Dec 8, 2016

John Glenn, American Hero and NASA Astronaut, Has Died

Former astronaut and U.S. Sen. John Glenn, 95, has died in his home state of Ohio after being hospitalized more than a week.

No further information on Glenn's cause of death was available.

"John Glenn is the last of the original seven American astronauts who truly had the 'right stuff.' On top of paving the way for the rest of us, he was also a first-class gentleman and an unabashed patriot," U.S. Sen. Bill Nelson, a Florida Democrat, said in a statement.

Glenn's 4-hour, 55-minute spaceflight on Feb. 20, 1962 marked a turning point in the tense race with the Soviet Union to develop missiles capable of precision strikes across the continents. Space was where the technology was showcased and until Glenn's flight, America was behind.

The Soviets had launched the first satellite, Sputnik, on Oct. 4, 1957, the first animal (a dog named Laika) on Nov. 3, 1957, and then the first person, cosmonaut Yuri Gagarin, on April 12, 1961.

"Sputnik was totally unexpected," historian Alan Marcus, now with Mississippi State University, said in an interview marking the 40th anniversary of Glenn's flight.

"Here were what we thought were these backward Russians putting up a satellite. Then came the Cuban missile crisis and we had this incredible tension between the Soviet Union and us. All these problems made Glenn's flight rewarding, but it was not the end-all be-all … It was a step on the way to winning the Cold War," he said.

Before Glenn strapped himself inside the Friendship 7 capsule and blasted off, two of his Mercury Seven brothers, Alan Shepard and Gus Grissom, had made short suborbital spaceflights. Wary of the Soviets and despite just 31 minutes of total U.S spaceflight experience, President John F. Kennedy issued a brash call for astronauts to land on the moon before the end of the decade.

Against that backdrop came Glenn, a straight-laced Marine Corps pilot from Ohio who had flown 59 combat missions during World War II and 100 missions in Korea before being selected as one of NASA's first astronauts.

In addition to Shepard, Grissom and Glenn, the Mercury Seven included Scott Carpenter, Gordon Cooper, Wally Schirra and Deke Slayton. Glenn, the eldest of the group, was the last surviving member.

Glenn made three orbits around Earth, reaching a maximum altitude of about 162 miles and a speed of about 17,500 mph before splashing down 800 miles southeast of Cape Canaveral, Florida, near Grand Turk Island. He returned home an instant hero, honored with a ticker-tape parade in New York City and a Congressional Medal of Honor from President Kennedy.

Read more at Discovery News

A Dinosaur's Bloody Feathered Tail Has Been Found Preserved in Amber

When paleontologist Lida Xing of the China University of Geosciences in Beijing visited an amber market two years ago in Myitkyina, Myanmar, one piece immediately caught the researcher's eye. Xing placed a flashlight under the amber chunk and noticed many slender feathers arranged in an elongated structure. Suspecting that it was an important object, Xing suggested that the Dexu Institute of Paleontology buy the amber.

When Xing and colleagues later CT scanned the amber and analyzed its chemistry, even they were surprised by what they found: a dinosaur tail, residue of dinosaur blood and insects that likely scavenged on the deceased dino, which died about 99 million years ago. The discovery is reported in the journal Current Biology.

Close-up of the 99-million-year-old dinosaur tail in amber. Scavenging insects can also be seen.
"Per pound, it is the most incredible fossil I have ever seen, and it is as close to Jurassic Park as we have ever gotten," co-author Scott Person of the University of Alberta told Seeker.

Co-author Ryan McKellar of the Royal Saskatchewan Museum added, "This is the first time that skeletal material from a dinosaur has been found in amber. Previous finds in amber have included isolated feathers that may have belonged to dinosaurs, but without an identifiable part of the body included, their source has remained open to debate."

The researchers believe that a juvenile carnivorous dinosaur belonging to the Maniraptora clade (dinos closely related to birds) could have become trapped in tree resin and died, or passed on for other reasons before resin dripped on it and hardened.

Recreation of a maniraptoran dinosaur that could resemble the individual whose tail became trapped in tree resin 99 million years ago.
"There are no struggle marks in the amber, so we cannot know for certain," McKellar told Seeker. "That said, there is milky amber around the tail that suggests at least a little bit of moisture remained in the tail when it was encapsulated. Some of the insects trapped alongside the tail also belong to groups that scavenge."

Persons added, "The little bit of tail comes from a dinosaur probably about the size of a robin. The shape of the tail vertebrae, which we can only see in X-ray images, indicates that the dinosaur was a two-legged carnivore. It may be a hatchling or possibly an extremely small species that's new to science. So little of the skeleton is preserved that we cannot tell."

The researchers could confirm that the tail comes from a dinosaur, and not a prehistoric bird, because of its structure. They explained that the tail is long and flexible, lacking a well-developed central shaft, known as a rachis. Keels of feathers run down each side. The structure of these feathers suggests that the two finest tiers of branching seen in modern feathers, called barbs and barbules, arose before a rachis formed.

"The development of the rachis allows feathers to form long, vaned shapes that are useful for more than just temperature, regulation, or visual signaling," McKellar said. "It provides feathers that are more useful in controlled flight."

Visible traces of pigmentation in the tail's plumage reveal that its upper surface was chestnut brown in color, while its underside was pale or white during the dinosaur's lifetime. The contrast must have been quite striking as the animal moved about.

Illustration showing what the maniraptoran dinosaur might have looked like when alive and hunting for food.
The amber also remarkably contains some of the original iron from dinosaur blood. If the specimen had been found just a few decades ago, there would have been great hope that it could contain DNA, but studies conducted over recent years suggest that remains degrade too quickly when preserved in amber as well as in related materials, such as copal.

The researchers are now eager to see how more finds from Myanmar and surrounding regions might reshape our understanding of plumage and soft tissues in dinosaurs and other prehistoric animals.

Read more at Discovery News

A 17th-Century Child Mummy Just Rewrote the History of Smallpox

An international team of researchers has identified the oldest known sample of the variola virus that causes smallpox in the mummified remains of a 17th-century child.

The findings, published in the journal Current Biology, raise new questions about the history of the pathogen, suggesting that smallpox, once thought to be an ancient disease, may have in fact emerged in rather recent times.

Smallpox remains the only human disease eradicated by vaccination — it was also the first disease to be combated with a vaccine when one was developed in 1796.

However, the history of this pathogen that caused millions of deaths worldwide remains mysterious.

"Scientists don't yet fully comprehend where smallpox came from and when it jumped into humans," said evolutionary geneticist Hendrik Poinar, director of the McMaster Ancient DNA Center and a researcher with Michael G. DeGroote Institute of Infectious Disease Research.

The disease had long been thought to have appeared in human populations thousands of years ago. Some researchers even diagnosed the pharaoh Ramses V with smallpox on the basis of visible pustular rashes and scars.

They may have been wrong, the study suggests.

New clues on the evolutionary history of the devastating viral disease came from the partial mummified remains of a child of undetermined sex. The mummy was found with no coffin or associated artifacts in the crypt of the Dominican Church of the Holy Spirit of Vilnius, Lithuania.

Once scheduled to be buried, the remains are now part of a project created in 2011 by anthropologist Dario Piombino-Mascali to study all the mummies in Lithuania, from the Egyptian mummies in the local museums, to the remains from the Holy Spirit crypt and 20th-century anatomical preparations.

"Those mummies revealed a number of diseases, such as arteriosclerosis, tuberculosis and bone pathologies. But this case has been really surprising," Piombino-Mascali, at the department of anatomy, histology, and anthropology of Vilnius University, told Seeker.

According to the researchers, the child died between the ages of 2 and 4 and in the years between 1643 and 1665, close to the time of several documented European epidemics.

Heavily fragmented DNA was extracted from the mummy's skin so the researchers were able to capture, sequence and reconstruct the complete genome of an ancient strain of variola virus. There was no indication of a live virus in the sample, so the mummy was not infectious.

"We believe this is the oldest smallpox genome sequenced to date," Ana Duggan, a postdoctoral fellow at the McMaster University Ancient DNA Center in Canada, told Seeker.

Duggan and colleagues compared the 17th-century strain to versions of the variola virus genome dating from 1946 up to 1977. The disease was declared eradicated by the World Health Organization in 1980.

"The results showed a very recent common ancestor for all available 20th-century variola strains and our 17th-century strain," Duggan said.

Indeed, the common viral ancestor originated sometime between 1588 and 1645, a date corresponding to a period of exploration, migration and colonization that would have helped the viral dissemination of smallpox around the globe.

Read more at Discovery News

First Animal to Walk on Land Traced to Scotland

The late Stan Wood, a self-taught paleontologist from Scotland, had an unwavering belief that the earliest animals to walk on land did so in his homeland. In 2011, just a year before he died of cancer, Wood discovered fossils of four-legged animals known as tetrapods at an unassuming place called Willie's Hole, located near Chirnside, Scotland.

The remains dated to between 360 and 345 million years ago, which is when most scientists believe vertebrates—animals with backbones—made the transition from sea to land.

A National Museums Scotland-organized excavation team returned to Willie's Hole in 2015 and unearthed evidence supporting Wood's long-held belief. They found the remains of five new fossil species, which date to about 355 million years ago and are thought to be the earliest known four-legged vertebrates to walk on terra firma. The fossils are described in the latest issue of the journal Nature Ecology & Evolution.

(Left) The late Stan Wood in 2010 pointing to Willie's Hole, Scotland. Credit: Jennifer A. Clack (Right) The National Museums Scotland-organised excavation of that site in 2015.
Once on land, tetrapods diverged into two groups: the ancestors of amphibians and the ancestors of reptiles, birds and mammals. This means that in a sense, as mammals, all humans can trace their ancestry back to Scotland.

Co-author Nick Fraser of National Museums Scotland admits the connection is a colossal stretch, but explained that the first literal animal step on land was "a pivotal step in the evolution of life on Earth." Without this moment, "the evolution of birds, crocodiles, pterosaurs, salamanders, dinosaurs, mammals—and, of course, ourselves—and birds could not have occurred."

What led to that important step, which Fraser likens to the "one giant leap for mankind" first step on the moon, appears to have been the aftermath of the late Devonian mass extinction that occurred 358 million years ago. The land masses that now form Scotland were then in very different locations, closer to the equator.

"We think the area was subject to quite a bit of change—low-lying ponds, lagoons and streams were being subjected to intermittent flooding and occasional inundation by the nearby sea," Fraser said, adding that there were also "periods of aridity."

The conditions were clearly demanding, he continued, so "it might well have been this dynamic changing environment that partly drove the transition to land by some of the early tetrapods."

The move happened gradually, such that the still fishy-looking animals had a semi-aquatic lifestyle, which at least involved returning to water to lay eggs, before later tetrapods evolved to become fully terrestrial. Those animals, "fully emancipated from water," as Fraser said, date to 345 million years ago in Scotland.

Artist's impression of the underwater environment of a swamp dating to about 355 million years ago.
This critical time in history has been murky due to a 15-million-year hole in the tetrapod fossil record known as Romer's Gap that extends between 345 and 360 million years ago. Wood's fossils, as well as those of Fraser and his colleagues, help to fill that gap.

Read more at Discovery News

Ancient Space Dust Washes Up in Rooftop Gutters

Through dogged determination, Jon Larsen has become driven to find space particles, which date back to when our sun was a baby, in the urban sediment that collects in the guttering of building rooftops. And, after he convinced a British planetary scientist to study his findings, years of work have finally paid off.

In 2011, Larsen reached out to Matthew Genge, of Imperial College London, with his plan to find dust particles in this seemingly unlikely place. Though distinguishing space particles from the zoo of man-made dust particles in a city environment was considered too difficult, the hurdle didn't deter Larsen.

"It was an amateur scientist, a chap called Jon Larsen who's actually quite a well-known jazz musician in Norway, who got interested in this and started collecting all the debris that ends up in the gutter," Genge told Seeker. After going through the debris found in the roof guttering from buildings in Oslo, Paris and Berlin, Larsen would send photos of interesting particles he'd find to Genge and, despite his pessimism that Larsen would ever uncover this unlikely quarry, he eventually struck gold.

Now, with Genge's assistance, the pair have identified hundreds of particles that fell from space and have origins dating back to the birth of the solar system. Larsen documents his micrometeorite discoveries as part of Project Stardust.

"Imagine somebody who has been sending you pictures every other week of something, and every time you look at them, you're like 'no, no, no, that's not it' and then after 5 years they send you a picture and it actually is the thing that you're looking for... that was the moment I went 'oh, my God! I should pay more attention to this guy!'" Genge added.

"He's put in so much work. He went through 300 kilograms [660 lb] of sediment from gutters. That's pretty incredible."

As described in research published in the journal Geology, the duo identified 500 particles of dust that originate from asteroids and comets. But finding these cosmic artifacts in the dirt was just the beginning; their research has revealed some profound science about the space dust that is falling onto our heads right at this moment and could add another layer to our understanding about the building blocks of planets.

Our solar system is filled with dust from collisions between asteroids and venting from comets. The most visible sign of this dust encountering Earth are the meteor showers that light up the upper atmosphere as Earth orbits though one of the many dusty trails left behind these interplanetary vagabonds. However, the tiny particles that rain through the atmosphere as "shooting stars" burn up completely, leaving only a bright flash in their wake. Their journey comes to an abrupt end as a blaze of super-heated glory.

"These particles [in gutter sediment] are almost definitely not coming from meteor showers as that dust comes in too fast — it comes in at maybe 30 kilometers per second [67,000 miles per hour] — and it completely evaporates in the Earth's atmosphere," said Genges.

The gutter particles are thought to enter the atmosphere at a speed of around 12 kilometers per second (27,000 miles per hour) where atmospheric heating does inevitably heat up the particles, but the dust survives the fall. Judging by their size of around 0.3 millimeters, these are likely the fastest dust particles to survive the hot atmospheric entry, noted Genges. Through analysis of the 500 specimens, the researchers found there to be a mix of particles that originate from asteroids and others that originate from comets.

"We have found dust particles that we think come from comets and they are subtly different from those that come from asteroids ... they are carbon rich. Whereas the ones from asteroids look similar to the material from meteorites, that are also from asteroids," he added.

Separating the cosmic particles from plain old gutter dirt is no easy task, but the researchers used an important trait found in these space particles to their advantage — they contain minerals that make them magnetic. So, by magnetically separating the dirt under the microscope, these particles could be found.

"These [particles] are very similar to the cosmic dust from deep sea sediments," said Genges. "The main difference is that these are very young. Because they've been largely collected from roofs on commercial buildings, those buildings have their gutters cleaned at least every 3-5 years, so we know these [particles] have landed on Earth at least in the last 5 years. Whereas the particles found on the seabed are up to 50,000 years old. These are a sample of what's landing on Earth, practically today."

As this dust has fallen to Earth within the last 5 years, the researchers could even deduce how the solar system dust falling on Earth has changed over the last million years. The dust found in city gutters contains fewer crystals than the dust that has been found in million-year-old ice Antarctica, for example, but the particles are remarkably similar to cosmic dust that fell onto Earth in medieval times.

According to an Imperial College London press release, the researchers think that the changes in dust particle structure could be down to very small orbital changes in the solar system's planets over millions of years. The slight gravitational disturbances likely change the trajectory of the interplanetary dust, causing it to hit the Earth's atmosphere at different speeds and angles. These slight changes can therefore influence how much heating is caused by atmospheric entry which, in turn, influences the size of the particles that make it to the ground and influence the shape of the crystals inside the microscopic grains.

Read more at Discovery News

Dec 7, 2016

Scientists shed new light on how the brain processes, maintains what we don't see

A team of scientists has mapped out how our brains process visuals we don’t even know we’ve seen, indicating that the neuronal encoding and maintenance of subliminal images is more substantial than previously thought.
A team of scientists has mapped out how our brains process visuals we don't even know we've seen, indicating that the neuronal encoding and maintenance of subliminal images is more substantial than previously thought.

"Our results indicate that what is 'invisible' to the naked eye can, in fact, be encoded and briefly stored by our brain," observes Jean-Rémi King, a postdoctoral fellow in NYU's Department of Psychology and one of the researchers.

The co-authors of study, which appears in the journal Neuron, also include Niccolo Pescetelli, a doctoral student at the University of Oxford, and Stanislas Dehaene, a professor at Collège de France.

In their study, human subjects viewed a series of quickly flashed images, and reported which ones they saw and which they could not see, while their brain activity was monitored using magnetoencephalography (MEG) -- a non-invasive neuroimaging technique which makes, at every millisecond, multiple measurements of the tiny magnetic fields generated by the neuronal activity. Critically, the authors developed machine learning algorithms to decode the content of these images directly from these large and complex neuroimaging data.

These new algorithms allowed the authors to confirm a series of theoretical predictions. In particular, they reveal a striking dissociation between the dynamics of "objective" (i.e. the visual information presented to the eyes) and "subjective" neural representations (i.e. what subjects report having seen). However, and contrarily to theoretical predictions, the authors also showed that invisible images can be partially maintained within high-level regions of the brain.

"Undoubtedly, these results suggest that our current understanding of the neural mechanisms of conscious perception may need to be revised," notes King, who also holds an appointment at the Frankfurt Institute for Advanced Studies (FIAS). "However, beyond our empirical findings, this study demonstrates that machine learning tools can be remarkably powerful at decoding neuronal activity from MEG recordings -- a preview of what we can uncover about the workings of the brain.

From Science Daily

Overwhelming evidence of malaria's existence 2,000 years ago

An analysis of 2,000-year-old human remains from several regions across the Italian peninsula has confirmed the presence of malaria during the Roman Empire, addressing a longstanding debate about its pervasiveness in this ancient civilization.

The answer is in mitochondrial genomic evidence of malaria, coaxed from the teeth of bodies buried in three Italian cemeteries, dating back to the Imperial period of the 1st to 3rd centuries Common Era.

The genomic data is important, say researchers, because it serves as a key reference point for when and where the parasite existed in humans, and provides more information about the evolution of human disease.

"Malaria was likely a significant historical pathogen that caused widespread death in ancient Rome," says evolutionary geneticist Hendrik Poinar, director of McMaster's Ancient DNA Centre where the work was conducted.

A serious and sometimes fatal infectious disease that is spread by infected mosquitoes, malaria and its parasite Plasmodium falciparum, is responsible for nearly 450,000 deaths every year, the majority of them children under the age of five.

"There is extensive written evidence describing fevers that sound like malaria in ancient Greece and Rome, but the specific malaria species responsible is unknown," says Stephanie Marciniak, a former post doctoral student in the Ancient DNA Centre and now a postdoctoral scholar at Pennsylvania State University.

"Our data confirm that the species was likely Plasmodium falciparum, and that it affected people in different ecological and cultural environments. These results open up new questions to explore, particularly how widespread this parasite was, and what burden it placed upon communities in Imperial Roman Italy," she says.

Marciniak sampled teeth taken from 58 adults and 10 children interred at three Imperial period Italian cemeteries: Isola Sacra, Velia and Vagnari. Located on the coast, Velia and Isola Sacra were known as important port cities and trading centres. Vagnari is located further inland and believed to be the burial site of labourers who would have worked on a Roman rural estate.

Using techniques developed at McMaster and abroad, researchers mined tiny DNA fragments from dental pulp taken from the teeth. They were able to extract, purify and enrich specifically for the Plasmodium species known to infect humans.

It was a difficult and painstaking process, complicated by the very nature of the disease.

Usable DNA is challenging to extract because the parasites primarily dwell within the bloodstream and organs, including the spleen and liver, which decompose and break down over time -- in this instance, over the course of two millennia.

Read more at Science Daily

Look Into the Eyes of a Neolithic Man in This Reconstruction

The face of a man who lived 9,500 years ago in the Biblical city of Jericho has been reconstructed based on extensive new analysis of the "Jericho Skull," which is the oldest portrait in The British Museum.

The Jericho Skull is a face modeled in plaster over the man's actual skull, which has now come to life in the vivid reconstruction described in the latest issue of British Archaeology.

The man's identity remains unknown, but researchers think he could have held elite status, perhaps as a revered community elder. The Jericho Skull was one of seven discovered together by famed British archaeologist Kathleen Kenyon (1906–1978) during excavations in 1953 at Jericho, a city now located in the Palestinian Territories near the Jordan River in the West Bank. The other skulls are distributed at museums across the globe.

The Jericho Skull. Tell es-Sultan, Jericho, Palestinian Authority. Human bone, plaster, shell, soil. About 8200-7500 BC, Middle Pre-pottery Neolithic B period.
"He was certainly a mature individual when he died, but we cannot say exactly why his skull, or for that matter the other skulls that were buried alongside him, were chosen to be plastered," Alexandra Fletcher, the Raymond and Beverly Sackler Curator for the Ancient Near East at The British Museum, told Seeker. "It may have been something these individuals achieved in life that led to them being remembered after death."

Fletcher added that the individuals might have also been related, since each of the skulls in the same burial were missing their second and third molars, which she said could be an inherited trait.

The Imaging and Analysis Center at the Natural History Museum completed a micro-CT scan of the Jericho Skull, which led to the construction of a 3-D digital model of the object, complete with bones inside. For the first time, hidden areas were revealed, such as the shape of his palate, cheekbones, brow ridge and eye sockets.

The researchers determined that the skull lacked a jaw. They could also see that the man had broken and decayed teeth, and that he had broken his nose during his adult life, but that it had healed before he died.

Notably, there is evidence he had undergone tight head binding from early infancy that changed the shape of his skull.

"Head binding is something that many different peoples have undertaken in various forms around the world until very recently," Fletcher explained. She said the practice of head binding in some modern cultures are intended to "make an individual appear more beautiful. In this case, the bindings have made the top and back of the head broader—different from other practices that aim for an elongated shape. I think this was regarded as a 'good look' in Jericho at this time."

The head binding adds to evidence that the man and other individuals found with him were of an elite status.

Jericho is featured prominently in the Bible. Fletcher said that in the Book of Joshua, Jericho is the first city the Israelites came to after their return from Egypt. With Joshua as their leader, they marched around the city, shouting and blowing horns, causing Jericho's walls to collapse.

"Most scholars agree that this is not an historically accurate account, but that it relates to the political situation in the Iron Age, when the territories around Jericho were vassal states of Assyria and Babylon," Fletcher said. "During this period, huge numbers of people were forcibly moved from their homes to live in different areas."

Since that Iron Age event happened around 900–500 B.C., Fletcher thinks it is unlikely that the Jericho Skull man could have been mentioned in the Bible.

Side view of the reconstruction. The effect of the head binding is just visible.
When Biblical texts were written, however, remains a heated topic for debate. Hebrew writing dating to the 10th century B.C. has led some scholars to believe that portions of the Bible were crafted during what would have been the man's lifetime.

What is clear is that when he died, his remains received special care. Someone cut a hole in his cranium. Soil was packed inside the space, to prevent the plaster applied outside of the skull from collapsing.

Human remains to this day are treated with special care, respect and dignity at The British Museum, which has a strict policy concerning how they must be handled. Because of the regulations, the researchers have not yet been able to determine the man's eye and hair color.

Read more at Discovery News

Ice Age Clues Help Explain Mysterious Slowdown of Earth's Rotation

Measurements of Earth's rotation from 720 B.C. to 2015, confirm prior research that our planet is slowing down, causing each day to become progressively longer by about two thousandths of a second per century.

While that is just a blip in time, the moments are adding up and can no longer fully be explained by tidal friction, according to the new study, published in the journal Proceedings of the Royal Society A.

"Several geophysical factors have also operated over the past 2,700 years," co-author Leslie Morrison of the International Astronomical Union told Seeker. "The reduction in the loading from the polar ice caps following the last Ice Age, which alters the shape of the Earth slightly (and its rotation), the electro-magnetic interaction between the core and mantle of the earth — and changes in mean sea level, which affect the speed of rotation."

Big earthquakes are additionally believed to have an impact, albeit minor, on Earth's rotation.

Such dynamic factors operate outside of human activities, of course, but numerous other researchers have linked man-made global warming to melting ice at the poles as well as to sea level changes, our actions could impact Earth's rotation, though very slightly, and may be doing so now.

The new paper presents the most comprehensive assembly and analysis of historical data on the rotation of Earth before the introduction of the Atomic Time scale in 1962. Morrison explained, "The Atomic Time scale is very accurate, but it covers a relatively short time span."

To study the years before 1962, Morrison and colleagues Richard Stephenson and Catherine Hohenkerk combined data from the fields of astronomy, archaeology, history and geophysics. Using gravitational theories about the orbital motion of the Earth around the sun and the moon around our planet, they computed when and where solar and lunar eclipses should have been in the past.

They next studied archaeological and historical records related to the eclipses. These records included everything from China's "Chunqiu: Spring and Autumn Annals" to translations of the Babylonian cuneiform script on thousands of clay tablets stored in the British Museum.

According to the paper's authors, the historical observations show a consistent discrepancy between the gravitational calculations and where and when the eclipses were actually seen.

"This discrepancy," Morrison explained, "is a measure of how the earth's rotation has been varying since 720 B.C., which is where the extant, reliable and accurate observations of eclipses in ancient civilizations begin."

Nevertheless, Morrison's team and other scientists are keen to understand what is driving variations in Earth's rotation. Our planet's movement, after all, affects nearly every aspect of life, from the seasons to the tides.

This image of Earth's northern hemisphere shows, via black and grey-colored areas, where polar ice used to be during the Ice Age.
Duncan Agnew, a geophysicist from the University of California at San Diego and Scripps Institution of Oceanography, told Seeker he agrees with Morrison that the primary rate differences are "probably caused by Earth's gradual change in shape caused by the end of the Ice Age. Understanding this change in shape is important in measured changes in sea level, something very important in this age of global warming. Should global warming cause major amounts of melting and a large rise in sea level, this will certainly change the earth's rotation, though by an amount that will be very small."

However small, such an additional human-caused change to Earth's rotation could affect life on our planet in ways that have yet to be determined. Richard Holme, a professor of geomagnetism at the University of Liverpool, told Seeker that "all sorts of other human effects can also influence LOD (Length of Day)."

Read more at Discovery News

Dec 6, 2016

Plants Are Even Smarter Than We Thought

Can plants learn by forming associations? They can, if you ask researchers from The University of Western Australia (WA), who say they've shown for the first time that plants can link events to learn more about their surroundings and use the associations to better their chances of survival.

The researchers focused their study on the garden pea Pisum sativum, seedlings of which they placed at the base of a Y-shaped maze. Then, in a series of training sessions, they put a fan and a light source at the end of either the same arm or opposing arms of the Y.

According to the scientists, the seedlings became better seekers of precious light by learning to associate the breeze of the fan with the location where the light would shine, growing toward that location even when the light was removed.

"The ability of seedlings to anticipate both the imminent arrival of light ('when') and its direction ('where') based on the presence and position of the fan indicates that plants are able to encode both temporal and spatial information and modify their behavior under the control of environmental cues," the scientists wrote.

The team suggested that the type of learning demonstrated by the seedlings should no longer be considered exclusive to the animal kingdom: "Our results show that associative learning is an essential component of plant behavior. We conclude that associative learning represents a universal adaptive mechanism shared by both animals and plants."

"Whilst the possibility that plants also learn by association has been considered by earlier studies," the scientists added, "our current study provides the first unequivocal evidence."

The WA scientists said they're aware of how their "smart plant" discoveries might be interpreted.

"Because our findings are unexpected, we anticipate that this study will stir a lively and exciting debate on the origin and properties of memory, learning and ultimately intelligent behavior in biological systems," said study lead Monica Gagliano, in a statement.

The researchers say their study was inspired by Russian scientist Ivan Pavlov's famed research on conditioned responses in dogs, which explored how behavior could be modified through conditioning.

Gagliano and her team have documented their findings in the online journal Scientific Reports.

From Discovery News