A Force From Empty Space: The Casimir Effect

A Force From Empty Space: The Casimir Effect

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This tiny ball provides evidence that the universe will expand forever.

Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space. The attraction is known as the Casimir Effect, named for its discoverer, who, 55 years ago, was trying to understand why fluids like mayonnaise move so slowly.

Today, evidence indicates that most of the energy density in the universe is in an unknown form dubbed dark energy. The form and genesis of dark energy is almost completely unknown, but postulated as related to vacuum fluctuations similar to the Casimir Effect but generated somehow by space itself.

This vast and mysterious dark energy appears to gravitationally repel all matter and hence will likely cause the universe to expand forever. Understanding vacuum energy is on the forefront of research not only to better understand our universe but also for stopping micro-mechanical machine parts from sticking together.

Image Credit & Copyright: Umar Mohideen (U. California at Riverside)
Source: APOD

China Is Building The World Largest Particle Collider

China Is Building The World Largest Particle Collider

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Rendering of the proposed CEPC. Image credit: IHEP

China is planning to build the world largest Particle Collider in 2020,​ twice the size of CERN’s Large Hadron Collider.

The subterranean facility of the Chinese Particle Collider will be at least twice the size of the Large Hadron Collider (LHC) in Switzerland.

The supercollider will endeavor to find out more about the mysterious Higgs boson.

Wang Yifang, director of the Institute of High Energy Physics, Chinese Academy of Sciences, told China Daily:

“We have completed the initial conceptual design and organized international peer review recently, and the final conceptual design will be completed by the end of 2016.

The LHC is hitting its limits of energy level. While the LHC smashes together protons, it generates Higgs particles together with many other particles. The proposed CEPC, however, collides electrons and positrons to create an extremely clean environment that only produces Higgs boson particles.”

Source: Chinese Academy of Sciences
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LHC Re-creates First Moments Of The Universe

LHC Re-creates First Moments Of The Universe

Lead ions collide in the CMS detector (Image: CMS)

Lead ions collide in the CMS detector (Image: CMS)

After the successful restart of the Large Hadron Collider (LHC) and its first months of data taking with proton collisions at a new energy frontier, the LHC is moving to a new phase, with the first lead-ion collisions of season 2 at an energy about twice as high as that of any previous collider experiment.

Following a period of intense activity to re-configure the LHC and its chain of accelerators for heavy-ion beams, CERN’s accelerator specialists put the beams into collision for the first time in the early morning of 17 November 2015 and ‘stable beams’ were declared at 10.59am today, marking the start of a one-month run with positively charged lead ions: lead atoms stripped of electrons.

The four large LHC experiments will all take data over this campaign, including LHCb, which will record this kind of collision for the first time. Colliding lead ions allows the LHC experiments to study a state of matter that existed shortly after the big bang, reaching a temperature of several trillion degrees.

Lead ions collide in the ALICE detector (Image: ALICE)

Lead ions collide in the ALICE detector (Image: ALICE)

“It is a tradition to collide ions over one month every year as part of our diverse research programme at the LHC,” said CERN Director-General Rolf Heuer. “This year however is special as we reach a new energy and will explore matter at an even earlier stage of our universe.”

Early in the life of our universe, for a few millionths of a second, matter was a very hot and very dense medium – a kind of primordial ‘soup’ of particles, mainly composed of fundamental particles known as quarks and gluons. In today’s cold Universe, the gluons “glue” quarks together into the protons and neutrons that form bulk matter, including us, as well as other kinds of particles.

Lead ions collide in the LHCb detector (Image: LHCb)

Lead ions collide in the LHCb detector (Image: LHCb)

“There are many very dense and very hot questions to be addressed with the ion run for which our experiment was specifically designed and further improved during the shutdown,” said ALICE collaboration spokesperson Paolo Giubellino.

“For instance, we are eager to learn how the increase in energy will affect charmonium production, and to probe heavy flavour and jet quenching with higher statistics. The whole collaboration is enthusiastically preparing for a new journey of discovery.”

Increasing the energy of collisions will increase the volume and the temperature of the quark and gluon plasma, allowing for significant advances in understanding the strongly-interacting medium formed in lead-ion collisions at the LHC. As an example, in season 1 the LHC experiments confirmed the perfect liquid nature of the quark-gluon plasma and the existence of “jet quenching” in ion collisions, a phenomenon in which generated particles lose energy through the quark-gluon plasma. The high abundance of such phenomena will provide the experiments with tools to characterize the behaviour of this quark-gluon plasma. Measurements to higher jet energies will thus allow new and more detailed characterization of this very interesting state of matter.

Lead ions collide in the ATLAS dectector (Image: ATLAS/CERN)

Lead ions collide in the ATLAS dectector (Image: ATLAS/CERN)

“The heavy-ion run will provide a great complement to the proton-proton data we’ve taken this year,” said ATLAS collaboration spokesperson Dave Charlton. “We are looking forward to extending ATLAS’ studies of how energetic objects such as jets and W and Z bosons behave in the quark gluon plasma.”

The LHC detectors were substantially improved during the LHC’s first long shutdown. With higher statistics expected, physicists will be able to look deeper at the tantalising signals observed in season 1.

“Heavy flavour particles will be produced at high rate in Season 2, opening up unprecedented opportunities to study hadronic matter in extreme conditions,” said CMScollaboration spokesperson Tiziano Camporesi. « CMS is ideally suited to trigger on these rare probes and to measure them with high precision. »

For the very first time, the LHCb collaboration will join the club of experiments taking data with ion-ion collisions.

“This is an exciting step into the unknown for LHCb, which has very precise particle identification capabilities. Our detector will enable us to perform measurements that are highly complementary to those of our friends elsewhere around the ring,” said LHCb collaboration spokesperson Guy Wilkinson.

Source: CERN

100 Years of General Relativity

100 Years of General Relativity

From the meeting between Einstein and Chaplin.

From the meeting between Einstein and Chaplin.

100 years ago this month, Albert Einstein redefines General Relativity theory, that remains foundational up to our days.

November marks the 100 anniversary of General relativity, a theory of gravitation developed by Albert Einstein between 1907 and 1915.

According to general relativity, the observed gravitational effect between masses results from their warping of spacetime. If you don’t understand the theory, it’s OK, you are not alone…

Meeting between Chaplin and Einstein:

-“What I admire most about your art” Albert Einstein said, “is its universality. You do not say a word, and yet … the world understands you.”

– It’s true reply Chaplin: “But your fame is even greater… the world admires you, when nobody understands you.”..!!

In this 1919 negative of a solar eclipse, showing light bending around the Sun as predicted in the general relativity, British scientist Sir Arthur Eddington helped verify Einstein’s theory. Credit Wikimedia Commons

In this 1919 negative of a solar eclipse, showing light bending around the Sun as predicted in the general relativity, British scientist Sir Arthur Eddington helped verify Einstein’s theory. Credit Wikimedia Commons

General relativity, also known as the general theory of relativity, is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. General relativity generalizes special relativity and Newton’s law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations.

source wikipedia
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