Hubble Captured Searchlight Beams from a Preplanetary Nebula

Hubble Space Telescope has been at the cutting edge of research into what happens to stars like our sun at the ends of their lives. One stage that stars pass through as they run out of nuclear fuel is called the preplanetary or protoplanetary nebula stage. A new Hubble image of the Egg Nebula shows one of the best views to date of this brief but dramatic phase in a star's life.

The preplanetary nebula phase is a short period in the cycle of stellar evolution, and has nothing to do with planets. Over a few thousand years, the hot remains of the aging star in the center of the nebula heat it up, excite the gas, and make it glow as a subsequent planetary nebula. The short lifespan of preplanetary nebulae means there are relatively few of them in existence at any one time. Moreover, they are very dim, requiring powerful telescopes to be seen. This combination of rarity and faintness means they were only discovered comparatively recently. The Egg Nebula, the first to be discovered, was first spotted less than 40 years ago, and many aspects of this class of object remain shrouded in mystery.

At the center of this image, and hidden in a thick cloud of dust, is the nebula's central star. While we can't see the star directly, four searchlight beams of light coming from it shine out through the nebula. It is thought that ring-shaped holes in the thick cocoon of dust, carved by jets coming from the star, let the beams of light emerge through the otherwise opaque cloud. The precise mechanism by which stellar jets produce these holes is not known for certain, but one possible explanation is that a binary star system, rather than a single star, exists at the center of the nebula.

The onion-like layered structure of the more diffuse cloud surrounding the central cocoon is caused by periodic bursts of material being ejected from the dying star. The bursts typically occur every few hundred years.

The distance to the Egg Nebula is only known very approximately, the best guess placing it at around 3,000 light-years from Earth. This in turn means that astronomers do not have any accurate figures for the size of the nebula (it may be larger and further away, or smaller but nearer).

This image is produced from exposures in visible and infrared light from Hubble's Wide Field Camera 3.

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Becoming Atheists: Analytic Thinking Can Undermine Belief

A series of new experiments shows that analytic thinking can override intuitive assumptions, including those that underlie religious belief.

People who are intuitive thinkers are more likely to be religious, but getting them to think analytically even in subtle ways decreases the strength of their belief, according to a new study in Science.

The research, conducted by University of British Columbia psychologists Will Gervais and Ara Norenzayan, does not take sides in the debate between religion and atheism, but aims instead to illuminate one of the origins of belief and disbelief. "To understand religion in humans," Gervais says, "you need to accommodate for the fact that there are many millions of believers and nonbelievers."

One of their studies correlated measures of religious belief with people's scores on a popular test of analytic thinking. The test poses three deceptively simple math problems. One asks: "If it takes five machines five minutes to make five widgets, how long would it take 100 machines to make 100 widgets?" The first answer that comes to mind—100 minutes—turns out to be wrong. People who take the time to reason out the correct answer (five minutes) are, by definition, more analytical—and these analytical types tend to score lower on the researchers' tests of religious belief.

But the researchers went beyond this interesting link, running four experiments showing that analytic thinking actually causes disbelief. In one experiment, they randomly assigned participants to either the analytic or control condition. They then showed them photos of either Rodin's The Thinker or, in the control condition, of the ancient Greek sculpture Discobolus, which depicts an athlete poised to throw a discus. (The Thinker was used because it is such an iconic image of deep reflection that, in a separate test with different participants, seeing the statue improved how well subjects reasoned through logical syllogisms.) After seeing the images, participants took a test measuring their belief in God on a scale of 0 to 100. Their scores on the test varied widely, with a standard deviation of about 35 in the control group. But it is the difference in the averages that tells the real story: In the control group, the average score for belief in God was 61.55, or somewhat above the scale's midpoint. On the other hand, for the group who had just seen The Thinker, the resulting average was only 41.42. Such a gap is large enough to indicate a mild believer is responding as a mild nonbeliever—all from being visually reminded of the human capacity to think.

Another experiment used a different method to show a similar effect. It exploited the tendency, previously identified by psychologists, of people to override their intuition when faced with the demands of reading a text in a hard-to-read typeface. Gervais and Norenzayan did this by giving two groups a test of participants' belief in supernatural agents like God and angels, varying only the font in which the test was printed. People who took the belief test in the unclear font (a typewriterlike font set in italics) expressed less belief than those who took it in a more common, easy-to-read typeface. "It's such a subtle manipulation," Norenzayan says. "Yet something that seemingly trivial can lead to a change that people consider important in their religious belief system." On a belief scale of 3 to 21, participants in the analytic condition scored an average of almost two points lower than those in the control group.

Analytic thinking undermines belief because, as cognitive psychologists have shown, it can override intuition. And we know from past research that religious beliefs—such as the idea that objects and events don't simply exist but have a purpose—are rooted in intuition. "Analytic processing inhibits these intuitions, which in turn discourages religious belief," Norenzayan explains.

Harvard University psychologist Joshua Greene, who last year published a paper on the same subject with colleagues Amitai Shenhav and David Rand, praises this work for its rigorous methodology. "Any one of their experiments can be reinterpreted, but when you've got [multiple] different kinds of evidence pointing in the same direction, it's very impressive."

The study also gets high marks from University of California, Irvine, evolutionary biologist Francisco Ayala, the only former president of the American Association for the Advancement of Science to have once been ordained as a Catholic priest, and who continues to assert that science and religion are compatible. Ayala calls the studies ingenious, and is surprised only that the effects are not even stronger. "You would expect that the people who challenge the general assumptions of their culture—in this case, their culture's religious beliefs—are obviously the people who are more analytical," he says.

The researchers, for their part, point out that both reason and intuition have their place. "Our intuitions can be phenomenally useful," Gervais says, "and analytic thinking isn't some oracle of the truth."

Greene concurs, while also raising a provocative question implicit in the findings: "Obviously, there are millions of very smart and generally rational people who believe in God," he says. "Obviously, this study doesn't prove the nonexistence of God. But it poses a challenge to believers: If God exists, and if believing in God is perfectly rational, then why does increasing rational thinking tend to decrease belief in God?"

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Secret Binary Code Threatens Science

Missing source code can allow bad science to slip through the cracks and means extra headaches for scientists who want to closely follow up on new studies or check for errors

Modern science relies upon researchers sharing their work so that their peers can check and verify success or failure. But most scientists still don't share one crucial piece of information — the source codes of the computer programs driving much of today's scientific progress.

Such secrecy comes at a time when many researchers write their own source codes — human-readable instructions for how computer programs do their work — to run simulations and analyze experimental results. Now, a group of scientists is arguing for new standards that require newly published studies to make their source codes available. Otherwise, they say, the scientific method of peer review and reproducing experiments to verify results is basically broken.

"Far too many pieces of code critical to the reproduction, peer-review and extension of scientific results never see the light of day," said Andrew Morin, a postdoctoral fellow in the structural biology research and computing lab at Harvard University. "As computing becomes an ever larger and more important part of research in every field of science, access to the source code used to generate scientific results is going to become more and more critical."

Missing source codes mean extra headache for scientists who want to closely follow up on new studies or check for errors. Such unavailability of source codes can also lead to more bad science slipping through the cracks — unreleased and irreproducible codes played a part in a Duke University case that led to study retractions, scientist resignations and canceled clinical drug trials for lung and breast cancer in 2010.

But of the 20 most-cited science journals in 2010, only three require computer source codes to be made available upon publication. Morin and six colleagues from universities across  the U.S. proposed making such policies universal in a policy forum paper that appears in today's (April 12) issue of the Journal Science (Science is one of the three top journals that require the availability of source codes).

Public funding or policy-setting agencies should throw their weight behind the idea of sharing source codes openly, researchers said. They also proposed that research institutions and universities should use open-source software licenses to allow for source-code sharing while protecting the commercial rights to possible innovation spinoffs from research.

"The encouraging thing is that all of the proposals we have made have already been implemented by various journals, funding agencies and research institutions in one form or another — so there is not a lot of innovation required," Morin told InnovationNewsDaily.

Many scientists have learned to write computer code without formal training, and so they may simply not know of the open-source software culture of sharing such codes, Morin and his colleagues said. Others may simply be embarrassed by the "ugly" code they write for their own research.

But even one-off computer code scripts written for a single study should undergo examination and peer review, Morin said. He has often ended up sharing, reusing or adapting code he had originally written with the intention of a single use.

"If I knew there was a publication requirement for my code, I probably would have done things like comment it better, kept better track of it, and generally put a bit more thought and effort into my code — which would have certainly helped me and others later on when I inevitably tried to reuse or share it, even if just with others in my own research group," Morin said.

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Quantum Communication: First Universal Quantum Network Prototype Links 2 Separate Labs

Physicists demonstrate a scalable quantum network that ought to be adaptable for all manner of long-distance quantum communication

Quantum technologies are the way of the future, but will that future ever arrive?

Maybe so. Physicists have cleared a bit more of the path to a plausible quantum future by constructing an elementary network for exchanging and storing quantum information. The network features two all-purpose nodes that can send, receive and store quantum information, linked by a fiber-optic cable that carries it from one node to another on a single photon.

The network is only a prototype, but if it can be refined and scaled up, it could form the basis of communication channels for relaying quantum information. A group from the Max Planck Institute of Quantum Optics (M.P.Q.) in Garching, Germany, described the advance in the April 12 issue of Nature. (Scientific American is part of Nature Publishing Group.)

Quantum bits, or qubits, are at the heart of quantum information technologies. An ordinary, classical bit in everyday electronics can store one of two values: a 0 or a 1. But thanks to the indeterminacy inherent to quantum mechanics, a qubit can be in a so-called superposition, hovering undecided between 0 and 1, which adds a layer of complexity to the information it carries. Quantum computers would boast capabilities beyond the reach of even the most powerful classical supercomputers, and cryptography protocols based on the exchange of qubits would be more secure than traditional encryption methods.

Physicists have used all manner of quantum objects to store qubits—electrons, atomic nuclei, photons and so on. In the new demonstration, the qubit at each node of the network is stored in the internal quantum state of a single rubidium atom trapped in a reflective optical cavity. The atom can then transmit its stored information via an optical fiber by emitting a single photon, whose polarization state carries the mark of its parent atom's quantum state; conversely, the atom can absorb a photon from the fiber and take on the quantum state imprinted on that photon's polarization.

Because each node can perform a variety of functions—sending, receiving or storing quantum information—a network based on atoms in optical cavities could be scaled up simply by connecting more all-purpose nodes. "We try to build a system where the network node is universal," says M.P.Q. physicist Stephan Ritter, one of the study's authors. "It's not only capable of sending or receiving—ideally, it would do all of the things you could imagine." The individual pieces of such a system had been demonstrated—atoms sending quantum information on single emitted photons, say—but now the technologies are sufficiently advanced that they can work as an ensemble. "This has now all come together and enabled us to realize this elementary version of a quantum network," Ritter says.

Physicists proposed using optical cavities for quantum networks 15 years ago, because they marry the best features of atomic qubits and photonic qubits—namely that atoms stay put, making them an ideal storage medium, whereas photons are speedy, making them an ideal message carrier between stationary nodes. But getting the photons and atoms to communicate with one another has been a challenge. "If you want to use single atoms and single photons, as we do, they hardly interact," Ritter adds.

That is where the optical cavity comes in. The mirrors of the cavity reflect a photon past the rubidium atom tens of thousands of times, boosting the chances of an interaction. "During this time, there's enough time to really do this information exchange in a reliable way," Ritter says. "The cavity enhances the coupling between the light field and the atom."

The M.P.Q. group put their prototype network through a series of tests—transferring a qubit from a single photon to a single atom and reversing the process to transfer information from an atom onto a photon. Combining those read/write operations, the physicists managed to transmit a qubit from one rubidium atom to another located in a separate laboratory 21 meters away, using a messenger photon as the carrier between nodes. (The actual length of optical fiber connecting the two nodes is 60 meters, because it snakes along an indirect route.)

A significant number of the photons get lost along the way, limiting the efficiency of the process. But in principle, optical fibers could connect nodes at greater distances. "We're absolutely not limited to these 21 meters," Ritter says. "This 21 meters is just the distance that we happened to have between the two labs."

The researchers also demonstrated that their photonic link can be used to entanglethe two distant atoms. Quantum entanglement is a phenomenon by which two particles share correlated properties—in other words, the quantum state of one particle depends on the state of its entangled partner. Manipulating one of the particles, then, affects the other particle's state, even if it is located in another laboratory. Researchers hope that entanglement can be harnessed to circumvent the photon losses that come from passage through optical fibers. In a proposed application called a quantum repeater, a series of nodes, linked by entanglement, would extend the quantum connection down the line without depending on any one photon as the carrier.

Ritter acknowledges that the new work is simply a prototype, and one for which numerous improvements are possible. For instance, the transfer of a quantum state between labs succeeded only 0.2 percent of the time, owing to various inefficiencies and technical limitations. "Everything is at the edge of what can be done," he says. "All these characteristics are good enough to do what we've done, but there are clear strategies to pursue to make them even better."

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