If one refers to capsules Nos. 1 & 2 of 9 and 22 August, so we know now that the atom, however small it is not the smallest particle known. It includes a core surrounded by electrons that extremely small pirouette around the nucleus and are indivisible (can not be cut).
For its part, the core is composed of protons and neutrons are themselves agglomerates of quarks. It often represents the atom like this, although this is a fictitious image because we never saw the atom :
In this illustration of the atom, the balls red and blue Rep resentencing the nucleus composed of protons (red balls) and neutrons (blue marbles). Electrons are the black balls.
All matter known is made of atoms: your computer table, the little flower that you've put your cat that comes to graze on your leg, the sun whose rays enter through your window, the stars enchant your nights, you , me, everything is atoms.
But what is surprising is that atoms are made of mostly empty. If, to quote a friend of mine recently physicists, we represented the nucleus of the atom as the point of a needle, the size of the atom correspond to the volume of room you're sitting at your computer. So a core size of a needle (which, incidentally, contains 99.98% of the mass of the atom) lost in the vastness of a room and everything else is a void crisscrossed by tiny electrons ( which represent only 0.02% of the mass of the atom, both say almost nothing). Bizarre is not it, to think that we are made mostly of empty! ( I hear you mutter that, in my case, it does not surprise you ) .
Even more surprising is the fact that lo IS normal physical, those particularly set out by the great Isaac Newton and govern our daily behavior (as, for example, the law of universal gravitation keeps you feet glued to the ground and can interpret both falling bodies that the movement of Moon around the Earth ) become negligible if not impracticable in the world of the very small. In this world, there are other laws that take center stage: the laws of what is called quantum mechanics . This mechanism describes the behavior of atoms and particles composing them.
A ith the theory of relativity, Einstein, quantum mechanics has been the most revolutionary scientific theory of the twentieth century. It enables us to access the world of extremely small people of atoms, photons, neutrinos, quarks and other particles with exotic names. It's a weird and confusing world that seems to defy logic and common sense. However, quantum theory has proven since it is the source of great technological advances of our time: electronics, its transistors, its semi-conductor, laser, etc..
Until the 1920s, was believed to know the nature of matter and be able to gradually penetrate the secrets of the universe. We took for granted that if we knew all the ingredients of a problem, we could solve it. The world was now no mystery and little by little, we happen to explain everything.
Chance had no place in this universe where the spokes deterministic we reigned supreme. But now that quantum mechanics just throw a stone into this pond of certainty at the extremely small, the world is more orderly, deterministic, as in our daily lives. It becomes uncertain and random. The scientific world is going under.
This mechanism opens our eyes to strange mysteries, particularly the fact that we can not accurately predict the behavior of particles but it must be content with probabilities.
Let me explain : if I sit on the curb and I watch a car pass me, I obviously can locate exactly where this car and if I have a radar in hand, I can simultaneously know exactly sure ent speed. Well, in the quantum world, nothing goes: if I can locate an electron, I'm no longer capable of simultaneously establishing its speed.
Conversely, if I set the speed, I do not know more accurately where the secretive electron. I must be content to be approximately. This is what Heisenberg called the uncertainty principle. " Sacrilege that has shaken the foundations of classical physics where you swore on the altar of certitude.
You know nothing at this quantum mechanics? Well, you're on the right track: there is nothing to understand. " I think I can say without much fear of contradiction that no one understands quantum mechanics " said the gra nd physicist Richard Feynman.
But there are even stranger in this world of extremely small: the particles that are born of nothing and disappear in a flash, in the words of Pierre Yves Morvan :
" ... for a very short time, the principle of conservation of energy can be violated. This principle says that in fact has something for nothing, that everything is paid, or you can not have both the cake and eat it too. This has already told them how Empedocles and Lavoisier: "Nothing is lost, nothing is created .
Yet Heisenberg relations that allow pairs particle-antiparticle appear from nothing and exist for some time.
This means that particles arise from a quantum wand and come without any invitation to the grand ball to be. "
Then it is unable to calculate when a neutron disappears: his death is left to chance. Lavoisier turned in his grave.
Einstein fought all his life quantum physics vainem ent. He could not admit that, at the infinitesimal, the behavior of particles is left to chance. Hence, his famous words: "God does not play dice." To which his opponent, yet friend, Niels Bohr replied "Who are you, Einstein to tell God what to do?"
other hand, no one knows what really matter. If, for example, we examine the electron leaves a trace on a metal plate, a particle is detected. If he turns his back, he behaves like a wave. Some even argue a "string theory" in which the atom is not a particle but is due to vibrations?? Who is he really? I like to recall in this connection the words of a strophysicien James Dean saying that the universe looks like sometimes more a great thought than a great machine.
we can say that, at the extremely small, reality escapes us. The world of the deterministic, which was moving towards a world without mystery, suddenly becomes a murky world where ghosts prevail.
Boo!
0 comments:
Post a Comment