May 18, 2013

Watch the Biggest Explosion Ever Seen on the Moon

NASA scientists recorded the biggest explosion from a meteorite impact seen on the moon in eight years of monitoring.

The lunar burst was caused by a 40-kilogram boulder-sized rock slamming into the surface at about 90,000 kph. It generated a flash 10 times brighter than anything seen before, which came from the thermal glow of molten rock at the point of impact.

The moon, like most bodies in the solar system, is subject to relatively frequent bombardment by small space rocks. Most of these objects are fairly tiny, pebble-sized or smaller, but in 2005 NASA set up a specific program to identify how often they occur. The lunar impact team has since identified more than 300 explosions, most of them faint and usually happening at the same time as a meteor shower on Earth. Researchers want to know how often they can expect such impacts, which could come in handy when planning moonwalks during future astronaut trips to our satellite.

The March 17 impact created a blast that was bright enough to be seen from Earth with the naked eye. It may have generated a crater roughly 20 meters wide, which could be imaged by the Lunar Reconnaissance Orbiter next time it passes over the area, allowing researchers to see a very fresh impact on the moon.

From Wired Science

How science takes the Bible to bits

Steve Jones's scientific retelling of the Bible in The Serpent's Promise is lively and amusing, but it is hard to tell what audience the book is intended for

Where does the idea of a single soul at conception leave twins?
THE Bible has been called "the greatest story ever told". Steve Jones begs to differ. In The Serpent's Promise, Jones, a British geneticist and outspoken anti-religionist, sets out to retell the Bible from the point of view of science.

Well, not exactly. Instead of a point-by-point fact-checking of the Christian holy book, Jones has opted to pick some of its main themes. From big topics such as the origins of the world and of humans, Noah's flood and other epic disasters, and the ultimate fate of Earth, he sketches out our scientific knowledge for each.

Sometimes this works well. The chapter on origins, for example, takes a quick tour through the big bang, the formation of Earth, the history of the continents, the origin of life, its evolutionary history, plus human evolution – and all in less than 40 pages.

Needless to say, Jones is aiming to hit the high points, not provide a comprehensive lesson. But it all hangs together, and it gives a fair overview of science's alternative to the first chapters of Genesis.

At other times, though, this approach seems to be little more than an excuse for rambling. For instance, the Bible pays a huge amount of attention to matters of reproduction: think of all the "begats", not to mention the virgin birth of Jesus. Jones takes this as a pretext to launch into a discussion of reproductive biology that wanders from sea urchin embryology and why there are two sexes, to sperm donation and genetic imprinting. By the time we get to the end of the chapter, we have strayed a long way from any remotely biblical topic.

Much of the book is like this – a collection of random walks from biblical starting points – and it leaves the reader feeling rather adrift. That is a shame, because, paragraph by paragraph, Jones is always lively and often wickedly funny. He notes, for example, that vicars and insurance sellers are in the same game – of convincing people to forgo immediate pleasures for long-term security.

To those who believe that humans are endowed with a soul from the moment of conception, he points out that his mother was an identical twin formed when a fertilised egg accidentally split into two separate embryos. What happened to the single soul when it found itself with two bodies? "Were my mother and her sister, my Aunt Pegi, blessed with just half a copy each," he asks, "or does God have a stock of spares ready to insert when needed?" Whatever the book's other faults, Jones is never boring.

But he can be hasty and careless. At one point he says that the pre-Columbian New World was sparsely populated by small, scattered bands; five pages on he says that large parts of South America were heavily settled and "buzzed with activity". Elsewhere, he writes that HIV is an exclusively human virus, but four pages later that it also infects chimps. Then there are the many unclear pronouns that sometimes leave us unsure as to the precise meaning of sentences. For example, when Jones writes about the first multi-drug-resistant plasmid – a transmissible ring of DNA – emerging in a strain of plague in Madagascar, he muddies the water with unclear uses of "it". If this book passed through an editor's hands, he or she left few prints. In a perfect world, authors would be perfect, but in the real world, we need editors to pick up the errors.

A bigger problem, though, is that Jones seems unclear who his audience is. He oversimplifies some concepts and goes into dizzying detail on others. The book skims too lightly over the surface to interest most science enthusiasts, and religious readers are likely to be put off by the barbed comments.

Read more at New Scientist

May 17, 2013

World's Smallest Liquid Droplets Ever Made in the Lab, Experiment Suggests

Physicists may have created the smallest drops of liquid ever made in the lab.

That possibility has been raised by the results of a recent experiment conducted by Vanderbilt physicist Julia Velkovska and her colleagues at the Large Hadron Collider, the world's largest and most powerful particle collider located at the European Laboratory for Nuclear and Particle Physics (CERN) in Switzerland. Evidence of the minuscule droplets was extracted from the results of colliding protons with lead ions at velocities approaching the speed of light.

According to the scientists' calculations, these short-lived droplets are the size of three to five protons. To provide a sense of scale, that is about one-100,000th the size of a hydrogen atom or one-100,000,000th the size of a virus.

"With this discovery, we seem to be seeing the very origin of collective behavior," said Velkovska, professor of physics at Vanderbilt who serves as a co-convener of the heavy ion program of the CMS detector, the LHC instrument that made the unexpected discovery. "Regardless of the material that we are using, collisions have to be violent enough to produce about 50 sub-atomic particles before we begin to see collective, flow-like behavior."

These tiny droplets "flow" in a manner similar to the behavior of the quark-gluon plasma, a state of matter that is a mixture of the sub-atomic particles that makes up protons and neutrons and only exists at extreme temperatures and densities. Cosmologists propose that the entire universe once consisted of this strongly interacting elixir for fractions of a second after the Big Bang when conditions were dramatically hotter and denser than they are today. Now that the universe has spent billions of years expanding and cooling, the only way scientists can reproduce this primordial plasma is to bang atomic nuclei together with tremendous energy.

The new observations are contained in a paper submitted by the CMS collaboration to the journal Physical Review D and posted on the arXiv preprint server. In addition, Vanderbilt doctoral student Shengquan Tuo recently presented the new results at a workshop held in the European Centre for Theoretical Studies in Nuclear Physics and Related Areas in Trento, Italy.

Scientists have been trying to recreate the quark-gluon plasma since the early 2000s by colliding gold nuclei using the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. This exotic state of matter is created when nuclei collide and dump a fraction of their energy into the space between them. When enough energy is released, it causes some of the quarks and gluons in the colliding particles to melt together to form the plasma. The RHIC scientists had expected the plasma to behave like a gas, but were surprised to discover that it acts like a liquid instead.

When the LHC started up, the scientists moved to the more powerful machine where they basically duplicated the results they got at RHIC by colliding lead nuclei.

In what was supposed to be a control run to check the validity of their lead-lead results, the scientists scheduled the collider to smash protons and lead nuclei together. They didn't expect to see any evidence of the plasma. Because the protons are so much lighter than lead nuclei (they have only one-208th the mass), it was generally agreed that proton-lead collisions couldn't release enough energy to produce the rare state of matter.

"The proton-lead collisions are something like shooting a bullet through an apple while lead-lead collisions are more like smashing two apples together: A lot more energy is released in the latter," said Velkovska.

Last September, the LHC did a brief test run to make sure it was adjusted properly to handle proton-lead collisions. When the results of the run were analyzed, team members were surprised to see evidence of collective behavior in five percent of the collisions -- those that were the most violent. In these cases, it appeared that when the "bullet" passed through "apple" it released enough energy to melt some of the particles surrounding the bullet hole. They appeared to be forming liquid droplets about one tenth the size of those produced by the lead-lead or gold-gold collisions.

However, the initial analysis was limited to tracking the motion of pairs of particles. The researchers knew that this analysis could be influenced by another well-known phenomenon, the production of particle jets. So, when the scheduled proton-lead run took place in January and February, they searched the data for evidence of groups of four particles that exhibit collective motion. After analyzing several billion events, they found hundreds of cases where the collisions produced more than 300 particles flowing together.

Read more at Science Daily

First Ever Underwater University Lectures

Students at the University of Essex have taken their lectures to a whole new level -- 18 metres under the sea in remote Indonesia to be precise.

The ground-breaking underwater marine biology lectures were the first of their kind, adding to the teaching, educational and learning experience during dives on tropical coral reef systems.

The lectures were held during the annual field trip to the Wakatobi Marine National Park in Indonesia, organised by the University's School of Biological Sciences for its students.

The serious challenges threatening the future of the world's coral reefs are the backbone of major research being carried out by the University's internationally-recognised Coral Reef Research Unit (CRRU). Its on-going research, focused in this area of Indonesia, looks at the impact of climate change on coral reefs and how to work with nature to find a solution. More than half a billion people depend on coral reefs for food and income.

For the underwater lectures, Professor David Smith used specialised audio equipment so he could talk to students underwater, explaining exactly what they were seeing as they were seeing it. This was a world away from usual underwater communication involving basic slates to write on and hand signals.

"It was a fantastic experience as I was able to use the power of observation like never before," explained Professor Smith. "I have been on thousands of dives over the years but this was a totally new experience as I was able to explain to students exactly what they were seeing and inject more passion and feeling into the whole lecture. It was very special and transformed the whole experience both for me and our students."

Using a University of Essex special teaching grant, Professor Smith was able to buy an audio system which, to date, has never been used for formal lecturing and is only used by TV presenters and some professional divers. Professor Smith wore a full face mask which included a microphone and the students wore headsets so they could hear him talk. A hydrophone -- an underwater microphone − was then positioned in the water which was linked to a control box and recorder on a boat.

With over 1,000 videos taken during the underwater lectures, adding up to 15 hours of footage, these will prove to be a valuable virtual field course resource for students who are not able to travel to Indonesia but can still get an insight into the experience whilst also providing a great "listen again" opportunity for participating students.

Second-year marine and freshwater biology student Tilly James said: "The underwater lectures were an invaluable part of the course as they enabled us to get a much better understanding of how all the components of the reef system were interacting with each other.

Read more at Science Daily

Victorian Era Brits Were Smarter Than Us

The average intelligence level of Victorian Era individuals was higher than that of people today, according to a new study.

We’re not all dumb, however, as another study in the same journal, Intelligence, found that intelligence has steadily increased in Saudi Arabia over the past four decades.

Why study these parts of the world in the first place? For the new study on Victorians vs. us, lead author Michael Woodley of Umea University in Sweden and colleagues Jan te Nijenhuis and Raegan Murphy offered the following:

“The Victorian Era was marked by an explosion of innovation and genius, per capita rates of which appear to have declined subsequently. The presence of dysgenic fertility for IQ amongst Western nations, starting in the 19th century, suggests that these trends might be related to declining IQ. This is because high-IQ people are more productive and more creative. We tested the hypothesis that the Victorians were cleverer than modern populations, using high-quality instruments, namely measures of simple visual reaction time in a meta-analytic study.”

The latter refers to reaction times to visual stimuli (called RT), which were measured in tests administered to people from the late 1800’s until 2004. The researchers couldn’t compare standard IQ tests because those have changed over the years.

The RT tests supposedly can reflect a person’s IQ. The faster the person reacts, the smarter he or she supposedly is.

Intelligence as we think of it today, though, is very complex, encompassing hard-to-measure traits like creativity, ability to reason, communication skills and more. A person’s thinking ability can also be influenced in the moment by nutrition, amount of sleep, distractions, stress and other factors.

Nevertheless, the researchers posit that RT can indicate the inherent intelligence of a person, likely referring to that individual’s genetically inherited brainpower. This is therefore not affected by things like education level, environmental influences and individual health.

At any rate, the study found that RT rates have dramatically increased over time, basically meaning people are becoming mentally more slow and stupid. Men went from 183 ms in the Victorian Era to 253 ms in modern times. Women went from 188 ms to 261ms.

Read more at Discovery News

Venus, Jupiter and Mercury Will Dance on May 28

Understanding events in the night sky is much like enjoying a cup of coffee in your favorite coffee shop!

For example, right now, a delicious 'grande' mug of decaf skinny peppermint latte (it's really good, you should try it) is sitting a foot or two behind my screen. From where I am sitting, the screen and cup appear to be right next to each other, yet I know that they are separated by some distance.

This is a great analogy for the many planetary alignments, or conjunctions, we can enjoy in the night sky. And one impressive one is coming on May 28 -- Venus, Jupiter and Mercury will seem to gracefully sweep past one another in a tight grouping in the sky, but in reality they are millions of kilometers apart.

I still find it amazing that we can predict such celestial events and even send spacecraft not to where a planet is right now, but where it will be in a few years time when the spacecraft arrives! Totally crazy.

One of the key developments in history that has given us this beautiful ability is the articulation of a set of laws that the planets seem to adhere to during their relentless journey around the sun.

It was Johannes Kepler who documented his three laws of planetary motion back in the first few decades of the 17th Century. The laws are all pretty self explanatory:

1. Planets move in elliptical orbits with the sun at one of the foci.

2. A line joining the sun to a planet -- the radius vector -- sweeps out equal areas of space at equal intervals of time (basically means planets travel faster nearer the sun and slower further away)

3. The square of the orbital period of a planet is proportional to the cube of its mean distance from the sun.

Using these laws, which fundamentally come from the laws of gravitation, allows us to predict with incredible accuracy how the planets move so we can tell that on May 28th, 2013, Venus and Jupiter will pass within one degree of one other (about twice the apparent size of the full moon). To add a little bit of sparkle, a little further above the horizon Mercury will put in an appearance.

Although they may look close from our point of view, in reality Jupiter will be 660 million kilometers further away than Venus, and 744 million kilometers further away than Mercury, which is the closest of all of them come to us. Mercury is always an elusive planet but the 28th will be a great evening to try and spot it low in the west after sunset.

Read more at Discovery News

May 16, 2013

Weather On the Outer Planets Only Goes So Deep

What is the long-range weather forecast for the giant planets Uranus and Neptune? These planets are home to extreme winds blowing at speeds of over 1000 km/hour, hurricane-like storms as large around as Earth, immense weather systems that last for years and fast-flowing jet streams. Both planets feature similar climates, despite the fact that Uranus is tipped on its side with the pole facing the sun during winter. The winds on these planets have been observed on their outer surfaces; but to get a grasp of their weather systems, we need to have an idea of what is going on underneath. For instance, do the atmospheric patterns arise from deep down in the planet, or are they confined to shallower processes nearer the surface?

New research at the Weizmann Institute of Science, the University of Arizona and Tel Aviv University, which was published online today in Nature, shows that the wind patterns seen on the surface can extend only so far down on these two worlds.

Understanding the atmospheric circulation is not simple for a planet without a solid surface, where Earth-style boundaries between solid, liquid and gas layers do not exist. Since the discovery of these strong atmospheric winds in the 1980s by the Voyager II spacecraft, the vertical extent of these winds has been a major puzzle -- one that influences our understanding of the physics governing the atmospheric dynamics and internal structure of these planets. But a team led by Dr. Yohai Kaspi of the Weizmann Institute's Environmental Sciences and Energy Research Department realized they had a way, based on a novel method for analyzing the gravitational field of the planets, to determine an upper limit for the thickness of the atmospheric layer.

Deviations in the distribution of mass in planets cause measurable fluctuations in the gravitational field. On Earth, for example, an airplane flying near a large mountain feels the slight extra gravitational pull of that mountain. Like Earth, the giant planets of the solar system are rapidly rotating bodies. In fact all of them rotate faster than Earth; the rotation periods of Uranus and Neptune are about 17 and 16 hours, respectively. Because of this rapid rotation, the winds swirl around regions of high and low pressure. (In a non-rotating body, flow would be from high to low pressure.) This enables researchers to deduce the relations between the distribution of pressure and density, and the planets' wind field. These physical principles enabled Kaspi and his co-authors to calculate, for the first time, the gravity signature of the wind patterns and thus create a wind-induced gravity map of these planets.

By computing the gravitational fields of a large range of ideal planet models -- ones with no wind, a task conducted by team member Dr. Ravit Helled of Tel Aviv University -- and comparing them with the observed gravitational fields, upper limits to the meteorological contribution to the gravitational fields were obtained. This enabled Kaspi's team, which included Profs. Adam Showman and Bill Hubbard of the University of Arizona, and Prof. Oded Aharonson of the Weizmann Institute, to show that the streams of gas observed in the atmosphere are limited to a "weather-layer" of no more than about 1000 km in depth, which makes up only a fraction of a percent of the mass of these planets.

Although no spacecraft missions to Uranus and Neptune are planned for the near future, Kaspi anticipates that the team's findings will be useful in the analysis of another set of atmospheric circulation patterns that will be closely observed soon: those of Jupiter. Kaspi, Helled and Hubbard are part of the science team of NASA's Juno spacecraft to Jupiter. Juno was launched in 2011; upon reaching Jupiter in 2016 it will provide very accurate measurements of the gravity field of this giant gaseous planet. Using the same methods as the present study, Kaspi anticipates that they will be able to obtain the same type of information they acquired for Uranus and Neptune: namely, placing constraints on the depth of the atmospheric dynamics of this planet.

Read more at Science Daily

World's Melting Glaciers Making Large Contribution to Sea Rise

While 99 percent of Earth's land ice is locked up in the Greenland and Antarctic ice sheets, the remaining ice in the world's glaciers contributed just as much to sea rise as the two ice sheets combined from 2003 to 2009, says a new study led by Clark University and involving the University Colorado Boulder.

The new research found that all glacial regions lost mass from 2003 to 2009, with the biggest ice losses occurring in Arctic Canada, Alaska, coastal Greenland, the southern Andes and the Himalayas. The glaciers outside of the Greenland and Antarctic sheets lost an average of roughly 260 billion metric tons of ice annually during the study period, causing the oceans to rise 0.03 inches, or about 0.7 millimeters per year.

The study compared traditional ground measurements to satellite data from NASA's Ice, Cloud and Land Elevation Satellite, or ICESat, and the Gravity Recovery and Climate Experiment, or GRACE, missions to estimate ice loss for glaciers in all regions of the planet.

"For the first time, we've been able to very precisely constrain how much these glaciers as a whole are contributing to sea rise," said geography Assistant Professor Alex Gardner of Clark University in Worcester, Mass., lead study author. "These smaller ice bodies are currently losing about as much mass as the ice sheets."

A paper on the subject is being published in the May 17 issue of the journal Science.

"Because the global glacier ice mass is relatively small in comparison with the huge ice sheets covering Greenland and Antarctica, people tend to not worry about it," said CU-Boulder Professor Tad Pfeffer, a study co-author. "But it's like a little bucket with a huge hole in the bottom: it may not last for very long, just a century or two, but while there's ice in those glaciers, it's a major contributor to sea level rise," said Pfeffer, a glaciologist at CU-Boulder's Institute of Arctic and Alpine Research

ICESat, which ceased operations in 2009, measured glacier changes using laser altimetry, which bounces laser pulses off the ice surface to determine changes in the height of ice cover. The GRACE satellite system, still operational, detects variations in Earth's gravity field resulting from changes in the planet's mass distribution, including ice displacements.

GRACE does not have a fine enough resolution and ICESat does not have sufficient sampling density to study small glaciers, but mass change estimates by the two satellite systems for large glaciated regions agree well, the scientists concluded.

"Because the two satellite techniques, ICESat and GRACE, are subject to completely different types of errors, the fact that their results are in such good agreement gives us increased confidence in those results," said CU-Boulder physics Professor John Wahr, a study co-author and fellow at the university's Cooperative Institute for Research in Environmental Sciences.

Ground-based estimates of glacier mass changes include measurements along a line from a glacier's summit to its edge, which are extrapolated over a glacier's entire area. Such measurements, while fairly accurate for individual glaciers, tend to cause scientists to overestimate ice loss when extrapolated over larger regions, including individual mountain ranges, according to the team.

Read more at Science Daily

Does Alien Life Thrive in Venus' Mysterious Clouds?

Personally, I’ve always thought that Venus gets a lot of bad press. Sure, it’s wrapped in clouds so strongly acidic that they dissolved the first few probes we tried to land there, and it has a surface temperature high enough to melt lead — but just above the cloud decks of Venus, you’ll find some of the most “Earth-like” conditions in our entire solar system.

This has prompted some astrobiologists to wonder if, contrary to popular belief, Venus may actually be a home to life of some kind. Perhaps we’ve been looking in the wrong place, and life on Venus is not on its surface but in its clouds.

In fact, roughly 50 to 65 kilometers (30-40 miles) above the surface of Venus, conditions are quite hospitable. Both temperature and pressure are similar to those on Earth. Water vapor and even scarce amounts of free oxygen can be found there. There isn’t much, but it’s there.

Astrobiological studies of Venus are, by nature, highly speculative. The notion sounds audacious but, from what we know of Earth life, it’s certainly not implausible. What’s more, there’s still very much about Earth’s twisted sister that we don’t understand.

We know that there are bacteria living in Earth’s clouds. They’re tolerant little beasts too, living in dry conditions, surviving high levels of ultraviolet light and low levels of oxygen. They’re even thought to help clouds to form, particularly in warmer climates.

On Venus, you might think that the potent acid which makes up the clouds may be a hindrance to any kind of Venusian microbes that may live there, but there are extremophile bacteria on Earth that live in similar conditions. One form of bacteria live in caves (the unappealingly named snottites), where they metabolise sulfur and create sulfuric acid. These bacteria create, and thrive in, acid as strong as what you might find in a car battery.

One scientist who’s given a lot of thought to life in unusual environments is Dirk Schulze-Makuch, currently at Washington State University. Something which he and his colleagues were interested by is the fact that the clouds of Venus seem to absorb more ultraviolet light than they should.

Being about 42 million kilometers (26 million miles) closer to the sun than Earth, the upper atmosphere of Venus is bombarded by enough ultraviolet to give lethal sunburn to anything without adequate protection. However, one idea is that molecular rings of sulfur could be giving something just that kind of protection.

Sulfur is plentiful in the atmosphere of Venus, and in its elemental form it likes to make molecules, each containing 8 sulfur atoms. Known as cyclo-octasulfur, these molecules absorb harmful UV and radiate it away at less harmful wavelengths. Could we be seeing sulfur sunblock? Perhaps, but then again perhaps not. Either way, whatever it is which is absorbing all that UV still hasn’t been conclusively identified.

Chemically, there’s definitely some mystery lurking in those beautiful clouds. Certain molecules are found there which shouldn’t be found together. Two in particular, sulfur dioxide (SO2) and hydrogen sulfide (H2S) shouldn’t be found together — when in the same place, they react with each other. The only conclusion is that, somehow, something on Venus must be creating them, otherwise there’d be none for us to see.

Another unexpected chemical in Venus’ atmosphere is known as carbonyl sulfide (OCS). On Earth, carbonyl sulfide is so difficult to create through inorganic processes that it’s been used as an “unambiguous indicator of biological activity“.

There’s one final piece in this bizarre acidic puzzle. The so-called “mode 3 cloud particles.” The clouds of Venus, much like the clouds on any other planet, are a menagerie of tiny droplets and ice crystals made up of the various chemicals found in the atmosphere. These cloud particles are normally fairly easy to identify, but the mode 3 particles are still a mystery.

They’re large, non-spherical, and they contain plenty of sulfuric acid. While it would be ridiculous to make any wild claims, it’s worth considering that those cloud particles are even the same size as bacteria — a notion that David Grinspoon, curator of astrobiology at the Denver Museum of Nature and Science, discussed in his book, Venus Revealed.

Of course, I’m not saying that there actually is life in the vitriolic Venusian clouds. There’s no way anyone could say that for certain, and there are still a lot of criticisms of the idea. The biggest sticking point being the lack of water — while there is some water in those clouds, it’s certainly scarce. All the same, there is something going on on that planet that Venus isn’t telling us. And it doesn’t seem like it’s going to give up its mysteries just yet.

Read more at Discovery News

'Dead' Man Walks Again ... But Why?

In Zimbabwe, mourners attending a funeral recently were stunned when the “dead” man came back to life. According to a story in the Daily Telegraph, “Family and friends were filing past a coffin with the remains of Brighton Dama Zanthe, 34, when one of them noticed the dead man’s legs twitching.

“I was the first to notice Zanthe’s moving legs as I was in the queue to view his body,” said one of the mourners, Lot Gaka, who employs the man at his transport company. “This shocked me. We called an ambulance immediately. It’s a miracle and people are still in disbelief.”

It’s fortunate that Zanthe recovered in time, though not quite a miracle. Stories of people assumed dead but waking up just before burial are weird, but are more common than most people think — especially in Third World countries where modern medical treatment is rare, and confirming death may sometimes be little more than guesswork.

Consciousness does not suddenly stop when the heart stops beating, and people who appear dead in some cases may not be. Cases of people who were presumed dead but woke up shortly before burial  — or, in some horrific cases, shortly after burial — have been around for millennia, and may have contributed to belief in vampires and zombies.

Fears of premature burial obsessed many in the Victorian era and in fact some caskets were equipped with tubes and equipment leading to the surface so that bells and flags could be raised to alert groundskeepers in case the “dead” awoke.

Testing for Death

In centuries past, doctors used a variety of curious methods to determine death, ranging from holding a mirror under a person’s nose to detect moisture in their respiration to pricking the eyes with needles. Usually those sorts of crude measures are enough, but every now and then the vital signs will be too shallow to detect.

The same remains true today, and sometimes medical monitoring machines make errors. Doctors are only human and sometimes they make mistakes. Medical personnel typically don’t spend any more time than necessary with patients they believe to be dead. Instead they, quite reasonably, turn their attention and resources to the injured or diseased patients who they know are living. No one has the responsibility of staying with the dead for hours or days to make sure that they stay dead.

It wasn’t always the case. In his book “Buried Alive: The Terrifying History of Our Most Primal Fear,” researcher Jan Bondeson notes that in the late 1700s French doctors were so concerned about premature burial that they proposed that all major cities in France should have special “waiting mortuaries,” in which the recently deceased would be laid out in rows on floors or tables and carefully watched by monitors who would wander among the corpses looking for signs of anyone coming back to life. It was only at the point in which the bodies would begin bloating and putrefying that the corpse would finally be considered dead enough and sent for burial.

Read more at Discovery News

May 15, 2013

Oldest Evidence of Split Between Old World Monkeys and Apes: Primate Fossils Are 25 Million Years Old

Two fossil discoveries from the East African Rift reveal new information about the evolution of primates, according to a study published online in Nature this week led by Ohio University scientists.

The team's findings document the oldest fossils of two major groups of primates: the group that today includes apes and humans (hominoids), and the group that includes Old World monkeys such as baboons and macaques (cercopithecoids).

Geological analyses of the study site indicate that the finds are 25 million years old, significantly older than fossils previously documented for either of the two groups.

Both primates are new to science, and were collected from a single fossil site in the Rukwa Rift Basin of Tanzania. Rukwapithecus fleaglei is an early hominoid represented by a mandible preserving several teeth. Nsungwepithecus gunnelli is an early cercopithecoid represented by a tooth and jaw fragment.

The primates lived during the Oligocene epoch, which lasted from 34 to 23 million years ago. For the first time, the study documents that the two lineages were already evolving separately during this geological period.

"The late Oligocene is among the least sampled intervals in primate evolutionary history, and the Rukwa field area provides a first glimpse of the animals that were alive at that time from Africa south of the equator," said Nancy Stevens, an associate professor of paleontology in Ohio University's Heritage College of Osteopathic Medicine who leads the paleontological team.

Documenting the early evolutionary history of these groups has been elusive, as there are few fossil-bearing deposits of the appropriate age, Stevens explained. Using an approach that dated multiple minerals contained within the rocks, team geologists could determine a precise age for the specimens.

"The rift setting provides an advantage in that it preserves datable materials together with these important primate fossils," said lead geologist Eric Roberts of James Cook University in Australia.

Prior to these finds, the oldest fossil representatives of the hominoid and cercopithecoid lineages were recorded from the early Miocene, at sites dating millions of years younger.

The new discoveries are particularly important for helping to reconcile a long-standing disagreement between divergence time estimates derived from analyses of DNA sequences from living primates and those suggested by the primate fossil record, Stevens said. Studies of clock-like mutations in primate DNA have indicated that the split between apes and Old

World monkeys occurred between 30 million and 25 million years ago.

"Fossils from the Rukwa Rift Basin in southwestern Tanzania provide the first real test of the hypothesis that these groups diverged so early, by revealing a novel glimpse into this late Oligocene terrestrial ecosystem," Stevens said.

The new fossils are the first primate discoveries from this precise location within the Rukwa deposits, and two of only a handful of known primate species from the entire late Oligocene, globally.

The scientists scanned the specimens in the Ohio University's MicroCT scanner, allowing them to create detailed 3-dimensional reconstructions of the ancient specimens that were used for comparisons with other fossils.

"This is another great example that underscores how modern imaging and computational approaches allow us to address more refined questions about vertebrate evolutionary history," said Patrick O'Connor, co-author and professor of anatomy in Ohio University's Heritage College of Osteopathic Medicine.

In addition to the new primates, Rukwa field sites have produced several other fossil vertebrate and invertebrate species new to science. The late Oligocene interval is interesting because it provides a final snapshot of the unique species inhabiting Africa prior to large-scale faunal exchange with Eurasia that occurred later in the Cenozoic Era, Stevens said.

A key aspect of the Rukwa Rift Basin project is the interdisciplinary nature of the research team, with paleontologists and geologists working together to reconstruct vertebrate evolutionary history in the context of the developing East African Rift System.

"Since its inception this project has employed a multifaceted approach for addressing a series of large-scale biological and geological questions centered on the East African Rift System in Tanzania," O'Connor said.

Read more at Science Daily

Evolution Shapes New Rules for Ant Behavior, Research Finds

In ancient Greece, the city-states that waited until their own harvest was in before attacking and destroying a rival community's crops often experienced better long-term success.

It turns out that ant colonies that show similar selectivity when gathering food yield a similar result. The latest findings from Stanford biology Professor Deborah M. Gordon's long-term study of harvester ants reveal that the colonies that restrain their foraging except in prime conditions also experience improved rates of reproductive success.

Importantly, the study provides the first evidence of natural selection shaping collective behavior, said Gordon, who is also a senior fellow at the Stanford Woods Institute for the Environment.

A long-held belief in biology has posited that the amount of food an animal acquires can serve as a proxy for its reproductive success. The hummingbirds that drink the most nectar, for example, stand the best chance of surviving to reproduce.

But the math isn't always so straightforward. The harvester ants that Gordon studies in the desert in southeast Arizona, for instance, have to spend water to obtain water: an ant loses water while foraging, and obtains water from the fats in the seeds it eats.

The ants use simple positive feedback interactions to regulate foraging activity. Foragers wait near the opening of the nest, and bump antennae with ants returning with food. The faster outgoing foragers meet ants returning with seeds, the more ants go out to forage. (Last year, Gordon, Katie Dektar, an undergraduate, and Balaji Prabhakar, a professor of computer science and of electrical engineering at Stanford, showed that the ants' "Anternet" algorithm follows the same rules as the protocols that regulate data traffic congestion in the Internet).

Colonies differ, however, in how they use these interactions to regulate foraging. Some colonies are likely to forage less when conditions are dry. These same, more successful colonies are also more likely to forage more steadily when conditions are good.

Gordon found that it's more important for the ants to not waste water than to forage for every last piece of food. There's no survival cost to this strategy, even though the colonies sometimes forgo foraging for an entire day. Instead, not only do the colonies that hunker down on the bad days live just as long as those that go all out, they also have more offspring colonies.

"Natural selection is not favoring the behavior that sends out the most ants to get the most food, but instead regulating foraging to hold back when conditions are bad," Gordon said. "This is natural selection shaping a collective behavior exhibited by the entire colony."

Gordon's group is still investigating how the ants gauge humidity, but they have determined that the collective response of the colony to conditions is heritable from parent colony to offspring colony. Even though a daughter queen will establish her new colony so far from the parent colony that the two colonies will never interact, the offspring colonies resemble parent colonies in their sensitivity to conditions.

Although the foraging activity of the offspring colonies and the parent colony didn't entirely match up on all days, they were similar on extreme days: parent and offspring colonies made similar judgments about when to lie low or take advantage of ideal conditions.

Read more at Science Daily

Lost City May Lurk in Honduras Rain Forest

New images of a possible lost city hidden by Honduran rain forests show what might be the building foundations and mounds of Ciudad Blanca, a never-confirmed legendary metropolis.

Archaeologists and filmmakers Steven Elkins and Bill Benenson announced last year that they had discovered possible ruins in Honduras' Mosquitia region using lidar, or light detection and ranging. Essentially, slow-flying planes send constant laser pulses groundward as they pass over the rain forest, imaging the topography below the thick forest canopy.

What the archaeologists found -- and what the new images reveal -- are features that could be ancient ruins, including canals, roads, building foundations and terraced agricultural land. The University of Houston archaeologists who led the expedition will reveal their new images and discuss them today (May 15) at the American Geophysical Union Meeting of the Americas in Cancun.

Ciudad Blanca, or "The White City," has been a legend since the days of the conquistadors, who believed the Mosquitia rain forests hid a metropolis full of gold and searched for it in the 1500s. Throughout the 1900s, archaeologists documented mounds and other signs of ancient civilization in the Mosquitias region, but the shining golden city of legend has yet to make an appearance.

Whether or not the lidar-weilding archaeologists have discovered the same city the conquistadors were looking for is up for debate, but the images suggest some signs of an ancient lost civilization.

"We use lidar to pinpoint where human structures are by looking for linear shapes and rectangles," Colorado State University research Stephen Leisz, who uses lidar in Mexico, said in a statement. "Nature doesn't work in straight lines."

The archaeologists plan to get their feet on the ground this year to investigate the mysterious features seen in the new images.

From Discovery News

2.6 Billion-Year-Old Water Found in Deep Mine

One and a half miles beneath the surface of Earth in a Canadian mine, researchers have found pockets of water in rocks that have been isolated from the surface for some two billion years.

The chemistry of the water could support life, the team reports today in the journal Nature -- a tantalizing discovery that raises the possibility that life-supporting water might also lie in similar kinds of rocks deep beneath the surface of Mars.

Because the water was trapped at a time when Earth was very different than it is today, the new findings also lend insight into the evolution of the early atmosphere and the habitability of the deep Earth. Until now, the oldest known reservoirs of underground water dated back just tens of millions of years.

"For the first time, we found that waters of this age can be preserved on our planet," said Barbara Sherwood Lollar, an isotope geochemist at the University of Toronto. "Really, it's a whole new world, a whole new hydrosphere on our planet. We didn't know it was possible to trap this amount of fluid and gas for this kind of time scale."

Miners have long known that water sometimes flows out of fractures in rocks deep underground, Sherwood Lollar said. As scientists have more recently become interested in the phenomenon, they have discovered that these fluids are often very salty, with salinity levels 10 times higher than seawater.

Deep isolated waters also contain large amounts of dissolved hydrogen, making it possible that they might sustain microorganisms like the ones that live around hydrothermal vents. In 2006, in fact, Sherwood Lollar and colleagues found a community of microbes living deep below South Africa in isolated waters that were tens of millions of years old.

"I refer to hydrogen as the jelly donuts of the microbe world," Sherwood Lollar said. "If it's there, they want to eat it."

For the new study, the researchers lowered a tube-shaped device into pre-drilled boreholes in a mine in Ontario. Water flowed through the device, which separated the gas from the fluid and collected both.

In laboratories in Canada and the United Kingdom, scientists then measured levels of hydrogen, carbon, nitrogen and other stable elements as well as noble gasses such as helium, xenon and krypton. Knowing how quickly chemical reactions proceed over time between rocks and water, the team could then use the levels of those components to determine how long the fluid had been trapped in the deep crust.

Results showed that the water was between one billion and 2.6 billion years old -- orders of magnitude older than the South African samples.

The water dates back to a time before the Great Oxygenation Event that filled Earth's atmosphere with oxygen, making it possible for higher life forms to evolve, said planetary scientist Michael Mumma, director of the Goddard Center for Astrobiology at the NASA Goddard Space Flight Center.

Read more at Discovery News

May 14, 2013

Mysterious Minoans Were European, DNA Finds

The Minoans, the builders of Europe's first advanced civilization, really were European, new research suggests.

The conclusion, published today (May 14) in the journal Nature Communications, was drawn by comparing DNA from 4,000-year-old Minoan skeletons with genetic material from people living throughout Europe and Africa in the past and today.

"We now know that the founders of the first advanced European civilization were European," said study co-author George Stamatoyannopoulos, a human geneticist at the University of Washington. "They were very similar to Neolithic Europeans and very similar to present day-Cretans," residents of the Mediterranean island of Crete.

While that may sound intuitive, the findings challenge a long-held theory that the ancient Minoans came from Egypt.

First European Civilization

The Minoan culture emerged on Crete, which is now part of Greece, and flourished from about 2,700 B.C. to 1,420 B.C. Some believe that a massive eruption from the Volcano Thera on the island of Santorini doomed the Bronze Age civilization, while others argue that invading Mycenaeans toppled the once-great power.

Nowadays, the Minoans may be most famous for the myth of the minotaur, a half-man, half-bull that was fabled to lived within a labyrinth in Crete.

When British archaeologist Sir Arthur Evans discovered the Minoan palace of Knossos more than 100 years ago, he was dumbstruck by its beauty. He also noticed an eerie similarity between Minoan and Egyptian art, and didn't believe that the culture was homegrown.

"That's why Evans postulated the civilization was imported from Egypt or Libya," Stamatoyannopoulos told LiveScience.

Genetic clues

To test that idea, the research team analyzed DNA from ancient Minoan skeletons that were sealed in a cave in Crete's Lassithi Plateau between 3,700 and 4,400 years ago. They then compared the skeletal mitochondrial DNA, which is stored in the energy powerhouses of cells and passed on through the maternal line, with that found in a sample of 135 modern and ancient populations from around Europe and Africa.

The researchers found that the Minoan skeletons were genetically very similar to modern-day Europeans -- and especially close to modern-day Cretans, particularly those from the Lassithi Plateau. They were also genetically similar to Neolithic Europeans, but distinct from Egyptian or Libyan populations.

The findings argue against Evan's hypothesis and suggest that locals, not African expats, developed the Minoan culture.

"It was a period of excitement around the Mediterranean," so although the Minoans definitely had contact with their African neighbors across the Mediterranean, any similarities in art were probably the result of cultural exchange, Stamatoyannopoulos said.

Ancient language?

The findings suggest that the ancient Minoans were likely descended from a branch of agriculturalists in Anatolia (what is now modern-day Turkey and Iraq) that fanned out into Europe about 9,000 years ago. If so, the Minoans may have spoken a proto-Indo-European language derived from the one possibly spoken by those Anatolian farmers, the researchers speculate.

Read more at Discovery News

Earth's Rotating Inner Core Shifts Its Speed

Earth's solid-metal inner core is a key component of the planet, helping to give rise to the magnetic field that protects us from harmful space radiation, but its remoteness from the planet's surface means that there is much we don't know about what goes on down there. But some secrets of the inner core are being revealed by acoustic waves passing through the planet's heart and iron squeezed to enormous pressures in the lab.

Two new studies, both detailed online May 12 in the journal Nature Geoscience, reveal that Earth’s inner core may actually be softer than previously thought, and that the speed at which it spins can fluctuate over time.

Under the liquid-metal outer layer of the Earth's core is a solid ball of superhot iron and nickel alloy about 760 miles (1,220 kilometers) in diameter. Scientists recently discovered the inner core is, at 10,800 degrees Fahrenheit (6,000 degrees Celsius), as hot as the surface of the sun.

Churning in the liquid outer core results in the dynamo that generates Earth's magnetic field. Geoscientists think interactions between the inner and outer cores may help explain the nature of the planet's dynamo, the details of which remain largely unknown.

"The Earth's inner core is the most remote part of our planet, and so there is a lot we don't know about it because we can't go down and collect samples," said Arianna Gleason, a geoscientist at Stanford University in California.

Shifting speeds

One way scientists can learn more about the inner core is by analyzing acoustic waves from earthquakes that ripple through the inner core as they pass through the planet. Hrvoje Tkalcic, a geophysicist at the Australian National University in Canberra, and his colleagues relied on earthquake doublets — earthquakes that occur in pairs and generate extraordinarily similar acoustic waves — to investigate the inner core. Because these waves are so alike, the data they return are readily comparable, and because they are separated relatively briefly in time, they can help the researchers image subtle changes that might occur in that time frame.

Seismic observations and computer models of the Earth's innards suggested the inner core spins at a different rate than the mantle does, but there were conflicting estimates for how fast the inner core actually rotated. By analyzing 24 earthquake doublets, Tkalcic and his collaborators found the speed at which the inner core spun apparently fluctuated over the course of approximately decades between 1961 and 2007.

"It is the first observational evidence that the inner core rotates at a variety of speeds with respect to the mantle...It also reconciles old discrepancies," Tkalcic told OurAmazingPlanet. (Past analyses of how fast the inner core rotated came up with different speeds.)

The inner core, on average, rotates eastward. At the speeds it travels, it might, on average, complete a revolution every 750 to 1,440 years. However, these speeds appear unstable, which makes it uncertain just how long it actually takes to finish a turn on its axis, Tkalcic said.

It remains unknown exactly why these fluctuations in speed happen. Gravitational and magnetic forces likely both play a part, Tkalcic said.

Weak iron

In another study, Gleason and her colleagues sought to learn more about the inner core by mimicking its conditions in the lab. They measured the strength of iron by squeezing it within a diamond anvil at room temperature while scanning it with X-rays.

"We know the Earth's inner core is composed mostly of iron, but we don't really know too much about the behavior of iron under the pressure and temperature at conditions in the core," Gleason said.

The metal was subjected to more than 200 billion pascals of pressure, or about 180,000 times the pressure of the average human bite.

"We found the inherent mechanical strength of iron under those conditions is quite low, surprisingly weak," Gleason said.

These findings may help explain why material within Earth's inner core is apparently distributed in a lopsided way, Gleason said. The weakness of iron might lead crystallites in the inner core to flow and line up a certain way, she explained.

Read more at Discovery News

Why You Should Skip Sanitizer, Just Wash Hands

Antibacterial soaps offer an enticing way to destroy bacteria that can make us sick. But triclosan, a common ingredient in many antibacterial products, has come under fire for possible health and environmental hazards.

Now, the Food and Drug Administration is reviewing the research on triclosan and considering a ban on the chemical. That raises questions about how well antibacterial soaps work in the first place and what we'd lose if they're taken off the market.

Does scrubbing with bacteria-destroying products actually prevent illnesses? Or is it making things worse?

Hand washing remains an important way to stay healthy, experts said, especially during the winter months. But regular soap and water or alcohol-based hand-sanitizers work just as well as triclosan-containing products do, without any of the potential concerns.

"It's clear that triclosan targets some bacteria but not all, but it's not effective against viruses, and viruses cause the majority of illnesses in a community setting,&r" said Allison Aiello, an epidemiologist at the University of Michigan School of Public Health in Ann Arbor.

"It seems strange to support or promote a product that targets specific bacteria but doesn't actually target the viruses that cause most of the illnesses in a household. To me, that doesn't make much sense."

Triclosan was first registered as a pesticide in 1969, according to a fact page maintained by the United States Environmental Protection Agency. Since then, the chemical has been added to toothpastes, hand soaps, body washes, cutting boards, toys, carpets, mattresses, clothes, furniture and a wide variety of other products with the goal of fighting bacteria, fungi and mildew.

At first, triclosan was thought to act as a universal bacteria-killer but beginning in 1998, Stuart Levy and colleagues at Tufts University found that the chemical targets specific bacteria and that bacteria can become resistant to triclosan with a mutation in genes required to build cell walls.

A new class of antibiotics was structured like triclosan, Levy added, raising concerns that the chemical could be contributing to the development of antibiotic-resistant bacteria by favoring the survival and growth of microbes that were immune to the chemical.

Other research has shown that triclosan acts like a hormone disruptor in animals. Once triclosan moves from bathroom drains to lakes and rivers, it also breaks down into dioxins, which can cause all sorts of health problems, including birth defects and cancer.

And a 2006 study in Sweden found triclosan in breast milk at higher concentrations in women who used soap, deodorant or toothpaste that contained the chemical.

In a review article published in 2007 in the journal Clinical Infectious Disease, Aiello and colleagues looked at 27 studies that compared triclosan-containing products to regular soap and found that people were no less likely to come down with diarrhea, coughs, fevers or skin infections if they used the chemical-laden soap in their homes.

Some studies looked specifically at the bacterial load on hands before and after washing, and likewise, most of those found no difference between the two kinds of soap and their ability to rid bacteria from our hands. There may be some kinds of bacteria that are more effectively killed by triclosan, Aiello added, but not many, and those bacteria are not the ones that cause common illnesses.

Instead of killing bacteria, regular soap simply removes bacteria from the crevices in our hands, allowing them to be washed down the drain, said Levy, director of the Center for Adaptation Genetics and Drug Resistance at Tufts. After washing with soap and water (which works significantly better than just water), he advocates drying with paper towels because bacteria can linger on moist hand towels in the bathroom.

Read more at Discovery News

Ancient Ocean Bacteria Feasted on Supernova Dust

Massive stars are like gargantuan element foundries. For millions of years, they react atomic nuclei together into increasingly heavier chemical elements, before exploding as supernovae and scattering those elements out into the cosmos. Many of the elements created in supernovae are essential to life on Earth, and now for the first time ever, life on Earth has provided some rather unusual evidence for a supernova 2.2 million years ago.

A study carried out by researchers at the Technische Universitaet Muenchen (TUM), published in Nature, concerns a particular kind of iron loving bacteria known as magnetotactic bacteria. These particular microbes live in ocean sediments, where they metabolise iron to create tiny crystals of iron oxide — a particular type of iron oxide, known as magnetite (Fe3O4).

The magnetite crystals made by these bacteria are quite uniform, each just 80 nanometres (80 billionths of a meter) in size. The iron they use comes from dust in Earth’s atmosphere, which finds its way into the ocean. And every so often, they metabolise iron, which originally came from a supernova.

When a supernova explodes, nuclear fusion goes wild. Elements fuse together haphazardly, creating unusual and unstable radioactive isotopes. This is the only natural way in which certain elements, such as uranium, can be created. One particular isotope formed this way is iron-60.

In fact, iron-60 is created almost exclusively in supernovae. With a half life of 2.6 million years, any iron-60 which was on Earth back when it formed is long gone, so finding any of this form of iron on Earth is excellent evidence for a nearby supernova sometime in the (relatively) recent past.

Shawn Bishop, a nuclear astrophysicist, and his colleagues analyzed sediment cores drilled from the floor of the Pacific Ocean. In those sediment samples, they found fossilized bacteria — and in those fossils, they found iron-60.

Studying sediment samples aged between 1.7 and 3.3 million years, they looked at intervals every 100,000 years, chemically extracting the bacterial fossils to analyze the magnetite crystals created at the time. They then tested those fossils at the Maier Leibnitz Laboratory in Garching, Munich, using an ultra sensitive mass spectrometer. The result was a glimpse of iron-60 in the fossils, providing the first ever evidence for a near-Earth supernova given directly by Earth life.

What’s more, the bacterial iron-60 was dated to approximately 2.2 million years ago. This coincides perfectly with a previous study in 2004, where researchers found the same iron isotope in Earth’s crust. This was the first time the isotope had been found on our planet, and was also found buried under the Pacific Ocean floor.

While this is still a preliminary (and somewhat tantalizing) result, it’s certainly an impressive one. It also confirms that there was very likely a supernova near to our solar system roughly 2.2 million years ago, and that ash from that supernova made its way onto the surface of our planet.

Read more at Discovery News

Einstein's BEER Planet Discovered

Astronomers have announced the discovery of Kepler-76b — a “hot Jupiter” that takes only 1.5 days to complete an orbit around its star. Unofficially, however, Kepler-76b has been nicknamed “Einstein’s planet” as it was discovered using a novel method that applies a weird relativistic effect as theorized by Albert Einstein.

Usually, NASA’s Kepler space telescope looks for the very slight dips in starlight brightness as exoplanets orbit in front of their host stars from our perspective. Kepler is revolutionizing exoplanetary studies as it is sensitive to the detection of tiny worlds, which is only possible owing to the mission’s advanced optics.

Now, using Kepler data, astronomers have taken a different tact in the hunt for exoplanets.

Kepler-76b was discovered by looking for the slight brightening of a star as an exoplanet passes in front. How does that work?

Normally, as an exoplanet passes in front of a star’s disk, Kepler will detect a dip in brightness in that star’s “light curve.” The greater the dip, the bigger the planet. But this method only works if the orbital plane of the planet is exactly “edge-on” when viewed from Earth. What if there’s an exoplanetary system with an orbital plane inclined away from our point of view? To put it bluntly, Kepler won’t see those exoplanets — or will it?

In 2003, Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA) and Scott Gaudi (now at Ohio State University) had an idea. By their reckoning, if the optics of a space telescope are sensitive enough, the Einstein “beaming effect” should be observable. And on Monday, it was announced that this strange quirk in physics revealed the presence of Kepler-76b.

So, what is this beaming effect and how can it help in the search for exoplanets?

As Kepler-76b orbits its star, it “tugs” on the stellar body. Indeed, it’s this tugging effect that allows another exoplanet-hunting technique to come in to play. The “radial velocity” method is extensively used by ground-based observatories to detect the wobble of stars — as the exoplanet pulls the star toward us, its electromagnetic spectrum is slightly blue-shifted, as it’s pulled away, the spectrum is slightly red-shifted.

Relativistic beaming works in a similar manner, but there is no requirement to analyze the star’s spectrum.

As Kepler-76b is 25 percent larger than Jupiter and twice as massive, it has a sizable tugging effect on the star. The beaming effect occurs when the orbiting exoplanet tugs its star in our direction — the motion toward us creates a focusing effect on the photons we receive from the star — the photons to “bunch up” in the direction of travel, concentrating their energy, brightening the star.

This is the first time the effect has been applied to exoplanetary detection.

“We are looking for very subtle effects,” said team member David Latham of the CfA. “We needed high quality measurements of stellar brightnesses, accurate to a few parts per million,”

“This was only possible because of the exquisite data NASA is collecting with the Kepler spacecraft,” added lead author Simchon Faigler of Tel Aviv University, Israel.

Impressive as this detection may be, the team also wanted to test out two more very subtle of ways the massive exoplanet may be detected. While tugging on the star, the exoplanet elongates the star into a football shape due to the massive tidal forces exerted it. Therefore, the Kepler light-curve should also detect a slight brightening when it views the star from the side (as the “side” will have a larger surface area to radiate light than the “end”). Also, they wanted to see if they could detect the reflected light from the planet’s atmosphere too — another very faint, but measurable effect. They succeeded on all counts.

As a bonus, they also found observational evidence for violent jet streams in the exoplanet’s atmosphere, generating “hotspots” in the atmosphere, offset from the closest point to the star’s energy. The planet is “tidally locked” with its star (i.e. the same hemisphere always faces the star), so standing jetstreams blast from “high noon” (the location of the star, directly overhead) through the atmosphere, creating hotspots 10,000 miles away from noon.

Read more at Discovery News

May 13, 2013

Alligators Inspire New Way for Growing Teeth

American alligators have a smile that only a mother could love, but new research finds that these huge meat-loving reptiles could help to revolutionize tooth replacement in humans.

The statistics about alligator teeth are remarkable. Most individuals go through around 3,000 teeth in a lifetime. It’s estimated that a 13-foot-long alligator replaces each of its 80 teeth about 50 times throughout the animal’s existence.

Now the light bulb moment for scientists is that alligator teeth are not all that dissimilar from human ones. The main difference is that when an adult human loses a tooth, it’s gone forever.

(That offers an interesting clue as to what kind of diet our early human ancestors had. It couldn’t have been too hard or tough, or else we would have evolved a better tooth replacement system.)

For this latest study, published in the Proceedings of the National Academy of Sciences, Cheng-Ming Chuong of National Taiwan University and colleagues studied repetitive tooth formation in American alligators. Detailed imaging of gator teeth determined that at the early tooth development stage, the alligator’s dentine bone-like material forms a bulge at its tip. The tip houses what are believed to be dormant stem cells.

When the gator loses a tooth, certain types of proteins are released that activate these stem cells. The proteins quickly go into action, initiating growth of a new tooth. This happened even when researchers pulled out alligator teeth.

By identifying the individual types of “activator” proteins and the stem cells, the scientists can likely apply the tooth renewal process to humans with missing teeth.

As Chuong and colleagues wrote, “Based on our study, it may be possible to identify the regulatory network for tooth cycling. This knowledge will enable us to either arouse latent stem cells in the human dental lamina remnant to restart a normal renewal process in adults who have lost teeth or stop uncontrolled tooth generation in patients with supernumerary teeth.”

Clinical trials on humans are underway, after researchers successfully caused teeth to regrow in mice and monkeys.

Read more at Discovery News

Stunning Byzantine Mosaic Uncovered in Israel

Archaeologists have uncovered an "extraordinary" mosaic that would've been used as the floor of a public building during the Byzantine Period in what is today Israel, the Israel Antiquities Authority (IAA) announced.

The colorful mosaic and public building, whose ceiling was covered in roof tiles, were uncovered in Kibbutz Bet Qama, in the B'nei Shimon regional council, prior to the construction of a road between Ma'ahaz and Devira Junction.

"The minute we started excavating we found the mosaic, before we found the edges of the building," Davida Eisenberg Degen, an archaeologist with the IAA, told LiveScience during an interview.

The mosaic would've extended the area of the main building, with a total area about 40 feet long by 28 feet wide (12 meters by 8.5 meters). Divided into three squares with circles within each, the mosaic was decorated with "interwoven designs," Degen said. At each corner were amphoras, or jars used to hold wine, and other designs, such as two peacocks flanking an amphora, a dove and a partridge, and one amphora with a pomegranate and a lemonlike fruit inside.

Though other areas of the site showed evidence of the practice of Christianity, the public building seemed to have no religious affiliation. The researchers aren't sure what it would've been used for between the fourth and sixth centuries A.D.

"The find of this mosaic is extraordinary; the size of it and the goes beyond what is usually found," Degen said. "This is an unusual find."

In front of the building, archaeologists had also discovered pools and a network of channels and pipes used to convey water between them. Steps were uncovered in one of the pools, the walls of which were covered in colored plaster, called fresco.

Archaeologists are trying to figure out the purpose of the building and pools, though they say the construction of the structures would have required considerable economic resources.

The site of the excavation is located on an ancient road that ran north from Be'er Sheva and also includes a large estate with a church and a large cistern surrounded by farmland. One of the structures likely served as an inn for visitors, the researchers speculate.

Read more at Discovery News

Mystery Eternal Flame Reveals New Gas Source

Nestled behind a waterfall in western New York state is an eternal flame whose beauty is only surpassed by its mystery. It is one of a few hundred "natural" eternal flames around the world, fed by gas seeping to the Earth's surface from underground, said Arndt Schimmelmann, a researcher at Indiana University in Bloomington, Ind.

But even within this rarefied group, this flame is special. Perhaps lit by Native Americans hundreds or thousands of years ago, it is fed by a new type of geologic process that hasn't been recorded before in nature, Schimmelmann told OurAmazingPlanet.

Typically, this type of gas is thought to come from deeply submerged, ancient and extremely hot deposits of shale, a kind of rock. Temperatures have to be near the boiling point of water or hotter to break down the large carbon molecules in shale and create smaller molecules of natural gas, Schimmelmann explained.

A curiosity "nobody believed in"

In this case, though, the rocks that feed the flame are only warm — "like a cup of tea" — as well as geologically younger than expected, and shallow, Schimmelmann said. Those findings suggest the gas is being produced by a different process, whereby some sort of catalyst is creating gas from organic molecules in the shale, he said.

"This mechanism has been proposed for many years, but it was a curiosity that nobody believed in," Schimmelmann said. "We think there's a different pathway of gas generation in this location and that there probably is elsewhere as well." If that's true, and gas is naturally produced this way in other locations, "we have much more shale-gas resources than we thought," he added.

Originally, Schimmelmann and his colleague Maria Mastalerz, of the Indiana Geological Survey, were tasked by the U.S. Department of Energy to estimate the total amount of methane that seeps out of the ground in parts of the eastern United States. To help, they recruited Giuseppe Etiope, a researcher at the National Institute of Geophysics and Volcanology in Italy, and world expert on natural gas seeps and eternal flames, Schimmelmann said.

A flame eternal

Etiope guided the researchers to the aforementioned eternal flame in Chestnut Ridge Park in western New York, calling it "the most beautiful in the world," Schimmelmann said. They also looked at a "permanently burning pit" in Cook Forest State Park in northwestern Pennsylvania, although this eternal flame is not as special because it’s supplied by an old gas well, Schimmelmann said. The team reported their findings on the New York eternal flame in a study published in the May issue of the journal Marine and Petroleum Geology.

Their results were consistent with estimates that about 30 percent of all methane emitted worldwide comes from natural sources such as these gas seeps. When possible, it can actually be beneficial to set fire to these gas seeps to create "eternal flames." Fire converts methane to carbon dioxide, which traps about 20 times less heat than methane in the atmosphere, Mastalerz told OurAmazingPlanet.

Read more at Discovery News

Pulsar Planets: Strange Worlds Orbiting Undead Stars

Imagine a planet in orbit around a dead star. The world would be bathed in a lethal cocktail of X-rays and charged particles, emitted by a star so faint in visible light that it will scarcely cast a shadow on this world’s surface. This may all sound like science fiction, but bizarre worlds like this really do exist.

We’re steadily discovering more and more exoplanets around distant stars and, excitingly, we’re finding planets that are more and more Earth-like. That said, it’s easy to forget that the first exoplanets discovered weren’t actually very Earth-like at all. In fact, the first exoplanet to be discovered was in orbit around a pulsar — a star that is long dead.

Pulsars are the tiny, corpse-like remnants of once mighty stars. A type of rapidly spinning neutron star, pulsars are tightly compacted balls of bizarre neutron-rich matter, formed when some of the largest stars in the universe explode as supernovae. These may not seem, at first, to be good places to look for planets. Supernovae are, frankly, quite apocalyptic events that would easily vaporize any ill-fated planets in orbit around the exploding star.

Weird Worlds

Nonetheless, we know of a handful of planets orbiting these strange, undead suns. The first such discovery was made over two decades ago, around a pulsar known as PSR 1257+12. Pulsars emit two beams of radiation from their magnetic North and South poles. Because the star’s magnetic poles don’t line up with the way the it rotates, this means that we see flashes whenever a beam is pointing towards us — exactly the way we see flashes of light from a lighthouse on the horizon.

The pulses we see from here on Earth are so regular that you could set your watch by them, but this also means that any changes in the pulse timing is quite easy to spot. If a pulsar carries planets in tow, the tiny gravitational tugs they make as they orbit can offset that timing ever so slightly. The effect is miniscule, but it’s there.

PSR 1257+12 in particular, is a millisecond pulsar — it spins so rapidly that these tiny changes can be noticed fairly easily. So easily in fact, that this particular pulsar is now known to have a system of three planets around it. Two of these are super-Earths, and one is barely more massive than Earth’s moon — it was the smallest known exoplanet until quite recently.

Meanwhile, around another pulsar is a planet known as PSR B1620-26 b. This one is actually a giant, two and a half times as massive as Jupiter, and it’s no less unusual. PSR B1620-26 b is the oldest planet we know of. Its venerable age of 12.7 billion years makes it nearly as old as the Universe itself, earning it the nickname of “Methuselah” among some people*, and hinting that planets may have been forming in our Universe for a very long time.

Worlds such as these are most certainly “alien” planets, in that they’re so different to anything we know of that it’s difficult to even guess at what they may be like close up. If these worlds have an atmosphere, then they may have dazzling planet-wide aurorae. Bathed in charged particles from the pulsars they orbit, molecules in these planets’ atmospheres would be constantly torn apart, causing them to emit huge bursts light. On the other hand, if a pulsar planet has no atmosphere, its surface will most likely be scoured by lethal x-rays.

As for Methuselah, it’s difficult to say for certain what happens to a gas giant after 12 billion years. The giant planets in our own solar system are actually still cooling. Jupiter, in particular, is known to emit more energy in infrared light than it receives from the sun. This is because of a process called Kelvin-Helmholtz heating, and it means that Jupiter is actually shrinking by around 2 centimeters each year. Over the course of a human lifetime, this is barely noticeable. But Methuselah is over 8 billion years older than Jupiter.

Curiouser and Curiouser

Yet other pulsar planet is, somehow, stranger still. PSR J1719-1438 b, discovered in 2011, is believed to be made up mostly of carbon, crystallised into diamond. It’s technically an ultra low mass white dwarf star, which had most of its mass stolen by the the pulsar it orbits. The remnant has no more mass than Jupiter, making it more planet-like than star-like.

Because of this unusual history, PSR J1719-1438 b is considered a planet. In fact, it’s the densest planet ever discovered, with intense pressures found below its surface which would cause carbon to crystallize. This sounds beautiful, but unfortunately for future sightseers, the gravity at the surface of this strange world would be enough to crush any visitors instantly. Provided they could survive the radiation from the pulsar, that is.

An interesting question that may spring to mind is, with the recent conjectures about possible life sustaining white dwarf stars, could any pulsar planets be home to some kind of life? Frankly, it’s extremely unlikely, as disappointing as that may seem.

I never like to use the word impossible, but conditions around a pulsar are so hostile that the kind of molecules that life as we know it are made from would be fragmented rapidly. To speculate briefly, even if any life could exist on planets such as these, it would have to live deep below the surface of its planet, and would probably be so different that we’d have trouble even recognizing it.

In the past few years, fewer pulsar planets have been discovered, and a few previous detections have been disproven. There’s a good chance though, that this may be because not many people are looking anymore. Most exoplanet researchers are being kept quite busy by almost 900 confirmed exoplanets so far discovered, and over 18,000 further candidates. Thanks to missions like Kepler, there’s a lot of data to sift through.

Read more at Discovery News

May 12, 2013

Nano-Breakthrough: Solving the Case of the Herringbone Crystal

Leading nanoscientists created beautiful, tiled patterns with flat nanocrystals, but they were left with a mystery: Why did some sets of crystals arrange themselves in an alternating, herringbone style? To find out, they turned to experts in computer simulation at the University of Michigan and the Massachusetts Institute of Technology.

The result gives nanotechnology researchers a new tool for controlling how objects one-millionth the size of a grain of sand arrange themselves into useful materials -- and a means to discover the rest of the tool chest. A paper on the research is published online May 12 in Nature Chemistry.

"The excitement in this is not in the herringbone pattern, it's about the coupling of experiment and modeling, and how that approach lets us take on a very hard problem," said Christopher Murray, the Richard Perry University Professor and professor of chemistry at the University of Pennsylvania.

Murray's group is well-known for making nanocrystals and arranging them into larger crystal superstructures.

Ultimately, researchers want to modify patches on nanoparticles in different ways to coax them into more complex patterns. The goal is a method that will allow people to imagine what they would like to do and then design a material with the right properties for the job.

"By engineering interactions at the nanoscale, we can begin to assemble target structures of great complexity and functionality on the macroscale," said U-M's Sharon Glotzer, the Stuart W. Churchill Collegiate Professor of Chemical Engineering.

Glotzer introduced the concept of nanoparticle "patchiness" in 2004. Her group uses computer simulations to understand and design the patches.

Recently, Murray's team made patterns with flat nanocrystals made of heavy metals, known to chemists as lanthanides, and fluorine atoms. Lanthanides have valuable properties for solar energy and medical imaging, such as the ability to convert between high- and low-energy light.

They started by breaking down chemicals containing atoms of a lanthanide metal and fluorine in a solution, and the lanthanide and fluorine naturally began to form crystals. Also in the mix were chains of carbon and hydrogen that stuck to the sides of the crystals, stopping their growth at sizes of around 100 nanometers, or 100 millionths of a millimeter, at the largest dimensions. By using lanthanides with different atomic radii, they could control the top and bottom faces of the hexagonal crystals to be anywhere from much longer than the other four sides to non-existent, resulting in a diamond shape.

To form tiled patterns, the team spread a thin layer of nanocrystals and solvent on top of a thick fluid. As the solvent evaporated, the crystals had less space available, and they began to pack together.

The diamond shapes and the very long hexagons lined up as expected, the diamonds forming an Argyle-style grid and the hexagons matching up their longest edges like a foreshortened honeycomb. The hexagons whose sides were all nearly the same length should have formed a similar squashed honeycomb pattern, but instead, they lined up in more complicated, alternating herringbone style.

"Whenever we see something that isn't taking the simplest pattern possible, we have to ask why," Murray said.

They posed the question to Glotzer's team.

"They've been world leaders in understanding how these shapes could work on nanometer scales, and there aren't many groups that can make the crystals we make," Murray said. "It seemed natural to bring these strengths together."

Glotzer and her group built a computer model that could recreate the self-assembly of the same range of shapes that Murray had produced. The simulations showed that if the equilateral hexagons interacted with one another only through their shapes, most of the crystals formed the foreshortened honeycomb pattern -- not the herringbone.

"That's when we said, 'Okay, there must be something else going on. It's not just a packing problem,'" Glotzer said.

Her team, which included U-M graduate student Andres Millan and research scientist Michael Engel, then began playing with interactions between the edges of the particles. They found that that if the edges that formed the points were stickier than the other two sides, the hexagons would naturally arrange in the herringbone pattern.

The teams suspected that the source of the stickiness was those carbon and hydrogen chains -- perhaps they attached to the point edges more easily. Since experimentation doesn't yet offer a way to measure the number of hydrocarbon chains on the sides of such tiny particles, Murray asked Ju Li, now the Battelle Energy Alliance Professor of Nuclear Science and Engineering at the Massachusetts Institute of Technology, to calculate how the chains would attach to the edges at a quantum mechanical level.

Li's group confirmed that because of the way that the different facets cut across the lattice of the metal and fluorine atoms, more hydrocarbon chains could stick to the four edges that led to points than the remaining two sides. As a result, the particles become patchy.

"Our study shows a way forward making very subtle changes in building block architecture and getting a very profound change in the larger self-assembled pattern," Glotzer said. "The goal is to have knobs that you can change just a little and get a big change in structure, and this is one of the first papers that shows a way forward for how to do that."

Read more at Science Daily

Carnivorous Plant Throws out 'Junk' DNA

Genes make up about 2 percent of the human genome. The rest consists of a genetic material known as noncoding DNA, and scientists have spent years puzzling over why this material exists in such voluminous quantities.

Now, a new study offers an unexpected insight: The large majority of noncoding DNA, which is abundant in many living things, may not actually be needed for complex life, according to research set to appear in the journal Nature.

The clues lie in the genome of the carnivorous bladderwort plant, Utricularia gibba.

The U. gibba genome is the smallest ever to be sequenced from a complex, multicellular plant. The researchers who sequenced it say that 97 percent of the genome consists of genes -- bits of DNA that code for proteins -- and small pieces of DNA that control those genes.

It appears that the plant has been busy deleting noncoding "junk" DNA from its genetic material over many generations, the scientists say. This may explain the difference between bladderworts and junk-heavy species like corn and tobacco -- and humans.

The international research team, led by the Laboratorio Nacional de GenĂ³mica para la Biodiversidad (LANGEBIO) in Mexico and the University at Buffalo, will report its findings on May 12 in Nature.

The study was directed by LANGEBIO Director and Professor Luis Herrera-Estrella and UB Professor of Biological Sciences Victor Albert, with contributions from scientists in the United States, Mexico, China, Singapore, Spain and Germany.

"The big story is that only 3 percent of the bladderwort's genetic material is so-called 'junk' DNA," Albert said. "Somehow, this plant has purged most of what makes up plant genomes. What that says is that you can have a perfectly good multicellular plant with lots of different cells, organs, tissue types and flowers, and you can do it without the junk. Junk is not needed."

Noncoding DNA is DNA that doesn't code for any proteins. This includes mobile elements called jumping genes that have the ability to copy (or cut) and paste themselves into new locations of the genome.

Scientists have spent countless hours puzzling over why noncoding DNA exists -- and in such copious amounts. A recent series of papers from ENCODE, a highly publicized international research project, began to offer an explanation, saying that the majority of noncoding DNA (about 80 percent) appeared to play a role in biochemical functions such as regulation and promotion of DNA conversion into its relative, RNA, which for genes, feeds into the machinery that makes proteins.

But Herrera-Estrella, Albert and their colleagues argue that organisms may not bulk up on genetic junk for reasons of benefit.

Instead, they say, some species may simply have an inherent, mechanistic bias toward deleting a great deal of noncoding DNA while others have a built-in bias in the opposite direction -- toward DNA insertion and duplication. These biases are not due to the fact that one way of behaving is more helpful than the other, but because there are two innate ways to behave and all organisms adhere to them to one degree or the other. The place that organisms occupy on this sliding scale of forces depends in part on the extent to which Darwin's natural selection pressure is able to counter or enhance these intrinsic biases.

The new U. gibba genome shows that having a bunch of noncoding DNA is not crucial for complex life. The bladderwort is an eccentric and complicated plant. It lives in aquatic habitats like freshwater wetlands, and has developed corresponding, highly specialized hunting methods. To capture prey, the plant pumps water from tiny chambers called bladders, turning each into a vacuum that can suck in and trap unsuspecting critters.

The U. gibba genome has about 80 million DNA base pairs -- a miniscule number compared to other complex plants -- and the deletion of noncoding DNA appears to account for most of that size discrepancy, the researchers say. U. gibba has about 28,500 genes, comparable to relatives like grape and tomato, which have much larger genomes of about 490 and 780 million base pairs, respectively.

The small size of the U. gibba genome is even more surprising given the fact that the species has undergone three complete genome doublings since its evolutionary lineage split from that of tomato.

That is, at three distinct times in the course of its evolution, the bladderwort's genome doubled in size, with offspring receiving two full copies of the species' entire genome. "This surprisingly rich history of duplication, paired with the current small size of the bladderwort genome, is further evidence that the plant has been prolific at deleting nonessential DNA, but at the same time maintaining a functional set of genes similar to those of other plant species" says Herrera-Estrella.

Read more at Science Daily