Cutting Soot Emissions: Fastest, Most Economical Way to Slow Global Warming?

Reducing soot emissions from diesel engines and other sources could slow melting of sea ice in the Arctic faster and more economically than any other quick fix, new research suggests. (Credit: © lustil / Fotolia)

Science Daily  — A new study of dust-like particles of soot in the air -- now emerging as the second most important, but previously overlooked, factor in global warming -- provides fresh evidence that reducing soot emissions from diesel engines and other sources could slow melting of sea ice in the Arctic faster and more economically than any other quick fix, a scientist reported in Denver, Colorado on August 31, 2011.

In a presentation at the 242nd National Meeting & Exposition of the American Chemical Society (ACS), Mark Z. Jacobson, Ph.D., cited concerns that continued melting of sea ice above the Arctic Circle will be a tipping point for Earth's climate, a point of no return. That's because the ice, which reflects sunlight and heat back into space, would give way to darker water that absorbs heat and exacerbates warming. And there is no known way to make the sea refreeze in the short term.

Jacobson's calculations indicate that controlling soot could reduce warming above parts of the Arctic Circle by almost 3 degrees Fahrenheit within 15 years. That would virtually erase all of the warming that has occurred in the Arctic during the last 100 years.

"No other measure could have such an immediate effect," said Jacobson, who is with Stanford University. "Soot emissions are second only to carbon dioxide (CO₂) in promoting global warming, but its effects have been underestimated in previous climate models. Consequently, soot's effect on climate change has not been adequately addressed in national and international global warming legislation. Soot emissions account for about 17 percent of global warming, more than greenhouse gases like methane. Soot's contribution, however, could be reduced by 90 percent in 5-10 years with aggressive national and international policies."

Soot or "black carbon" consists of particles, nearly invisible on an individual basis, released in smoke from combustion of fossil fuels and biofuels. Major sources include exhaust from diesel cars, buses, trucks, ships, aircraft, agricultural machines, construction equipment and the wood/animal dung fires that hundreds of millions of people in developing countries use for used for cooking and heating. Black carbon particles become suspended in the atmosphere and absorb sunlight, just like a black t-shirt on a sunny day. The particles then radiate that heat back into the air around it. Black carbon also can absorb light reflected from Earth's surface, which helps make it such a potent warming agent.

The good news is that decreasing soot could have a rapid effect, Jacobson said. Unlike carbon dioxide, which remains in the atmosphere for years, soot disappears within a few weeks, so that there is no long-term reservoir with a continuing warming effect. And the technology for controlling black carbon, unlike that for controlling CO₂, already is available at relatively modest cost. Diesel particulate filters, for instance, can remove soot from car and truck exhaust. Government and other agencies also are trying to introduce low-soot cookstoves in developing countries. "Converting gasoline- and diesel-burning cars and trucks to electric or hydrogen vehicles and reducing emissions from diesel generators could have an immediate effect on warming," according to Jacobson.

Jacobson, who developed the first detailed climate model to include the global effects of soot, reported on use of the model to gain new insights into the effects of soot particles trapped inside and between the water droplets that make up clouds. Previous research on black carbon and climate overlooked that topic. Jacobson said the information is important because black carbon within clouds makes the clouds "burn off" and disappear over heavily polluted urban and other areas. Climate models that ignore this "cloud absorption" phenomenon underestimate the effects of black carbon on climate.

The Star That Should Not Exist

At the center of this picture is a very unremarkable looking faint star, too faint to be seen through all but the largest amateur telescopes. This ancient star, in the constellation of Leo (The Lion), is called SDSS J102915+172927 and has been found to have the lowest amount of elements heavier than helium of all stars yet studied. It has a mass smaller than that of the Sun and is probably more than 13 billion years old. (Credit: ESO/Digitized Sky Survey 2)

Science Daily — A faint star in the constellation of Leo (The Lion), called SDSS J102915+172927 [1], has been found to have the lowest amount of elements heavier than helium (what astronomers call "metals") of all stars yet studied. It has a mass smaller than that of the Sun and is probably more than 13 billion years old.

"A widely accepted theory predicts that stars like this, with low mass and extremely low quantities of metals, shouldn't exist because the clouds of material from which they formed could never have condensed," [2] said Elisabetta Caffau (Zentrum fur Astronomie der Universitat Heidelberg, Germany and Observatoire de Paris, France), lead author of the paper. "It was surprising to find, for the first time, a star in this 'forbidden zone', and it means we may have to revisit some of the star formation models."

The team analysed the properties of the star using the X-shooter and UVES instruments on the VLT [3]. This allowed them to measure how abundant the various chemical elements were in the star. They found that the proportion of metals in SDSS J102915+172927 is more than 20 000 times smaller than that of the Sun [4][5].

"The star is faint, and so metal-poor that we could only detect the signature of one element heavier than helium -- calcium -- in our first observations," said Piercarlo Bonifacio (Observatoire de Paris, France), who supervised the project. "We had to ask for additional telescope time from ESO's Director General to study the star's light in even more detail, and with a long exposure time, to try to find other metals."

Cosmologists believe that the lightest chemical elements -- hydrogen and helium -- were created shortly after the Big Bang, together with some lithium [6], while almost all other elements were formed later in stars. Supernova explosions spread the stellar material into the interstellar medium, making it richer in metals. New stars form from this enriched medium so they have higher amounts of metals in their composition than the older stars. Therefore, the proportion of metals in a star tells us how old it is.

"The star we have studied is extremely metal-poor, meaning it is very primitive. It could be one of the oldest stars ever found," adds Lorenzo Monaco (ESO, Chile), also involved in the study.

Also very surprising was the lack of lithium in SDSS J102915+172927. Such an old star should have a composition similar to that of the Universe shortly after the Big Bang, with a few more metals in it. But the team found that the proportion of lithium in the star was at least fifty times less than expected in the material produced by the Big Bang.

"It is a mystery how the lithium that formed just after the beginning of the Universe was destroyed in this star." Bonifacio added.

The researchers also point out that this freakish star is probably not unique. "We have identified several more candidate stars that might have metal levels similar to, or even lower than, those in SDSS J102915+172927. We are now planning to observe them with the VLT to see if this is the case," concludes Caffau.

Notes

[1] The star is catalogued in the Sloan Digital Sky Survey or SDSS. The numbers refer to the object's position in the sky.

[2] Widely accepted star formation theories state that stars with a mass as low as SDSS J102915+172927 (about 0.8 solar masses or less) could only have formed after supernova explosions enriched the interstellar medium above a critical value. This is because the heavier elements act as "cooling agents," helping to radiate away the heat of gas clouds in this medium, which can then collapse to form stars. Without these metals, the pressure due to heating would be too strong, and the gravity of the cloud would be too weak to overcome it and make the cloud collapse. One theory in particular identifies carbon and oxygen as the main cooling agents, and in SDSS J102915+172927 the amount of carbon is lower than the minimum deemed necessary for this cooling to be effective.

[3] X-shooter (http://www.eso.org/public/news/eso0920/) and UVES (http://www.eso.org/sci/facilities/paranal/instruments/uves/) are VLT spectrographs -- instruments used to separate the light from celestial objects into its component colours and allow detailed analysis of the chemical composition. X-shooter can capture a very wide range of wavelengths in the spectrum of an object in one shot (from the ultraviolet to the near-infrared). UVES is the Ultraviolet and Visual Echelle Spectrograph, a high-resolution optical instrument.

[4] The star HE 1327-2326, discovered in 2005, has the lowest known iron abundance, but it is rich in carbon. The star now analysed has the lowest proportion of metals when all chemical elements heavier than helium are considered.

[5] ESO telescopes have been deeply involved in many of the discoveries of the most metal-poor stars. Some of the earlier results were reported in eso0228 (http://www.eso.org/public/news/eso0920/) and eso0723 (http://www.eso.org/public/news/eso0723/) and the new discovery shows that observations with ESO telescopes have let astronomers make a further step closer to finding the first generation of stars.

[6] Primordial nucleosynthesis refers to the production of chemical elements with more than one proton a few moments after the Big Bang. This production happened in a very short time, allowing only hydrogen, helium and lithium to form, but no heavier elements. The Big Bang theory predicts, and observations confirm, that the primordial matter was composed of about 75% (by mass) of hydrogen, 25% of helium, and trace amounts of lithium.

More information

This research was presented in a paper, "An extremely primitive halo star," by Caffau et al. to appear in the 1 September 2011 issue of the journal Nature.

The team is composed of Elisabetta Caffau (Zentrum fur Astronomie der Universitat Heidelberg [ZAH], Germany and GEPI -- Observatoire de Paris, Universite Paris Diderot, CNRS, France [GEPI]), Piercarlo Bonifacio (GEPI), Patrick François (GEPI and Universite de Picardie Jules Verne, Amiens, France), Luca Sbordone (ZAH, Max-Planck Institut fur Astrophysik, Garching, Germany, and GEPI), Lorenzo Monaco (ESO, Chile), Monique Spite (GEPI), François Spite (GEPI), Hans-G. Ludwig (ZAH and GEPI), Roger Cayrel (GEPI), Simone Zaggia (INAF, Osservatorio Astronomico di Padova, Italy), François Hammer (GEPI), Sofia Randich (INAF, Osservatorio Astrofisico di Arcetri, Firenze, Italy), Paolo Molaro (INAF, Osservatorio Astronomico di Trieste, Italy), and Vanessa Hill (Universite de Nice-Sophia Antipolis, Observatoire de la Cote d'Azur, CNRS, Laboratoire Cassiopee, Nice, France).

You Will Actually Be Able to Buy Sony's Crazy 3-D Head-Mounted Display

By Dan Nosowitz

Sony HMZ-T1 Sony

We caught a preview of Sony's odd, space-agey head-mounted viewer (appealingly named the HMZ-T1) back at CES in January, but we were pretty surprised to learn that not only is it not a mere demo, Sony's actually planning on, like, putting the thing in stores, where you can exchange currency for it and then take it home. Sony claims it offers an incredibly immersive 3-D experience, better than any TV. We've now played with it twice, and in some ways, that's true.

The idea here is for a personal, extremely high-definition 3-D display. It looks something like a visor, and has two small screens (one in front of each eye) along with non-replaceable headphones. A cable, both for power and data, runs from the headset to a small black box, about the size of a Nintendo Wii, which in turn plugs into any gadget you want (though Sony would undoubtedly prefer you use a PS3 or Blu-ray player). It'll cost somewhere between $750 and $800 when it's released this fall, but the experience--for one person--should be a bargain, compared to buying a high-end 3-D HDTV and stereo.

The HMZ-T1 is particularly notable because its screens use OLED displays--OLEDs are increasingly used for smaller gadgets like smartphones, due to the screen tech's clarity and deep, dark blacks, but get exponentially more expensive the bigger they get, to the point where the biggest OLED displays are only around 30 inches big and cost tens of thousands of dollars. But the HMZ-T1 uses two 0.7-inch OLEDs, close enough to your face that it appears about the same size as a 150-inch screen at 12 feet--basically, you can't see anything but the screen, and that screen is a very premium OLED.

Sound comes in the form of built-in headphones that slide down from the headset, providing 5.1 surround sound. In our previews, they sounded pretty good, and were comfortable enough, but keep in mind that you're stuck with these--there's no way to use your own headphones, let alone plug into a stereo.

So how does it feel to watch a movie or play a video game with the display strapped to your face? Mostly okay, really, with a few moments of "this feels weird." The 3-D is some of the better quality I've come across on a home system, though I did come away with a slight headache (admittedly, I'm particularly susceptible to 3-D-induced pain). The headset itself is pretty heavy, especially on the nose, where too much of the weight rests--I'm not sure how it'd fare for a two-hour movie. But the back is adjustable, and others seemed to find it more comfortable than I did.

What I wonder is who this is for--it can only be used by one person, and it's kind of expensive for that. It's really best suited--like 3-D itself--for video games, especially of the 3-D variety. It's extremely immersive; you can't see anything besides the screen, or hear anything besides what's coming out of your headphones, which is great for gaming. At the same time, though, it's extremely unnerving to move your head and find that the entire screen moves with you. You don'tneed to move your head, since you have a perfect view of the entire screen, but it's a natural reaction, and it broke the immersive spell every time. It's also chained by its power/data cord to a set-top box, so forget about blindly roaming around your house or even taking it on a plane unless you're prepared to set up a power strip with several full-sized pieces of home A/V equipment.

The HMZ-T1 lands in Japan on November 11th, with no word just yet on availability elsewhere.

Japanese Researchers Develop a Way to Turn Biological Tissue Transparent

Can be used to study brain function, or just to look cool

By Rebecca Boyle

Mouse Embryos This photo shows two mouse embryos. The clear one at right has been rendered transparent by a new chemical reagent developed by Japanese researchers. RIKEN

All the new breakthroughs in microscopy we’ve seen recently are designed to help scientists see deeper, inside individual cells and into the depths of the brain. Of course, this would be easier to do if there wasn’t a bunch of other tissue blocking the cells you want to see. Japanese researchers have a new solution: Make it all transparent.

A new chemical reagent makes the brain see-through, allowing fluorescent tags to light up neurons and blood vessels deep inside. This enables 3-D images of entire structures, without having to cut anything away or divide anything into smaller sections.

It doesn’t work on living tissue, at least not yet — researchers at RIKEN, Japan’s major research institute, are investigating another, milder reagent that could allow them to study live tissue in this way.

The reagent, called Scale, has specific clarifying properties that do not alter the overall shape or proportion of the sample being washed, according to a news release from RIKEN. First you would have to genetically modify the sample by adding fluorescent proteins to tag certain cells. While it turns the tissue transparent, the Scale method also prevents decreasing the intensity of those fluorescent signals. So once the tissue is washed with Scale, researchers can see the fluorescent proteins flashing.

The fluorescent tags have made it possible to visualize brain regions at a depth of several millimeters, far better than before, and to reconstruct neural networks, RIKEN says. Atsushi Miyawaki and his team at the RIKEN Brain Science Institute have already used it to study neuronal networks among the cerebral cortex, hippocampus and white matter of mouse brains.

It can work on several other tissues besides the brain, the researchers say — they plan to try Scale on the heart, muscles and kidneys, and on tissues from primate and human biopsy samples. The work was published this week in Nature Neuroscience.

Nuclei in the Brain: This image shows nuclei of proliferating neural stem cells (green) and blood vessels (red) tunneling into the transparent hippocampus. The green signal comes from a fluorescent marker. RIKEN

The World's First Airport Dedicated Strictly to Unmanned Drones Will Open in Wales

By Clay Dillow

The British Army's Watchkeeper Drone The Watchkeeper is just one of many military drones the UK government will host at its new Wales-based airport for unmanned aerial systems. Bthebest viaWikimedia

At AUVSI’s unmanned systems conference a couple of weeks ago, the FAA paid a good deal of lip service to the idea of integrating robotic, unmanned aircraft into the national airspace. Then they basically told those of us in the crowd that they would have the regulations ready by 2025 (notably, the speakers didn’t pause for applause at this time). But not every government is being so patient. The world’s first airport designed specifically for unmanned aircraft--boasting a 4,100-foot runway, is opening in Wales, UK, as a first step in getting UAVs and manned aircraft working together in the same airspace.

The UK’s Civilian Aviation Authority is wasting no time dedicating some airspace to unmanned aircraft, designating a 500-square-mile swath of rural Wales and the Irish Sea to the development and flight of unmanned systems. The site is not restricted; general aviation and military flights will still proceed through the airspace as normal, giving the UK--and any companies that care to involve themselves in the future of flight--a space to work on their systems in real general aviation airspace.

That’s huge for both makers of unmanned systems and the UK. The U.S. is slowly coming around to the idea that un-piloted commercial and civilian aircraft are the future of our skies, but thus far there exists no place where they can be developed in an integrated way. A few states like Oklahoma and Oregon have designated some airspace for UAV development, but flights have to be cleared with the FAA weeks in advance. Otherwise, drone aircraft have to be flown under 400 feet and within the operator’s line of sight.

In other words, advanced unmanned commercial and military systems might as well have nowhere to fly at all. In the meantime, by not dragging its feet for another fifteen years, the UK will draw unmanned systems developers that are serious about integrating their robotic systems into a national airspace to its shores for development and testing. Bravo, FAA, bravo.

Chinese Scientists Plan to Pull an Asteroid into Orbit Around Earth

By Clay Dillow

Pictured: Humans Tempting God to Smite Them Hexi Baoyin, Yang Chen, Junfeng Li via arXiv

Last week Chinese scientists wanted to divert an asteroid away from Earth. This week, they want to pull one into orbit around the Earth. What’s possible objections could anyone have to this idea?

The notion stems from a phenomenon the researchers from Tsinghua University in Beijing noticed from time to time with Jupiter. Every now and then our solar systems biggest planet pulls in an object from space, which orbits the planet for a time before jetting off into interplanetary space again.

We could do something similar with a number of near earth objects (NEOs) that will pass near Earth in the coming years and decades. None of these objects will pass close enough to be naturally captured by Earth’s gravity, but a few will come so close that a small nudge in the right direction would put them in orbit--likely a temporary orbit--around Earth.

The idea isn’t simply to flirt with cataclysmic danger, but to bring a small object (they suggest a 10-meter object called 2008EA9 that will pass nearby in 2049) into a loop around the Earth so we can study it closely for a few years. If we can get the art of capturing asteroids orbitally down to a science, we could use it to temporarily make asteroids into Earth-bound satellites (orbiting at about twice the distance of the moon), mine them for minerals, and then send them on their ways.

Read the paper at arXiv.

Researchers Use Brain Scans to Translate Thoughts Into Words

If a picture is worth 1,000 words, how many words make up a thought?

By Rebecca Boyle

Word Associations Color-coded figures illustrate the probability of words within a Wikipedia article about the object actually being associated with the object. The more red a word is, the more likely a person is to associate it, in this case, with "cow." On the other hand, bright blue suggests a strong correlation with "carrot." Black and grey "neutral" words had no specific association or were not considered at all.Francisco Pereira/via Princeton University

A new study that matches words with brain activity patterns could help neuroscientists understand how people think about abstract, complex concepts, researchers say. It lends aphysiological definition to the concept of higher thinking, using functional magnetic resonance imaging and a computer program that condensed 3,500 Wikipedia articles.

Researchers at Princeton University looked at fMRI scans to identify brain regions that were activated when participants thought about certain objects, like a carrot or a house. Then the team generated a list of topics that were also associated with those words. They looked at the same fMRI scans to determine the brain activity that was shared by the words within each topic, as aPrinceton news release puts it. For instance, thoughts about the idea of “furniture” shared similar patterns with words like “table,” “desk” and “chair.”

Once they could tell the fMRI activity that would be sparked by a particular topic, the researchers were able to look at the brain activity alone and extrapolate what the person was thinking about. If a scientist studying brain scans spotted the neural patterns corresponding to “chair,” he could tell that the person was thinking about furniture.

“Whatever subject matter is on someone's mind — not just topics or concepts, but also emotions, plans or socially oriented thoughts — is ultimately reflected in the pattern of activity across all areas of his or her brain," said the team’s senior researcher, Matthew Botvinick, an associate professor in Princeton's Department of Psychology and in the Princeton Neuroscience Institute.

The researchers started out with brain scans from a 2008 word association study, in which participants were shown a picture and a word of five objects in 12 categories. The participants had been asked to visualize the object for three seconds, and the fMRI recorded their neural activity. Then the Princeton researchers came up with a list of their own topics with which to characterize this fMRI data. They used a computer program to condense 3,500 Wikipedia articles about objects — like an airplane, heroin, birds and manual transmission. The program came up with 40 topics to which these things could relate — i.e. aviation, drugs, animals or machinery. (Their full paper is available online for those interested in the specific methods.)

They arranged the fMRI scans by subject matter, and were ultimately able to tell the general topic on a person’s mind. It was harder to pick out an individual object, however, the Princeton news office explains. The eventual goal is to translate brain activity patterns into the correct words to fully describe thoughts, the researchers say.

This could have applications for helping people with disabilities, for whom brain scans might be able to elucidate their thinking more effectively than pictures. The research appears in the journalFrontiers in Human Neuroscience.