Jul 11, 2015
Transits of Venus are so rare that they only happen twice in a lifetime. About every 115 years, Venus will appear to cross over the face of our home star twice, with eight years passing between the pair of transits. This stunning phenomenon is not only incredible to watch, but it provides a unique opportunity for scientific observations of one of our nearest neighboring planets.
NASA'S Solar Dynamics Observatory, or SDO, and the joint Japanese Aerospace Exploration Agency and NASA's Hinode mission took pictures of the entire event in several wavelengths of light. A team of scientists led by Fabio Reale of the University of Palermo used these pictures to watch the backlit planet as it crossed in front of the sun. By observing the planet's atmosphere in different wavelengths of light during its journey, they learned more about what kinds of atoms and molecules are actually in its atmosphere. This work was published in Nature Communications on June 23, 2015.
Just as on Earth, each of the layers of Venus' atmosphere absorb light differently from one another. Some layers may completely absorb a certain wavelength of light, while that same wavelength can pass right through another layer. As Venus passes across the face of the sun -- which emits light in almost every wavelength of the electromagnetic spectrum -- scientists get a rare chance to see how all different types of light filter through Venus's atmosphere.
A layer in the upper atmosphere around Venus--called the thermosphere--absorbs certain high-energy wavelengths of light. When looking at the planet against the sun in one of these high-energy wavelengths, the thermosphere will appear opaque, rather than transparent as it does in visible light.
"Radiation goes into the atmosphere and is absorbed, creating ions and a layer of the atmosphere called the ionosphere," said Dean Pesnell, SDO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Because the energy in this light is captured by the ions, it is not re-emitted on the other side. In certain wavelengths, Venus's atmosphere is as solid as a wall, blocking light from traveling to our eyes. To our telescopes, the atmosphere is as dark as the planet itself -- so, Venus will appear to have a different size, depending on the wavelength of the telescope's pictures.
Reale and his team chose images of the Venus transit taken in several X-ray and ultraviolet wavelengths and measured the apparent size of the planet to within several miles. For each set of pictures, the team calculated just how large the atmospheric blocking was--a measure of how high in Venus' atmosphere that particular wavelength of light is completely absorbed.
Because the various types of atoms absorb light slightly differently, the height of this light absorption lets scientists know how many and what types of molecules make up Venus's atmosphere. This information is important for planning missions to Venus, as those ions and molecules can change the amount of course-altering drag a spacecraft feels.
"Learning more about the composition of the atmosphere is very important for understanding the braking process for spacecraft when they enter the upper atmosphere of the planet, a process called aerobraking," said Reale.
The shape of Venus' atmosphere also gave scientists important clues to how the sun impacts the atmosphere. "If the atmosphere observed were asymmetric, that could tell us more about how the star is impacting the planet," said Sabrina Savage, NASA project scientist for Hinode.
During the transit, only the sides of the atmosphere could be seen, but they were particularly interesting areas. From the perspective of Venus, these were the areas where day turns into night and night turns into day--on Earth, these transition areas can host interesting effects in the ionosphere. The data from the Venus transit showed that these two transition areas are virtually the same.
"The planet appeared very round in all wavelengths," said Pesnell. "If the transition from day to night were different from the transition from night to day, you would expect a bulge in the atmosphere on one side of the planet."
Studying the Venus transit can also help improve studies of planets around other stars. Such exoplanets are often discovered by transits just like this, as we can detect the very small amount of light the planets block as they pass across their home star. The more we can observe transiting planets close to home the more it will teach us about how to study distant exoplanets that we can't currently see in as much detail. When instrument technology advances, we may be able to gather better information about the atmospheres of such exoplanets as well.
Read more at Science Daily
Focussing light to improve sensing
The researchers used graphene to improve on a well-known molecule-detection method: infrared absorption spectroscopy. In the standard method, light is used to excite the molecules, which vibrate differently depending on their nature. It can be compared to a guitar string, which makes different sounds depending on its length. By virtue of this vibration, the molecules reveal their presence and even their identity. This "signature" can be "read" in the reflected light.
This method is not effective, however, in detecting nanometrically-sized molecules. The wavelength of the infrared photon directed at a molecule is around 6 microns (6,000 nanometres -- 0.006 millimeters), while the target measures only a few nanometres (about 0.000001 mm). It is very challenging to detect the vibration of such a small molecule in reflected light.
There is where graphene comes in. If given the correct geometry, the graphene is able to focus the light on a precise spot on its surface and "hear" the vibration of a nanometric molecule that is attached to it. "We first pattern nanostructures on the graphene surface by bombarding it with electron beams and etching it with oxygen ions," said Daniel Rodrigo, co-author of the publication. "When the light arrives, the electrons in graphene nanostructures begin to oscillate. This phenomenon, known as 'localized surface plasmon resonance,' serves to concentrate light into tiny spots, which are comparable with the dimensions of the target molecules. It is then possible to detect nanometric structures."
Reconfiguring graphene in real time to see the molecule's structure
There is more to it. In addition to identifying the presence of nanometric molecules, this process can also reveal the nature of the bonds connecting the atoms that the molecule is composed of.
When a molecule vibrates, it does not give off only one type of "sound." It produces a whole range of vibrations, which are generated by the bonds connecting the different atoms. Returning to the example of the guitar: each string vibrates differently and together they form one musical instrument. These nuances provide information on the nature of each bond and on the health of the entire molecule. "These vibrations act as a fingerprint that allow us to identify the molecule; such as proteins, and can even tell their health status" said Odeta Limaj, another co-author of the publication.
In order to pick up the sound given off by each of the strings, it has to be possible to identify a whole range of frequencies. And that is something graphene can do. The researchers "tuned" the graphene to different frequencies by applying voltage, which is not possible with current sensors. Making graphene's electrons oscillate in different ways makes it possible to "read" all the vibrations of the molecule on its surface. "We tested this method on proteins that we attached to the graphene. It gave us a full picture of the molecule," said Hatice Altug.
Read more at Science Daily
Jul 10, 2015
This finding may call most current models of galaxy formation into question, scientists added.
Astronomers investigated a supermassive black hole known as CID-947 using the W.M. Keck Observatory in Hawaii, NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton spacecraft.
This black hole, one of the largest ever seen, formed in the early universe about 11.7 billion years ago — 2 billion years after the Big Bang. The very fast motion of gas near the black hole suggests that it has a very high mass — the equivalent of about 7 billion suns.
The discovery was unexpected. "Our survey was designed to observe the average objects, not the exotic ones," study co-author C. Megan Urry, of Yale University, said in a statement. "This project specifically targeted moderate black holes that inhabit typical galaxies today. It was quite a shock to see such a ginormous black hole."
However, it was the mass of the galaxy surrounding this black hole that most surprised the research team.
"The measurements correspond to the mass of a typical galaxy," study lead author Benny Trakhtenbrot, an astrophysicist at the Swiss Federal Institute of Technology in Zurich, said in a statement. "We therefore have a gigantic black hole within a normal-size galaxy."
Most galaxies, including the Milky Way, possess at their hearts a supermassive black hole with a mass ranging from millions to billions of times the mass of the sun. The supermassive black holes seen up to now usually make up only 0.2 to 0.5 percent of the mass of their galaxies — far less than CID-947 does.
"The black hole has roughly one-tenth of the mass of the host," Trakhtenbrot told Space.com. "The black hole is massive compared with the normal host galaxy." The result was so surprising that the astronomers had outside experts verify their results independently.
Current models of galaxy formation suggest that galaxies and their supermassive black holes evolve in sync, growing at the same rate. However, CID-947 defies this rule, precociously growing much faster than researchers would have predicted.
"The black hole and the galaxy were not growing in parallel, as many models would suggest," Trakhtenbrot said.
In addition, the scientists found that, although the black hole had reached the end of its growth, stars were still forming in its galaxy. Prior research suggested that radiation and flowing gas from around the black hole would stifle the birth of stars.
Read more at Discovery News
Hints of what New Horizons will find have been trickling in as the piano-sized probe nears Pluto’s domain some 3 billion miles away.
Dark areas spotted on Pluto’s surface may be places where hydrocarbons like methane ice have been transformed over the eons by solar ultraviolet radiation. Another theory is that the dark spots are pockets where Pluto’s surface ice abates, exposing bare rock.
“We don’t know what we’ll find,” said New Horizons principal scientist Alan Stern, with the Southwest Research Institute in Boulder, Colo. “Virtually everyplace we’ve sent a spacecraft on a first reconnaissance mission like this we find out that our notions were flat-wrong.”
Like the groundbreaking Pioneer, Mariner and Voyager scouts of the 1960s, 70s and 80s, New Horizons has broad science goals, topped by three key questions: What do Pluto and its co-orbiting mate Charon look like? What are they made of? What’s Pluto’s atmosphere like?
The answers should flesh out understanding about how the solar system formed. For example, Pluto and thousands of sibling mini-planets in the Kuiper Belt region of the solar system may have assembled much closer to the sun, but were shot out beyond Neptune as Jupiter and the gas giants drifted into their present orbits.
New Horizons may find ice volcanoes on Pluto, similar to what NASA’s Cassini spacecraft found on Saturn’s moon Enceladus, an indication of possible subsurface water.
That may seem a contradiction for a world with surface temperatures almost 400 degrees below zero Fahrenheit. But Pluto, which is believed to be about 70 percent rock, could be internally heated by the natural decay of radioactive materials.
Once an oddball of the planetary family, Pluto turns out to be king of its own domain, accompanied in its 248-year orbit around the sun by at least five gravitationally tethered companions: Charon — a moon half its diameter — and four known small satellites, Nix, Hydra, Kerberos and Styx. New Horizons will target them all as it punches through the Pluto system for about 30 minutes on Tuesday.
Read more at Discovery News
The researchers followed five captive and three wild giant pandas (Ailuropoda melanoleuca) for about a year. By using GPS trackers and analyzing chemicals excreted in the pandas’ poop, they were able to measure the amount of energy the pandas spent each day. Surprisingly, the pandas expended only about 38 percent of the energy that an animal with the same body mass would require.
“We thought the metabolism of the panda would be low because the bamboo diet contains low energy,” said senior author Fuwen Wei, a professor of zoology at the Chinese Academy of Sciences in Beijing. “But it is very surprising that it is this exceptionally low, equal to the three-toed sloth, and much lower than the koala.”
The only known mammals that have a lower daily energy usage than the giant panda are the Australian rock rat (Zyzomys argurus), which spends 21 percent of its expected energy per day, and the golden mole (Eremitalpa namibensis), which spends 26 percent of its expected energy per day, the researchers wrote in the study.
However, while it’s unknown how the rock rat and golden mole conserve energy, the researchers found several ways that pandas save calories.
For starters, the GPS recordings showed that pandas are a lazy bunch; they don’t move a lot, and when they do, they move slowly. Captive pandas spent just a third of their time, and wild pandas about half of their time, moving around, the researchers found. Furthermore, wild pandas forage at an average speed of 50 feet (15.5 meters) an hour, a rate that is “very low,” the researchers wrote in the study.
The researchers also reviewed giant panda autopsy data, and found that relative to their size, the animals have a smaller brain, liver and kidneys than other bears. These small organs likely require less energy to function, saving the pandas precious calories, the researchers said.
Finally, the research team looked at the giant panda’s thyroid hormones, which regulate metabolism. A hormone sample taken from the captive pandas showed that levels of two thyroid hormones — thyroxine and triiodothyronine — were about half of what is seen in mammals with the same body mass, the researchers found.
In fact, these hormone levels were even lower than those seen in hibernating black bears (Ursus americanus), they said. Interestingly, giant pandas have thyroid hormone levels comparable to the gray seal (Halichoerus grypus), which lowers its metabolism while diving to conserve energy, the researchers said.
Read more at Discovery News
|This is how a male bee hummingbird looks at you when you ask it, "Why the long face?"|
Among these island wonders is the smallest bird in the world: the bee hummingbird. It weighs a mere 1/15 of an ounce—less than a dime—and builds nests the size of a quarter (sorry, all this talk of capitalism is getting to me). It hunts mosquitoes like a hawk would hunt a pigeon. And its eggs? They’re the size of coffee beans. The bee hummingbird is so tiny, it actually competes with insects for resources, as opposed to other birds. Oh, and it’s somewhat hyperactive, beating its wings up to 200 times per second.
Hummingbirds in general aren’t exactly known for their towering stature, but the shrinkage of the bee hummingbird is stunning. So why has this species gotten so much smaller than its peers? “You have in all communities on the Caribbean islands always two or three hummingbirds,” says ecologist Bo Dalsgaard of the University of Copenhagen. “If you go to the lowlands, there will be two hummingbirds, and if you go to the highlands there will be two hummingbirds. Always you find one large and one small hummingbird.”
|Here’s a mosquito for scale. No, not that—that’s a bee hummingbird. The other thing.|
So it shrank and shrank and shrank over evolutionary time to avoid running out of grub, targeting smaller flowers that the emerald hummingbird wouldn’t waste energy visiting. Even better, it’s never had much competition from insects, since pollinating bugs have a tough time traveling over water to colonize new island environments. The insect biodiversity just ain’t like it is on the mainland.
Yet the bee hummingbird is not alone in its teeniness. In fact, insular dwarfism, as it’s known, is pretty common. Over on Barbados, for instance, there’s an adorable snake that’s so small it can curl up on a quarter (sorry again), and its evolutionary story is much the same as the hummingbird’s. When the so-called threadsnake arrived on Barbados, it likely found an open niche that would typically go to something like a centipede. And perhaps the snake’s typical prey on the mainland never made it to the island. So like the bee hummingbird shrank down to exploit smaller flowers, the snake shrank down to exploit the larvae and eggs of social insects like ants and termites.
Dwarfism happens time and time again on islands, but being so tiny comes at a price, especially for a hummingbird, which already has quite the appetite to fuel its child-on-Red-Bull lifestyle. “It costs a lot of energy to be a small organism, because the metabolic rate and heat loss is relatively larger,” says Dalsgaard. “Hummingbirds must therefore feed very frequently, or go into torpor, a form of deep sleep, to save energy.”
|Bee hummingbird moms only raise two chicks, feeding them nectar, mosquitoes, and the occasional hint that it’s time to get off her back and go get a job already.|
So like a functioning narcoleptic, the bee hummingbird is probably slipping into torpor whenever it gets the chance. “For instance, at night when they cannot feed, they would need to consume substantial amounts of energy to keep their body temperature,” says ecologist Ana Martín González at the University of California, Berkeley. There are even “records of hummingbirds in torpor during heavy rains, when they cannot feed (they do feed during light rain) and they are not likely to get preyed upon.”
On top of all that, the bee hummingbird has to worry about finding someone for sexy time at some point. When the mating season rolls around, the males’ plumage transforms from a beautiful bluish-green into an even more beautiful sort of red-pink helmet … veil … thing, shown at the top of this story. They form groups known as leks and sing their hearts out, with the females sometimes choosing several males to mate with.
When she lays two coffee-bean-sized eggs in her nest, she doesn’t want the father(s) anywhere near them, for the males’ shiny new outfits are wildly obvious to predators. And she herself is quite cautious around the eggs. “She doesn’t fly straight into the nest,” says González. “She perches close to it, then waits there for some time, until nothing is around and then goes to the nest.” The eggs hatch after about three weeks, and she feeds the chicks for three more weeks on nectar, supplemented with mosquitoes. And then they’re off into the world.
Read more at Wired Science
Jul 9, 2015
Used to construct monuments such as the Pantheon and the Coliseum, Roman concrete has withstood two millennia of attacks by time and the elements, including wave and water, since it was also used to create artificial harbors throughout the Mediterranean.
Tiziana Vanorio, professor at the Geophysicist Department, Stanford’s School of Earth, Energy & Environmental Sciences, discovered that a natural process reflecting that of the engineering of the Roman concrete occurs in the subsurface of Campi Flegrei (Phlegraean Fields),a large volcanic area west of Naples.
The rock’s microstructures in these sunken volcanic fields have shown an exceptional strength, able to withstand tremendous strains.
Campi Flegrei lies at the center of a large depression, or caldera, and comprises fissures and craters formed during past eruptions, the last of which occurred in 1538.
The city of Pozzuoli is nestled within the caldera and was founded in 600 B.C. by the Greeks. Known to Italians as the birthplace of movie star Sophia Loren, the city was in Roman times one of the major trading ports of the Mediterranean, called Puteoli.
Beginning in 1982, the ground beneath Pozzuoli began rising at an alarming rate. Within two years, the town was raised by six feet — an amount unprecedented anywhere in the world.
The ground swelling was accompanied by persistent seismic activity, and nearly 40,000 people were evacuated from Pozzuoli.
“Ground swelling occurs at other calderas such as Yellowstone or Long Valley in the United States, but never to this degree, and it usually requires far less uplift to trigger earthquakes at other places,” Vanorio said.
“At Campi Flegrei, the micro-earthquakes were delayed by months despite really large ground deformations,” she added.
To answer the long standing question of why the subsurface of the caldera was able to accommodate the deformation without immediately releasing the stored energy through rock fracturing or cracking, Vanorio and a post-doctoral associate, Waruntorn Kanitpanyacharoen, now at Chulalongkorn University in Thailand, analyzed the rock cores from wells that were drilled in the caldera just before the Pozzuoli uplift.
The results, detailed today in Science, showed impressive similarities with the Roman concrete engineering.
“The Roman concrete was made by mixing slaked lime and pozzolana, the volcanic ash from Campi Flegrei. Similar to this technique, the natural process in Campi Flegrei forms a layer, laying between 3200 and 6500 feet, that is made up of a fibrous substance resulting from the mixture of lime and pozzolana,” Vanorio told Discovery News.
The core samples showed that in the Campi Flegrei caldera, the natural lime comes from the decomposition of deep carbonate rocks due to the presence of high temperature and mineral fluids, a process called decarbonation.
“Once formed, the lime is transported by the geothermal fluids up to shallower depths where it finds the rock layer made of pozzolana ash and reacts with it,” Vanorio said.
“It is this reaction that leads to the formation of fiber minerals, Tobermorite and Ettringite, that are also found in man-made concrete, including Roman concrete,” she added.
Vanorio suspects the ancient Roman builders made their remarkable technological breakthrough after observing interactions between the volcanic ash at Pozzuoli and mineral water seeped through the underground rocks in the region.
The speculation is supported by historical sources. The Roman philosopher Seneca (4 B.C. – 65 A.D.) and before him the 1st century B.C. author, architect and civil engineer Vitruvius, noted that there was something special about the ash at Pozzuoli.
"The dust at Puteoli becomes stone if it touches water," Seneca wrote.
Pulvis Puteolanus, Pozzuoli's highly reactive volcanic ash, was used across the ancient world. Until the submersion of the harbor in the fourth century AD, Puteoli was the major commercial and military port of the Roman Empire, and it was common for ships to use pozzolana as ballast while trading grain from the eastern Mediterranean.
As a result, the use of Roman concrete became widespread. Archeologists have recently found that piers in Alexandria in Egypt, Caesarea in Israel, and Cyprus are all made from pozzolana-based Roman concrete.
From a material science stand point, the existence of a natural process in the subsurface of the Campi Flegrei caldera that produces an impermeable, and fiber-reinforced concrete-like rock is extremely important, says Vanorio.
Rocks are generally more brittle than ductile -- they crack when stressed, thus generating earthquakes. On the contrary, the presence of an intricate network of intertwining fibers throughout the caprock of the Campi Flegrei's caldera clearly created a rock with exceptional properties and high strength.
Read more at Discovery News
“Hikikomori,” which translates to “withdrawn,” describes young people with a disorder characterized by extreme social isolation, in which sufferers lock themselves in their bedrooms and refuse to come out, even for years at a time. This disorder afflicts as many as one million Japanese citizens, overwhelmingly men in their 20s and 30s.
Hikikomori typically isolate themselves following a setback, such as failure in school or a bad breakup, that triggers a deep sense of shame. Hikikomori often exhibit symptoms of depression and obsessive-compulsive disorder during periods of withdrawal.
Takahiro Kato, a psychiatrist specializing in hikikomori, explains that the root cause of the condition is cultural, citing “a strong sense of embarrassment and an emotional dependence on the mother” in an interview with ABC News (Australia).
While a handful of isolated cases of hikikomori have been found in South Korea, Hong Kong, and even Italy, the condition is considered a Japanese phenomenon, a kind of culture-bound syndrome.
A culture-bound syndrome is an affective, behavioral or cognitive disorder unique to a specific culture or group. Various cultural and social factors can contribute to the development of this condition. In the case of hikikomori, one contributor in Japanese society is “sekentei,” a person’s reputation in the community and the pressure to impress others, as explained by BBC News.
This same pressure can lead to a more prolonged period of withdrawal, as the isolation itself compounds the sense of embarrassment, and may delay relatives from seeking treatment for hikikomori.
One similar culture-bound syndrome linked to Japan is “taijin kyofusho,” a condition in which people suffer from extreme social anxiety as a result of often imagined physical shortcomings.
The American Academy of Family Physicians in 2010 reported the case of a 24-year-old graduate student from Japan, who was convinced his body odor offended other students. Despite the fact that no student ever complained of any odor, and the researchers themselves were unable to detect any offensive scent, the student was so anxious about his smell that he barely left his room and fell into depression.
Not all culture-bound syndromes originate in Japan of course. The book, “The Culture-Bound Syndromes,” by Charles C. Hughes listed nearly 200 folk illnesses upon its publication in 1986. Some of the more unusual conditions identified as culture-bound syndromes include:
Amok: The expression “running amok” comes from the condition of the same name, first introduced to the West in the journals of Captain Cook. Cook described how affected individuals among Malay tribesmen would behave violently, going on homicidal rampages that involved an average of 10 victims. The killer has complete amnesia of the event once it’s over, assuming he or she doesn’t commit suicide or isn’t killed in the process, as is often the case. In addition to Malaysia, this behavior has also been observed in indigenous tribes in the Phillippines, Laos and Papua New Guinea.
Ataque de nervios: Similar to a nervous breakdown, this condition is a panic disorder reported among Latino and Caribbean populations. Symptoms include uncontrollable shouting, crying and aggression. This syndrome is most often caused by family-related stress.
Dhat syndrome: This condition is prevalent in the Indian subcontinent, but has been identified in China, the Americas, Europe and Russia and well. Individuals coping with dhat, described as “semen-loss anxiety,” often show symptoms of sexual dysfunction and loss of virility. Seminal fluid is considered the “elixir of life” in these cultures, so losing it is often linked to fear of irreversible physical damage or even death.
Ghost sickness: This condition is linked with Native American tribes in the American Southwest and Southern Plains and marked by an overwhelming preoccupation with the deceased. Symptoms of this syndrome include weakness, hallucinations, anxiety and feelings of terror.
Koro: This term describes a panic-like anxiety among men that their penises will withdraw into the abdomen and kill them. Symptoms include overwhelming concern about genitalia and fears of impotence or imminent death. This syndrome has been linked to men in China, although the koro phenomenon has manifested in a variety of cultures in Asia and Africa, so there is some debate as to whether koro is a universal condition.
Read more at Discovery News
Mission representatives say New Horizons is “back on track” after it experienced an anomaly on July 4 that caused it to go into a temporary “safe mode.” The anomaly was later shown to be the result of too many commands being executed at once.
The spacecraft is already collecting data about the Pluto system, and its nine-day flyby sequence will continue through July 16. It’s taken more than nine years for the $700 million New Horizons mission to traverse the 3 billion miles (4.8 billion kilometers) between Earth and Pluto, but the peak of the spacecraft’s journey will last a matter of hours.
As the probe nears Pluto, NASA TV will air daily updates from mission control at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, at 11:30 a.m. ET (1530 GMT), through July 14.
In an update Wednesday (July 8), Alice Bowman, mission operations manager for New Horizons, said the July 4 anomaly gave the mission team a bit of a scare.
“We were all a little bit afraid of what might happen, but we put on our engineering hats and we went down our checklist and we did what needed to be done to recover that spacecraft to operational mode,” Bowman said.
New Horizons returned to nominal science operations on Tuesday (July 7). Mission team members reported that about 30 observations were lost during those three days. Those data represent “less than 1 percent of the total science that the New Horizons team hoped to collect between July 4 and July 16,” NASA said in a statement.
“We’re delighted with the New Horizons response to the anomaly,” Jim Green, NASA’s director of planetary science, said in the statement. “Now we’re eager to get back to the science and prepare for the payoff that’s yet to come.”
Read more at Discovery News
The plant, Nepenthes hemsleyana, communicates via special structures that reflect the bats’ ultrasonic calls right back to the flying mammals, according to a study published in the latest issue of the journal Current Biology.
“With these structures, the plants are able to acoustically stand out from their environments so that bats can easily find them,” co-author Michael Schöner of Ernst-Moritz-Arndt-University of Greifswald in Germany said in a press release.
“Moreover,” he continued, “the bats are clearly able to distinguish their plant partner from other plants that are similar in shape, but lack the conspicuous reflector.”
Schöner, senior author Gerald Kerth, and their colleagues determined that the bats poop in and around the plants, keeping the latter well fertilized with their droppings.
Once the bats find the plants, they settle in towards the top — away from the plant’s deadly digestive liquids — and enjoy a cool place to roost. The seemingly clever plants get something out of the deal too.
It was that discovery that led to the study on the ultrasound communication in the first place, as the researchers wondered how the carnivorous plants were so successful at grabbing the attention of bats flying by.
Suspecting that echolocation was involved, the scientists used an artificial biomimetic bat head that emits and records ultrasounds to test the pitcher plant’s acoustic reflectivity from different positions and angles. The experiments uncovered a strong echo reflection from the plant’s back walls, where the shape works perfectly as an effective reflector.
Subsequent behavioral experiments showed that the bats respond to those sounds echoed back to them from the plants. Bats were better at finding partially hidden pitcher plants when their reflectors were intact than when the reflector had been reduced. The bats also chose pitcher plants more often as the best places to roost when the reflector had not been reduced.
The study answers a longstanding question about these particular plants: Why don’t they feast on many insects versus what other pitcher plants do? As it turns out, they don’t have to, given all of the nutrient-rich bat poop nearby. The study further adds to the growing body of research showing that plants can solve complex problems without having a brain.
Read more at Discovery News
Jul 8, 2015
"A planet's atmosphere provides a good guide to likely conditions on the surface," said Barstow, of the University of Oxford. "The Earth's atmosphere contains significant amounts of nitrogen, oxygen, ozone and water. By contrast, its inhospitable 'evil twin', Venus, has an atmosphere made mostly of carbon dioxide, which drives its surface temperature to a blistering 450 degrees Celsius."
A successor to the Hubble Space Telescope, JWST is due for launch in 2018 and will study the Universe in infrared wavelengths. Barstow's study shows that JWST may be able to differentiate between a planet with a clement, Earth-like atmosphere, and one with more hostile conditions such as are found on our neighbouring planet Venus. JWST will have the capability to detect key markers that could indicate the presence of a climate like our own when looking at Earth-sized planets around stars that are smaller and redder than our Sun.
Different gases have already been identified successfully in the atmospheres of several large, hot, Jupiter-sized planets by studying tiny variations in the starlight that passes through their atmospheres when they cross in front of their parent stars. However, these variations are miniscule: the light filtered through the exoplanet's atmosphere is one ten-thousandth of the total starlight detected. Studying planets the size of the Earth is an even greater challenge. Although JWST would struggle with analysing a Solar System exactly like our own, it would be capable of studying Earth-like planets around cooler stars -- if such a system were to be found.
"If we took the Earth and Venus, and placed them in orbit around a cool, red star that's not too far away, our study shows that JWST could tell them apart. Earth's ozone layer, 10 kilometres above the surface, is produced when light from the Sun interacts with molecules of oxygen in our atmosphere, and it produces an unmistakable signal that could be detected by JWST. Venus, without a substantial ozone layer, would look very different," said Barstow. "That's assuming that planets starting out like Earth and Venus would evolve in the same way around a cool star!"
Read more at Science Daily
As you can see from this photo taken by an astronaut aboard the International Space Station, the shallow, six-mile long, 15,000-acre lake is a rusty orange-red color, as the result of algae that thrive in its salty water.
Oddly, the lake is also filled with white islands, which actually are massive mounds of borax, a mineral used in paint, glass, and in a cleaning product famous for its sponsorship of the classic TV western “Death Valley Days.”
If that’s not a sufficiently strange color scheme, don’t worry. Occasionally the lake has green phases as well because different algae display different colors. The type of algae at any given time is determined by the relative salinity, which changes as warmer weather causes some of the lake to evaporate, and the temperature of the water itself, according to NASA Earth Observatory.
The algae in Laguna Colorada provide more than just pigment. They’re also a food source for flamingos. The lake is home to a particularly rare species, the Puna or James flamingo, (scientific name Phoenicoparrus jamesi).
The plain upon which Laguna Colorada is situated also is home to a number of other lagoons with exotic colors, due to mineral deposits in their waters. For example, there’s Laguna Verde, which is known for its startling emerald-green shade.
If you’re going to visit the lake, pack some warm pajamas. Temperatures in the area can drop to bitterly cold lows overnight, according to the “Rough Guide to Bolivia.”
From Discovery News
Usually, NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, would be looking at relativistic jets of material blasting from black hole behemoths millions to billions the mass of the sun, or the superheated hearts of supernovae, but in a follow-up to arguably one of the most beautiful space images ever created, astrophysicists have created a full-disk portrait of the high-energy X-ray-generating processes in the sun’s corona.
In this stunning image, NuSTAR X-ray observations (in blue) have been superimposed over ultraviolet observations made by NASA’s Solar Dynamics Observatory (SDO) and lower-energy X-rays imaged by the Japanese Hinode observatory to produce a wonderfully psychedelic solar view.
The solar corona — the sun’s multi-million degree “atmosphere” — is a hothouse of magnetically-dominated processes and the focus of one of the most enduring mysteries in stellar science. Put simply, the corona is too hot; the tenuous plasma that extends from the sun’s photosphere (colloquially known as the sun’s “surface”) can be millions of degrees Kelvin (Celsius) hotter than the sun’s uppermost layers. Classical thermodynamics shouldn’t allow this to happen — it doesn’t, for example, get hotter the further you move your hand away from an open flame.
But solar scientists are hot on the trail of finding out what mysterious coronal processes must be going on and these unique observations by NuSTAR may be able to help out.
One coronal heating mechanism focuses on small-scale flaring events called nanoflares. These flares may be small on solar scales, but they are thought to dump huge quantities of energy into the corona, heating it. Current observatories cannot see individual nanoflares as they are too small to be resolved, but they do generate X-ray emissions right in the observing threshold for NuSTAR, so the mission should be able to spot their high-energy X-rays.
As the sun is still fairly active in its 11-year solar cycle after reaching solar maximum in 2013, the mission has picked out some regions in the sun’s atmosphere rumbling with X-ray activity, with “hotspots” over active regions bustling with microflares and, possibly, nanoflares.
“We can see a few active regions on the sun in this view,” said Iain Hannah, of the University of Glasgow, in a press release. “Our sun is quietening down in its activity cycle, but still has a couple of years before it reaches a minimum.”
Hannah presented this observation on Wednesday at the National Astronomy Meeting in Llandudno, Wales.
To measure a definitive nanoflare signal, however, the sun needs to calm down to a more quiescent state, a phase that solar astronomers are anticipating over the next few years as it approaches solar minimum. A slowdown in magnetic activity will reduce the number of active regions and quench powerful flaring activity. In this quiescent state, the high-energy X-ray nanoflare emissions could be detected from the noise.
“We still need the sun to quieten down more over the next few years to have the ability to detect these events,” said Hannah.
Read more at Discovery News
“Wendiceratops helps us understand the early evolution of skull ornamentation in an iconic group of dinosaurs characterized by their horned faces,” explained co-author David Evans in a press release.
“The wide frill of Wendiceratops is ringed by numerous curled horns, the nose had a large, upright horn,” Evans said, “and it’s likely there were horns over the eyes too. The number of gnarly frill projections and horns makes it one of the most striking horned dinosaurs ever found.”
Evans, of the Royal Ontario Museum and the University of Toronto, along with Michael Ryan of the Cleveland Museum of Natural History, reported the find in the latest issue of the journal PLOS ONE. They named the dinosaur after renowned Alberta fossil hunter Wendy Sloboda, who discovered the site where the remains were found in 2010.
Over 200 bones representing at least four Wendy dinosaurs (three adults and one juvenile) were collected from the lower part of what’s known as the Oldman Formation in Alberta. The paleontologists say that Wendy dinos lived around 79 million years ago.
On its head, Wendy had a series of forward-curling, hook-like horns that adorned its wide, shield-like frill, which projected from the back of its skull. Although made out of horn, the ornamentation gave Wendy a curly hair look.
“Wendiceratops is inferred to have a large, upright nasal horn,” wrote the authors, “which represents the oldest occurrence of this feature in Ceratopsia.” This likely foreshadowed later evolution of this and other facial horns in such dinosaurs.
For example, just over 10 million years after Wendy lived, Triceratops emerged. This large, four-legged and plant-eating dinosaur famously had a massive head with two large horns, a smaller horn on its beaked snout, and a bony frill above the neck. By comparing these features with those of ancestor Wendy, the researchers gained clues on how and why the horns and frills evolved.
Read more at Discovery News
Jul 7, 2015
More practically, the wireless ultrasound devices complement standard radio transmission using electromagnetic waves in areas where radio is impractical, such as underwater, but with far more fidelity than current ultrasound or sonar devices. They can also be used to communicate through objects, such as steel, that electromagnetic waves can't penetrate.
"Sea mammals and bats use high-frequency sound for echolocation and communication, but humans just haven't fully exploited that before, in my opinion, because the technology has not been there," said UC Berkeley physicist Alex Zettl. "Until now, we have not had good wideband ultrasound transmitters or receivers. These new devices are a technology opportunity."
Speakers and microphones both use diaphragms, typically made of paper or plastic, that vibrate to produce or detect sound, respectively. The diaphragms in the new devices are graphene sheets a mere one atom thick that have the right combination of stiffness, strength and light weight to respond to frequencies ranging from subsonic (below 20 hertz) to ultrasonic (above 20 kilohertz). Humans can hear from 20 hertz up to 20,000 hertz, whereas bats hear only in the kilohertz range, from 9 to 200 kilohertz. The grapheme loudspeakers and microphones operate from well below 20 hertz to over 500 kilohertz.
Graphene consists of carbon atoms laid out in a hexagonal, chicken-wire arrangement, which creates a tough, lightweight sheet with unique electronic properties that have excited the physics world for the past 20 or more years.
"There's a lot of talk about using graphene in electronics and small nanoscale devices, but they're all a ways away," said Zettl, who is a senior scientist at Lawrence Berkeley National Laboratory and a member of the Kavli Energy NanoSciences Institute, operated jointly by UC Berkeley and Berkeley Lab. "The microphone and loudspeaker are some of the closest devices to commercial viability, because we've worked out how to make the graphene and mount it, and it's easy to scale up."
Zettl, UC Berkeley postdoctoral fellow Qin Zhou and colleagues describe their graphene microphone and ultrasonic radio in a paper appearing online this week in the Proceedings of the National Academy of Sciences.
Radios and rangefinders
Two years ago, Zhou built loudspeakers using a sheet of graphene for the diaphragm, and since then has been developing the electronic circuitry to build a microphone with a similar graphene diaphragm.
One big advantage of graphene is that the atom-thick sheet is so lightweight that it responds well to the different frequencies of an electronic pulse, unlike today's piezoelectric microphones and speakers. This comes in handy when using ultrasonic transmitters and receivers to transmit large amounts of information through many different frequency channels simultaneously, or to measure distance, as in sonar applications.
"Because our membrane is so light, it has an extremely wide frequency response and is able to generate sharp pulses and measure distance much more accurately than traditional methods," Zhou said.
Graphene membranes are also more efficient, converting over 99 percent of the energy driving the device into sound, whereas today's conventional loudspeakers and headphones convert only 8 percent into sound. Zettl anticipates that in the future, communications devices like cellphones will utilize not only electromagnetic waves -- radio -- but also acoustic or ultrasonic sound, which can be highly directional and long-range.
"Graphene is a magical material; it hits all the sweet spots for a communications device," he said.
When Zhou told his wife, Jinglin Zheng, about the ultrasound microphone, she suggested he try to capture the sound of bats chirping at frequencies too high for humans to hear. So they hauled the microphone to a park in Livermore and turned it on. When they slowed down the recording to one-tenth normal speed, converting the high frequencies to an audio range humans can hear, they were amazed at the quality and fidelity of the bat vocalizations.
"This is lightweight enough to mount on a bat and record what the bat can hear," Zhou said.
Bat expert Michael Yartsev, a newly hired UC Berkeley assistant professor of bioengineering and member of the Helen Wills Neuroscience Institute, said, "These new microphones will be incredibly valuable for studying auditory signals at high frequencies, such as the ones used by bats. The use of graphene allows the authors to obtain very flat frequency responses in a wide range of frequencies, including ultrasound, and will permit a detailed study of the auditory pulses that are used by bats."
Read more at Discovery News
All this happened as a measles outbreak that began in December 2014 at Disneyland unfolded; 147 people became infected with the disease before the outbreak ended in April. Many who fell ill were not immunized against measles, and spurred in part by public concern over the episode California governor Jerry Brown introduced (and last week signed) a law requiring all school-attending children to be vaccinated for public safety.
The law does not require childhood vaccinations for every child — only those enrolled in California public schools. Parents are not required to vaccinate children who go to private home schools or are home-schooled.
The move was widely praised by doctors but had many detractors. For example actor Jim Carrey took to social media to claim that Brown’s “fascist” law would “poison more children with mercury and aluminum.” During his rant Carrey used a photo of an autistic boy, without his family’s permission, suggesting that his condition had been caused by vaccines; Carrey later apologized. With passionate advocates on both sides of the issue the debate is far from over.
Why do some people doubt vaccine safety and efficacy? One reason is that their effectiveness cannot be proven on an individual basis. For example even people who are effectively vaccinated against a specific disease can still catch it (no vaccination is completely effective, and you might catch a different virus strain than the one you were inoculated against). This can lead people to doubt the usefulness of vaccines: if it’s possible to catch a disease with or without a vaccination, what’s the point?
But this position misses that fact that vaccinated people are far less likely to get the disease in the first place, and if they do happen to get it the symptoms will be less severe and more survivable.
A specific person’s experience with a specific vaccine (or any other medicine) is not a valid measure of the overall effectiveness. However the institutions best equipped to conduct the necessary large-scale studies (i.e., governments and big drug companies) are also those that the public often distrusts, leading to conspiracy theories.
Indeed one reason the anti-vaccination theme is so persistent is the strong conspiracy theory element to it. Conspiracy theories are of course notoriously difficult, if not impossible, to disprove. Many people distrust the medical establishment and “Big Pharma” almost as much as they distrust the government. The assumption is that the dangers and risks of vaccines are being intentionally hidden from the public by doctors and drug companies, in collusion with the government, for big profits.
Joseph Uscinski and Joseph Parent, in their book “American Conspiracy Theories,” note bluntly that “Conspiracy theories about vaccines are partially to blame for decreased rates of vaccination and an increased incidence of disease.”
Andrea Kitta, an Associate Professor at East Carolina University and author of “Vaccinations and Public Concern in History,” notes that “The content of vaccines, especially in the case of preservatives, is a widely debated issue. Ingredients such as thimerosal, formaldehyde, mercury, and others, are frequently linked [in anti-vaccination claims] to the causation of diseases… All of these ingredients, regardless of whether or not they have been linked to an actual disease, are to blame because they are considered not ‘natural’.”
Many of the claims about “natural” versus “unnatural” chemicals used in vaccines have been thoroughly debunked. A USA Today article notes, for example, that “Vaccines have never contained methyl mercury, the toxic metal that can cause brain damage” and that while it’s true that vaccines contain aluminum, “babies get far more aluminum from food, including breast milk, than from vaccines.”
Given the current controversy some may think that protests about vaccinations are a recent phenomenon, but in fact the concerns date back centuries. There was resistance to the first smallpox vaccine, created in the late 1700s. Parents and the public — unfamiliar with medicine and how vaccination works — were horrified and disgusted when they learned that the vaccine was created by taking pus from the wounds of infected cows. Nevertheless, that procedure, as unappetizing as it may be, was effective and saved countless lives.
A British Anti-Vaccination League was created in 1853, asserting that the smallpox vaccine was dangerous, ineffective, and an infringement on personal rights by the government. Over 160 years later that theme continues to resonate strongly with anti-vaccination activists. Medical folklorist Kitta told Discovery News that “People who choose not to vaccinate truly believe their rights are being violated and believe they are in danger of further violation… Some people will now reject vaccines solely on the basis that they feel their rights are being violated—not because they necessarily oppose or are even uncertain about vaccination.”
Read more at Discovery News
The mounds were built 2,000 years ago by the Hopewell, an ancient Indian culture of the east-central area of North America well known for known for their animal-inspired artworks. The features stood about 49 miles north of St Louis, Illinois, and were excavated in the 1980s.
At that time, the largest of the mounds, measuring 91 feet in diameter and 8 feet high, revealed 22 people buried in a ring around a tomb containing an infant.
Within that ring, archaeologists also found a small animal interred with a beaded collar around its neck.
Since the Hopewell are known to have buried their dogs, the animal was believed to be a puppy and labelled as such.
But according to Angela Perri, a zooarchaeologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, the animal “is actually an immature bobcat.”
Detailing their findings in the Midcontinental Journal of Archaeology, Perri and colleagues Terrance Martin, curator of anthropology at the Illinois State Museum, and Kenneth Farnsworth, a Hopewell expert at the Illinois State Archaeological Survey in Champaign, established the bobcat was likely between 4 and 7 months old.
The compete skeleton showed no cut marks or other signs of trauma, indicating the animal had not been sacrificed.
Moreover, excavation photos showed the bobcat was respectfully placed in its grave, its paws placed together.
Read more at Discovery News
The moisture in the atmosphere of Mars could be particularly conducive to life if the water condenses out to form short-term puddles in the early morning hours.
“The conditions on Mars, where the relative humidity is high and the available water vapor is approximately 100 precipitable microns, is the equivalent of the drier parts of the Atacama Desert in Chile,” John Rummel, of East Carolina University, told Space.com by email.
Rummel reported on the location of several “special regions” on Mars — places with high potential to support Martian organisms today — during a talk the Astrobiology Science Conference in Chicago last month.
Warm enough and wet enough?
According to a 2014 report by the Mars Exploration Program Analysis Group (MEPAG) that Rummel co-authored, a special region on Mars is defined as “a region within which terrestrial organisms are likely to replicate.” These areas include “any region which is interpreted to have high potential for the existence of extant Martian life forms.”
Liquid water is key for the existence of life here on Earth. But Mars has very little liquid water on its surface today (though evidence suggests it once flowed in the past).
The air, however, is a different story. According to Rummel, the humidity of Mars is tied to temperature fluctuations. At night, relative humidity levels can rise to 80 to 100 percent, with the air sometimes reaching atmospheric saturation. The daytime air is far drier, due to warmer temperatures.
On Earth, some forms of life are able to survive in parched regions by poaching water from the humid air. Among these, lichens dominate, surviving in arid climates without succumbing to the dry spells that frequently occur. Some lichens in super-dry areas have been found to photosynthesize at relative humidity levels as low as 70 percent. Other research has demonstrated that a form of Antarctic lichen can adapt to life under simulated Martian conditions.
But humidity can only go so far. Although the lichen were found to metabolize through photosynthesis, no terrestrial organism has yet been discovered that can reproduce by relying on humidity alone. So far, liquid water continues to be a requirement for cell reproduction.
Life in Martian puddles?
Does that mean game-over for any hopeful Martian lichen? Not quite, Rummel said. As temperatures on the Red Planet drop at night, he explained, water could condense into ice or snow in regions where the pressure and temperature are high enough. As temperatures rise in the early morning hours, the ice or snow could melt and eventually evaporate, a process Rummel said could take minutes to hours.
In the 1970s, NASA’s Viking 2 lander observed nighttime condensation on Mars for nearly 200 days in a row, with water-frost dusting the landscape.
Read more at Discovery News
Jul 6, 2015
Headlining these efforts was supposed to be the HoloLens, a headset made by Microsoft that in part would allow ground controllers to look over the shoulders of astronauts. However, the Falcon 9 rocket carrying up a Dragon spacecraft exploded June 29; the cause is still being investigated. While there’s no date yet on when astronauts will use it in space, it will be used underwater very shortly.
Every year or so, NASA runs simulated space missions underwater called NEEMO (NASA Extreme Environment Mission Operations). In the two missions that occurred in 2014, astronauts tested out Google Glass to see if that was an easier way to implement procedures. The thinking was that by letting controllers “see” what the astronauts were doing, it would speed up the work.
In a technical report after the mission, however, the Google Glass was not found to be ideal. It was limited by battery life and had some issues with scrolling, among other things. After this happened and for unrelated reasons, the Glass project was shelved by Google. NASA’s next move is to see how Microsoft’s HoloLens will do.
On July 21, NASA will test HoloLens and its software counterpart (Sidekick) on the NEEMO 20 mission. Instead of the traditional written procedures and uploaded videos, the controller will be able to give guidance and even “draw annotations” in front of the crew member’s eyes, according to a NASA press release.
Time delays, however, would be a problem for astronauts working on Mars. How to have the procedures drop at at time when is convenient for the crew member, as opposed to running on the communications loop on top of what other people are saying? While that’s a bit far off for humans, Microsoft is working on a modified version of its virtual reality set for the Curiosity mission.
Read more at Discovery News
A group of Japanese scientists say they have a shooting-star secret formula — an undisclosed chemical mixture packed into tiny, inch-wide balls that the team hopes to eject from a satellite to create on-demand meteor showers, AFP reports.
A Japanese start-up company called ALE is partnering with researchers at multiple universities to create the artificial meteor showers, which will cost around $8,100 per meteor for buyers. The researchers said the manufactured meteors would be bright enough to be visible even in areas with light pollution, like Tokyo, assuming clear weather.
Natural meteor showers occur when dust and debris from space are heated by friction as they pass through Earth’s atmosphere. Meteors often burn up completely before reaching the ground. (If they do strike the Earth, they become known as meteorites.) The artificial meteoroids, which would be launched from a microsatellite 20 inches (50 centimeters) across, would burn up on entry as well, after racing in at 5 miles (about 8 kilometers) per second, according to the piece by AFP reporter Miwa Suzuki.
The cubelike satellite that would release the artificial shooting stars is being developed by ALE in conjunction with the outside researchers. The satellite would orbit the Earth from north to south at an altitude of about 250 to 310 miles (400 to 500 km) for months at a time before falling back to Earth and burning up.
ALE is keeping the chemical makeup of the pellets it would launch secret, but the company revealed that it is considering different chemical compositions to create streaks of different colors.
“Making the sky a screen is this project’s biggest attraction as entertainment,” Lena Okajima, the company’s founder and CEO, told AFP. “It’s a space display.” In case of bad weather, the shooting stars could be called off up to 100 minutes before the planned spectacle.
And while the artificial meteor showers would be beautiful, they could also be valuable to scientists. An aerospace engineer at Tokyo Metropolitan University, Hironori Sahara, told AFP that analyzing the light from a meteor can tell scientists about the temperature, density and movement of the atmosphere at that elevation. Natural meteor showers are unpredictable, but scientists would know exactly where to look to study ALE’s meteors.
Read more at Discovery News
The probe has been barreling toward an unexplored and recently discovered outer section of the solar system for more than nine years, aiming for a close pass by the Kuiper Belt planet Pluto on July 14.
Ground control teams over the weekend were beginning to upload the final batch of instructions for the flyby when New Horizons’ primary computer shut down on Saturday afternoon. During its automated switch to its backup computer, New Horizons dropped radio communications with Earth for a tense 81 minutes.
The glitch suspended science operations, which have been ongoing since January.
NASA expects it will take until Tuesday for New Horizons to return to full service.
The cause of the glitch was “a hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close flyby,” NASA wrote in a status report.
With New Horizons nearly 3 billion miles from Earth, round-trip radio communications take about nine hours, complicating engineers’ attempts to find and fix the problem.
No impact to New Horizons’ flyby of Pluto are expected and science observations lost during the shutdown and recovery do not affect any primary objectives of the mission, NASA added.
“We’re on the verge of returning to normal operations,” Jim Green, NASA’s director of planetary science, said in the statement.
From Discovery News
Many of the frozen dust ball’s features, which include a black crust over lakes of ice, flat-bottomed craters and mega-boulders scattered on the surface, were “consistent” with the presence of microbes, they said.
Observations by the European Space Agency’s Rosetta comet orbiter has shown that 67P/Churyumov-Gerasimenko “is not to be seen as a deep-frozen inactive body, but supports geological processes,” Max Wallis of the University of Cardiff said in a statement issued by the Royal Astronomical Society (RAS).
In fact, the comet racing towards the sun at a speed of 32.9 kilometers (20.4 miles) per second, “could be more hospitable to micro-life than our Arctic and Antarctic regions.”
Wallis and his colleague Chandra Wickramasinghe of the Buckingham Center for Astrobiology, presented their theory Monday to a meeting of the RAS in Llandudno, Wales.
They pointed to Rosetta’s detection of complex organic material, which gave the comet its surprisingly super-dark and low-reflecting surface, as “evidence for life.”
Furthermore, Wickramasinghe said that 67P’s gas ejections started “at distances from the Sun too far away to trigger surface sublimation”.
This implied that micro-organisms under the comet’s surface had been “building pockets of high pressure gases that crack overlying ice and vent organic particles,” he said by email.
Wickramasinghe also cited a rugged surface with evidence of re-sealed cracks and displaced boulders, and a covering of organics which “need to be resupplied.”
The observed features “are all consistent with a mixture of ice and organic material that consolidate under the Sun’s warming during the comet’s orbiting in space, when active micro-organisms can be supported,” said the statement.
Micro-organisms could use liquid water to colonize the comet – infiltrating cracks in the ice and “snow” during warmer periods when the cosmic wanderer is nearer the Sun, the duo said.
“Organisms containing anti-freeze salts are particularly good at adapting to these conditions and some could be active at temperatures as low as minus 40 degrees Celsius (minus 40 degrees Fahrenheit).”
Sunlit areas of the comet already approached this temperature last September, when it was about 500 million kilometers (310 million miles) from the Sun, and emitting weak jets of gas.
Comets follow elliptical orbits around the sun, and warm as they draw closer, causing a process of solid-to-gas transformation called sublimation, which is what gives them their spectacular tails.
As 67P approaches its closest point to the sun, about 185 million km on August 13, “the micro-organisms should become increasingly active,” the pair speculated.
Read more at Discovery News
This goes against the traditional assumption that gills first evolved so fish could get more oxygen as they became bigger and more active, say researchers in a recent issue of Scientific Reports.
“When we think of the gill we automatically associate it with a human lung,” said co-author Dr Jodie Rummer, a fish physiologist at James Cook University in Townsville.
“So the common thought has always been that perhaps the first reason a water breather needed to evolve a gill is to get oxygen.”
According to this so-called oxygen hypothesis, as organisms got fatter and more active, they needed more oxygen to sustain a higher metabolism.
A lot less oxygen dissolves in water than in air. While slow-moving, slim-lined fish could get away with absorbing oxygen through their thin skin, more active fish tended to be thicker-skinned (for protection) so they had to find more effective ways to get their oxygen.
The intricate folds of the gill provided the perfect solution. They had an immense surface area to allow oxygen to be absorbed into the fish’s bloodstream.
But Rummer and colleagues’ study of hagfish challenges the assumption that getting oxygen was the driver for fish developing gills.
Hagfish have lurked on the deep ocean floor for millions of years and are actually the closest living ancestor of the first fishes, says Rummer.
The thing is they are not your typical active thick-skinned big fish.
They are eel-like scavengers that generally lie around and the most active they get is when they use their rasping teeth to burrow into a sunken decaying carcass — playing a key role in recycling ocean nutrients.
Given their body shape, skin type and low metabolism, they can absorb quite enough oxygen through their skin. Studies have shown they get 80 to 90 per cent of the oxygen they need this way.
So, the question, asked Rummer and colleagues, was what did these ancestral hagfish use their gills for? And could this shed light on why gills evolved in the first place?
As part of an ongoing study of the mechanisms used by different fish to cope with ocean acidification, Rummer and colleagues tested what happened when hagfish were put in a highly acid environment.
Their findings show these ancient fish are capable of withstanding higher acidity than any other species of fish studied to date.
In fact, the researchers found the main role of their gills is to regulate their body’s acidity so they can cope with an acid environment.
The researchers collected hagfish off the west coast of Vancouver Island in Canada, and exposed them to various levels of acidity, by pumping CO2 into their water.
They then took blood tests and tissue samples at various times after the fish were exposed to the increased acidity, to see how their body chemistry changed.
Previous research has found that many fish become behaviorally and physiologically affected when exposed to the kind of acidity predicted to occur in the world’s oceans by 2100.
However, when Rummer and colleagues exposed the hagfish to 50 to 60 times those levels, the fish coped quite well.
Read more at Discovery News
Jul 5, 2015
The study, published in Cell Reports on July 2, sheds light on the evolutionary biology of these extinct giants.
"This is by far the most comprehensive study to look at the genetic changes that make a woolly mammoth a woolly mammoth," said study author Vincent Lynch, PhD, assistant professor of human genetics at the University of Chicago. "They are an excellent model to understand how morphological evolution works, because mammoths are so closely related to living elephants, which have none of the traits they had."
Woolly mammoths last roamed the frigid tundra steppes of northern Asia, Europe and North America roughly 10,000 years ago. Well-studied due to the abundance of skeletons, frozen carcasses and depictions in prehistoric art, woolly mammoths possessed long, coarse fur, a thick layer of subcutaneous fat, small ears and tails and a brown-fat deposit behind the neck which may have functioned similar to a camel hump. Previous efforts to sequence preserved mammoth DNA were error-prone or yielded insights into only a limited number of genes.
To thoroughly characterize mammoth-specific genes and their functions, Lynch and his colleagues deep sequenced the genomes of two woolly mammoths and three Asian elephants -- the closest living relative of the mammoth. They then compared these genomes against each other and against the genome of African elephants, a slightly more distant evolutionary cousin to both mammoths and Asian elephants.
The team identified roughly 1.4 million genetic variants unique to woolly mammoths. These caused changes to the proteins produced by around 1,600 genes, including 26 that lost function and one that was duplicated. To infer the functional effects of these differences, they ran multiple computational analyses, including comparisons to massive databases of known gene functions and of mice in which genes are artificially deactivated.
Genes with mammoth-specific changes were most strongly linked to fat metabolism (including brown fat regulation), insulin signaling, skin and hair development (including genes associated with lighter hair color), temperature sensation and circadian clock biology -- all of which would have been important for adapting to the extreme cold and dramatic seasonal variations in day length in the Arctic. The team also identified genes associated with the mammoth body plan, such as skull shape, small ears and short tails.
Of particular interest was the group of genes responsible for temperature sensation, which also play roles in hair growth and fat storage. The team used ancestral sequence reconstruction techniques to "resurrect" the mammoth version of one of these genes, TRPV3. When transplanted into human cells in the laboratory, the mammoth TRPV3 gene produced a protein that is less responsive to heat than an ancestral elephant version of the gene. This result is supported by observations in mice that have TRPV3 artificially silenced. These mice prefer colder environments than normal mice and have wavier hair.
Although the functions of these genes match well with the environment in which woolly mammoths were known to live, Lynch warns that it is not direct proof of their effects in live mammoths. The regulation of gene expression, for example, is extremely difficult to study through the genome alone.
"We can't know with absolute certainty the effects of these genes unless someone resurrects a complete woolly mammoth, but we can try to infer by doing experiments in the laboratory," he said. Lynch and his colleagues are now identifying candidates for other mammoth genes to functionally test as well as planning experiments to study mammoth proteins in elephant cells.
Read more at Science Daily
Ground control teams lost radio contact with New Horizons for about 80 minutes on Saturday when the spacecraft put itself in an automated safe mode after it switched over from its primary to its backup computer. What triggered the computer switch is under investigation.
With New Horizons about 3 billion miles from Earth, radio signals traveling at the speed of light take about 4.5 hours to arrive and another 4.5 hours to get the spacecraft’s return messages.
“Full recovery is expected to take from one to several days,” NASA wrote in a status report on Saturday. “New Horizons will be temporarily unable to collect science data during that time.”
On Sunday, ground controllers planned to relay a final batch of instructions to New Horizons to prepare for its July 14 flyby of Pluto, the only major body in the solar system that has not yet been visited by a robotic spacecraft.
The “encounter program” includes software to prohibit the very type of automated safe mode that New Horizons executed Saturday afternoon.
“Encounter mode short-circuits the on board intelligent autopilot so that if something goes wrong, instead of calling home for help, which is what most spacecraft do and what New Horizons does during cruise flight, it will just stay on the timeline. It will try to fix the problem, but it will rejoin the timeline because if it ‘went fetal,’ as we say, if it just called home for help, it could miss the flyby,” New Horizons lead scientist Alan Stern told Discovery News before Saturday’s problem.
Read more at Discovery News