The known unknown and the unknown – L’Humanité

Can we encourage high school students to turn to science and its equations by promising them that they will find the delicious emotion of discovery there? Here is an extreme example. May 27, 2021, narrates a recent article ¹international telescope ² It was installed in the desert of Utah (USA) and is designed to detect highly energetic cosmic particles hit by a monster. Almost infinitely small in size (a single subatomic particle or atomic nucleus), and with an energy that at first glance seems trivial (40 joules), but is actually enormous on the particle scale: about 200 exaelectronvolts. The exa electron volt is written as: 10100000000000000000!

For a single particle, the energy is several million times that of the most energetic particle ever made in our most powerful machine, which is 27 kilometers in circumference, at CERN, near Geneva, where the Higgs boson is studied. Such cosmic monsters are rare. The Earth receives approximately 1 per square kilometer per century. They are betrayed by a cascade of secondary particles excited by their sudden arrival in the atmosphere. A waterfall is within reach of a telescope array consisting of 507 stations spread over an area of ​​700 square kilometers.

The article talking about this extremely rare find can be translated with the formula “And they gave their tongue to the cat.” Because astrophysicists admit it: they don’t understand much about it. Where could this monster come from? Was its path through the universe affected by a magnetic field, erasing its original location? How did he gain this amazing energy? What is it made of? They have been transformed into hypotheses.

Scientists are accustomed to naming what they do not know, to color its mystery. There is the known unknown, that which we know exists because it can be deduced from what we already know, but have not yet discovered. And the unknown unknown, the one whose existence we do not even doubt, but the history of science leads us to believe in its possibility. This cosmic monster therefore belongs to the lesser-known part of the unknown. This shows how much of a playground nature provides for young minds.