Charge – that is the degree to which an entity is affected by an external force – comes in all shapes in sizes. Now for the first-time scientists have been able to determine the weak charge of the proton.
The weak force is one of the four fundamental forces of nature and is significant in radioactivity – the spontaneous emission of energy and/or subatomic particles i.e. an unstable nucleus will decompose spontaneously (decay) into a more stable configuration. Note, this is done by emitting specific particles and/or specific amounts/forms of energy. For example, radioactive beta decay transforms a neutron into a proton, an electron, and an electron anti-neutrino.
The standard model describes these forces in terms of the exchange of virtual force carriers. In this model the weak force is thought to interact thorough the exchange of the massive (~ 100 x mass of a proton)...
The first detection of gravitational waves in 2015 created huge excitement because it confirmed a long-standing prediction of Albert Einstein’s general theory of relativity and opened up a completely new way of observing the universe. Physicists have also been scrutinizing data from the growing number of gravitational-wave detections for “echoes” – the existence of which could mean that our understanding of relativity is incomplete. Physicists in Canada and Iran have found tentative evidence for such echoes gravitational waves from colliding black holes, and now say a stronger signal exists in data from colliding neutron stars.
“So far everyone who has looked for echoes has found them, including the LIGO group.”
—Niayesh Afshordi of the University of Waterloo and the Perimeter Institute for Theoretical Physics.
Many physicists believe that general relativity is incomplete...
The biggest map of our galaxy just got revealed and it confirms the intriguing discrepancy in the value of the Hubble constant, further questioning our understanding of the expanding Universe.
Hubble’s constant – which is essentially a measure of the speed of the expanding universe – is determined by two different methods. One method looks at the early universe through the observation of the Cosmic Microwave Background (CMB) and the other method looks at the local universe through the light emitted by Cepheid variables.
In a recent news post, we described how Nobel laureate Adam Reiss and his team at the Space Telescope Science Institute determined a value for the Hubble constant 9% higher than that found by the CMB method. This value was found to an improved accuracy compared to previous studies and thus brings into question the reason for such a discrepancy.
Now with the help of Gaia, the...
As Reported by Syl Kacapyr at Cornell University:
While defects in a diamond are mostly undesirable, certain defects are a quantum physicist’s best friend, having the potential to store bits of information that could one day be used in a quantum computing system.
Applied physicists at Cornell have demonstrated a technique for engineering some of the key optical properties of those defects, providing a new tool for exploring quantum mechanics.
A group of researchers led by Greg Fuchs, professor of applied and engineering physics, have become the first to use vibrations produced by a resonator to help stabilize those optical properties, forcing the diamond’s electrons into an excited orbital state. The research is detailed in the paper “Orbital State Manipulation of a Diamond Nitrogen-Vacancy Center Using a Mechanical Resonator,” published April 17 in the journal Physical Review Letters.
Much like a computer’s transistors record binary information by...
Metamaterials researchers at Duke University have demonstrated the design and construction of a thin material that can control the redirection and reflection of sound waves with almost perfect efficiency.
While many theoretical approaches to engineer such a device have been proposed, they have struggled to simultaneously control both the transmission and reflection of sound in exactly the desired manner, and none have been experimentally demonstrated.
The new design is the first to demonstrate complete, near-perfect control of sound waves and is quickly and easily fabricated using 3-D printers. The results appear online April 9 in Nature Communications.
"Controlling the transmission and reflection of sound waves this way was a theoretical concept that did not have a path to implementation—nobody knew how to design a practical structure using these ideas," said Steve Cummer, professor of electrical and computer...
The properties of water have fascinated scientists for...
The mystery behind how birds navigate might finally be solved: it's not the iron in their beaks providing a magnetic compass, but a newly discovered protein in their eyes that lets them "see" Earth's magnetic fields.
These findings come courtesy of two new papers - one studying robins, the other zebra finches.
The fancy eye protein is called Cry4, and it's part of a class of proteins called cryptochromes - photoreceptors sensitive to blue light, found in both plants and animals. These proteins play a role in regulating circadian rhythms.
There's also been evidence in recent years that, in birds, the cryptochromes in their eyes are responsible for their ability to orient themselves by detecting magnetic fields, a sense called magnetoreception.
Galaxies and dark matter go hand in hand; you typically don't find one without the other. So when researchers uncovered a galaxy, known as NGC1052-DF2, that is almost completely devoid of the stuff, they were shocked.
"Finding a galaxy without dark matter is unexpected because this invisible, mysterious substance is the most dominant aspect of any galaxy," said lead author Pieter van Dokkum of Yale University. "For decades, we thought that galaxies start their lives as blobs of dark matter. After that everything else happens: gas falls into the dark matter halos, the gas turns into stars, they slowly build up, then you end up with galaxies like the Milky Way. NGC1052-DF2 challenges the standard ideas of how we think galaxies form."
The research, published in the March 29th issue of the journal Nature, amassed data from the Gemini North and W. M. Keck Observatories, both on Maunakea, Hawai'i, the Hubble...
The accuracy of the Hubble constant has been a topic of debate since its discovery in the 1920’s. When an agreement seemed to be finally on the horizon a new measuring technique showed a discrepancy and now that discrepancy has just been verified to even more accuracy.
The Hubble constant was discovered by Edwin Hubble in 1929 through his observational studies of the recession velocities of galaxies. Hubble found that the recession velocity of galaxies increased with increasing distance at a proportional rate, now known as the Hubble constant.
The Hubble constant has since been measured with varying degrees of accuracy from 500km/s/Mpc to 100 km/s/Mpc until finally agreeing on ~70 km/s/Mpc. However, the alternative method for measuring the Hubble constant – from the cosmic microwave background (CMB) – yields a slightly lower number. This discrepancy has now been confirmed with even greater accuracy by Nobel...
When something seems a little mysterious or we just don’t understand what is going on we like to describe it with the adjective ‘dark’.
This is one of the reasons why the term ‘dark’ matter got coined which was first proposed to explain the anomaly observed in the rotational velocities of galaxies. That is – the observed rotational velocities of the gas and dust at the outer edges of a galaxy is rotating just as fast as the gas and dust near its center. This anomaly was first noted in 1978 by Vera Rubin and W. Kent Ford who made precise measurements utilizing a new instrument that Ford himself had designed. At first, they thought their data could be erroneous, but then their results were corroborated by subsequent observations of galactic rotational velocities, suggesting that there was indeed an anomaly between what is expected and what was observed!