length. It would have been a plant eater.

Dr Philip Mannion, the lead author of the study from the Department of Earth Science and Engineering at Imperial College London, said: "Vouivria would have been a herbivore, eating all kinds of vegetation, such as ferns and conifers. This creature lived in the Late Jurassic, around 160 million years ago, at a time when Europe was a series of islands. We don't know what this creature died from, but millions of years later it is providing important evidence to help us understand in more detail the evolution of brachiosaurid sauropods and a much bigger group of dinosaurs that they belonged to, called titanosauriforms."

Titanosauriforms were a diverse group of sauropod dinosaurs and some of the largest creatures to have ever lived on land. They lived from at least the Late Jurassic, right to the end-Cretaceous mass extinction, when an asteroid wiped out most life on Earth.

A lack of fossil records means that it has been difficult for scientists to understand the early evolution of titanosauriforms and how they spread out across the planet. The re-classification of Vouivria as an early titanosauriform will help scientists to understand the spread of these creatures during the Early Cretaceous period, a later period of time, after the Jurassic, around 145 -- 100 million years ago.

The team's incorporation of Vouivria into a revised analysis of sauropod evolutionary relationships shows that by the Early Cretaceous period, brachiosaurids were restricted to what is now Africa and the USA, and were probably extinct in Europe.

Previously, scientists had suggested the presence of another brachiosaurid sauropod dinosaur called Padillasaurus much further afield in what is now South America, in the Early Cretaceous. However, the team's incorporation of Vouivria into the fossil timeline suggests that Padillasaurus was not a brachiosaurid, and that this group did not spread as far as South America.

The Vouivria fossil was originally discovered by palaeontologists in the village of Damparis, in the Jura Department of eastern France, in 1934. Ever since, it has been stored in the Museum National d'Histoire Naturelle, Paris. It was only briefly mentioned by scientists in studies in the 1930s and 1940s, but it was never recognised as a distinct species. It has largely been ignored in the literature, where it has often been referred to simply as the Damparis dinosaur.

Now, a deeper analysis of the fossil is also helping the scientists in today's study to understand the environment Vouivria would have been in when it died, which was debated when it was initially found. The researchers believe Vouivria died in a coastal lagoon environment, during a brief sea level decline in Europe, before being buried when sea levels increased once more. When the fossil was first discovered, in rocks that would have originally come from a coastal environment, researchers suggested that its carcass had been washed out to sea, because sauropods were animals that lived on land.

Today's team's examination of Vouivria, coupled with an analysis of the rocks it was encased in, provides strong evidence that this was not the case.

The genus name of Vouivria is derived from the old French word 'vouivre', itself from the Latin 'vipera', meaning 'viper'. In French-Comte, the region in which the specimen was originally discovered, 'la vouivre' is a legendary winged reptile. The species name damparisensis refers to the village Damparis, from which the fossil was originally found.

The research was carried out in conjunction with the Museum National d'Histoire Naturelle and the CNRS/Université Paris 1 Panthéon-Sorbonne, with funding from the European Union's Synthesys programme.

Read more at Science Daily

Nearby star is a good model of our early solar system

This is an artist's illustration of the epsilon Eridani system showing Epsilon Eridani b, right foreground, a Jupiter-mass planet orbiting its parent star at the outside edge of an asteroid belt. In the background can be seen another narrow asteroid or comet belt plus an outermost belt similar in size to our solar system's Kuiper Belt. The similarity of the structure of the Epsilon Eridani system to our solar system is remarkable, although Epsilon Eridani is much younger than our sun. SOFIA observations confirmed the existence of the asteroid belt adjacent to the orbit of the Jovian planet.
NASA's SOFIA aircraft, a 747 loaded with a 2.5-meter telescope in the back and stripped of most creature comforts in the front, took a big U-turn over the Pacific west of Mexico.

The Stratospheric Observatory for Infrared Astronomy aircraft was just beginning the second half of an overnight mission on Jan. 28, 2015. It turned north for a flight all the way to western Oregon, then back home to NASA's Armstrong Flight Research Center in Palmdale, California. Along the way, pilots steered the plane to aim the telescope at a nearby star.

Iowa State University's Massimo Marengo and other astronomers were on board to observe the mission and collect infrared data about the star.

That star is called epsilon Eridani. It's about 10 light years away from the sun. It's similar to our sun, but one-fifth the age. And astronomers believe it can tell them a lot about the development of our solar system.

Marengo, an Iowa State associate professor of physics and astronomy, and other astronomers have been studying the star and its planetary system since 2004. In a 2009 scientific paper, the astronomers used data from NASA's Spitzer Space Telescope to describe the star's disk of fine dust and debris left over from the formation of planets and the collisions of asteroids and comets. They reported the disk contained separate belts of asteroids, similar to the asteroid and Kuiper belts of our solar system.

Subsequent studies by other astronomers questioned that finding.

A new scientific paper, just published online by The Astronomical Journal, uses SOFIA and Spitzer data to confirm there are separate inner and outer disk structures. The astronomers report further studies will have to determine if the inner disk includes one or two debris belts.

Kate Su, an associate astronomer at the University of Arizona and the university's Steward Observatory, is the paper's lead author. Marengo is one of the paper's nine co-authors.

Marengo said the findings are important because they confirm epsilon Eridani is a good model of the early days of our solar system and can provide hints at how our solar system evolved.

"This star hosts a planetary system currently undergoing the same cataclysmic processes that happened to the solar system in its youth, at the time in which the moon gained most of its craters, Earth acquired the water in its oceans, and the conditions favorable for life on our planet were set," Marengo wrote in a summary of the project.

A major contributor to the new findings was data taken during that January 2015 flight of SOFIA. Marengo joined Su on the cold and noisy flight at 45,000 feet, above nearly all of the atmospheric water vapor that absorbs the infrared light that astronomers need to see planets and planetary debris.

Determining the structure of the disk was a complex effort that took several years and detailed computer modeling. The astronomers had to separate the faint emission of the disk from the much brighter light coming from the star.

"But we can now say with great confidence that there is a separation between the star's inner and outer belts," Marengo said. "There is a gap most likely created by planets. We haven't detected them yet, but I would be surprised if they are not there. Seeing them will require using the next-generation instrumentation, perhaps NASA's 6.5-meter James Webb Space Telescope scheduled for launch in October 2018."

That's a lot of time and attention on one nearby star and its debris disk. But Marengo said it really is taking astronomers back in time.

Read more at Science Daily

Our Decomposing Bodies Are Altering Earth's Chemistry

It's not only in life that humans leave their mark on nature. In death, our decomposing corpses alter the chemistry of precious soil, scientists warned on Wednesday.

Whether our bodies are buried or cremated, they leach iron, zinc, sulfur, calcium, and phosphorus into ground that might later be used as farms, forests, or parks.

They are essential nutrients, but human funerary practices mean they are being concentrated in cemeteries instead of being dispersed evenly throughout nature, according to new research.

This means that in some places the nutrients may be over-concentrated for optimal absorption by plants and creatures, while lacking in others.

Furthermore, human bodies also contain more sinister elements, such as mercury from dental fillings.

“Chemical traces of decomposed bodies can frequently be very well distinguished in soil,” said Ladislav Smejda of the Czech University of Life Sciences in Prague, who took part in the unusual probe. “These traces persist for a very long time, for centuries to millennia.”

The effects will become more pronounced as more and more dead bodies are laid to rest, Smejda said in Vienna, where he unveiled the research at a meeting of the European Geosciences Union.

“What we do today with our dead will affect the environment for a very, very long time,” he said. “Maybe it is not such a problem in our current perspective but with an increasing population globally it might become a pressing problem in the future.”

Smejda and a team used X-ray fluorescence spectroscopy to analyze soil chemicals in graves and ash “scattering gardens.”

Pushing up daisies

Using animal carcasses, they also measured the theoretical impact of an ancient practice called “excarnation”, whereby the dead are left out in the open for nature to take its course.

In all three cases, Smejda said, the ground contained “significantly” higher concentrations of chemicals compared to the surrounding areas.

If there had been no cemeteries, human remains, like those of animals, would be distributed randomly for the nutrients they release to be reused “again and again, everywhere,” the researcher told AFP.

But concentrating them in certain places, he said, “is something that can be regarded as not natural. It's a human impact, we are changing natural levels.”

Now the question, he added, is: “Can we come up with a better idea [of] how to distribute these necessary elements across wider landscapes?”

“Certainly there is a potential to invent, to develop and to put into practice... new ways of human burial or new treatments that could be more environmentally friendly, more ecological.”

Read more at Discovery News

To Unlock the Secrets of Prehistoric Hand Paintings, Experts Catalog Them in 3D

A hand painting from Maltravieso Cave in Cáceres, Spain.
It’s dark and surprisingly warm in a cave in western Spain that hides our most intimate connection to the prehistoric past — hand silhouettes painted tens of thousands of years ago.

Archaeologist Hipolito Collado and his team had not entered the Maltravieso Cave in the city of Caceres for close to a year to avoid damaging the 57 faded hands that adorn the walls, precious remnants of a far-flung piece of history we know little about.

Why did our ancestors or distant relatives paint hands in caves? Was it merely to make their mark, or part of a ritual to commune with spirits?

Do they tell us anything about the role of women during the Paleolithic era that ended some 10,000 years ago? And why are some fingers missing?

In a bid to unlock some of these mysteries, Collado, head of archaeology for the government of the Extremadura region where Caceres is located, has set out to catalog all of Europe’s prehistoric painted hands.

Crouching under low hanging rocks or abseiling down crags, he and other archaeologists have been going from cave to cave, taking scans and high-resolution photos of all the hands they encounter.

They then post them in detailed, 3D format in a free-to-use online database, as part of an EU-funded project called Handpas.

The entrance to Maltravieso Cave.
The idea is for researchers anywhere in the world to be able to examine them all in one place without having to visit every cave or gain access to those closed for conservation, in the hope of producing a breakthrough.

“It’s about making inaccessible art accessible,” said Collado, as he checks sensors for any change in CO2 levels, temperature or humidity since he last visited the meandering, cramped cave.

Surrounded by high rises in what was a poor neighborhood of Caceres, the cave was discovered in 1951 in a quarry but left neglected for decades, squatted by thrill-seekers, junkies and others until authorities put up a wrought-iron gate barring the entrance in the mid-1980s.

According to Collado, a Spaniard who is also head of the International Federation of Rock Art Organizations, painted hands have been found in 36 caves in Europe — all in France, Spain and Italy. Some also contain animal drawings and fossils but his project focuses only on hands.

Further afield, hands have also been discovered in South America, Australia and Indonesia, where recent research revealed that a hand silhouette in a cave on Sulawesi island was 40,000 years old — the world’s oldest.

That was around the time when Homo sapiens — the first modern humans — arrived in Europe after having emerged in Africa and lived in parts of Asia.

Theories abound about what the hands mean, but with no written records, much of it is conjecture.

Researchers have tried to determine whether they were male or female, and why in some cases fingers are missing.

Was this a ritual? Did they lose them in freezing cold weather? Or — as is more commonly believed — did they simply fold some fingers over when painting in some sort of sign language?

What if scientists were able to determine for certain that all hands in one area were done by women?

“It could mean a matriarchal society,” said Collado’s colleague Jose Ramon Bello Rodrigo.

And did Homo sapiens — or possibly Neanderthals before them — merely wander into a cave and casually leave their hand imprint as a form of ancient “I was here”?

Paul Pettitt, professor of Paleolithic Archaeology at Britain’s Durham University, doesn’t think so.

His research focuses on where people placed their hands and he found that in some cases, fingers appeared to be deliberately placed over a bump in the wall like they were “gripping” it.

Many hands are also in the deeper recesses of the caves.

“It must have been very frightening, it must have been quite a degree of exertion, a lot of climbing in the darkness,” said Pettitt. “You don’t do that for fun.”

Why then would people go to such lengths to paint hands onto the walls — be it via stencils, created by spraying pigment around an open hand, or actual handprints applied to the rock face?

French prehistorian Jean Clottes believes it may have been a form of shamanism.

“It’s likely that putting paint — what we could call sacred paint — on the rock face introduces a link between the person who does it and the rock face, and therefore with the forces in the rock face,” he said.

Collado also interprets some of the hands he has seen as warnings.

“In the La Garma Cave [in northern Spain] there is a panel with hands that is next to a big well that would be deadly,” he said. “These were definitely done to say ‘stop’.”

Read more at Discovery News