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| ©SPL |
| Spintronics harnesses the spin of sub-atomic particles. |
Science & Technology
Scientists funded by the Air Force Office of Scientific Research have used a single photon technique to observe the evolution of individual electron spins in semiconductor nanostructures.
Two Russian astronauts aboard the International Space Station have made a daring spacewalk to repair their Soyuz descent capsule, Russian mission control said on Friday.
Sergei Volkov and Oleg Kononenko managed to remove an explosive bolt from the capsule, one of 10 used to separate two parts of the module during reentry, fixing a problem that had led to rough landings for two previous crews.
Sergei Volkov and Oleg Kononenko managed to remove an explosive bolt from the capsule, one of 10 used to separate two parts of the module during reentry, fixing a problem that had led to rough landings for two previous crews.
When observing with the GEMINI telescopes, two astronomers from Brazil and the United States discovered for the first time asteroids that are similar to "ordinary chondrites", the most common meteorites found on Earth. Until now, astronomers have failed to identify their asteroidal sources because of the various geologic processes that occur after the meteorites are ejected from their asteroidal parent body. This discovery is being published this week in Astronomy & Astrophysics.
Astronomy & Astrophysics is publishing the first discovery by T. Mothé-Diniz (Brazil) and D. Nesvorný (USA) of asteroids with a spectrum similar to that of ordinary chondrites, the meteoritic material that most resembles the composition of our Sun. Most of the meteorites that we collect on Earth come from the main belt of asteroids located between Mars and Jupiter [1]. They were ejected from their asteroidal "parent body" after a collision, were injected into a new orbit, and they finally felt onto the Earth. Meteorites are a major tool for knowing the history of the solar system because their composition is a record of past geologic processes that occurred while they were still incorporated in the parent asteroid. One fundamental difficulty is that we do not know exactly where the majority of meteorite specimens come from within the asteroidal main belt. For many years, astronomers failed to discover the parent body of the most common meteorites, the ordinary chondrites that represent 75% of all the collected meteorites.
Astronomy & Astrophysics is publishing the first discovery by T. Mothé-Diniz (Brazil) and D. Nesvorný (USA) of asteroids with a spectrum similar to that of ordinary chondrites, the meteoritic material that most resembles the composition of our Sun. Most of the meteorites that we collect on Earth come from the main belt of asteroids located between Mars and Jupiter [1]. They were ejected from their asteroidal "parent body" after a collision, were injected into a new orbit, and they finally felt onto the Earth. Meteorites are a major tool for knowing the history of the solar system because their composition is a record of past geologic processes that occurred while they were still incorporated in the parent asteroid. One fundamental difficulty is that we do not know exactly where the majority of meteorite specimens come from within the asteroidal main belt. For many years, astronomers failed to discover the parent body of the most common meteorites, the ordinary chondrites that represent 75% of all the collected meteorites.
Macedonian archaeologists say they have discovered a well-preserved statue of the goddess of love in the ruins of an ancient Roman city near Skopje, Macedonia.
A new, compact way to collect sunlight from windows and focus it to generate more electricity could make those multiple expensive rooftop solar panels a thing of the past.
The solar panels that cover the tops of some buildings today contain photovoltaic cells that convert sunlight into electricity. Unlike burning coal, collecting and converting solar energy releases no greenhouse gases, which warm the atmosphere. Limited efficiency and high construction costs have kept solar from producing more than about 0.07 percent of U.S. energy needs in 2007, according to figures from the U.S. Department of Energy.
Solar concentrators can be used to increase the electrical power obtained from the photovoltaic cells. But most concentrators in use today "track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain," said MIT's Marc A. Baldo, who led the team that created the new type of solar concentrator.
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| ©Nicolle Rager Fuller, NSF |
| An artist's representation shows how a cost effective solar concentrator could help make existing solar panels more efficient. |
The solar panels that cover the tops of some buildings today contain photovoltaic cells that convert sunlight into electricity. Unlike burning coal, collecting and converting solar energy releases no greenhouse gases, which warm the atmosphere. Limited efficiency and high construction costs have kept solar from producing more than about 0.07 percent of U.S. energy needs in 2007, according to figures from the U.S. Department of Energy.
Solar concentrators can be used to increase the electrical power obtained from the photovoltaic cells. But most concentrators in use today "track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain," said MIT's Marc A. Baldo, who led the team that created the new type of solar concentrator.
Think you have trouble getting rid of the clutter in your living room? After more than 50 years of launching rockets and satellites into space, the human race now has to deal with the clutter left behind -- or is it "above"? Dead satellites, spent rocket stages, paint flakes, and coolant from nuclear-powered satellites continue to orbit the Earth at ultrahigh velocities.
It's a serious subject. Space debris threatens the lives of astronauts and the launch of new satellites today, says Dr. Noam Eliaz, Head of the Biomaterials and Corrosion Laboratory at the School of Mechanical Engineering at Tel Aviv University. An expert in materials science and engineering, Dr. Eliaz is working with a team at Soreq NRC to create and test new materials to make the heavens safer for satellites and astronauts alike.
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| ©Tel Aviv University |
It's a serious subject. Space debris threatens the lives of astronauts and the launch of new satellites today, says Dr. Noam Eliaz, Head of the Biomaterials and Corrosion Laboratory at the School of Mechanical Engineering at Tel Aviv University. An expert in materials science and engineering, Dr. Eliaz is working with a team at Soreq NRC to create and test new materials to make the heavens safer for satellites and astronauts alike.
Astronomers have uncovered an extreme stellar machine -- a galaxy in the very remote universe pumping out stars at a surprising rate of up to 4,000 per year. In comparison, our own Milky Way galaxy turns out an average of just 10 stars per year.
The discovery, made possible by several telescopes including NASA's Spitzer Space Telescope, goes against the most common theory of galaxy formation. According to the theory, called the Hierarchical Model, galaxies slowly bulk up their stars over time by absorbing tiny pieces of galaxies -- and not in one big burst as observed in the newfound "Baby Boom" galaxy.
"This galaxy is undergoing a major baby boom, producing most of its stars all at once," said Peter Capak of NASA's Spitzer Science Center at the California Institute of Technology, Pasadena. "If our human population was produced in a similar boom, then almost all of the people alive today would be the same age." Capak is lead author of a new report detailing the discovery in the July 10th issue of Astrophysical Journal Letters.
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| ©NASA/JPL-Caltech/Subaru |
| The green and red splotch in this image is the most active star-making galaxy in the very distant universe. |
The discovery, made possible by several telescopes including NASA's Spitzer Space Telescope, goes against the most common theory of galaxy formation. According to the theory, called the Hierarchical Model, galaxies slowly bulk up their stars over time by absorbing tiny pieces of galaxies -- and not in one big burst as observed in the newfound "Baby Boom" galaxy.
"This galaxy is undergoing a major baby boom, producing most of its stars all at once," said Peter Capak of NASA's Spitzer Science Center at the California Institute of Technology, Pasadena. "If our human population was produced in a similar boom, then almost all of the people alive today would be the same age." Capak is lead author of a new report detailing the discovery in the July 10th issue of Astrophysical Journal Letters.
WASHINGTON -- Efforts to harness the energy potential of Earth's ocean winds could soon gain an important new tool: global satellite maps from NASA. Scientists have been creating maps using nearly a decade of data from NASA's QuikSCAT satellite that reveal ocean areas where winds could produce wind energy.
The new maps have many potential uses including planning the location of offshore wind farms to convert wind energy into electric energy. The research, published this week in Geophysical Research Letters, was funded by NASA's Earth Science Division, which works to advance the frontiers of scientific discovery about Earth, its climate and its future.
"Wind energy is environmentally friendly. After the initial energy investment to build and install wind turbines, you don't burn fossil fuels that emit carbon," said study lead author Tim Liu, a senior research scientist and QuikSCAT science team leader at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Like solar power, wind energy is green energy."
The new maps have many potential uses including planning the location of offshore wind farms to convert wind energy into electric energy. The research, published this week in Geophysical Research Letters, was funded by NASA's Earth Science Division, which works to advance the frontiers of scientific discovery about Earth, its climate and its future.
"Wind energy is environmentally friendly. After the initial energy investment to build and install wind turbines, you don't burn fossil fuels that emit carbon," said study lead author Tim Liu, a senior research scientist and QuikSCAT science team leader at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Like solar power, wind energy is green energy."
Most asteroids with moonlets started off as solitary bodies that split in two while sunbathing, new computer simulations suggest.
Once thought to be rare, dozens of binary asteroid systems - kilometre-sized rocks orbited by small moonlets - have been found in the main belt between Mars and Jupiter since the first asteroid pair was spotted by the Galileo spacecraft in 1993. And 15% of all near-Earth asteroids, which cross Earth's orbit, boast satellites.
Various theories have been proposed to explain how they formed. One suggests the pairs were created by collisions between older asteroids, but because of the huge distances between objects in space, such impacts are very rare.
Once thought to be rare, dozens of binary asteroid systems - kilometre-sized rocks orbited by small moonlets - have been found in the main belt between Mars and Jupiter since the first asteroid pair was spotted by the Galileo spacecraft in 1993. And 15% of all near-Earth asteroids, which cross Earth's orbit, boast satellites.
Various theories have been proposed to explain how they formed. One suggests the pairs were created by collisions between older asteroids, but because of the huge distances between objects in space, such impacts are very rare.
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| ©Kevin Walsh/Derek Charles Richardson/UMD |
| Pairs of asteroids can be created from a single parent body that spins so fast due to solar energy that it breaks apart. In new computer simulations, the parent body was modelled as a rubble pile. Loose material near its poles rolled to its equator, then floated off to become a moon |
It is the very symbol of the glory that was Rome. It figures on the badge of the Serie A side, AS Roma. It was used as the emblem of the 1960 Rome Olympics. For Benito Mussolini, Italy's fascist dictator, there was nothing more representative of the might of the empire he hoped to revive than this magnificent, life-size bronze of a she-wolf suckling the city's legendary founders, Romulus and Remus.
Only problem: it was made 1,700-1,800 years later than supposed.
Only problem: it was made 1,700-1,800 years later than supposed.
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| ©Ron Chapple Stock / Corbis |
| A lady never reveals her age ... The Capitoline wolf in Rome. |
