Oct 12, 2013
But as a recent North Carolina State University study shows, mating strategies aren't the only things changing for G. hubbsi when predators abound. The shape and size of the male fish's genitalia are also linked to the presence or absence of predators.
NC State Ph.D. student Justa Heinen-Kay and assistant professor of biological sciences R. Brian Langerhans show, in a paper published in the Journal of Evolutionary Biology, that fish coexisting with predators have longer, bonier and more elongated gonopodium tips than fish living without threat of predation. The gonopodium is the sperm-transferring organ in these livebearing fish.
Longer, bonier and more elongated gonopodium tips are, of course, relative; in small fish, these organ tips are generally only 1 millimeter long. Yet the findings suggest that male fish under constant threat of serving as a predator's snack have evolved better ways to impregnate females under these conditions.
"When predators are around, G. hubbsi males spend a lot of time attempting to mate with females because of the high mortality rate," Heinen-Kay said. "We hypothesize that G. hubbsi have evolved these bonier and more elongated gonopodium tips as a way to copulate even when females don't cooperate."
"Essentially, males need to transfer as much sperm as possible as quickly as possible, and this shape difference could help facilitate that," Langerhans said.
The researchers conducted the study in so-called "blue holes" in the Bahamas. These "big test tubes" are caves that have filled with water in the past 17,000 years; Langerhans calls them aquatic islands in a sea of land. Some of these aquatic islands contain Gambusia predators, while others do not.
Read more at Science Daily
According to a news story in The Independent:
“Joseph Atwill, who is the author of a book entitled ‘Caesar’s Messiah: The Roman Conspiracy to Invent Jesus’, asserts that Christianity did not begin as a religion, but was actually a sophisticated government propaganda exercise used to pacify the subjects of the Roman Empire.”
Atwill’s take on Jesus is of course not new. In 1844 Karl Marx famously declared religion as the opiate of the masses. History is filled with skeptics, freethinkers, atheists, agnostics and other doubters who have questioned religious doctrine and dogma.
Atwill’s claims are based on what he described as important and revealing parallels between a first-person account of first-century Judea (an ancient Roman province now part of Israel and Palestine) and the New Testament.
“What seems to have eluded many scholars is that the sequence of events and locations of Jesus ministry are more or less the same as the sequence of events and locations of the military campaign of (Emperor) Titus Flavius as described by Josephus,” Atwill wrote in a blog on his web site.
Atwill believes that the story of Jesus was actually copied and created from the biography of the Roman emperor.
Evidence for a Historical Jesus?
While Atwill’s thesis is intriguing, there are reasons to be skeptical.
“The reality is we are unlikely ever to know the ‘facts’ about Jesus,” says Ronald A. Lindsay, a Senior Research Fellow at the Center for Inquiry, a non-profit educational organization. Lindsay authored an essay on the evidence for Jesus in the book “Sources of the Jesus Tradition.”
“There are too many different stories about him, all of which have some serious credibility problems and which are inconsistent with one another,” Lindsay told Discovery News. “For the objective historian, he will always remain a shadowy figure, with little substantive biographical content. On the one hand, we have many who will take things on faith, accepting some subset of the stories as unquestionably true. On the other hand, there are those who insist that Jesus is an invented figure, a myth or a hoax. I think both of these extremes are almost equally implausible.”
Biblical scholars, as well as lay Christians, have long sought hard evidence of events and miracles described in the Bible, ranging from Noah’s Ark to the Shroud of Turin, with little success. New claims about proof of Jesus surface every few years.
For example, in 2003 a relics dealer claimed to have discovered a limestone mortuary box that held the remains of Jesus’ brother. The inscription read, “James, son of Joseph, brother of Jesus.”
The find made international news and spawned several documentaries, including one titled “The Lost Tomb of Jesus,” which aired on the Discovery Channel. Further investigation by the Israeli Antiquities Authority concluded that though the ossuary box was authentic, the inscription on it had been faked.
And just last year an historian at Harvard Divinity School claimed to have found documentary evidence in the form of a fragment of Coptic writing on papyrus that Jesus was married; a later analysis by Biblical scholars suggested the writing was hoaxed.
Read more at Discovery News
Oct 11, 2013
A team led by Mainz anthropologist Professor Joachim Burger studied bones from the 'Blätterhöhle' cave near Hagen in Germany, where both hunter-gatherers and farmers were buried. "It is commonly assumed that the Central European hunter-gatherers disappeared soon after the arrival of farmers," said Dr. Ruth Bollongino, lead author of the study. "But our study shows that the descendants of Mesolithic Europeans maintained their hunter-gatherer way of life and lived in parallel with the immigrant farmers, for at least 2,000 years. The hunter-gathering lifestyle thus only died out in Central Europe around 5,000 years ago, much later than previously thought."
Until around 7,500 years ago all central Europeans were hunter-gatherers. They were the descendants of the first anatomically modern humans to arrive in Europe, around 45,000 years ago, who survived the last Ice Age and the warming that started around 10,000 years ago. But previous genetic studies by Professor Burger's group indicated that agriculture and a sedentary lifestyle were brought to Central Europe around 7,500 years ago by immigrant farmers. From that time on, little trace of hunter-gathering can be seen in the archaeological record, and it was widely assumed that the hunter-gatherers died out or were absorbed into the farming populations.
The relationship between these immigrant agriculturalists and local hunter-gatherers has been poorly researched to date. The Mainz anthropologists have now determined that the foragers stayed in close proximity to farmers, had contact with them for thousands of years, and buried their dead in the same cave. This contact was not without consequences, because hunter-gatherer women sometimes married into the farming communities, while no genetic lines of farmer women have been found in hunter-gatherers. "This pattern of marriage is known from many studies of human populations in the modern world. Farmer women regarded marrying into hunter-gatherer groups as social anathema, maybe because of the higher birthrate among the farmers," explains Burger.
For the study published in Science, the team examined the DNA from the bones from the 'Blätterhöhle' cave in Westphalia, which is being excavated by the Berlin archaeologist Jörg Orschiedt. It is one of the rare pieces of evidence of the continuing presence of foragers over a period of about 5,000 years.
For a long time the Mainz researchers were unable to make sense of the findings. "It was only through the analysis of isotopes in the human remains, performed by our Canadian colleagues, that the pieces of the puzzle began to fit," states Bollongino. "This showed that the hunter-gatherers sustained themselves in Central and Northern Europe on a very specialized diet that included fish, among other things, until 5,000 years ago.
The team also pursued the question of what impact both groups had on the gene pool of modern Europeans. Dr. Adam Powell, population geneticist at the JGU Institute of Anthropology, explains: "Neither hunter-gatherers nor farmers can be regarded as the sole ancestors of modern-day Central Europeans. European ancestry will reflect a mixture of both populations, and the ongoing question is how and to what extent this admixture happened."
Read more at Science Dialy
Most stars (including, in about 4 billion years, our sun) end their lives as white dwarfs, after they have burned all their nuclear fuel. These super dense stellar embers exert such strong gravity that any element heavier than helium will immediately sink to the dwarf’s core. So imagine astronomers’ surprise when they discovered that some white dwarfs are cloaked in layers of “pollution” made up of silicon, oxygen, and other elements much higher up on the periodic table.
This pollution is made up of “pieces of planetary systems that are falling into their central stars,” explains Jay Farihi, an astronomer at the University of Cambridge in the United Kingdom. By measuring the pollution’s constituent elements, scientists can peer back in time and discover what the original solar system’s asteroids, comets, and planets were made of. “It’s a wonderful technique for doing planetary forensics,” says Michael Jura, a white dwarf expert at the University of California, Los Angeles, who wasn’t involved in the current research.
In GD 61’s pollution, Farihi and his colleagues noticed a curious abundance of oxygen. Their first thought was that the original asteroid must have been encrusted with carbon dioxide in the form of dry ice. Trouble is, there was no carbon anywhere to be found around GD 61. So in order to account for the extra oxygen, “the only chemically viable substance left is water,” Farihi says.
Online today in Science, the team proposes that GD 61 has “shredded” a rocky asteroid that was 26% to 28% water. About the same size as Vesta in our solar system’s asteroid belt, the asteroid likely orbited the white dwarf’s precursor, an A-type star slightly bigger than the sun. After that star died, the white dwarf’s stronger gravity probably dragged in the asteroid and tore it apart.
Water-rich asteroids are considered to be important for the formation of habitable planets, crashing into them and supplying them with life-giving liquid water. Although “we certainly can’t rewind the clock completely” to discover what GD 61’s original solar system looked like, Farihi says, the discovery of the asteroid reveals “the building blocks of Earth-like planets were there.” In the future, he hopes to look at the system with a powerful telescope like the Atacama Large Millimeter/submillimeter Array radio array in Chile to see if any of the original planets survived the death of their star, or whether anything remains of the asteroid belt where the water-rich planetesimal was born.
Read more at Wired Science
The clay balls may represent the world's "very first data storage system," at least the first that scientists know of, said Christopher Woods, a professor at the University of Chicago's Oriental Institute, in a lecture at Toronto's Royal Ontario Museum, where he presented initial findings.
The balls, often called "envelopes" by researchers, were sealed and contain tokens in a variety of geometric shapes — the balls varying from golf ball-size to baseball-size. Only about 150 intact examples survive worldwide today.
The researchers used high-resolution CT scans and 3D modeling to look inside more than 20 examples that were excavated at the site of Choga Mish, in western Iran, in the late 1960s. They were created about 5,500 years ago at a time when early cities were flourishing in Mesopotamia.
Researchers have long believed these clay balls were used to record economic transactions. That interpretation is based on an analysis of a 3,300-year-old clay ball found at a site in Mesopotamia named Nuzi that had 49 pebbles and a cuneiform text containing a contract commanding a shepherd to care for 49 sheep and goats.
How these devices would have worked in prehistoric times, before the invention of writing, is a mystery. Researchers now face the question of how people recorded the number and type of a commodity being exchanged without the help of writing.
The CT scans revealed that some of the balls have tiny channels, 1-2 millimeters (less than one-tenth of an inch) across, crisscrossing them. Woods said he's not certain what they were used for, but speculates the balls contained fine threads that connected together on the outside. These threads could have held labels, perhaps made out of wax, which reflected the tokens within the clay balls.
The tokens within the balls come in 14 different shapes, including spheres, pyramids, ovoids, lenses and cones, the researchers found. Rather than representing whole words, these shapes would have conveyed numbers connected to a variety of metrological systems used in counting different types of commodities, Woods suggested. One ovoid, for instance, might mean a certain unit, say 10, which was used while counting a certain type of commodity.
The researchers, however, were perplexed when their CT scans found one clay ball containing tokens made of a low-density material, likely bitumen, a petroleum substance. "When we make a three-dimensional model of the cavity you get this very strange amoeba like-looking shape," Woods said during the lecture.
"That's a mystery," Woods told LiveScience in an interview. "I don't really have a good answer for that," he said, adding that the bitumen tokens may represent a divergent accounting practice, or, perhaps even, that the transaction recorded involved bitumen.
In ancient Mesopotamia bitumen was used as an adhesive and to waterproof things like baskets, boats and the foundations of buildings, Woods said.
Cracking the prehistoric code
All of the clay balls contain, on the outside, one "equatorial" seal (running through the middle) and quite often two "polar" seals, running above and below.
The equatorial seals tend to be unique and more complex containing what appear to be mythological motifs; for instance a ball from the Louvre Museum shows human figures fighting what appear to be serpents. The polar seals, on the other hand, are repeated more often and tend to have simpler geometric motifs.
Based on this evidence, Woods hypothesizes the seal in the middle represents the "buyer" or recipient; the polar seals would represent the "seller" or distributor and perhaps third parties who would have participated in the transaction or acted as witnesses.
Many people would have acted as the buyers, but only a limited number of sellers or distributors would have been around to transact business with, explaining why the polar seals are repeated more often.
After a transaction of some importance was complete, one of these clay devices was created to serve as a "receipt" of sorts for the seller, as a record of what was expended. "There's a greater necessity to keep track of things that have been expended than things that are on hand," Woods said in the lecture.
Deciphering what transaction each clay ball represented is a trickier problem. Woods suspects the tokens represent numbers and metrical units. It's possible that, through the different token shapes, people in prehistoric times communicated numbers and units in a way similar to how the first scribes did 200 years later when writing was invented. If that's the case, Woods and other scientists may be able, in time, to crack the code by uncovering how token types cluster and vary.
"If they are, then there is at least some hope of deciphering the envelopes and with it uncovering the earliest evidence for complex numerical literacy," Woods said.
The amount of detail the scientists gleaned from the CT scans and 3D modeling was extraordinary, Woods said during the lecture. "We can learn more about these artifacts by non-destructive testing than we could by physically opening the envelopes," he said.
Woods will publish the full research results in the future and plans to put the images and 3D models online.
Read more at Discovery News
The WISSARD drilling program — a collaborative effort of 14 principal investigators including glaciologists, geophysicists, microbiologists and others from nine institutions across the country — is one of the largest programs ever fielded by the U.S. Antarctic Program.
The team consists of more than 50 scientists, graduate students and support staff members, who aim to explore the underbelly of the West Antarctic Ice Sheet— a flowing mass of ice about the size of France — in order to study its dynamics and improve models that predict its melting rate. If it were to melt completely, the ice sheet would increase average global sea level by between 10 to 16 feet (3 to 5 meters).
The National Science Foundation funded WISSARD in 2009 with stimulus money, providing enough resources to complete two field seasons during the Southern Hemisphere summers of 2012-2013 and 2013-2014.
Last year, the team drilled the first ever hole into a lake buried under roughly half a mile (0.8 kilometers) of ice. Researchers discovered microbial life within this remote environment, and deployed a series of environmental sensors that would measure temperature and other conditions through the following year.
For the second and final field season, scheduled for this December through early February, the team planned to collect those data loggers and drill a new hole into the grounding zone of the glacier, where the glacier's base meets the sea. This would be the first hole ever drilled into a glacial grounding zone, a region that largely controls the stability of the ice sheet and the rate at which it flows into the sea and increases sea level.
Science in jeopardy
But the National Science Foundation announced this week that it would cancel its entire U.S. Antarctic research program until the shutdown ends, jeopardizing the entire second half of the WISSARD program.
"It's heartbreaking," said Slawek Tulaczyk, a glaciologist at the University of California, Santa Cruz, and a principal investigator with WISSARD. "So many people put in their time, their passion into making sure that this happens. It takes a lot of professional, dedicated work."
Tulaczyk's team has worked through many weekends over the past three months preparing to ship scientific equipment — some of which they spent years designing specifically for this year's work — down to Antarctica to ensure that it arrives in time for their field season.
Those shipments have now stopped en route, and likely won't arrive in Antarctica by mid-November as had been scheduled.
"If we can't get stuff into the field on time, then there is no reason to see it forward," Tulaczyk told LiveScience.
The team cannot postpone the season and push it forward, because they need a full two-and-a-half months to achieve their goals, and because pushing the season further into February would pose serious safety risks: By late summer, temperatures drop well below 10 degrees Fahrenheit (12 degrees below zero Celsius), winds pick up, the sun sets earlier and search and rescue teams do not have enough visibility in the featureless white expanse of the continent to safely access emergencies.
"There is a hard deadline after which we cannot delay, because it just becomes unsafe for the personnel," Tulaczyk said.
The funding for the project ends in 2014, so the team would need special permission from the government to extend the project through 2015, which Tulaczyk said might be possible but seems unlikely.
Graduate students whose dissertations depend on this year's data are considering discontinuing their graduate programs, said John Priscu, a researcher at Montana State University and the principal investigator studying the newly discovered microbial life underneath the glacier.
"The loss of graduate student field work will diminish our efforts to train the next generation of polar scientists," Priscu said.
Read more at Discovery News
Oct 10, 2013
To put this into perspective, many great apes fail to understand human pointing, and they are genetically closer to us.
The study, published in the latest Current Biology, not only demonstrates how smart elephants are, but it also indicates that pointing is in their visual “vocabulary” too.
“By showing that African elephants spontaneously understand human pointing, without any training to do so, we have shown that the ability to understand pointing is not uniquely human but has also evolved in a lineage of animal very remote from the primates,” Richard Byrne of the University of St Andrews, who worked on the study, said in a press release.
He noted that elephants are part of an ancient African radiation of animals, including the hyrax, golden mole, aardvark and manatee.
Byrne continued, “What elephants share with humans is that they live in an elaborate and complex network in which support, empathy, and help for others are critical for survival. It may be only in such a society that the ability to follow pointing has adaptive value, or, more generally, elephant society may have selected for an ability to understand when others are trying to communicate with them, and they are thus able to work out what pointing is about when they see it.”
Byrne and co-author Anna Smet made the discovery while studying elephants whose “day job” is taking tourists on elephant-back rides near Victoria Falls, southern Africa. The elephants did receive training on some basic vocal commands, but didn’t have any lessons on pointing.
“Of course, we always hoped that our elephants would be able to learn to follow human pointing, or we’d not have carried out the experiments,” Smet said. “What really surprised us is that they did not apparently need to learn anything. Their understanding was as good on the first trial as the last, and we could find no sign of learning over the experiment.”
The researchers had seen elephants gesturing around with their trunks, but no one has yet placed any meaning to those movements. Now you have to wonder that the elephants are telling each other, “Hey, look over there,” “Look here,” and so on, all with this simple yet important gesture.
Elephants are hardly house pet material, but people who regularly interact with them are blown away by their intelligence.
Read more at Discovery News
After conducting a series of analyses, the researchers determined that a mysterious black pebble discovered years ago in the Egyptian desert is a piece of a comet nucleus — the first ever discovered.
"It’s a typical scientific euphoria when you eliminate all other options and come to the realization of what it must be," study lead author Jan Kramers, of the University of Johannesburg in South Africa, said in a statement.
The pebble, which the team has named "Hypatia" in honor of the ancient female mathematician, astronomer and philosopher Hypatia of Alexandria, is also studded with diamonds, which makes sense considering its cometary origin, researchers said.
"Diamonds are produced from carbon-bearing material," Kramers said. "Normally they form deep in the Earth, where the pressure is high, but you can also generate very high pressure with shock. Part of the comet impacted, and the shock of the impact produced the diamonds."
This impact occurred about 28 million years ago over Egypt, study team members say. The comet exploded in the atmosphere, heating the sand below to a temperature of 3,630 degrees Fahrenheit (2,000 degrees Celsius) and generating huge amounts of yellow silica glass across 2,317 square miles (6,000 square kilometers) of the Sahara Desert.
One piece of this silica glass even found its way into a brooch that belonged to the famous Egyptian pharaoh Tutankhamen, researchers said.
Comets have almost certainly struck the Earth many times over the planet's long history. But before the Hypatia pebble's origin was determined, tiny dust particles in the upper atmosphere and carbon-rich dust in Antarctic ice were the only cometary material known on Earth, researchers said.
Comets are leftover pieces from the formation of the solar system 4.5 billion years ago, so the new discovery could have valuable scientific applications as well as gee-whiz appeal.
"NASA and ESA (European Space Agency) spend billions of dollars collecting a few micrograms of comet material and bringing it back to Earth, and now we’ve got a radical new approach of studying this material, without spending billions of dollars collecting it," Kramers said.
Read more at Discovery News
The object is the remnant of a rocky planet or a large asteroid that was shredded by its burned-out star, a white dwarf known as GD 61 and located about 150 light-years from Earth.
The fingerprints of water emerged after a tally of oxygen molecules littering the star’s otherwise pristine hydrogen and helium surface. (Heavier elements like silicon and carbon sink into the dead star’s core.)
Astronomers determined the object was about 25 percent water, similar to Ceres, the largest object in our solar system’s main asteroid belt.
Earth, by comparison, is a paltry 0.02 percent water -- essentially a dry planet. Scientists believe Earth was too warm to retain any water it had during its formation and that water-rich asteroids later crashed into the planet, delivering its oceans.
“The Earth was mostly finished and then you hit it with a couple of water-rich guys and then you’re done. That’s the final bit in the recipe,” astronomer Jay Farihi, with the University of Cambridge, told Discovery News.
“Because this object had a lot of water, we know it formed in a region that is pretty similar to our main asteroid belt’s outer region,” Farihi said.
Whether the object was a large asteroid or a piece of a planet is immaterial, he added.
“Because we have rocks this big, we know that (this system) had rocky planets. You just simply cannot get to something that big without going all the way to planets. It’s a runaway process,” Farihi said.
“This is the first time we’ve seen the kind of building blocks and puzzle pieces that are necessary for habitable, water-rich planets,” he added.
Farihi and colleagues used a light-splitting spectrograph on the Hubble Space Telescope to chemically analyze GD 61 after other astronomers discovered it contained huge amounts of oxygen.
“Where the oxygen will go will determine if you’ve got water,” said Torrence Johnson, a senior scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
Johnson presented a separate study this week about how carbon-rich systems could deprive otherwise habitable planets of water, which is believed to be a key ingredient for life.
After accounting for GD 61 oxygen molecules chemically tied with silicon, magnesium, iron, calcium, aluminum and other elements, Farihi and colleagues realized there were far too many oxygen molecules left over.
The excess oxygen could have been chemically bonded with carbon to make carbon dioxide gas, but GD 61 turned out to be very carbon-poor.
“The only other chemically viable candidate is water,” Farihi said. “Water is very abundant in the universe. Oxygen combines with hydrogen pretty much wherever it can. Chemically speaking, there’s just no other alternative for this much oxygen.”
Read more at Discovery News
The planet is about the size of Jupiter, but it orbits far closer to its parent star than Mercury orbits the sun. A year on 51 Peg b lasts just four Earth days.
That got Brian Jackson, a researcher at the Carnegie Institution for Science in Washington DC, and colleagues curious if there were planets located even closer to their host stars. So they began sifting through nearly three years of data collected by NASA’s Kepler space telescope.
The observatory, now sidelined by a positioning system failure, looked for slight dips in the amount of light coming from target stars, potential telltale signs of planets passing by, or transiting, relative to the telescope’s line of sight.
Kepler was designed to seek out Earth-like worlds fortuitously positioned from their parent stars for liquid surface water, the so-called “Goldlilocks” zone believed to be favorable for life.
But staring at 150,000 stars for four years turned up thousands of other potential planets, including four candidate planets with orbits 20 times closer than Mercury circles the sun.
Surface temperatures on these planets would soar past 3,000 degrees Fahrenheit -- hot enough to melt rock.
One suspected planet, referred to as KOI-1843, circles its host star in 4.2 hours -- an orbit that brings it 40 times closer to its star than Mercury orbits the sun -- with a surface temperatures of about 4,200 degrees Fahrenheit.
Conditions on these planets would be extreme. Surfaces on their day-sides are likely molten rock, setting up the bizarre prospect of rocky vapor atmospheres that transform into “rock snow” falling on their relatively cooler night-sides.
“That could be very interesting,” Jackson told reporters during a webcast press conference at the American Astronomical Society meeting in Denver this week.
“These molten rock lakes could shed a rocky vapor atmosphere that could go screaming around to the night side of the planet and then be deposited as sort of a rock snow as the rock vapor cools,” Jackson said.
While life on these worlds is highly doubtful, finding extrasolar planets that skim their parent stars is helping scientists figure out how planets form and evolve.
“They didn’t form there, almost definitely,” Jackson told Discovery News.
For starters, temperatures in the original gas disks from which the planets formed would have been too high at the planets' current locations for them to form, Jackson pointed out.
Read more at Discovery News
Oct 9, 2013
In ancient Greece, the portico -- stoa in Greek -- was a long, open structure that often housed shops and delineated public squares from the city -- the agora.
"Porticos are well known from the Hellenistic period, from the 3rd to 1st century BC, but earlier examples are extremely rare. The one from Argilos is the oldest example to date from northern Greece and is truly unique," said Jacques Perreault, who is a specialist of the Greek Archaic period (7th and 6th centuries BC.)
Located on the edge of the Aegean Sea, the ancient city of Argilos was the first Greek colony established in this area around the great Strymon River. At its peak in the 5th century BC, Argilos was one of the richest cities in the region.
Since 1992, Professor Perreault and Dr Bonias have excavated the hill covering Argilos and the University of Montreal has acquired some of the private land sitting on it. Acquisitions were made on behalf of the Greek government, but the excavators retain the rights over scientific research. The remains of the Argilos portico are located on one of these sites, at the northern end of what was the city's commercial district, 50 metres from the port area at the time.
Traces of the inhabitants' entrepreneurship
Archaelogical digs in 2013 unearthed a roughly 40-metre length of the portico. The open area once contained seven rooms, five of which have been excavated, each measuring 5 metres wide and 7.5 metres deep, with a 2.5-metre high back wall.
Since Argilos was prosperous, it is plausible that the portico was commissioned and built by the city. If this were the case, an architect would have overseen the construction and architectural integrity of the structure; there would have been no differences in the size of the stones used, and all the rooms would have been identical.
However, examination of the remains indicates just the contrary.
"The construction techniques and the stones used are different for one room to another, hinting that several masons were used for each room," Perreault said. "This indicates that the shop owners themselves were probably responsible for building the rooms, that 'private enterprise' and not the city was the source of this stoa."
A prosperous city falls into oblivion
In the Iron Age, northern Greece was an Eldorado. The valley of the Strymon River, whose mouth is located less than three kilometres from Argilos, overflowed with gold and silver mines.
With its ports and nearby mines, Argilos was a strategic location for trade in precious metals.
But its prosperity declined rapidly from the mid-5th century BC, when the Athenians founded the nearby city of Amphipolis. In 357 BC, Philip II conquered the whole region and deported the inhabitants from Argilos to Amphipolis, the new seat of the king of Macedonia.
Thus deserted, Argilos remained frozen in time, which is why it is possible today to discover its buildings and the many vestiges of human activity that characterized them.
A popular practicum location
Since it has been under the responsibility of Perreault and Bonias, the Argilos site has provided a practicum location for some 450 University of Montreal students under their supervision.
"Each year, 20 to 30 students spend four to six weeks at Argilos to learn excavation techniques and analysis of archaeological material, and to visit various archaeological sites in northern Greece," says Perreault.
Read more at Science Daily
It was identified from its faint and unique heat signature by the Pan-STARRS 1 (PS1) wide-field survey telescope on Haleakala, Maui. Follow-up observations using other telescopes in Hawaii show that it has properties similar to those of gas-giant planets found orbiting around young stars. And yet PSO J318.5-22 is all by itself, without a host star.
"We have never before seen an object free-floating in space that that looks like this. It has all the characteristics of young planets found around other stars, but it is drifting out there all alone," explained team leader Dr. Michael Liu of the Institute for Astronomy at the University of Hawaii at Manoa. "I had often wondered if such solitary objects exist, and now we know they do."
During the past decade, extrasolar planets have been discovered at an incredible pace, with about a thousand found by indirect methods such as wobbling or dimming of their host stars induced by the planet. However, only a handful of planets have been directly imaged, all of which are around young stars (less than 200 million years old). PSO J318.5-22 is one of the lowest-mass free-floating objects known, perhaps the very lowest. But its most unique aspect is its similar mass, color, and energy output to directly imaged planets.
"Planets found by direct imaging are incredibly hard to study, since they are right next to their much brighter host stars. PSO J318.5-22 is not orbiting a star so it will be much easier for us to study. It is going to provide a wonderful view into the inner workings of gas-giant planets like Jupiter shortly after their birth," said Dr. Niall Deacon of the Max Planck Institute for Astronomy in Germany and a co-author of the study.
PSO J318.5-22 was discovered during a search for the failed stars known as brown dwarfs. Due to their relatively cool temperatures, brown dwarfs are very faint and have very red colors. To circumvent these difficulties, Liu and his colleagues have been mining the data from the PS1 telescope. PS1 is scanning the sky every night with a camera sensitive enough to detect the faint heat signatures of brown dwarfs. PSO J318.5-22 stood out as an oddball, redder than even the reddest known brown dwarfs.
"We often describe looking for rare celestial objects as akin to searching for a needle in a haystack. So we decided to search the biggest haystack that exists in astronomy, the dataset from PS1," said Dr. Eugene Magnier of the Institute for Astronomy at the University of Hawaii at Manoa and a co-author of the study. Dr. Magnier leads the data processing team for PS1, which produces the equivalent of 60,000 iPhone photos every night. The total dataset to date is about 4,000 Terabytes, bigger than the sum of the digital version of all the movies ever made, all books ever published, and all the music albums ever released.
The team followed up the PS1 discovery with multiple telescopes on the summit of Mauna Kea on the island of Hawaii. Infrared spectra taken with the NASA Infrared Telescope Facility and the Gemini North Telescope showed that PSO J318.5-22 was not a brown dwarf, based on signatures in its infrared light that are best explained by it being young and low-mass.
Read more at Science Daily
Researchers at the Swiss Ornithological Institute and the Bern University of Applied Sciences in Burgdorf, Switzerland, have collected data showing that the birds take little to no breaks during their migration from breeding grounds in Switzerland to wintering grounds in Western Africa and back again the following year. The team details their findings today (Oct. 8) in the journal Nature Communications.
To collect their data, the researchers outfitted six birds with small tags that logged acceleration and ambient light during the course of a yearlong migration cycle that began and ended in Switzerland. Only three of the six birds were recaptured the following year, but these individuals provided enough data to complete the study, the researchers said.
The team analyzed the acceleration patterns captured by the loggers to determine when the birds vigorously flapped their wings, when they glided and when they rested.
The only period of sustained resting appeared during the breeding period in Switzerland. The birds appeared to glide and flap throughout their entire migration across the Sahara Desert and their overwintering period in sub-Saharan West Africa.
"Their activity pattern reveals that they can stay airborne continuously throughout their nonbreeding period in Africa and must be able to recover while airborne," the team writes in the report. "To date, such long-lasting locomotive activities had been reported only for animals living in the sea."
Migrating sea animals, including a variety of whale and fish species, expend less energy migrating than birds do because the swimmers rely partially on their own buoyancy to help keep them afloat.
Birds expend lots of energy during flight, but Alpine swifts do not need to stop to eatbecause they feed midair on what is called aerial plankton — the atmospheric equivalent to marine plankton that can include an array of tiny bacteria, fungus, seeds, spores and small insects that get caught in air currents.
Whether or not the birds sleep in flight remains unclear, though periods of decreased movement suggest that they do, indeed, catch up on a bit of rest midair. Still, the clear lack of significant resting periods suggest that the birds do not need as much sleep to perform their migration as previous research has suggested.
"We cannot rule out that the Alpine swifts may interrupt their flight for a few minutes," the team writes. "Nevertheless, they must be able to accomplish all vital physiological functions in flight over a period of several months."
Read more at Discovery News
So says a team of scientists studying a particular type of star known as an M dwarf, or red dwarf. These long-lived stars, which are smaller than the sun, account for about 75 percent of the stars in our galaxy.
Astronomers found that M dwarf stars have relatively high levels of far-ultraviolet radiation -- 1,000 times more than the sun. These emissions could trigger chemical reactions in an orbiting planet's atmosphere that create oxygen and ozone.
"This could be taken as a false positive (for life)," said astronomer Feng Tian, with the Center for Earth System Science at Tsinghua University in Beijing, China.
"If you observe these planets’ atmospheres, you’ll see oxygen and you may think ‘Oh the oxygen could come from life, like plants on our own planet,’ but actually that is not the case," Tian told reporters during a webcast press conference at the American Astronomical Society meeting in Denver this week.
The discovery has implications for a new generation of planet-hunting observatories, such as NASA’s planned Transiting Exoplanet Survey Satellite, or TESS, a follow-on to the now-defunct Kepler space telescope.
Like Kepler, TESS will look for minute changes in the amount of light coming from target stars, which could be caused by planets passing by relative to the telescope’s line of sight. For small host stars, like M dwarfs, a transiting planet would block proportionally more of its light, making the detection easier.
"M dwarfs have been considered the fast track for the search of extraterrestrial life," Tian said.
"In order to understand whether there is life on these planets, we need to look at the photochemistry," he added
Tian and colleagues used Hubble Space Telescope data to look at the ultraviolet emissions from four M dwarf stars, including one that has three planets located in its so-called “habitable zone” where temperatures are suitable for liquid surface water.
Read more at Discovery News
Oct 8, 2013
Friendship as we know it today -- complete with BFF’s, trusted pals and more -- emerged in Africa 6 million years ago in the last common ancestor of chimpanzees and humans, a new Evolution & Human Behavior study suggests.
This clever primate literally figured out that “I’ll scratch your back if you scratch mine” makes life a lot easier.
“We know that it must have been a group-living species with relatively developed cognitive skills,” co-author Sonja Koski of the University of Zurich told Discovery News. “For example, it knew how to make and use simple tools and it understood some aspects of what other individuals are thinking. It also learned most of its necessary survival skills and knowledge socially, giving rise to the possibility of cultural differences in behavior between populations.”
“The groups consisted of many males and females, and individuals formed cooperative friendships,” she added. “Our results suggest that the preference to form these friendships with individuals much like oneself was present in the ancestor of chimpanzees and humans.”
Koski and co-author Jorg Massen of the University of Vienna found that chimpanzee buddies are remarkably similar to human friends. Both need emotionally rewarding, positive interactions with others, and these connections result in durable and mutually beneficial bonds. Chimp friendships, like human ones, can last for a very long time.
The researchers first investigated the personality similarity of friends among 38 captive chimpanzees. They determined that chimps were more likely to be friends if they possessed similar tendencies for sociability and boldness.
Sociability basically refers to how gregarious the individual is. In chimps, this is evident in grooming behaviors.
“So, highly sociable individuals hang out with others and groom them more often, while less sociable individuals are more aloof and do not groom much,” Koski explained.
She and Massen presented chimps with a stuffed leopard and an artificial snake to test boldness.
“The bold individuals approached these ‘predators’ quickly and aggressively, while the shy individuals stayed back,” she said.
Earlier research found that humans also tend to select buddies who have similar levels of friendliness and assertiveness. Traits like neuroticism, which refers to the general tendency to respond with stress and anxiety to situations, do not lead to bonding, so a more neurotic human or chimp is not likely to connect with a similarly neurotic individual.
There could be a genetic component to friendship, given that primates appear to be born more or less social and bold, with those qualities reinforced -- or not -- via environment, upbringing and experiences.
Anthropologist Joan Silk of the University of California at Los Angeles has also studied social interactions among primates. She said the new paper presents “very interesting results.”
“In our own work on baboons, we have found that certain pairs of females form social bonds that are characterized by high levels of friendly interactions and well-balanced grooming relationships; high ratios of friendly to aggressive interactions; and higher levels of support in agonistic conflicts,” Silk told Discovery News.
“Pairs that form the strongest relationships also have the most enduring relationships over time,” she continued, adding that baboons with the closest, longest-lasting friendly interactions display lowered stress levels.
Read more at Discovery News
Researchers think hundreds of people once lived in single-family stone houses within the walled settlement on Öland, a long narrow island off the southeast coast of Sweden in the Baltic Sea. But the fifth-century fort seems to have been left in ruins after an ambush, recent excavations suggest.
"I don't think anyone dared to go near it for a very long time," Helene Wilhelmson, an osteologist at Lund University said in a video released by the school.
"It's more of a frozen moment than you normally see in archaeology," Wilhelmson added. "It's like Pompeii. Something terrible happened and everything just stopped."
In an initial investigation at the site in 2010, researchers found jewelry boxes with finely-crafted gilded broaches and sets of beads, hinting at former occupation. Later, researchers found traces of a house within the fort. In the doorway, they uncovered two feet peeking out, Wilhelmson said.
The archaeologists eventually excavated the full skeleton, which had signs of blunt force trauma to the head and shoulder. So far the researchers say they have found five sets of human remains, all belonging to people who seem to have met a sudden death.
"I think they were surprised," Wilhelmson said, explaining that two of bodies were found lying close to each other by the door as if they were running out to escape when they were killed. The arrangement of the dead bodies is especially unusual for a period when people in the region traditionally burned their dead on a funeral pyre.
The archaeologists are using 3D modeling to reconstruct the 1,500-year-old crime scene. The technique will give them a chance to see, simultaneously, all the bodies where they fell even though archaeologists have removed the skeletons one by one.
"We never have the complete scene exposed at the same moment, but using the 3D models we can actually recreate the complete scene," Lund University archaeologist Nicolo Dell'Unto said in a video.
Read more at Discovery News
These findings suggest tool use could have helped to alter drastically how these ancient members of the human family tree ate and survived. In addition, the evidence suggests human ancestors may have overused the toothpick in some instances, possibly leading to swelling and infection.
The origin of the human family tree is rooted in Africa. The earliest known remains of hominids -- humans and all their extinct relatives after they split from the ancestors of chimpanzees -- that researchers have unearthed yet outside of Africa are nearly 1.8-million-year-old fossils discovered at the site of Dmanisi in the Republic of Georgia.
The remains of several hominids were previously discovered at Dmanisi, which ranged from adolescence to old age. Included within these fossils were four lower jaws, or mandibles.
"Fossil findings in human evolution are often represented by mandibles, because typically they are better preserved than any other parts of the skeleton except teeth during fossilization processes," said researcher Ann Margvelashvili, a paleoanthropologist at the University of Zurich's Anthropological Institute and Museum in Switzerland.
Mysteriously, these jaws varied widely in shape from each other, more than scientists could satisfactorily explain up to now. Some researchers suggested the discrepancies might reflect ones between the sexes within a species; others proposed they represented disparities between different species.
To help solve this puzzle, scientists analyzed how jawbones from modern hunter-gatherers from Australia and Greenland could vary and compared them with Dmanisi teeth and jaws. They relied on X-rays and microscopic analysis of these samples, focusing on the wear on teeth and the resulting changes in jawbones.
Based on their data, the researchers suggest the amount of variation seen in the Dmanisi jaws reflects the differences one might normally expect within a species. Tooth wear could, in theory, greatly augment differences between individuals by reshaping features of jawbones, such as how the rows of teeth are shaped and the height and angle of the jaws.
"Researchers should always be attentive with the details when dealing with teeth, because those details often reveal many secrets of behavior, which are not visible at first to the eye," Margvelashvili told LiveScience.
In addition, scratches on the root of a tooth in one jawbone suggested repeated toothpicking caused inflammation there.
"Dmanisi hominids show the first clear case of overusing the toothpick, which led to infection," Margvelashvili said. "The shape of the lesion reflects the shape of the toothpick."
Read more at Discovery News
High tech 4-dimensional scanning made the discovery possible. The findings are published in the journal Developmental Psychobiology.
“What we have observed are sequential events, which show maturation in the development of fetuses, which is the basis for life after birth,” lead author Nadja Reissland, of the Department of Psychology at Durham University, said in a press release. “The findings could provide more information about when babies are ready to engage with their environment, especially if born prematurely.”
Reissland and her team conducted a total of 60 scans of 15 healthy fetuses at monthly intervals between 24-36 weeks of gestation.
During the earlier part of that developmental period, fetuses frequently touched the upper part and sides of their heads.
As time went on, the fetuses began to increasingly touch the lower, more sensitive, part of their faces, including their mouths.
At 36 weeks of gestation, a significantly higher proportion of fetuses were observed opening their mouths before touching them. This suggests, according to the researchers, that later in pregnancy the fetuses were able to anticipate that their hands were about to touch their mouths, rather than reacting to the touch of their hands.
“Increased touching of the lower part of the face and mouth in fetuses could be an indicator of brain development necessary for healthy development, including preparedness for social interaction, self-soothing and feeding,” Reissland explained.
This is also likely the origin of thumb or finger sucking, done to promote calmness.
The sequence of events appears to have been programmed into us, via genetics, as part of the growth process.
As co-author Brian Francis, Professor of Social Statistics at Lancaster, said: “This effect is likely to be evolutionarily determined, preparing the child for life outside the womb.”
He continued, “Building on these findings, future research could lead to more understanding about how the child is prepared prenatally for life, including their ability to engage with their social environment, regulate stimulation and being ready to take a breast or bottle.”
Read more at Discovery News
Oct 7, 2013
The spork-faced Platybelodon’s strange jutting jaw actually consists of a second pair of flattened, widened tusks (tusks themselves being modified incisors). When the genus Platybelodon, which means “flat tooth,” and its species were first described in the 1920s, “their lower incisors were thought to function to shovel, scoop, dig and dredge soft vegetation in aquatic or swampy environments,” vertebrate paleontologist William Sanders of the University of Michigan wrote in an email to WIRED. “But recent analysis of tusk wear surfaces show that they were used more as scythes to cut tough vegetation.”
The paleontologist who proposed this slicing behavior in 1992, David Lambert, theorized that instead of roaming shorelines, Platybelodon fed on terrestrial plants, grasping branches with its trunk and cutting them away with its built-in scythe. Indeed, cross-sections of the tusks reveal a structure that provides extra strength and resistance to abrasion for such foraging, said Sanders.
So it could well be that Platybelodon wandered around Miocene Asia, Africa, and North America, scything vegetation like some sort of peasant, only without all the pesky class struggles. And it was just one of a horde of similar animals in the family Gomphotheriidae, all with modified lower tusks of varying styles. The Platybelodon genus alone had more than 15 species, reaching “the apex of development of these lower tusks,” according to Sanders. Their radically flattened teeth suggest “strong selection for specialized feeding on a particular range of plants,” which was crucial given that “for much of the Miocene there were often three to five or more genera of proboscideans occurring in the same landscape, competing for forage.”
Pegging the various appearances of such proboscideans, though, is difficult, because flesh-like schnozes don’t fossilize as easily as bone. We’re actually quite lucky to have Platybelodon preserved at all, considering that fossilization is a really hard thing to pull off. Even if you can avoid getting carted off in a dozen different directions by scavengers, you need to settle in the right spot. And Platybelodon just so happened to do us a solid by dying — sometimes en masse — next to or in rivers, the prime locales for fossilization.
But “think about what an elephant looks like,” Sanders asks us. “The trunk is a very separate entity from the mouth. You have to be able to get food into your mouth, and if your front limbs are occupied in posture, and you have upper and lower tusks that would make it difficult to have a long projecting tongue or mobile lips, then you need a proboscis.”
Read more at Wired Science
The T. rex was set to leave its current home in Montana on Friday (Oct. 11) for a cross-country road trip. As part of a new loan agreement, the Smithsonian, the world's most visited natural history museum, will be the dinosaur's steward for the next 50 years.
But Smithsonian magazine, the official journal of the institution, reported that the T. rex transfer has now been postponed until April.
"It's a major specimen, so we're being very prudent about how we handle it," Kirk Johnson, the museum's director, told Smithsonian magazine. "There's a lot of uncertainty with the shutdown, and uncertain availability of federal workers to do the work that we need to do."
The fossil's planned arrival at the Smithsonian on Oct. 16 was meant to coincide with the fourth annual National Fossil Day. The museum typically receives 7.3 million visitors per year, according to its website. It is closed in the wake of the shutdown, and most of its staff has been furloughed.
The dinosaur has been dubbed the Wankel T. rex after Kathy Wankel, a rancher and amateur fossil hunter who discovered its arm bones in Montana's Fort Peck reservoir in 1988. Since it was unearthed on federal lands, the dinosaur belongs to the U.S. Army Corps of Engineers. That agency had loaned the fossil to the Museum of the Rockies at Montana State University in Bozeman, where it was prepared and put on display in its original "death pose" for two decades.
The T. rex, which measures 38 feet (11.5 meters) long and weighs 7 tons (6.3 tonnes), will be the centerpiece of the Smithsonian's new dinosaur hall, scheduled to open in 2019. The new wing will feature other key specimens from the Smithsonian's collection of 46 million fossils.
Read more at Discovery News
All of these activities are suggested by remains found at a prehistoric Danish butchering site, called Lundy Mose, which is described in a paper accepted for publication in the Journal of Archaeological Science.
Bone fragments belonging to wild boar, red deer and aurochs were unearthed. But the hunters clearly had a taste for elk meat, since elk remains were prevalent at the site, located in South Zealand, Denmark.
“Due to very good conditions of bone preservation, Lundby Mose offers exceptional opportunities for detailed reconstruction of exploitation patterns, and allows a very precise picture of the different activities involved in elk exploitation,” archaeologist Charlotte Leduc of the University of Paris wrote.
Her detailed analysis of the remains determined that the hunters first cut around the elk heads and other parts of the body in order to remove the hides. At least one of the hides then likely became a perishable container, comparable to a garbage bag, upon which refuse was placed and later bundled.
The hunters then removed meat from easy-to-access parts, such as the limbs, and likely feasted on it right then and there. No roasting pit or evidence for fire is mentioned, so it might have been consumed raw.
All skeletal parts containing marrow -- now a delicacy in many fine restaurants -- were fractured to enable its extraction.
Wietske Prummel of the University of Groningen, who analyzed another prehistoric Northern European butchering site, told Discovery News that marrow was usually “consumed by hunters immediately after butchering. It was their reward for the successful kill.”
The hunters skillfully cut around the body, trimming fat and boning meat for later easy consumption. Leduc thinks much of the meat could have been transported to a nearby settlement site.
Before that happened, however, the hunters removed select bones, such as from the long limbs, likely for making bone weapons and tools. They also removed the antlers.
The elk's shoulder blade bones were taken out and afterwards, back at the settlement, “were sometimes worked and used presumably as knives for fish processing,” Leduc suspects.
As the hunters worked, they appear to have dumped waste material onto the reserved hide. It was later tossed into a nearby lake.
The front teeth of the elks were missing, suggesting “a specific status of front teeth for the hunters,” according to Leduc. Other prehistoric hunt scenes support this theory, as do discoveries of prehistoric tooth bling.
This series of events likely played out countless times, even long before 12,000 years ago.
“Modern humans hunted and butchered large game and cooked the meat from circa 45,000 years ago when they arrived in Europe," Marcel Niekus of the University of Groningen, told Discovery News.
Read more at Discovery News
This was predicted because the distant world was passing its summer season and heading out billions of miles farther from the sun along a highly elliptical orbit. The warning worked. Launched in 2006, NASA’s New Horizons probe is now sprinting toward a 2015 rendezvous with Pluto as the fastest manmade object ever built.
But don’t worry if the long distance runner doesn’t get there soon enough. New observations by Catherine Olkin of the Southwest Research Institute in Boulder, Colo., predict that the tenuous nitrogen-methane-carbon monoxide atmosphere will remain buoyant year ’round. In fact, as Pluto enters late summer, the atmosphere is now three times denser than when first measured in 1988. That means it isn’t going anywhere.
These results provide insights into the nature of Pluto’s surface crust, say the researchers. To explain the atmospheric changes there must be a rock-hard water-ice surface that apparently soaks up feeble sunlight and holds onto the heat it for a long time.
Some astronomers have previously dismissed Pluto as an oversized comet nucleus. A comet forms a temporary atmosphere, called a coma, when it is close enough to the sun for surface ices to warm and sublimate. Some scientists called Pluto’s atmosphere just a giant and temporary coma. But comets have frothy surfaces that lose heat quickly and Pluto doesn’t according to the researchers.
We’ve never had an opportunity to observe what really happens during winter on Pluto because it was springtime on the icy world when it was discovered in 1930. Pluto’s summer happened in the late 1980s when it swung inside Neptune’s orbit.
Because of its sluggish 248-year orbit, Pluto won’t be deep into winter until the year 2130. (Astronomers won’t be able to celebrate Pluto’s completion on one orbit since its discovery until the year 2178! Imagine what Earth history will have transpired by then.)
The team looked at Pluto observations taken from 1988 to 2003. These were occultation events where Pluto passes in front of a background star and astronomers can measure the light filtered through Pluto’s atmosphere. This allows for precise measurement of atmospheric pressure. The team made observations this year to show the atmosphere is thicker than ever before measured. Still, the anemic atmosphere is just one one-hundred-thousandth the surface pressure of Earth’s atmosphere.
Read more at Discovery News
Oct 6, 2013
The Thylacoleo Caves, 100 kilometers north-west of Eucla in Western Australia, were named after the ancient Pleistocene marsupial "lion"(Thylacoleo carnifex), which was found in the cave.
Most research in the cave has focused on describing the diverse marsupial fauna, including giant kangaroos (procoptodon) and giant wombats (phascolonus).
But avian palaeontologist Elen Shute, a Ph.D. candidate at Flinders University in Adelaide, has turned her attention to describing the diverse range of birds that have been found trapped in the layers of dirt on the cave floor.
She presents her research today at the 14th biennial Conference on Australasian Vertebrate Evolution, Palaeontology & Systematics.
"It's turning out to be a very diverse site in comparison to other Australian Pleistocene cave fossil deposits," said Shute.
Shute, under the supervision of Dr Gavin Prideaux and Dr Trevor Worthy from the University of Adelaide, has identified more than 40 bird species from the cave site.
"It includes pigeons, birds of prey, a lot of parrots and buttonquails. Interestingly there are three types of megapodes, sometimes called mound builders, including a giant malleefowl."
There are also the remains of several duck species suggesting lakes may have formed part of the environment during the Pleistocene -- a stark contrast to the dry plains and saltbushes that make up the Nullarbor today.
Shute said the diverse range of bird species helps paint a clearer picture of past conditions.
"If you're able to determine a large number of species from a cave deposit you can use overlaps in habitat preferences to draw conclusions about the environment," she explained.
According to Shute, the most exciting discoveries, which are yet to be formally described, are birds that appear to resemble coucals and logrunners.
Today, coucals are found in the tropics and subtropics of northern and eastern Australia, while the logrunner tramps around the rainforests of northern Australia and Papua New Guinea -- more than 4000 kilometers away.
"So we're probably looking at the persistence of thick vegetation [in the Nullarbor], at least at certain times, in the recent past," she said.
Read more at Discovery News
The ringed planet Saturn, sinking into the west-southwest twilight, is close to Mercury in early October. About 40 minutes after sunset on Sunday, try catching a glimpse of Saturn hovering about 5 degrees above a razor-thin sliver of a crescent moon that's just two days past new phase and a mere 4 percent illuminated by the sun.
Brighter Mercury will be situated about 2.5 degrees to the moon's lower left. Your clenched fist held at arm’s length measures roughly 10 degrees, so Saturn and the moon will be separated by half a fist. And the separation between Mercury and the moon will be half of that.
This will be a challenging observation, because all three celestial objects will be very low and possibly dimmed by haze, which is seemingly always thickest down near the horizon. In addition, the background sky will still be quite bright. (Binoculars will be a great help.)
You might have a better chance of seeing this trio if you live in the southern United States, for all three will appear somewhat higher from there as opposed to the view from the northern U.S. or southern Canada. This will probably be your last chance to see Saturn in the evening sky before it transitions into the morning sky early next month.
Better on Tuesday
Two nights later will be a different story. On Tuesday evening, the moon will be about three times higher and more than four times wider (18 percent illuminated), making it a much more obvious target to see with both binoculars and your naked eye.
And its companion will be the brightest of all planets, Venus. This dazzling evening star, shining with a radiance 48 times brighter than Mercury and 85 times that of Saturn, will be readily visible hovering about 7 degrees below and slightly to the right of the moon. In spite of the rather wide gap separating them, both will make for an eye-catching sight in the southwestern sky.
Glittering Venus flames into view soon after sunset. Ever since late last spring it has remained at about the same low altitude in the dusk (for viewers at mid-northern latitudes); it’s hardly any higher after sunset than it has been since June, but three factors are improving its visibility nonetheless:
It is growing a little brighter as it rounds the sun and speeds toward Earth;
Twilight fades faster in the fall than in summer, leaving Venus to shine in a darker sky;
It has shifted from the west to the southwest. Objects at a given altitude above the horizon in the southern part of the sky take longer to set than objects at the same altitude due west.
Venus is also finally climbing higher during October, and it now stays above the horizon until twilight is long over. The planet will be at its highest (and best position for viewing) in late November and early December.
Getting better in telescopes
Behind Venus, Antares and the other stars of Scorpius, a "summer" constellation, slide westward during October on their way out for the year.
On the evening of Oct. 16, look for the 1st-magnitude star Antares -- the Heart of the Scorpion -- shining south (to the lower left) of Venus by just 1.5 degrees; that’s about a finger’s width at arm’s length. Antares twinkles with a distinct reddish hue and is less than 1 percent as bright as Venus.
Telescopically, Venus is becoming a more interesting sight as it draws nearer to Earth and becomes less gibbous. Watch it change in phase from two-thirds illuminated now to half-lit around the end of the month.
Read more at Discovery News