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Aristotle added a fifth element, aether (αἰθήρ aither), as the quintessence, reasoning that whereas fire, earth, air, and water were earthly and corruptible, since no changes had been perceived in the heavenly regions, the stars cannot be made out of any of the four elements but must be made of a different, unchangeable, heavenly ...
Following Anaximander, his pupil Anaximenes (c. 585 – c. 528/4) held that the stars, Sun, Moon, and planets are all made of fire. But whilst the stars are fastened on a revolving crystal sphere like nails or studs, the Sun, Moon, and planets, and also the Earth, all just ride on air like leaves because of their breadth. [9]
Although the Sun is a star, its photosphere has a low enough temperature of 6,000 K (5,730 °C; 10,340 °F), and therefore molecules can form. Water has been found on the Sun, and there is evidence of H 2 in white dwarf stellar atmospheres. [2] [4] Cooler stars include absorption band spectra that are
A star is a luminous spheroid of plasma held together by self-gravity. [1] The nearest star to Earth is the Sun.Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light.
The innermost spheres are the terrestrial spheres, while the outer are made of aether and contain the celestial bodies. In Plato's Timaeus (58d) speaking about air, Plato mentions that "there is the most translucent kind which is called by the name of aether (αἰθήρ)" [9] but otherwise he adopted the classical system of four elements.
Astrophysical plasmas are also observed in accretion disks around stars or compact objects like white dwarfs, neutron stars, or black holes in close binary star systems. [45] Plasma is associated with ejection of material in astrophysical jets , which have been observed with accreting black holes [ 46 ] or in active galaxies like M87's jet that ...
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Ch.3 Composition of the four elements; air, earth, fire, and water. Topics also include the composition of the space between earth and stars, the double nature of exhalation, and the composition of clouds. This chapter also contains Anaxagoras' analysis of the element ether Ch.4 Shooting Stars Ch.5 The Aurora Borealis and its affects