Sep 28, 2013
This is the first known marine mammal mass stranding event to be closely associated with what are known as high-frequency mapping sonar systems; but it is merely the latest in a long line of incidents in which industrial noise in the ocean has been implicated in deaths and injuries to marine mammals, and specifically cetaceans.
One area of particular focus is the use of active sonar by the United States and other navies. In 2004, the Scientific Committee of the International Whaling Commission concluded that “there is now compelling evidence implicating military sonar has a direct impact on beaked whales.” In 2001, the U.S. Navy acknowledged that its active sonar played a role in the stranding deaths of 14 beaked whales, two minke whales, and a dolphin in the Bahamas in 2000. Necropsies of the beaked whales revealed that the animals had suffered acoustic trauma resulting in hemorrhaging around the brain, in the inner ears, and in the acoustic fats located in the head that are involved in sound transmission.
Then there is the use of air guns to conduct seismic surveys for oil and gas deposits in the sea bed. Because of concerns that the intense sounds from these air guns can either cause physical damage to cetaceans or cause them to flee, the U.S. Marine Mammal Protection Act requires visual observers to examine the area for marine mammals for a period of at least 30 minutes. Assuming the coast is clear, the survey must ramp up slowly by firing first one seismic gun and then others over a period of between 20 and 40 minutes. However, if a whale or other marine mammal appears within an exclusion zone of 500 meters from the center of the seismic array, the operation must shut down, and visual examination must resume for 30 minutes.
The presence of seismic survey vessels was initially considered a likely reason for the 2008 Madagascar incident, not least because melon-headed whales are an open-ocean species that had never before (and have never since) been recorded in the island’s shallow tidal Loza Lagoon estuarine system; it seemed reasonable to infer that something had startled them into entering the area. Experts with the International Fund for Animal Welfare and the Wildlife Conservation Society attempted to rescue the whales, but with minimal success, largely because of the large distance (over 69 km/43 miles) from the point where they were becoming stranded to the open ocean.
Following the incident, the International Whaling Commission facilitated a review of the evidence and an Independent Scientific Review Panel (ISRP) of five experts was invited to examine that evidence. The ISRP has just published its findings, and concluded that air gun blasts from seismic survey vessels in the area were not to blame, as they in fact took place several days after the incident.
However, a vessel using a different type of surveying technique — a high-power 12 kHz, multi-beam echosounder system (MBES) — was, says the report, “moving in a directed manner down the shelf-break the day before the event, to an area approx. 65 km offshore from the first known stranding location. The ISRP deemed this MBES use to be the most plausible and likely behavioral trigger for the animals initially entering the lagoon system.”
Most attention has focused on the likely impacts of mid-frequency and low-frequency sound sources, because of their greater propagation through water; it is possible, the ISRP noted, that high-frequency sounds like the MBES also affect some cetaceans more than previously realized but that, under normal circumstances, those cetaceans swim away. It was to the considerable misfortune of those melon-headed whales five years ago that they were in the wrong place at the wrong time, and that when they turned tail and fled, they swam into an inhospitable area from which there was no escape.
Read more at Discovery News
With its one-meter mirror, Sunrise is the largest solar telescope to fly above the atmosphere. The telescope weighed in at almost 7,000 pounds and flew some 20 miles up in the air. Sunrise was launched from Kiruna in the north of Sweden and, after five days drifting over the Atlantic, it landed on the remote Boothia Peninsula in northern Canada, gathering information about the chromosphere throughout its journey.
The temperature in the chromosphere rises from 6,000 K/10,340 F/5,272 C at the surface of the sun to about 20,000 K/ 35,540 F/19,730 C. It's an area that's constantly in motion, with different temperatures of hot material mixed over a range of heights, stretching from the sun's surface to many thousands of miles up. The temperatures continue to rise further into the corona and no one knows exactly what powers any of that heating.
"In order to solve this riddle it is necessary to take as close a look as possible at the chromosphere -- in all accessible wavelengths," said Sami Solanki, the principal investigator for Sunrise from the Max Planck Institute. Sunrise used an instrument that was able to filter particular ultraviolet wavelengths of light that are only emitted from the chromosphere.
Sunrise's extremely high-resolution images in this wavelength painted a complex picture of the chromosphere. Where the sun is quiet and inactive, dark regions with a diameter of around 600 miles can be discerned surrounded by bright rims. This pattern is created by the enormous flows of solar material rising up from within the sun, cooling off and sinking down again. Especially eye-catching are bright points that flash up occasionally -- much richer in contrast in these ultraviolet images than have been seen before. Scientists believe these bright points to be signs of what's called magnetic flux tubes, which are the building blocks of the sun's magnetic field. The magnetic field is of particular interest to scientists since it is ultimately responsible for all of the dynamic activity we see on our closest star.
Read more at Science Daily
Sep 27, 2013
On Monday afternoon (Sept. 23), a female monkfish at the New England Aquarium in Boston laid her third egg veil this year.
The veil looks something like a 60-foot-long (18 meters) sheet of delicate bubble wrap, covered in about a million pinhead-sized eggs waiting to be fertilized.
"In the wild, when the female is swimming around releasing the egg veil, the male is swimming around her and as they intertwine, the male releases its sperm," aquarist Bill Murphy, of New England Aquarium, told LiveScience.
The aquarium's female fish doesn't have a male counterpart, so these eggs won't result in any offspring. (Murphy said he tried putting two of the fish in one tank before, but they are a solitary, predatory species, and the pairing didn't work out.) For now, visitors will be able to see veil float around in the goosefish's tank until it starts to rot.
Murphy said he didn't catch the veil-laying on Monday, but in the weeks leading up to the moments-long event, there are usually signs that a sheet of eggs is coming — namely, the fish starts looking bloated.
"She looks huge, like she swallowed a beach ball," Murphy said.
Monkfish are anglerfish that sit, partially buried, at the bottom of the ocean, attracting prey with a lure in the form of a flap of skin that looks like a small fish, Murphy said. When its victim is close enough, the monkfish opens its big mouth suddenly, creating a vacuum to suck in its prey.
Read more at Discovery News
Alston's singing mouse (Scotinomys teguina) and the Chiriqui singing mouse (S. xerampelinus) have overlapping lifestyles in the cloud forests of Costa Rica and Panama. But the tawny cousins seem to establish geographic boundaries so they can avoid competing with each other.
"A long-standing question in biology is why some animals are found in particular places and not others," study researcher Bret Pasch, a postdoctoral fellow at the the University of Texas at Austin, said in a statement. "What factors govern the distribution of species across space?"
As it turns out, a little communication between individuals affects the spread of both species as a whole.
Both species of singing mice produce vocalizations that are barely audible to humans. As video footage of the mouse-y opera from the foggy forest floor shows, the creatures throw their heads back and belt out songs in the form of rapidly repeated notes, known as trills. The Alston's mouse in the clip even looks likes it's taking a bow after its solo. (Watch Video of Singing Mouse)
Researchers already knew that the rodents sing to attract mates and repel rivals within their own species. But Pasch and colleagues found that these high-pitched tunes can serve as signals across species, too, helping males protect their turf.
Through experiments in the field and in the lab, the researchers noticed that the larger Chiriqui mice are less tolerant of heat. The creatures are typically spread throughout the cooler, higher-altitude parts of the cloud forests, and dominant Chiriqui males sing in response to potential intruders of both species, the researchers found.
Meanwhile, Alston's mice are more flexible when it comes to temperature; they will spread into cooler, higher habitats if no Chiriqui mice are around to push them out. But when an Alston's male hears the song of its larger cousin, it will stop its own singing and flee to avoid confrontation, the researchers found.
Read more at Discovery News
But why isn’t that figure 99, or even 100 percent?
It turns out that the massive report by the Intergovernmental Panel on Climate Change can say some things with absolutely certainty, or 100 percent probability. That includes findings that the planet is warming, the seas are rising and glaciers in Antarctica, Greenland and other mountain regions are melting. It also includes the fact that human activity is pushing up levels of atmospheric carbon dioxide that are the highest in 800,000 years.
But when it comes to the links between human activity and the climate, scientists have to rule out all other kinds of natural variability, according to Christopher Field, a climate scientist at the Carnegie Institution for Science who worked on the IPCC report.
“It’s a 95 percent probability that more than half of the climate change is from human actions,” Field said. “The 95 percent leaves only a sliver of doubt. In most of science when we say were convinced, we say less than 1 in 20 chance. So that’s one of the reasons the 95 percent standard is appropriate here.”
The 5th IPCC report has a higher confidence that the 4th report, which stated the same cause and effect at 90 percent. That’s because measurements of the Earth’s climate are more accurate, more widespread and cumulatively larger than the last report, Field said.
Still, the Earth’s atmosphere is not a test tube. There are other factors that come into play, such as the natural variability of the climate over time, as well as effects of volcanic gasses.
In fact, the 95 percent figure cited in the summary of the four-part IPCC assessment applies to the overall report, not individual statements on the human impacts of climate change, according to Shang-Ping Xie, another report author and climatologist at the Scripps Institution of Oceanography in La Jolla, Calif.
Read more at Discovery News
As material from the large, low-mass star is pulled into a hot accretion disk swirling around its companion and interacts with its magnetic field, powerful x-rays are emitted, detectable as a “low-mass binary” by x-ray-sensitive telescopes like NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton.
But as the neutron star absorbs material from the spinning accretion disk it gains momentum, spinning faster and faster and ramping-up its magnetic field even further. As the flow of material from the low-mass star slows, the neutron star — now spinning madly, up to 254 times a second — throws much of the material in the disk out of the system entirely. With the x-ray emitting material gone, the neutron star is free to blast jets of radio waves out into space from its poles. It’s now a millisecond pulsar, and to anything aligned with its poles it flashes in radio like a lighthouse beacon on overdrive.
Talk about dancing with the stars.
While the full transition of a low-mass x-ray binary to millisecond pulsar is a process that’s thought to take place over billions of years, IGR J18245-2452 has given astronomers evidence that switches — in both directions — can occur much more rapidly… within a period of just a few days, in fact.
It’s the first time that the transition between these particular two stages of stellar evolution has been directly observed.
“We’ve been fortunate enough to see all stages of this process, with a range of ground and space telescopes. We’ve been looking for such evidence for more than a decade,” said Dr. Alessandro Papitto, lead author of the paper published in the Sept. 26, 2013 issue of Nature.
“It’s like a teenager who switches between acting like a child and acting like an adult,” said John Sarkissian, a co-author who observed the system with CSIRO’s Parkes radio telescope in Australia.
Read more at Discovery News
Sep 26, 2013
The evidence comes from the discovery of internal clock genes that help some marine animals track the ebb and flow of the tides, according to two studies detailed today (Sept. 26) in the journals Current Biology and Cell Reports.
"The discovery of the circadian clock mechanisms in various terrestrial species from fungi to humans was a major breakthrough for biology," said Current Biology study co-author Charalambos Kyriacou of the University of Leicester, in a statement. "The identification of the tidal clock as a largely separate mechanism now presents us with an exciting new perspective on how coastal organisms define biological time."
Though the tidal clocks have only been found in two species so far, it's possible that multiple internal clocks could be widespread in sea-dwelling -- and perhaps land-dwelling -- creatures.
For years, scientists thought the circadian clock guided the tidal behavior of marine animals. In almost all land-based animals, including humans, the circadian clock orchestrates rhythmic changes in physiology and behavior based on night and day.
But for animals at sea, life is guided by the ebb and flow of the tides, caused by the moon's gravitational pull on the Earth. For instance, a crustacean called Eurydice pulchra swims out in search of food with the incoming tides, then burrows in the sand once the tide departs.
To understand how animals keep track of this ocean rhythm, Kyriacou and his colleagues caught Eurydice pulchra off the coast of Wales every season, then identified their circadian clock genes. When they turned off those genes or disrupted the circadian cycle by exposing the creatures to bright light for several days, they found that cells linked to natural sunscreens were completely thrown off.
Yet like clockwork, the crustaceans still swam out every day on 12.4 hour cycles, suggesting the creatures had a separate internal clock anchored by the tides.
"This shows that the 12.4 hour clock is independent from the circadian clock. I expect tidal rhythms in many coastal organisms will follow this rule, including insects, crabs, even plants," Kyriacou said.
In another study, researchers took a look at marine bristle worms. Bristle worms sync their spawning seasons to the waning of the moon: Most mating happens under a new moon and almost disappears during full moons.
Yet when the researchers disrupted the bristle worms circadian clocks, their monthly lunar clock still ticked on. Their lunar clocks, however, seemed to affect the timing and power of circadian-based behaviors.
Read more at Discovery News
A team of Australian scientists led by Chris Johnson of the University of Tasmania is arguing that there are serious flaws in recent work by two Brazilian researchers that exonerates humans. The pair that did that work, Matheus S. Lima-Ribeiro and José Alexandre F. Diniz-Filho of the Universidade Federal de Goiás, have answered that nope, their work isn’t perfect, but still gets humans off the hook.
“They find that in many places megafauna were apparently extinct before humans arrived; in many others, megafauna coexisted with humans for thousands of years before going extinct,” writes Johnson and company in the Oct. 2 issue of the journal Quaternary International. “They conclude that human impact made at most a minor and geographically restricted contribution to megafaunal extinction.”
Johnson argues that the Brazilians’ conclusions are off because they messed up the dating of fossils and extinctions. They re-analyzed the same data and reached the opposite conclusion: the demise of the big animals followed the arrival of humans by about one or two thousand years. That figure meshes with what models predict in terms of how long it would have taken humans to kill and consume so many animals.
But the Brazilians aren’t budging, much.
“…We are…aware that our approach is not necessarily the best, final way, either to deal with such uncertainties or to solve the puzzle of” the megafuana extinctions, the Brazilians responded, in the same issue of the journal. They go on to defend their conclusions and produce yet another analysis of the data that supports their original conclusion: that the timing is wrong for humans to have wiped out all those beasts.
Read more at Discovery News
The magnitude-7.7 earthquake was likely centered on a southern strand of the Chaman Fault, said Shuhab Khan, a geoscientist at the University of Houston. In 1935, an earthquake on the northern Chaman Fault killed more than 30,000 people and destroyed the town of Quetta. It was one of the deadliest quakes ever in Southeast Asia.
Shaking from yesterday's earthquake in Pakistan demolished homes in the Awaran district near the epicenter, according to news reports. The death toll will likely rise as survivors and emergency workers search the debris.
In the hours after the quake, a new island suddenly rose offshore in shallow seas near the town of Gwadar, about 230 miles (380 kilometers) southwest of the epicenter. Geologists with the Pakistan Navy have collected samples from the rocky pile, the Associated Press reported. From pictures and descriptions, many scientists think the mound is a mud volcano, which often erupt after strong earthquakes near the Arabian Sea. A second island has also been reported offshore of Ormara, about 170 miles (280 km) east of Gwadar, Geo News said.
"Other mud volcanoes have been triggered at this distance for similar size earthquakes," Michael Manga, a geophysicist and expert on mud volcanoes at the University of California, Berkeley, told LiveScience's OurAmazingPlanet.
Little known risk
The unexplained island may have focused unusual global attention on the earthquake, which hit in a region that frequently experiences devastating temblors.
But despite the hazards faced by millions living near the Chaman Fault, a combination of geography and politics means the seismic zone remains little studied. The Taliban killed 10 climbers, including an American, in northern Pakistan in June.
"Its location is in an area that is very difficult to do any traditional field work," Khan told LiveScience's OurAmazingPlanet. "I tried twice to submit proposals to (the National Science Foundation) and I got excellent reviews, but the review panel said I was risking my life to work in that area."
But the National Academy of Sciences felt differently. With their support, Khan and his colleagues in Pakistan and at the University of Cincinnati are now studying the fault's current and past movement. This will help the researchers forecast future earthquake risk.
"This fault has had very little work and no paleoseismology," Khan said. "It is really important."
Pakistan's deadly earthquakes owe their birth to the juncture of three colliding tectonic plates: Indian, Eurasian and Arabian. The Indian and Eurasian plates grind past each other along the Chaman Fault, triggering destructive temblors.
Earthquakes along the Chaman Fault are more frequent in the north than in the south, Khan said. Similar to California's San Andreas Fault or Turkey's East Anatolian Fault, in some spots, the massive plate boundary is not a single fracture. In southern Pakistan, the Chaman Fault splits into more than one strand, weaving a braid of many smaller faults. The differences between north and south influence the number of earthquakes.
In the past 40 years, only one quake bigger than magnitude 6.0 has jiggled southern Pakistan within 125 miles (200 km) of yesterday's shaker, according to the Incorporated Research Institutions for Seismology in Seattle.
Altogether, the strike-slip Chaman Fault spans more than 500 miles (860 kilometers), crossing through Afghanistan and Pakistan. Strike-slip faults move each side of the fracture mostly parallel to each other.
In the north, near the town of Chaman where India jabs a knuckle into Pakistan, the fault has zipped along at 33 millimeters (1.3 inches) every year for the past 38,000 years, according to a study Khan's team published Sept. 12 in the journal Tectonophysics.
"That is very fast," Khan said. "That tells me there were multiple major earthquakes in the last 38,000 years."
Many mud volcanoes
The ongoing tectonic crash in Pakistan also helps create the mud volcanoes that pop up after earthquakes there. "Whenever there is a major earthquake there are mud volcanoes," Khan said.
The spectacular mountains and roaring rivers of the Pamirs and the Himalayas deliver huge piles of wet silt and mud to the Arabian Sea. Jiggling these wet, gassy layers triggers an eruption of trapped water, Manga said. Think of liquefaction — when saturated soil loses its strength — but on a titanic scale.
The gray, dome-shaped mass offshore of Gwadar is 60 feet (18 meters) high, 100 feet (30 m) long and 250 feet (76 m) wide, a geologist with the Pakistan Navy told Geo News.
Stones on top of the pile suggest the muck roared out of the sea fast enough to carry solid rock.
Read more at Discovery News
The findings, detailed in the Sept. 26 issue of the journal Nature,have implications for extraterrestrial life as well, hinting that oxygen-generating life could arise very early in a planet's history and potentially suggesting even more worlds could be inhabited around the universe than previously thought, the study's authors said.
It was once widely assumed that oxygen levels remained low in the atmosphere for about the first 2 billion years of Earth's 4.5-billion-year history. Scientists thought the first time oxygen suffused the atmosphere for any major length of time was about 2.3 billion years ago in what is called the Great Oxidation Event. This jump in oxygen levels was almost certainly due to cyanobacteria — microbes that, like plants, photosynthesize and exhale oxygen.
However, recent research examining ancient rock deposits had suggested that oxygen may have transiently existed in the atmosphere 2.6 billion to 2.7 billion years ago.
The new study pushes this boundary back even further, suggesting Earth's atmosphere became oxygenated about 3 billion years ago, more than 600 million years before the Great Oxidation Event. In turn, this suggests that something was around on the planet to put that oxygen in the atmosphere at this time.
"The fact oxygen is there requires oxygenic photosynthesis, a very complex metabolic pathway, very early in Earth's history," said researcher Sean Crowe, a biogeochemist at the University of British Columbia in Vancouver. "That tells us it doesn't take long for biology to evolve very complex metabolic capabilities."
Ancient oxygen reactions
Crowe and his colleagues analyzed levels of chromium and other metals in samples from South Africa that could serve as markers of reactions between atmospheric oxygen and minerals in Earth's rocks. They looked at both samples of ancient soil and marine sediments from about the same time period — 3 billion years ago.
The researchers focused on the different levels of chromium isotopes within their samples. Isotopes are variants of elements; all isotopes of an element have the same number of protons in their atoms, but each has a different number of neutrons — for instance, each atom of chromium-52 has 28 neutrons, while atoms of chromium-53 have 29.
When atmospheric oxygen reacts with rock, a process known as weathering, heavier chromium isotopes, such as chromium-53, often get washed out to sea by rivers. This means heavier chromium isotopes are often depleted from soils on land and enriched in sediments in the ocean when oxygen is around. These proportions of heavier chromium were just what were seen in the South African samples. Similar results were seen with other metals, such as uranium and iron, that hint at the presence of oxygen in the atmosphere.
"We now have the chemical tools to detect trace atmospheric gases billions of years ago," Crowe told LiveScience.
'Almost certainly biological'
All in all, the researchers suggest atmospheric oxygen levels 3 billion years ago were about 100,000 times higher than what can be explained by regular chemical reactions in Earth's atmosphere. "That suggests the source of this oxygen was almost certainly biological," Crowe said.
Read more at Discovery News
The man suffered damage to his nose and an infection after a severe car accident. The infection had eaten away at the cartilage in his nose, making it impossible to for doctors to fix his original one. Instead, the team decided to grow the man an entirely new nose on his forehead, according to the Huffington Post.
But despite its extreme appearance, this method is not that different from plastic surgery techniques used all the time, said Dr. David Cangello, an attending plastic surgeon at Lenox Hill Hospital and Manhattan, Eye Ear and Throat Hospital in New York.
"I would call it a different take on a principles that we commonly use in reconstruction," Cangello said.
The man's doctors placed tissue expanders, which create space to stretch the skin, under the man's forehead, and created the rough shape of a nose, probably using screws and plates. They then harvested cartilage from his ribs to fill in the nose. Once the nose is ready, they will rotate the entire assemblage -- skin, blood vessels, cartilage and all -- and move the new nose to where his current nose sits.
That is only slightly different from current methods of nose reconstruction, Cangello told LiveScience. Though reconstructive surgeons would also put tissue expanders under the forehead skin to stretch the skin enough to cover the new nose, they would place the nose differently.
"We typically take the cartilage from the rib, and we put it right where the nose structure would already be, and we bring the skin flap over it and cover it," Cangello said.
Afterward, the doctors suture together the skin flaps of the forehead, which will usually leave a small scar.
Key blood vessels
Though it may seem like a patient might prefer to grow a new nose on a different part of the body that could be more inconspicuous, there are good reasons to use forehead skin.
"Skin that comes from another area of the face will most resemble the skin of the nose, as opposed to skin that came from another body part," Cangello said.
The forehead also has blood vessels that nourish the tissue transplant, so the surgeons don't have to disconnect and reconnect those vessels to place the nose in its correct position. If the doctors were to grow the nose on a forearm or a leg, for instance, they would have to undertake a laborious microsurgery to take the blood vessels that feed and drain the transplant.
Read more at Discovery News
Sep 25, 2013
The fish, entelognathus primordialis (meaning "primordial complete jaw"), is the oldest known animal to have face-forming jaw and cheek bones comparable to those of today's bony fishes and most terrestrial animals, including us.
"Entelognathus had a rather unprepossessing face," co-author Per Erik Ahlberg of Uppsala University told Discovery News. "The mouth was wide, the forehead low and flat, and the small, close-set and almost immobile eyes pointed forwards like a pair of car headlights."
Lead author Min Zhu, of the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology, added that entelognathus was "a placoderm, an extinct grade of primitive armored fishes."
Zhu and colleagues found the 419-million-year-old fish at Xiaoxiang Reservoir in Quijing, Yunnann, China. He said that at first it didn't seem very interesting, covered with material from the site, but when they brought it back to the lab and cleaned it up, the fish's "superb preservation," armor and facial bones became evident.
Before fish had faces like those of modern species, they looked downright bizarre, suggests Matt Friedman, a lecturer in paleobiology at the University of Oxford. Friedman, along with Martin Brazeau, authored a commentary about the new fish for Nature.
Friedman told Discovery News that some fossil jawless fishes "had broad, shovel-shaped heads with their eyes placed on top, while others had narrow bodies and skulls with their eyes on either side of the head."
Both Friedman and study co-author Brian Choo said that a handful of jawless fishes -- the eel-like lampreys and hagfishes -- are still alive today.
"They actually have a peculiar tongue-like structure that bears horny teeth, and the end of this is mobile," Friedman said. "It's very strange, a bit like the second mouth that issues from the alien in the 'Aliens' films. Lampreys are made even stranger by having a modified disc around their mouth that they use to adhere to other fishes."
It remains a mystery as to why fish evolved cheek and jaw bones. The researchers suspect that the ancestors of Entelognathus moved away from the bottom of the seafloor to spend more time in the water column. There, jaws would have helped them to catch larger and more mobile prey.
Choo further suspects that jaws might have "evolved initially for breathing, as an apparatus to control the flow of water across the gills."
For the most part, however, the fish probably hunted near the bottom of the seafloor, catching small, slow prey, such as worms. Ahlberg said that there were considerably larger fish in the same water, "including some with scary-looking teeth," which probably preyed on Entelognathus that enjoyed some degree of protection from its thick armor exterior.
Friedman and Brazeau call the new fish discovery "jaw dropping." The find suggests that the bones of the human skull and face, as well as the collarbone at the base of our necks, are remnants of ancient placoderm armor.
The discovery could also change how we view ancient marine dwellers. Previously, the ancestors of modern jawed animals were commonly portrayed as fishes with a shark-like appearance. The newly found prehistoric fish “puts a new face” on the original jawed species, Friedman and Brazeua write.
Read more at Discovery News
Researchers recently studied a collection of penis bones from an extinct species of bear in Spain. Compared with today's bears, this ancient creature, named Indarctos arctoides, had a surprisingly large penis bone that suggests it had infrequent but long-lasting sex sessions, the study found. And the females may have used penis size to assess their mates.
Human males today don't have a penis bone, formally called a bacula, but it is found in many other mammals, including chimpanzees and gorillas. Whereas humans depend on blood pressure to stiffen up their sexual member, a penis bone helps animals keep their penis reliably erect for intercourse.
Penis bones are rare in the fossil record, but researchers found five of them in the Madrid Basin in Spain that belonged to this large primitive bear, Indarctos arctoides. The bear roamed Europe during the Late Miocene (around 12 million to 5 million years ago), and the male of the species would have grown to around 584 pounds (265 kilograms), similar in size to the European brown bear.
Its bacula was, on average, 9.1 inches (23.3 centimeters) long — significantly larger than the penis bones of much bigger bears. Male polar bears, the biggest bears on Earth today, typically weigh 1,100 lbs. (500 kg), but their penis bone averages about 7.3 inches (18.6 cm) long, the researchers say.
The length of the penis bone could reveal details not only about the sexual behavior of Indarctos arctoides, but also the species' ecological habits and mating system.
Based on the size of baculum, the researchers think the bear likely had fewer but longer periods of intercourse than other mammals. A long baculum, the study researchers say, could have served as a physical support during mating, helping to keep the female's reproductive tract open and in an optimal position for fertilization during these sporadic dalliances.
Indarctos arctoides may have also had relatively large individual ranges and possibly a lower population density, giving rise to fewer sexual encounters, the researchers say.
Read more at Discovery News
The mound appears to be 20 to 40 feet (6 to 12 meters) high and 100 feet (30 m) wide, DIG Gwadar Moazzam Jah, a district police officer, told Pakistan's Geo News. It rose out of the sea at a spot located about 350 feet (100 m) from the coast, he said.
The news sparked lively chatter among geologists, who debated whether the hill was a landslide, a fault scarp or even a hoax. A fault scarp marks vertical displacement along a fault, anything from a small step to a huge, steep cliff.
Scientists are still far from consensus, but many think that Pakistan's newest piece of land may be a mud volcano.
Geologist Bob Yeats, an expert on Pakistan's earthquake hazards, said he's waiting until he hears from his colleagues in Pakistan before judging the case. The two most likely possibilities are a landslide or a mud volcano, Yeats told LiveScience's OurAmazingPlanet.
Yeats said Gwadar is several hundred kilometers southwest of the earthquake's epicenter, making it highly unlikely that the new island is a fault scarp.
"(The island) is a long way from where they reported the earthquake. We're looking at two different things," said Yeats, an emeritus professor at Oregon State University.
A mud volcano is a likely possibility because Gwadar's coastline already has several of the gurgling, steamy cones, both onshore and at sea. One suddenly popped up where sea level was 30 to 60 meters (100 to 200 feet) deep on Nov. 26, 2010, creating an island. NASA satellites snapped a photo of the birth.
And in 1945, the magnitude-8.1 Makran temblor triggered the formation of mud volcanoes offshore of Gwadar, according to a study on mud volcanoes in Pakistan published in 2005. A recent study in the journal Nature Geoscience also suggests the 1945 earthquake released tons of methane from the seafloor.
Mud volcanoes appear when sediments like silt and clay become pressurized by hot gas trapped underground. A subduction zone beneath Pakistan supplies the tectonic activity that heats and holds the gas. The Arabian and Eurasian tectonic plates collide offshore of Pakistan, forming a subduction zone, but today's earthquake was onshore and mostly strike-slip — each side of the fault moved horizontally.
Mud volcanoes burble up during earthquakes because the shaking releases mud and water that are trapped beneath barriers in seafloor sediments.
"For example, a clay or shale layer can be impermeable, but if fractured during an earthquake, could release mud and water that was under pressure below the layer. Or a water-rich clay layer could undergo liquefaction that would be released along fractures in the sediments," explained James Hein, a senior scientist with the U.S. Geological Survey in Santa Cruz, Calif. "Some think the island was there before the earthquake, and that would be very easy to check by looking at satellite photos of that area taken the week prior," he said.
But Geologist Dave Petley, a landslide expert, thinks the island's low, arcuate (or bow) shape — as seen in the few pictures released so far — suggests a rotational landslide, rather than a conical mud volcano. A rotational landslide moves along a rupture surface that is curved or concave, like the inside of a spoon.
At this point it is still too early. "It is really very strange, and the pictures are just too indistinct to be able to tell," said Petley, a professor at Durham University in the United Kingdom.
The Arabian Sea isn't the only spot on Earth to spout mud and gas when jiggled by earthquakes. In Japan, the town of Niikappu on the island of Hokkaido sports mud volcanoes that erupt after earthquakes, reports a study published in 1997 in the Journal of the Geological Society of Japan.
The world's most notorious mud volcano, Indonesia's Lusi, destroyed a town in 2006. It may have been caused by an earthquake or by drilling operations nearby.
Read more at Discovery News
The archipelago – named after an Austrian emperor — is among the last true frontiers. Even Google maps can’t zoom in close. The ice-covered islands resemble a white smattering of freckles near the Norwegian island of Svalbard below the North Pole. Fjords and sounds surround the islands, with water depths exceeding 250 meters. The waters are covered in sea ice for 9 months a year. More than 85 percent of the islands are made up of glaciers. A forbidding place, to be sure.
It is a remoteness that men (and a few women) attempted to conquer in the early days of Arctic exploration. Franz Josef Land was officially discovered in 1873, and became a base for a number of expeditions.
The British explorer Frederick George Johnson traveled to Franz Josef Land beginning in 1894 and arrived on the Northbrook Island, the southernmost of the archipelago. He settled at so-called Camp Flora, with the goal of exploring the archipelago and collecting rocks and fossils. His collections revealed to the British Geological Society that the islands were of volcanic origin (as opposed to continental).
In 1896, Johnson suddenly saw a man not of his party on the island: “a tall man, wearing a soft felt hat, loosely made, voluminous clothes and long shaggy hair and beard, all reeking with black grease.”
They had made it farther north than any explorer had in their day, before weather conditions forced a retreat. The men walked for months, fending off polar bears and walruses, and not knowing exactly where they were, before reaching Northbrook Island.
For his part, Nansen, not having heard a human voice for three years, felt his heart beat and blood rush to his brain, as he describes it in his book.
They soon recognized each other and Nansen and Johansen were able to secure passage home with Johnson.
So, Northbrook Island occupies an important place in annals of Arctic exploration.
In 2006, Arctic explorers suggested that Northbrook had split into two, after they found the isthmus connecting its eastern and western halves eroded into the sea.
Read more at Discovery News
The Virginia impact site, called the Chesapeake Bay Crater, is the largest known impact site in the United States and the sixth largest in the world, said Gerald Johnson, professor emeritus of geology at the College of William and Mary in Virginia. Despite its size, clues about the crater weren't found until 1983, when a layer of fused glass beads indicating an impact were recovered as part of a core sample. The site itself wasn't found until nearly a decade later.
The comet or asteroid that caused the impact, and likely measured 5 to 8 miles (8 to 13 kilometers) in diameter, hurtled through the air toward the area that is now Washington, D.C., when it fell. The impact crated a massive wave 1,500 feet (457 meters) high, researchers said.
Though the impactor left a crater about 52 miles across and 1.2 miles deep (84 km across and 1.9 km deep), the object itself vaporized, Johnson explained.
"I'm just sad we can't have a piece of it," Johnson said in a statement.
But the effects of the asteroid impact can still be seen today, most notably in the bay itself. Until 18,000 years ago, the bay region was dry. A giant ice sheet then covered North America, and when it began melting 10,000 years ago, valleys flooded, including the depression formed by the crater.
The ancient impact still affects the region today, in the form of land subsidence, river diversion, disruption of coastal aquifers and ground instability.
Last February, an meteor explosion over the Russian city of Chelyabinsk confirmed that the Chesapeake Bay impactor wasn't the only space rock out there aimed at Earth. Though the Chelyabinsk asteroid was only about 56 feet (17 m) in diameter, it injured more than 1,000 people and caused millions of dollars in structural damage.
"That asteroid still had a major effect on the ground, and there are potentially millions of them," Dan Mazanek, a near-Earth object (NEO) expert at NASA's Langley Research Center in Virginia, said in the statement. "Another meteor of similar size to that would be the next likely event."
Every day, small objects pass near Earth or burn up in the planet's atmosphere. Objects about 50 miles (80 km) across pass within a few lunar distances on a monthly or annual basis without being drawn in by the planet's gravity.
"The frequency is always a question," Mazanek said. "We know that the larger objects are less frequent, but they have more devastating effects."
According to models, scientists have discovered only about 10 percent of the objects larger than 328 feet (100 m), leaving many potentially threatening asteroids that pose a threat to the Earth still unknown.
Both telescope and radar are instrumental in searching for incoming objects. NASA's Near-Earth Object Program is one of the groups watching for potentially dangerous incoming objects. Mazanek said the program has been responsible for about 99 percent of all NEO discoveries since 1998.
Read more at Discovery News
Sep 24, 2013
The news is like a page out of Disney, as these monkeys are small (they weigh just over 1 pound), intelligent and secretive, very cute and fluffy, and have distinctive hairdos. One would imagine that — if any animal whispers — it would have to be them.
Researchers Rachel Morrison and Diana Reiss of The City University of New York made the discovery after recording cotton-top tamarins housed at New York City’s Central Park Zoo. The findings are published in the latest issue of the journal Zoo Biology.
“We exposed a family of captive cotton-top tamarins to a supervisor who previously elicited a strong mobbing response,” they wrote. “Simultaneous audio–video recordings documented the animals’ behavioral and vocal responses in the supervisor’s presence and absence.”
Initially, these very low amplitude vocalizations eluded the researchers’ detection. Careful analysis of the calls, when amplified, showed that the tamarins were whispering to each other.
You can listen to a bunch of different cotton-top tamarin calls at this page.
“Consistent with whisper-like behavior, the amplitude of the tamarins’ vocalizations was significantly reduced only in the presence of the supervisor,” Morrison and Reiss report.
It appears the monkeys were not happy to see this particular supervisor. They may have felt threatened by that individual’s presence and kept their voices down.
We don’t know what they were whispering, but it was probably something like, “Look over there. Be on your guard.” Most animals have alarm calls that communicate things like that, and can even be very specific, mentioning the type of threat, location and more.
Read more at Discovery News
The sika deer (Cervus nippon) was found dead in December 2011 by a researcher tending to the camera trap, which was being used to monitor the habits and movements of tigers in Lazovsky State Nature Reserve in Russia's Far East.
Conservationist Linda Kerley, of the Zoological Society of London (ZSL), recalled that something felt immediately wrong as she approached the carcass.
"There were no large carnivore tracks in the snow, and it looked like the deer had been running and then just stopped and died," Kerley, who runs the ZSL's camera trap project, said in a statement. "It was only after we got back to camp that I checked the images from the camera and pieced everything together. I couldn't believe what I was seeing."
The camera trap footage only captured two seconds of the attack in three photos, but it showed quite clearly an adult golden eagle (Aquila chrysaetos) clinging to the young deer's back.
An adult golden eagle can weigh more than 12 lbs. (5.4 kilograms) and have a wingspan of about 7.5 feet (2.3 meters). Though they do not regularly prey on deer, the raptors are known for ambitious attacks on large animals, the researchers said. The birds, however, have not been known to attack people, despite what the "golden eagle" hoax video would have viewers believe.
"The scientific literature is full of references to golden eagle attacks on different animals from around the world, from things as small as rabbits — their regular prey — to coyote and deer, and even one record in 2004 of an eagle taking a brown bear cub," Jonathan Slaght, of the Wildlife Conservation Society, said in a statement. (ZSL and WCS have been partnering on tiger monitoring in the region.)
"In this case I think Linda just got really lucky and was able to document a very rare, opportunistic predation event," Slaght added.
Read more at Discovery News
The preserved parasites discovered in the mummified young dog's right ear and coat include the common brown tick and louse fly — tiny nuisances that may have carried diseases leading to the puppy's early demise. French archaeologists found the infested dog mummy while studying hundreds of mummified dogs at the excavation site of El Deir in Egypt, during expeditions in 2010 and 2011.
"Although the presence of parasites, as well as ectoparasite-borne diseases, in ancient times was already suspected from the writings of the major Greek and Latin scholars, these facts were not archaeologically proven until now," said Jean-Bernard Huchet, an archaeoentomologist at the National Museum of Natural History in Paris.
Mentions of dog pests appear in the writings of ancient Greeks and Romans such as Homer, Aristotle and Pliny the Elder, and a painting of a hyenalike animal in an ancient Egyptian tomb dated to the 15th century B.C. shows what is likely the oldest known depiction of ticks. But evidence of ticks, flies and other ectoparasites that infest the outside of the body has been scarce in the archaeological record -- until now. (The only other known archaeological evidence of ticks comes from fossilized human feces in Arizona.)
Counting the bloodsuckers
The infested dog mummy was discovered in one of many tombs surrounding a Roman fortress built in the late third century A.D. Most of the main tombs were built during a period dating from the fourth century B.C. to the fourth century A.D. -- a treasure trove for archaeologists, despite the condition of many of the mummies. The French team detailed its findings in the August online issue of the International Journal of Paleopathology.
Huchet and his colleagues, led by Françoise Dunand and Roger Lichtenberg of the University of Strasbourg in France, found the remains of the parasite-ridden pup among more than 400 dog mummies.
"Among the hundreds of dog mummies studied, of them were either skeletonized or still wrapped with bandages," Huchet told LiveScience. "Moreover, most of the dog remains were seriously damaged by looters."
The infested young pup stood out with 61 preserved brown dog ticks still clinging to its coat and nestled in its left ear. Such ticks have spread worldwide by feeding on domesticated dogs. They can also infect their hosts with a variety of potentially fatal diseases.
Archaeologists also discovered a single bloodsucking louse fly clinging firmly to the dog's coat. But the team hypothesizes a tick-borne disease such as canine babesiosis -- a condition that destroys red blood cells -- likely caused the young dog's premature death.
Origins of dog mummies
Hardened skin remains of maturing fly larvae suggested the dying or dead dog had attracted two species of carrion flies before Egyptian handlers mummified the corpse.
Ancient Egyptians commonly mummified animals such as dogs, cats and long-legged wading birds called ibis. The dog mummies from the El Deir site almost certainly represented offerings to a jackal-headed Egyptian god such as Anubis or Wepwawet.
"Several reasons have led Egyptians to mummify animals: to eat in the afterlife, to be with pets, etc.," said Cecile Callou, an archaeozoologist at the National Museum of Natural History in Paris. "But above all, animals were considered as living incarnations of divine principles and, therefore, associated with deities."
But many questions remain about the mummified dogs of El Deir. Researchers still want to know where the dogs came from, whether they were domestic dogs, whether they had owners and how they died. Callou pointed out that the ancient Egyptians had cat farms where cats were bred to be sacrificed and mummified -- could the same have been true for dogs?
Digging deeper into history
The French archaeologists hope to find answers to a different set of questions by searching for more preserved ticks and flies among the mummified dogs of El Deir. Such archaeological evidence could show how diseases originated throughout history, provide clues about the geographical spread of parasites, and reveal more about the relationship between parasites and both human and animal evolution.
Read more at Discovery News
But sometimes there’s not enough material to get to that point. The protostar, for whatever reason, doesn’t get massive enough to begin the hydrogen fusing process inside it. It’s collected all the dust and gas that was available but it still not enough to ignite. Falling short of full-blown stardom, it’s doomed to drift through the galaxy as a cool, dark brown dwarf… and there’s one right in our stellar neighborhood.
The VVV survey (which stands for VISTA Variables in the Via Lactea, i.e., “Milky Way”) searches the area of the sky near the central bulge of our galaxy in near-infrared wavelengths. It’s in these heat-generated emissions that hidden brown dwarfs are most easily found, as they are otherwise optically very dim.
Despite the name, brown dwarfs aren’t actually brown. But VVV BD001 is even less so (well, kinda sorta) — it’s one of a curious breed known as “unusually blue brown dwarfs.” These emit shorter-wavelength infrared light than most brown dwarfs for reasons not entirely understood (but then, wouldn’t necessarily look blue to our eyes either.) Regardless, it makes VVV BD001 an extra-special find! (Read more on this here.)
Read more at Discovery News
Sep 23, 2013
“We called this ‘Spiderbag’,” said Thomas Scheibel, a protein-chemist-turned-engineer, and coauthor of a study describing the capsules published in Advanced Functional Materials. The tiny spheres, produced by Scheibel and his colleagues at the University of Bayreuth, are about as strong as glass — comparable to the ornamental globes that hang on Christmas trees, “just a few sizes smaller,” Scheibel says.
At once both tough and malleable, the silky containers can sheath proteins that would normally want to react with many things around them. The silk stops the enzymes from unfolding or becoming inactive before they’re needed. Soon, the team says, these capsules will be ready for use in medical diagnostics. Though tiny, the spheres are too large to be injectable. Instead, though he won’t go into details, Scheibel says the capsules could be used as a super-sensitive array capable of detecting performance-enhancing substances in athletes, for example.
“They could be used as an analytical tool, to identify substances in the body, in the blood — like drugs,” Scheibel says.
So, if you’ve included an enzyme in that original watery solution, it’s now locked up and waiting for the right time to step outside. The team tested the system with enzymes and proteins normally used in lab work, such as beta-galactosidase and serum albumins, but Scheibel says it could be used with just about anything that doesn’t react with spider silk itself.
Modifying the size of the initial droplets allows scientists to make the capsules larger or smaller, in effect customizing the silky spheres for various applications. “You could also do it the other way around, too, and make oil droplets in water,” Scheibel said. Such a reversal would be useful for systems needing oil-friendly enzymes.
“This concept of utilizing silk as a matrix to house or contain enzymes or other bioactive molecules is a fantastic direction to go in,” said David Kaplan, a biopolymer engineer at Tufts University who is working on something similar using silkworm silk. “It offers tremendous control over what you want those containers to do.”
Others would like a bit more evidence that silky capsules offer something that other engineered molecules don’t.
“I don’t see the obvious advantages over other synthetic polymers yet,” said Randy Lewis, a molecular biologist at Utah State University. Lewis’ group recently received funding from the U.S. Navy for a project involving spider silk adhesives – they’re hoping to make something resembling one-sided Velcro that will easily stick to anything, even wet or slimy surfaces.
It’s no surprise that different research groups are examining the potential offered by synthetic silks. Spider silk itself has earned a reputation as a wonder-material: As tough as steel, biocompatible, environmentally friendly, stretchy and antiseptic, the substance can seemingly do pretty much anything you want it to.
“For hundreds of years, there’s been a myth that spider silk is the best performing fiber. Which is actually true,” Scheibel says. “Mechanically, it outcompetes everything.”
It’s also kind of smart. “You can design it, and under the right conditions, it knows how to find its corresponding polymer partner and organize itself into a structure that becomes very robust and useful,” Kaplan said. And when you’re done with it, “You could eat it. Or put it in the water or soil — it’s not going to hurt anything,” he says.
But making enough spider silk to use commercially has been a challenge. Spiders, unlike other critters amenable to farming, tend to eat one another when sharing captive spaces. They also don’t produce much silk – it took a million spiders and four years to create a single, gleaming golden cloth.
So, scientists are coaxing other organisms to produce the spider silk. So far, goats, silkworms, E.coli, and alfalfa (yup), have made the strong, sticky substance – or at least, the proteins that go into making the actual fiber. Inside a spider, silk proteins live in a soupy, unstructured jumble that remains goopy until the spider pulls a trigger that snaps the proteins into steely, fiber form. Perhaps not surprisingly, different labs are experimenting with ways to replicate this part of the silk-crafting arachnid experience; so far, methods like pulling the proteins through a fine syringe, and electrospinning (where an electrical charge pulls fibers from a solution), have been the most used. Silky coatings, capsules, gels and foams form readily when other triggers, like salts, are pulled.
Scheibel’s team uses little bacterial factories – colonies of E.coli – to make silk. These bacteria carry the silk protein genes from orb-weaving spiders such as Nephila clavipes and Araneus diadematus. Normally, though, E.coli would look at the genetic sequence for spider proteins and hit the road; it’s tough for a single-celled organism to produce massive, repetitive proteins like the silk’s building blocks. So, Scheibel and his team removed some of the repetitive elements and translated the code into something the bacteria could understand – then let them get to work.
Read more at Wired Science
Buried under soil for hundreds of years, the goddess of love and beauty has some chipping on her nose and face. Researchers think her presence could shed light on the extent of the Roman Empire's wide cultural influence at the time of its peak.
Archaeologists found the sculpture while working at a site called Antiochia ad Cragum (Antioch on the cliffs), on the Mediterranean coast. The researchers believe the region, which is dotted with hidden inlets and coves, would have been a haven for Cilician pirates — the same group who kidnapped Julius Caesar and held him for ransom around 75 B.C.
But the pirates' reign ended when the Roman occupation of the area expanded. The city was officially established around the time of Emperor Nero and flourished during the height of the Roman Empire, researchers say.
The excavators had been looking for more parts of the largest Roman mosaic ever found in Turkey: a 1,600-square-foot (150 square meters) marble floor elaborately decorated with geometric designs, adorning a plaza outside a Roman bath. During fresh excavations this past summer, they found the statue head lying face-down. The researchers think the marble head was likely long separated from its body; traces of lime kilns have been found near the site, suggesting many statues and hunks of stone would have been burned to be reused in concrete.
Past scholars have argued that southern Turkey's culture was too insular to be greatly impacted by Rome's reach and that it was a peripheral part of the empire. But the presence of an Aphrodite sculpture suggests Greek and Roman influence had become mainstream in far-flung cities like Antiochia ad Cragum in the first and second centuries A.D., the excavation's director Michael Hoff, an art historian at the University of Nebraska-Lincoln, said in a statement.
Hoff said Aphrodite's head is the first fragment of a monumental statue they have found at Antiochia ad Cragum over eight years of digging.
"We have niches where statues once were. We just didn't have any statues," Hoff said in a statement. "Finally, we have the head of a statue. It suggests something of how mainstream these people were who were living here, how much they were a part of the overall Greek and Roman traditions."
Read more at Discovery News
"There's a crazy contrast between these delicate, glass-shelled organisms and one of the most powerful eruptions in Earth's history," said lead study author Alexa Van Eaton, a postdoctoral scholar at both the Cascades Volcano Observatory in Washington and Arizona State University.
The diatoms were launched by the Taupo super-eruption on New Zealand's North Island 25,000 years ago. More than 600 million cubic meters (20 billion cubic feet) of diatoms from a lake flew into the air, Van Eaton reported Sept. 6 in the journal Geology. Lumped together, the microscopic cells speckled throughout Taupo's ash layers would make a pile as big as Hawaii's famed Diamond Head volcanic cone.
Some diatoms drifted as far as the Chatham Islands, 525 miles (850 kilometers) east of New Zealand. "They just hitched a ride," Van Eaton said. The pristine shells in the Chatham Island ash suggest diatoms could infect new niches by coasting on atmospheric currents.
"If they made it there alive, this is one way microorganisms can travel and meet each other," Van Eaton told LiveScience's OurAmazingPlanet. "We know that ash from smaller events easily travels around the world."
Diatoms, a golden brown algae, rule Earth's waterways. From Antarctica's glacial lakes to acidic hot springs to unkempt home aquariums, diatoms are everywhere. It's a good thing. The tiny creatures pump out up to 50 percent of the planet's oxygen, said Edward Theriot, a diatom expert and evolutionary biologist at the University of Texas at Austin, who was not involved in the study.
The algae look like little petri dishes or footballs, depending on the species, and spend most of their lives drifting on currents. How diatoms manage to colonize new homes remains a mystery: They can't swim.
Yet diatoms get around. When Wyoming's Yellowstone Lake emerged from its mile-thick ice cover 14,000 years ago, diatoms quickly arrived, Theriot said. "They had to be blown in by some mechanism or carried in by water birds," he added.
Diatoms particularly love volcanic lakes, because they are the only creatures that build shells of glass. (Glass sponges, for instance, produce a skeleton of glass spicules — tiny spike-like structures — but not a hard shell.) Silica-rich magma often causes the volcanic explosions that leave behind lake-filled craters, and silica is the key ingredient in diatom shells. Yellowstone Lake, which sits in a caldera created by a super-eruption, contains so many diatoms that the lake sediments are mostly shells (85 percent by weight), Theriot said.
Now scientists know what happens to diatoms when a massive volcano like Yellowstone blasts through a big lake.
The Taupo Volcano super-eruption slammed through a deep lake that filled a rift valley, similar to the elongated lakes in East Africa. The combination of water and ash created a hellish dirty thunderstorm, with towering clouds and roaring winds. The detonation flung ash and algae upward at more than 250 mph (400 km/h), Van Eaton said. Volcanic hail (called accretionary lapilli) pelted the landscape for miles.
Van Eaton discovered the diatoms while examining the volcanic hail with a scanning electron microscope.
"The first time I ever saw them I was looking at these volcanic ash aggregates and, bam, these gorgeous little symmetrical shells were there," she said. "Their shells are immaculately preserved."
Van Eaton soon determined that one of the three diatom species entombed in the ash only lives on the North Island of New Zealand. This meant she could track the 25,000-year-old ash layers around the South Pacific with a unique biologic marker. The unique North Island diatoms turned up in a few inches of ash on the Chatham Islands. The diatoms' trip to the Chatham Islands took longer than it looks on a map. The prevailing winds blew west at the time, so the shells circled the Southern Hemisphere before landing on the islands, Van Eaton and her colleagues deduce.
Some of the diatoms even kept their color, both in ash close to the volcano and at the Chatham Islands. The color suggests they weren't cooked to extreme temperatures in the volcanic eruption, Van Eaton said.
Read more at Discovery News
The leading theory of how the moon formed holds that it was created when a mysterious planet — one the size of Mars or larger — slammed into Earth about 4.56 billion years ago, just after the solar system came together. But new analyses of lunar rocks suggest that the moon, which likely coalesced from the debris blasted into space by this monster impact, is actually between 4.4 billion and 4.45 billion years old.
The finding, which would make the moon 100 million years younger than previously thought, could reshape scientists' understanding of the early Earth as well as its natural satellite, researchers said.
"There are several important implications of this late moon formation that have not yet been worked out," Richard Carlson, of the Carnegie Institution for Science in Washington, D.C., said in a statement.
"For example, if the Earth was already differentiated prior to the giant impact, would the impact have blown off the primordial atmosphere that formed from this earlier epoch of Earth history?" added Carlson, who is presenting the new results Monday (Sept. 23) in London at a meeting organized by the Royal Society called "Origin of the Moon."
Scientists know the solar system's age (4.568 billion years) quite well. And they can pin down the formation times of relatively small bodies such as asteroids precisely, too, by noting when these objects underwent extensive melting — a consequence, in part, of the heat generated by the collision and fusion of these objects' building-block "planetesimals."
For example, analysis of meteorites that came from the asteroid Vesta and eventually rained down on Earth reveals that the 330-mile-wide (530 kilometers) space rock is 4.565 billion years old. Vesta cooled relatively quickly and is too small to have retained enough internal heat to drive further melting or volcanism, Carlson explained.
But it's tougher to nail down the age of larger solar-system bodies, he said.
"Ask the same question of the Earth or moon, and you don't get a very precise answer," Carlson said. "Earth likely took longer to grow to full size compared to a small asteroid like Vesta, and every step in its growth tends to erase, or at least cloud, the memory of earlier events."
Scientists keep getting better and better estimates, however, as they refine their techniques and technology improves. And those estimates are pushing the moon's formation date farther forward in time.
The moon is thought to have harbored a global ocean of molten rock shortly after its dramatic formation. Currently, the most precisely determined age for the lunar rocks that arose from that ocean is 4.360 billion years, the researchers said.
Read more at Discovery News
Sep 22, 2013
|Scanning electron microscope images are of CNT forests with low and high density.|
Now a team from Cambridge University in England has devised a simple technique to increase the density of nanotube forests grown on conductive supports about five times over previous methods. The high density nanotubes might one day replace some metal electronic components, leading to faster devices. The researchers report their finding in the journal Applied Physics Letters, which is produced by AIP Publishing.
"The high density aspect is often overlooked in many carbon nanotube growth processes, and is an unusual feature of our approach," says John Robertson, a professor in the electronic devices and materials group in the department of engineering at Cambridge. High-density forests are necessary for certain applications of carbon nanotubes, like electronic interconnects and thermal interface materials, he says.
Robertson and his colleagues grew carbon nanotubes on a conductive copper surface that was coated with co-catalysts cobalt and molybdenum. In a novel approach, the researchers grew at lower temperature than is typical which is applicable in the semiconductor industry. When the interaction of metals was analyzed by X-ray photoelectron spectroscopy, it revealed the creation of a more supportive substrate for the forests to root in. The subsequent nanotube growth exhibited the highest mass density reported so far.
Read more at Science Daily
The project team at NASA's Jet Propulsion Laboratory in Pasadena, Calif., has reluctantly pronounced the mission at an end after being unable to communicate with the spacecraft for over a month. The last communication with the probe was Aug. 8. Deep Impact was history's most traveled comet research mission, going about 4.7 billion miles (7.58 billion kilometers).
"Deep Impact has been a fantastic, long-lasting spacecraft that has produced far more data than we had planned," said Mike A'Hearn, the Deep Impact principal investigator at the University of Maryland in College Park. "It has revolutionized our understanding of comets and their activity."
Deep Impact successfully completed its original bold mission of six months in 2005 to investigate both the surface and interior composition of a comet, and a subsequent extended mission of another comet flyby and observations of planets around other stars that lasted from July 2007 to December 2010. Since then, the spacecraft has been continually used as a space-borne planetary observatory to capture images and other scientific data on several targets of opportunity with its telescopes and instrumentation.
Launched in January 2005, the spacecraft first traveled about 268 million miles (431 million kilometers) to the vicinity of comet Tempel 1. On July 3, 2005, the spacecraft deployed an impactor into the path of comet to essentially be run over by its nucleus on July 4. This caused material from below the comet's surface to be blasted out into space where it could be examined by the telescopes and instrumentation of the flyby spacecraft. Sixteen days after that comet encounter, the Deep Impact team placed the spacecraft on a trajectory to fly back past Earth in late December 2007 to put it on course to encounter another comet, Hartley 2 in November 2010.
"Six months after launch, this spacecraft had already completed its planned mission to study comet Tempel 1," said Tim Larson, project manager of Deep Impact at JPL. "But the science team kept finding interesting things to do, and through the ingenuity of our mission team and navigators and support of NASA's Discovery Program, this spacecraft kept it up for more than eight years, producing amazing results all along the way."
The spacecraft's extended mission culminated in the successful flyby of comet Hartley 2 on Nov. 4, 2010. Along the way, it also observed six different stars to confirm the motion of planets orbiting them, and took images and data of Earth, the moon and Mars. These data helped to confirm the existence of water on the moon, and attempted to confirm the methane signature in the atmosphere of Mars. One sequence of images is a breathtaking view of the moon transiting across the face of Earth.
In January 2012, Deep Impact performed imaging and accessed the composition of distant comet C/2009 P1 (Garradd). It took images of comet ISON this year and collected early images of ISON in June.
After losing contact with the spacecraft last month, mission controllers spent several weeks trying to uplink commands to reactivate its onboard systems. Although the exact cause of the loss is not known, analysis has uncovered a potential problem with computer time tagging that could have led to loss of control for Deep Impact's orientation. That would then affect the positioning of its radio antennas, making communication difficult, as well as its solar arrays, which would in turn prevent the spacecraft from getting power and allow cold temperatures to ruin onboard equipment, essentially freezing its battery and propulsion systems.
"Despite this unexpected final curtain call, Deep Impact already achieved much more than ever was envisioned," said Lindley Johnson, the Discovery Program Executive at NASA Headquarters, and the Program Executive for the mission since a year before it launched. "Deep Impact has completely overturned what we thought we knew about comets and also provided a treasure trove of additional planetary science that will be the source data of research for years to come."
Read more at Science Daily