Source: http://news.feedzilla.com/en_us/stories/politics/top-stories/294480908?client_source=feed&format=rss
mike d antoni nba trade rumors desean jackson 2012 ncaa tournament schedule laurent robinson dantoni gillian anderson
Monday, March 25, 2013
Speed of light may not be fixed after all, but rather fluctuates: Ephemeral vacuum particles induce speed-of-light fluctuations
Mar. 25, 2013 ? Two forthcoming European Physical Journal D papers challenge established wisdom about the nature of vacuum. In one paper, Marcel Urban from the University of Paris-Sud, located in Orsay, France and his colleagues identified a quantum level mechanism for interpreting vacuum as being filled with pairs of virtual particles with fluctuating energy values. As a result, the inherent characteristics of vacuum, like the speed of light, may not be a constant after all, but fluctuate.
Meanwhile, in another study, Gerd Leuchs and Luis L. S?nchez-Soto, from the Max Planck Institute for the Physics of Light in Erlangen, Germany, suggest that physical constants, such as the speed of light and the so-called impedance of free space, are indications of the total number of elementary particles in nature.
Vacuum is one of the most intriguing concepts in physics. When observed at the quantum level, vacuum is not empty. It is filled with continuously appearing and disappearing particle pairs such as electron-positron or quark-antiquark pairs. These ephemeral particles are real particles, but their lifetimes are extremely short. In their study, Urban and colleagues established, for the first time, a detailed quantum mechanism that would explain the magnetisation and polarisation of the vacuum, referred to as vacuum permeability and permittivity, and the finite speed of light. This finding is relevant because it suggests the existence of a limited number of ephemeral particles per unit volume in a vacuum.
As a result, there is a theoretical possibility that the speed of light is not fixed, as conventional physics has assumed. But it could fluctuate at a level independent of the energy of each light quantum, or photon, and greater than fluctuations induced by quantum level gravity. The speed of light would be dependent on variations in the vacuum properties of space or time. The fluctuations of the photon propagation time are estimated to be on the order of 50 attoseconds per square meter of crossed vacuum, which might be testable with the help of new ultra-fast lasers.Leuchs and Sanchez-Soto, on the other hand, modelled virtual charged particle pairs as electric dipoles responsible for the polarisation of the vacuum.
They found that a specific property of vacuum called the impedance, which is crucial to determining the speed of light, depends only on the sum of the square of the electric charges of particles but not on their masses. If their idea is correct, the value of the speed of light combined with the value of vacuum impedance gives an indication of the total number of charged elementary particles existing in nature. Experimental results support this hypothesis.
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
Story Source:
The above story is reprinted from materials provided by Springer.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal References:
- Marcel Urban, Fran?ois Couchot, Xavier Sarazin, Arache Djannati-Atai. The quantum vacuum as the origin of the speed of light. The European Physical Journal D, 2013; 67 (3) DOI: 10.1140/epjd/e2013-30578-7
- Gerd Leuchs, Luis L. S?nchez-Soto. A sum rule for charged elementary particles. The European Physical Journal D, 2013; 67 (3) DOI: 10.1140/epjd/e2013-30577-8
Note: If no author is given, the source is cited instead.
Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.
limbaugh aaron smith wilt chamberlain joe arpaio cat in the hat green eggs and ham wiz khalifa and amber rose
Laser empties atoms from the inside out
![[ Back to EurekAlert! ]](http://www.eurekalert.org/images/back2e.gif){kind=small}
Public release date: 25-Mar-2013[ | E-mail |
Share ] Contact: Caron Lett
caron.lett@york.ac.uk
44-019-043-22029
University of York
An international team of plasma physicists has used one of the world's most powerful lasers to create highly unusual plasma composed of hollow atoms.
The experimental work led by scientists from the University of York, UK and the Joint Institute for High Temperatures of Russian Academy of Sciences demonstrated that it is possible to remove the two most deeply bound electrons from atoms, emptying the inner most quantum shell and leading to a distinctive plasma state.
The experiment was carried out using the petawatt laser at the Central Laser Facility at the Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory to further understanding of fusion energy generation, which employs plasmas that are hotter than the core of the Sun.
The results are reported in the journal Physical Review Letters.
A hollow atom occurs when an electron buried in an atom is removed, usually by being hit by another electron, creating a hole while leaving all the other electrons attached. This process creates plasma, a form of ionised gas. An X-ray is released when the hole is filled.
Normally the process involves removing electrons from the outer shells of atoms first and working inwards. The team of scientists demonstrated a new mechanism for creating hollow atoms that involved emptying atoms from the inside out.
The experimental work used an intense laser, which at one petawatt delivers approximately 10,000 times the entire UK national grid, delivered in a thousand-billionth of a second, onto an area smaller than the end of a human hair.
Dr Nigel Woolsey, from the York Plasma Institute, Department of Physics, at the University of York was the Principal Investigator for the experimental work.
Dr Woolsey said: "At such extraordinary intensities electrons move at close to the speed of light and as they move they create perhaps the most intense X-rays ever observed on Earth. These X-rays empty the atoms from the inside out; a most extraordinary observation and one that suggests the physics of these interactions is likely to change, as lasers become more powerful."
Analysis and theoretical work was led by the Los Alamos National Laboratory, USA and Osaka University, Japan.
The analysis showed the mechanism for hollow atom generation was not due to the collision of electrons or driven by the laser photons, but was driven by the resulting radiation field from the interaction.
Lead author Dr James Colgan, from the Los Alamos National Laboratory, said: "The conditions under which the hollow atoms were produced were highly non-equilibrium and the production mechanism was quite surprising. These results indicate that a little-explored region of physics is now starting to become accessible with the unprecedented intensities reached by the world's leading laser facilities."
Co-author Dr Alexei Zhidkov, from Osaka University, said: "This experiment has demonstrated a situation where X-ray radiation dominates the atomic physics in a laser-plasma interaction; this indicates the importance of X-ray radiation generation in our physics description. Future experiments are likely to show yet more dramatic effects which will have substantial implications for diverse fields such as laboratory-based astrophysics."
If the scientific and technological challenges can be overcome, fusion offers the potential for an effectively limitless supply of safe, environmentally friendly energy. The experimental work was designed to further scientists understanding of how intense lasers can create electron beams with speeds close to the speed of light, then use these beams to heat fusion fuel to thermonuclear temperatures.
Co-author Dr Sergey Pikuz, from the Joint Institute for High Temperatures RAS, said: "The measurements, simulations, and developing physics picture are consistent with a scenario in which high-intensity laser technology can be used to generate extremely intense X-ray fields. This demonstrates the potential to study properties of matter under the impact of intense X-ray radiation."
Co-author Rachel Dance, a University of York PhD physics student, said: "This was a very dynamic experiment which led to an unexpected outcome and new physics. The hollow atom diagnostic was set to measure the hot electron beam current generated by the laser, and the results that came out of this in the end, showed us that the mechanism for hollow atom generation, was not collisional or driven by the laser photons, but by the resulting radiation field from the interaction."
###
The UK researchers received funding from the Science and Technology Facilities Council (STFC), the Engineering and Physical Sciences Research Council (EPSRC) and the Royal Society.
[ | E-mail | Share ] ?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Public release date: 25-Mar-2013[ | E-mail |
Share ] Contact: Caron Lett
caron.lett@york.ac.uk
44-019-043-22029
University of York
An international team of plasma physicists has used one of the world's most powerful lasers to create highly unusual plasma composed of hollow atoms.
The experimental work led by scientists from the University of York, UK and the Joint Institute for High Temperatures of Russian Academy of Sciences demonstrated that it is possible to remove the two most deeply bound electrons from atoms, emptying the inner most quantum shell and leading to a distinctive plasma state.
The experiment was carried out using the petawatt laser at the Central Laser Facility at the Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory to further understanding of fusion energy generation, which employs plasmas that are hotter than the core of the Sun.
The results are reported in the journal Physical Review Letters.
A hollow atom occurs when an electron buried in an atom is removed, usually by being hit by another electron, creating a hole while leaving all the other electrons attached. This process creates plasma, a form of ionised gas. An X-ray is released when the hole is filled.
Normally the process involves removing electrons from the outer shells of atoms first and working inwards. The team of scientists demonstrated a new mechanism for creating hollow atoms that involved emptying atoms from the inside out.
The experimental work used an intense laser, which at one petawatt delivers approximately 10,000 times the entire UK national grid, delivered in a thousand-billionth of a second, onto an area smaller than the end of a human hair.
Dr Nigel Woolsey, from the York Plasma Institute, Department of Physics, at the University of York was the Principal Investigator for the experimental work.
Dr Woolsey said: "At such extraordinary intensities electrons move at close to the speed of light and as they move they create perhaps the most intense X-rays ever observed on Earth. These X-rays empty the atoms from the inside out; a most extraordinary observation and one that suggests the physics of these interactions is likely to change, as lasers become more powerful."
Analysis and theoretical work was led by the Los Alamos National Laboratory, USA and Osaka University, Japan.
The analysis showed the mechanism for hollow atom generation was not due to the collision of electrons or driven by the laser photons, but was driven by the resulting radiation field from the interaction.
Lead author Dr James Colgan, from the Los Alamos National Laboratory, said: "The conditions under which the hollow atoms were produced were highly non-equilibrium and the production mechanism was quite surprising. These results indicate that a little-explored region of physics is now starting to become accessible with the unprecedented intensities reached by the world's leading laser facilities."
Co-author Dr Alexei Zhidkov, from Osaka University, said: "This experiment has demonstrated a situation where X-ray radiation dominates the atomic physics in a laser-plasma interaction; this indicates the importance of X-ray radiation generation in our physics description. Future experiments are likely to show yet more dramatic effects which will have substantial implications for diverse fields such as laboratory-based astrophysics."
If the scientific and technological challenges can be overcome, fusion offers the potential for an effectively limitless supply of safe, environmentally friendly energy. The experimental work was designed to further scientists understanding of how intense lasers can create electron beams with speeds close to the speed of light, then use these beams to heat fusion fuel to thermonuclear temperatures.
Co-author Dr Sergey Pikuz, from the Joint Institute for High Temperatures RAS, said: "The measurements, simulations, and developing physics picture are consistent with a scenario in which high-intensity laser technology can be used to generate extremely intense X-ray fields. This demonstrates the potential to study properties of matter under the impact of intense X-ray radiation."
Co-author Rachel Dance, a University of York PhD physics student, said: "This was a very dynamic experiment which led to an unexpected outcome and new physics. The hollow atom diagnostic was set to measure the hot electron beam current generated by the laser, and the results that came out of this in the end, showed us that the mechanism for hollow atom generation, was not collisional or driven by the laser photons, but by the resulting radiation field from the interaction."
###
The UK researchers received funding from the Science and Technology Facilities Council (STFC), the Engineering and Physical Sciences Research Council (EPSRC) and the Royal Society.
[ | E-mail | Share ] ?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Source: http://www.eurekalert.org/pub_releases/2013-03/uoy-lea032513.php
NBA draft 2012 alicia sacramone Don Grady ann curry euro 2012 Colorado Springs Nora Ephron
Healthy Easter Basket Ideas for Babies and Toddlers - Crazy House
Easter is right around the corner and if you have a baby or toddler, you might be looking for healthier Easter Basket options this year. I received an assortment of products from Earth's Best this month and I thought what an amazing way to give your young child a fun yet healthy Easter basket this year! ?With their fun Sesame Street characters, your kids will love getting all of these yummy treats this year and you won't have to worry about them getting too much junk!?
*For Babies who are starting solids, try Earth's Best Baby Food Pouches! They offer products on three different levels depending on your child's age and what stage of solids they are in. For older babies, you can take advantage of some of the canister snacks like Yogurt Puffs, Pop Snax and Happy Snax!? *For preschoolers, we know the Sesame Street Products would be a huge hit! Our favorites include the Letter of the Day Cookies, Snack Bars and Crunchin' Crackers! We also suggest Earth's Best Organic Juice!?Ditch the chocolate bunnies this year and trade them in for healthy snacks that will not lead to a sugar crash! Check out Earth's Best to see all of their wonderful products for the little one's in your family!?
*I am a member of the Earth's Best Blogger Program. I receive no compensation for posts and all opinions are my own*
Source: http://www.crazyhousereviews.com/2013/03/healthy-easter-basket-ideas-for-babies.html
march madness bracket ncaa Chinua Achebe Olympus Has Fallen Miley Cyrus Twerk Marshall Henderson Florida Gulf Coast University
Source: http://totterer-showgirl.blogspot.com/2013/03/healthy-easter-basket-ideas-for-babies.html
Danell Leyva Ye Shiwen OJ Murdock Olympics Live Mens Gymnastics Allison Schmitt Olympic Schedule
Crowd gathers in Damascus to bury slain preacher
DAMASCUS, Syria (AP) ? Supporters of President Bashar Assad gathered in downtown Damascus amid tight security on Saturday for the funeral of one of Syria's best-known clerics who was assassinated in a brazen mosque bombing earlier this week.
Security forces sealed off all roads leading to the eighth century Omayyad Mosque where the funeral for Sheik Mohammad Said Ramadan al-Buti, an 84-year-old pro-government cleric, was held.
Al-Buti, his grandson and 48 others were killed Thursday when a suicide bomber detonated his explosives inside a mosque where al-Buti was giving a religious lesson.
His assassination was a blow to Assad, who vowed Friday to avenge his death, saying he would "purge" the country of the militants behind the attack in the heart of the capital.
Both Assad and the rebels seeking to topple him have blamed each other for the bombing at the mosque.
Al-Buti, the most prominent religious figure killed so far in the 2-year-old conflict, had supported the regime since the early days of Assad's father and predecessor, the late President Hafez Assad, providing legitimacy to their rule. Sunnis are the majority sect in Syria while Assad is from the minority Alawite sect ? an offshoot of Shiite Islam.
Mourners carried al-Buti and his grandson's coffins, draped in white cloth, on their shoulders amid shouts of "God is Great."
Al-Buti was imam of the Omayyad Mosque, a landmark in Damascus. Church bells tolls and mosque minarets in the ancient city blared "God is Great" during the funeral procession.
Syrian state TV said Assad was being represented at the funeral by one of his cabinet ministers.
Al-Buti was being buried in a courtyard at the rear of the mosque near the tomb of Saladin, a medieval Muslim ruler.
In a show of support, a delegation from the Lebanese Shiite Muslim Hezbollah group, a staunch ally of Assad, drove to Damascus for the funeral. A delegation from Iran was also present.
"We will continue on the same path," said Sheik Mohammed Yazbeck, a member Hezbollah's highest decision-making body, the Shura Council. "We will return the blow to the enemies of Syria and the enemies of the nation," he added.
Source: http://news.yahoo.com/crowd-gathers-damascus-bury-slain-preacher-103650912.html
guild wars 2 adrian gonzalez Jerry Nelson Foo Canoodle Isaac path Tropical Storm Isaac path
Sunday, March 24, 2013
Obama withdraws judicial nominee blocked twice by Republicans
By Joseph Ax
NEW YORK (Reuters) - The White House on Friday admitted defeat on its choice of New York lawyer Caitlin Halligan for a judgeship on a powerful appeals court, withdrawing her nomination two weeks after Senate Republicans blocked her for the second time.
President Barack Obama expressed anger that Republicans would not permit a Senate vote even as Halligan appeared to have the support of a majority of senators.
"I am deeply disappointed that even after nearly two and a half years, a minority of senators continued to block a simple up-or-down vote on her nomination," he said in a statement.
Halligan was nominated for the Court of Appeals for the District of Columbia Circuit, widely considered the second most influential U.S. court after the Supreme Court.
The court hears many regulatory cases important to businesses, and the judges on it are often considered for elevation to the high court.
Halligan wrote in a one-paragraph letter to Obama that it was a "tremendous honor" to be nominated but that "the time has come for me to respectfully ask that you withdraw my pending nomination."
Halligan, the general counsel for the Manhattan district attorney's office, did not respond to a request for comment.
In a procedure known as a filibuster, Republicans voted against ending debate on Halligan's nomination in December 2011 and again on March 6.
In both instances, a majority of the Senate voted to end debate and put her nomination to a vote, but she fell short of the 60 votes needed to defeat a filibuster. Democrats control only 55 seats, and legislators largely voted along party lines.
Senator Lisa Murkowski of Alaska was the lone Republican to vote in Halligan's favor on March 6.
Republicans said they were concerned about Halligan's legal "activism" during her time as New York's state solicitor general from 2001 to 2006.
They zeroed in on arguments she made on behalf of the state that gun manufacturers should be held accountable for violent crimes committed with weapons they had made.
Iowa Senator Chuck Grassley, the ranking Republican on the Senate Judiciary Committee, called it an example of "how activists on the far left" use courts to try to remake policy.
The National Rifle Association, a gun rights lobbying group, strongly opposed Halligan's nomination.
In a statement, Democratic Senator Patrick Leahy of Vermont, the judiciary committee chairman, said "narrow, special interests" had influenced Republicans to block Halligan's confirmation.
Halligan became the latest rallying cry for Democrats who claim Republicans have abused the filibuster to prevent Obama from filling several vacancies on the District of Columbia Circuit.
Both parties have blocked judicial nominees over the years, with Democrats moving to stymie certain nominees during the administration of George W. Bush.
Obama is the first president in 50 years who failed to make an appointment to the court during a full term. The 11-seat court has four vacancies, a situation Obama called "unacceptable" on Friday.
(Reporting by Joseph Ax; Editing by Todd Eastham)
Source: http://news.yahoo.com/obama-withdraws-judicial-nominee-blocked-twice-republicans-225913773.html
2012 sports illustrated swimsuit same day flower delivery valentines day cards hallmark grammy winners obama budget woolly mammoth
Subscribe to:
Posts (Atom)