Records have been broken. Pulverized, even. A mainly European collaboration has just observed, in the Mediterranean Sea, the most 'ultra-high energy' elementary particle, as detailed in Nature on Wednesday, February 12. Twenty thousand times more energetic than in the most powerful particle collider, the LHC, at the European Centre for Nuclear Research. Thirty times more than the previous record. The only particles more agitated than this one are cosmic rays, which are puffs of protons and therefore non-elementary, and which can reach an energy a thousand times greater.

In the language of physicists, the record is equivalent to 220 peta-electronvolts (PeV), or 220 billion million electronvolts. An electronvolt is the energy of an electron accelerated by a voltage of just one volt. And 220 PeV is equivalent to the kinetic energy of a ping-pong ball dropped from one meter... Ridiculous? Not exactly, because we're talking about a particle billions of billions of times smaller than those white balls.

Which particle is captivating all this attention? One of the most fascinating: the neutrino. As its name suggests, this family of particles, the second most abundant in the Universe, carries no electrical charge. The neutrino is also almost massless and travels at almost the speed of light. And it interacts very weakly with matter. One hundred billion of them pass through every square centimeter of our skin every second from the Sun, unhindered. Once created, they travel in a straight line without being deflected from their trajectory by magnetic fields or other particles, and without stopping. So much so that some people dream of one day observing those emitted just after the Big Bang.

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