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Sun. The Sun is the star at the center of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies.
The Miracle of the Sun ( Portuguese: Milagre do Sol ), also known as the Miracle of Fátima, is a series of events reported to have occurred miraculously on 13 October 1917, attended by a large crowd who had gathered in Fátima, Portugal in response to a prophecy made by three shepherd children, Lúcia Santos and Francisco and Jacinta Marto.
720,000 km/h (450,000 mi/h) [ 10] Orbital period. ~230 million years [ 10] The Solar System[ d] is the gravitationally bound system of the Sun and the objects that orbit it. [ 11] It was formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc.
The position of the Sun in the sky is a function of both the time and the geographic location of observation on Earth 's surface. As Earth orbits the Sun over the course of a year, the Sun appears to move with respect to the fixed stars on the celestial sphere, along a circular path called the ecliptic . Earth's rotation about its axis causes ...
Contents. Formation and evolution of the Solar System. There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. [ 1 ] Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary ...
Health effects of sunlight exposure. Exposing skin to the ultraviolet radiation in sunlight has both positive and negative health effects. On the positive side, exposure allows for the synthesis of vitamin D 3. Vitamin D has been suggested as having a wide range of positive health effects, which include strengthening bones [ 1] and possibly ...
Five Suns. The Aztec sun stone. In creation myths, the term " Five Suns " refers to the belief of certain Nahua cultures and Aztec peoples that the world has gone through five distinct cycles of creation and destruction, with the current era being the fifth. It is primarily derived from a combination of myths, cosmologies, and eschatological ...
The solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a nearly periodic 11-year change in the Sun 's activity measured in terms of variations in the number of observed sunspots on the Sun's surface.