Sun vs Pavia

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The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as light and infrared radiation. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometres (864,000 miles), or 109 times that of Earth, and its mass is about 330,000 times that of Earth. It accounts for about 99.86% of the total mass of the Solar System. Roughly three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.The Sun is a G-type main-sequence star (G2V) based on its spectral class. As such, it is informally and not completely accurately referred to as a yellow dwarf (its light is closer to white than yellow). It formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core. It is thought that almost all stars form by this process.

In its core the Sun currently fuses about 600 million tons of hydrogen into helium every second, converting 4 million tons of matter into energy every second as a result. This energy, which can take between 10,000 and 170,000 years to escape the core, is the source of the Sun's light and heat. When hydrogen fusion in its core has diminished to the point at which the Sun is no longer in hydrostatic equilibrium, its core will undergo a marked increase in density and temperature while its outer layers expand, eventually transforming the Sun into a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable – but not for about five billion years. After this, it will shed its outer layers and become a dense type of cooling star known as a white dwarf, and no longer produce energy by fusion, but still glow and give off heat from its previous fusion. The enormous effect of the Sun on Earth has been recognized since prehistoric times. The Sun has been regarded by some cultures as a deity. The synodic rotation of Earth and its orbit around the Sun are the basis of solar calendars, one of which is the predominant calendar in use today.

Source: Wikipedia

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Pavia (UK: , US: , Italian: [paˈviːa] (listen), Lombard: [paˈʋiːa]; Latin: Ticinum; Medieval Latin: Papia) is a town and comune of south-western Lombardy in northern Italy, 35 kilometres (22 miles) south of Milan on the lower Ticino river near its confluence with the Po. It has a population of c. 73,086. The city was the capital of the Kingdom of the Lombards from 572 to 774. Pavia is the capital of the fertile province of Pavia, which is known for a variety of agricultural products, including wine, rice, cereals, and dairy products. Although there are a number of industries located in the suburbs, these tend not to disturb the peaceful atmosphere of the town.

It is home to the ancient University of Pavia (founded in 1361), which together with the IUSS (Institute for Advanced Studies of Pavia), Ghislieri College, Borromeo College, Nuovo College, Santa Caterina College, and the Istituto per il Diritto allo Studio (EDiSU), belongs to the Pavia Study System. Pavia is the episcopal seat of the Roman Catholic Bishop of Pavia. The city possesses many artistic and cultural treasures, including several important churches and museums, such as the well-known Certosa di Pavia. The Central Hospital of Pavia is one of the most important hospitals in Italy.

Source: Wikipedia