Science News

[Duke of Buckingham]

Stone Age art gets animated
Ancient cave paintings depict moving animals

By Bruce Bower
Web edition : Friday, June 1st, 2012

Welcome to Animation Domination, Stone Age style. By about 30,000 years ago, Europeans were using cartoon-like techniques to give observers the impression that lions and other wild beasts were charging across cave walls, two French investigators find.

Ancient artists created graphic stories in caves and illusions of moving animals on rotating bone disks, say archaeologist Marc Azéma of the University of Toulouse–Le Mirail in France and Florent Rivère, an independent artist based in Foix, France.

“Stone Age artists intended to give life to their images,” Azéma says. “The majority of cave drawings show animals in action.”

Flickering torches passed over painted scenes would have heightened onlookers’ sense of seeing live-action stories, the researchers suggest in the June Antiquity.

Azéma and Rivère summarize their 20 years of research on Stone Age animation techniques, much of it previously published in French, in the new paper. They also describe for the first time examples of animation at two French caves, Chauvet and La Baume Latrone.

“Movement and action are indeed represented in cave art in different manners,” remarks archaeologist Jean Clottes, a rock-art specialist who now serves as honorary conservator general of heritage for the French Ministry of Culture. Clottes led a 1998 investigation of Chauvet’s 30,000-year-old cave paintings.

A 10-meter-long Chauvet painting represents a hunting story, Azéma proposes. The story begins by showing several lions, ears back and heads lowered, stalking prey. Mammoths and other animals appear nearby. In a second section of the painting, a pride of 16 lions, some drawn smaller than the rest to appear farther away, lunge toward fleeing bison.

Stone Age artists meant to depict animal movement in such scenes, Azéma says. An eight-legged bison at Chauvet, for example, resulted from superimposing two images of the creature in different stances to create the appearance of running.

In France, 53 figures in 12 caves superimpose two or more images to represent running, head tossing and tail shaking. At the famous Lascaux Cave, 20 painted animals display multiple heads, legs or tails.

A carving on an animal bone from another Stone Age cave in France depicts three freeze-frame images of a running lion, another way to represent motion.

Ancient Europeans also invented a kind of animation toy, the researchers suggest. Sites in France and Spain have yielded stone and bone disks, typically with center holes, showing opposing images of sitting and standing animals.

In experiments conducted since 2007, Rivère has reproduced these engraved disks and looped strands of animal tendon through the center holes. By twisting these strands, the disks rotate back and forth rapidly enough to make animals appear to be sitting down and standing up.

That’s the principle behind the thaumatrope, a device invented (or perhaps reinvented) in 1825. Two strings attached to the ends of a disk or card with an image on each side — say, a vase opposite a bouquet of flowers — were twirled between the fingers, so that the rotating pictures appeared to combine into a single image, such as flowers in a vase.

Thaumatropes are considered precursors of movie cameras and animation.

Ancient artists at France's Chauvet Cave superimposed drawings of two bison to create an eight-legged beast intended to depict trotting or running, two researchers say. Credit: M. Azema, J. Clottes, Chauvet Cave scientific team

[Duke of Buckingham]

How a mosquito survives a raindrop hit
Lightweight insects can ride water droplets, as long as they separate in time

By Susan Milius
Web edition : Monday, June 4th, 2012

A raindrop hitting a mosquito in flight is like a midair collision between a human and a bus. Except that the mosquito survives.

New experiments show how the insect’s light weight works in its favor, says engineer David Hu of the Georgia Institute of Technology in Atlanta. In essence, the (relatively) huge, fast drop doesn’t transfer much of its momentum to a little wisp of an insect. Instead the falling droplet sweeps the insect along on the downward plunge. As Hu puts it, the mosquito “just rides the drop.”

The trick is breaking away from that drop before it and the insect splash into the ground. Mosquitoes that separate themselves in time easily survive a raindrop strike, Hu and his colleagues report online June 4 in the Proceedings of the National Academy of Sciences.

Such studies help reveal how animals evolved to take advantage of flight, says biologist Tyson Hedrick of the University of North Carolina at Chapel Hill. Mosquito tricks may also inspire engineers designing swarms of tiny flying robots, or interest physicists and mathematicians studying complex fluid dynamics at this scale.

Plenty of lab work has investigated how flying animals recover from disturbances, but there’s little work on raindrops because those collisions are very hard to study, Hu says. To mimic raindrop speed of about 9 meters per second, he and his colleagues tried dripping water off the third floor of a building toward ground-level mosquitoes. “It’s the worst game of darts you can imagine,” he says. “You have no hope of hitting them.”

Finally, Hu sprayed streams of water from a pump at caged lab mosquitoes and then refined the process by spraying mosquito-sized beads. His team found that mosquitoes hit with water survived using an insect version of tai chi: Move with the blow instead of resisting it. A raindrop can reach 50 times the mass of a mosquito, and after colliding, “the mosquito becomes a stowaway,” Hu says.

The wild ride comes with danger. Mosquitoes hitchhiking on water experience acceleration 100 to 300 times the force of Earth’s gravity, the researchers found. The previous champs for surviving acceleration had been jumping fleas, at a mere 130 times Earth’s gravity.

Such studies suggest insects are making tradeoffs, Hedrick says. Mosquitoes’ small mass might allow them fly through raindrops but leave them more vulnerable to other menaces, such as wind. Larger and heavier horseflies “should have no problem with wind but might be more disturbed by raindrop impacts,” he says.

Scientists who work in the field know how readily mosquitoes can survive wet weather. “I’ve worked in the field many rainy nights,” says entomologist Nathan Burkett-Cadena of the University of South Florida in Tampa, “and received zero respite from mosquitoes during even heavy rains.”

A mosquito survives being walloped by a raindrop by riding along on its descent to the ground, scientists have found. Credit: Courtesy Tim Nowack, Andrew Dickerson and David Hu/Georgia Tech


Water drops slamming into insects can knock them partly or completely off course, this laboratory video shows.

Credit: Courtesy Andrew Dickerson and David Hu/Georgia Tech

[Duke of Buckingham]

Some newfound planets are something else
Re-evaluation suggests one-third of hot giant orbs are misclassified

By Nadia Drake
Web edition : Thursday, June 7th, 2012

When the Kepler spacecraft finds a giant planet closely orbiting a star, there’s a one in three chance that it’s not really a planet at all.

At least, that’s the case according to a new study that put some of Kepler’s thousands of candidate planets to the test using a complementary method for discovering celestial objects in stellar orbits. The results, posted June 5 on arXiv.org, suggest that 35 percent of candidate giants snuggled close to bright stars are impostors, known in the planet-hunting business as false-positives.

“Estimating the Kepler false-positive rate is one of the most burning questions in this field,” says astronomer Jean-Michel Désert of the Harvard-Smithsonian Center for Astrophysics, who has performed similar calculations for smaller planets.

Estimates by Désert and others place the false-positive rate at less than 10 percent, which isn’t necessarily contradictory given the different target populations of various research efforts.

“We cannot say anything about smaller planets,” says Alexandre Santerne, a graduate student at the University of Aix-Marseille in France and coauthor of the arXiv.org paper. “It’s just for giant planets close-in.”

Kepler looks for the periodic dimming of starlight produced by planets passing between Earth and their home stars near the constellation Cygnus. But not everything that darkens a star is a planet; smaller stars, for example, might masquerade as a planet. Instead of detecting periodic twinkles, Santerne and his colleagues looked for gyrations in host stars, the wiggles produced by orbiting planets’ gravitational tugs. Since heavy, nearby planets yank more noticeably on their stars, the team focused on giant candidates with orbits of 25 days or less.

Out of more than 2,300 possible planets, only 46 fell into that category. Eleven of these were already known planets. Santerne’s team confirmed nine more.

The remaining 26 candidates included 13 unknowns, two failed brown dwarf stars, and 11 members of binary star systems. “These can mimic clearly a planetary transit event,” says Santerne. “That’s why it’s so important to distinguish these things when you want to study planets and transits from the Kepler mission.”

After distributing the unknowns according to the observed ratios of objects, the team arrived at the 35 percent false-positive rate.

That number might seem high when compared with previous estimates, but scientists don’t consider it a serious flaw for Kepler. “This false-positive percentage is very low compared to all other transit programs,” says study coauthor and astronomer Claire Moutou, also at the University of Aix-Marseille.

The authors point to a discrepancy between their result and a 2011 study done by Timothy Morton and John Johnson at Caltech, who found a false positive rate closer to 5 percent. But comparisons between the two studies might not be so simple, Morton says, noting that the two groups calculated different things. Instead of looking at impostor rates in a specific population of planets, Morton determined the probability that any candidate — plucked from the sea of twinkling candidates — was real. He also excluded data from obvious impostors.

“Everything here is sort of a game of probabilities,” Morton says, pointing to the abundance of candidates. “It will be impossible to confirm them all with observations.”

As for current estimates of billions and billions of planets in the Milky Way, Moutou says those numbers are still valid. “Short period transiting planets are exotic objects, we don’t expect them to be everywhere,” she says. “The potential billion planets are more expected to be small, long-period planets. We didn’t kill those ones, fortunately.”

[Duke of Buckingham]

Invasive mite worsens honeybee viruses
Parasite’s move into Hawaiian islands lets obscure pathogen go big and bad

By Susan Milius
Web edition : Friday, June 8th, 2012

A mite that parasitizes honeybees can turn formerly small-time, local virus strains into widespread, dominant hazards.

As the Varroa destructor mite infiltrated Hawaiian bee colonies from 2007 to 2010, viral infection strength in local bees soared a million-fold, and a once-obscure but nasty strain of deformed wing virus surged to prominence. Even when beekeepers beat back the mite, the newly prominent virus remained abundant. Mite damage plus the virus shorten the lives of bees and can destroy colonies.

So far Hawaiian beekeepers have not reported the swifter, specific malady called colony collapse disorder (SN: 7/28/2007, p. 56), but the ability of the mite — now spreading globally — to reshape viral threats is worrisome, say Stephen J. Martin of the University of Sheffield in England and his colleagues in the June 8 Science.

Honeybees in Hawaii, like the one shown on the native Hawaiian tree "Ohi'a," face worsening risks from deformed wing virus as the Varroa destructor mite spreads across the islands. Credit: Courtesy of Ethel M. Villalobos

[Duke of Buckingham]

Ancient volcanoes destroyed ozone
Eruptions gave off gas that eroded the protective atmospheric layer

By Alexandra Witze
Web edition : Tuesday, June 12th, 2012

SELFOSS, Iceland — Geoscientists have exposed another assault on Earth’s protective ozone layer — not by manufactured chemicals, but by gas ejected in the blasts of huge volcanic eruptions.

A new study shows that volcanic rocks in Nicaragua contain bromine, an element known for speeding ozone’s destruction in the upper atmosphere. When magma erupted to form those rocks, scientists say, it also released huge amounts of bromine into the air — enough to destroy large parts of the ozone layer for several years.

“We have to be aware of this,” says Kirstin Krüger, a meteorologist at the Leibniz Institute of Marine Sciences at the University of Kiel (GEOMAR) in Germany. “Large-scale tropical eruptions have the potential to deplete ozone on a big scale.”

Krüger presented the work, led by GEOMAR volcanologist Steffen Kutterolf, on June 12 at an American Geophysical Union conference on volcanism and the atmosphere.

The scientists studied rocks formed during 13 big Central American eruptions over the past 70,000 years. Volcanoes at tropical latitudes are good at injecting the stuff they erupt into the stratosphere, some 16 kilometers up. When elements such as chlorine and bromine reach that high, they help trigger a series of reactions in which ozone’s three oxygen atoms break apart and recombine with other atoms.

Researchers have previously measured chlorine coming from volcanoes, such as 1991’s Mount Pinatubo eruption in the Philippines, and watched it destroy ozone overhead. But the new work is the first to pin down bromine in such detail. The element is 60 times as efficient as chlorine at destroying ozone, Krüger says.

Kutterolf and his colleagues collected thousands of rock samples both on and offshore, then analyzed bromine concentrations in tiny glass bubbles that formed within the rocks when the magma erupted out of the volcano. The scientists found enough bromine in the bubbles to suggest that 4,000 to 600,000 tons of bromine came out per eruption.

Enough bromine would have made it to the stratosphere to create at least double the ozone-destroying potential seen at the highest modern-day levels, Krüger says. It would have taken three to six years for the chemicals to clear out so that ozone could begin to recover.

It’s still not clear what makes a particular eruption rich in bromine, or whether the bromine would have destroyed ozone locally or globally once aloft.

About three-quarters of atmospheric bromine comes from human-made sources like chlorofluorocarbon chemicals, used in refrigeration and other devices. One-quarter is natural, produced by the sea or by volcanoes. “Wherever it comes from, it will destroy the ozone,” Krüger says. Most human-made ozone-depleting chemicals were phased out by the 1987 Montreal Protocol.

The new study is an important step in better quantifying bromine from present-day eruptions, says Tamsin Mather, a volcanologist at the University of Oxford in England. “If we can apply this to other volcanoes,” she says, “we can really get a handle on how much bromine is coming out.”

Bromine from big volcanic eruptions, like the one that created the Apoyo Caldera in Nicaragua 24,500 years ago, would have destroyed the planet’s protective ozone for years at a stretch. Credit: Steffen Kutterolf/GEOMAR

[zombie67]

Ancient volcanoes destroyed ozone
Eruptions gave off gas that eroded the protective atmospheric layer

By Alexandra Witze

This is obviously a load of crap. We all know that man is the sole source of all things harmful to the environment. Without man, everything would be rainbows and unicorns.

[Crazybob]

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[Duke of Buckingham]

This is obviously a load of crap. We all know that man is the sole source of all things harmful to the environment. Without man, everything would be rainbows and unicorns.

I don't think so Z, no unicorns and some rare rainbows. The world is ruled by the nature of the Universe that we can understand is a very violent place for life.

We have enough proofs, that in the pass, the world lived some several mass extictions, long before man was around. I have a brief history of the major extinctions:

In a landmark paper published in 1982, Jack Sepkoski and David M. Raup identified five mass extinctions. They were originally identified as outliers to a general trend of decreasing extinction rates during the Phanerozoic, but as more stringent statistical tests have been applied to the accumulating data, the "Big Five" cannot be so clearly defined, but rather appear to represent the largest (or some of the largest) of a relatively smooth continuum of extinction events.

1 - Cretaceous–Paleogene extinction event (End Cretaceous, K-T extinction, or K-Pg extinction): 65.5 Ma at the Cretaceous.Maastrichtian-Paleogene.Danian transition interval. The K–T event is now officially called the Cretaceous–Paleogene (or K–Pg) extinction event in place of Cretaceous-Tertiary. About 17% of all families, 50% of all genera and 75% of species became extinct. In the seas it reduced the percentage of sessile animals to about 33%. The majority of non-avian dinosaurs became extinct during that time. The boundary event was severe with a significant amount of variability in the rate of extinction between and among different clades. Mammals and birds emerged as dominant land vertebrates in the age of new life.
2 - Triassic–Jurassic extinction event (End Triassic): 205 Ma at the Triassic-Jurassic transition. About 23% of all families and 48% of all genera (20% of marine families and 55% of marine genera) went extinct. Most non-dinosaurian archosaurs, most therapsids, and most of the large amphibians were eliminated, leaving dinosaurs with little terrestrial competition. Non-dinosaurian archosaurs continued to dominate aquatic environments, while non-archosaurian diapsids continued to dominate marine environments. The Temnospondyl lineage of large amphibians also survived until the Cretaceous in Australia (e.g., Koolasuchus).
3 - Permian–Triassic extinction event (End Permian): 251 Ma at the Permian-Triassic transition. Earth's largest extinction killed 57% of all families and 83% of all genera (53% of marine families, 84% of marine genera, about 96% of all marine species and an estimated 70% of land species) including insects. The evidence of plants is less clear, but new taxa became dominant after the extinction. The "Great Dying" had enormous evolutionary significance: on land, it ended the primacy of mammal-like reptiles. The recovery of vertebrates took 30 million years, but the vacant niches created the opportunity for archosaurs to become ascendant. In the seas, the percentage of animals that were sessile dropped from 67% to 50%. The whole late Permian was a difficult time for at least marine life, even before the "Great Dying".
4 - Late Devonian extinction: 375–360 Ma near the Devonian-Carboniferous transition. At the end of the Frasnian Age in the later part(s) of the Devonian Period, a prolonged series of extinctions eliminated about 19% of all families, 50% of all genera and 70% of all species. This extinction event lasted perhaps as long as 20 Ma, and there is evidence for a series of extinction pulses within this period.
5 - Ordovician–Silurian extinction event (End Ordovician or O-S): 450–440 Ma at the Ordovician-Silurian transition. Two events occurred that killed off 27% of all families and 57% of all genera. Together they are ranked by many scientists as the second largest of the five major extinctions in Earth's history in terms of percentage of genera that went extinct.

Despite the popularization of these five events, there is no fine line separating them from other extinction events; indeed, using different methods of calculating an extinction's impact can lead to other events featuring in the top five.

The older the fossil record gets, the more difficult it is to read. This is because:

Older fossils are harder to find because they are usually buried at a considerable depth in the rock.
Dating older fossils is more difficult.
Productive fossil beds are researched more than unproductive ones, therefore leaving certain periods unresearched.
Prehistoric environmental disturbances can disturb the deposition process.
The preservation of fossils varies on land, but marine fossils tend to be better preserved than their sought after land-based counterparts.

It has been suggested that the apparent variations in marine biodiversity may actually be an artifact, with abundance estimates directly related to quantity of rock available for sampling from different time periods. However, statistical analysis shows that this can only account for 50% of the observed pattern, and other evidence (such as fungal spikes)[clarification needed] provides reassurance that most widely accepted extinction events are indeed real. A quantification of the rock exposure of Western Europe does indicate that many of the minor events for which a biological explanation has been sought are most readily explained by sampling bias.

And we had some lesser extinctions also:

Quaternary extinction event 50 ka to now
Neogene 23.03 Middle Miocene disruption 14.5 Ma Nördlinger Ries bolide impact? Volcanoes in African Rift Valley
Eocene–Oligocene extinction event 33.9 Ma Volcanoes? Chesapeake Bay and Popigai crater bolide impacts?
Cretaceous 145.5 Aptian extinction 117 Ma Rahjamal Traps volcanism episode in Bengal?
End-Jurassic extinction 145.5 Ma
Jurassic 199.6 Toarcian turnover 183 Ma
Permian 299 Olson's Extinction 270 Ma
Carboniferous 359.2 Carboniferous Rainforest Collapse 318 Ma Climate change
End Silurian 416 Ma
Lau event 420 Ma
Mulde event 424 Ma Global drop in sea level?
Silurian 443.7 Ireviken event 428 Ma Deep-ocean anoxia?
Cambrian–Ordovician extinction event 488 Ma Glaciation? Depletion of oxygen in marine waters?
Dresbachian 502 Ma
Cambrian 542 End Botomian extinction event 517 Ma
Precambrian 4567.17 End-Ediacaran extinction 542 Ma Ocean anoxia?

So as you can see, man it is not the only danger to life Z. We must have some protection to keep the life going but we know that for shure or wouldn't talk about extinctions on a dayly basis.

Some say the next will come on 21st December of this year. I say they didn't read the Maia, Aztecs and Inca hystory as they should. They were expecting their gods to come back, not the destruction of the world. The only surprise that could happen on that day was the ETs showing up in some places. The Maya codices are listed in here with a brief description of each but a good search and some studies could help the understanding of this fascinating culture.

http://en.wikipedia.org/wiki/Maya_codices

[Duke of Buckingham]

Today at 6:30 AM Lisbon time the Mars Rover should land.

Fingers crossed.

[Duke of Buckingham]

Wheels down, Mars rover takes in the view
Curiosity lands safely, begins transmitting images

By Nadia Drake
Web edition : Monday, August 6th, 2012

PASADENA, Calif. — Curiosity is alive and well on Mars.

After a daring, well-documented descent into Gale Crater, NASA’s flagship rover came to rest about 6.5 kilometers from the base of Mount Sharp and 28 kilometers from the crater’s northwest rim.

For the next few weeks, Mars’ newest inhabitant will stay put, easing its many instruments into action while snapping photos of its environs. For now, it appears that Curiosity — and all the instruments aboard — are healthy.

“There’s a lot ahead of us, but so far we are just ecstatic about the performance of the vehicle,” said Jennifer Trosper, Mars Science Laboratory mission manager at JPL.

Though Curiosity won’t be stretching its wheels for a few weeks, the rover and its orbiting cousins are busy supplying scientists back home with pictures of the terrifying, seven-minute journey to the crater floor.


From 6.5 kilometers away, Mount Sharp looms large on Curiosity’s Martian horizon. Eventually, the rover will begin climbing this mountain and reading a history of Mars’ ancient environments in its layers. Credit: NASA, JPL-Caltech

“We’re going to make sure that we’re firing on all cylinders before we blaze out across the plains there,” said project scientist John Grotzinger of Caltech.

On August 6, a camera mounted on the rover’s belly returned a series of thumbnail images taken during the plunge into Gale Crater. Strung together into an animation, the 297 images span the descent, beginning with the spacecraft’s heat shield falling away and ending with billowing dust clouds kicked up during the rover’s retrorocket-powered, sky crane–mediated touchdown. A full-resolution video of the descent is expected in a few weeks, said Mike Malin, principal investigator for the Mars Descent Imager and president and chief scientist at Malin Space Sciences Systems in San Diego.

The belly-cam wasn’t the only instrument taking pictures during the rover’s daring skydive into Gale Crater.

An orbiting eye was also watching. From 340 kilometers away, the HiRISE camera aboard the Mars Reconnaissance Orbiter shot an image that shows the rover parachuting into the crater one minute before touchdown. “This was a great, great shot,” said JPL’s Sarah Milkovich, HiRISE investigation scientist. Also in the image: The spacecraft’s heat shield, falling toward Mars. Capturing the image required wrangling the orbiter into place and aiming the camera toward Curiosity, a maneuver the HiRISE team estimated had a 60 percent chance of succeeding.

Curiosity has also sent postcards from its new home in Gale Crater.

The first photo from the surface arrived late in the California evening on August 5, just after the landing, and shows the rover’s rear wheel in front of a field of gravel, with the crater rim rising in the background. “I think that is the best picture of Mars that I’ve ever seen,” Grotzinger said. He notes that it appears as though Curiosity is parked near the edge of an area where flowing water once swept materials over the crater wall and into the basin. “This [process] is bringing materials in from the rim, which is not our destination,” he said. “But we’re getting a free sample without having to drive over there, potentially.”

A later photo from the front of the rover shows Mount Sharp looming in the distance, a massive pile of sediments the likes of which doesn’t exist anywhere on Earth. Unlike large mountains on Earth, Mount Sharp appears to have formed as water and wind filled in the crater, depositing the layered sediments that created the peak. Then, erosion created a moat-like shape, leaving the mountain protruding from the middle of the crater.

Today, Mount Sharp resembles several places on Earth, but with the story of Mars’ environmental history tucked into its layers and awaiting Curiosity’s eager reading.

Even with Mount Sharp calling from the horizon and tantalizing scientific treats underfoot, the rover’s team will take its time deciding where to send Curiosity first. “Be patient with us, please,” said project manager Pete Theisinger after touchdown. “Because we will be patient with Curiosity.”


NASA’s Mars Reconnaissance Orbiter captured Curiosity parachuting into Gale Crater (box, and inset). At this stage in the descent, Curiosity is about a minute from touchdown. Credit: NASA, JPL-Caltech, Univ. of Arizona