Wednesday, 30 September 2009

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Hubble Catches Galaxies Stripping — Ram Pressure Stripping, That Is

Posted: 30 Sep 2009 09:04 AM PDT


Galaxies speeding through clusters of their neighbors wereimaged by the Hubble Space Telescope being stripped of their gas.

NGC 4522, the galaxy pictured above, is traveling at 6.2 million milesper hour, astronomers estimate. It's about 60 million light-years away in the Virgo cluster. The bright blue areas to the right and left are star-forming regions.

Unlike our own Milky Way galaxy with its delicate spiral arms, fast-moving galaxies like NGC 4522 get deformed by the strong winds generated by their movement. The process is known as "ram pressure stripping" and it's analogous to what would happen were you to hold a dandelion parachute ball out a car window. The lighter parts get stripped away.

Galaxy NGC 4402, pictured below, shows off the convex gas and dust disc that is characteristic of galaxies undergoing ram pressure stripping. The hot gas between galaxies in a cluster (known as the intra-cluster medium) actually sweeps the gas away, creating the odd shape in the process.

The images were taken by the Advanced Camera for Surveys instrument before it suffered a power failure in 2007. The images were recovered when astronauts restored the unit in May of this year on the last Hubble Servicing Mission. Both are deep enough to show distant background galaxies.

High-res version of the top photo (40 MB): NGC 4522
High-res version of the bottom photo (29 MB): NGC 4402


Images: NASA/ESA

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WiSci 2.0: Alexis Madrigal's Twitter, Google Reader feed, and green tech history research site; Wired Science on Twitter and Facebook.

Weird, Rare Clouds and the Physics Behind Them

Posted: 29 Sep 2009 05:06 PM PDT

<< previous image | next image >>

In August, we posted a photograph of some odd, rare clouds known as Morning Glory clouds without providing an explanation for how they form. In response to reader interest, we followed up with meteorologist Roger Smith of the University of Munich, who has studied their formation.

"Over the years we've developed a good understanding of them," Smith said. "It's no longer a mystery, but still very spectacular."

The Morning Glory phenomenon is the result of the particular configuration of the land and sea on the Cape York Peninsula, in a remote part of Australia. The peninsula tapers off from about 350 miles wide to 60 miles as it extends north between the Gulf of Carpentaria to the west and the Coral Sea to the east. The easterly trade winds push the sea breeze across the peninsula during the daytime, which meets the sea breeze from the west coast in the late evening. The collision produces a wave disturbance moving inland to the southwest that is a key part of the cloud formation.

As moist sea air is lifted to the crest of the waves, it cools and condensation forms a cloud. Sometimes there is just one wave, but Smith has seen as many as 10 together in a series.

"If you look at the clouds, it looks as if they are rolling backwards," Smith said. "But in fact the clouds are continuously formed at the leading edge and continuously eroded at the trailing edge. That gives a rolling appearance."

These clouds do occur elsewhere, including Munich, where they form about once in a decade. Cape York is unique because they happen regularly in the fall above the small town of Burketown. And they can also be particularly impressive there as well, growing up to 600 miles long. Pilots fly into the area every year, hoping to see the intriguing clouds.

Not many scientists study them, or really any weird clouds, because their very rarity makes them relatively unimportant for studying precipitation or climate. So, oftentimes, their formation is poorly understood.

"It's hard to get funding to study something that's neat looking," said cloud physicist Patrick Chuang of the University of California, Santa Cruz.

On the following pages, we've gathered photos of some of the strangest, most beautiful cloud types and asked scientists to help us understand how they form.

Images: Above: Ulliver/Wikimedia Commons. Below: Image: Mick Petroff/APOD


T. rex Bite Marks Actually Festering Infections

Posted: 29 Sep 2009 01:27 PM PDT


The biggest problem for Tyrannosaurus rex could have been a single-celled parasite in a paleolithic turn on the tiny-fells-mighty, War of the Worlds story.

A relative of lowly Trichomonas, a microbe commonly found today in pigeons, may have killed off Sue, the famous T. rex skeleton at the American Museum of Natural History, and many other tyrannosaurids, too.

Paleontologist Ewan Wolff of the University of Wisconsin-Madison and colleagues use evidence from modern predatory bird species to argue that the protozoan parasite could have formed lesions along the tyrannosaur mandible, eroding the bone away.

In some cases, the illness might have been bad enough to prevent the animals from feeding, leading to their death from starvation, and creating telltale holes in the jaws of the great beasts.

"I think it's very tempting when you see a hole in a bone to say it's bite marks, but there are innumerable disease you could list that cause holes in bones that have nothing to do with bite wounds," said Ewan Wolff, lead author of a new paper describing the work published Sept. 29 in PLoS One.


There are three pieces of evidence against the bite-wound hypothesis, Wolff said. First, the holes are generally nicely circular or ovoid, not obviously tooth-shaped. Second, dinosaurs obviously had many teeth, not just one, and the holes don't seem to come in groups. Third, there are no smaller marks or scrapes on the bone surrounding the holes.

"We're definitely familiar with what predation traces look like from tooth marks in tyrannosaurus," Wolff said. "And this is not it."

Furthermore, they found evidence in predatory birds that trichomonosis can cause holes in the mandible that look quite similar to those found in nine tyrannosaurid specimens.

The disease could have been passed to dinosaurs from their prey or from tyrannosaur to tyrannosaur during combat, mating, or cannibalism.

"Head or face-biting behavior relating to intraspecific territoriality, social dominance, courtship, feeding or some other unknown aspect of tyrannosaurid behavior would have provided the ideal mechanism for the transmission of this trichomonosis-like disease," Wolff and colleagues wrote.

Other researchers, notably dinosaur anatomy expert Elizabeth Rega of Western University of Health Sciences in Pomona, California, have argued the holes were disease-induced. But Rega's culprit was the bacteria, actinomycosis.

Wolff, however, argued that much of the damage that actinomycosis causes in humans is due to puss. Birds don't actually create puss, and the same was likely true of dinosaurs. It's not part of the avian immune response. Instead, birds coat invading organisms with a fibrous protein.

"So instead of getting puss, you get this very cheesy inflammatory area," Wolff said. "You get chronic infection that just doesn't go away."

He said that the actinomycosis-trichomonosis debate showed how his team's approach differed from other paleopathologists.

"In the past, a lot of comparisons of paleopathological specimens have been made to humans or domesticated animals," Wolff said, instead of with dinosaurs' closer relatives, birds and reptiles. "It makes a lot of sense to look at animals that share a close evolutionary relationship to each other and the diseases that they have. The approach in this article is to do just that and that's relatively novel in the paleopathological community."

Still, not everyone is sold on the new idea about Sue's holey jaw.

"My suspicion is that it's not valid," said Bruce Rothschild, a medical doctor and paleopathologist at the University of Kansas.

Rothschild said the holes in Sue's jaw look a lot like the marks made by trepanation — the practice of puncturing of the skull — in ancient humans.

"I'm not saying it was trepanation," Rothschild said. "I'm saying it was a bite."

And he disputed that the modern examples of presumed trichomonas jaw holes matched up "exactly" with the tyrannosaur fossil holes.

"To me, it's not exactly the same," he said.

Rothschild said that the tyrannosaur fossils showed just "a hole with simple infilling," without the more complex features associated with lesions.

What might be next is looking at dinosaur specimens for other signs of starvation, suggested Thomas Holtz, a tyrannosaur specialist at the University of Maryland.

"I don't know if you'd see maybe bone loss as a sign of starvation," Holtz said.

Wolff said his team could follow up with exactly that type of observation. Another line of inquiry could run in the molecular direction, trying to determine if parasites like trichomonas did in fact exist 65 millions of years ago.

"I don't know to what degree anyone can confirm that this particular group of organisms were around during the Cretaceous," Holtz said. "We don't have a fossil record for them."

Image: Pex Rex. Chris Glen/University of Queensland

See Also:

WiSci 2.0: Alexis Madrigal's Twitter, Google Reader feed, and green tech history research site; Wired Science on Twitter and Facebook.

Tuesday, 29 September 2009

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Megafauna Extinctions Not Entirely Humans’ Fault

Posted: 29 Sep 2009 10:37 AM PDT


BRISTOL, England — Studies that have mostly blamed the arrival of humans for die-offs among Australia's large mammals 50,000 years ago missed the role played by a changing climate, new research suggests.

sciencenewsMost assessments of Australian extinctions have used evidence gathered at sites that typically include fossils from only one narrow interval of time, Gilbert Price, a vertebrate paleontologist at the University of Queensland in St. Lucia, Australia, reported September 23 here at the meeting of the Society of Vertebrate Paleontology. But he and his colleagues have analyzed fossils of creatures both large and small from Darling Downs, a site in eastern Australia with a fossil record that extends from about 120,000 to about 55,000 years ago. In all, the team has tallied about 70 species that lived nearby at some point during that interval.

The data doesn't support a previously proposed human-only cause for Australian megafaunal extinctions, Price noted. From strata deposited about 120,000 years ago, the researchers recovered the remains of 15 species of large mammals. About 90,000 years ago, only eight species of large mammals lived there. By 55,000 years ago, still several millennia before humans arrived in the area, only four large mammal species remained.

That long-term drop in diversity also appeared among small creatures, and the types of species that disappeared suggest climate change played a role, Price said. Sediments deposited from 120,000 to 90,000 years ago contain the fossils of rodents, frogs and land snails as well as large mammals, suggesting that the surrounding area was a patchwork of woodlands, vine-choked thickets and open grasslands. By 55,000 years ago, however, many of the wet-loving and forest-adapted species had largely disappeared, signaling a transition to drier, more open conditions.

The new findings don't pin the blame for Australia's final spate of mammal extinctions on either climate change or human presence, Price cautioned. The long-term trend in species diversity at Darling Downs does hint, however, that climate change caused some species to die out. And the changes may have reduced the populations of other species enough that human arrival easily tipped them over the edge to extinction.

Image: Gilbert Price at Darling Downs in 2006. / Erika Fish, QUT Marketing & Communication

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Genetically Modifying Songbirds to Study Human Brain Growth

Posted: 29 Sep 2009 10:03 AM PDT


By genetically modifying the brains of songbirds for the first time, scientists may have a devised useful new tool for studying neurological growth and healing in humans.

"Songbirds have become a classic tool for studying vocal learning and neuron replacement. This will bring those two topics into the molecular age," said neuroscientist Fernando Nottebohm of Rockefeller University, author of a study September 28 in the Proceedings of the National Academy of Sciences.

Nottebohm's team successfully added fluorescent protein-producing genes to 23 zebra finches, a feat that — in the age of pet dogs clones and Alba the glow bunny — may not seem extraordinarily noteworthy at first glance. But unlike many other animals, including chickens and quail, songbirds have been remarkably hard to genetically modify. That's frustrating to scientists, who study the birds' ability to change their songs according to setting and experience.

That ability, known as vocal learning, is believed to rely on a version of the same neurological systems that eventually allowed a clever branch of the primate tree to acquire language and become human. It makes the birds an important model of human learning, language and neural development.

gmsongbird-nNottebohm rose to fame during the 1990s, after finding that songbirds grew new brain cells in order to learn seasonal songs. That ran contrary to the conventional neurological truth of adults having a set number of brain cells. After being dismissed as fantasy, the ability has been found throughout the animal kingdom, including in humans.

All this has made songbirds as potentially important to understanding the growth of our brains as mice are to understanding our bodies. And now, just as it's possible to genetically modify mice, scientists might do the same in songbirds.

"When you talk about underlying mechanisms at the cellular level, you have to be able to manipulate genes. Otherwise, all your hypotheses are untestable," said Nottebohm. "It will open the door to a whole new generation of work on vocal learning that has not been possible."

Nottebohm's team injected 256 zebra finch embryos with viruses that traveled into the birds' genomes and inserted a gene that produced a fluorescent protein. When the birds hatched, cells containing the protein glowed.

The method is still in proof-of-principle stages, requiring between 10 and 20 injections per embryo. That repeated trauma could explain why just 23 of the embryos hatched, and only three passed on the genetic changes to their offspring.

"There's got to be a better way. We're delighted that we got it that far, but as we come to understand how this works, we would like to bring up the efficiency," said Nottebohm.

However, the importance of the technique is not in those early numbers, but the the possibility they represent, he said.

"We can test hypotheses that might explain how and why cells in the brain are replaced," said Nottebohm.

Images: 1. Scharff Lab 2. PNAS

See Also:

Citation: "Transgenic songbirds: An opportunity to develop
a genetic model for vocal learning." By R. J. Agatea, B. B. Scott, B. Haripal, C. Lois, and F. Nottebohm. Proceedings of the National Academy of Sciences, Vol. 106, No. 39. September 29, 2009.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points.

Superheavy Element 114 Finally Recreated

Posted: 29 Sep 2009 09:48 AM PDT


By firing calcium isotopes into a plutonium target inside a particle accelerator, scientists at Lawrence Berkeley National Laboratory have finally confirmed the Russian discovery of the superheavy element 114.

It wasn't easy. It took more than a week of running the experiment to generate a measly two atoms of the stuff, which they reported in Physical Review Letters last week. It's basic science at the outer limits of matter.

"We're learning the limits of nuclei," said Ken Gregorich, a nuclear physicist at LBL. "How many protons can you pack into a nucleus before it falls apart?"

Uranium, which has 92 protons in its nucleus, is the heaviest element found in substantial quantities in nature. The first man-made "transuranic" elements like plutonium were discovered and synthesized during the 1940s in the run-up to the creation of nuclear weapons. Since then, it's gotten harder and harder to produce new elements, but scientists have kept at it. One reason is they hypothesized that certain isotopes of very heavy particles might exist in an "island of stability" that would allow them to stick around longer than the fractions of a second most synthetic elements last.

So, it was with great excitement that scientists received the news in early 1999 that the Joint Institute for Nuclear Research in Dubna appeared to have discovered Element 114 — and it lasted for whole seconds.

"It's fantastically important work," Neil Rowley of the Institute for Subatomic Research in Strasbourg, France told New Scientist in 1999.

Glenn Seaborg, Nobel Prize winner, adviser to presidents, and a big advocate of the island theory of superheavy elements, was even delivered the news of the Russian discovery on his death bed by an old friend.

"The term 'magic' was continually used — Seaborg and others spoke of a magic ridge, a magic mountain and a magic island of elements," wrote Oliver Sachs of the search for the island. "This vision came to haunt the imagination of physicists the world over. Whether or not it was scientifically important, it became psychologically imperative to reach, or at least to sight, this magic territory."

After decades of swimming through particle accelerator data, the island had been reached. It was tremendously big news.

Or so they thought.

As the years went by, the Russian team published a series of papers about Element 114, but other teams couldn't confirm their initial discovery of the extraordinarily long-lived particle. There were two reasons for this. One, the experimental apparatus required to check the findings were only available in a small number of labs around the world. Two, it appears the Russians were wrong.

"I think back in '99 they were learning how to do this and I think they had a random correlation of unrelated events that appeared to be Element 114," Gregorich said.

It's not that they didn't eventually discover Element 114. They did. It's just that their first observation, the most exciting one, turned out to be incorrect. In four separate publications from 2000 to 2004, they came up with better data, and those are the observations that Gregorich said his lab has confirmed.

And the island of stability? It is actually there, Gregorich said, but its effects are less pronounced than (at least) Seaborg hoped. The particular combinations of protons and neutrons do yield longer lasting elements, just not … magic ones.

"Our results and the Dubna results show that there is some stability there," Gregorich said. "If we didn't have extra stability due to the shell effects, these things would decay faster than we could ever detect them with lifetimes on the order of 10-20 seconds rather than 10-1 seconds."

The search, though, for a more perfect superheavy element does go on.

"There are still predictions that if you could use more neutron-rich projectiles, if you could produce these elements but with more neutrons, some of them would be pretty long lived," he said.

Unfortunately, the particle accelerators in operation and currently planned won't reach the power necessary to get to create the theoretically most stable elements.

"The present and next generation of radioactive beam machines don't have high enough beam intensities," Gregorich said. "The technology doesn't exist today but it might in another 20 or 30 years."

Image: The Berkeley Gas-filled Separator, the detector used in the experiment, in situ.
Ken Gregorich/LBL.

See Also:

WiSci 2.0: Alexis Madrigal's Twitter, Google Reader feed, and green tech history research site; Wired Science on Twitter and Facebook.

Electric Fish Turn Down Charge for Energy Efficiency

Posted: 28 Sep 2009 05:00 PM PDT


Fish that use electric fields to sense their environments dim their signals to save energy during the day when they are resting.

Sternopygus macrurus, a South American river fish, is a natural practitioner of energy efficiency. It can reshape the charged-molecule channels in its electricity-producing cells to tone down its electrical signature within a matter of minutes.

"This is a really expensive signal to produce. The fish is using up a lot of its energy budget," said neurobiologist Michael Markham at the University of Texas at Austin, lead author of a paper in PLoS Biology on the fish. "These animals are saving energy by reducing the strength of the signal when they are not active."

Thousands of fish and other oceanic creatures use electrical fields to help them perceive their environments. The most famous is the electric eel, which a colleague of Markham's termed "a frog with a cattle prod attached," but most animals use the electrical signals in more subtle ways.

The fish's standard electrical signal runs at 100 hertz; if you turn the electrical signal into sound, it sounds like a high whine. In laboratory experiments, the fish can detect tiny bugs half a centimeter wide and easily navigate obstacles by detecting the changes the objects cause in the electrical field.

electric-organ1Other fish put out different types of electrical fields, some of which vary a lot more. Markham's team chose S. macrurus specifically because its discharge is fairly regular.

All fish generate electricity with a specialized type of cell called an electrocyte. These cells can generate current by manipulating the amount of charged sodium and potassium ions that they allow to flow into and out of themselves. An electrical current propagates on the membrane of the cell as a result. Thousands of cells combine to generate the 5 millivolts per centimeter electrical field the fish uses. By using fewer sodium channels, the signal gets dimmed and energy is conserved.

"The wave form of the electric signal changes and at the level of the individual cell, it is changing its discharge," Markham said. "This is the first time in a vertebrate animal that you can show such a clear connection between an animal's behavior and the changes at the molecular level."

For Markham, the system is interesting because the ways cells reshape their membranes — scientists call the process ion channel trafficking — are very similar to the ones that our hearts and nervous systems use.

The same molecular machinery that drives our nervous system, muscles and heart has evolved into an organ just to produce electricity, he said. The specialized organ, then, acts as a kind of biological laboratory for evolutionary experiments with electricity production.

"If there is a slight mutation in the ion channels in your heart, that's very likely to be a fatal mutation," Markham said. "The electric organ from an evolutionary standpoint is a much more forgiving place for experimentation."

In the future, they hope to use their research on ion channels to better understand the kinds of electrical malfunctions that cause disorders like epilepsy.

"There's a kind of gee whiz interest factor to working with these fish, but obviously, we're pursuing a bigger agenda," Markham said.

See Also:

WiSci 2.0: Alexis Madrigal's Twitter, Google Reader feed, and green tech history research site; Wired Science on Twitter and Facebook.

Quantum Entanglement Visible to the Naked Eye

Posted: 28 Sep 2009 02:41 PM PDT


By linking the electrical currents of two superconductors large enough to be seen with the naked eye, researchers have extended the domain of observable quantum effects. Billions of flowing electrons in the superconductors can collectively exhibit a weird quantum property called entanglement, usually confined to the realm of tiny particles, scientists report in the September 24 Nature.

sciencenews"It's an exciting piece of work," comments physicist Steven Girvin of Yale University. "People are interested in pushing the boundaries of quantum mechanics."

Entanglement is one of the strangest consequences of quantum mechanics. After interacting in a certain way, objects become mysteriously linked, or entangled, so that what happens to one seems to affect the fate of the other. For the most part, researchers have only found signs of entanglement between tiny particles, such as ions, atoms and photons.

John Martinis and colleagues at the University of California, Santa Barbara looked for entanglement between two superconductors, each less than a millimeter across. These superconducting circuits, made of aluminum, were separated by a few millimeters on an electronic chip. At low temperatures, electrons in the superconductors flow collectively, unfettered by resistance.

Despite each superconductor's relatively large size, the electrons within move together in a naturally coherent way. "There are very few moving parts, so to speak," Girvin says, which helped the scientists spot evidence of entanglement. "It's a general fact that the larger an object is, the more classical it is in its behavior, and the more difficult it is to see quantum mechanical effects."

In the new study, researchers used a microwave pulse to attempt to entangle the electrical currents of the two superconductors. If the currents were quantum-mechanically linked, one current would flow clockwise at the time of measurement (assigned a value of 0), while the other would flow counterclockwise when measured (assigned a value of 1), Martinis says. On the other hand, the currents' directions would be completely independent of each other if everyday, classical physics were at work.

After attempting to entangle the superconducting circuits, Martinis and his team measured the directions of the currents 34.1 million times. When one current flowed clockwise (measured as a 0), the team found, the other flowed counterclockwise (measured as a 1) with very high probability. So the two were linked in a way that only quantum mechanics could explain.

"It has to be in this weird quantum state for you to get those particular probabilities that we measure," Martinis says. "The percentages of those different things are not something that you can classically predict."

Finding entanglement between superconductors is "a fairly important milestone," comments Anthony Leggett of the University of Illinois at Urbana-Champaign. The new study "does seem to be rather unambiguous evidence for entanglement."

Such entangled superconductors might be used as a component in a powerful quantum computer, Leggett says. "People are very interested in the possibility of building a quantum computer," and these kinds of systems may be quite good for that, he says.

Martinis says that the technology for building advanced electrical circuits may be used to build quantum circuits, too. "The hope is that since we know how to put together integrated circuits in complex ways, that maybe we can make very complex quantum circuits in the same way," he says.

He cautions, though, that a good quantum computer is a long way off. Researchers still need to find a way to make entangled superconducting circuits last longer. And a good quantum computer would need more than two circuits. Martinis says his group will try to entangle three and four such circuits next.

In addition to providing technological advances, the new results add to the debate over where to draw the line between quantum mechanics and the everyday physics that governs large-scale phenomena. Researchers want to know how far quantum weirdness can go.

"It's interesting to test quantum mechanics on a large scale," Girvin says. "Do things look classical on large scales because there's something wrong with quantum mechanics? Personally, I think that's wrong, but one never knows."

Image: Erik Lucero

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Dark Matter Hunters Construct a New Weapon

Posted: 28 Sep 2009 01:54 PM PDT


That dark matter has never been found is no deterrent to the physicists who are looking for it.

"Even if we don't know what dark matter is, we know how it must act," said Eduardo Abancens, a physicist at Spain's University of Zaragoza and designer of a prototype dark matter detector.

According to physicists, only around five percent of what makes up the universe can presently be detected. The existence of dark matter is inferred from the behavior of faraway galaxies, which move in ways that can only be explained by a gravitational pull caused by more mass than can be seen. They estimate dark matter represents around 20 percent of the universe, with the other 75 percent made up of dark energy, a repulsive force that is causing the universe to expand at an ever-quickening pace.

At the heart of Abancens' team's detector, which is called a scintillating bolometer and resembles a prop from The Golden Compass, is a crystal so pure it can conduct the energy ostensibly generated when a particle of dark matter strikes the nucleus of one of its atoms.

To prevent interference by cosmic rays, the bolometer is sheathed in lead and kept underground, under half a mile of rock. It's also frozen to near-absolute zero, the temperature at which all motion stops. At the edge of absolute zero, it's possible to measure expected changes of a few millionths of a degree Fahrenheit.

Researchers like Abancens call this "a high heat signal."

As described in a paper published in the August Optical Materials and released online Friday, the bolometer is currently able to distinguish between the vibrations produced by trembling nuclei and spinning electrons. Abancens said it could be operational in five years.

But in order for the bolometer to work reliably, it needs to become even more sensitive, and maintain that sensitivity as it's scaled up from the 46-gram prototype to a half-ton working model, said Rick Gaitskell, a Brown University physicist who was not involved in the research.

At near-absolute zero, conducting research is "quite challenging," said Gaitskell, who spent a decade trying to make detection systems work at that temperature.

"Now we're using using liquid xenon. It's relatively warm, only minus 150 degrees Fahrenheit," he said. "You can nearly get to that in an industrial-strength refrigerator."

See Also:

Citation: "A BGO scintillating bolometer as dark matter detector prototype." By N. Coron, E. García, J. Gironnet, J. Leblanc, P. de Marcillac, M. Martínez, Y. Ortigoza, A. Ortiz de Solórzano, C. Pobes, J. Puimedón, T. Redon, M.L. Sarsa, L. Torres and J.A. Villar. Optical Materials, Vol. 31 Issue 10, August 2009.

Image: The blue glow comes from the photographer's flash.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points.

Zoom In on Lagoon Nebula with Super-High-Res Image

Posted: 28 Sep 2009 10:14 AM PDT


A huge new image of the Lagoon Nebula, covering an area of the sky eight times larger than the full moon, has been released by the European Southern Observatory.

Located four to five thousand light-years away in the direction of Sagittarius, the nebula is a cloud of dust and gas about 100 light-years across. Bright, star-forming clusters can be seen scattered throughout the reddish nebula, which acquires its color from small particles that scatter white light.

The full 668-megabyte TIFF is available, and an online zoomable version, too.

The image is the third in a "trilogy" plotted and executed by the ESO for the International Year of Astronomy 2009. The previous GigaGalazy Zoom images showcased the best the unaided human eye and an amateur telescope could do. The latest photo steps up to the pro level by using the 67-million-pixel Wide Field Imager attached to the 2.2-meter telescope at the La Silla Observatory in the Atacama desert of Chile.

See Also:

WiSci 2.0: Alexis Madrigal's Twitter, Google Reader feed, and green tech history research site; Wired Science on Twitter and Facebook.

Saturday, 26 September 2009

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Reader Photo Gallery: Awesome DIY Astronomy

Posted: 25 Sep 2009 03:30 PM PDT


Wired Science has some great amateur astronomers among our readers and followers. Our first reader-contributed space photo was an eerie glowing space bubble. We asked on Twitter and in a post for more of your photos of space, and we got some beautiful images in return. Thanks!

Above: Elias Jordan sent us this superb shot of the Pelican Nebula that he took in June with an astronomical camera (SBIG STL11000M) and a telescope (Takahashi FRC 300). The exposure time was 114 minutes. How awesome is it that someone can get an image this nice of something 2,000 light years away, basically from a backyard in New Mexico?

Below: Arran Hill shared this terrific image of the Pacman Nebula, more officially known as NGC 281. This star-forming region 10,000 light years away got its nickname from its overall shape, which resembles an open-mouthed Pacman. This image required 69 15-minute exposures, for a total of more than 17 hours divided among three different filters. Sulfur gas appears reddish, hydrogen is green and oxygen is blue.

"This gives a false color," Hill wrote in an e-mail. "But by using it, more delicate and subtle structure is revealed in the image."

If you've got some super space shots you'd like to see featured on Wired Science, let us know by e-mail or on Twitter @wiredscience.

See more images by all three of our reader astrophotographers on the next page.


More images on the next page.

Four-Winged Fossil Bridges Bird-Dinosaur Gap

Posted: 25 Sep 2009 12:10 PM PDT


BRISTOL, England — A newly described, profusely feathered dinosaur may give lift to scientists' understanding of bird and flight evolution, researchers report. The lithe creature, which stood about 28 centimeters tall at the hip, is the oldest known to have sported feathers and is estimated to be between 1 million and 11 million years older than Archaeopteryx, the first known bird.

sciencenewsSeveral fossils of the creature, which has been dubbed Anchiornis huxleyi, have been unearthed in northeastern China, Xing Xu reported September 25 at the annual meeting of the Society of Vertebrate Paleontology. The strata that contained those feathered fossils were laid down as sediments between 151 million and 161 million years ago, he and his colleagues note online September 24 in Nature.

Two types of feather adorn the creature, said Xu, of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. One kind, commonly referred to as "dino-fuzz," resembles a frayed bundle of filaments. The other type, similar in overall structure to the feathers of modern-day birds, consists of small filaments that branch from a larger shaft-like filament.

birdcartoonThe dino-fuzz decorates the creature's head and neck. About two dozen of the shafted feathers adorn each forelimb, and a similar number embellish each lower leg and foot, the researchers report. Unlike most feathered dinosaurs described previously, which have the longest forelimb feathers near the tip of the limb,
Anchiornis' longest forelimb feathers are on the wrist, Xu said. Feathers on the legs and feet appear to have overlapped each other, creating aerodynamic surfaces that would have, in essence, given Anchiornis a wing on each of its four limbs. A similar configuration has been seen in other feathered dinosaurs, including Microraptor (SN: 1/27/07, p. 53) and Archaeopteryx (SN: 9/23/06, p. 197).

With so many species with this arrangement, the four-winged configuration must have been an important phase in the evolutionary transition from dinosaurs to birds, says James M. Clark, a vertebrate paleontologist at George Washington University in Washington, D.C.

Larry D. Martin, a paleontologist at the University of Kansas in Lawrence, agrees. The profuse plumage on Anchiornis' feet, he notes, also suggests that the creature was a tree dweller, bolstering the notion that flight developed from the trees down, not from the ground up. "No dinosaur could walk well with feathers on its feet like that," he adds.

Many scientists scoff at the suggestion that the filamentary structures found on some dinosaurs, especially those unearthed in China in recent years, represent nascent feathers. But those creatures lived many millions of years after Archaeopteryx, which had feathers indistinguishable from those on modern-day birds. The new find is important because it undoubtedly includes the oldest known feathers on any creature, says Mike Benton, a vertebrate paleontologist at the University of Bristol in England and cochair of the Society of Vertebrate Paleontology meeting.

"These exceptional fossils provide us with evidence that has been missing until now," Xu said. "Now it all fits neatly into place, and we have tied up some of the loose ends."

Images: 1) Zhao Chuang/Xing Lida. 2) Xing Xu et al.

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Friday, 25 September 2009

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

How to Truck 66 200,000-Pound Antennas to 16,000 Feet

Posted: 25 Sep 2009 11:31 AM PDT


After a 17-mile trek up to a plateau in the Chilean Andes, scientists installed the first of 66 giant antennae on the European Southern Observatory's Atacama Large Millimeter/submillimeter Array (ALMA) telescope this week.

The antenna, which weighs about 100 tons and measures 40 feet in diameter, was carried to its operations site at 16,400 feet by a massive, custom-built transporter. Eventually, the antenna will be linked with dozens of others to form a single, enormous telescope. Scientists hope the extremely dry air on the Chajnantor Plateau will help ALMA study some of the coldest and most distant objects in the observable universe.

But because of the harsh conditions on the plateau, each antenna must be built at a base camp at 9,500 feet and then transported up to its concrete pad at the observation site. Once there, the array must be able to survive harsh winds and freezing temperatures, while still maintaining enough precision to point out a golf ball from about 10 miles away.

The first antenna began its journey when one of the two ALMA transporters, affectionately called "Otto," hoisted the enormous white disk onto its back (below).


While the transporter can theoretically travel more than seven miles per hour with an antenna on its back, the vehicle moved extra carefully on its first trek, taking a total of seven hours to travel 17 miles across the Chilean desert.



Once the antenna reached its new home, the transporter used laser-guided steering and ultrasonic collision detectors to guide the disk into its docking station, a concrete pad equipped with power and fiber optic connections.


As more and more antennae are added to the array, the transporter's special sensors will be crucial to keep it from accidentally colliding with an antenna. Even after ALMA is fully operational, ESO scientists say they'll use the custom-built transporters to move antennae between the concrete pads, which will adjust the telescope's view of the sky.



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Sydney’s Apocalyptic Dust Storm Seen From Space

Posted: 25 Sep 2009 08:54 AM PDT


On September 23, Sydney woke up to a surreal scene that looked more like Mars than Australia. The entire city had turned red due to an enormous dust storm. Our readers in Sydney sent us their eerie photos of this event as it was happening. NASA's Terra satellite also captured the incredible event in these images with a spectroradiometer.

Above, the wall of dust blown from inland stretches along the populated coast around Sydney on the morning of September 23. The outline of the continent is faintly traced in the image for reference. Individual point sources for the dust can be discerned. And, according to NASA and the Australian Broadcasting Corporation, some of them were identified as rectangular agricultural plots that have been dried out by several years of drought in Australia. A high-resolution image is available from NASA.

Below, the Terra satellite imaged the dust beneath storm clouds the next morning, September 24, as it blew south across the Tasman Sea toward New Zealand, which is in the bottom right corner of the image. The picture covers 1,450 miles from north to south with a resolution of 155 miles per pixel. At this point, the plume had stretched 2,700 miles, roughly the width of the continental United States. A high-resolution image is available from NASA.


Images: NASA

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Photo: The Sun Gets Its Spots (Back)

Posted: 24 Sep 2009 03:27 PM PDT


Two sunspots are visible on our star's face for the first time in more than a year, possibly ending an unexpected lull in solar activity.

Solar flares rise and fall on an 11-year cycle, so scientists thought sunspot activity would pick up some time in 2008. It didn't. And this year has been quiet, too. No sunspots have been visible on the sun for 80 percent of the days this year.

Sunspot activity is correlated with the total amount of energy we receive from the sun. If the sun's activity were to change remarkably, it would have an influence on global climate. So, in the context of climate change, the fact that the current solar minimum has been the longest and deepest in more than a century has been of special interest.

In May, a big sunspot seemed to augur a return to normal, but it faded away and sunspotless days returned. The latest activity might not mark the end of the solar minimum, however. People have been counting sunspots since Galileo first observed one in the early 17th century. Through the 28 documented cycles, stretching from 1745 to today, some variation in cycle length has been observed.

That's why NASA's former chief sunspot watcher, Michael Kaiser, told us earlier this year that the minimum was "not out of the extreme ordinary."

The photo above is of one of the sunspots, AR 1026. It was sent to by solar photographer, Trevor Little. Little lives in southern England and snaps his gorgeous photos with "a Solarmax 60 telescope and a Lumenera Skynyx 2-0m CCD camera."

If you're an astronomer and you want to share images with Wired Science. Please Tweet us @wiredscience or send an email to our editor, Betsy Mason.

(For you sticklers out there, the polarity of solar storms alternates, so technically, a full solar cycle is 22 years long.)

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Craters Show 1970s Viking Lander Missed Martian Ice by Inches

Posted: 24 Sep 2009 12:38 PM PDT


Meteorites that crashed into the Martian surface last year exposed buried ice to the digital eyes of NASA spacecraft.

Scientists have used those images to deduce that there is a lot more ice on Mars — and that it's closer to the equator — than previously thought. In fact, subterranean Martian ice should extend all the way down beyond 48 degrees of latitude, according to the model, which was published in Science Thursday.

That happens to be where the Viking Lander 2 was in operation from 1976 to 1980. As part of its science program, the Lander dug a trench about 6 inches deep. The new model predicts that if it had gone an extra 3.5 inches — a bit longer than a credit card — it would have hit ice.

It's difficult to project backwards in time what that discovery would have done to the Martian science program, but its impact could have been large.

"To find ice that far from the pole where Viking 2 was, it would have changed the way everyone looked at Mars for the next 20 years," said NASA Goddard archivist, David Williams, who curates the Viking project historical site. "It would have been a whole different model for Mars… If they'd dug down just a little more, they'd have this complete opposite view of Mars."

At the time, scientists didn't really know a lot about the Red Planet. Finding ice underground might not have been that surprising, but largely because the planetologists didn't have a lot of firm theories about water on Mars. They thought there was ice at the poles, Williams said, but not much more than that.

Unlike the Phoenix Lander, the Viking 2 Lander's trenching tool wasn't designed to search for or find ice. Its job was to deliver Martian soil to a series of tests.

As such, Viking 2 wouldn't have been able to do much with any hard ice that it found, said Steven Squyres, an astronomer at Cornell and lead investigator of the Mars Rover missions. Its arm just wasn't powerful enough. Squyers also noted that the Viking missions were a tremendous success, without a water ice find.

But the Viking 2 Lander's work did give the impression that water ice did not exist near the Martian surface in the mid-latitudes. We'll never know how NASA's "Follow the Water" missions to Mars might have changed if, for some reason, the Lander had been commanded to dig just a bit deeper and hit a hard, icy surface.

It goes to show that sometimes scientific discoveries can come down to a few inches and some luck, even on the surface of a planet hundreds of millions miles away.


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Butterflies Use Antenna GPS to Guide Migration

Posted: 24 Sep 2009 11:19 AM PDT


Scientists have finally located the 24-hour clock that guides the migration of monarch butterflies. Instead of being in the brain where most people expected, it turns out the circadian clock is located in the butterflies' antennae.

Every fall, monarchs make an impressive 2,000-mile trek south, using the sun to guide them to the exact same wintering spot in central Mexico. But because the sun is a moving target, changing position throughout the day, biologists have long speculated that in addition to having a "sun compass" in their brains, butterflies must use some kind of 24-hour clock to guide their migration. Now, researchers have located this special GPS system, but it's not what everyone expected.

"The assumption was that we knew where in the brain the molecular clock for this process was," said biologist Steven Reppert of the University of Massachusetts, who co-authored the paper published Thursday in Science. "Almost everyone you would ask prior to this work would say, 'Well, of course the clock has to be in the brain. Where else would it be?'"

Reppert and his team had been studying the ability of butterfly antenna to sense odors when they uncovered something surprising: When they clipped off the insects' antennae and tethered them in a flight simulator, the butterflies no longer flew in a uniform direction.

"It was remarkable, the difference," Reppert said. "The ones without antennae still flew straight, but as a population they were flying in all different directions, compared to the population of migrants with intact antennae that was all going in a southwesterly direction." Without their feelers, the butterflies lost the ability to navigate using the sun, as if they could no longer adjust their direction based on the time of day.

But when the researchers looked for molecular changes in the brains of the antennae-less butterflies, they found that circadian rhythms in the brain were unaffected by clipping the antennae. "This raised the heretical prospect that the timing mechanism may actually be in the antennae," Reppert said.

The researchers tested their hypothesis by painting the antennae of half their butterflies with black enamel, which blocked all input from the sun, and the other half with clear paint that allowed the sun's rays through. While the monarchs covered with clear paint kept flying south, the butterflies with blacked-out antennae started to drift consistently north, suggesting that their molecular clock was running about an hour off schedule.

butterflygps2"The antennal clock is therefore rather like a standalone global positioning system that one might use while driving, which now eclipses the paper map (brain clock)," biologist Charalambos Kyriacou of the University of Leicester wrote in a commentary about the research, also published Thursday in Science. "This result is surprising, given that several studies have set the stage for a brain clock to mediate navigation."

Reppert says the new finding not only changes how scientists think about butterfly antennae, but may also suggest a similar role for an antennal clock in other types of insects, such as bees and ants, that also operate elaborate navigation systems. Like butterflies, honeybees use a sun compass to find flowers and communicate their specific position to the rest of the hive, and they could be using a circadian clock in their antenna to adjust the sun's position to the time of day.

"I think it's a really interesting and elegant paper," said butterfly researcher Karen Oberhauser of the University of Minnesota, who was not involved in the research. But given the incredible sensory powers of insect antennae, she said she's not too surprised that the feelers can also keep time.

"Our sensory systems are really localized to our heads, but insects can taste with their feet and smell with their antennae, and probably their abdomens have pretty complex sensory systems, too," Oberhauser said. "Because insect sensory systems are so different than our sensory systems, it's sometimes difficult for us to even ask the right questions. That's what's so interesting about the work that's being done in the Reppert lab— they're really delving into these detailed questions."

Image 1: Monarch Watch/Chip Taylor. Image 2: M. Twombly, copyright AAAS/Science.

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Brain Scans Reveal What You’ve Seen

Posted: 24 Sep 2009 08:54 AM PDT


Scientists are one step closer to knowing what you've seen by reading your mind.

Having modeled how images are represented in the brain, the researchers translated recorded patterns of neural activity into pictures of what test subjects had seen.

Though practical applications are decades away, the research could someday lead to dream-readers and thought-controlled computers.

"It's what you would actually use if you were going to build a functional brain-reading device," said Jack Gallant, a University of California, Berkeley neuroscientist.

The research, led by Gallant and Berkeley postdoctoral researcher Thomas Naselaris, builds on earlier work in which they used neural patterns to identify pictures from within a limited set of options.

The current approach, described Wednesday in Neuron, uses a more complete view of the brain's visual centers. Its results are closer to reconstruction than identification, which Gallant likened to "the magician's card trick where you pick a card from a deck, and he guesses which card you picked. The magician knows all the cards you could have seen."

In the latest study, "the card could be a photograph of anything in the universe. The magician has to figure it out without ever seeing it," said Gallant.

To construct their model, the researchers used an fMRI machine, which measures blood flow through the brain, to track neural activity in three people as they looked at pictures of everyday settings and objects.

As in the earlier study, they looked at parts of the brain linked to the shape of objects. Unlike before, they looked at regions whose activity correlates with general classifications, such as "buildings" or "small groups of people."

Once the model was calibrated, the test subjects looked at another set of pictures. After interpreting the resulting neural patterns, the researchers' program plucked corresponding pictures from a database of 6 million images.

Frank Tong, a Vanderbilt University neuroscientist who studies how thoughts are manifested in the brain, said the Neuron study wasn't quite A pure, draw-from-scratch reconstruction. But it was impressive nonetheless, especially for the detail it gathered from measurements that are still extremely coarse.

The researchers' fMRI readings bundled the output of millions of neurons into single output blocks. "At the finer level, there is a ton of information. We just don't have a way to tap into that without opening the skull and accessing it directly," said Tong.

Gallant hopes to develop methods of interpreting other types of brain activity measurement, such as optical laser scans or EEG readings.

He mentioned medical communication devices as a possible application, and computer programs for which visual thinking makes sense — CAD-CAM or Photoshop, straight from the brain.

Such applications are decades away, but "you could use algorithms like this to decode other things than vision," said Gallant. "In theory, you could analyze internal speech. You could have someone talk to themselves, and have it come out in a machine."

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Citation: "Bayesian Reconstruction of Natural Images from Human Brain Activity." By Thomas Naselaris, Ryan J. Prenger, Kendrick N. Kay, Michael Oliver, and Jack L. Gallant. Neuron, Vol. 63 Issue 6, September 24, 2009.

Image: From Neuron. Images seen by test subjects are in the left column. In the middle the image reconstructions returned by the researchers' older, structure-focused analysis. At right are the image reconstructions produced by the newer, category-including model.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points.

Water Found on the Moon

Posted: 23 Sep 2009 05:47 PM PDT


Scientists' understanding of the moon could be all wet. Its surface is surprisingly dewy and its interior contains more water than previous analyses of moon rocks have indicated, according to new studies.

sciencenewsObservations from three spacecraft suggest that water is widely distributed over a thin layer of the lunar surface rather than locked up in icy enclaves predicted to lie at the moon's poles. The results, detailed in a trio of papers posted online September 24 in Science, suggest that liquid water may be more available to future moon explorers than had been thought. Concentrations in sunlit soil might average about 1,000 parts per million, the equivalent of roughly a quart of water per ton of material. That water doesn't remain on the moon, but comes and goes each lunar day.

In contrast, water molecules bound to phosphate minerals within volcanic rocks — material that formed well beneath the lunar surface — date back several billion years, says Francis McCubbin of the Carnegie Institution for Science in Washington D.C. A fourth, unpublished study led by McCubbin finds a surprisingly high abundance of this interior water, which may shed new light on how the moon formed.

The researchers who made the surface observations caution that their observations, which are based on low-resolution spectroscopy of minerals on the lunar surface, cannot clearly distinguish between water and the hydroxyl ion, which can serve as a marker for water.

Nonetheless, Roger N. Clark of the U.S. Geological Survey in Flagstaff, Ariz., asserts that "this is the first detection of water on the moon and we see it all over, not just in the polar regions." Clark, a coauthor of two of the Science papers, led a team that found evidence of water in spectra taken by the Cassini spacecraft as it flew past the moon in 1999. Clark says he knew his team had a real signal a while ago, but he says he waited to publish because "the detection was so fantastic, I felt we needed confirmation."

Confirmation has now come in the form of spectra taken by instruments aboard NASA's Deep Impact spacecraft and Chandrayaan-I, India's first mission to the moon. Each of the papers in Science reports data from one of the spacecraft.

Last week, other researchers reported that the Lunar Reconnaissance Orbiter spacecraft had found hydrogen on the moon's surface, a possible marker of water (SN Online: 9/18/09).

The three Science papers "present a strong case for surficial water on the moon, and this could certainly be the result of delivery by icy impactors or solar wind interactions long after the moon formed," comments Robin Canup of the Southwest Research Institute in Boulder, Colorado, who is not a member of any of the teams.

Data collected by Deep Impact one-quarter of a lunar day apart reveal that layers of water only a few molecules thick form, evaporate into space and then reform each lunar day, notes Jessica Sunshine of the University of Maryland in College Park, lead author of the Deep Impact study.

An obvious driver of such a cycle would be hydrogen ions delivered by the solar wind. The ions could interact with oxygen-rich minerals on the lunar surface to produce water, Sunshine suggests. Heat from the sun could then vaporize the water each lunar noon. Although the long-term effects of this interaction on the moon are unknown, "this same process should be occurring on airless, silicate-rich bodies throughout the inner solar system," she says.

In McCubbin's study of the lunar interior, he and his colleagues calculate that phosphate minerals contain a concentration of water as high as several thousand parts per million. This result, combined with lower abundances of water in other volcanic material reported in 2008 by Alberto Saal of Brown University in Providence, Rhode Island points to an average overall abundance of water in the lunar mantle significantly higher than the previous estimate of 1 part per billion.

It's been a long-standing assumption, notes Canup, that if the moon formed when a giant, Mars-sized impactor smacked into the young Earth, any water would have been vaporized by the high temperatures generated during such a cataclysm and that vapor would have escaped into space. However, that assumption "has yet to be evaluated with direct models," she adds.

McCubbin agrees that there may have been some way for water to be retained in this accepted model of the moon's formation. Any alternative explanation of moon formation will have to account for all the water now known to reside inside the moon.

On October 9, a NASA spacecraft called LCROSS will deliberately crash into a cratered area of the moon's south pole, where frozen water likely resides. The resulting plume of kicked-up soil should reveal the abundance of water there.

Says Canup: "Our picture of a bone-dry moon is clearly in need of updating."

Image: Schematic showing the stream of charged hydrogen ions carried from the sun by the solar wind. / University of Maryland, F. Merlin, McREL
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1 Million Spiders Make Golden Silk for Rare Cloth

Posted: 23 Sep 2009 12:39 PM PDT


A rare textile made from the silk of more than a million wild spiders goes on display today at the American Museum of Natural History in New York City.

To produce this unique golden cloth, 70 people spent four years collecting golden orb spiders from telephone poles in Madagascar, while another dozen workers carefully extracted about 80 feet of silk filament from each of the arachnids. The resulting 11-foot by 4-foot textile is the only large piece of cloth made from natural spider silk existing in the world today.

1-spiders"Spider silk is very elastic, and it has a tensile strength that is incredibly strong compared to steel or Kevlar," said textile expert Simon Peers, who co-led the project. "There's scientific research going on all over the world right now trying to replicate the tensile properties of spider silk and apply it to all sorts of areas in medicine and industry, but no one up until now has succeeded in replicating 100 percent of the properties of natural spider silk."

Peers came up with the idea of weaving spider silk after learning about the French missionary Jacob Paul Camboué, who worked with spiders in Madagascar during the 1880s and 1890s. Camboué built a small, hand-driven machine to extract silk from up to 24 spiders at once, without harming them.

"Simon managed to build a replica of this 24-spider-silking machine that was used at the turn of the century," said Nicholas Godley, who co-led the project with Peers. As an experiment, the pair collected an initial batch of about 20 spiders. "When we stuck them in the machine and started turning it, lo and behold, this beautiful gold-colored silk started coming out," Godley said.

Father Comboué, who one historical text erroneously calls Father Comboné, had a partner in designing his machine, M. Nogué. Together, they got quite a spider silk fabric industry going in Madagascar and even exhibited "a complete set of bed hangings" at the Paris Exposition of 1898. That fabric has since been lost, but the exhibition brought them some attention, excerpted below.

"It should be said that the female halabe allows herself to be relieved of her silken store with exemplary docility and this in spite of the fact that she is distinguished for her ferocity; her usual treatment of the males who pay her court is to eat them and she feasts without compunction on members of her own sex weaker than herself. M Nogue's apparatus consists of a sort of stocks arranged to pin down on their backs a dozen spiders. The spiders accept this imprisonment with resignation and lie perfectly quiet while the silken thread issuing from their bodies is rapidly wound on to a reel by means of a cleverly devised machine worked by hand." — Great Britain Board of Trade Journal

"The first experiments of Father Comboné were made in the simplest manner. The spiders were imprisoned in match boxes and by slightly compressing the abdomen he managed to extract and wind upon a little reel turned by hand it thread that sometimes attained a length of 500 yards… it is to the ingenuity of M. Nogue, one of the sub directors, that we owe the apparatus which permits the thread to be wound mechanically and to be twisted and doubled in the quickest and most practical manner. This is done by means of a curious little machine, not easy to describe, in which the spiders are imprisoned by the throat while undergoing the operation. Young Malagasy girls go daily to a park near the school to gather three or four hundred spiders which they carry in osier baskets with wooden covers to be divested of their webs… Generally after having submitted to the reeling operation the spiders are put back in the park for a couple of weeks… [The silk's] color when first spun is a beautiful gold and it requires no carding or preparation of any sort before being woven. Will this be the silk of the future?" — The Literary Digest

But to make a textile of any significant size, the silk experts had to drastically scale up their project. "Fourteen thousand spiders yields about an ounce of silk," Godley said, "and the textile weighs about 2.6 pounds. The numbers are crazy."

Researchers have long been intrigued by the unique properties of spider silk, which is stronger than steel or Kevlar but far more flexible, stretching up to 40 percent of its normal length without breaking. Unfortunately, spider silk is extremely hard to mass produce: Unlike silk worms, which are easy to raise in captivity, spiders have a habit of chomping off each other's heads when housed together.

3-weavingTo get as much silk as they needed, Godley and Peers began hiring dozens of spider handlers to collect wild arachnids and carefully harness them to the silk-extraction machine. "We had to find people who were willing to work with spiders," Godley said, "because they bite."

By the end of the project, Godley and Peers extracted silk from more than 1 million female golden orb spiders, which are abundant throughout Madagascar and known for the rich golden color of their silk. Because the spiders only produce silk during the rainy season, workers collected all the spiders between October and June.

Then an additional 12 people used hand-powered machines to extract the silk and weave it into 96-filament thread. Once the spiders had been milked, they were released into back into the wild, where Godley said it takes them about a week to regenerate their silk. "We can go back and re-silk the same spiders," he said. "It's like the gift that never stops giving."

Of course, spending four years to produce a single textile of spider silk isn't very practical for scientists trying to study the properties of spider silk or companies that want to manufacture the fabric for use as a biomedical scaffold or an alternative to Kevlar armor. Several groups have tried inserting spider genes into bacteria (or even cows and goats) to produce silk, but so far, the attempts have been only moderately successful.

Part of the reason it's so hard to generate spider silk in the lab is that it starts out as a liquid protein that's produced by a special gland in the spider's abdomen. Using their spinnerets, spiders apply a physical force to rearrange the protein's molecular structure and turn it into solid silk.

"When we talk about a spider spinning silk, we're talking about how the spider applies forces to produce a physical transformation from liquid to solid," said spider silk expert Todd Blackledge of the University of Akron, who was not involved in creating the textile. "Scientists simply can't replicate that as well as a spider does it. Every year we're getting closer and closer to being able to mass-produce it, but we're not there yet."

For now, it seems we'll have to be content with one incredibly beautiful cloth, graciously provided by more than a million spiders.

Images: 1) AMNH/R. Mickens 2) Nicholas Godley and Simon Peers

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9 Environmental Boundaries We Don’t Want to Cross

Posted: 23 Sep 2009 11:39 AM PDT


Climate change threatens to turn the planet into a stormy, overheated mess: That much we know. But according to 28 leading scientists, greenhouse gas pollution is but one of nine environmental factors critical to humanity's future. If their boundaries are stretched too far, Earth's environment could be catastrophically altered — and three have already been broken, with several others soon to follow.

This grim diagnosis, published Wednesday in Nature, is the most ambitious assessment of planetary health to date. It's a first-draft users' manual for an era that scientists dub the "anthropocene," in which nearly seven billion resource-hungry humans have come to dominate ecological change on Earth. The scientists' quantifications are open to argument, but not the necessity of their perspective.

"It's a crude attempt to map the environmental space in which we can operate," said Jon Foley, director of the University of Minnesota's Institute on the Environment and one of the paper's lead authors. "We need to keep our activities in a certain range, or the planet could tip into a state we haven't seen in the history of our civilization."

Thresholds for atmospheric carbon dioxide and ozone have already been described, and are widely known to the public. But the scientists say five other factors are just as important: ocean acidification, nitrogen and phosphorus pollution, land use, freshwater use and biodiversity. They say chemical pollution and atmospheric aerosols may also be essential, but can't yet be quantified.

Values for the proposed boundaries are still just estimates, and don't account for how pushing one could affect another — how, for example, acidification that kills plankton could make it harder for the ocean to absorb CO2 and rebound from nitrogen pollution. Ecological models still can't capture the entirety of Earth's biological, geological and chemical processes, and it's impossible to run whole-Earth experiments — except, arguably, for the experiment that's going on now.

Despite those uncertainties, one aspect of Earth's behavior is becoming clear. Records of global transitions between geological ages, and of regional changes between environmental stages, suggest that planet-wide change could happen relatively quickly. It might not take thousands or millions of years for Earth's environment to be altered. It could happen in centuries, perhaps even decades.

Exactly what Earth would look like is difficult to predict in detail, but it could be radically different from the mild environment that has prevailed for the last 10,000 years. It was temperate stability that nurtured the rise of civilization, and it should continue for thousands of years to come, unless humanity keeps pushing the limits.

"The Earth of the last 10,000 years has been more recognizable than the Earth we may have 100 years from now. It won't be Mars, but it won't be the Earth that you and I know," said Foley. "This is the single most defining problem of our time. Will we have the wisdom to be stewards of a world we've come to dominate?"