So how does everyone perceive the Sun to be. Do you believe it's a nuclear reactor and if so, what was the thought on it before nuclear energy was thought about?
* from Wikipedia
The Greek philosopher Anaxagoras, who reasoned that it was a giant flaming ball of metal even larger than the chariot of Helios, and that the Moon reflected the light of the Sun.
In the early years of the modern scientific era, the source of the Sun's energy was a significant puzzle. Lord Kelvin suggested that the Sun was a gradually cooling liquid body that was radiating an internal store of heat.[146] Kelvin and Hermann von Helmholtz then proposed a gravitational contraction mechanism to explain the energy output.
Not until 1904 was a documented solution offered. Ernest Rutherford suggested that the Sun's output could be maintained by an internal source of heat, and suggested radioactive decay as the source.[148] However, it would be Albert Einstein who would provide the essential clue to the source of the Sun's energy output with his mass-energy equivalence relation E = mc2.
In 1920, Sir Arthur Eddington proposed that the pressures and temperatures at the core of the Sun could produce a nuclear fusion reaction that merged hydrogen (protons) into helium nuclei, resulting in a production of energy from the net change in mass.[150] The preponderance of hydrogen in the Sun was confirmed in 1925 by Cecilia Payne using the ionization theory developed by Meghnad Saha, an Indian physicist. The theoretical concept of fusion was developed in the 1930s by the astrophysicists Subrahmanyan Chandrasekhar and Hans Bethe. Hans Bethe calculated the details of the two main energy-producing nuclear reactions that power the Sun.[151][152]
Finally, a seminal paper was published in 1957 by Margaret Burbidge, entitled "Synthesis of the Elements in Stars".[153] The paper demonstrated convincingly that most of the elements in the universe had been synthesized by nuclear reactions inside stars, some like our Sun.
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Me? I 'perceive' the sun to be what science explains it to be. A giant ball of gas and plasma that generates its energy by nuclear fusion of hydrogen nuclei into helium.