Relativistic trading: The speed of light isn't fast enough for some market transactions

The profit made on a stock share bought and sold a moment later might only be a penny or so, but if multiplied by millions of shares over the course of a day the money earned can be big.

Holometer experiment to test if the universe is a hologram

Many ideas in theoretical physics involve extra dimensions, but the possibility that the universe has only two dimensions could also have surprising implications. The idea is that space on the ultra-small Planck scale is two-dimensional, and the third dimension is inextricably linked with time. If this is the case, then our three-dimensional universe is nothing more than a hologram of a two-dimensional universe.

Relativity with a human touch

In the famous twin paradox, a sibling who journeys in a fast-moving spacecraft will return home younger than the sibling who remained on Earth. While this apparent slowing of time occurs whenever a body is set in motion, it had been much too small to be detected for movement on a human scale.

Einstein's theory is proved – and it is bad news if you own a penthouse

The world's most accurate clock has neatly shown how right Albert Einstein was 100 years ago, when he proposed that time is a relative concept and the higher you live above sea level the faster you should age.

What Is Time? One Physicist Hunts for the Ultimate Theory

One way to get noticed as a scientist is to tackle a really difficult problem. Physicist Sean Carroll has become a bit of a rock star in geek circles by attempting to answer an age-old question no scientist has been able to fully explain: What is time ?.

Dropping ultra-cold quantum gas down an elevator shaft could help prove Einstein wrong

Scientists have shown that it’s possible to keep sufficiently close tabs on quantum mechanical objects in free fall to tell whether two such objects experience gravity the same way. In 1907, Einstein suggested that if you were in a windowless elevator that was plunging towards Earth in free fall, you would feel the same weightlessness as if you were floating in outer space. This notion, known as the equivalence principle, laid the foundation for general relativity. It explains why a pebble and a piano fall at the same speed if dropped from the same roof, despite their different masses. It’s also a necessary first step toward describing the effects of gravity as curvature in spacetime.

Read More http://www.wired.com/wiredscience/2010/06/quantum-gravity-in-an-elevator/#ixzz0rBEhUpVj

Time travel? Maybe

Einstein and Rosen made a very bold supposition: What if a traveler fell into the mouth of something that looked like a black hole, but rather than being crushed by a singularity at the center of a black hole, instead emerged from another mouth, potentially many light-years from where he or she started ?. This isn't as crazy as it sounds. Einstein's theory of general relativity -- our current working model for how gravity and space work -- has been confirmed with countless experiments. And, as ad hoc as it sounds, an Einstein-Rosen bridge is a perfectly valid solution to the equations of general relativity.

Death of a star in 3D

( PhysOrg.com ) -- Researchers at the Max Planck Institute for Astrophysics in Garching have for the first time managed to reproduce the asymmetries and fast-moving iron clumps of observed supernovae by complex computer simulations in all three dimensions. To this end they successfully followed the outburst in their models consistently from milliseconds after the onset of the blast to the demise of the star several hours later. ( Astrophysical Journal, May 10th, 2010 ).

Viajar a la velocidad de la luz mataría en pocos segundos

Malas noticias para todos los que soñábamos con recorrer la galaxia a velocidades relativísticas. Según parece, al desplazarnos a velocidades cercanas a la de la luz, los escasos átomos de hidrógeno que existen en el espacio  vacío  nos golpearían tan duro como las partículas aceleradas por el Gran Colisionador de Hadrones ( LHC ). Si los científicos de la Universidad Johns Hopkins están en lo cierto,  esos pequeños átomos nos freirían en pocos segundos .

Bad news for all those who dreamed of exploring the galaxy at relativistic speeds. Apparently, the motion at speeds approaching that of light, the few hydrogen atoms that exist in the  vacuum  would hit us as hard as particles accelerated by the Large Hadron Collider ( LHC ). If scientists at Johns Hopkins University are right,  these little atoms will fry us in a few seconds .

A precision measurement of the gravitational redshift by the interference of matter waves

One of the central predictions of metric theories of gravity, such as general relativity, is that a clock in a gravitational potential U will run more slowly by a factor of 1 + U/c², where c is the velocity of light, as compared to a similar clock outside the potential1.

This effect, known as gravitational redshift, is important to the operation of the global positioning system, timekeeping, and future experiments with ultra-precise, space-based clocks ( such as searches for variations in fundamental constants ).

The gravitational redshift has been measured using clocks on a tower, an aircraft and a rocket, currently reaching an accuracy of 7×10^-5.

Here we show that laboratory experiments based on quantum interference of atoms enable a much more precise measurement, yielding an accuracy of 7×10^-9.

Our result supports the view that gravity is a manifestation of space-time curvature, an underlying principle of general relativity that has come under scrutiny in connection with the search for a theory of quantum gravity.

Improving the redshift measurement is particularly important because this test has been the least accurate among the experiments that are required to support curved space-time theories.

NIST’s Second ‘Quantum Logic Clock’ Based on Aluminum Ion is Now World’s Most Precise Clock

Physicists at the National Institute of Standards and Technology (NIST) have built an enhanced version of an experimental atomic clock based on a single aluminum atom that is now the world’s most precise clock, more than twice as precise as the previous pacesetter based on a mercury atom. The new aluminum clock would neither gain nor lose one second in about 3.7 billion years, according to measurements to be reported in Physical Review Letters ( preprint ). The new clock is the second version of NIST’s  quantum logic clock , so called because it borrows the logical processing used for atoms storing data in experimental quantum computing, another major focus of the same NIST research group. ( The logic process is described at http://www.nist.gov/public_affairs/releases/logic_clock/logic_clock.html#background ) The second version of the logic clock offers more than twice the precision of the original.

Quantum Simulation of a Relativistic Particle

Researchers of the Institute for Quantum Optics and Quantum Information (IQOQI) in Innsbruck, Austria, used a calcium ion to simulate a relativistic quantum particle, demonstrating a phenomenon that has not been directly observable so far:

The Zitterbewegung

They have published their findings in the current issue of the journal Nature.

AstroPhysics: La profesora del millón de dólares

La astrofísica Kelly Holley-Bockelman, de la Universidad de Vanderbilt (Estado de Tennessee) ha obtenido la dotación más elevada de la historia para profesores jóvenes, en el área de astronomía, que otorga la Fundación Nacional para la Ciencia de Estados Unidos. Son más de un millón de dólares que destinará a proseguir sus estudios sobre los agujeros negros y a financiar el programa que pretende conseguir que su universidad sea la que produzca más doctores en física y astronomía de las minorías sociales hasta ahora discriminadas.

E=mc2 is Wrong – Einstein’s “Special Relativity” Fundamentally Flawed

Is Albert Einstein’s Special Relativity incompatible with the very equations upon which science’s greatest theory is built ?. New observations made by many scientists and engineers appear to contradict the great German scientist’s ideas. Apparently there are implicit contradictions present within Relativity’s foundational ideas, documents and equations. One individual has even pointed that quotations from the 1905 document and Einstein’s contemporaries as well as interpretations of the Relativity equations clearly and concisely describe a confused and obviously erroneous theory. It is time therefore, for science to update its thinking on this theory with a comprehensive analysis of the history leading up to, during and after that revolutionary year of Special Relativity.

The Dark Attractor: What's Pulling the Milky Way Towards It at 14-Million MPH?

Astronomers have known for years that something unknown apears to be pulling our Milky Way and tens of thousands of other galaxies toward itself at a breakneck 22 million kilometers (14 million miles) per hour. But they couldn’t pinpoint exactly what, or where it is. A huge volume of space that includes the Milky Way and super-clusters of galaxies is flowing towards a mysterious, gigantic unseen mass named mass astronomers have dubbed "The Great Attractor," some 250 million light years from our Solar System. The Milky Way and Andromeda galaxies are the dominant structures in a galaxy cluster called the Local Group which is, in turn, an outlying member of the Virgo supercluster. Andromeda--about 2.2 million light-years from the Milky Way--is speeding toward our galaxy at 200,000 miles per hour...

Stephen Wolfram: The Man Who Cracked The Code to Everything ...

..."The climax of the book is the principle of computational equivalence, which may as well be called "Wolfram's law." After hundreds of pages of laying groundwork, presenting case after case of visual examples where simple rules generate counterintuitively complex results, Wolfram concludes that this phenomenon is overwhelmingly commonplace - it's at the base of everything from morphology to traffic jams. Then he goes further, stating that once a system achieves a certain, easily attainable degree of complexity, it's reached the point of maximum complexity, as measured by the computation required to crank out the end result. Everything at that level of complexity - and that means almost everything you can think of, from human thought to rain hitting pavement - is exactly as complex as anything else."...

Historical Physicist Smackdown Explained: Electric Theory

So, who are the people in yesterday's poll about theoretical physicists, and why should you know them? Three of the four shared a Nobel Prize for developing quantum electrodynamics. In reverse order of voting: Julian Schwinger was an American physicist who came up with a very formal, mathematically rigorous way of describing the behavior of electrons interacting with light. This turns out to be a hard problem, because any attempt to calculate an electron's energy by simple, straightforward means ends up giving an infinite answer. Schwinger helped "renormalize" the theory, getting rid of the infinity with some elegant mathematics.

Michelson–Morley experiment is best yet

Physicists in Germany have performed the most precise Michelson-Morley experiment to date,

confirming that the speed of light is the same in all directions

The experiment, which involves rotating two optical cavities, is about 10 times more precise than previous experiments – and a hundred million times more precise than Michelson and Morley's 1887 measurement.

First Solid Evidence for a Rocky Exoplanet

Mass and density of smallest exoplanet finally measured.

The longest set of HARPS measurements ever made has firmly established the nature of the smallest and fastest-orbiting exoplanet known, CoRoT-7b, revealing its mass as five times that of Earth's. Combined with CoRoT-7b's known radius, which is less than twice that of our terrestrial home, this tells us that the exoplanet's density is quite similar to the Earth's, suggesting a solid, rocky world. The extensive dataset also reveals the presence of another so-called super-Earth in this alien solar system.

Physicist Proposes Solution to Arrow-of-Time Paradox

The laws of physics, which describe everything from electricity to moving objects to energy conservation, are time-invariant. That is, the laws still hold if time is reversed. However, this time reversal symmetry is in direct contrast with everyday phenomena, where  it’s obvious that time moves forward and not backward .

For example, when milk is spilt, it can’t flow back up into the glass, and when pots are broken, their pieces can’t shatter back together. This irreversibility is formalized through the second law of thermodynamics, which says that entropy always increases or stays the same, but never decreases. This contrast has created a reversibility paradox, also called  Loschmidt’s paradox , which scientists have been trying to understand since Johann Loschmidt began considering the problem in 1876. Scientists have proposed many solutions to the conundrum, from trying to embed irreversibility in physical laws to postulating low-entropy initial states.