Cassini Watches Mysterious Feature Evolve in Titan Sea

These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. Image Credit: NASA/JPL-Caltech/ASI/Cornell

These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn’s moon Titan. Image Credit: NASA/JPL-Caltech/ASI/Cornell

NASA’s Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn’s moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini’s radar experiment, but its appearance changed between the two apparitions….
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Electron Handedness Affects Gas Molecule Breakup

Experiments show that beams of left- or right-handed electrons are not equal-opportunity destroyers of molecules having two mirror-image forms, which supports the idea that primordial cosmic rays generated the asymmetry in biological molecules.

An asymmetric reaction billions of years ago between electrons and the ancestors of biomolecules might explain why today’s DNA always appears as a right-handed helix. Now researchers have shown that a beam of right-handed electrons—whose spin and direction of motion align according to the right hand—breaks apart more right-handed molecules at low energies than left-handed ones. Unlike previous experiments showing such a difference, the reactions occurred in the gas phase and with low-energy electrons, which allowed for a more precise description of the electron-molecule interactions. The researchers say their results are an important step toward more direct tests of the hypothesis that nuclear asymmetries led to asymmetries in present-day biomolecules.

Many molecules come in both left- and right-handed (chiral) forms, but natural DNA is always right-handed. The asymmetry “is one of the few unsolved fundamental questions in [the] natural sciences,” says Uwe Meierhenrich, a physical chemist at the University of Nice Sophia Antipolis in France.

One possible explanation comes from nuclear physics. The radioactive decay of a nucleus is more likely to produce a left-handed electron than a right-handed one—meaning that it’s more likely to spin in the direction of your left hand’s curled fingers when you point your left thumb in the direction of its motion. When this asymmetry was discovered in 1957, “it showed us that God is not ambidextrous,” says Timothy Gay of the University of Nebraska in Lincoln. Continue reading Electron Handedness Affects Gas Molecule Breakup


Unconventional Superconductivity

Crystal structure of the cuprate Bi2212

Crystal structure of the cuprate Bi2212

M. R. Norman
A brief review of unconventional superconductivity is given, stretching from the halcyon days of helium-3 to the modern world of Majorana fermions. Along the way, we will encounter such strange beasts as heavy fermion superconductors, cuprates, and their iron-based cousins. Emphasis will be put on the fact that in almost all cases, an accepted microscopic theory has yet to emerge. This is attributed to the difficulty of constructing a theory of superconductivity outside the Migdal-Eliashberg framework…
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The Apollo Missions And The Hunt for Gravitational Waves

Apollo astronauts left an array of seismometers to study moonquakes. Now astrophysicists are scouring the data for evidence of gravitational waves

apollo111One of the great unanswered questions in science is whether the universe is filled with gravitational waves and if so, whether we can spot them. This question comes directly from Einstein’s theory of general relativity which assumes that the fabric of the cosmos is able to warp, bend and vibrate like a rubber sheet.

The bending and warping effectively causes gravity, the effects of which we can measure in detail. The vibrating is gravitational waves but physicists have yet to see this directly. However, they are hugely confident that gravitational waves must permeate the universe and have spent hundreds of millions of dollars building machines to spot them, so far unsuccessfully.

in recent years, a number of scientists have begun to point out that there may be much cheaper ways of finding gravitational waves. One idea is to study pulsars since the precise signals they send out must “shimmer” when gravitational waves pass by.

Another idea is to look at the Earth itself. The thinking is that it must vibrate like a bell when gravitational waves pass by. So there could be signs of this vibration in the data collected by the global network of sensors set up to measure seismic vibrations around the planet…..
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