We are on. This afternoon just after 1PM the LHC beams have started to produce proton-proton collisions in the heart of the experiments, at the never-before achieved energy of 7 TeV.
It was a long journey to get here -the project is twenty years old- but this is just the start of a new, more exciting one: In the course of the next two years, the Large Hadron Collider will gradually increase its power, allowing the CMS and ATLAS detectors to collect enough data to significantly extend into discovery territory.
So how dangerous is the Large Hadron Collider? How likely is it that when operated at maximum energy the LHC will create a black hole and wipe out earth? Eric Johnson, assistant professor of law at the University of North Dakota and author of the report The Black Hole Case: The Injunction Against The End Of The World, writes in a recent edition of New Scientist:
Scientists have discovered the world's smallest superconductor, a sheet of four pairs of (BETS)2GaCl4 molecules less than one nanometer wide.
Their new Nature Nanotechnology study provides the first evidence that nanoscale molecular superconducting wires can be fabricated, which could be used for nanoscale electronic devices and energy applications.
The "exceptionally simple theory of everything," proposed by physicist Antony Garrett Lisi in 2007 does not hold water, according to a particle physicist and mathematician writing in Communications in Mathematical Physics.
In November of 2007, Lisi published an online paper entitled "An Exceptionally Simple Theory of Everything." The paper centered on the elegant mathematical structure known as E8, which also appears in string theory. First identified in 1887, E8 has 248 dimensions and cannot be seen, or even drawn, in its complete form.
Two and a half months since Erik Verlinde submitted his entropic gravity paper, and all of physics and cosmology has turned into entropy. Well, I am exaggerating a bit, and perhaps more than just a bit. Yet, fact is that within two weeks of Erik's publication a steady stream of 'entropic everything' papers has developed at a rate of close to one paper per day. Gravity, Einstein's equations, cosmic expansion, dark energy, primordial inflation, dark mass: it's all entropic. Chaos rules.
Quantum mechanics has been around for a hundred years and continues to fascinate and astonish scientists. It has been phenomenally successful at explaining the microscopic universe at the level of atoms and elementary particles and yet classical mechanics has survived to model the macroscopic world of everyday objects. But at what level do these two theories meet? Is there a region in which they could overlap; that is, can macroscopic objects display quantum behaviour?
The number in the title, interpreted in units per square centimeters per second, is a flux rate, and it is a new world record set by the Tevatron collider last night on the number of protons and antiprotons forced to cross each other within a tiny interaction region in the core of the CDF and DZERO experiments.
By changing the material medium through which x-rays pass, physicists at Lawrence Berkeley National Laboratory have used laser light to control x-ray beams.
As a new generation of powerful light sources comes online, intense x-ray beams may be able to control matter directly and allow one beam of x-rays to control another, the new Nature Physics study suggests.
Using the Lawrence Berkeley National Laboratory's Advanced Light Source femtosecond spectroscopy beamline 6.0.2, researchers sent ultrashort pulses of laser light and higher-frequency x-rays together through a gas cell filled with pressurized neon. Excited by the laser pulses, the gas, which normally absorbs x-rays, became transparent to the x-ray pulses during their quick passage.
It makes me very happy when I see new precise results on the mass of the top quark being produced by the CDF collaboration (to which I still proudly belong). CDF, one of the two hadron collider experiments operating at the 2-TeV Tevatron proton-antiproton synchrotron in Batavia, IL, has been measuring the top quark mass since 1994, one year prior to its discovery. The figure with the top candidates (histogram) from which the mass measurement of 174+-12 GeV was obtained in 1994 is shown on the right below; backgrounds and top expectation are shown by hatched lines.