Sun vs Luanda

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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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Luanda (), is the capital and largest city in Angola. It is Angola's primary port, and its major industrial, cultural and urban centre. Located on Angola's northern Atlantic coast, Luanda is Angola's administrative centre, its chief seaport, and also the capital of the Luanda Province. Luanda and its metropolitan area is the most populous Portuguese-speaking capital city in the world, with over 8.3 million inhabitants in 2020 (a third of Angola's population). Among the oldest colonial cities of Africa, it was founded in January 1576 as São Paulo da Assunção de Loanda by Portuguese explorer Paulo Dias de Novais. The city served as the centre of the slave trade to Brazil before its prohibition. At the start of the Angolan Civil War in 1975, most of the white Portuguese left as refugees, principally for Portugal. Luanda's population increased greatly from refugees fleeing the war, but its infrastructure was inadequate to handle the increase.

This also caused the exacerbation of slums, or musseques, around Luanda. The city is undergoing a major reconstruction, with many large developments taking place that will alter its cityscape significantly. The industries present in the city include the processing of agricultural products, beverage production, textile, cement, newly car assembly plants, construction materials, plastics, metallurgy, cigarettes and shoes. The city is also notable as an economic centre for oil, and a refinery is located in the city. Luanda has been considered one of the most expensive cities in the world for expatriates. The inhabitants of Luanda are mostly members of the ethnic group of the Ambundu, but in recent times there has been an increase of the number of the Bakongo and the Ovimbundu. There exists a European population, consisting mainly of Portuguese. Luanda was the main host city for the matches of the 2010 African Cup of Nations.

Source: Wikipedia