Yesterday I posed a question - Are the first collisions recorded by the LHC running at 13 TeV the highest-energy ever produced by mankind with subatomic particles ? It was a tricky one, as usual, meant to think about the matter.

I received several tentative answer in the comments thread, and thus answered there. I paste the text here as it is of some interest to some of you and I wish it does not go overlooked.


Dear all, 
The LHC has finally started to produce 13-TeV proton-proton collisions!

The picture below shows one such collision, as recorded by the CMS experiment today. The blue boxes show the energy recorded in the calorimeter, which measures particle energy by "destroying" them as they interact with the dense layers of matter that this device is made up of; the yellow curves show tracks reconstructed by the ionization deposits of charged particles left in the silicon detector layers of the inner tracker. 
A new simulation that explains the collision between clusters of galaxies known as "El Gordo" also challenges popular thinking on the blanket term for undetected 'dark matter'.

In general, galaxy clusters grow in size by merging with each other due to gravitations forces despite the expansion of the universe. El Gordo is the biggest known cluster of galaxies, and is in turn the result of the collision between two large clusters. The simulation believes that the collision process compresses the gas within each cluster to very high temperatures so that it is shining in the X-ray region of the spectrum. In the X-ray spectrum this gas cloud is comet shaped with two long tails stretching between the dense cores of the two clusters of galaxies.
Burton Richter, 1975 Nobel prize in Physics for the discovery of the J/ψ meson, speaks about the need of a new linear collider for the measurement of Higgs boson branching fractions in a video on Facebook (as soon as I understand how to paste here I will!)

Richter has been a fervent advocate of electron-positron machines over hadronic accelerators throughout his life. So you really could not expect anything different from him - but he still does it with all his might. At one point he says, talking of the hadron collider scientists who discovered the Higgs boson:

I am very happy today because I have been notified by the European Community that a project I submitted for funding as coordinator last January has been evaluated very positively by the EU reviewers. The project is a training network of universities and research centres in Europe, with participation of two additional academic partners and four industrial partners from the US, Russia, Italy and Belgium. The network name is "AMVA4NewPhysics", and it aims at developing and applying cutting-edge statistical learning tools to new physics and Englert-Higgs boson studies to the LHC data collected by ATLAS and CMS.

Rydberg atoms, atoms whose outermost electrons are highly excited but not ionized, might be just the thing for processing quantum information. These outsized atoms can be sustained for a long time in a quantum superposition condition (a good thing for creating qubits) and they can interact strongly with other such atoms, making them useful for devising the kind of logic gates needed to process information. 

There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.

Richard Feynman, who would turn 97 years old today. Happy birthday, mr. Feynman!

All light is made of electromagnetic waves.  This means that like any wave, there is something repeatedly sloshing back and forth with light.  A water wave is crests and troughs on the water going up and down over and over as they travel across the surface.  Light waves have some resemblance in that with light, it is electric and magnetic fields which are periodically wobbling back and forth. 

When a mirror reflects light, it experiences a slight push but it is negligible in our everyday lives. Our furniture is not moving because due to radiation pressure of light, a 100 Watt light-bulb causes a radiation pressure that is only a trillionth (one part to 1000000000000) of the normal atmospheric pressure.