A new paper by a team of researchers led by Karel Matous, College of Engineering Associate Professor of Computational Mechanics in the Department of Aerospace and Mechanical Engineering at the University of Notre Dame, describes how an accurate statistical description of heterogeneous particulate materials, which is used within statistical micromechanics theories, governs the overall thermo-mechanical properties. This detailed statistical description was computed using a novel adaptive interpolation/integration scheme on the nation's largest parallel supercomputers. Quantifying the morphology of many-body systems has applications in many scientific fields at a variety of length scales from molecular configurations up to structural composites and celestial bodies.
"For centuries, great minds like Kepler, Maxwell and Einstein have investigated the statistical characterization of many-body systems and the implications of small-scale structures on the macroscopic transport and mechanical properties," Matous said. "For the first time, we predicted the properties of granular Platonic solids (crystalline) packs and discovered a significant shape effect in their overall thermo-mechanical behavior. Based on our work, a large class of materials with arbitrary inclusions can now be easily studied."
The research is part of the Matous group's data-driven (image-based) multi-scale modeling strategy, where computations are guided by micro-structural experimental data.
"In my research, I study heterogeneous and multifunctional materials in extreme environments by computational and experimental means," Matous said. "These materials are essential in our daily lives and are utilized in bioengineering, the automotive and aerospace industries, micro-electro-mechanical systems (MEMS) and other applications. Heterogeneous multifunctional materials fill several pivotal roles, including structural support, self-healing capability, power generation and storage, stress mitigation and bio-filtration, just to name a few.
"These seemingly simple and elegant material functions are governed by a plethora of physics, mechanics and chemistry that test our understanding of microstructure-statistics-property relations and our capacity to tune properties at will. Many of these materials can be better understood if higher-order statistical information is retained in their well-resolved multi-scale analysis. My goal is to advance detailed understanding of mechanics and materials science through developing microstructure-statistics-property relations that can aid the development of new materials."
Matous notes that the next step in this line of work is to understand the effect of material interfaces and anisotropy (directionally dependent material behavior).
Read more at Science Daily
Apr 18, 2015
Fruit fly studies shed light on adaptability of nerve cells
Changes in the functional connections between neurons -- 'synapses' -- contribute to our ability to adapt to environmental changes. However until now, little was known about the signalling underlying such 'synaptic plasticity'. Now, investigations of fruit flies by researchers at the German Center for Neurodegenerative Diseases (DZNE), Tokyo Tech, the National Institute of Genetics in Japan, and the European Neuroscience Institute in Germany reveal details of the mechanisms behind synaptic plasticity.
"The synaptic changes that we have identified might reflect an innate neuronal property that leads to protection from excessive stimuli," explains Dr. Atsushi Sugie, the study's lead author and Postdoc at DZNE. "By enhancing this property, we might be able to protect neurons from degeneration or cell death."
Recent studies have suggested that changes in a region at the presynaptic membrane, described as the active zone, control synapse function. The research teams based in Germany and Japan exposed living fruit flies -- the commonly studied Drosophila -- to different light regimes and then compared the active zones in the photoreceptors.
T-shaped structures at the presynaptic membrane tether synaptic vesicles and control the release of neurotransmitters to the postsynaptic neuron. By tagging proteins that are crucial to these T-shaped structures the researchers revealed a drop in a subset of active zone proteins, while others remained unchanged. Further, they found that corresponding to the loss of structural proteins, the number of T-shaped structures was also reduced.
Read more at Science Daily
Apr 17, 2015
Monkey Presumed Extinct Appears in Congo Forest
Until this year, scientists hadn't seen the Bouvier's red colobus monkey in the wild since the 1970s. The small primate lives in groups in swampy forests along the Congo River, in the Republic of the Congo. Hunting and logging decimated its population, leading some scientists to suggest the monkey was extinct.
Now, independent explorers have rediscovered the rare monkey. The researchers, Lieven Devreese of Belgium and Gaël Elie Gnondo Gobolo of the Republic of the Congo, set off in February to track down the elusive species. Their expedition was supported by donations collected through the crowdfunding website Indiegogo, and funding from the Wildlife Conservation Society.
"Our photos are the world's first [of the monkey], and confirm that the species is not extinct," Devreese said in a statement.
There are several species of red colobus monkey. Until now, scientists only knew of the Bouvier's red species from a few museum specimens collected more than 100 years ago.
This particular colobus monkey shows little fear of humans — one reason it is so vulnerable to bushmeat hunters. Instead of fleeing hunters or curious scientists, the monkeys gaze at them from the trees. This makes the large groups easy pickings for the bushmeat trade, according to the Wildlife Conservation Society.
"Thankfully, many of these colobus monkeys live in the recently gazetted national park and are protected from threats such as logging, agriculture and roads, all of which can lead to increased hunting," Fiona Maisels, a biologist and expert on Central Africa for the Wildlife Conservation Society, said in the statement.
To find the Bouvier's red colobus monkey, Devreese and Gobolo asked locals to describe local monkeys and their calls. This helped narrow down where remaining colobus groups might live. The researchers started in the town of Owando, and then hired a dugout canoe in Makoua to traverse the Likouala River.
Read more at Discovery News
Man With Metal Detector Finds Roman-Era Grave
The grave likely belonged to a wealthy individual, said Keith Fitzpatrick-Matthews, the archaeology and outreach officer for the North Hertfordshire District Council. Once Fitzpatrick-Matthews and his colleagues located the grave, they also found evidence of a nearby building, likely a shrine or temple, attached to a villa.
The man with the metal detector, Phil Kirk, found the grave in a field in Kelshall, a small village located between London and Cambridge. He had once found a Roman coin in the same field, and had a hunch that there were more Roman artifacts nearby, Fitzpatrick-Matthews said.
In October 2014, Kirk hit the jackpot. His metal detector led him to a buried bronze jug that stood roughly 10 inches (25 centimeters) tall. Next, he pulled out a bronze patera (a dish used for pouring wine or blood libations) and two other jugs.
Elated with what he had found, Kirk contacted local experts and told them about the findings. They returned to the spot later that month and in November and found even more artifacts: a bronze pin, an iron lamp, glassware and bottles of different shapes, including octagonal, hexagonal, rectangular and square, Fitzpatrick-Matthews said.
The hexagonal bottle held an unusual and macabre surprise.
"It quickly became apparent that the large hexagonal bottle was stuffed full with cremated bone," said Fitzpatrick-Matthews, who hadn't realized they were digging into a grave. "Suddenly, that explained everything. We were looking at a wealthy burial."
The entire grave measures about 6.2 feet by 5.2 feet (1.9 meters by 1.6 meters), and contains a plethora of Roman artifacts. They found hobnails, which are small iron nails used on the soles of leather sandals. The sandals had straps that people would tie around their legs, but the sandals must have decayed over the ages. Only the hobnails remained.
"The idea of providing footwear in a Roman grave is that the journey to the underworld, taken by the soul after death, is taken on foot to the River Styx, where you're ferried across," Fitzpatrick-Matthews told Live Science. "It's a walking journey, so you need a pair of footwear. Anybody who could afford it was buried with their best sandals."
Grave date
The archaeologists also found mosaic glass plates, possibly from Egypt or western Europe; a small piece of lava; and the remains of a wooden box containing two glass cups. A silver coin, called a denarius, sat inside the box and likely slowed the wood's decomposition, Fitzpatrick-Matthews said. The coin features Emperor Trajan, who ruled Rome from A.D. 98 to A.D. 117.
A second coin helped them date the grave. The worn bronze coin sat inside the cremation urn. It likely served as payment for Charon, the man thought to ferry people across the River Styx, Fitzpatrick-Matthews said. Emperor Marcus Aurelius issued the coin in the A.D. 170s, he said.
"You never find these things in Roman burials, except in this one," Fitzpatrick-Matthews said. "The fact that it's worn means it was a good 20 to 30 years old by the time it got into the ground, which gives us a really nice date for the burial ground — about 200."
"Everything is absolutely perfect, except for this wretched coin of Trajan," which is about 100 years younger than the other artifacts, he said. "Who knows what it's doing there. It may have been completely accidental, and have fallen into the box without anybody really noticing."
Field archaeology
The entire grave was lined with flint, which partly smashed the artifacts under its weight, but also preserved the burial. The farmer who owns the field recalled his family noticing that area, and how the plow was unable to dig into the earth there.
The newly discovered grave fits with other clues of an earlier civilization on the farmer's property. In 1954, the farmer's family found Roman pottery in the field and donated it to a local museum.
In 2013, a circular hole about 23 feet (7 m) deep suddenly appeared in the field. Fitzpatrick-Matthews remembers looking at the hole, about 3.2 feet (1 m) in diameter, and realizing that it was the remains of a Roman well.
Now, having found the grave, the group decided to look for more clues. They found postholes, suggesting the grave neighbored a building, probably a shrine or a temple, which was attached to a villa.
"Whoever had this burial was quite clearly extremely wealthy. They've been buried with the second-century equivalent of bling," Fitzpatrick-Matthews said, referring to the lavish artifacts.
Read more at Discovery News
Tribe Found to Host Amazing Array of Bacteria
Because the collection of bacteria, or microbiome, from people living in industrialized countries is about 40 percent less diverse, the scientists suspect that certain aspects of a more urban lifestyle could be reducing the diversity of the trillions of bacteria that live on and in our bodies.
“We have found unprecedented diversity in fecal, skin, and oral samples collected from the Yanomami villagers,” Maria Dominguez-Bello, an associate professor of medicine at NYU Langone Medical Center, said in a press release. She is the senior author of the study, which is published in the latest issue of the journal Science Advances.
The Yanomami are believed to have lived in total seclusion from the outside world until 2009, when they were first contacted by a medical expedition. They are among a rare population of people who are unexposed to modern antibiotics.
Dominguez-Bello continued, “Our results bolster a growing body of data suggesting a link between, on the one hand, decreased bacterial diversity, industrialized diets, and modern antibiotics, and on the other, immunological and metabolic diseases — such as obesity, asthma, allergies, and diabetes, which have dramatically increased since the 1970s.”
She added, “We believe there is something environmental occurring in the past 30 years that is driving these diseases. We think the microbiome could be involved.”
She and her team analyzed bacterial samples collected and preserved from 34 of the known 54 Yanomami villagers. Among the volunteers, 28 gave skin and oral swab samples, while 11 gave fecal samples.
Bacterial DNA from the Yanomami was then compared to samples from populations in the United States, as well as to samples from the Amazonian Guahibo Amerindians in Venezuela and residents of rural Malawian communities in southeast Africa. The latter communities represent tribal populations with more exposure to Western culture than the Yanomami, who have subsisted by hunting and gathering for hundreds of generations.
“There is a gradient of diversity in feces and skin that is inversely proportional to exposure to antibiotics and processed foods,” explained co-author Jose Clemente, who is an assistant professor of genetics and genomics at the Icahn School of Medicine at Mount Sinai. “Even minimal exposure greatly decreases diversity and removes potentially beneficial bacteria from our microbiome.”
Among the Yanomami skin samples, the researchers found no single dominant type of bacteria. This was in contrast to the U.S. skin samples, which showed lower diversity and relatively higher proportions of Staphylococcus, Corynebacterium, Neisseriaceae, and Propionibacterium. While these bacteria are common and usually harmless, they can cause serious infections, such as the well know “staph infections” that can be difficult to treat.
A genetic analysis of gut and oral bacteria also revealed that the Yanomami villagers had bacteria containing genes coding for antibiotic resistance. The bacterial genes conferred resistance not only to natural antibiotics found in the soil, but also to synthetic antibiotics.
“During the 1940s and 1950s, in the heyday of pharmaceutical antibiotic development, most antibiotics were derived from naturally occurring bacteria in the soil,” said co-author Gautam Dantas, who is an associate professor of pathology, immunology, and biomedical engineering at the Washington University School of Medicine.
“So, we would expect that natural resistance to antibiotics would emerge over millions of years of evolution,” he added. “We didn’t expect to find resistance to modern synthetic antibiotics. The silenced antibiotic-resistant genes show that you don’t need exposure to antibiotics to possess antibiotic-resistant genes.”
Read more at Discovery News
Chubby Little ‘Sea Pig’ Tastes More Like Poison Than Bacon
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| Regular pigs may roll around in mud, but sea pigs eat it. Om nom nom. |
Dive deeper, though, down past 3,000 feet, and you’ll find a variety of sea cucumber that’s living the good life—relatively speaking, that is. These are the little-studied sea pigs, half a dozen species in the genus Scotoplanes that do indeed look a bit like swine, if swine had way too many legs and ate mud instead of rolling around in it. Compared to their shallow-water cousins, sea pigs don’t have nearly as many predators, so they don’t have to bother dropping their guts out the back end. And good on ‘em for that, really.
Now, when you think sea cucumbers, you probably think of a tube of flesh, whereas the sea pig would appear to have limbs. In fact, these are known as tube feet, and while they’re super elongated in the sea pig, they’re found in other sea cucumbers too, plus their echinoderm compatriots, including starfish and sea urchins. These tube feet are connected to a “water vascular system”—that is, echinoderms have a ton of water coursing through them. That water helps give the sea pig its shape, while muscles in the legs allow it to wander around in search of food. Unfortunately, their body wall is also quite delicate: Catch one in a net and it’ll likely disintegrate, and it’s somewhat difficult to study a puddle of goo.
And those antenna-like things on top of the sea pig? Well, those are technically feet too, but they’re not there so the creature can keep walking if it flips over—though, let’s face it, that would be pretty sweet. No, these are thought to be specially adapted to help the sea pig find food in the pitch-blackness. “The animal can sort of smell areas of mud which have higher organic content,” says marine biologist David Pawson of the National Museum of Natural History. “And so you often find them in swarms, in great herds actually concentrated on areas of mud where there’s a high organic content.”
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| Unlike regular pigs, sea pigs are translucent. But I guess a pig ghost would be translucent. Doesn’t count though. |
For this they’re equipped with around 10 tentacles—depending on the species—each with smaller structures that function like fingers. Planting these in the mud as they amble along, the sea pigs alternate moving the grub-filled tentacles to the mouth, all while facing against the current to get a whiff of any food “upstream.” The real bonanza, though, is when a whale carcass lands on the seafloor. As it rots into the sediment, hordes of sea pigs will scoot around it, gathering up the nutritious mud.
When they’re not gobbling marine snow or the occasional whale juice, sea pigs are going after all kinds of microbes on the seafloor. Which is just as well, because such microbes are consuming a whole lot of oxygen down there. When the sea pigs pass this microbial mud through their digestive system, they of course absorb all the good nutrients, but also themselves end up adding oxygen back into the muck and pooping it out on the seafloor. “They’re like earthworms,” says Pawson. “They sort of process the deep-sea mud and make it livable for other animals because they’ve increased the amount of available oxygen in it.”
Respiratory Trees, Self-Evisceration, and Other Things Sea Pigs Ain’t Got Time For
When it comes to breathing oxygen, sea pigs again betray their weirdness. Remember those shallow-water species of sea cucumber that have fish climb into their bums? Well, sea cucumbers also breathe through those bums, using a so-called respiratory tree. This is what those parasitic fish swim up, where they get a nice home and a constant supply of water to boot. But even if such fish lived in the depths, the sea pigs wouldn’t have to worry about them. They’re missing the respiratory tree. Instead, they breathe through their exceedingly thin skin, exchanging oxygen with the surrounding water right through their body wall.
Also setting sea pigs apart from other sea cucumbers: They don’t blow their guts out of their backsides when harassed. And that, according to Pawson, is probably because they don’t tend to get harassed that much. Compared to something like a reef, where all manner of predators can make life miserable for sea cucumbers, the deep is relatively safe. And think about just what a traumatic experience eviscerating yourself is (OK maybe don’t). Sure, the sea cucumber grows it all back eventually, but that takes a tremendous amount of energy. And in the deep, where food isn’t exactly plentiful, the sea pig probably wouldn’t have the resources to drive this regeneration.
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| Is a herd of sea pigs kinda cute, or is it just me? No? OK, I’ll sit down now. |
Still, for all science knows about the sea pigs (which, all things considered, is a good amount, given that it’s a deep-sea species), there’s much to be learned. How they mate is still a mystery, as is how long they live. “They might live for 10 years, or they might live for 100 years,” says Pawson. They leave tracks, which is a nice little clue, but “in some parts of the world’s oceans the rate of sedimentation, stuff falling from above down to the seafloor, is so slow that the tracks you’re looking at, even though they look fresh, they might be 100 years old.”
Read more at Wired Science
Apr 16, 2015
Julius Caesar May Have Suffered Mini Strokes, Not Epilepsy
Ancient sources report that Julius Caesar (100-44 BC) had episodes of vertigo, dizziness and limb weakness.
The dictator of the Roman empire famously suffered falls during his campaigns in Spain and Africa. The first attack occurred in 46 BC in Thapsus, modern Tunisia, and the second in Cordoba, Spain, when he was over 50 years of age.
The Roman historian Suetonius (69-after 122 AD) claimed that “towards the end he was subject to sudden fainting fits and nightmares as well,” and called his disease “morbus comitialis.”
Caesar’s condition was also reported by the Greek historian Plutarch (about 46-120 AD). In his biography of the Roman general, he wrote that Caesar collapsed in Thapsus and was carried to safety to a “neighboring tower where he stayed quietly during the battle.”
Suetonius and Plutarch’s accounts contributed to produce a diagnosis of epilepsy which has prevailed for centuries.
“The theory that Caesar was epileptic appears not to have very solid philological foundations. If carefully re-examined, the facts appear to suggest a simpler and more logical diagnosis of stroke,” Francesco M. Galassi, an MD at Imperial College London, told Discovery News.
Detailing their review in the journal Neurological Sciences, Galassi and colleague Hutan Ashrafian, a surgeon at the college, argue that most studies have focused on the origin of Caesar’s epilepsy, but virtually none has questioned the assumption that he was epileptic.
“Suetonius uses the words ‘morbus comitialis’, a very general definition, not necessarily meaning epilepsy,” Galassi said.
According to Galassi and Ashrafian, the symptoms reported in Caesar’s life — falls, headache, vertigo, giddiness — are consistent with him having multiple mini-strokes.
“Furthermore, Caesar also suffered from other symptoms including depression and personality changes (exampled by emotional lability when listening to a moving oration by Cicero) which may also be consistent with cerebrovascular disease,” Galassi and Ashrafian wrote.
Another attack might have occurred when Caesar failed to stand up as senators honored him. On that occasion, he reported symptoms of headaches, vertigo and later mentioned giddiness and insensibility.
Considered one of the greatest military leaders of all time, Caesar first conquered territory in Britain, Gaul (now France), and Spain. He crossed Italy’s Rubicon River, giving rise to the five-year-long civil war that left him dictator of Rome.
By 45 BC, Caesar controlled a vast territory that later was the Roman Empire. But his rule was cut short when conspirators, who feared he had too much power, stabbed him to death in the Senate building.
Until now, cardiovascular explanations for Caesar condition have been largely ruled out because until his death he was apparently otherwise well in private and state affairs.
“Even if Caesar participated in an active lifestyle and may have benefited from the background of a Mediterranean diet, there is the added possibility of genetic predisposition towards cardiovascular disease,” the researchers wrote.
Indeed, Pliny the Elder reports that both Caesar’s father and another forefather died suddenly without any real explanation while putting on their shoes.
“This has been explained in terms of SUDEP (sudden unexpected death in epilepsy) but it is much more logical and less complicated to think of these deaths in terms of cerebrovascular disease or lethal myocardial infarction,” Galassi said.
Read more at Discovery News
NASA Probe to Crash Into Mercury in 2 Weeks' Time
Out of fuel, the robotic Mercury Surface, Space Environment, Geochemistry and Ranging, or MESSENGER, probe on April 30 will succumb to the gravitational pull of this strange world that has been its home since March 2011. The purpose of the mission, originally designed to last one year, is to collect detailed geochemical and other data that will help scientists piece together of how Mercury formed and evolved. Mercury is one of four versions of rocky planets in the solar system, along with cloud-shrouded Venus, life-friendly Earth and dry, cold Mars.
After two mission extensions, scientists got a six-week bonus run after engineers figured out a way to vent helium used to pressurize the spacecraft’s fuel tank as a way to gain some altitude. MESSENGER’s last boost, scheduled for April 24, will hike the probe’s altitude from about six miles to about 12 miles above the planet’s surface, adding another six days -- roughly 40 orbits -- for studies.
"MESSENGER is going to create a new crater on Mercury sometime in the near future ... let's not be sad about that," NASA associate administrator John Grunsfeld said Thursday, kicking off an event to celebrate the mission's science results.
MESSENGER’s last days have been among the mission’s most rewarding, including details on the surprising discovery that Mercury, despite being so close to the sun, has ice inside craters near its poles, regions that are never directly exposed to sunlight.
Analysis of images shows a dark, possibly carbon-rich material overlying ice in one crater, named Fuller after architect Richard Buckminster Fuller. That could have happened when an icy comet or carbon-rich asteroid smashed into Mercury.
MESSENGER also has found bright spots inside some craters, which turned out to be shallow, recently formed depressions known as hallows.
"Hallows are a land form we didn't expect. They are some of the youngest features on the planet, and this speaks to some unstable material whose identity we are still working out," said MESSENGER's lead scientist Sean Solomon, with Columbia University.
Similar features have been found on the water-rich dwarf planet Ceres, which is about to become the focus of detailed studies by NASA’s orbiting Dawn spacecraft.
Read more at Discovery News
Enceladus Spreads Ghostly Ice Tendrils Around Saturn
Using images from NASA’s Cassini mission, the source of these tendrils have been tracked down and they originate from the icy moon’s famous geysers. But even better than that, scientists have been able to track the specific tendril shapes down to the specific geysers that produce them.
“We’ve been able to show that each unique tendril structure can be reproduced by particular sets of geysers on the moon’s surface,” said Colin Mitchell, a Cassini imaging team associate at the Space Science Institute in Boulder, Colo., and lead author of a paper published int he Astrophysical Journal.
Mitchell’s team combined the high-resolution Cassini data with computer simulations to track the trajectories of the ice grains to individual geysers blasting through giant fissures in Enceladus’ icy crust. Consisting of tiny ice particles, dust and organic molecules, the geysers provide a tantalizing view into the components of the sub-surface ocean that is theorized to exist below the moon’s thick icy crust.
From Enceladus, these huge features reach tens of thousands of miles away into Saturn’s E ring, supplying it with icy particles. The researchers were able to deduce the size of the ice particles in the E-ring and the tendrils, measuring them to “no smaller than about a hundred thousandth of an inch,” according to a NASA news release. This provided a direct link from Enceladus’ geysers to one of Saturn’s outer rings.
Throughout Cassini’s studies of Enceladus’ tendrils, variations in their shape and size have become apparent, probably due to the tidal squeezing regulating the icy output from the moon’s contracting and expanding fissures. Further work is needed to verify this correlation, however.
A cool implication of this work is that understanding the dynamics of Enceladus’ tendrils may provide an accurate measure on how ice is leaving the small moon and how much is making it to the E ring. This, in turn, may help planetary scientists understand the lifetime and evolution of Enceladus’ sub-surface ocean.
“As the supply lanes for Saturn’s E ring, the tendrils give us a way to ascertain how much mass is leaving Enceladus and making its way into Saturn orbit,” said Carolyn Porco, team leader for the imaging experiment and a coauthor on the paper. “So, another important step is to determine how much mass is involved, and thus estimate how much longer the moon’s sub-surface ocean may last.”
Read more at Discovery News
Could Next-Gen Hubble Telescope Seek Out Alien Life?
Hubble, a joint project of NASA and the European Space Agency (ESA), blasted off aboard the space shuttle Discovery on April 24, 1990. Spacewalking astronauts fixed a serious problem with the telescope's optics in 1993, and Hubble has been transforming astronomers' understanding of the cosmos — and bringing gorgeous images of the universe into laypeople's lives —ever since.
"It has really allowed people to participate in the excitement of discovery," said Mario Livio, an astrophysicist based at the Space Telescope Science Institute in Baltimore, which operates Hubble's science program.
"Hubble images have become part of our culture," Livio told Space.com. "I regard this as an incredible contribution."
While the venerable Hubble will likely be able to keep studying the heavens for at least five more years, it's now time to start planning out a future space telescope that will tackle the next big frontier in space science, Livio says — the search for signs of life beyond our neck of the cosmic woods.
"Hubble has taught us that to answer the most intriguing questions in astrophysics, we must think big and put scientific ambition ahead of budgetary concerns," he wrote in a commentary piece published online today (April 15) in the journal Nature.
"In my view, the next priority should be the search for life beyond our solar system," Livio added. "A powerful space telescope that can spot biological signatures in the atmospheres of Earth-like exoplanets would be a worthy successor."
Hubble's immediate successor is NASA's $8.8 billion James Webb Space Telescope (JWST), which is due to launch in 2018. The infrared-optimized JWST will be able to study the atmospheres of some nearby planets discovered by the Transiting Exoplanet Survey Satellite, or TESS, which NASA aims to launch in 2017.
The agency is also developing a potential space-telescope mission called WFIRST/AFTA (short for Wide Field Infrared Survey Telescope–Astrophysics Focused Telescope Assets). WFIRST/AFTA, which could launch around 2024 if it gets the final go-ahead, would continue the hunt for biosignatures, among several other major tasks.
But Livio has something more ambitious in mind: A space telescope with a primary mirror at least 39 feet (12 meters) wide, with vision 25 times sharper than that of Hubble. (For comparison, the main mirrors of Hubble, WFIRST/AFTA and JWST are 7.9 feet [2.4 m], 7.9 feet and 21.3 feet [6.5 m] wide, respectively.)
Such a powerful instrument could scan the skies of enough Earthlike exoplanets to place "meaningful statistical constraints" on the abundance or rarity of alien life throughout the Milky Way galaxy, according to Livio.
"A large sample of planets — around 50 — would have to be tested," he wrote in the Nature commentary. "Calculations show, for example, that if no biosignatures are detected in more than about three dozen Earth analogues, the probability of remotely detectable extrasolar life in our galactic neighborhood is less than about 10 percent."
Read more at Discovery News
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