Detour via gravitational lens makes distant galaxy visible

Photons are emitted from a galaxy QSO B0218+357 in the direction of the Earth. Due to the gravitational effect of the intervening galaxy B0218+357G photons form two paths that reach Earth with a delay of about 11 days. Photons were observed by both the Fermi-LAT instrument and the MAGIC telescopes.

Never before have astrophysicists measured light of such high energy from a celestial object so far away. Around 7 billion years ago, a huge explosion occurred at the black hole in the center of a galaxy. This was followed by a burst of high-intensity gamma rays. A number of telescopes, MAGIC included, have succeeded in capturing this light. An added bonus: it was thus possible to reconfirm Einstein's General Theory of Relativity, as the light rays encountered a less distant galaxy en route to Earth -- and were deflected by this so-called gravitational lens.

The object QSO B0218+357 is a blazar, a specific type of black hole. Researchers now assume that there is a supermassive black hole at the center of every galaxy. Black holes, into which matter is currently plunging are called active black holes. They emit extremely bright jets. If these bursts point towards Earth, the term blazar is used.

Full moon prevents the first MAGIC observation

The event now described in "Astronomy & Astrophysics" took place 7 billion years ago, when the universe was not even half its present age. "The blazar was discovered initially on 14 July 2014 by the Large Area Telescope (LAT) of the Fermi satellite," explains Razmik Mirzoyan, scientist at the Max Planck Institute for Physics and spokesperson for the MAGIC collaboration. "The gamma ray telescopes on Earth immediately fixed their sights on the blazer in order to learn more about this object."

One of these telescopes was MAGIC, on the Canary Island of La Palma, specialized in high-energy gamma rays. It can capture photons -- light particles -- whose energy is 100 billion times higher than the photons emitted by our Sun and a thousand times higher than those measured by Fermi-LAT. The MAGIC scientists were initially out of luck, however: A full moon meant the telescope was not able to operate during the time in question.

Gravitational lens deflects ultra-high-energy photons

Eleven days later, MAGIC got a second chance, as the gamma rays emitted by QSO B0218+357 did not take the direct route to Earth: One billion years after setting off on their journey, they reached the galaxy B0218+357G. This is where Einstein's General Theory of Relativity came into play.

This states that a large mass in the universe, a galaxy, for example, deflects light of an object behind it. In addition, the light is focused as if by a gigantic optical lens -- to a distant observer, the object appears to be much brighter, but also distorted. The light beams also need different lengths of time to pass through the lens, depending on the angle of observation.

This gravitational lens was the reason that MAGIC was able, after all, to measure QSO B0218+357 -- and thus the most distant object in the high-energy gamma ray spectrum. "We knew from observations undertaken by the Fermi space telescope and radio telescopes in 2012 that the photons that took the longer route would arrive 11 days later," says Julian Sitarek (University of ?ódz, Poland), who led this study. "This was the first time we were able to observe that high-energy photons were deflected by a gravitational lens."

Read more at Science Daily

Plumage evolution: Explaining the vivid colors of birds

Close-up of the ornamental white feathers on a pair of Crescent Honeyeaters, Phylidonyris pyrrhopterus, one of the species of birds examined in this study.

During his notable trip to the Galápagos Islands, Charles Darwin collected several mockingbird specimens on different islands in the region. He later discovered that each island only contained a single species of mockingbird and no two species of mockingbird co-existed on an individual island. Due to their geographical separation, over time these birds had evolved different characteristics in coloration, behavior, and beak shape. These observations raise the question: how does a geographical region influence the evolution of a species?

Tropical birds are well known for their colorful appearance: vibrantly colored macaws, parakeets and parrots are widely considered to be the quintessential birds of this region. The popularity of these birds leads many to assume that tropical climates are home to a greater proportion of colorful birds than temperate climates. But do birds evolve to become more colorful when they move to the tropics? Research from Dr. Nicholas Friedman, who is part of the Biodiversity and Biocomplexity Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), helps answer this question.

As part of his research in collaboration with Vladimír Remeš at Palacký University in the Czech Republic, Friedman headed to Australia to examine the feathers of different birds across the country and its neighboring tropical islands to see if there was a correlation between geographical climate zone and color pattern. Australia is home to a rich mixture of species, many of which are found nowhere else. The fact that Australian species were geographically isolated from the rest of the world for so long makes it an excellent place to study evolution. A trip to Australia as a young man contributed to Charles Darwin's pivotal work on evolution, On the Origin of Species.

Friedman began his study at the Australian National Wildlife Collection, where he examined bird specimens from different regions of Australia. A total of 137 different species from two major songbird families were examined. Songbirds originated in Australia nearly 30 million years ago. Research suggests that these birds began diversifying there before colonizing other parts of the world. The familial relationships of the birds that Friedman examined were compared using an evolutionary tree based on the birds' DNA. Friedman then used a special instrument to measure the color of the feathers in particular places on the birds. Birds can see a wider range of colors than humans can, and many are even able to see colors in the UV spectrum in addition to those in the 'visible' spectrum, so the differences in color patterns between birds may appear more pronounced to birds than they appear to humans. Next, Friedman used data from satellites to describe the geographical region each species lives in. He looked at vegetation, precipitation, and humidity of each region, then combined this data with the evolutionary relationships and color measurements of the birds.

The results of this study, published in Global Ecology and Biogeography, show that bird species do not evolve more colorful feathers in the tropics compared to their cousins in temperate climates. "If you look at birds in the tropics, there are a lot of colorful birds that stand out. But there are really more species in general there, and there are just as many more of the little brown ones" describes Friedman. "Instead, birds living in the harsh arid climates of inland Australia tended to have fancier colors than those in the lush tropical islands. Since desert birds have to scramble for mates during the wet season, we think they may be evolving colors that can attract mates quickly."

Meanwhile, birds thriving in climates with more precipitation and vegetation are darker in color overall, while desert birds tend to be lighter. "The pattern is really clear" Friedman reports, "birds living in the desert tend to be more grey on their backs, while birds living in the forest have evolved to be more of a dark green -- we think they are evolving these colors to match their background." This would be an example of natural selection, in this case more camouflaged organisms can survive and pass on their genes.

Read more at Science Daily

Undiscovered Moons May Lurk in Our Own Solar System

In the 1970s and 1980s, NASA sent twin spacecraft — Voyager 1 and Voyager 2 — on a quest to explore the solar system. Both probes zoomed by Jupiter and Saturn, and Voyager 2 continued on to see Uranus and Neptune.

The spacecraft made many discoveries, including finding several moons at each system. But long after Voyager 2 left Uranus behind in 1989, and with fewer spacecraft exploring the outer solar system, we are still finding new satellites. Some, surprisingly, are from old Voyager data being reanalyzed with new techniques.

Other finds are from the venerable Hubble Space Telescope, which has been in Earth orbit since April 1990. It shows that even decades after Voyager, there are likely new moons waiting to be found -- especially with the sharper eye of the James Webb Space Telescope slated to start working in 2018.

Part of the secret appears to be the Cassini factor. Scientists have been learning a lot about ring behavior, and how satellites affect them, since the mission has been examining Saturn in 2004. Recently, scientists applied that understanding to the Uranus system, using data from Voyager obtained in 1986. They found regular patterns in the rings that suggest there could be moonlets there.

"There were some very clear periodic variations in the structure of the alpha and the beta rings," said University of Idaho physics researcher Matthew Hedman, who was a participant in the experiment led by doctoral student Rob Chancia, in an interview with Seeker. "The opacity of the ring just changed in a periodic way over a couple of kilometers. The thing that was weird about the structure was it had different wavelengths in different places. It wasn't the same kind all the way around the ring, which a lot of ring structures are."

A composite Hubble Space Telescope image showing Neptune (color) and a new moon (black and white).

The closest analog he could think of is something called a "moonlet rake." While the term sounds straight out of a James Bond movie, in reality it describes how a moon preturbs material on the other side of a ring gap. It was first described for the Encke gap, a famous gap in Saturn's outer rings.

But here's where the story stops, at least for now. Hedman and his graduate students will publish the results shortly in the Astronomical Journal in the hopes that somebody more experienced in spacecraft imaging can find moonlets. Hedman will continue investigating and comparing ring structures across the solar system, as not everything yet can be explained by moons.

One researcher who may carry the torch is a veteran moon-hunter himself. The SETI Institute's Mark Showalter was the one who first described moonlet rakes. He's been processing spacecraft images since Voyager; he was a grad student when the spacecraft passed by Saturn, and was doing his postdoctoral work during the Uranus and Neptune encounters.

Thirty years of moon-hunting came in very handy for him in 2013, when his team announced they had discovered yet another moon around Neptune, using Hubble. So how could Voyager go right past the moon and not easily find it? The camera was built on 1970s technology, and it was working in low light, Showalter said. He also found the Uranian moons Cupid and Mab (using Hubble) in 2003; one was practically invisible in Voyager data when he looked again, while the other one was barely detectable.

One of his next projects will be looking again at Uranus to see if those moonlets are there, he said. "I do have a lot of Hubble data of the Uranus system," he said in an interview. "Now that I know where to look, based on Rob and Matt's results, I do plan to do a search of the existing archive of Hubble data from Uranus for any chance to pick out these little objects."

A moon is spotted around the dwarf planet Makemake in this Hubble Space Telescope Image from April 2015.

While the thrill of discovery is what excites the public, there are more fundamental things these new moons can teach us. At Neptune, Showalter was fascinated that his tiny moon discovery in 2013 did not follow the pattern of smallest to largest moons (from the center of Neptune outward) previously discovered in the system. He noted that Neptune's system was completely changed by the capture of Triton (a very large moon) early in the solar system's history, but it's hard to know all the dynamics with the information we have so far.

Other moon mysteries lie in other parts of the solar system. When New Horizons was on its way to Pluto, the moons Styx and Kerberos were found in 2011 and 2012, respectively. Nix was also found in 2005, the year before it launched. (All three finds included researchers part of the "Pluto Companion Search Team", who were tasked specifically for New Horizons' flight.) Previously, only the moon Charon was known — discovered in 1978.

"The Pluto team is intrigued that such a small [dwarf] planet can have such a complex collection of satellites," NASA said in a 2012 statement. "The new discovery provides additional clues for unraveling how the Pluto system formed and evolved. The favored theory is that all the moons are relics of a collision between Pluto and another large Kuiper belt object billions of years ago."

Read more at Discovery News

Historic Paris Climate Pact Is Now Law

A worldwide pact to battle global warming entered into force Friday, just a week before nations reassemble to discuss how to make good on their promises to cut planet-warming greenhouse gases.

Dubbed the Paris Agreement, it's the first-ever deal binding all the world's nations, rich and poor, to a commitment to cap global warming caused mainly from the burning of coal, oil and gas.

"A historic day for the planet," said the office of President Francois Hollande of France, host to the 2015 negotiations that yielded the breakthrough pact.

"Humanity will look back on Nov. 4, 2016, as the day that countries of the world shut the door on inevitable climate disaster," UN climate chief Patricia Espinosa and Moroccan Foreign Minister Salaheddine Mezouar said in a joint statement.

Mezouar will preside over the UN meeting opening in Marrakesh on Monday.

"It is also a moment to look ahead with sober assessment and renewed will over the task ahead," they said.

This meant drastically and urgently cutting emissions, which requires political commitment and considerable financial investment.

The urgency was brought home by a UN report Thursday warning that emissions trends were steering the world towards climate "tragedy."

By 2030, said the UN Environment Programme, annual emissions will be 13 to 15 billion tons of carbon dioxide equivalent (CO2e) higher than the desired level of 46 billion tons.

The 2014 level was about 58 billion tons.

2016 is on track to become the hottest year on record, and carbon dioxide levels in the atmosphere passed an ominous milestone in 2015.

On Friday, the Eiffel Tower in Paris as well as public buildings in Marrakesh, Adelaide, Brussels, New Delhi and Sao Paulo were to be lit in green to mark the entry into force of the pact meant to stop the rot.

That historic agreement was finally endorsed in the French capital last December, after years of complex and divisive negotiations, but the ratification was reached with record speed.

At least 55 parties to the UN's climate convention (UNFCCC), responsible for at least 55 percent of global greenhouse gas emissions, had to ratify it for it to take effect.

It passed the threshold last month, and by Friday had been ratified by 97 of the 197 UNFCCC parties, representing 67.5 precent of emissions, according to France's environment minister Segolene Royal, the outgoing president of the UN talks.

'Magnificent day'

"It is a magnificent day, concluding years of hard work," Royal told journalists in Paris.

"We must maintain this extraordinary momentum by encouraging countries to continue ratifying the deal, and by moving full steam ahead with our preparations to put it into action across the world," Europe's climate commissioner Miguel Canete added in a statement.

A major doubt looms over the process, however, as diplomats gear up for 11 days of talks in Morocco to discuss way of putting the agreement's political undertakings into practice.

U.S. Republican nominee Donald Trump has threatened to "cancel" Washington's participation in the agreement if he is elected president on Nov. 8.

Read more at Discovery News

Toilet Break Discovery Rewrites Aboriginal History

The chance discovery of a rock shelter in the Flinders Ranges has unearthed one of the most important prehistoric sites in Australia.

The site, known as Warratyi, shows Aboriginal Australians settled the arid interior of the country around 49,000 years ago — some 10,000 years earlier than previously thought.

The shelter, about 550 kilometers north of Adelaide, also contains the first reliably dated evidence of human interaction with megafauna.

Artefacts excavated at the site also push back the earliest-known dates on the development of key bone and stone axe technologies and the use of ochre in Australia.

Lead author Giles Hamm, a consultant archaeologist and doctoral student at La Trobe University, found the site with local Adnyamathanha elder Clifford Coulthard while surveying gorges in the northern Flinders Ranges.

"A man getting out of the car to go to the toilet led to the discovery of one of the most important sites in Australian pre-history."

Mr Hamm said during a survey of the gorge they noticed a rock shelter with a blackened roof about 20 meters above the creek bed.

"Immediately when we saw that we thought, 'Wow, that's people lighting fires inside that rock shelter, that's human activity'," he said.

At the time they had no idea how significant the find was, Mr Hamm admitted, and thought maybe it would reach back about 5,000 years.

Working with the Adnyamathanha people over the past nine years, Mr Hamm and colleagues recovered from the one-meter-deep excavations around 4,300 artifacts and 200 bone fragments from 16 mammals and one reptile.

Importantly dating of the artifacts and fossil finds show humans occupied the site from 49,000 to 46,000 years ago.

Mr Hamm said the significance of the site was the combination of its age and geographic location.

The previous oldest-known site in the arid zone, located at Puritjarra in western Central Australia, is around 38,000 years old.

However, Mr Hamm said it was likely the climate was more favorable when they arrived.

"They got there before it became really arid," he said.

"In one sense they were trapped in the Flinders Ranges because once the climate changed [due to the last glacial maximum] it was too risky to move out of these well-watered ranges that had these permanent springs."

It was a view supported by palaeoanthropologist Michael Westaway at Griffith University, who was part of a recent genomic study that confirmed modern Aboriginal Australians are the descendants of the first people to inhabit Australia and showed they adapted genetically to survive in the desert.

"Our DNA paper suggested the arid center at 50,000 years ago was not really a barrier to the movement of people, and this seems to be what Giles is suggesting — people were able to migrate south quite quickly," Dr Westaway said.

Among the other significant artifact finds at the site was the earliest-known use of ochre in Australia and South-East Asia around 49,000-46,000 years ago.

Mr Hamm said they had pushed back the dates on the development of technologies such as bone needles (40,000-38,000 years ago), wood-handled stone tools (at least 24,000 years ago) and gypsum use (40,000-33,000 years ago).

The site also provided reliably dated evidence of hafted axe technology about 38,000 years ago.

Co-author Professor Gavin Prideaux pointed to the discovery of bones from the extinct giant wombat-like Diprotodon optatum and eggs from an ancient giant bird as important evidence of interaction with ancient humans which would have an impact on the debate over the extinction of megafauna.

Professor Prideaux, from Flinders University's School of Biological Sciences, said the only previous site in Australia where megafauna remains and human artifacts had been found together was Cuddie Springs in NSW, which had become the subject of controversy over the accuracy of dating.

"One good thing about this study ... is there's no doubt there are megafauna remains in the form of Diprotodon and a giant bird in that rock shelter in a well-dated, well-stratified context sometime between 45,000 and 50,000 years ago," Professor Prideaux said.

"The only way those bones and shells got there [because of the steep incline up to the rock shelter] is because people brought them there [to eat] ... in terms of megafauna that's the really significant finding."

Read more at Discovery News

Flood-Damaged Masterpiece Miraculously Restored

Exactly 50 years ago, on Nov. 4, 1966, the river Arno burst its banks and raced through Florence in the worst flood the city had seen in centuries.

Muddy waters rushed into my family's home as well as into the homes of thousands of Florentines. The flood came with little warning, claiming the lives of 34 people. Raging torrents entered streets, houses, shops, museums, churches and libraries.

Thousands of frescoes, paintings, sculptures and rare books were destroyed or terribly damaged by slime in one of the greatest cultural disasters of modern times.

Such was the devastation that an army of young volunteers — known as "the mud angels" — came from all over Europe and America to help rescue Florence's treasures.

The prompt intervention of restorers and new methods of restoration in the following decades made it possible to salvage almost all of the damaged artworks.

One masterpiece, however, was considered beyond saving. Giorgio Vasari's "Last Supper," a large painting on five wooden panels, remained for four decades in storage, and restorers did not even dare to touch the cracked panels.

Today, Vasari's "Last Supper," the last major flood-damaged artwork that remained untreated, has been returned to public viewing in Santa Croce Church.

"It's a dream that has become reality," Marco Ciatti, head of the renowned restoration center Opificio delle Pietre Dure (OPD) in Florence, said.

More than 8 feet high and 21 feet across, Vasaris' painting was commissioned by the nuns of the Murate convent in Florence. Vasari was best known for writing one of the first great books of art history, "Lives of the Most Excellent Italian Painters, Sculptors." He was also a painter and architect.

The nuns' cloistered rule prohibited male artists from staying in the convent, so Vasari split the painting of Christ and his disciples into five portable poplar panels so he could work on the piece elsewhere and then transport it into the convent in parts. He completed the monumental painting in 1546.

After being moved several times, the "Last Supper" was installed at the museum of Santa Croce Church. When the river flooded, it remained completely immersed in filthy, oily water for at least 12 hours.

In the first hours after the flood, a team of restorers, led by art conservator Umberto Baldini, separated the panels and attached protective sheets of Japanese paper all over them in a desperate attempt to prevent the paint from flaking off.

"We can now say that system has worked. However, the glue used to attach the paper was a very strong acrylic resin which over the decades became an impermeable plate," Ciatti told Seeker.

One of the panels as it appeared 10 years ago.

When Ciatti showed me the panels 10 years ago, on the 40th anniversary of the flood, all I could see was a gray crust. Laying horizontally in the cavernous OPD lab, the panels were a sorry sight. Vasari's painting was totally unviewable under a crust of dried, cracked paper.

Ciatti's team had to face several issues. First, there was the problem of the wood support and the ground layer underneath the painting. Consisting of a binder, chalk and animal glue, this layer was the surface for the paint.

"As the wood panels dried, they shrank, stressing the painting's surface. Meanwhile the chalk and glue, which are soluble in water, degraded dramatically," Ciatti said.

"The contraction of the wood and the decohesion of the ground layer caused the painted surface to detach," he added.

Meanwhile, restorers faced another problem: how to peel the paper and the resin away without removing Vasari's paint.

Ten years ago, Roberto Bellucci, senior painting conservator at the Opificio, figured out how to remove the paper layer and the acrylic resin used as a glue. During my visit at the Opificio, I was lucky to see a bearded St. Peter emerging from the paper crust for the first time in 40 years.

Surprisingly, the blue and yellow of St. Peter's clothes were still vivid and looked much as they did before the flood.

"The color was still there, beneath the dirt, the glue and the paper. Without Baldini's emergency intervention, the painting would have been lost forever," Ciatti said.

Restoration of Giorgio Vasari's Last Supper

When the Getty Foundation and Prada provided a major grant to the OPD, Ciatti's team was able to restore the wood panels and stabilize the artwork in four year's time.

Senior painting conservator Ciro Castelli returned the wood to its original size by taking advantage of the splits that had opened in the waterlogged panels. Tiny slivers of poplar wood were inserted in the gaps to counter the contraction of the wood.

Using special synthetic resins, Bellucci managed to restore adhesion of the flaked paint to the surface, while securing the ground layer.

"The result is amazing. It went beyond my expectations. Our success is due to innovative products and technologies, but most of all to the dexterity of our restorers," Ciatti said.

The "Last Supper" now appears in all its glory of vibrant color, light and shadow.

Ciatti explained that any minor loss of color in the painting was not caused by the flood but likely by previous restoration efforts. He found inscriptions describing at least two interventions on the painting in 1594 and 1718.

Read more at Discovery News

Bionic Eye Creates a Bright Spot for the Blind

Finally, the lights are coming on.

Over the past several years, people with a degenerative eye disease could recover some vision through a high-tech prosthetic system. Patients went from complete darkness to seeing crude outlines of objects and people. Now Second Sight, the company behind that bionic eye, is developing neurotechnology that promises to do the same for millions worldwide who are blind from other causes.

Recently the company announced they had completed a successful proof of concept study at UCLA. A team there sent wireless signals to the brain of a blind patient through a simple device, which produced spots of light for her.

"It told us that yes, you can stimulate the visual cortex, you can produce a spot of light, and the patient can see that spot and localize it," Second Sight president and CEO Will McGuire told Seeker. Those results are informing the creation of a new product for artificial vision called Orion I that the company hopes to begin testing next year.

Orion I differs from Second Sight's current Argus II system, which has FDA approval to treat patients in the advanced stages of a degenerative disease that destroys the retina known as retinitis pigmentosa. Eventually the person can't tell whether the sun is out or an overhead light is turned on, McGuire explained.

Argus II has three main components: eyewear containing a video camera that captures and transmits footage, a small wearable video processing unit and a tiny electronics package that must be surgically implanted in the eye by a specialist. The glasses transmit imaging data in real time to 60 electrodes that are attached to the retina. These electrodes light up in patterns that replicate what the camera sees.

Second Sight

"What the patients will see is not vision like you or I. It's going to be their bionic vision," McGuire said. "Maybe they'll see the outline or movement of their cat or dog, the floor, the window, a doorway. They might see the handle for the refrigerator." He added that a cane or seeing eye dog would still be needed to help with outdoor navigation.

Second Sight, which has offices in California and Switzerland, has treated around 200 patients with the Argus II. McGuire said that just under 400,000 people worldwide have legal blindness from retinitis pigmentosa.

However, an estimated six million people globally are blindness for other reasons including cancer, trauma, glaucoma and diabetes. In those cases, the eye or optical nerve is completely nonfunctioning. Stimulating the retina won't help. Instead, the Second Sight team wants to bypass the retina and go straight to the surface of the brain responsible for vision.

Read more at Discovery News

Pillars of cosmic destruction: Colorful Carina Nebula blasted by brilliant nearby stars

These composite image shows several pillars within the Carina Nebula which were observed and studied with the MUSE instrument, mounted on ESO's Very Large Telescope. The massive stars within the star formation region slowly destroy the pillars of dust and gas from which they are born.

Spectacular new observations of vast pillar-like structures within the Carina Nebula have been made using the MUSE instrument on ESO's Very Large Telescope. The different pillars analysed by an international team seem to be pillars of destruction -- in contrast to the name of the iconic Pillars of Creation in the Eagle Nebula, which are of similar nature.The spires and pillars in the new images of the Carina Nebula are vast clouds of dust and gas within a hub of star formation about 7500 light-years away. The pillars in the nebula were observed by a team led by Anna McLeod, a PhD student at ESO, using the MUSE instrument on ESO's Very Large Telescope.

The great power of MUSE is that it creates thousands of images of the nebula at the same time, each at a different wavelength of light. This allows astronomers to map out the chemical and physical properties of the material at different points in the nebula.

Images of similar structures, the famous Pillars of Creation* in the Eagle Nebula and formations in NGC 3603, were combined with the ones displayed here. In total ten pillars have been observed, and in so doing a clear link was observed between the radiation emitted by nearby massive stars and the features of the pillars themselves.

In an ironic twist, one of the first consequences of the formation of a massive star is that it starts to destroy the cloud from which it was born. The idea that massive stars will have a considerable effect on their surroundings is not new: such stars are known to blast out vast quantities of powerful, ionising radiation -- emission with enough energy to strip atoms of their orbiting electrons. However, it is very difficult to obtain observational evidence of the interplay between such stars and their surroundings.

The team analysed the effect of this energetic radiation on the pillars: a process known as photoevaporation, when gas is ionised and then disperses away. By observing the results of photoevaporation -- which included the loss of mass from the pillars -- they were able to deduce the culprits. There was a clear correlation between the amount of ionising radiation being emitted by nearby stars, and the dissipation of the pillars.

Read more at Science Daily

Frog, toad larvae become vegetarian when it is hot

Amphibians are a group that is highly sensitive to global warming due to the permeability of their skin and their complex lifecycle, which combines an aquatic stage as larvae and a terrestrial stage when young and as adults.

Climate change is currently one of the greatest threats to biodiversity, and one of the groups of animals most affected by the increase in temperature is amphibians. A team of scientists with Spanish participants studied how heat waves affect the dietary choices of three species of amphibian found on the Iberian Peninsula: the European tree frog, the Mediterranean tree frog and the Iberian painted frog.

Global warming is causing not only a general increase in temperatures, but also an increase in the frequency and intensity of extreme weather events, such as flooding, heat waves and droughts. These environmental changes pose a challenge for many organisms, among them amphibians, who have to change their behaviour, physiology and life strategies in order to survive.

Researchers at the Universities of Lisbon (Portugal) and Uppsala (Sweden) studied the behaviour of three kinds of amphibians that inhabit the Iberian Peninsula: the European tree frog (Hyla arborea), the Mediterranean tree frog (Hyla meridionalis) and the Iberian painted frog (Discoglosus galganoi) to find out what effect heat waves can have on their diets.

As Germán Orizaola, co-author of the study published in the journal Ecology and a researcher at the Swedish university states "Among the many challenges climate change poses to natural ecosystems, the effect it can have on the dietary preferences of living organisms is a field of study that has been attracting researchers' attention in recent years."

Amphibians are a group that is highly sensitive to global warming due to the permeability of their skin and their complex lifecycle, which combines an aquatic stage as larvae and a terrestrial stage when young and as adults. "In fact, they are already experiencing sharp declines in population and extinction on a global scale, and they have become the focus of several research and conservation programmes in recent decades," the scientist explains.

A vegetable-based, animal-based or mixed diet

The researchers conducted a laboratory experiment in which they exposed the larvae of these three species to various kinds of heat waves, which varied in duration and intensity, by increasing the temperature of the water where they were growing.

"The larvae were kept in three different sets of conditions: with a solely vegetable-based diet, solely animal-based or a mixed diet. This third situation allowed us to assess whether they modified their diets towards a greater or lower percentage of vegetable matter," Orizaola adds.

They also examined the relationship between various carbon and nitrogen isotopes in the tissue of larvae with a mixed diet and compared them with those of exclusively vegetable-based or animal-based 'menus'. This enabled them to reconstruct the type of diet larvae exposed to a combined diet selected..

"Our results indicated first that larvae of various species have a diet adapted to the conditions under which they reproduce. The painted frog, which reproduces when it is cold, has a carnivorous diet, while the Mediterranean tree frog, which reproduces during the hottest season of the year, maintains a vegetarian diet," the investigator notes.

The most important result is that these larvae have very flexible dietary habits. All three species increased the percentage of vegetables consumed during heat waves. By analysing these larvae's rates of survival, growth and development, reduced effectiveness of the carnivorous diet in favour of a vegetarian diet was discovered in hot conditions.

Read more at Science Daily

Hurricanes from three million years ago give us clues about present storms

The team studied storm development from the Pliocene era, roughly three million years ago, and chose that time period because it was the last time the Earth had as much carbon dioxide as it does now, and the changes in climate from it can play a major role in storm formation and intensity.

Studying hurricane and tropical storm development from three million years ago might give today's forecasters a good blueprint for 21st century storms, says a team of international researchers that includes a Texas A&M University atmospheric sciences professor.

Robert Korty, associate professor in the Department of Atmospheric Sciences at Texas A&M, along with colleagues from China, Norway, and the University of Wisconsin, have had their work published in the current issue of PNAS (Proceedings of the National Academy of Sciences).

The team studied storm development from the Pliocene era, roughly three million years ago, and chose that time period because it was the last time Earth had as much carbon dioxide as it does now, and the changes in climate from it can play a major role in storm formation and intensity.

Using computer models and simulations, the team found an increase in the average intensity during the period and the storms most often moved into higher latitudes -- to a more northward direction.

"There seems to be a limit on how strong these ancient storms might be, but the number getting close to the limit appears to be larger during warmer periods," Korty explains.

"They reached their peak intensity at higher latitudes, following an expansion of tropical conditions with warming. It is consistent with smaller changes in the same patterns that we have observed over recent decades and project to continue over the next 100 years. I think it gives us greater confidence in some trends we are witnessing about how storms may change in future years."

Researchers today know that the oceans continued to be relatively warm during the Pliocene era, though there has been some uncertainty where waters were warmest. Their study found that the increase in average intensity and in the poleward expansion occurred regardless of where the greatest change in temperatures occurred in the Pliocene.

Read more at Science Daily