Friday, 19 November 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Extragalactic Exoplanet Found Hiding Out in Milky Way

Posted: 18 Nov 2010 03:20 PM PST

Some extrasolar planets are truly out of this world.

Astronomers have for the first time discovered a planet in the Milky Way that came from another galaxy. The planet, which has a mass of at least 1.25 Jupiters, orbits an elderly star that was ripped from a small satellite galaxy some 6 to 9 billion years ago.

Johny Setiawan and Rainer Klement of the Max Planck Institute for Astronomy in Heidelberg, Germany, describe the finding online November 18 in Science.

"The coolness factor is definitely that the planet and star came from another galaxy," says Sara Seager of MIT, who was not part of the study. "The planet almost certainly formed during the time the star was in the other galaxy."


In hunting for extrasolar planets, Setiawan and his colleagues homed in on HIP 13044, about 2,000 light-years from Earth, because it's part of a stream of stars called Helmi, believed to have originated in another galaxy. The star's motion could also be monitored for many months each year with a spectrograph at the European Southern Observatory's La Silla site in Chile, looking for telltale wobbles that would indicate the tiny tug of an unseen, orbiting planet.

HIP 13044 and the other stars in the Helmi stream stand out in the solar neighborhood because they have elongated orbits that take them about 42,000 light-years above and below the plane of the Milky Way's disk. Such orbits strongly suggest the stars were part of a group torn from a satellite galaxy and stretched out by gravitational tidal forces into a filament or stream.

The discovery, notes planet hunter Scott Gaudi of Ohio State University in Columbus, "is doubly weird: It is a weird planet around a weird star." The star is unusual because it has the lowest abundance of metals — about 1 percent of the sun's — of any star known to have a planet. (In astronomical parlance, a metal refers to any element heavier than helium.) The vast majority of the roughly 500 extrasolar planets known are found around stars with a much higher metal abundance, and the leading theory of planet formation suggests that stars with high metal contents are those that form giant, Jupiter-like planets.

Also unusual is that HIP 13044 is old enough to have exhausted its supply of hydrogen fuel and passed through the red giant phase of evolution, in which it mushroomed in size. Since then the star contracted to a diameter about seven times that of the sun and is now burning helium at its core. A star in this phase of evolution, known as the red horizontal branch, has never before been found to have a planet.

In part, that's because the enhanced activity of old, evolved stars, including the presence of magnetically driven disturbances known as starspots, makes it more difficult to discern a stellar wobble, says Setiawan. In addition, "there is a high risk that you will not find any planets because they have been engulfed by the star during the [red giant] evolutionary phase," he adds.

In order to survive, HIP 13044's planet, which now resides much closer to the star than Mercury does to the sun, must have originally orbited at a much greater distance, the researchers say. That's the only way it could have escaped being swallowed during the time the star was a red giant. (In several billion years, the sun will also become a puffed-up red giant and is likely to engulf Earth and the other inner planets.)

Other planets that resided closer to HIP 13044 would not have been so lucky. One explanation for the star's relatively rapid rate of rotation is that it has been spun up by the angular momentum of planets it swallowed. Other rapidly rotating, elderly stars that have evolved to the red horizontal branch may have had similar dining habits, researchers have previously noted.

Even though the newfound planet has dodged one bullet, it will soon face another. In a few million years, when the star exhausts all the helium forged at its core, it will undergo a more rapid and larger expansion in which the planet is likely to be destroyed.

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Spacecraft Flies Through Cosmic Snowstorm

Posted: 18 Nov 2010 02:52 PM PST

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New images from the EPOXI mission show that comet Hartley 2 is a cosmic snow globe.

The first science results from the Deep Impact spacecraft's Nov. 4 flyby of the comet, presented in a press conference today, show the comet's drumstick-shaped nucleus is surrounded by chunks of ice ranging from as small a snowflake to as large as a basketball.

"When we saw images come down, even in real-time in the raw data, and realized we had a cloud of snow around the nucleus, we were astounded," said planetary scientist Michael A'Hearn, leader of the EPOXI mission that sent the spacecraft to its icy encounter.

"To me this whole thing looks like a snow globe you've shaken," said planetary scientist Peter Schultz of Brown University.

Explore the comet's surprising snowy landscape in the slides that follow.

Image: NASA/JPL-Caltech/UMD

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Universe’s Quantum Weirdness Limits Its Weirdness

Posted: 18 Nov 2010 12:31 PM PST

The more one probes the universe at smaller and smaller scales, the weirder matter and energy seem to behave.

But this strangeness may limit its own extent in quantum mechanics, the theory describing the behavior of matter at an infinitesimal level, according to a new study by an ex-hacker and a physicist.

"We're interested in this question of why quantum theory is as weird as it is, but not weirder," said physicist Jonathan Oppenheim of the University of Cambridge. "It was an unnatural question for people to have asked even 20 years ago. The reason we're able to get these results is that we're thinking of things in the way a hacker might think of things."

A lot of eerie things happen in the quantum world. According to the Heisenberg uncertainty principle, for instance, it's impossible to know everything about a quantum particle. The more precisely you know an electron's position, the less precisely you know its momentum. Stranger still, the electron doesn't even have properties like position and momentum until an observer measures them. It's as if the particle exists in a plurality of worlds, and only by making a measurement can we force it to choose one.

In another weirdness, two particles can be bound together such that observing one causes changes in the other, even when they're physically far apart. This quantum embrace, called entanglement (or more generally, nonlocality), made Einstein nervous. He famously called the phenomenon "spooky action at a distance."

But there's a limit to how useful nonlocality can be. Two separated people can't send messages faster than the speed of light.

"It's surprising that that happens," said Stephanie Wehner, an ex-hacker and quantum-information theorist at the National University of Singapore. "Quantum mechanics is so much more powerful than the classical world, it should surely go up to the limits. But no, it turns out that there is some other limitation."

As strange as quantum mechanics is, it could be stranger.


"The question is, can quantum mechanics be spookier?" Oppenheim said. "Researchers started asking why quantum theory doesn't have more nonlocality, and if there's another theory that could."

It turns out that the amount of nonlocality you can have — that is, how much you can rely on two entangled particles to coordinate their changes — is limited by the uncertainty principle. Oppenheim and Wehner describe how they came to this conclusion in the Nov. 19 issue of the journal Science.

To see the link between uncertainty and nonlocality, Wehner suggests thinking of a game played by two people, Alice and Bob, who are far apart and not allowed to talk to each other.

On her desk, Alice has two boxes and two coffee cups. A referee flips a coin and tells her to put either an even or odd number of cups into the boxes. She has four choices: one cup in the left box, one in the right box, one cup in each box, or no cups at all. This is equivalent to Alice encoding two bits of information, Wehner says. If a cup in a box represents a 1 and no cup represents a 0, Alice can write 00, 01, 10 or 11.

Then the referee asks Bob to guess if there is a cup in either the left or the right box. If he guesses correctly, Alice and Bob both win. This is the same as Bob trying to retrieve one of the bits that Alice encoded.

In the normal, non-quantum world, the best strategy for this (admittedly really boring) game lets the duo win just 75 percent of the time. If they each have one of a pair of entangled particles, they can do better. Alice can influence the state of Bob's particle by observing her own. Bob can then look at his particle and have some idea of what Alice's looks like, and use that information to make a more educated guess about which box has a cup.

But this strategy only improves the pair's odds of winning to 85 percent. Bob can't always guess perfectly because the uncertainty principle says he can't know both bits of information at the same time, Oppenheim and Wehner explained. The stronger the uncertainty principle is, the harder it will be for Bob to retrieve the bit.

"The reason we can't win this game better than 85 percent is because quantum mechanics respects the uncertainty principle," Oppenheim said.

Given the history of these two concepts, linking uncertainty to nonlocality is a little ironic, he noted. In 1935, Albert Einstein tried to tear down the uncertainty principle using entanglement, and wrote in a famous paper with Boris Podolsky and Nathan Rosen that "no reasonable definition of reality could be expected to permit this."

"When people first discovered nonlocality, they hated it," Oppenheim said. "It was just too weird. People tried to eradicate it and undermine it."

As the century wore on, however, physicists realized that creating a near-psychic link between two particles could be useful in cryptography and enable ultra-fast quantum computers.

"Now we've gotten used to it, and we even like it," Oppenheim said. "Then you start wishing there could be more of it."

Although there aren't any immediate practical applications of this link, the finding does reveal some mysteries about the fundamental nature of physics. The discovery could also inform future theories that go beyond quantum mechanics, such as a unified theory of everything.

"We know that our present theories are not consistent, and that there's some underlying theory," Oppenheim said. Physicists don't know what the uncertainty principle or nonlocality will look like in this new theory, "but we at least know that these two things will be locked together."

Image: Another quantum weirdness: Light can behave like a wave or a particle, depending on how you observe it. Credit: flickr/Ethan Hein

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Feds’ Transgenic-Salmon Review Ignores Big Picture

Posted: 18 Nov 2010 11:03 AM PST

When the Food and Drug Administration announces the fate of the AquAdvantage salmon, the first genetically modified (GM) animal ever considered for commercial consumption, they may have considered only a fraction of their decision's consequences.

So far the FDA has focused on whether or not the salmon are safe to eat or might escape and breed with wild fish. They haven't yet considered how GM salmon could affect, for better or worse, public dietary habits or the fallout of a boom in fish farming.

"The way they're defining safety is overly narrow," said Martin Smith, an environmental policy analyst at Duke University and co-author of a Nov. 18 commentary in the journal Science, of the FDA's approval process.

The modified fish is produced by AquaBounty, a Massachusetts-based company which, for more than a decade, has asked the FDA to approve their proprietary breed: an Atlantic salmon with growth-stimulating genes spliced into its DNA from Chinook salmon and ocean pout.

On a tissue-for-tissue basis, the FDA has deemed AquAdvantage flesh to be little different from farmed or "natural" salmon, though critics argue the agency has relied on possibly skewed data provided by the company itself.

Critics also share concern about AquAdvantage salmon escaping and interbreeding with wild salmon, potentially eradicating a majestic portion of the living world's heritage. The GM fish would, however, be sterile and — at least in the beginning — grown inland, far away from any coastline.

(As far as interbreeding goes, well-regulated GM salmon would seem less threatening than farmed salmon, which are already spreading disease and genetic homogeneity among endangered wild populations.)

But that only covers a portion of the issues raised by GM salmon. Just as the FDA was blamed for being short-sighted in its initial approvals of GM crops, by failing to anticipate the inevitable spread beyond farms of modified genes and proteins, they may again be avoiding the larger and long-term ramifications of a biotechnological innovation.


Smith and his colleagues aren't taking a side. They just want the FDA to do the job right.

"We're arguing that they need to think about what this innovation is doing," Smith said. "This is not just about GM salmon. This is about the next transgenic animal for human consumption, and the next after that."

One unconsidered possibility may actually be of great benefit to the public. Should AquAdvantage salmon prove commercially viable, growing faster on less food than their farmed counterparts, total salmon production could rise dramatically and drive down their price to consumers.

As a result, people might eat more salmon, ostensibly using it to replace less-healthy meats in their diet. Given the apparent benefits of eating omega-3 fatty acid-rich fish, that could be a boon to public health.

"GM salmon could put fresh salmon in reach as a protein source for low-income households susceptible to conditions linked to poor nutrition," Smith's team wrote in Science.

GM salmon farming could, however, become so widespread that demand for feed becomes unsustainable.

Like other high-level predators, salmon subsist on large amounts of protein. It already takes about three pounds of wild fish to produce one pound of farmed salmon, and salmon farming consumes a full 40 percent of global fish oil production.

Many ocean fish populations are already over-fished, with base-of-the-food-web populations of small fish — once thought inexhaustible — collapsing under demand for fish meal. A boom in salmon farming could make the problem worse.

"Nobody can predict the future, but you can look at studies of demand for farmed salmon, and come up with some reasonable scenarios," Smith said. "More importantly, you'd set up a precedent for how to think about these innovations."

The FDA's public comment period ends this month, and a decision on AquaAdvantage salmon could come before the year's end.

Other genetically modified animals in the food industry's pipeline include pigs and cows.

Image: AquaBounty

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Citation: "Genetically Modified Salmon and Full Impact Assessment." By Martin D. Smith, Frank Asche, Atle G. Guttormsen, Jonathan B. Wiener. Science, Vol. 330 No. 6007, November 19, 2010

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Analysis of 2008 Collapse Shows Economy Networked for Failure

Posted: 18 Nov 2010 10:40 AM PST

A new study of the 2008 collapse has joined economics and network theory in a graphic depiction of inevitable failure.

In the preceding years, formerly far-flung sectors of the economy had been pulled together, linked by a newly deregulated financial industry. Thus intertwined, the economy took a form known to network theorists as "intrinsically fragile," in which a local glitch would cascade into system-wide catastrophe.

"The fact that the system became fundamentally fragile is very clear in the data," said systems theorist Yaneer Bar-Yam, president of the New England Complex Systems Institute. "The financial sector was responsible for many of the crucial links in the economy that allowed for shocks to be propagated from one sector to another."

Economists have pointed to financial industry entanglement with the entire U.S. economy as a crucial factor in the 2008 collapse, but Bar-Yam's team drives the point home with new clarity.

In the study, published November 16 on, the researchers used network-mapping tools to analyze the relationships between 500 corporations with the highest stock-trading volume. These were linked to oil prices, bond prices and interest rates.


From this analysis came two striking figures. The first is a map (below) of links between companies in five key economic sectors: technology, oil, other basic materials, finance linked to real estate and other finance. As of 2003, the sectors are relatively distinct, with real estate isolated. By 2008, they're a tightly linked jumble, with finance at the center.

Visualization of market linkage change from 2003 to 2008 in technology (blue), oil (dark grey), other basic materials (light grey), finance including real estate (dark green) and other finance (light green).

The second figure (below) charts how, as the sectors came together, changes in one affected the others. This correlation rises steadily from the millennium's turn until 2008, when the graph reaches its end and its peak.

Other research on network dynamics has shown that interdependence can promote stability, but eventually reaches a point of reversing returns (see "Networked Networks Are Prone to Epic Failure"). Shortly after the peak of interdependence at the end of Bar-Yam's graph came those fateful months when the real estate bubble popped, followed by financial-sector collapse and a hastily averted implosion of the U.S. economy.

Since then, long-standing debates about the role and nature of financial regulation have taken center stage in American politics. Often these degenerate into ideological battles between people who believe market regulation is necessary, and those who think markets should be completely free.

Correlation among stocks from all economic sectors from 1985 to 2008.

Bar-Yam's group doesn't overtly take a side, but they hope their analysis can provide an understanding of the economy's systemic properties and how they've changed.

"We're identifying the actual system. We're not coming in here as ideologues. We're asking, what's going on, and how do we characterize it," he said. "If we don't recognize the vulnerabilities of the system, we will repeat and suffer the consequences."

"Their methodology is a good way of showing what the correlations look like over time," said Federal Reserve Bank of Boston research director Jeffrey Fuhrer. "It gives you a way to look at it that's not biased by a particular ideology. This is what interconnectedness and correlations look like."

Bar-Yam's team traces the financial sector's collapse-inducing economic centrality to the dissolution of Depression-era economic reforms, especially the 1999 repeal of the Glass-Steagall Act. Glass-Steagall had separated deposit banks, where most people keep their savings, and which handled mortgages, from investment banks.

Thus freed and enlarged, the financial sector became the prime source of capital for major parts of the U.S. economy. When the housing market collapsed, the rest followed. Even if housing stayed healthy, it was probably only a matter of time before something else crashed the system, said Bar-Yam.

Under the Dodd-Frank Act, passed in July of this year, the Financial Stability Oversight Council will be responsible for system-oriented market regulations intended to prevent a repeat of the 2008 collapse.

Those regulations have yet to be designed, and what form they might take is unknown. According to applied mathematician Steven Strogatz of Cornell University, inspiration may come from examples of stable networks in biology and even software design.

"I've often wondered why, in biology, cells don't fail when a few reactions go wrong. They don't, because biology has built things in a very modular way. When failures occur, they don't necessarily prove catastrophic," said Strogatz. "In both biology and software design, you don't the parts to be too tightly tied to each other."

Images: 1) Flickr, Rafael Matsunaga. 2) Linkage change from 2003 to 2008 in technology (blue), oil (dark grey), other basic materials (light grey), finance including real estate (dark green) and other finance (light green)./New England Complex Systems Institute. 3) Graph of the amount of correlation among stocks from all economic sectors from 1985 to 2008. The solid black line is the baseline number; shades of grey represent that figure when market-peaking days are removed./New England Complex Systems Institute.

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Citation: "Networks of Economic Market Interdependence and Systemic Risk." By Dion Harmon, Blake Stacey, Yavni Bar-Yam, and Yaneer Bar-Yam. arXiv, November 16, 2010.

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Satellite to Explore Astronaut Poop as Fuel Source

Posted: 18 Nov 2010 08:16 AM PST

By Mark Brown, Wired UK

The United Nations' first satellite, the $5 million UNESCOSat project, has a pretty clear goal: to find out if astronauts' faeces can be used as an effective fuel source in space.

The orbiting craft will launch in 2011 with the aim of assisting in education, promoting public awareness of science, and improving international co-operation. Teachers and students will be able to communicate with the satellite in specially designed space technology courses.

But the craft will also carry a number of student-designed experiments. Schools and academies presented proposals for student research that could be carried out on the satellite, and the space systems program at Florida Institute of Technology was granted two spots. Their payloads will have testing areas, mixing vessels and solenoid pumps, and will be filled to the brim with anaerobic bacteria — the kind that don't require oxygen for growth.


The bacteria in question — Shewanella MR-1 — can break down human faeces into hydrogen, which could top up fuel cells and replenish a spaceship's power source. But the students at Florida want to find out how well the bacteria works when orbiting the planet, and how the bacteria's life cycle will alter when subjected to the different temperatures, pressures and gravities of space.

If the plan proves successful, it could hold very real implications for space travel. As missions move further and further away from Earth, ships need better ways of conserving or generating extra fuel. Scientists have already found a use for waste urine, which is recycled as drinking water on the ISS. Now they've got to figure out a good use for the other stuff.

Image: A space toilet. Flickr/cerebusfangirl


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Blankets of Snot Protect Sleeping Reef Fish From Parasites

Posted: 18 Nov 2010 07:49 AM PST

If you were to find yourself in the jungle without a mosquito net, slathering yourself in snot might be a good alternative. It works for fish: Scientists have discovered that some coral reef fish protect themselves from biting isopods, a marine equivalent of mosquitoes, by covering themselves in mucus before going to sleep at night.

Researchers had speculated that the reason certain parrot fish and wrasses envelop themselves each night with a big blob of mucus might be to protect against settling silt or to deter hungry predators such as moray eels. But definitive experiments were lacking. Now scientists from the University of Queensland in Australia have done the dirty work. The team placed parrot fish in plastic tubs and after midnight, when all the fish had made their mucus cocoons, the researchers gently scraped off the cocoons from half the fishes. Then the team introduced tiny parasitic isopods — blood-sucking crustaceans that are taxonomically closer to lice than to mosquitoes — into the tubs.

Tallying each fish's blood-engorged parasites showed that the mucus acts as a slimy sea version of bug netting: 94 percent of fish without cocoons had bites, versus 10 percent of fish with intact cocoons. The cocoon-challenged fish also had far more bites on average than their counterparts, the researchers report in a paper to appear in Biology Letters.

Making the mucus cocoon, which begins at the fish's mouth and envelops the entire body within an hour, is an efficient protection strategy, costing a mere 2.5 percent of the fishes' daily energy budget, the researchers estimate. This is relatively cheap, compared with scraping yourself on rocks or sand, avoiding areas with parasites or seeking parasite-eating cleaner fish (which the fish do during waking hours).


Keeping bugs at bay is a new role for fish mucus — the thinner slime layer employed by some species appears to protect against UV rays and pollutants, or can aiding in maintaining the proper balance of electrolytes and fluids.

Images: 1) Each night the parrot fish Chlorurus sordidus envelops itself in a cocoon of mucus, a slimy nightgown that protects it from biting parasites. Alexandra Grutter 2) The mucus cocoons made by some reef-dwelling fish protect the sleeping animals from being bitten by the louse-like parasite Gnathia aureusmaculosa (a marine isopod). Nico Smit

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570-Megapixel Camera Prepares to Hunt for Dark Energy

Posted: 18 Nov 2010 04:00 AM PST

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The world's largest dark energy–hunting device, also one of the biggest, heaviest and highest-resolution cameras in the world, is close to completion.

Construction of the 4-ton Dark Energy Camera is wrapping up next month at Fermilab in Illinois, where it's being tested on a mock-up telescope mount (above). The Dark Energy Survey hopes to open its $35 million camera for business at its final destination, in the Blanco telescope atop a Chilean mountain, by October 2011.

There, it will scan deep space for signs of dark energy, an invisible force that's pulling groups of galaxies — and perhaps space itself — apart at faster and faster speeds.

"We're going to survey 300 million galaxies in the southern sky to measure the speed of those galaxies," said Tom Diehl, a physicist at Fermilab and a camera-construction leader. "We want to make the best description of the universe's expansion to date."

The faster an object moves away from the Earth, the more its light shifts toward a red color. Measurements of distant galaxies show all of them are red-shifted and moving away from us and each other.

"What's more, they're moving away faster and faster, like pennies on the surface of an inflating balloon," said Josh Frieman, an astrophysicist who is directing the Dark Energy Survey effort.

Since the 1990s, astronomers suspected this expansion of space is accelerating because of a strange form of energy, dubbed dark energy because of its baffling nature. The new survey should improve our understanding of dark energy by about four to five times through improved red-shift measurements, Diehl said, helping get to the bottom of the mystery.

"We don't know why the universe is speeding up, and that's precisely why we're doing the Dark Energy Survey," Frieman said. "We're trying to pin down the nature of dark energy."

Since 2008, roughly 120 astronomers, engineers, and physicists have worked on the camera. As its construction comes to a close, we take a look at the Dark Energy Camera's progress.


Video: Building the Test Mount

Time-lapse footage of the Dark Energy Camera's test mount being built from January to October 2010. Fermilab

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Via: symmetry breaking

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