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Archivio digitale delle tesi discusse presso l’Università di Pisa

Tesi etd-04012021-213337


Tipo di tesi
Tesi di laurea magistrale
Autore
CAMA, ERLIN
URN
etd-04012021-213337
Titolo
ENERGIA NUCLEARE & BUCHI NERI
Dipartimento
SCIENZE POLITICHE
Corso di studi
SCIENZE MARITTIME E NAVALI
Relatori
relatore Dott. Diana, Luigi
Parole chiave
  • Black holes
  • Nuclear Energy
Data inizio appello
10/04/2021
Consultabilità
Tesi non consultabile
Riassunto
Black holes are defined as objects where the geometry of space-time is deformed in such a drastic way that the entire region is invisible to an outside observer. Hawking proposed that the horizon ofthe black hole should emit thermal radiation, a term coined as Hawking’s radiation. The temperature and luminosity of the radiation are inversely proportional to the black hole mass, MBH. The predicted Hawking temperature of a black hole with a mass equivalent of 30 solar mass is about 2 x 10-9K and its luminosity about 10-31 Watts. The measurements from a quantum simulator of a black hole shows the quantum regime from the population distribution of 1.2 x 10-9 K far below the measured and predicted 2 x 10-9K upper limit for quantum entanglement.
Frist concept of presence of black hole dates back in 1783. John Mitchell send a paper to Lord Henry Cavendish of Royal Society, predicting the existence of “dark stars”. Mitchell predicted that a star as dense as the sun but about 500 times as wide in diameter will apply a gravitational pull that even the light will not be able to escape. Even light will not be able to escape the gravitational pull of such massive and dense star. As a result, one would not be able to observe such stars. Mitchell gave an elegant explanation: “…yet, if any other luminous bodies should happen to revolve about them, we might still perhaps from the motion of these revolving bodies infer the existence of the central ones with some degree of probability, as this might afford a clue to some of the apparent irregularities of the revolving bodies, which would not be easily explicable on any other hypothesis”. Independently, the president of the institute de France, Pierre-Simon Laplace developed this idea of dark stars and predicted what astronomers now know to be true: “ The largest luminous bodies in the universe may thus be invisible by the reason of their magnitude”.
Both these scientists were in agreement about the existence of the object in question, they were pretty far off in predicting its form. Huygen’s wave theory of light was gaining popularity around the beginning of 19 century, especially after Young’s double slit experiment (1803) and Fresnel’s work on the diffraction of light (1818). The wave nature of the light made it difficult for Newtonian gravity to explain the effect of a star’s gravity on the light it emits and it became much more problem to solve. For this reason, Laplace omitted the idea of dark stars from the 3rd edition of Exposition.
As Tesla was making contributions with his design of the modern alternating current supply, science had not made too much of progress on the Newton first fundamental force, the initial concept that started it all. Newton theory of gravity was able to predict most terrestrial motion, but it could not explain perturbations in Mercury’s orbit, the bending of light in gravitational fields, and the gravitational redshift. According to Newton theory relied on the notion that time is absolute. A more satisfactory answer was provided in the early years of 20th century.
In 1905, Albert Einstein a 26 year old German patent clerk presented his theory of special relativity, which de-seated Newton’s classical mechanics. Einstein suggested that there was no such thing as absolute time. His two major ideas were that laws of physics will appear the same to any observer who is at rest or not accelerating, and the speed of light in vacuum is the same regardless of the reference point. Such speed is the maximum of anything that can be achieved in our physical world. In 1916, Einstein completed his general relativity by suggesting to look at space and time geometrically. If one imagines space-time as a sort of fabric, then gravity is simply the result of smaller bodies being pulled by the dent in the fabric caused by massive bodies?
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