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The title says it all: this blog features physics videos found everywhere on the web: animations, demonstrations, lectures, documentaries.
Please go here if you want to suggest other nice physics videos, and here if I mistakingly infringed your copyrights. If you understand French, you'll find a huge selection of physics videos in French in my other blog Vidéos de Physique.
Showing posts with label Quantum chromodynamics. Show all posts
Showing posts with label Quantum chromodynamics. Show all posts

Wednesday, 19 June 2013

The Vacuum is NOT Empty

An atom is mostly empty space, but empty space is mostly not empty. The reason it looks empty is because electrons and photons don't interact with the stuff that is there, quark and gluon field fluctuations.

It actually takes energy to clear out space and make a true 'empty' vacuum. This seems incredibly counter-intuitive but we can make an analogy to a permanent magnet. When at low energies, like at room temperature, there is a magnetic field around the magnet due to the alignment of all the magnetic moments of the atoms. But if you add some energy to it by heating it, the particles gain thermal energy, which above the Curie temperature makes their magnetic moments randomly oriented and hence destroying the magnetic field. So in this case energy is needed to clear out the field, just as in the quantum vacuum.

 Special thanks to Professor Derek Leinweber, find out more about his research here.

 

Wednesday, 15 May 2013

Your Mass is NOT from Higgs Boson

The Higgs mechanism is meant to account for the mass of everything, right? Well no, only the fundamental particles, which means that electrons derive their mass entirely from the Higgs interaction but protons and neutrons, made of quarks, do not. In fact the quark masses are so small that they only make up about 1% of the mass of the proton (and a similar fraction of the neutron). The rest of the mass comes from the energy in the gluon field. Gluons are massless, but there is so much energy in the field that by E=mc^2 there is a significant amount of mass there. This is where most of your mass comes from and the mass of virtually everything around you.