By Jason Palmer
17 November 2010 Last updated at 18:07 GMT
http://www.bbc.co.uk/news/science-environment-11773791
Antimatter atoms have been trapped for the first time, scientists say.
Researchers at Cern, home of the Large Hadron Collider, have held 38 antihydrogen atoms in place, each for a fraction of a second.
Antihydrogen has been produced before but it was instantly destroyed when it encountered normal matter.
The team, reporting in Nature, says the ability to study such antimatter atoms will allow previously impossible tests of fundamental tenets of physics.
The current "standard model" of physics holds that each particle - protons, electrons, neutrons and a zoo of more exotic particles - has its mirror image antiparticle.
The antiparticle of the electron, for example, is the positron, and is used in an imaging technique of growing popularity known as positron emission tomography.
However, one of the great mysteries in physics is why our world is made up overwhelmingly of matter, rather than antimatter; the laws of physics make no distinction between the two and equal amounts should have been created at the Universe's birth.
...
Wednesday, November 17, 2010
Tuesday, November 9, 2010
Violation of a fundamental symmetry of the universe
Physics experiment suggests existence of new particle
November 2, 2010
http://www.physorg.com/news/2010-11-physics-particle.html
(PhysOrg.com) -- The results of a high-profile Fermilab physics experiment involving a University of Michigan professor appear to confirm strange 20-year-old findings that poke holes in the standard model, suggesting the existence of a new elementary particle: a fourth flavor of neutrino.
The new results go further to describe a violation of a fundamental symmetry of the universe asserting that particles of antimatter behave in the same way as their matter counterparts.
Neutrinos are neutral elementary particles born in the radioactive decay of other particles. The known "flavors" of neutrinos are the neutral counterparts of electrons and their heavier cousins, muons and taus. Regardless of a neutrino's original flavor, the particles constantly flip from one type to another in a phenomenon called "neutrino flavor oscillation."
An electron neutrino might become a muon neutrino, and then later an electron neutrino again. Scientists previously believed three flavors of neutrino exist. In this Mini Booster Neutrino Experiment, dubbed MiniBooNE, researchers detected more oscillations than would be possible if there were only three flavors.
"These results imply that there are either new particles or forces we had not previously imagined," said Byron Roe, professor emeritus in the Department of Physics, and an author of a paper on the results newly published online in Physical Review Letters.
"The simplest explanation involves adding new neutrino-like particles, or sterile neutrinos, which do not have the normal weak interactions."
The three known types of neutrino interact with matter primarily through the weak nuclear force, which makes them difficult to detect. It is hypothesized that this fourth flavor would not interact through the weak force, making it even harder to find.
The existence of sterile neutrinos could help explain the composition of the universe, said William Louis, a scientist at Los Alamos National Laboratory who was a doctoral student of Roe's at U-M and is involved in the MiniBooNE experiment.
"Physicists and astronomers are looking for sterile neutrinos because they could explain some or even all of the dark matter of the universe," Louis said. "Sterile neutrinos could also possibly help explain the matter asymmetry of the universe, or why the universe is primarily composed of matter, rather than antimatter."
The MiniBooNE experiment, a collaboration among some 60 researchers at several institutions, was conducted at Fermilab to check the results of the Liquid Scintillator Neutrino Detector (LSND) experiment at Los Alamos National Laboratory, which started in 1990. The LSND was the first to detect more neutrino oscillations than the standard model predicted.
MiniBooNE's initial results several years ago, based on data from a neutrino beam (as opposed to an antineutrino beam), did not support the LSND results. The LSND experiment was conducted using an antineutrino beam, though, so that was the next step for MiniBooNE.
These new results are based on the first three years of data from an antineutrino beam, and they tell a different story than the earlier results. MiniBooNE's antineutrino beam data does support the LSND findings. And the fact that the MiniBooNE experiments produced different results for antineutrinos than for neutrinos especially astounds physicists.
"The fact that we see this effect in antineutrinos and not in neutrinos makes it even more strange," Roe said. "This result means even more serious additions to our standard model would be necessary than had been thought from the first LSND result."
The result seems to violate the "charge-parity symmetry" of the universe, which asserts that the laws of physics apply in the same ways to particles and their counterpart antiparticles. Violations of this symmetry have been seen in some rare decays, but not with neutrinos, Roe said.
While these results are statistically significant and do support the LSND findings, the researchers caution that they need results over longer periods of time, or additional experiments before physicists can rule out the predictions of the standard model.
More information:
-- The paper is called "Event Excess in the MiniBooNE Search for ν̅ μ→ν̅ e Oscillations." It will be published in an upcoming edition of Physical Review Letters: http://prl.aps.org/abstract/PRL/v105/i18/e181801
-- MiniBooNE: http://www-boone.fnal.gov/index.html
Provided by University of Michigan
November 2, 2010
http://www.physorg.com/news/2010-11-physics-particle.html
(PhysOrg.com) -- The results of a high-profile Fermilab physics experiment involving a University of Michigan professor appear to confirm strange 20-year-old findings that poke holes in the standard model, suggesting the existence of a new elementary particle: a fourth flavor of neutrino.
The new results go further to describe a violation of a fundamental symmetry of the universe asserting that particles of antimatter behave in the same way as their matter counterparts.
Neutrinos are neutral elementary particles born in the radioactive decay of other particles. The known "flavors" of neutrinos are the neutral counterparts of electrons and their heavier cousins, muons and taus. Regardless of a neutrino's original flavor, the particles constantly flip from one type to another in a phenomenon called "neutrino flavor oscillation."
An electron neutrino might become a muon neutrino, and then later an electron neutrino again. Scientists previously believed three flavors of neutrino exist. In this Mini Booster Neutrino Experiment, dubbed MiniBooNE, researchers detected more oscillations than would be possible if there were only three flavors.
"These results imply that there are either new particles or forces we had not previously imagined," said Byron Roe, professor emeritus in the Department of Physics, and an author of a paper on the results newly published online in Physical Review Letters.
"The simplest explanation involves adding new neutrino-like particles, or sterile neutrinos, which do not have the normal weak interactions."
The three known types of neutrino interact with matter primarily through the weak nuclear force, which makes them difficult to detect. It is hypothesized that this fourth flavor would not interact through the weak force, making it even harder to find.
The existence of sterile neutrinos could help explain the composition of the universe, said William Louis, a scientist at Los Alamos National Laboratory who was a doctoral student of Roe's at U-M and is involved in the MiniBooNE experiment.
"Physicists and astronomers are looking for sterile neutrinos because they could explain some or even all of the dark matter of the universe," Louis said. "Sterile neutrinos could also possibly help explain the matter asymmetry of the universe, or why the universe is primarily composed of matter, rather than antimatter."
The MiniBooNE experiment, a collaboration among some 60 researchers at several institutions, was conducted at Fermilab to check the results of the Liquid Scintillator Neutrino Detector (LSND) experiment at Los Alamos National Laboratory, which started in 1990. The LSND was the first to detect more neutrino oscillations than the standard model predicted.
MiniBooNE's initial results several years ago, based on data from a neutrino beam (as opposed to an antineutrino beam), did not support the LSND results. The LSND experiment was conducted using an antineutrino beam, though, so that was the next step for MiniBooNE.
These new results are based on the first three years of data from an antineutrino beam, and they tell a different story than the earlier results. MiniBooNE's antineutrino beam data does support the LSND findings. And the fact that the MiniBooNE experiments produced different results for antineutrinos than for neutrinos especially astounds physicists.
"The fact that we see this effect in antineutrinos and not in neutrinos makes it even more strange," Roe said. "This result means even more serious additions to our standard model would be necessary than had been thought from the first LSND result."
The result seems to violate the "charge-parity symmetry" of the universe, which asserts that the laws of physics apply in the same ways to particles and their counterpart antiparticles. Violations of this symmetry have been seen in some rare decays, but not with neutrinos, Roe said.
While these results are statistically significant and do support the LSND findings, the researchers caution that they need results over longer periods of time, or additional experiments before physicists can rule out the predictions of the standard model.
More information:
-- The paper is called "Event Excess in the MiniBooNE Search for ν̅ μ→ν̅ e Oscillations." It will be published in an upcoming edition of Physical Review Letters: http://prl.aps.org/abstract/PRL/v105/i18/e181801
-- MiniBooNE: http://www-boone.fnal.gov/index.html
Provided by University of Michigan
Saturday, November 6, 2010
Hydrogen bond set to be redefined
The hydrogen bond is a wondrous thing. It helps give snowflakes their hexagonal symmetry; binds DNA into a double helix; shapes the three-dimensional forms of proteins; and even raises water's boiling point high enough to make a decent cup of tea. [1]
3 November 2010
http://www.rsc.org/chemistryworld/News/2010/November/03111001.asp
The world authority on chemical nomenclature is preparing to scrap the familiar hydrogen bond definition, in light of recent evidence about its true nature. The International Union of Pure and Applied Chemistry's (Iupac's) Physical and Biophysical Chemistry Division has now published its proposal for the revised definition, and the chemical community has until the end of March 2011 to respond. Barring significant objections, it will be adopted shortly thereafter.
Two key factors are motivating the bonding interaction's redefinition. One is a shift in the traditional view that a hydrogen bond is a purely electrostatic attraction between dipoles or charges on a hydrogen and another, electronegative, atom. Elangannan Arunan, who co-chairs the Iupac group assigned to categorise hydrogen bonds and other intermolecular interactions, highlights that there is a variety of evidence, including nuclear magnetic resonance data, that some electron density is shared between them. 'This shows that the hydrogen bond has a covalent nature,' he says.
The current classification also concentrates on fluorine, oxygen and nitrogen, which Arunan says research has been shown as too simplistic. 'Most existing definitions insist hydrogen is connected to the most electronegative atoms,' he tells Chemistry World. 'That is far from complete now.' Arunan points out that Richard Nelmes at the University of Edinburgh, UK discovered that solid hydrogen sulfide has a hydrogen bonding structure resembling ice. 'That's what really shocked chemists,' he says. ...
http://www.rsc.org/chemistryworld/News/2010/November/03111001.asp
The world authority on chemical nomenclature is preparing to scrap the familiar hydrogen bond definition, in light of recent evidence about its true nature. The International Union of Pure and Applied Chemistry's (Iupac's) Physical and Biophysical Chemistry Division has now published its proposal for the revised definition, and the chemical community has until the end of March 2011 to respond. Barring significant objections, it will be adopted shortly thereafter.
Two key factors are motivating the bonding interaction's redefinition. One is a shift in the traditional view that a hydrogen bond is a purely electrostatic attraction between dipoles or charges on a hydrogen and another, electronegative, atom. Elangannan Arunan, who co-chairs the Iupac group assigned to categorise hydrogen bonds and other intermolecular interactions, highlights that there is a variety of evidence, including nuclear magnetic resonance data, that some electron density is shared between them. 'This shows that the hydrogen bond has a covalent nature,' he says.
The current classification also concentrates on fluorine, oxygen and nitrogen, which Arunan says research has been shown as too simplistic. 'Most existing definitions insist hydrogen is connected to the most electronegative atoms,' he tells Chemistry World. 'That is far from complete now.' Arunan points out that Richard Nelmes at the University of Edinburgh, UK discovered that solid hydrogen sulfide has a hydrogen bonding structure resembling ice. 'That's what really shocked chemists,' he says. ...
by Andy Extance
Previously, the definition suggested hydrogen bonds were ‘electrostatic interactions’, where hydrogen atoms bear a slight positive charge that is attracted by a slightly negatively-charged bonding partner. The new definition allows there to be some element of covalent bonding involved, where electrons are formally shared between the atoms.[1]
[1]. http://blogs.nature.com/news/thegreatbeyond/2010/11/chemists_redefine_hydrogen_bon.html
Friday, November 5, 2010
Billy Graham | God won’t tolerate our evil ways forever
Posted on Thu, Nov. 04, 2010 10:15 PM
http://www.kansascity.com/2010/11/04/2390958/billy-graham-god-wont-tolerate.html
DEAR BILLY GRAHAM: How corrupt will the world have to get before God will decide to intervene and bring it all to an end? Our world seems to be getting worse and worse morally and spiritually, and I just wonder how much longer God is going to put up with it. — A.H.
DEAR A.H.: Yes, the world does seem to be getting worse and worse, both morally and spiritually. We have become like the people of Jeremiah’s day: “Are they ashamed of their loathsome conduct? No, they have no shame at all; they do not even know how to blush” (Jeremiah 6:15). Shortly after Jeremiah uttered those words, God sent judgment upon them and their nation collapsed. That could happen to us.
What is the problem? The problem is that we have left God out of our lives. Whenever any nation does that, the inevitable result is moral and spiritual chaos. Instead of following God’s moral laws, we substitute human lusts and desires in their place. We decide what’s right and wrong, instead of seeking God’s will and God’s law.
Are we nearing the time when God will intervene and Christ will come again to establish his kingdom of perfect justice and righteousness? We don’t know; the Bible warns us against making predictions about this.
God won’t put up with evil forever; some day Christ will come again, and when he does all evil will be judged. Are you ready for that day? You can be, by turning to Christ in repentance and faith and committing your life to him.
© 2010 Tribune Media Services 11/5
http://www.kansascity.com/2010/11/04/2390958/billy-graham-god-wont-tolerate.html
DEAR BILLY GRAHAM: How corrupt will the world have to get before God will decide to intervene and bring it all to an end? Our world seems to be getting worse and worse morally and spiritually, and I just wonder how much longer God is going to put up with it. — A.H.
DEAR A.H.: Yes, the world does seem to be getting worse and worse, both morally and spiritually. We have become like the people of Jeremiah’s day: “Are they ashamed of their loathsome conduct? No, they have no shame at all; they do not even know how to blush” (Jeremiah 6:15). Shortly after Jeremiah uttered those words, God sent judgment upon them and their nation collapsed. That could happen to us.
What is the problem? The problem is that we have left God out of our lives. Whenever any nation does that, the inevitable result is moral and spiritual chaos. Instead of following God’s moral laws, we substitute human lusts and desires in their place. We decide what’s right and wrong, instead of seeking God’s will and God’s law.
Are we nearing the time when God will intervene and Christ will come again to establish his kingdom of perfect justice and righteousness? We don’t know; the Bible warns us against making predictions about this.
God won’t put up with evil forever; some day Christ will come again, and when he does all evil will be judged. Are you ready for that day? You can be, by turning to Christ in repentance and faith and committing your life to him.
© 2010 Tribune Media Services 11/5
Monday, November 1, 2010
China Sets World Record with Fastest Supercomputer
By Ashok Bindra October 28, 2010
http://it.tmcnet.com/topics/it/articles/112245-china-sets-world-record-with-fastest-supercomputer.htm
http://it.tmcnet.com/topics/it/articles/112245-china-sets-world-record-with-fastest-supercomputer.htm
As the race continues to pack more processing power in supercomputers, a Chinese scientific research center set a new performance record for these super machines. Built by the National University of Defense Technology, located at the National Supercomputing Center in Tianjin, a supercomputer was revealed on Thursday at the annual meeting of National High Performance Computing (HPC China 2010) in Beijing.
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