Mar 31, 2012

Clocking an Accelerating Universe: First Results from BOSS

Some six billion light years ago, almost halfway from now back to the big bang, the universe was undergoing an elemental change. Held back until then by the mutual gravitational attraction of all the matter it contained, the universe had been expanding ever more slowly. Then, as matter spread out and its density decreased, dark energy took over and expansion began to accelerate.

Today BOSS, the Baryon Oscillation Spectroscopic Survey, the largest component of the third Sloan Digital Sky Survey (SDSS-III), announced the most accurate measurement yet of the distance scale of the universe during the era when dark energy turned on.

"We've made precision measurements of the large-scale structure of the universe five to seven billion years ago -- the best measure yet of the size of anything outside the Milky Way," says David Schlegel of the Physics Division at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), BOSS's principal investigator. "We're pushing out to the distances when dark energy turned on, where we can start to do experiments to find out what's causing accelerating expansion."

How to measure expansion in an accelerating universe

Accelerating expansion was announced less than 14 years ago by both the Supernova Cosmology Project (SCP) based at Berkeley Lab and the competing High-z Supernova Search Team, a discovery that resulted in 2011 Nobel Prizes for the SCP's Saul Perlmutter and High-z Team members Brian Schmidt and Adam Riess. Acceleration may result from an unknown something dubbed "dark energy" -- or, dark energy may be just a way of saying we don't understand how gravity really works.

The first step in finding out is to establish a detailed history of expansion. Unlike supernova searches, which depend on the brightness of exploding stars, BOSS uses a technique called baryon acoustic oscillation (BAO) to determine the distances to faraway galaxies.

Baryon acoustic oscillation measures the angle across the sky of structures of known size, the peaks where galaxies cluster most densely in the network of filaments and voids that fill the universe. Since these density peaks recur regularly, the angle between appropriate pairs of galaxies as precisely measured from Earth reveals their distance -- the narrower the apparent angle, the farther away they are.

Knowing the distance to an object tells its age as well, since its light travels from there to here at known speed. And the redshift of the light reveals how the universe has expanded since that time, as expansion stretches space itself; the wavelength of light traveling through space toward Earth stretches proportionally, becoming redder and revealing the expansion of the universe since the light left its source.

"BOSS's first major cosmological results establish the accurate three-dimensional positions of 327,349 massive galaxies across 3,275 square degrees of the sky, reaching as far back as redshift 0.7 -- the largest sample of the universe ever surveyed at this high density," says Martin White of Berkeley Lab's Physics Division, a professor of physics and astronomy at the University of California at Berkeley and chair of the BOSS science survey teams. "BOSS's average redshift is 0.57, equivalent to some six billion light-years away. BOSS gives that distance to within 1.7 percent -- 2,094 megaparsecs plus or minus 34 megaparsecs -- the most precise distance constraint ever obtained from a galaxy survey."

The origin of BAO, the regular clustering of ordinary matter (called "baryons" by astronomical convention), was the pressure of sound waves (thus "acoustic") moving through the universe when it was still so hot that light and matter were mixed together in a kind of soup, in which the sound waves created areas of regularly varying density ("oscillation"). By 380,000 years after the big bang, expansion had cooled the soup enough for ordinary matter to condense into hydrogen atoms (invisible dark matter was also part of the soup) and for light to go its separate way.

At that moment variations in density were preserved as variations in the temperature of the cosmic microwave background (CMB), a phenomenon first measured by Berkeley Lab astrophysicist George Smoot, for which he shared the 2006 Nobel Prize. The warmer regions of the CMB signal areas where the density of matter was greater; these regions seeded the galaxies and clusters of galaxies that form the large-scale structure of the universe today. Thus the cosmic microwave background establishes the basic scale of baryon acoustic oscillation used to measure the expansion history of the universe.

BOSS's data on galaxy clustering and redshifts can be applied not only to BAO but also to a separate technique called "redshift space distortions" -- a direct test of gravity that measures how fast neighboring galaxies are moving together to form galaxy clusters.

What if dark energy isn't an unknown force or substance, but instead a shortcoming of Albert Einstein's General Theory of Relativity, our best-yet theory of gravity? General Relativity predicts how fast galaxies should be moving toward one another in galaxy clusters, and, in the aggregate, how fast the structure of the universe should be growing. Any departure from its predictions would mean the theory is flawed.

"We depend on redshift to know expansion rates and how structure was growing at different times in the past," says Beth Reid, a Hubble Fellow at Lawrence Berkeley National Laboratory who directed the BOSS study of redshift space distortions. "But redshifts aren't uniform. Galaxies are carried along in the Hubble flow as the universe expands, but they also have their own velocities. They tend to fall toward denser regions, for example. Because the ones on the far side of a dense region are coming toward us, their redshift makes them look closer than they really are; the opposite is true for the galaxies on the near side, which are falling away from us -- they look farther away."

Statistical analysis of the redshifts of the hundreds of thousands of galaxies in the BOSS dataset can take into account the peculiarities of local variation and still produce a dependable measure of distance, the Hubble expansion rate, and the growth rate of structure in the universe. With these techniques, Reid and her colleagues have measured gravity on a scale of 100 million light years, far larger than the most accurate gravity measure yet, which is based on the distance from Earth to the moon. Their conclusion: Einstein was right.

Read more at Science Daily

Crocodiles Trump T. Rex as Heavyweight Bite-Force Champions, New Study Shows

Paul M. Gignac, Ph.D., Instructor of Research, Department of Anatomical Sciences, Stony Brook University School of Medicine, and colleagues at Florida State University and in California and Australia, found in a study of all 23 living crocodilian species that crocodiles can kill with the strongest bite force measured for any living animal. The study also revealed that the bite forces of the largest extinct crocodilians exceeded 23,000 pounds, a force two-times greater than the mighty Tyrannosaurus rex.

Their data, reported online in PLoS One, contributes to the understanding of performance in animals from the past and provides unprecedented insight into how evolution has shaped that performance.

In "Insights into the Ecology and Evolutionary Success of Crocodilians Revealed through Bite-Force and Tooth-Pressure Experimentation," the researchers detail their examination of the bite force and tooth pressure of every species of alligator, crocodile, caiman, and gharial. Led by Project Director Gregory Erickson, Ph.D., Professor of Biological Science at Florida State University, the study took more than a decade to complete and required a diverse team of croc handlers and scientists.

"Crocodiles and alligators are the largest, most successful reptile hunters alive today, and our research illustrates one of the key ways they have maintained that crown," says Dr. Gignac.

The team roped 83 adult alligators and crocodiles and placed a force meter between their back teeth and recorded the bite force. They found that gators and crocs have pound-for-pound comparable maximal bite forces, despite different snouts and teeth. Contrary to previous evolutionary thinking, they determined that bite force was correlated with body size but showed surprisingly little correlation with tooth form, diet, jaw shape, or jaw strength.

Dr. Gignac emphasizes that the study results suggest that once crocodilians evolved their remarkable capacity for force-generation, further adaptive modifications involved changes in body size and the dentition to modify forces and pressures for different diets.

The team has been contacted by editors of the "Guinness Book of World Records" inquiring about the data.

Among living crocodilians, the bite-force champion is a 17-foot saltwater croc, with a force measured at 3,700 pounds.

"This kind of bite is like being pinned beneath the entire roster of the New York Knicks," says Dr. Gignac, illustrating the tremendous force displayed by the living creatures. "But with bone-crushing teeth."

Read more at Science Daily

Mar 30, 2012

How to Become a Planet Hunter

This last month saw a boom in planetary sightings across the world. Wherever you observed the night sky from you couldn't fail to have seen, and been impressed by, the view of Venus and Jupiter dancing around in the twilight after the sun had set.

While these two planets were setting, Mars and Saturn were rising in the East, continuing the celestial show. It's easy enough to still spot these planets with the naked eye, but to really get the most out of them a telescope or powerful binoculars are needed.

There is no better time than now to learn about how to get the most out of your equipment for planet spotting.

First things first: magnification. To be able to see any decent level of detail, a magnification of at least 20 is needed. Anything less than this and you'll just see the planets as bright stars.

Telescopes can easily handle this magnification, but if you are using hand-held binoculars you might want to think about getting a tripod to mount them on. Not only will the binoculars magnify the object under study by 20 times, but any tiny movement caused by hand shake will also be magnified leading to a very wobbly and unpleasant view.

Binoculars usually have a fixed magnification, which is described by a set of numbers -- for example, "7x50" means "7 times magnification" and "a lens diameter of 50 millimeters."

To work out the magnification of a telescope, you divide the focal length of telescope by the focal length of the eyepiece -- for example 1000 millimeters (telescope) divided by 15 millimeters (eyepiece) would give a magnification of 67 times.

If you are using a telescope, and magnifying the planets much more than a set of binoculars are capable of, you may still find that you get a very disappointing view. This is caused by a few factors.

The most common cause of poor-detailed images is atmospheric conditions. If the atmosphere is very turbulent (i.e. the 'seeing' is poor) then the incoming light from the planet will get bounced around as it passes through the atmosphere, leading to a 'bubbly' or rapidly changing image.

You may get moments of good seeing but you'll require some patience. There is nothing you can do about poor atmospheric seeing and you can tell if this is the case as the stars are 'twinkling' more than usual.

Another cause of poor image quality may be the result of not letting your telescope cool down. Telescopes can take quite some time to cool (sometimes hours) so it's worth setting up your telescope outside before nightfall to let it cool -- but be careful about dew forming on the optics!

Another cause of poor image quality is collimation, particularly in reflecting telescopes that use mirrors. Make sure the optics are all aligned properly and you can be sure you are getting the best out of your telescope.

Now that you have a nice sharp image of your favorite planet you might like to try enhancing the view you can see through the use of color filters:

  •     Venus is generally quite bland and seemingly featureless but a deep blue filter can enhance subtle detail in its thick atmosphere.
  •     Mars has lots of detail accessible to the amateur astronomer, but more can be seen. Try an orange/red filter to increase the contrast between dark and light areas like the popular Syrtis Major region or perhaps a green/blue filter to enhance the polar ice caps.
  •     Jupiter is a great target and detail in the bright areas of the gas giant's belts can be enhanced with a light blue filter and the darker belts like the northern and southern equatorial belts can be enhanced by a green or blue filter.
  •     Saturn's stunning ring system can be enhanced by a light green filter, which will also pull out detail in the belts of the planet's atmosphere.
Read more at Discovery News

Martial Arts Celeb Recruited for Ancient Roman Army

Millennia before modern-day military recruiters talked up potential soldiers in shopping malls or put up posters, one Roman city took a rather different approach to recruiting soldiers for the emperor's army.

A newly translated inscription, dating back about 1,800 years, reveals that Oinoanda, a Roman city in southwest Turkey, turned to a mixed martial art champion to recruit for the Roman army and bring the new soldiers to a city named Hierapolis, located hundreds of miles to the east, in Syria.

His name was Lucius Septimius Flavianus Flavillianus and he was a champion at wrestling and pankration, the latter a bloody, and at times lethal, mixed martial art where contestants would try to pound each other unconscious or into submission.

Flavillianus proved to be so successful as a military recruiter that it was decreed that he be made a "cult figure in the band of heroes" after he died, with each tribe of the city erecting statues in his honor. The inscription, written in Greek, was engraved on the base of a statue found in Oinoanda's agora (a central public space) and would have been erected by the people of the city. Discovered by a team in 2002, it wasn't until now that researchers translated and published it.

"This is a very unusual piece of evidence that has come to light," said Nicholas Milner, a researcher with the British Institute at Ankara, who published the translation in the most recent edition of the journal Anatolian Studies.

Milner explained that in the Roman Empire, this sort of "heroisation" is very rare.

Champion athlete

The inscription hails Flavillianus as being a "champion athlete," and, from other inscriptions found at Oinoanda, researchers know that the two sports he won championships in were wrestling and pankration.

Pankration was such a bloody sport that it had only two known rules: no eye-gouging and no biting. Aside from these restrictions, anything was fair game. Philostratos, an ancient writer who lived around the same time as Flavillianus, wrote that pankration competitors are skillful in different types of strangulation. "They bend ankles and twist arms and throw punches and jump on their opponents," (Translation from the book "Arete: Greek sports from ancient sources," Stephen Gaylord Miller, 2004).

By the time he took up duties recruiting soldiers Flavillianus would have been a mature man who had fought and prevailed in many of these contests. His father even boasted about his son's success in an inscription on his own mausoleum writing that Flavillianus, "who having trained at pankration won crowns for victories in sacred games."

This experience as a champion fighter, and the fame that came with it, would have helped Flavillianus in his task. "He would have been able to judge suitable recruits, and he probably knew lots of suitable recruits," said Milner.  Also "being a top athlete was a kind of celebrity status in Roman times," he said. "A celebrity would have a greater ability to drum up support and large numbers of volunteers than somebody who was not a celebrity." It is possible, however, that some of the soldiers Flavillianus recruited were conscripted against their will.

Man of mystery

Flavillianus would have personally escorted his recruits to Hierapolis, but beyond that, Milner said, scholars don't know if the champion joined the Roman army himself.

Milner isn't sure why Flavillianus became an army recruiter, though he suggests he was likely motivated by honor. If he hadn’t done the job it would have fallen to the community at large (especially those who were wealthy) to drum up recruits.

"This was a society that was driven by the competition for honor, particularly at the top of the city," Milner explained. "They were competing to outshine one another in the eyes of their local community and hopefully also in the eyes of the Roman authorities."

Read more at Discovery News

Cows Almost Impossible To Domesticate, DNA Reveals

Cattle aren't known for their intelligence. Perhaps it's because their family tree has a very skinny trunk.

Genetic evidence suggests all "taurine" cattle (the most commonly recognized breed) descend from only about 80 females and came from a single region in what is now Iran about 10,500 years ago. A study in the journal Molecular Biology and Evolution traced the modern global herd's heritage back to its ancestral home on the range.

The study compared mitochondrial DNA extracted from 15 preserved ancient cattle's bones to modern cattle and found little variation. Little variation meant the founding population didn't have many different versions of the mitochondrial genes to start with.

Earlier research published in PloS ONE suggested that taurine cattle may have later received a small genetic boost from European aurochs. Aurochs were the super-sized ancestors of our modern hamburger on the hoof.

The size and nasty disposition of the wild auroch (Bos primigenius) would have made it a formidable beast to tame for the ancient Iranians. That difficulty is possibly why domestication only occurred with a small number of animals. The authors of the paper in Molecular Biology and Evolution suggested that only humans who had settled down into villages would have had the ability to domesticate the auroch.

"Importantly, the two sites showing the earliest signs of the wild auroch's domestication -- Dja´de and Çayönü -- are less than 250 kilometers (155 miles) apart," wrote the multinational group of authors led by Ruth Bollongino of the University of Mainz, Germany.

"Interestingly, archaeological signs of sedentism during the 9th millennium B.C. are restricted to the same region," according to the paper. "It is conceivable that the management of wild cattle was too challenging for the mobile population of the surrounding mountainous areas where goat was the preferred domestic species."

Read more at Discovery News

Take a Hike for Earth Hour

For Earth Hour on Saturday, March 31, at 8:30 p.m. the world will see a little less glitz and more natural glamor as lights go out for an hour. I recommend taking the day and going for a hike - somewhere flashlights shine rather than street lights and when you turn off the lights the stars are so bright they feel like they are just beyond the edge of Earth's horizon.

Just make sure you turn off the lights at home before you go.

The International Space Station will be observing city lights around the globe as we observe Earth Hour. The best time to observe the ISS from the United States, however is in the early hours of the morning on Saturday and Sunday. You can track its progress here.

Read more at Discovery News

Mar 29, 2012

Age of oldest rocks off by millions of years

Two of the solar system's best natural timekeepers have been caught misbehaving, suggesting that the accepted ages for the oldest known rock samples are off by a million years or more.

According to two new studies, a radioactive version of the element samarium decays much more quickly than previously thought, and different versions of uranium don't always appear in the same relative quantities in earthly rocks.

Both elements are used by geologists to date rocks and chart the history of events on our planet and in the solar system.

"If you have a critical event in Earth's history, something like an extinction event or a climate change shift or a meteorite impact, you need to know the absolute age with the most confidence," says Joe Hiess of the British Geological Survey, who led one of the studies. "In Earth sciences there's a need to be able to define what happened first and what happened second."

Chronometer shortage

Geochemists age rocks by measuring the ratio of radioactive isotopes – versions of the same element with different atomic masses – in them. Because the elements decay from one isotope, or element, to another at a constant rate, knowing the ratio in a particular rock gives its age.

Different elements and isotopes decay at vastly different rates. Scientists pick one that suits the timescale of interest. One of the favourites for tracing events in the early solar system, such as when the Earth's crust differentiated from its mantle or when the lava oceans on the moon solidified, is samarium-146, a hard shiny metal found in many minerals in the Earth's crust.

"In this time window, there are not many other chronometers," says Michael Paul of the Hebrew University in Jerusalem.

Scientists have measured samarium-146's half-life – the time taken for exactly half of a sample of atoms to decay radioactively - four times over the past 60 years, and got different answers each time. The two most recent measurements seemed to converge on a half-life of 103 million years, plus or minus 5 million years. But Paul and colleagues suspected that that number wasn't quite right. So they used a technique called accelerator mass spectrometry, which Paul says is less likely to be skewed by experimental errors.

Youthful meteorites

They found that the half-life is just 68 million years, 30 per cent shorter than thought. That means that every rock dated by samarium-146 decay – which include some of the oldest on Earth and the moon, and even some Martian meteorites – formed 20 million to 80 million years earlier than thought.

In a solar system that's 4.5 billion years old, tens of millions of years "is a lot", Paul says. "It means everything was forming more quickly."

There was a second, separate hiccup. Earth's oldest rocks are also aged using isotopes of uranium, which decay into isotopes of lead. Until a few years ago, geochemists assumed that the ratio of uranium-238 to uranium-235 was constant – 137.88 – in all rocks, and therefore the ratio of lead isotopes was the only measurement needed to date the rocks. But high-precision measurements of early materials found in meteorites or rocks formed in oceans showed differences.

Hiess and colleagues made the most wide-ranging study of uranium isotope ratios yet, using 45 samples of zircon from all over the world (pictured, above right). Zircon was one of the first minerals to solidify on Earth, it resists weathering and melting, and it holds on to uranium well, so it's a good candidate for dating old rocks.

Read more at New Scientist

One Person Adds 37 Million Bacteria to a Room

Just one person in a room adds 37 million bacteria to the air every hour, according to a study published in the journal Indoor Air.

Most of the bacteria is stirred up from the floor, left behind by the room's prior occupants.

"We live in this microbial soup, and a big ingredient is our own microorganisms," Jordan Peccia, associate professor of environmental engineering at Yale and the principal investigator of the study, said in a press release.

"Mostly people are re-suspending what's been deposited before. The floor dust turns out to be the major source of the bacteria that we breathe."

Not long ago research revealed what lives in your belly button, so the overall amount of bacteria is astounding.

This latest study is the first to quantify how much a lone human presence affects the level of indoor biological aerosols (microorganisms).

Peccia and his team measured and analyzed biological particles in a single, ground floor university classroom over a period of eight days: four days when the room was periodically occupied, and four days when the room was continuously vacant. At all times the windows and doors were kept closed.

The HVAC system was operated at normal levels. Researchers sorted the particles by size.

The scientists found that "human occupancy was associated with substantially increased airborne concentrations" of bacteria and fungi of various sizes. Occupancy resulted in especially large spikes for larger-sized fungal particles and medium-sized bacterial particles.

The size of bacteria and fungi-bearing particles is important, because size affects the degree to which they are likely to be filtered from the air or linger and recirculate.

"Size is the master variable," Peccia said.

Read more at Discovery News

Neanderthals Were Dying Out Before Humans Arrived

Neanderthals in Western Europe started disappearing long before Homo sapiens showed up, suggesting that cold weather, and not cold-hearted humans, might have been responsible for the species' ultimate demise.

The findings, published in the journal Molecular Biology and Evolution, suggest that at least one population of Neanderthals was vulnerable to climate change.

Love Dalén, lead author of the paper, told Discovery News that "even if the Neanderthals were capable of surviving periods of extreme cold, the game species they relied on likely could not, so their resource base would have been severely depleted."

Neanderthals appear to have favored hunting wooly mammoths and other big game. Neanderthals were also big-brained, with the ability to make stone tools, construct garments, control fire and find shelter.

For the study, Dalén of the Swedish Museum of Natural History and his colleagues analyzed mitochondrial DNA sequences from 13 Neanderthal individuals, including a new sequence from the site of Valdegoba cave in northern Spain.

The researchers found that Neanderthals from Western Europe, Asia and the Middle East that were older than 50,000 years showed a high degree of genetic variation, on par with what might be expected from a species that had been abundant in those areas for a long period of time.

But Neanderthals from Western Europe younger than 50,000 years ago showed an extremely reduced amount of genetic variation. The scientists believe this means the earlier population of Neanderthals there was dwindling.

"We argue that Neanderthals disappeared in Western Europe for a period of time," co-author Rolf Quam, a Binghamton University anthropologist, told Discovery News.

"Subsequently, the region was re-occupied by individuals from a surrounding region," Quam added. "It is not possible, based on the current genetic data, to determine the geographic region of this new source population."

The scientists suspect that climatic conditions were not as extreme in the surrounding areas at the time, so that Neanderthals were able to move back into Western Europe. At present, there is no clear evidence of Homo sapiens being in Europe earlier than about 35,000 to 40,000 years ago, according to Quam -- so it seems humans did not play a role in the early Neanderthal population's demise.

Read more at Discovery News

Monster Solar Tornadoes Discovered

For the first time, huge solar tornadoes have been filmed swirling deep inside the solar corona -- the sun's superheated atmosphere. But if you're imagining the pedestrian tornadoes that we experience on Earth, think again.

These solar monsters, measuring the width of several Earths and swirling at speeds of up to 300,000 kilometers (190,000 miles) per hour, aren't only fascinating structures; they may also trigger violent magnetic eruptions that can have drastic effects on our planet.

In one example observed on Sept. 25, 2011, solar researchers from the UK used the high-definition cameras onboard NASA's Solar Dynamics Observatory (SDO) to track solar gases as hot as 2 million Kelvin (3.6 million degrees Fahrenheit) getting sucked from the bottom of a solar prominence and spiral high into the corona. The solar tornado then developed for three hours, gases traveling in spiral paths for around 200,000 kilometers (120,000 miles).

"Prominences are tangled magnetic fields trapping cold and dense plasma in the solar corona," Xing Li, solar physicist at Aberystwyth University, told Discovery News. "These often erupt spectacularly and fly out into space as coronal mass ejections (CMEs), and large CMEs will impact our space weather and space technology in a significant way when they are heading toward the Earth.

"What drives these eruptions is still not clear and is very important to gain an understanding of CME initiation (so that we can possibly predict such events)."

As mankind becomes more dependent on sensitive technology, it is critical that we develop new and more sophisticated ways to predict the sun's next "temper tantrum." As it turns out, these twisted tornadoes may hold the key to predicting when the next CME will be launched.

"This unique and spectacular tornado must play a role in triggering global solar storms," said co-discoverer Huw Morgan, also at Aberystwyth University.

"These tornadoes may help to produce favorable conditions for CMEs to occur," Li added, pointing out that the tornadoes his team studied coincided with CME eruptions as observed by other instruments monitoring the wider corona.

Also, the tornadoes observed so far by Li and Morgan often occur at the root of where CMEs are initiated. As the dynamic structures wind-up magnetic fields and drag powerful electric currents high into the corona, these tornadoes could generate the conditions ripe for CME eruptions, they theorize.

But to observe the tornadoes in the first place requires a bit of luck.

Firstly, as they are magnetic structures, if the tornado is empty of radiating plasma, they will remain invisible. Only when hot plasma is being dragged high into the corona can they be seen. Conversely, should the tornado be completely flooded with plasma, you wouldn't see the motion of the material as the radiating plasma would be completely washed out.

Read more at Discovery News

Mar 28, 2012

Exploding Dinosaur Hypothesis Implodes

The pregnant ichthyosaur female from Holzmaden (Germany) that perished 182 million years ago puzzled researchers for quite some time: The skeleton of the extinct marine reptile is almost immaculately preserved and the fossilized bones of the mother animal lie largely in their anatomical position. The bones of the ichthyosaur embryos, however, are a different story: For the most part, they lie scattered outside the body of the mother. Such peculiar bone arrangements are repeatedly found in ichthyosaur skeletons. According to the broadly accepted scientific doctrine, this is the result of exploding carcasses: Putrefaction gases produced during the decomposition process cause the carcass to swell and burst. Through such explosions, even the bones of embryos can supposedly be ejected out of the body.

Based on an elaborate series of measurements and an analysis of the physical-biological parameters, however, a research team of sedimentologists, paleontologists and forensic scientists has now managed to dispel the myth of exploding dinosaur carcasses.

Putrefaction gas pressure not high enough

In order to gauge the pressure of the particular gases that can actually develop inside a putrefying ichthyosaur, the researchers sought comparative models and found one in human corpses: Humans and many ichthyosaur species have a similar size range. Consequently, the formation of similar amounts of putrefaction gas can be expected during decomposition. At the Institute of Forensic Medicine in Frankfurt, Germany, a manometer was inserted into the abdominal cavity through the umbilicus in one hundred corpses.The putrefaction gas pressures measured were only 0.035 bar. In the case of the ichthyosaur carcasses that came to rest below 50 to 150 meters of water, however, putrefaction gas pressures of over five to 15 bar would have been necessary to cause an explosion. According to Zurich paleontologist Christian Klug, gas pressures of this dimension and therefore actual explosions are impossible: "Large vertebrates that decompose cannot act as natural explosive charges." And he is convinced: "Our results can be extended to lung-breathing vertebrates in general."

What actually happened 182 million years ago

According to the researchers, the fate of ichthyosaur carcasses can be reconstructed as follows: Normally, the bodies sank to the seabed immediately post mortem. In very deep, hospitable waters, they were broken down completely through putrefaction,scavengers, bone-destroying organisms and dissolving processes. In shallower water (up to 50 meters) and a temperature of over four degrees Celsius, however, the corpses often rose back to the surface on account of the putrefaction gases accumulating inside the body. At the surface, exposed to the waves and scavengers, they decomposed within anything from a few days to weeks and the bones were scattered over a wide area on the seabed as they sank.

Read more at Science Daily

Odd Lipid out May Illuminate Evolution

Spectroscopic evidence for the unusual handedness of a mammalian lipid may advance our understanding of evolution.

Phospholipids are the main constituents of the cellular membranes in all organisms, ranging from single-celled archaea to highly complex plants and mammals. According to conventional wisdom, the chemical backbone of phospholipids in archaea is 'right-handed', but left-handed in all other organisms. The little-understood mammalian phospholipid bis(monoacylglycero)phosphate (BMP), however, is a possible exception to this rule. Peter Greimel, HuiHui Tan and their colleagues at the RIKEN Advanced Science Institute, Wako, have now obtained the first proof that BMP is indeed right-handed.

BMP is found only in mammals, and is a common -- but minor -- constituent of all animal tissues. The internal membranes of the waste treatment and recycling centers of cells -- so-called late endosomes and lysosomes -- have a higher proportion of BMP than any other animal membranes. This raised an intriguing question, explains Greimel: "How does BMP escape degradation inside these organelles, unlike all the other lipids and proteins?" This led to the [hypothesis] that BMP might actually be right-handed, allowing it to avoid attack by the organelle's digestive enzymes that are only capable of recognizing, and therefore destroying, left-handed lipids. All previous attempts to confirm the suspected unusual handedness -- or chirality -- of BMP had hit problems.

The research team first synthesized all the possible variations of BMP. They then reacted these variations with the chiral shift reagent D-camphor. "The D-camphor induced a change in the spectroscopic behavior of each synthetic BMP analogue," explains Greimel. This meant that the nuclear magnetic resonance (NMR) -- a common spectroscopic technique -- spectra of the BMP analogues were different enough to be distinguished from each other.

Next, the researchers isolated natural BMP from baby hamster kidney cells using standard techniques, then reacted it with D-camphor under very gentle conditions and analyzed it spectroscopically. They then compared the NMR spectra of the natural BMP derivative and the synthetic molecules. "Analysis of the spectroscopic data revealed that natural BMP is exclusively right-handed," Greimel says.

"Since BMP is right-handed, it means it most likely originated from the same common ancestor as archaea," he explains. The research team now plans to identify the enzymes involved in the biosynthesis of BMP, with the hope that detailed knowledge of this biosynthetic pathway will eventually lead to a better understanding of how life evolved on Earth.

Read more at Science Daily

Slow Swimming Shapes Unique Dolphin Society

The male dolphins of Shark Bay, Australia, are known to marine biologists for their messy social entanglements. Their relationships with each other are so unusual — they’re more like the intricate webs of the Mafia than the vertical hierarchies of chimpanzees — that, in a new paper, one team of scientists argues that the dolphins live in a social system that is “unique among mammals.” Intriguingly, the researchers also suggest that these complex, and often cooperative, relationships may stem in part from one simple, unexpected factor: the dolphins’ low cruising speed.

Mammals have evolved a variety of social structures. For example, chimpanzees live in what ethologists call “semiclosed groups”—that is, a community comprised of individuals who are well-known to each other. The members generally aren’t friendly to chimps in other communities; the males practice what’s known as community defense, patrolling and guarding their territory and fighting their neighbors. Inside that tight group, the chimpanzees also have male-male alliances.

At first glance, dolphins seem to have a somewhat similar social system. Two or three adult males form a tight alliance and cooperate to herd a female for mating. (Female dolphins rarely form strong alliances.) Other male teams may try to spirit away the female—particularly if she is in estrus. To fight back, the first-level alliances form partnerships with other first-level alliances, thus creating a larger second-level alliance. Some of these second-level alliances have as many as 14 dolphins and can last 15 years or more. On some occasions, the second-level alliance can call in the troops from yet another group, “a third-order alliance,” as the researchers call them—leading to huge battles with more than 20 dolphins biting and bashing each other with their heads and tails over the right to keep or steal a single female.

But are these dolphin battles analogous to what male chimpanzees do? That is, are the dolphin alliances also fighting over territory? To find out, a research team headed by Richard Connor, a cetacean biologist at the University of Massachusetts, Dartmouth, tracked 12 of the second-order alliances in Shark Bay—a 13,000-square-kilometer bay in western Australia—during the peak mating season from July to November over 6 years. The scientists monitored a 600-square-kilometer region of the bay, keeping tabs on every member in each alliance, the ranges, or areas, they regularly traveled, their behaviors, whether the males had a female with them, and—when there was a battle—which groups came to each other’s aid. Connor’s group then calculated the total home range for each alliance and mapped the degree of overlap between ranges.

The team discovered that, unlike chimps, none of the male groups were patrolling and defending a large community territory. Instead, the dolphins live in a society with a mosaic of many overlapping male and female ranges, without any apparent boundaries. “There isn’t a community border that males or females are patrolling,” says Connor, whose team reports its findings online March 28 in the Proceedings of the Royal Society B. Instead, he says, they live in an open society, with groups teaming up for a bit and splitting apart—all the while doing what Connor summarizes as “soap operatics,” trying to stay on top of who did what to whom, while deciding whether they should stay friends or become foes.

“It’s just unprecedented; there’s nothing like this in other mammal societies,” says Srđan Randić, the study’s lead author and Connor’s former graduate student, who is now a doctoral candidate at Paris University-South XI.

Although bonobos, orangutans, and Western gorillas have less hostile relationships with neighboring groups than do chimpanzees, none of these species has the tolerance of the dolphins, or their ability to form alliances outside of their immediate community. Among mammals, only elephants come close; though they live in matrilineal groups, elephants maintain relationships outside of these, forming large, stratified societies. But even these large societies are still primarily with close kin and are not changeable as are the dolphins’ alliances.

Because female dolphins give birth to only single calves that are separated by several years, the males cannot count on forming alliances with close kin. Instead, male dolphins must learn how to make and maintain friendships—demanding social skills that are likely to have contributed to the dolphins’ large brains, says Connor. But it’s not just the number of social relationships the dolphins must maintain, he adds. “It’s the uncertainty of those third-level alliances. It’s those guys you rarely see. What have they been up to since the last time you met them? Are they still on your side?”

Among mammals, humans, elephants, and dolphins are ranked highly by scientists for their level of social cognition—a convergence that Connor’s team suggests may be due in part to the minimal amount of energy these species expend when just cruising along. The dolphins, they add, offer a model for how a low cruising speed may lead to social smarts. Because the Shark Bay dolphin population is large and has overlapping territories, it doesn’t take long for one group of dolphins moving at their normal speed to meet up with another, possibly competitive, group. In those situations, the dolphins are forced to do the two things that scientists say enhance social cognition: make many friends and form group alliances. Or as Connor puts it, “If you’re going to run into your enemies, you better be with your friends, or have some that are close by, willing to be recruited.”

Read more at Wired Science

Billions of Habitable Worlds in Our Galaxy?

Take the most common type of star in the Milky Way -- so-called red dwarf stars that are cooler, smaller and longer-lived than stars like the sun.

Then, survey a sampling for orbiting planets and extrapolate the results. What do you get?

A stunning claim that 40 percent of our galaxy's 160 billion red dwarf stars have plus-sized Earths orbiting the right distance for liquid water to exist on their surfaces, a condition believed to be necessary for life.

If this finding is correct, that would mean the Milky Way is home to tens of billions of planets in habitable zones, concludes a team of scientists using an Earth-based telescope to look for planets beyond the solar system.

The effort is complementary to studies by NASA's Kepler space telescope, which hunts for extrasolar planets around sun-like stars.

About 80 percent of the stars in the Milky Way are red dwarfs, which, on average, are about one-third smaller and 4,000 degrees Fahrenheit cooler than the sun.

Kepler lead scientist William Borucki, with NASA's Ames Research Center in Mountain View, Calif., said he's not surprised by the finding of the European team, which uses a light-splitting spectrograph called HARPS on a telescope at the La Silla Observatory in Chile to look for planets beyond the solar system.

But claiming that red dwarfs' planets are rocky worlds goes too far, Borucki told Discovery News.

"I am astounded that they're saying they are rocky planets. I don't see any reason to assume they're rocky planets," Borucki said.

Limits of the technology used by the HARPS team, which looks for slight wobbles in starlight caused by an orbiting planet's gravity, make assessments of a planet's density difficult, if not impossible, to determine. The Kepler team, which finds planets as they pass across their parent star's face relative to the telescope's line of sight, likewise is limited by its technique.

"Each technique has some strengths and some real weaknesses. None of them is perfect. None of them give you all the answers you’d really like to have," Borucki said.

"If you put the two (techniques) together, then you can get size (of a planet) and the volume, and you get the density. If you know the density, you've got some idea of whether its rocky or not rocky," he added.

"They don't even have the mass, much less the size," Borucki said. "To say it's rocky I think is a real stretch."

The European team did determine that gas giant planets like Saturn and Jupiter are relatively rare around red dwarf stars, and that super-Earths -- planets a few times the diameter of Earth -- are common.

Read more at Discovery News

Cradle of Humanity Older Than Thought

The neighborhood you grew up in never quite looks the same when you go back. The ancestral neighborhood of all humanity in East Africa went through some changes too as plate tectonics pulled the Earth's crust apart and created the Rift Valley.

The geological shift around the old homestead may have started sooner than originally thought.

"We now believe that the western portion of the rift formed about 25 million years ago, and is approximately as old as the eastern part, instead of much younger as other studies have maintained,” said Michael Gottfried, a Michigan State University geologist, in a press release.

Gottfreid participated in a study that suggested the Rift Valley's two edges formed at around the same time, whereas earlier the eastern side was thought to be 15 to 25 million years older than the western side. Sediments from an ancient lake provided evidence that both halves formed about 25 million years ago.

“A key piece of evidence in this study is the discovery of approximately 25 million-year-old lake and river deposits in the Rukwa Rift that preserve abundant volcanic ash and vertebrate fossils,” said study leader Eric Roberts of Australia’s James Cook University in a press release.

The change in the Earth's crust would have resulted in altitude and weather pattern changes. That changing environment may have been part of what spurred apes to evolve into humans.

Read more at Discovery News

Mar 27, 2012

Stone Monolith Likely an Astronomical Marker

An ancient stone monolith in England was likely an astronomical marker, according to new archaeological evidence.

The 4,000-year-old stone is triangular in shape and angles up toward geographic south. Its orientation and slant angle are aligned with the altitude of the sun at midsummer, researchers said.

And new evidence shows that there are packing stones around the base of the 7.2-foot tall (2.2-meter) monolith, indicating that it was placed carefully in its location and position, they added.

"Given the sensitivity of the site, we can't probe under the surface of the soil," astronomer Daniel Brown of Nottingham Trent University in England said in a statement. "However, through our survey, we have found a higher density of packing stones on one side, supporting the case that the stone has been orientated intentionally."

The monolith is located at a ridge called Gardom's Edge in the Peak District National Park near Manchester, an area that shows evidence of human occupation extending far back though its history. Other ancient monuments such as Bronze Age roundhouses and a late Neolithic enclosure have been found nearby.

The seemingly astronomical monolith is thought to have been erected by Neolithic people around 2000 B.C.

"The stone would have been an ideal marker for a social arena for seasonal gatherings," Brown said. "It's not a sundial in the sense that people would have used it to determine an exact time. We think that it was set in position to give a symbolic meaning to its location, a bit like the way that some religious buildings are aligned in a specific direction for symbolic reasons."

The researchers used a 3D computer model to analyze how the stone would have been illuminated throughout the different seasons four millennia ago, given that the tilt of Earth's axis has changed over time.

Read more at Discovery News

Ancient Beluga Enjoyed Warmer Waters

An ancient beast related to today's Arctic-loving beluga whales and narwhals seemed to prefer toasty, tropical waters.

Called Bohaskaia monodontoides, the new species of toothed whale lived some 3 million to 4 million years ago during the Pliocene in warm water. Researchers aren't sure why modern belugas have left these tropical destinations and strayed pole-ward, where life would seem to be more difficult.

The fossil had been sitting in the collections of the Smithsonian's National Museum of Natural History since its discovery in a mine near Hampton, Va., in 1969. The nearly complete skull represents the only fossilized remains known of the new species. Before it was closely examined, the skull's discoverers loosely identified it as a beluga whale and left it in storage.

In 2010, Jorge Velez-Juarbe, Smithsonian pre-doctoral fellow from Howard University, finally took a close look at the skull. He compared it with the skulls of closely related toothed whales, like modern Arctic belugas and narwhals (also called unicorns of the sea for their twisted horn). While the skull shared many features, particularly in the face and snout, with modern toothed whales, the researchers say there are enough unique features to merit its placement in a new genus and species.

"We realized this skull was not something assignable to a beluga, and when we sat down, comparing the fossil side by side with the actual skulls of belugas and narwhals, we found it was a very different animal," study researcher Nicholas Pyenson, of the Smithsonian's National Museum of Natural History, said in a statement.

This and a second temperate example of a beluga-related whale indicate that the love of frosty water developed recently in these whales.

Read more at Discovery News

Most Ancient, 'Impossible' Alien Worlds Discovered

As we discover more worlds orbiting distant stars, we are finding that "conventional thinking" doesn't seem to apply to the growing menagerie of exoplanets. And this most recent exoplanetary discovery is no different.

In fact, the two exoplanets found to be orbiting a star 375 light-years away shouldn't exist at all.

The two gas giant planets were spotted during a survey of "metal poor" stars. When focusing on a star called HIP 11952, researchers from the Max-Planck Institute for Astronomy in Heidelberg, Germany, discovered a slight wobble in the star's position.

The wobble is being caused by the gravitational tug of two exoplanets -- one is nearly the size of Jupiter and orbits the star every seven days, the other is approximately three-times the size of Jupiter and has an orbital period of 290 days.

They're Metal Poor and Ancient

This may sound like a typical exoplanet discovery that uses the "radial velocity method" to detect the gravitational presence of planets around other stars, but this star isn't the kind of star one would expect to find planets at all.

HIP 11952 is a "metal-poor" star, which, in astrophysicist-speak, means this stellar example contains a very low abundance of elements heavier than hydrogen and helium. It turns out that metals are very important in the construction of planets, so metal-poor stars aren't exactly fertile places for planets to form.

"So far there are only very few planetary companions detected around stars with low stellar metallicity," said Johny Setiawan, astronomer who led this research at the Max-Planck Institute for Astronomy.

In the case of HIP 11952, the logarithm of the ratio of iron and hydrogen -- [Fe/H] -- is less than one.

"That means, the abundance of heavy elements, e.g., iron, is less than 10 percent compared to that of the sun," Setiawan told Discovery News.

This poses a very interesting question, and a conundrum.

So far, of the 750 confirmed exoplanet discoveries, there is a better statistical likelihood of a metal-rich star playing host to planets. And from our experience in the solar system, metals are obviously a very important component for planetary evolution. So, to find worlds orbiting a star with such a low metallicity seems to contradict this view.

But there's another thing. Metal-poor stars formed when the Universe was very young. The heavy elements that are ubiquitous throughout the cosmos today were formed inside the cores of generations of stars and when massive stars popped-off as supernovae. But the presence of metal-poor stars in the modern universe suggest they are very old.

In fact, it is thought HIP 11952 may be a surviving artifact of the dawn of the Universe -- it's nearly 13 billion years old. In other words, this star was born when the Universe was less than a billion years old. It is also thought to be a star from another, older galaxy -- the Milky Way probably acquired it during an ancient galactic collision.

As the star formed 13 billion years ago, it is likely that these two exoplanets (dubbed HIP 11952 b and HIP 11952 c) also formed around 13 billion years ago. These truly are cosmological oddities, they are the oldest exoplanets known.

It Depends On Your Definition

OK, so these worlds are really old and they shouldn't even exist, but as pointed out by Setiawan, it doesn't mean we need to re-write planetary formation theories.

"Of course, there is a problem in the definition of 'metal-rich' and 'metal-poor,'" he said. "HIP 11952 is from the point of view of the now universe 'metal-poor.' But in an epoch of the early universe (13 billion years ago) compared to other stars, HIP 11952 is extremely 'metal-rich.'

"At this age, stars normally have much lower metallicities. Heavy elements were created much later."

Read more at Discovery News

The Four Ages of the Universe -- What's Next?

The Greek poet Hesiod described the Five Ages of Man in mythology.

They progress from the Golden Age, when people lived among the gods, through the warlike Bronze Age and on to the Heroic Age. His narrative ends with the Iron Age, a period of toil and misery for mankind.

Science has now replaced these mythologies. We are at the point where we look at the entire universe as a grand series of game-changing leaps toward our emergence as an intelligent species. It is an epic story more compelling than anything from creation mythology.

In a recent paper, Marcelo Gleiser of Dartmouth College describes the universe’s first three ages as the physical age, chemical age, and biological age. He says that we are now entering the cognitive age, the emergence of intelligence life on Earth and presumably across the universe.

This leaves us with an enticing question: what will be the fifth age of the universe? Will this be a period of decline toward the burnout of the last star, as our extrapolations from current astrophysics predict? Or could it be something more existential and unpredictable given the potential influence of "thinking matter" on the arrow of time? Are we entering a cosmological Age of Aquarius?

Knowing Our Place in the Universe

Advances in astronomy over the past several decades allow us to precisely retrace the four ages of the universe to the present. We are the first generation to know the geometry, material composition, and evolution of the universe.

This has been largely accomplished by the discovery of the cosmic microwave background and large-scale telescopic surveys of the distribution of galaxies in space and time.

Within only the past 50 years we have learned that life as we know it relies on chemical elements forged in dying heavy stars. The first stars formed perhaps as early as 200 million years after the Big Bang. They forge the heavy elements in a fireworks finale of supernova explosions. We are confident that chemically-enriched second generation stars went on to build a plethora of stable planetary systems.

Some fraction of planets became astrobiological "Petri dishes" for biochemical reactions. The hallmark of the biological era is the still unknown leap from dormant matter to self-replicating matter. This remarkable process is driven by complex molecular nanomachines storing and reprocessing information under Darwinian rules.

But is Gleiser's cognitive era isolated to Earth? It presumes intelligent life could be co-emerging among the myriad stars and galaxies. At present it's probably simplest to say that the vast gulf of time and space keeps us in cosmic isolation, if not quarantine, from fully answering this question.

This leads me to the idea of a fifth age for the universe, yet to be realized. Perhaps intelligent entities can evolve to have mastery over entire galaxies, as predicted by the Soviet Russian astronomer Nikolai Kardashev in 1964. He imagined that through extraordinary astroengineering projects, far advanced aliens might reshape a galaxy to their liking. They may tap energy off the galaxy's central black hole and construct artificial habitats free of destruction from cosmic catastrophes.

Read more at Discovery News

Mar 26, 2012

Some Gulf Dolphins Severely Ill After Gulf Oil Spill

Bottlenose dolphins in Barataria Bay, Louisiana, are showing signs of severe ill health, according to NOAA marine mammal biologists and their local, state, federal and other research partners.

Barataria Bay, located in the northern Gulf of Mexico, received heavy and prolonged exposure to oil during the Deepwater Horizon oil spill.

Based on comprehensive physicals of 32 live dolphins from Barataria Bay in the summer of 2011, preliminary results show that many of the dolphins in the study are underweight, anemic, have low blood sugar and/or some symptoms of liver and lung disease. Nearly half also have abnormally low levels of the hormones that help with stress response, metabolism and immune function.

Researchers fear that some of the study dolphins are in such poor health that they will not survive. One of these dolphins, which was last observed and studied in late 2011, was found dead in January 2012.

Investigation of Dolphin Strandings in the Northern Gulf Continues

Since February 2010, more than 675 dolphins have stranded in the northern Gulf of Mexico (Franklin County, Florida, to the Louisiana/Texas border)-a much higher rate than the usual average of 74 dolphins per year, prompting NOAA to declare an Unusual Mortality Event (UME) and investigate the cause of death for as many of the dolphins as possible. The vast majority of stranded dolphins have been found dead; however, 33 have stranded alive and seven have been taken to facilities for rehabilitation.

In the spring, it is typical to see some newborn, fetal and stillborn dolphins strand, and there has been an increase in strandings of this younger age class during this UME in 2010 and 2011. Yet all age classes continue to strand at high levels. NOAA is working with a team of marine mammal health experts to investigate the factors that may be contributing to the dolphin mortalities.

Gulf Seafood Safety Since the 2010 oil spill, the Food and Drug Administration, NOAA and the Gulf Coast states have used an agreed-upon protocol to test seafood and ensure that it is free of harmful oil and dispersant residues. NOAA opened federal waters to fishing after extensive testing, and the Gulf states continue to use the protocol to routinely test finfish and shellfish to ensure all seafood reaching the consumer is safe. Some waters in the northern Barataria Basin, a larger area that includes Barataria Bay, remain closed to commercial fishing, as visible oil is still present along the shoreline where the closures are in place. The joint protocol directs seafood safety testing to begin only after visible oil is gone.

Read more at Science Daily

Hammerhead Shark Double Whammy

Identity confusion between a new, yet unnamed shark species, originally discovered off the eastern United States by Nova Southeastern University Oceanographic Center (NSU-OC) researchers, and its look-alike cousin -- the endangered scalloped hammerhead shark -- may threaten the survival of both species.

According to an April 2012 article in the scientific journal Marine Biology, the new look-alike hammerhead species has now been discovered more than 4,300 miles away near the coast of southern Brazil. This confirms that the original finding was not a local oddity and the new species is much wider spread. The look-alike species may face the same fishery pressures as the real scalloped hammerhead, which is being fished unsustainably for its highly prized fins.

"It's a classic case of long-standing species misidentification that not only casts further uncertainty on the status of the real scalloped hammerhead but also raises concerns about the population status of this new species," says professor Mahmood Shivji, Ph.D., who oversaw the new research at the NSU-OC's Save Our Seas Shark Center USA and Guy Harvey Research Institute.

Tens of millions of sharks are being killed for their fins and meat worldwide, resulting in dramatic reductions in shark populations and concerns about the broad scale negative impacts to ocean ecosystems. This has prompted international protection and other management efforts to reduce the unsustainable slaughter of sharks.

"It's very important to officially recognize, name and learn more about this new hammerhead species and the condition of its populations through systematic surveys," Shivji says. "Without management intervention to curtail its inadvertent killing, we run the risk that overfishing could eradicate an entire shark species before its existence is even properly acknowledged."

Shivji's team first discovered the new hammerhead species in 2005 when examining the DNA of sharks thought to be scalloped hammerheads based on their physical appearance. A research team from the University of South Carolina independently confirmed the existence of the new species in 2006.

Combining genetic assessments of NSU and South Carolina researchers shows that at least 7 percent of the sharks in U.S. waters originally thought to be scalloped hammerheads turned out to be the new species. This means that the population of the endangered real scalloped hammerhead in U.S. waters is probably smaller than originally thought.

The status of the scalloped hammerhead (Sphyrna lewini) is currently under review by the U.S. National Marine Fisheries Service to determine if it warrants listing as threatened or endangered under the U.S. Endangered Species Act. It's already on the red list of endangered species of the International Union for Conservation of Nature and Natural Resources (IUCN). The new species is on neither list.

"We hope that during this important scalloped hammerhead status review, the new look-alike species will be recognized, and possible impacts of historical mix-ups between the two species on past scalloped hammerhead stock assessments will be considered," says Shivji.

According to Danillo Pinhal, Ph.D., an assistant professor at the UNESP-São Paulo State University in Brazil who performed the lab work as a visiting graduate student in Shivji's laboratory in 2009, "the finding of this species all the way down in Brazilian waters, where hammerhead sharks are heavily fished, raises concerns about the population status of both species not just in U.S. waters but throughout the western Atlantic. It's an international issue now and it's essential that further research on this new species be conducted in Brazilian waters."

Other than differences in their DNA, the two shark species also differ in their number of vertebrae. The new look-alike species has approximately 20 fewer vertebrae than the scalloped hammerhead, in the range of 170 vs. 190. An analysis of the DNA suggests that the new species and the scalloped hammerhead separated from each other approximately 4.5 million years ago, a surprisingly long time given how similar they look externally.

There are three well-documented species of large hammerhead sharks (scalloped, great and smooth hammerheads), and their fins have high value in the international shark fin trade. The finding of this new hammerhead now brings the total to four large species with this unique hammerhead shape.

Read more at Science Daily

Moon's Creation Questioned by Chemistry

New questions have been raised about the birth of the moon after a new study found samples from Earth and the lunar surface to be virtually identical.

The study reported in the journal Nature Geoscience contradicts the theory that the moon formed after the impact of a Mars-sized object named Theia with the early Earth about 4.5 billion years ago.

At the time both the Earth and Theia were still partially molten, the impact causing Theia's core to sink into the Earth's core, while lighter ejecta and debris was thrown into space eventually coalescing to form the moon.

The new study by Junjun Zhang, of the University of Chicago, and colleagues compared isotopic ratios of titanium in lunar and terrestrial samples.

Zhang and colleagues found the ratio of titanium isotopes on both Earth and the moon to be identical to within about four parts per million.

Because the Mars-sized impactor is expected to have been isotopically different, the measurements suggest the moon is either made entirely of material from Earth, or intense mixing occurred on both bodies after impact.

Zhang and colleagues say the similarity can't be explained by both bodies forming in the same part of the solar system because meteorite samples show extensive diversity in titanium isotopic ratios.

They conclude the isotopes are far more likely to have come from Earth rather than another planet.

Planetary scientist Brad Carter from the University of Southern Queensland says while it's unlikely to have two planets with the same chemical composition, it's not impossible.

"Despite what the paper says, a planet forming very close to the early Earth could have a similar composition resulting in similar isotopic ratios," says Carter.

"It's also possible that Theia was essentially made of ice, something from the Kuiper belt in the outer solar system."

"This would have provided the energy of impact, but with the ice evaporating away leaving Earth material to eject into space and form the moon."

Another option suggested by Zhang and colleagues involved the proto-Earth spinning much faster than previously thought, allowing a greater degree of mixing.

"However we don't really think Earth had spun rapidly enough for that to happen," says Carter.

"And then you have the problem of slowing down the Earth's rotation afterwards."

"Zhang and colleagues suggest a gravitational resonance effect between the Earth, moon and sun may have provided the forces needed to slow down the Earth's spin rate," says Carter.

Read more at Discovery News

Venice Sinking More Than Previously Thought

Venice has begun sinking again and is even tilting slightly eastward, new satellite measurements have revealed.

Despite previous studies suggesting the subsidence had levelled off, new research indicates that the lagoon city continues to sink an average of one to two millimeters (0.04 to 0.08 inches) a year.  That's more than researchers previously thought.

"It’s a small effect, but it’s important," Yehuda Bock, a research geodesist with Scripps Institution of Oceanography at the University of California, San Diego, in La Jolla, Calif., said.

With the Adriatic rising in the Venetian lagoon at the same rate, the combined effect is a 4mm (0.16 inches) a year increase in sea level. This means that Venice could sink up to 80 mm (3.2 inches) by 2032.

The study, which will be published March 28 in Geochemistry, Geophysics, Geosystems, a journal of the American Geophysical Union, also found that the City of Water in north-east Italy is listing one millimeter or two (0.04 to 0.08 inches) eastward per year, meaning that the western part is higher than the listing one millimeter or two (0.04 to 0.08 inches) eastward per year, meaning that the western part is higher than the rest.

Prior satellite analyses didn’t pick up on the tilt, Bock said.

Bock worked on the project with colleagues from the University of Miami in Florida and Italy's Tele-Rilevamento Europa, a company that specialises in the measurement of ground deformations.

The team used a combination of GPS and and satellite radar to map how Venice and its lagoon were drifting over the decade between 2000 and 2010.

"Our analysis clearly captured the movements over the last decade that neither GPS nor InSAR could sense alone," said Shimon Wdowinski, associate research professor of Marine Geology and Geophysics at the University of Miami.

The subsidence was confirmed by the slow sinking of Venice's 117 islands, with those in the north dropping at a rate of two to three millimeters (0.08 to 0.12 inches) per year, and those in the south subsiding at three to four millimeters (0.12 to 0.16 inches) per year.

Venice’s subsidence is well known. Precise measurements of the city's sea level date only to 1872, but 18th-century Venetian landscapes by the artist Canaletto, so true to detail to portray the dark algae stains left on canal-side buildings by retreating high tides, allowed scientists to determine that the city  has sunk more than 60 centimeters (2 feet) since 1727.

The frequency of floods in Venice is now increasing, and about four or five times a year residents have to walk on wooden planks to stay above the floodwaters in large parts of the city.

According to the researchers, builders of the ambitious multi-billion euro MOSE flood-protection system, which is set for completion in 2014, will have to take into consideration "not only the rising of sea level, but also the subsidence," they said.

However, researchers in Italy estimate that a subsidence of one-two millimeter per year is not a significant drop.

"One millimeter is nothing with respect to the problem that Venice experienced 20, 30 years ago," said Pietro Teatini, a researcher with the University of Padova in Italy.

Indeed, Venice subsided about 120 mm ( 4.72 inches) in the 20th century due to natural process and groundwater extraction, plus saw a sea level rise of about 110 mm (4.33 inches) at the same time.

Luigi Tosi, a geologist at Italy's Institute of Marine Science - National Research Council, agrees that the lagoon city has to face "a complex future" in which the MOSE's adjustable barriers will have to be used very often.

According to Tosi, the sea rising, which could reach 50 centimeters (19.68 inches) by the end of the century, could be a significant problem.

Read more at Discovery News

Mar 25, 2012

Monster Hailstone Drops On Hawaii

A grapefruit-size hailstone that pummeled Oahu during a hailstorm this month has now been confirmed as the largest on record for the state of Hawaii, announced officials with the National Oceanic and Atmospheric Administration (NOAA).

A final measurement of the hailstone, which dropped from the skies on March 9, places it at 4.25 inches long, 2.25 inches tall and 2 inches wide (10.8 by 5.7 by 5 centimeters).

"According to hail report records for Hawaii kept back to 1950, the previous state record hailstone was 1 inch in diameter," Michael Cantin, warning coordination meteorologist at NOAA's National Weather Service (NWS) in Honolulu, said in a statement. The NWS, along with NOAA's State Climate Extremes Committee confirmed the new state record.

The record-setting hailstone was dropped by a so-called supercell thunderstorm on the windward side of Oahu that also produced large hail in Kaneohe and Kailua. Perhaps the most violent of all thunderstorm types, supercell thunderstorms can generate damaging winds large hail, and even tornadoes, according to NOAA. They are most common during the spring across the central United States.

NOAA received several reports of hail with diameters of 2 to 3 in. (5 to 7.6 cm) and greater in Hawaii during the storm. One such report, the new record breaker, came from a resident in the Aikahi neighborhood of Kailua, who reported a hailstone larger than 3 inches in diameter. Inspection by the NWS revealed the chunk was much larger, and has now been confirmed the largest on record.

In fact, since records began, there have been no reports of hail larger than an inch in diameter; penny-size (just under an inch) or quarter-size (1 inch in diameter) hailstones, have been reported just eight times in Hawaii. Conditions needed to produce supercell thunderstorms, and thus to form large hailstones, the size of golf balls and baseballs, are rare in Hawaii.

To form, supercells need warm, most air to rise, forming progressively colder and drier air; at the same time, winds that change direction and increase in speed with increasing height off the ground are needed. Both sets of conditions existed on March 9, an ideal day for a supercell storm, it seems.

Read more at Discovery News

Thousands of Atheists Rally in D.C.

Thousands of atheists, agnostics and other non-believers turned out in the US capital on Saturday to celebrate their rejection of the idea of God and to claim a bigger place in public life.

The Reason Rally, sponsored by 20 atheist, secular and humanist groups, was billed as the biggest-ever "coming-out" party for the fastest-growing religious group in the United States -- those with no religion.

"There are too many people in this country who have been cowed into fear of coming out as atheists, secularists or agnostics," said the event's star turn, Richard Dawkins, the British scientist and best-selling atheist author.

"We are far more numerous than anybody realizes," he said, prompting a loud cheer from the youthful crowd that defied gray skies and drizzle for an afternoon of speeches, music and satire on the National Mall.

Jesse Galef of the Secular Student Alliance, a spokesman for the rally, told AFP he conservatively estimated the turnout at 10,000. The National Park Service, which oversees the mall, had issued a permit for 15,000.

In the center of the good-humored crowd rose a crucifix with an affixed sign that declared: "Banish the Ten Commandments to the dustbin of history." Other posters read: "Good without a god" and "Hi Mom! I'm an atheist."

"This country was not built on religion and God," said another of the day's speaker, Michael Shermer, a self-defined "skeptic" and columnist for the respected Scientific American magazine. "It was built on reason."

"God fixation won't fix our nation, because nothing fails like prayer," added Annie Laurie Gaylor of the Freedom From Religion Foundation, which is contesting Pennsylvania's declaration of 2012 as "the year of the Bible."

On the edges of the Mall, atheists engaged in vigorous debates with a handful of Christians who turned up with their own placards that read: "Study and obey the Bible" and "Jesus forgives sin."

"Jesus Christ is your only hope," exclaimed one soapbox preacher through a bullhorn. "Humble yourself today."

In no other Western country does religion figure so highly in society as in the United States, where "In God We Trust" appears on bank notes and "one nation under God" is part of the national Pledge of Allegiance.

Yet the most recent American Religious Identification Survey, published in 2009, found that Americans with no religious affiliations -- "the nones" in sociological jargon -- make up 15 percent of the total adult population.

"That is more than Jews, Muslims, Hindus and Buddhists combined and doubled," said David Silverman, president of American Atheists, which campaigns for the civil rights of non-believers.

David Roozen of the Hartford Institute for Religion Research in Connecticut said the number of Americans with no religious affiliation has "about doubled" in the last 20 years.

"It's probably the fastest-growing category of religion in the United States," the sociologist told AFP in a telephone interview earlier this week.

Silverman, who defines atheism simply as "the lack of belief in a god," said a deep-seated fear of prejudice and discrimination leads many Americans with no religious affiliation not to acknowledge themselves as atheists.

Read more at Discovery News