Athen vs Sun

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Athens ( ATH-inz; Greek: Αθήνα, romanized: Athína [aˈθina] (listen); Ancient Greek: Ἀθῆναι, romanized: Athênai (pl.) [atʰɛ̂ːnai̯]) is the capital and largest city of Greece. Athens dominates the Attica area and is one of the world's oldest cities, with its history spanning over 3,400 decades and its earliest human presence started somewhere between the 11th and 7th century BC.Classical Athens was a strong city-state. A centre for the arts, learning and philosophy, home of Plato's Academy and Aristotle's Lyceum, it is widely referred to as the cradle of Western civilization and the birthplace of democracy, largely due to its cultural and political effect on the European continent, and particularly the Romans. These days, Athens is a large cosmopolitan metropolis and central to economic, financial, industrial, marine, cultural and political life in Greece. Athens is a Beta worldwide city based on the Globalization and World Cities Research Network, and is one of the biggest economic centers in southeastern Europe. It has a large financial industry, and its port Piraeus is both the largest passenger port in Europe, and the second largest in the world.The Municipality of Athens (also City of Athens), which really constitutes a tiny administrative unit of the entire city, had a population of 664,046 (in 2011) within its official limits, and a land area of 38.96 km2 (15.04 sq mi). The Athens Urban Area (Greater Athens and Greater Piraeus) extends beyond its administrative municipal city limits, with a population of 3,090,508 (in 2011) within an area of 412 km2 (159 sq mi). According to Eurostat in 2011, the functional urban area (FUA) of Athens was the 9th most populous FUA in the European Union (the 6th most populous capital city of the EU), with a population of 3.

8 million people. Athens is also the southernmost capital on the European mainland and the warmest major city in Europe. The heritage of the classical era is still evident in the city, represented by ancient monuments and works of art, the most famous of all being the Parthenon, considered a key landmark of ancient Western civilization. The town also retains Roman and Byzantine monuments, in addition to a smaller number of Ottoman monuments, while its historical urban center features elements of continuity through its millennia of history. Athens is home to two UNESCO World Heritage Sites, the Acropolis of Athens and the medieval Daphni Monastery. Landmarks of the modern age, dating back to the establishment of Athens as the capital of the independent Greek state in 1834, include the Hellenic Parliament and the so-called"architectural trilogy of Athens", comprising the National Library of Greece, the National and Kapodistrian University of Athens and the Academy of Athens. Athens is also home to several museums and cultural institutions, like the National Archeological Museum, featuring the world's largest collection of ancient Greek antiquities, the Acropolis Museum, the Museum of Cycladic Art, the Benaki Museum and the Byzantine and Christian Museum. Athens was the host city of the first modern-day Olympic Games in 1896, and 108 decades after it hosted the 2004 Summer Olympics, which makes it one of the few cities to have hosted the Olympics more than once.

Source: Wikipedia

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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