Big Bang and stellar Oggi, Capodanno, mi viene da pensare , chissà poi perchè, all'Universo. E ne vorrei parlare, per quanto ne so, ma in termini scientifici, evitando le connessioni che, inevitabilmente, potremmo fare con la Filosofia e la Religione.
Si intende per Universo l'insieme della materia e dell'energia presenti, intercorrelati secondo la ben nota formula di A. Einstein ( 1905))
E = M c2 
(immagine tratta dal web)
Tre sono, in sostanza, i modelli proposti per l'Universo:
Universo chiuso secondo cui, dopo la nascita e la temporanea evoluzione, si avrebbe un periodo di involuzione dell'insieme spazio-temporale, fino a collassare (implodere) verso un punto di concentrazione massima della materia ( ritorno all'origine, o
Big Crunch )
Universo piatto o stazionario , secondo cui l'evoluzione dell'Universo tende asintoticamente verso un valore (y) e tale permarrebbe nel tempo
Universo aperto , secondo cui il cosmo ha un processo espansivo continuo e crescente nel tempo.
Numerosi fisici hanno lavorato intorno all'idea degli Universi; vorrei ricordare Friedman (anni trenta del 1900) , secondo cui l'evoluzione dell'Universo dipende dalla densità media della materia in esso contenuta; se la densità della materia fosse maggiore di un critical value (estimated at 5 X 10-30 g/cm3, the expansion would stop and would contract, making collasssare the whole universe (Big Crunch), the theory assumes that an explosion might occur, and then expand and collapse in an infinite loop:
button or oscillating universe .
In 1948 Gamow wrote the Big Bang theory of cosmic (or standard cosmological model, as it should be called) that the start would have been compressed matter in quark, after a few fractions of a second, the quarks would be broken down into protons, neutrons and hadrons, after about three minutes, protons and neutrons would rise to the simplest elements and light hydrogen, helium, lithium. The training of other elements would be followed over time.
To date, no one knows if the universe is open, closed or stationary: measuring the masses of the various galaxies, physicists presuppose the existence of dark matter
, that is, invisible matter, which gravitate inside of Galaxies .
The very attempt to better understand the supposed Big Bang and phenomena that would follow, led to the formulation of the theory of inflation (the eighties), introducing concepts from the physics of elementary particles.
If there was a big explosion, came a dense agglomeration of radiation and matter, held together by a very strong force, the union of the four known forces of nature. Col
cooling, radiation and particles would be separated, and the same would happen to the four forces: the material has prevailed on anti-matter, quarks together to form atomic nuclei and the Universe would become 'transparent'.
Mystery permeates these first moments of universal life: the physics is confused at times with the philosophy and religion (there is a primum
movens ,
the 'love that moves the world and other things , according to Dante ?
I think these arguments are bellissimi.Pensate: not only would the union of the original matter and energy early on, actually think, even what we now call
the various disciplines (physics, mathematics, philosophy, biology-elect), would have been merged into a single point, POINT .
Well, stuff to put the chills.
Hello everyone and greetings stellar
