Category Archives: Science

Japanese Spacecraft Deploys First-Ever Solar Sail

Written by XARIUSOUND. Posted on June 10, 2010. Filed under Science, Technology. Tagged , , . No comments.

NewImage.jpgThe unfurling of a Japanese solar sail, the first demonstration of a new space propulsion technology, went exactly according to plan.

According toJAXA’s blog posts and photos from the event, the IKAROS spacecraft’s sail appears to be in place. It’s a big step in its attempt to travel driven only by sunlight.

“This is the first sail ever deployed in space, and if they succeed in using it for solar-sail flight — it’ll still be a few weeks before we know that — it’ll be a milestone,” said Louis Friedman, executive director of the Planetary Society, an organization dedicated to promoting space exploration, which is readying its own solar-sailing mission.

A solar sail uses the pressure from photons striking its surface to push the spacecraft through space. Materially, the 650 square-foot sail is made of incredibly thin, aluminized plastic that’s only 0.0003 inches thick, a little thicker than spider silk, or about the diameter of a red blood cell. When a photon strikes its surface, it bounces off, imparting its momentum to the sail. Each photon might not deliver much thrust, but over time, all that light adds up.

“The actual force might be just a few millionths of a g, but because it acts continuously, it allows you to build up large velocity changes over time,” Friedman said. “That’s where a sail really does its work is long missions.”

The Japanese sail also has thin-film solar cells built into it. They could be used to generate electricity to drive an engine that would work alongside the sail.

The key difficulty with such a thin and large object is that it’s hard to deploy. “The things we’re watching for are all their dynamical behaviors that you ultimately can’t model and that might cause undue stress on the material,” Friedman said.

In the IKAROS design, the sail was unfurled by using centrifugal force generated by spinning the craft.

Space-travel proponents are particularly interested in the technology because it doesn’t require fuel, which makes it the leading (and basically) only candidate for very long-distance travel.

“It’s the only way we know — that anybody knows — to ultimately do practical interstellar flight because you don’t have to carry your propellant along with you,” Friedman said. “Anything else you do, whether it’s nuclear or advanced engines, you’re always carrying propellant and the mass becomes too great.”

Gigantic Baby Stars Discovered in Cloud of Space Dust

Written by XARIUSOUND. Posted on April 17, 2010. Filed under Science. Tagged , , , , . No comments.

The previously undiscovered protostars are the small points of orangey light in the center of the image. They are up to 10 times more massive than the sun.

The Herschel Space Observatory, operated by the European Space Agency, obtained the new image, which is a composite of three different wavelengths of light all in the infrared part of the spectrum. Infrared light waves are longer and scatter less than visible light, allowing scientists to probe dust-shrouded areas of space. In this image, the shortest wavelength is blue, the medium green, and the longest red.

The intense star-forming region of the Milky Way is about 5,000 light-years away in the direction of the constellation Monoceros, the Unicorn. This image shows only part of the massive cloud of dust. If the whole thing, seen below, were visible to the naked eye, it would be large in the sky, appearing around five times the size of a full moon.

Early Galaxies

Written by XARIUSOUND. Posted on February 11, 2010. Filed under Science. Tagged , , , . No comments.


The mystery of why galaxies formed early in the history of the universe give birth to more stars than modern ones has been solved. An abundance of dense, cold gas fueled rapid star formation in these early galaxies, according to a new study.

Astronomers collected signals from 19 different 8- to 10-billion-year old galaxies scattered across the northern sky. These early-universe stellar nurseries had much more interstellar gas — dense, hydrogen-rich clouds at a chilly minus 441 to minus 414 degrees Fahrenheit — than their modern counterparts.

“This is really pioneering work,”  said astrophysicist Kai Noeske of the Harvard Smithsonian Center for Astrophysics. ”It unambiguously confirms that these galaxies really are more gas-rich, so the reason they made more stars back in the day is that they had more fuel to burn.”

Scientists study distant galaxies because the light they sent out billions of years ago is only now reaching us, and can therefore tell us about conditions early in the universe’s 13.7-billion-year history.

No one knew why stars form more than 10 to 100 times more often in distant, massive galaxies than they do in local galaxies of the same mass, said astronomer Linda Tacconi of the Max Planck Institute for Extraterrestrial Physics in Germany, lead author of the Feb. 10 Nature study.

Some scientists had guessed that these early galaxies contained more cold interstellar gas, which fueled the frenetic birth of stars.  Others argued that these ancient galaxies had the same amount of gas as the Milky Way, but that suns formed in short, furious starbursts as these galaxies collided, Noeske said.

Determining which theory was right was difficult. The cold, dense gas clouds emit such faint, low-energy light that even the most sensitive instruments can barely detect them. Just a few years ago, Tacconi’s team searched for signals from these galaxies, but failed, she said.

The group was finally able to answer the question by adding more-sensitive detectors to the IRAM Plateau de Bure Interferometer, an array of millimeter-wavelength radio telescopes located at 7,381 feet in the French Alps.

Ultimately, the team wanted to know how much hydrogen filled these early galaxies, because it is by far the most abundant element in the universe and in interstellar gas clouds. But hydrogen emissions from these distant objects are simply too hard to detect, Tacconi said.

Instead, they measured the light emitted from carbon monoxide molecules. As these molecules rotate, they shift from one energy state to another. As they shift, “they emit photons, and that radiation is what we see as an emission line at a specific wavelength,” Tacconi said.

The amount of light emitted from these spinning molecules revealed the fraction of each galaxy made up of carbon monoxide. Carbon monoxide and hydrogen are found in almost the same ratio in many parts of the universe. So, they used this ratio to extrapolate the amount of hydrogen present in these early galaxies.

A 10-billion-year-old galaxy was made of about 44 percent cold interstellar gas by mass, while an 8-billion-year-old one was about 34 percent. This is three to 10 times more hydrogen than today’s giant galaxies.

The study also showed the old galaxies drew in fuel from their surrounding environment in order to keep up the frantic pace of star formation, Noeske said.

Future research should look at a larger number of galaxies and find a way to measure smaller galaxies, said astronomer Dawn Erb of the University of California, Santa Barbara, who was not involved in the study.

“This is just the tail end of the population of the normal galaxies, just the biggest and most massive ones,” she said. “We just can’t see the normal ones, because they’re too faint.”

To do that, the team will need even-more-sensitive equipment, which they will get when the ALMA observatory in Chile comes online in 2012. “That’s going to be the next big step,” Erb said.

Awakening Sun

Written by XARIUSOUND. Posted on February 9, 2010. Filed under Research, Science. Tagged , , , , , , , , . No comments.

As the sun emerges from a long lull in activity, the star’s emissions in the radio band of the spectrum have also picked up. And from a shed on three acres of land outside Santa Fe, New Mexico, amateur radio astronomer Thomas Ashcraft is making recordings of them available for download.

“The Sun has become hyper-dynamic the past few days,” Ashcraft wrote on his website Sunday, along with links to four “specimens” of radio bursts, as he calls them.

The sun is crackling with solar flares now as a very large sunspot continues to circle our star. The recent solar activity almost assuredly signals the end of the solar minimum. Only 5 percent of the days in 2010 have seen a blank sun. In 2008 and 2009, more than 70 percent of the days had no sunspot activity.

Not all bursts sound the same, though. Another kind, Type V, is generally shorter and sharper. They happen to be Ashcraft’s favorites.

“I like that one because they are very strong and very fast,” Ashcraft told Wired.com. “They are only short lived, only a minute or two minutes. You can get a rush out of it. You can get high off of it. You can trip on it a little bit.”

The physics of solar radio emissions are quite complicated, but Ashcraft just likes to listen to the radio static out in the shed on his property. It gives him a feel for what the sun is doing, he said. He held up the phone to his speakers where the standard hiss of the radio, speckled by cosmic background radiation, constantly plays.

“I have that playing at a low level. I’m able to hear when there are sudden fluctuations,” Ashcraft said. “That makes me hypersensitive to the sun. I consider my antennas, which are mostly dipole antennas, I consider them my hyperextended nervous systems, so I can feel subtle solar movements.”

When he processes the recordings, Ashcraft likes to track one frequency (say, 21 megahertz) in one channel and another (say, 24 megahertz) in the other channel. It tends to give his specimens what he calls “spatiality” and a kind of pulsating effect. That’s because he isn’t just trying to record the sun, he’s trying to make it into something with which people can connect.

“I sort of see it as a possible musical form of the future. You know? An energetic form,” Ashcraft said. “Maybe the word isn’t even art anymore, it’s almost nutritional to the nervous system in a way that I don’t know about, but I’m groping towards, kind of as an artist.”

After almost 20 years of studying the sun, Ashcraft said his view of being a human has actually changed.

“I’m very conscious of myself as an organism, an electroreceptor sensing the sun,” Ashcroft said. “It’s human, but the human is a subset of being an organism.”

Almost no energy is lost in between.

Written by XARIUSOUND. Posted on February 4, 2010. Filed under Research, Science. Tagged , , , , , , , . No comments.

By hitting single molecules with quadrillionth-of-a-second laser pulses, scientists have revealed the quantum physics underlying photosynthesis, the process used by plants and bacteria to capture light’s energy at efficiencies unapproached by human engineers.

The quantum wizardry appears to occur in each of a photosynthetic cell’s millions of antenna proteins. These route energy from electrons spinning in photon-sensitive molecules to nearby reaction-center proteins, which convert it to cell-driving charges.

Almost no energy is lost in between. That’s because it exists in multiple places at once, and always finds the shortest path.

“The analogy I like is if you have three ways of driving home through rush hour traffic. On any given day, you take only one. You don’t know if the other routes would be quicker or slower. But in quantum mechanics, you can take all three of these routes simultaneously. You don’t specify where you are until you arrive, so you always choose the quickest route,” said Greg Scholes, a University of Toronto biophysicist.

Scholes’ findings, published Wednesday in Nature, are the strongest evidence yet for coherence — the technical name for multiple-state existence — in photosynthesis.

Two years ago, researchers led by then-University of California at Berkeley chemist Greg Engel found coherence in the antenna proteins of green sulfur bacteria. But their observations were made at temperatures below minus 300 degrees Fahrenheit, useful for slowing ultrafast quantum activities but leaving open the question of whether coherence operates in everyday conditions.

The Nature findings, made at room temperature in common marine algae, show that it does. Moreover, similar results from an experiment on another, simpler light-harvesting structure, announced by Engels’ group last Thursday on the pre-publication online arXiv, suggest that photosynthetic coherence is routine.

The findings are wondrous in themselves, adding a new dimension to something taught — incompletely, it now seems — to every high school biology student. They also have important implications for designers of solar cells and computers, who could benefit from quantum physics conducted in nonfrigid conditions.

“There’s every reason to believe this is a general phenomenon,” said Engel, now at the University of Chicago. He called Scholes’ finding “an extraordinary result” that “shows us a new way to use quantum effects at high temperatures.”

Scholes’ team experimented on an antenna protein called PC645, already imaged at the atomic scale in earlier studies. That precise characterization allowed them to target molecules with laser pulses lasting for one-quadrillionth of a second, or just long enough to set single electrons spinning.

By analyzing changes to a laser beam sent through the protein immediately afterwards, the researchers were able to extrapolate what was happening inside — an ultra-high-tech version of shadows on a screen. They found that energy patterns in distant molecules fluctuated in ways that betrayed a connection to each other, something only possible through quantum coherence.

“It’s the same as when you hit two tuning forks at the same time, and hear a low-pitched oscillation in the background. That’s the interference of sound waves from the forks. That’s exactly what we see,” said Scholes.

According to Scholes, the physics of photosynthetic proteins will be further studied and used to improve solar cell design. Engels suggested their use in long-promised but still-unworkable quantum computing. “This allows us to think about photosynthesis as non-unitary quantum computation,” he said.

Quantum-physical processes have been observed elsewhere in the biological realm, most notably in compass cells that allow birds to navigate by Earth’s geomagnetic fields. Researchers have also proposed roles for quantum physics in the animal sense of smell and even in the brain. Engels predicts the emergence of an entire field of quantum biology.

“There are going to be some surprises,” said Scholes. “Who knows what else there is to discover?”

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