Wednesday, 13 October 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Exoplanet Wars: “First Habitable World” May Not Exist

Posted: 12 Oct 2010 02:43 PM PDT

The first exoplanet discovered in the habitable zone could be a mirage, according to reports from an exoplanet meeting yesterday. A second team of astronomers couldn't find the planet in their data.

The long-sought planet, dubbed Gliese 581g, was detected using a combination of 122 observations over 11 years from the Keck Telescope in Hawaii, and 119 published measurements from the HARPS spectrograph that spanned 4.3 years, up until 2008. The HARPS team had already found four other planets circling Gliese 581 by teasing out the star's subtle motion in response to the planets' gravitational tugs.

On Sept. 29, Steven Vogt of the University of California, Santa Cruz and R. Paul Butler of the Carnegie Institution of Washington announced that adding their decade of observations to the data pool pointed to the existence of two more planets. One of the new planets sits squarely in the star's habitable zone, where liquid water could persist at the planet's surface and life could find a foothold.

But not so fast, says the HARPS team. Astronomer Francesco Pepe of the Geneva Observatory in Switzerland, who spoke Oct. 11 at an International Astronomical Union symposium on planetary systems, reported a new analysis using only HARPS data, but adding an extra 60 data points to the observations published in 2008. He and his colleagues could find no trace of the planet.

"I am not overly surprised by this as these are very weak signals, and adding 60 points onto 119 does not necessarily translate to big gains in sensitivity," Vogt told in an e-mail. He added that the non-detection doesn't mean the planet doesn't exist — it may be that it's only detectable using both data sets.

"I do not wish to comment on Pepe's result as I haven't seen his data," Vogt said. "But I have tremendous respect for their work, and look forward to seeing their additional data on this and other systems of mutual interest."

Image: Zina Deretsky/National Science Foundation

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Citizen Science: Trawl World War I Navy Records for Weather Data

Posted: 12 Oct 2010 01:43 PM PDT

A new crowdsourced science project called Old Weather lets you look through handwritten ship captains' logs from the early 20th century and help build better climate models at the same time.

The project was launched Oct. 12 by the Zooniverse, the citizen-science powerhouse behind Galaxy Zoo and Moon Zoo. Until now, most Zooniverse projects have relied on using human eyes to pick out shapes and recognize features of astronomical objects, something computers are notoriously terrible at.

Old Weather puts those sharp recognition skills to work on handwriting. The writing in these logs ranges from scribe-quality copperplate to slapdash and scruffy, and computers make too many errors to be useful for transcribing them. But human eyes and brains are good at interpreting written words, especially as the reader starts to recognize the style of writing and the words the ship captains used.

The data collected from the logbooks will be used by scientists, geographers, historians and the public. Climate scientists can feed hundreds of individual observations of the weather, temperature and air pressure into atmosphere models to build weather maps of the entire globe. Data on the ocean, which is a good store of heat, can provide information on what was happening on land as well.

"We need to collect as much historical data as we can over the oceans," said Clive Wilkinson, coordinator of the Global Coral Reef Monitoring Network, in a how-to video on Old Weather. "If we wish to understand what the weather will do in the future, then we need to understand what the weather was doing in the past."

Image: Old Weather/Zooniverse

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Giant Pterosaurs Could Fly 10,000 Miles Nonstop

Posted: 12 Oct 2010 11:34 AM PDT

PITTSBURGH — Predating jet travel by at least 65 million years wasn't a problem for the biggest pterosaurs. These prehistoric creatures might have been able to fly up to 10,000 miles nonstop, according to research presented Oct. 10 at the annual meeting of the Society for Vertebrate Paleontology.

sciencenewsThe original elite flyers included four species of what biomechanist Michael Habib, of Chatham University in Pittsburgh, calls supergiant pterosaurs: flying reptiles such as Quetzalcoatlus northropi from Texas. Appearing in the fossil record 70 million years ago, they stood about as tall as a modern giraffe and launched into the air spreading membrane wings to a total span of roughly 10 meters [33 feet].

These supergiants "are big by pterosaur standards," Habib said. "They are truly gruesomely huge by bird and bat standards."

If current estimates for pterosaur body masses and wing dimensions are realistic, and if the pterosaurs could catch thermals and glide the way a bird can, "it would make them the longest single-trip-distance fliers in the Earth's history," Habib said. Birds have logged impressive distances considering their small size, such as Arctic terns that basically migrate pole to pole, but birds don't do so in one go.

The new pterosaur calculations raise the possibility that the supergiant fossils found on separate continents can't automatically be considered different species, Habib suggested. "A pterosaur from Big Bend could be mating with a pterosaur from Transylvania," he said.

Huge distances for nonstop travel may sound extreme, said David Unwin, a pterosaur researcher at the University of Leicester in England, but "we didn't fall on the floor laughing" hearing of the idea. Unwin said he welcomes the new figures for at last providing some specifics for discussion.

As for merging any currently misunderstood species, though, he's less sanguine. The pterosaur fossil record is patchy, and big age gaps between specimens suggest that they must be different species, he said.

Also controversial are the basics, such as body mass, that Habib put into his new distance calculations. Habib said he picked estimates yielded by quantitative approaches taken by other researchers. If a pterosaur weighed 200 kilograms [440 pounds] "empty," plus another 72 kilograms [159 pounds] of fat to fuel a long trip, Habib calculated that the animal could soar 10,000 miles nonstop.

For that calculation, Habib tuned his calculations for wings shaped roughly like modern eagles'. Their wings, he said, represent a compromise between a long narrow shape for gliding and a wide wing for heavy lifting.

And yes, Habib said, pterosaurs that heavy really could haul their substantial rumps into the air. Warm Cretaceous temperatures might have given them more thermals to ride, but to be conservative he made them fly in a modern atmosphere. He assumed that pterosaurs could mostly soar between brief bursts of flapping, and he borrowed analytic methods from bird studies to estimate how far fat supplies would take them. Habib got long distances when assuming a metabolic rate about 85 percent that of modern birds.

Even if the different assumptions about weight or wing shape shrink or extend the distance calculations, the bottom line remains the same, Habib said. "What's important is that the numbers are all big."

Image: PLoS One

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Bonobo Females Handier With Tools Than Males

Posted: 12 Oct 2010 11:24 AM PDT

A new study of tool use in bonobos suggests females of this great ape species are handier than males.

That's also been seen in chimpanzees, but it was thought that chimps could be an aberration. Instead, the new study hints suggests that female-driven technological innovation could be the norm in humanity's closest cousins.

"We think that there is this difference in the Pan genus: Females are better tool users than males," said primatologist Thibaud Gruber of Scotland's University of St. Andrews.

The findings, published Oct. 8 in Animal Behavior, started with field work by Gruber and fellow St. Andrews primatologist Klaus Zuberbühler. They saw that wild bonobos used tools as readily as chimpanzees — a surprising finding, said Gruber, as bonobos are generally considered to be socially rather than technologically sophisticated.

The researchers followed their observations with a study of 20 captive bonobos at the Lola ya Bonobo sanctuary in the Democratic Republic of Congo. Once again, they found extensive tool use. But that wasn't all. "We found out that bonobo females were much more keen on using different tools for the same task than males," said Gruber.

In chimpanzees, it's been proposed that the tendency of females to find new ways of cracking nuts or fishing for termites comes from the extra time that young females spend with their mothers. But most of the bonobos at Lola are orphans, said Gruber, suggesting an inborn rather than acquired propensity.

"Their mothers were killed before they could be taught anything. They're arriving very young, at two or three months of age," he said. "The caretakers are showing them all the same things. Over time it seems that females are just picking up way more than the boys."

Gruber speculates that female chimpanzees and bonobos might be adapted to tool use because "they're usually smaller and less strong than males. They also need to cope with pregnancy. They have to develop other techniques to acquire as much food."

It's an open question whether these gender-based proclivities have an analogue in humans, said Gruber. It's easy to think of chimps and bonobos as snapshots of earlier phases in human evolution, but they've also evolved in the 3.7 million years since sharing a common ancestor with Homo sapiens.

That said, the tendency toward female tool use could certainly have emerged before the split. Perhaps "it's not so much the idea of men the hunters that should prevail," said Gruber. "It's females the foragers."

Image: Flickr, Jeroen Kransen

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Citation: "A comparison of bonobo and chimpanzee tool use: Evidence for a female bias in the Pan lineage." By Thibaud Gruber, Zanna Clay and Klaus Zuberbühler. Animal Behavior, in press.

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World’s Most Powerful Laser on Target for Awesome Science

Posted: 12 Oct 2010 10:11 AM PDT

National Ignition Facility target chamber

Scientists recently pulled together the pieces of the world's most powerful laser and, in a first-ever complete dry run, pulled the trigger on a peppercorn-sized pellet of nuclear fuel. The energy crushed the capsule instantly, causing it to spew a shower of neutrons. In short: It worked.

The firing of the National Ignition Facility, or NIF, at Lawrence Livermore National Laboratory, located 40 or so miles east of San Francisco, wasn't an earnest attempt at a more-energy-out-than-you-put-in "ignition" of fusion, the same process that merges atoms at the sun's core — and the facility's ultimate goal. Yet the staff and independent researchers working with the $3.5 billion machine have reason to be optimistic about achieving fusion within two years, even if much of the device's time is earmarked for defense research and prospects of near-limitless and pollution-free energy aren't certain.

"In my mind, to have accomplished this shot is an almost unfathomable scientific achievement," Paul Drake, a physicist at the University of Michigan using NIF as a proving ground for studying supernova physics in the laboratory, told "I've had a lifetime of experience of big science facilities, and find myself in awe of [the NIF team] having made this thing work this fast."

National Ignition Facility laser bayThe research facility's construction began in 1997 and spreads over an area nearly the size of three pro league football fields, most of the space occupied by equipment that revs up 192 laser beams. During the Sept. 29, 2010 firing of the laser, scientists and engineers funneled these beams into a 30-foot-diameter metal sphere at the end of the complex. At the center of this chamber, a tiny plastic pellet filled with heavier forms of hydrogen received a punishing 1 megajoule zap, similar to the instantaneous oomph of a car traveling 100 mph.

According to engineering physicist Edward Moses, who heads up the NIF team, the laser burst was about 75 percent of its full energy capacity. In addition, the cryogenically cooled pellet was filled with deliberately less-than-perfect fuel.

"The last thing we'd ever think about doing is playing cowboy with this thing," Moses said. Throughout the next year or two leading up to an all-or-nothing firing, the facility will make similar integrated shots about once a month.

Richard Petrasso, a fusion scientist at MIT who works with the machine's diagnostic equipment, said the tiptoeing is for a good reason.

"The facility is like a new car engine," Petrasso said. "You don't hit the pedal all the way down to the ground the first time. You have to tune it to get all of the conditions just right — the laser, the diagnostics and the surface of the capsule."

About 10 trillion neutrons zoomed out of the capsule during the test shot, signaling the successful fusion of some tritium and deuterium atoms — the "heavy" hydrogen fuels in the pellet. Moses said 1,000 times more neutrons should fly out during the ultimate goal of a fusion chain reaction.

At that point, if the machine can actually do it, Drake said the scientific payoffs will be huge.

"We're still proving we can do experiments we want, and also for the broader scientific community," Drake said. "But without hesitation, I'd say NIF is on track for doing some pretty awesome science," including simulating Jupiter's oddly magnetic core, the innards of stars and other hot-and-dense environments around the universe.

National Ignition Facility hohlraum fuel pelletAt the end of the day, however, most of NIF's operating time isn't slated for doing fundamental science. Moses said about 10 percent of the machine's time is dedicated to that now and will go up to 20 percent after 2013. Another 40 percent (by 2013) is hedged for more ignition research, and the remaining 40 percent chunk will be for gathering data about fusion physics for the government. In other words, it will simulate fusion bomb explosions without detonating them.

"Strategic security is also part of the mission," Moses said. "We want to make sure we can build virtual test sites on computers, but we need good data to ground the models." If NIF achieves fusion burn, he said it will be the only facility of its kind to safely create the conditions of active weapons.

Beyond NIF's three-pronged mission, there's also the promise of developing a safe fusion energy source that releases 30-40 times the energy put in. The only theorized "pollution" would be helium, which is the universe's most pervasive and inert gas.

"The energy potential is there, for sure," Petrasso said. "The question is about practical implementation. There are a lot of … issues that have to be dealt with to turn it into a reactor that makes energy."

Images: Lawrence Livermore National Laboratory. 1) Inside the National Ignition Facility's 10-meter-diameter target chamber. 2) NIF's laser bay. 2) The container of the tritium/deuterium fuel pellet, called a "hohlraum." Video:

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Birthplace of Modern Astronomy Faces Uncertain Future

Posted: 12 Oct 2010 04:00 AM PDT

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WILLIAMS BAY, Wisconsin— Albert Einstein once said that he'd rather visit the Yerkes Observatory than Niagara Falls. And visiting this historic place, you can understand why.

Back in its heyday, this 113-year-old palace of space science housed one of the best astronomical libraries in the country, the world's largest refracting telescope, and all the astronomy faculty and grad students from the University of Chicago.

But these days, most astronomers would rather be in Chicago. In recent years, the university has reclaimed most of the books, the telescope's research time has been replaced with school tours, and the scientists have trickled 100 miles south to the main campus. Only a handful of researchers remain, and many don't stay year-round.

"When I first came here, new faculty had a choice of where to go, Chicago or up here," said observatory director Kyle Cudworth, who has worked at Yerkes since 1974. "But by 10 years later, they were not given a choice. They were strongly encouraged to go to campus."

Despite the exodus, Yerkes is still an active center of research and engineering. Cudworth and his former student Rick Rees (now a professor at Westfield State University in Massachusetts) use a century's worth of observations from the big telescope to track motions of stars in clusters, work that can be done only at Yerkes. And engineers working in the observatory's ancient cellars are constructing new instruments to fly on airborne telescopes. recently took a tour of this majestic, history-rich observatory to learn why it claims the title "the birthplace of modern astronomy," and what will happen to it now.

Image: Lisa Grossman/

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