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| ©Sylvia Liber |
| Professor Ted Bryant with the US film crew at Jones Beach. |
Science & Technology
The BBC and the National Geographic Channel are making a documentary based on the controversial theories of a Wollongong academic, who claims that meteorites hit the earth every 1000 years.
A long-standing scientific belief holds that stars tend to hang out in the same general part of a galaxy where they originally formed. Some astrophysicists have recently questioned whether that is true, and now new simulations show that, at least in galaxies similar to our own Milky Way, stars such as the sun can migrate great distances.
What's more, if our sun has moved far from where it was formed more than 4 billion years ago, that could change the entire notion that there are parts of galaxies - so-called habitable zones - that are more conducive to supporting life than other areas are.
"Our view of the extent of the habitable zone is based in part on the idea that certain chemical elements necessary for life are available in some parts of a galaxy's disk but not others," said Rok Roškar, a doctoral student in astronomy at the University of Washington.
"If stars migrate, then that zone can't be a stationary place."
If the idea of habitable zone doesn't hold up, it would change scientists' understanding of just where, and how, life could evolve in a galaxy, he said.
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| ©Rok Roškar |
| This image is from a computer simulation showing the development and evolution of the disk of a galaxy such as the Milky Way. |
What's more, if our sun has moved far from where it was formed more than 4 billion years ago, that could change the entire notion that there are parts of galaxies - so-called habitable zones - that are more conducive to supporting life than other areas are.
"Our view of the extent of the habitable zone is based in part on the idea that certain chemical elements necessary for life are available in some parts of a galaxy's disk but not others," said Rok Roškar, a doctoral student in astronomy at the University of Washington.
"If stars migrate, then that zone can't be a stationary place."
If the idea of habitable zone doesn't hold up, it would change scientists' understanding of just where, and how, life could evolve in a galaxy, he said.
Oxygen is the most abundant element on Earth, accounting for almost half the planet's mass. Of its three stable isotopes, oxygen 16 (16O, whose nucleus contains eight neutrons) makes up 99.762 percent of oxygen on Earth, while heavier oxygen 17 (17O, with nine neutrons) accounts for just 0.038 percent, and the heaviest isotope, oxygen 18 (18O, with 10 neutrons), makes up 0.2 percent.
Yet minerals in some of the most primitive objects in the solar system, including the meteorites called carbonaceous chondrites, have quite different ratios of oxygen isotopes than on Earth; presumably the rare heavy isotopes occurred in much greater abundances in the early solar system.
"For a chemist, the question of oxygen-isotope ratios is one that could help us understand the origins of the solar system," says Musahid (Musa) Ahmed of Berkeley Lab's Chemical Sciences Division, a beamline scientist at the Chemical Dynamics beamline, 9.0.2, at the Advanced Light Source (ALS). "Why meteoritic oxygen isotope ratios are significantly different from those on Earth has mystified scientists for years."
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| ©NASA |
| The sun in ultraviolet light. When the solar system was forming, the protosun was a potent source of vacuum ultraviolet. |
Yet minerals in some of the most primitive objects in the solar system, including the meteorites called carbonaceous chondrites, have quite different ratios of oxygen isotopes than on Earth; presumably the rare heavy isotopes occurred in much greater abundances in the early solar system.
"For a chemist, the question of oxygen-isotope ratios is one that could help us understand the origins of the solar system," says Musahid (Musa) Ahmed of Berkeley Lab's Chemical Sciences Division, a beamline scientist at the Chemical Dynamics beamline, 9.0.2, at the Advanced Light Source (ALS). "Why meteoritic oxygen isotope ratios are significantly different from those on Earth has mystified scientists for years."
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| ©University of Toronto |
| Young star 1RXS J160929.1-210524 and its faint, planetary mass candidate companion. Blue, green, and red represent images taken in J, H, and Ks, with intensities scaled such that they are proportional to the photon rates inferred from the 2MASS magnitudes of the primary |
University of Toronto astronomers have unveiled what is likely the first picture of a planet around a star similar to the sun.
An international team of scientists predict that our Galaxy, the Milky Way, contains a disk of 'dark matter'. Astronomers Dr Justin Read, Professor George Lake and Oscar Agertz of the University of Zurich, and Dr Victor Debattista of the University of Central Lancashire use the results of a supercomputer simulation to deduce the presence of this disk.
They explain how it could allow physicists to directly detect and identify the nature of dark matter for the first time.
Unlike the familiar 'normal' matter that makes up stars, gas and dust, 'dark' matter is invisible but its presence can be inferred through its gravitational influence on its surroundings. Physicists believe that it makes up 22% of the mass of the Universe (compared with the 4% of normal matter and 74% comprising the mysterious 'dark energy'). But, despite its pervasive influence, no-one is sure what dark matter consists of.
Prior to this work, it was thought that dark matter forms in roughly spherical lumps called 'halos', one of which envelopes the Milky Way. But this 'standard' theory is based on supercomputer simulations that model the gravitational influence of the dark matter alone. The new work includes the gravitational influence of the stars and gas that also make up our Galaxy.
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| ©. Read and O. Agertz |
| A composite image of the dark matter disk (red contours) and the Atlas image mosaic of the Milky Way obtained as part of the Two Micron All Sky Survey (2MASS). |
They explain how it could allow physicists to directly detect and identify the nature of dark matter for the first time.
Unlike the familiar 'normal' matter that makes up stars, gas and dust, 'dark' matter is invisible but its presence can be inferred through its gravitational influence on its surroundings. Physicists believe that it makes up 22% of the mass of the Universe (compared with the 4% of normal matter and 74% comprising the mysterious 'dark energy'). But, despite its pervasive influence, no-one is sure what dark matter consists of.
Prior to this work, it was thought that dark matter forms in roughly spherical lumps called 'halos', one of which envelopes the Milky Way. But this 'standard' theory is based on supercomputer simulations that model the gravitational influence of the dark matter alone. The new work includes the gravitational influence of the stars and gas that also make up our Galaxy.
Researchers say newly discovered bacteria can be used as a biosensor to identify and treat arsenic-contaminated sites.
Scientists have found a microbe living in the extreme conditions of a sub-arctic mine capable of neutralizing highly toxic arsenic.
The researchers from University College London in the United Kingdom said the team had found these hearty extremophiles living on the walls of Giant Mine in northwestern Canada. The bacteria are able to consume arsenic compounds contained in polluted water seeping into the mine.
Scientists have found a microbe living in the extreme conditions of a sub-arctic mine capable of neutralizing highly toxic arsenic.
The researchers from University College London in the United Kingdom said the team had found these hearty extremophiles living on the walls of Giant Mine in northwestern Canada. The bacteria are able to consume arsenic compounds contained in polluted water seeping into the mine.
They are the toughest animals on the planet - and now scientists have discovered that they can even survive in space.
The tiny creatures, known as tardigrades or water bears, are certainly strange-looking with their eight chubby legs, little claws and probing heads.
Some experts have compared their shape with jelly babies or moles but tardigrades they should not be judged by their 'cute' appearance. They are virtually indestructible - they will not die even if they are boiled, frozen, squeezed under pressure or desiccated.
The tiny creatures, known as tardigrades or water bears, are certainly strange-looking with their eight chubby legs, little claws and probing heads.
Some experts have compared their shape with jelly babies or moles but tardigrades they should not be judged by their 'cute' appearance. They are virtually indestructible - they will not die even if they are boiled, frozen, squeezed under pressure or desiccated.
A flash of light that blinded even small telescopes six months ago was the brightest astronomical explosion ever observed - visible to the naked eye despite originating halfway across the universe.
The gamma-ray burst, catalogued as GRB 080319B, was the result of a massive star's explosion 7.5 billion years ago that sent a pencil-beam of intense light on a direct collision course for Earth. It is the only known gamma-ray burst to have had a visible component bright enough to see with the naked eye.
"This was the brightest optical and infrared event that mankind has ever recorded," said Joshua Bloom, an assistant professor of astronomy at the University of California, Berkeley, and first author of an analysis of the event submitted to The Astrophysical Journal (ApJ) less than a week after the burst and accepted this week. "When more of these events are detected, we will open up the possibility of studying the infant universe with this new tool."
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| ©Joshua Bloom/UC Berkeley |
| In the seconds after it first pointed at GRB 080319B, the infrared telescope PAIRITEL was blinded by the brilliant explosion (a). As the gamma-ray burst began to fade, PAIRITEL was able to track the light from the explosion for many hours (b and c). |
The gamma-ray burst, catalogued as GRB 080319B, was the result of a massive star's explosion 7.5 billion years ago that sent a pencil-beam of intense light on a direct collision course for Earth. It is the only known gamma-ray burst to have had a visible component bright enough to see with the naked eye.
"This was the brightest optical and infrared event that mankind has ever recorded," said Joshua Bloom, an assistant professor of astronomy at the University of California, Berkeley, and first author of an analysis of the event submitted to The Astrophysical Journal (ApJ) less than a week after the burst and accepted this week. "When more of these events are detected, we will open up the possibility of studying the infant universe with this new tool."
When an electrical current passes through a wire it emanates heat - a principle that's found in toasters and incandescent light bulbs. Some materials, at low temperatures, violate this law and carry current without any heat loss. But this seemingly trivial property, superconductivity, is now at the forefront of our understanding of physics.
In the journal Science, Andrea Bianchi, a professor in the Department of Physics at the Université de Montréal, and his colleagues show that, contrary to previous belief, superconductivity can induce magnetism, which has raised a new quantum conundrum.
Using the Swiss spallation neutron source (SINQ) of the Paul-Scherrer Institute (PSI) in Villigen, the international research group led by Michel Kenzelmann, a scientist at the Paul Scherrer Institute and professor at the Swiss Federal Institute of Technology Zurich, found a superconductor displaying two fascinating quantum properties. First, the material in the superconducting state shows magnetic order, which is a surprise given how superconductivity and magnetism cannot easily be accommodated in the same material.
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| ©University of Montreal |
| Andrea Bianchi, Department of Physics. |
In the journal Science, Andrea Bianchi, a professor in the Department of Physics at the Université de Montréal, and his colleagues show that, contrary to previous belief, superconductivity can induce magnetism, which has raised a new quantum conundrum.
Using the Swiss spallation neutron source (SINQ) of the Paul-Scherrer Institute (PSI) in Villigen, the international research group led by Michel Kenzelmann, a scientist at the Paul Scherrer Institute and professor at the Swiss Federal Institute of Technology Zurich, found a superconductor displaying two fascinating quantum properties. First, the material in the superconducting state shows magnetic order, which is a surprise given how superconductivity and magnetism cannot easily be accommodated in the same material.
A bizarre but well-established aspect of quantum physics could open up a new era of electronic detectors and imaging systems that would be far more efficient than any now in existence, according to new insights by an MIT leader in the field.
MIT Professor of Mechanical Engineering Seth Lloyd has found that a peculiar quantum-physics property called entanglement can be harnessed to make detectors--similar in principle to radar systems used to track airplanes in flight or ships at sea--that are as much as a million times more efficient than existing systems. In addition, beams of entangled light could be swept across a scene to reconstruct a detailed image, with a similar improvement in efficiency.
The new findings, being reported this week in the journal Science, are purely theoretical, but Lloyd says that laboratory experiments have already proven the feasibility of both the light sources and the detectors needed for such a quantum-based photodetection system, so he anticipates that within a year it should be possible to build a laboratory-scale system to demonstrate the new concept.
"It should be possible to have at least a proof-of-principle demonstration within six months to a year," Lloyd said.
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| ©Paul Kwiat and Michael Reck, University of Vienna |
| Entangled photons. |
MIT Professor of Mechanical Engineering Seth Lloyd has found that a peculiar quantum-physics property called entanglement can be harnessed to make detectors--similar in principle to radar systems used to track airplanes in flight or ships at sea--that are as much as a million times more efficient than existing systems. In addition, beams of entangled light could be swept across a scene to reconstruct a detailed image, with a similar improvement in efficiency.
The new findings, being reported this week in the journal Science, are purely theoretical, but Lloyd says that laboratory experiments have already proven the feasibility of both the light sources and the detectors needed for such a quantum-based photodetection system, so he anticipates that within a year it should be possible to build a laboratory-scale system to demonstrate the new concept.
"It should be possible to have at least a proof-of-principle demonstration within six months to a year," Lloyd said.
