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June 22, 2006, 5:50 PM CT

Reason Behind Black Holes' Light Shows

Reason Behind Black Holes' Light Shows
A team of astronomers led by the University of Michigan may know how black holes are lighting up the Universe. New data from NASA's Chandra X-ray Observatory show, for the first time, that powerful magnetic fields are the key to these brilliant and startling light shows.

It is estimated that up to half of the total radiation in the universe since the Big Bang comes from material falling towards super-massive black holes, including those powering quasars, the brightest known objects. For decades, researchers have struggled to understand how black holes, the darkest objects in the Universe, can generate such prodigious amounts of radiation.

New X-ray data from Chandra give the first clear explanation for what drives this process: magnetic fields. Chandra observed a black hole system in our galaxy, known as GRO J1655-40 (J1655, for short), where a black hole was pulling material from a companion star into a disk.

"By intergalactic standards, J1655 is in our backyard so we can use it as a scale model to understand how all black holes work, including the monsters found in quasars," said Jon Miller, assistant professor at U-M, whose paper on these results appears in this week's issue of the journal Nature.

If gas in a disk around a black hole loses energy, it will swirl toward the black hole, generating light along the way. Researchers have long thought that magnetic fields may drive this energy loss by generating friction in the gas and driving a wind from the disk that carries momentum outward, in an example of conservation of momentum.........

Posted by: Edwin      Permalink         Source


June 21, 2006, 11:41 PM CT

Electrical Conductivity Helps Locate Septic System Failure

Electrical Conductivity Helps Locate Septic System Failure
An instrument that can measure how well soil conducts electricity also can spot the source of septic system failures without destroying a whole yard with a backhoe.

The instrument, called a non-invasive electromagnetic induction (EMI) sensor, measures electrical conductivity based on the soluble salts, water, temperature and percentage of clay in the soil. Purdue University scientists and his colleagues tested the tool on a failed septic system in northeastern Indiana and found that soil conductivity changes can signal septic failure.

They found that the sensor was capable of collecting soil data that identified problems in the septic tank and septic field trenches, said Brad Lee, a Purdue assistant professor of agronomy. The findings appear in the online journal Vadose Zone, a publication of the Soil Science Society of America.

"One of the big problems of looking for septic system contamination is that homeowners don't want their lawns dug up," Lee said. "The sensor can help researchers locate problems without digging. This is possible because soil contaminated with household waste has a higher electrical conductivity than the readings from the rest of the lawn. The instrument identifies these changes in soil electrical conductivity".

Using the electromagnetic sensor is advantageous because it's portable, it collects data quickly and it can measure down to a number of soil depths, he said. In addition, maps prepared from sensor data can be used to assess building sites, plan future testing, and locate the best sites for sampling and monitoring of soil for possible septic contamination.........

Posted by: John      Permalink         Source


June 21, 2006, 11:24 PM CT

Saturnian Moon Ballet

Saturnian Moon Ballet Many denizens of the Saturn system wear a uniformly gray mantle of darkened ice, but not so for these two most fascinating of moons. The brightest body in the Solar System, Enceladus, is contrasted here against Titan's smoggy golden murk.
The cold, icy orbs of the Saturn system come to life in a slew of new movie clips showing the ringed planet's moons in motion.

In addition to their drama and visual interest, scientists use these movies to refine their understanding of the orbits of Saturn's moons. Engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., use the same images, and the orbital positions of the moons, to help them navigate the Cassini spacecraft, which is nearing the halfway mark of its four-year tour.

Pictures capturing several moons in one frame are often strikingly beautiful, especially when deliberately imaged in red, green and blue spectral filters, which allow scientists to create a color photo. One recent color image shows two of Saturn's most fascinating moons, icy-white Enceladus and orange, haze-enshrouded Titan.

Ironically, what these two moons hold in common gives rise to their starkly contrasting colors. Both bodies are, to varying degrees, geologically active. For Enceladus, its southern polar vents emit a spray of icy particles that coats the small moon, giving it a clean, white veneer. On Titan, as-yet-undefined processes are supplying the atmosphere with methane and other chemicals that are broken down by sunlight, creating the thick yellow-orange haze that suffuses the atmosphere and, over geologic time, falls and coats the surface.........

Posted by: Edwin      Permalink         Source


June 20, 2006, 8:57 PM CT

Cluster Makes An Effervescent Discovery

Cluster Makes An Effervescent Discovery This artist’s impression shows the Earth’s magnetosphere
Space is fizzing. Above our heads, where the Earth's magnetic field meets the constant stream of gas from the Sun, thousands of bubbles of superheated gas are constantly growing and popping.

Their discovery could allow researchers to finally understand the interaction between the solar wind and the Earth's magnetic field.

This exciting new view of near-Earth space has been made possible by ESA's four-spacecraft flotilla, Cluster, and Double Star, ESA's collaborative space mission with China. The spacecraft encounter the bubbles every time they are on the day-lit side of the Earth, at altitudes of between 13 and 19 Earth radii.

The bubbles, known as density holes, are regions of space where the density of gas suddenly falls by ten times but the temperature of the remaining gas leaps from 100 000 ºC to 10 000 000 ºC.

When Cluster first flew through the bubbles, George Parks, University of California, Berkeley, thought that they were just instrumentation glitches. "Then I looked at the data from all four Cluster spacecraft. These anomalies were being observed simultaneously by all the spacecraft. That's when I believed that they were real," says Parks.

Somewhat similar bubbles have occasionally been encountered in the past by other spacecraft. They were called hot flow anomalies but Parks decided the bubbles he saw are significantly different.........

Posted by: Edwin      Permalink         Source


June 20, 2006, 7:46 PM CT

Kodak Wi-Fi digital camera

Kodak Wi-Fi digital camera
Digital cameras are great. You can take a limitless number of pictures, and the immediate ability to look at the quality of pictures I've taken satisfies my urge for instant gratification. It's all good, except that I dislike the process of loading it up onto my computer. Kodak must have heard me.

The Kodak EasyShare One Series WiFi digital cameras offers the choice of 4.0 megapixels or 6.1 megapixels. Both give you WiFi capability with 3x optical zoom, and a 3.1" rotating touch screen. You can store and organize up to 1,500 pictures with 256 MB of internal memory, and can add even more picture capacity with the SD/MMC card expansion slot.

With WiFi capability and the Kodak EasyShare Dock, you'll be able to easily transfer pictures and videos to your computer without USB, connect to the Kodak Gallery and email pictures right from the camera. If you're equipped with the Kodak Photo Printer 500, you'll be able to print wirelessly as well. Also, with the dock, you'll be able to charge your camera in approximately 3.5 hours.

At a price of $299.99 USD, it sure is a nifty little device, and I can say goodbye to the USB transfer!........

Posted by: John      Permalink         Source


June 20, 2006, 7:20 PM CT

Snappy Face Recogniser WebCam

Snappy Face Recogniser WebCam
If you tend to forget your login password very often then now you don't need to burden your brain for so small a thing! Instead, let your handsome face do the trick with the innovative Snappy Face Recogniser. The intelligent webcam with snappy face recogniser allows you to access your computer system using your face.

The webcam's advanced face recognition technology protects your computer and important information from unwanted access. The compact and ultra light webcam features 1.3 megapixel high image resolution. So, all you pretty ladies out there! Don't be careless to put on your pancake make-up from now on!!! The webcam is available for 49.98 pounds.........

Posted by: John      Permalink         Source


June 18, 2006, 6:18 PM CT

MRI For Fuel Cells

MRI For Fuel Cells
As gasoline prices top $3 a gallon in major cities, the drive toward increasing energy efficiency and reducing air pollution has accelerated, and the development of fuel cells has become a major focus worldwide.

Knowing how fuel cells work is key to improving their performance and reducing the cost of their production. Now a research team led by Scott A. Barnett, professor of materials science and engineering at Northwestern University, has produced the first three-dimensional images of the interior of a fuel cell -- providing a new tool for the study and development of fuel cells.

The researchers' three-dimensional reconstruction of a solid oxide fuel cell anode was reported in a paper published this month by the journal Nature Materials. (A solid oxide fuel cell efficiently converts fuels such as hydrogen and natural gas directly into electricity; Barnett's group also recently reported a similar fuel cell that works with a liquid transportation fuel -- iso-octane, a high-purity compound similar to gasoline.).

"Much like magnetic resonance imaging produces a view inside the human body, we now can look inside fuel cells," said Barnett. "The dual-beam focused-ion-beam microscope used in the study provides much higher resolution than an MRI, showing nanometer-scale features. These pictures will help us and other researchers to unravel how fuel cells work so they can eventually be improved and made to work longer without failing".........

Posted by: Nora      Permalink         Source


June 18, 2006, 12:01 AM CT

Mini-planet Systems Get Stranger

Mini-planet Systems Get Stranger A brown dwarf companion (bottom left) was also surrounded by a disc
Mini planetary systems may orbit cosmic objects that are 100 times smaller than our Sun, research suggests.

Discs of gas and dust, the ingredients needed to create such systems, have been seen circling these relatively small objects, dubbed "planemos".

If the discs were capable of evolving larger aggregations of material, it would blur the definition of the word "planet", researchers said.

The work was presented at the American Astronomical Society meeting in Canada.

Cosmic newborns

The study is based on observations from European Southern Observatory (ESO) telescopes. It looked at a number of recently identified planemos (an unofficial term sometimes used to describe planetary mass objects).

Located about 450 light-years away in a star-forming region, four of the objects are just a few million years old, making them cosmic "newborns". They have masses between five and 15 times that of Jupiter. ........

Posted by: Edwin      Permalink         Source


June 18, 2006, 11:44 AM CT

NASA Gives Green Light For Discovery Launch

NASA Gives Green Light For  Discovery Launch Image above: Amid the glow of lights from the fixed and rotating service structures, Space Shuttle Discovery rests on the hardstand of Launch Pad 39B at NASA's Kennedy Space Center. Photo credit: NASA/Ken Thornsley
NASA senior managers on Saturday cleared the Space Shuttle Discovery for a July 1 flight to the International Space Station.

The decision was announced after a lengthy Flight Readiness Review, a traditional meeting in which top NASA managers and engineers set launch dates, determine whether the shuttle's complex array of equipment, support systems and procedures are ready for flight and assess any risks associated with the mission.

"We had two full days of an intensive Flight Readiness Review," said Administrator Michael Griffin. "It was spirited and one of the most open, yet non-adversarial meetings I've seen since returning to NASA".

+ Read Press Release.

William Gerstenmaier, Associate Administrator for Space Operations said "It was a tremendously good review. We were really careful in this. We reviewed everything we could and we think we are ready to go and fly".

"The ice frost ramps were one of the most vigorously discussed items. This [foam loss], is what we expect to see in flight. So when we get this data down, you should not be surprised," continued Gerstenmaier.

The ice/frost ramps are structures made of insulation foam that cover 34 brackets on the outside of the shuttle's external fuel tank. The ramps have been cited as a potential source of foam loss, which could cause damage to the shuttle. The Flight Readiness Review board decided the current design does not pose sufficient risk to delay the upcoming mission while design improvements for later flights are under way.........

Posted by: Edwin      Permalink         Source


June 18, 2006, 11:02 AM CT

From Aerosol Particles To Cloud Droplets

From Aerosol Particles To Cloud Droplets
In spite of diverse origins and composition of aerosol particles in central Europe, their ability to grow into cloud droplets is controlled predominantly by their size.

Clouds play a central role in the Earth's climate system and water cycle. A cloud's behavior depends to a great extent on the number and size of the droplets it is made of. Since each of these droplets requires a seed aerosol particle to grow upon (called cloud condensation nucleus, CCN), it is essential to understand what properties of an aerosol particle allow it to grow into a cloud drop. Basic physical chemistry shows that, to a first approximation, this depends on the number of soluble molecules it contains, which is a function of its size and composition. Given the very diverse origin of atmospheric particles (e.g., sea salt, dust, smoke, and industrial emissions), the complexity of their composition has long been seen as a major obstacle to modeling and predicting aerosol effects on cloud properties and climate.

To separate the effects of size and composition, the scientists of the Max Planck Institute for Chemistry and the University of Mainz divided ambient aerosols into narrow size classes and then determined their chemical composition and ability to grow into cloud drops. They made the measurements in summer 2004, on top of the Kleiner Feldberg in the Taunus Mountains of Gera number of. During the 3-week measurement period, diverse air masses were encountered at the mountaintop station: aged continental air that had accumulated industrial and traffic pollution, marine air masses that had moved in rapidly from the North Atlantic, and fresh pollution from the densely populated and industrialized Rhine-Main area. The aerosol composition was dominated by organic material in all air mass types, followed by ammonium, sulfate and nitrate. Interestingly, in spite of the different histories of the air, the soluble fraction of the particles did not appear to vary all that much.........

Posted by: John      Permalink         Source


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