Posted by Benjamin Roudenis on June 28, 2010 0 comments
It is one of the most exquisite views we have ever had of the Earth.
This colourful new map traces the subtle but all pervasive influence the pull of gravity has across the globe.
Known as a geoid, it essentially defines where the level surface is on our planet; it tells us which way is “up” and which way is “down”.
It is drawn from delicate measurements made by Europe’s Goce satellite, which flies so low it comes perilously close to falling out of the sky.
Scientists say the data gathered by the spacecraft will have numerous applications.
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Launched in 2009, the sleek satellite flies pole to pole at an altitude of just 254.9km – the lowest orbit of any research satellite in operation today.
The spacecraft carries three pairs of precision-built platinum blocks inside its gradiometer instrument that sense accelerations which are as small as 1 part in 10,000,000,000,000 of the gravity experienced on Earth.
The ‘standard’ acceleration due to gravity at the Earth’s surface is 9.8m per second squared.
In reality the figure varies from 9.78 (minimum) at the equator to 9.83 (maximum) at the poles.
This has allowed it to map the almost imperceptible differences in the pull exerted by the mass of the planet from one place to the next – from the great mountain ranges to the deepest ocean trenches.
Two months of observations have now been fashioned into what scientists call the geoid.
Posted by Benjamin Roudenis on May 29, 2010 0 comments
Version 1.0 of the STIX Fonts was released May 24, 2010. The initial set of 23 OpenType fonts is now available for download.
Version 1.1, which will include fonts packaged for use with Microsoft Office applications, is scheduled for release by the end of 2010. Version 1.2, which will include Type 1 fonts for use with LaTeX, will follow in 2011.
The mission of the Scientific and Technical Information Exchange (STIX) font creation project is the preparation of a comprehensive set of fonts that serve the scientific and engineering community in the process from manuscript creation through final publication, both in electronic and print formats. Toward this purpose, the STIX fonts will be made available, under royalty-free license, to anyone, including publishers, software developers, scientists, students, and the general public.
The STIX mission will be fully realized when:
Fully hinted PostScript Type 1 and TrueType font sets have been created
All characters/glyphs have been incorporated into Unicode representation or comparable representation and browsers include program logic to fully utilize the STIX font set in the electronic representation of scholarly scientific documents
By making the fonts freely available, the STIX project hopes to encourage the development of applications that make use of these fonts. In particular, the STIX project will create a TeX implementation that TeX users can install and configure with minimal effort.
Posted by Benjamin Roudenis on May 26, 2010 0 comments
At the University of Oklahoma, researchers captured unprecedented high-resolution radar data during the May 10, 2010, tornadoes using one of the most advanced weather radars in the world.
“This unique polarimetric data set is likely to reveal new discoveries about tornado genesis and severe storms for years to come,” said the Director of OU’s Atmospheric Radar Research Center, Robert D. Palmer.
Palmer’s team is currently processing the data using advanced techniques developed at OU and preparing it for distribution.
“The close proximity of the tornadoes to the OU radar has produced data with fine details of the storms never seen before with any radar.”
Located on the OU Research Campus within walking distance of the National Weather Center, the C-band, polarimetric, research weather radar known as OU-PRIME (Polarimetric Radar for Innovations in Meteorology and Engineering) was built to provide OU students and faculty with a platform for research and education in the field of radar meteorology.
Posted by Benjamin Roudenis on May 23, 2010 1 comment
Scientists in China have succeeded in teleporting information between photons further than ever before. They transported quantum information over a free space distance of 16 km (10 miles), much further than the few hundred meters previously achieved, which brings us closer to transmitting information over long distances without the need for a traditional signal.
Quantum teleportation is not the same as the teleportation most of us know from science fiction, where an object (or person) in one place is “beamed up” to another place where a perfect copy is replicated. In quantum teleportation two photons or ions (for example) are entangled in such a way that when the quantum state of one is changed the state of the other also changes, as if the two were still connected. This enables quantum information to be teleported if one of the photons/ions is sent some distance away.
In previous experiments the photons were confined to fiber channels a few hundred meters long to ensure their state remained unchanged, but in the new experiments pairs of photons were entangled and then the higher-energy photon of the pair was sent through a free space channel 16 km long. The researchers, from the University of Science and Technology of China and Tsinghua University in Beijing, found that even at this distance the photon at the receiving end still responded to changes in state of the photon remaining behind. The average fidelity of the teleportation achieved was 89 percent.
Posted by Benjamin Roudenis on May 12, 2010 0 comments
Darryl Carpenter came up with the idea of using hay to soak up the oil spill from the ocean, while driving to a job site last Monday. The next minute he was on the phone with sub-contractor Goodson to ask: “Can you fill a large pan with water and oil, then grab a handful of hay and stir it in? Strain out the hay, then call me back and tell me what’s left in the pan.
Eureka! Carpenter had found a solution. Goodson called back elated to say: “You’re not going to believe how this works!” The hay had soaked up all of the oil in the pan. The water looked clear again. The Walton County Sheriff’s real-time video confirms this.
Donald Sensing at Sense of Events says the numbers just don’t work when you factor the area covered by the oil spill and volume of oil in the water. Visit his webite to see the math.
Posted by Benjamin Roudenis on May 10, 2010 0 comments
Shooting lasers at the sky can make the germ of a raincloud, a new study shows. In an experiment that smacks of science fiction, scientists used a high-powered laser to squeeze water from air, both indoors and out.
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“This is the first time that a laser was used to condense water from both laboratory experiments and from the atmosphere,” says Jérôme Kasparian of the University of Geneva, a coauthor of the study. The work appeared in the May 2 Nature Photonics.
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“It’s just like when you take a shower with hot water — it’s very humid in your bathroom, but it’s not raining,” Kasparian says. Water droplets need a surface to condense on, like a mirror in a bathroom or a speck of dust or pollen in the atmosphere.
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Kasparian and his colleagues tested this idea by shooting a high-powered infrared laser into a cloud chamber. The laser shot extremely short pulses of intense light, which each carrying several terawatts — or a trillion watts — of energy.
The view fogged up immediately. Droplets about 50 micrometers in diameter formed first, and grew to about 80 micrometers in diameter over the next three seconds. “The effect in the cloud chamber was very spectacular and visible by bare eye,” Kasparian says. “We expected an effect, definitely. But that magnitude was pretty much a surprise.”
Next, the researchers took the laser out in the backyard to try it on the sky. They rolled the laser, called “Teramobile” for its terawatt power and its mobility, onto the lawn behind the physics building at the Free University of Berlin on several nights in the fall of 2008. The clouds, if they formed, would be too distant to see with the naked eye, so the team used a second laser to confirm the cloudy view.
“It also worked quite well in the free atmosphere,” Kasparian says. “That was quite surprising, and a very good surprise.”
Posted by Benjamin Roudenis on May 3, 2010 0 comments
A semisubmersible drilling platform called the Deepwater Horizon located about 50 miles southeast of the Mississippi Delta experienced a fire and explosion at approximately 11 p.m. CDT on April 20. Subsequently, oil began spilling out into the Gulf of Mexico and efforts to contain the spill continue today. NASA’s Terra and Aqua satellite imagery has captured the spill in between cloudy days.
On April 29, the MODIS image on the Terra satellite captured a wide-view natural-color image of the oil slick (outlined in white) just off the Louisiana coast. The oil slick appears as dull gray interlocking comma shapes, one opaque and the other nearly transparent. Sunglint — the mirror-like reflection of the sun off the water — enhances the oil slick’s visibility. The northwestern tip of the oil slick almost touches the Mississippi Delta.
Credit: NASA/Earth Observatory/Jesse Allen, using data provided courtesy of the University of Wisconsin’s Space Science and Engineering Center MODIS Direct Broadcast system.
Posted by Benjamin Roudenis on March 7, 2010 0 comments
The magnitude 8.8 quake that slammed central Chile February 27 knocked the entire planet for a loop — literally. The sudden, large-scale movement of tectonic plates that triggered the quake shifted immense masses of rock a few meters closer to Earth’s core, tilting the planet’s axis a few centimeters and imperceptibly shortening the day, analyses indicate.
Disaster struck just after 3:34 a.m. local time, when seismic stresses that had been building for decades, if not centuries, let loose. Rocks along the interface between two tectonic plates slipped past each other a distance of seven to 11 meters, says Jian Lin, a geophysicist at the Woods Hole Oceanographic Institution in Massachusetts.
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The movement of tectonic plates in Chile February 27 has triggered glitches in Earth’s rotation, a new analysis suggests. Sudden subduction of the Nazca plate carried large amounts of mass closer to the center of the Earth — which, conceptually but on a vastly different scale, works like spinning skaters bringing their arms closer to their bodies, says Richard Gross, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. As a result, Earth’s day is now about 1.26 microseconds shorter than it was before the massive quake, Gross estimates.
And because the quake’s shift in mass occurred deep in the Southern Hemisphere, Earth was slightly tipped off balance — a result similar to a spinning skater bringing in one arm but not the other. The planet’s “figure axis,” the line about which the Earth is balanced, shifted about 8 centimeters, Gross notes.
Earth’s axis is constantly wobbling at various frequencies, with some oscillations measuring several meters and taking months to unfold. Forces driving those cycles, including those resulting from winds and ocean currents, act continually across Earth’s surface and often are about a thousand times larger than those generated during the Chilean quake.
Posted by Benjamin Roudenis on February 28, 2010 0 comments
This week Eurocopter unveiled its most recent effort to reduce helicopter noise with the radical-looking Blue Edge rotor blade. The new blade has been tested on one of the company’s EC155 helicopters and was shown to reduce noise 3 to 4 decibels, according to the company.
In addition to the Blue Edge rotor blade, the company also introduced something called Blue Pulse technology. Also designed to reduce helicopter noise, the Blue Pulse system uses three flap modules in the trailing edge of each rotor blade. Piezoelectric motors move actuate the flaps 15 to 40 times per second in reduce the “slap noise” often heard when a helicopter is descending.
Both of these technologies are able to reduce noise by minimizing the blade-vortex interaction of the main rotor on a helicopter. Blade-vortex interaction is the source of the pulsating sound most of us are familiar with when helicopters fly overhead. The noise is created when a rotor blade hits the wake vortex left behind from the blade in front of it.
You can listen to a cockpit recording of Eurocopter’s EC155 with and without the Blue Edge rotor below.
Normally, the entire length of the rotor blade interacts with the vortex of the preceding blade. With the Blue Edge rotors, the double-swept tips of the rotor blade reduce the length of the blade-vortex interaction, and it does it at the tip where the blades are moving the fastest relative to the air. The result is a decrease in the sound produced due of the wake interaction at the tip.
