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Description
The Sun, a yellow dwarf, is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets, and dust) orbit the Sun,[9] which by itself accounts for about 98.6% of the Solar System's mass. The mean distance of the Sun from the Earth is approximately 149,600,000 kilometers, or 92,960,000 miles, and its light travels this distance in 8.3 minutes. Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis,[10] and drives the Earth's climate and weather.

The surface of the Sun consists of hydrogen (about 74% of its mass, or 92% of its volume), helium (about 24% of mass, 7% of volume), and trace quantities of other elements, including iron, nickel, oxygen, silicon, sulfur, magnesium, carbon, neon, calcium, and chromium.[11] The Sun has a spectral class of G2V. G2 means that it has a surface temperature of approximately 5,780 K (5,500 °C) giving it a white color that often, because of atmospheric scattering, appears yellow when seen from the surface of the Earth. This is a subtractive effect, as the preferential scattering of shorter wavelength light removes enough violet and blue light, leaving a range of frequencies that is perceived by the human eye as yellow. It is this scattering of light at the blue end of the spectrum that gives the surrounding sky its color. When the Sun is low in the sky, even more light is scattered so that the Sun appears orange or even red.[12]

The Sun's spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The V (Roman five) in the spectral class indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium. There are more than 100 million G2 class stars in our galaxy. Once regarded as a small and relatively insignificant star, the Sun is now known to be brighter than 85% of the stars in the galaxy, most of which are red dwarfs.[13]

The Sun orbits the center of the Milky Way galaxy at a distance of approximately 24,000 to 26,000 light years from the galactic center, moving generally in the direction of Cygnus and completing one revolution in about 225–250 million years (one Galactic year). Its orbital speed was thought to be 220±20 km/s, but a new estimate gives 251 km/s.[14] This is equivalent to about one light-year every 1,190 years, and about one AU every 7 days. These measurements of galactic distance and speed are as accurate as can be, given current knowledge, but this may change as more is learned.[15] Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of Hydra with a speed of 550 km/s, the sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo.[16]

The Sun is currently traveling through the Local Interstellar Cloud in the low-density Local Bubble zone of diffuse high-temperature gas, in the inner rim of the Orion Arm of the Milky Way Galaxy, between the larger Perseus and Sagittarius arms of the galaxy. Of the 50 nearest stellar systems within 17 light-years (1.6×1014 km) from the Earth, the Sun ranks 4th in absolute magnitude as a fourth magnitude star (M=4.83).

n Greek mythology the sun was personified as Helios (pronounced /ˈhiliˌɑs/) (Greek: Ἥλιος, Latinized as Helius). Homer often calls him simply Titan or Hyperion, while Hesiod (Theogony 371) and the Homeric Hymn separate him as a son of the Titans Hyperion and Theia (Hesiod) or Euryphaessa (Homeric Hymn) and brother of the goddesses Selene, the moon, and Eos, the dawn. The names of these three were also the common Greek words for sun, moon and dawn.

Helios was imagined as a handsome god crowned with the shining aureole of the sun, who drove the chariot of the sun across the sky each day to earth-circling Oceanus and through the world-ocean returned to the East at night. Homer described Helios's chariot as drawn by solar steeds (Iliad xvi.779); later Pindar described it as drawn by "fire-darting steeds" (Olympian Ode 7.71). Still later, the horses were given fiery names: Pyrios, Aeos, Aethon, and Phlegon.

As time passed, Helios was increasingly identified with the god of light, Apollo. The equivalent of Helios in Roman mythology was Sol, specifically Sol Invictus.

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Nikon D60 + 70-300

Description
The Sun, a yellow dwarf, is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets, and dust) orbit the Sun,[9] which by itself accounts for about 98.6% of the Solar System's mass. The mean distance of the Sun from the Earth is approximately 149,600,000 kilometers, or 92,960,000 miles, and its light travels this distance in 8.3 minutes. Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis,[10] and drives the Earth's climate and weather.

The surface of the Sun consists of hydrogen (about 74% of its mass, or 92% of its volume), helium (about 24% of mass, 7% of volume), and trace quantities of other elements, including iron, nickel, oxygen, silicon, sulfur, magnesium, carbon, neon, calcium, and chromium.[11] The Sun has a spectral class of G2V. G2 means that it has a surface temperature of approximately 5,780 K (5,500 °C) giving it a white color that often, because of atmospheric scattering, appears yellow when seen from the surface of the Earth. This is a subtractive effect, as the preferential scattering of shorter wavelength light removes enough violet and blue light, leaving a range of frequencies that is perceived by the human eye as yellow. It is this scattering of light at the blue end of the spectrum that gives the surrounding sky its color. When the Sun is low in the sky, even more light is scattered so that the Sun appears orange or even red.[12]

The Sun's spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The V (Roman five) in the spectral class indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium. There are more than 100 million G2 class stars in our galaxy. Once regarded as a small and relatively insignificant star, the Sun is now known to be brighter than 85% of the stars in the galaxy, most of which are red dwarfs.[13]

The Sun orbits the center of the Milky Way galaxy at a distance of approximately 24,000 to 26,000 light years from the galactic center, moving generally in the direction of Cygnus and completing one revolution in about 225–250 million years (one Galactic year). Its orbital speed was thought to be 220±20 km/s, but a new estimate gives 251 km/s.[14] This is equivalent to about one light-year every 1,190 years, and about one AU every 7 days. These measurements of galactic distance and speed are as accurate as can be, given current knowledge, but this may change as more is learned.[15] Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of Hydra with a speed of 550 km/s, the sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo.[16]

The Sun is currently traveling through the Local Interstellar Cloud in the low-density Local Bubble zone of diffuse high-temperature gas, in the inner rim of the Orion Arm of the Milky Way Galaxy, between the larger Perseus and Sagittarius arms of the galaxy. Of the 50 nearest stellar systems within 17 light-years (1.6×1014 km) from the Earth, the Sun ranks 4th in absolute magnitude as a fourth magnitude star (M=4.83).

n Greek mythology the sun was personified as Helios (pronounced /ˈhiliˌɑs/) (Greek: Ἥλιος, Latinized as Helius). Homer often calls him simply Titan or Hyperion, while Hesiod (Theogony 371) and the Homeric Hymn separate him as a son of the Titans Hyperion and Theia (Hesiod) or Euryphaessa (Homeric Hymn) and brother of the goddesses Selene, the moon, and Eos, the dawn. The names of these three were also the common Greek words for sun, moon and dawn.

Helios was imagined as a handsome god crowned with the shining aureole of the sun, who drove the chariot of the sun across the sky each day to earth-circling Oceanus and through the world-ocean returned to the East at night. Homer described Helios's chariot as drawn by solar steeds (Iliad xvi.779); later Pindar described it as drawn by "fire-darting steeds" (Olympian Ode 7.71). Still later, the horses were given fiery names: Pyrios, Aeos, Aethon, and Phlegon.

As time passed, Helios was increasingly identified with the god of light, Apollo. The equivalent of Helios in Roman mythology was Sol, specifically Sol Invictus.

=> Wikipédia
-------------------------------------------------------------
Nikon D60 + 70-300