The Sun is the star at the center of the Solar System. The mean distance of the Sun from the Earth is approximately 149.6 million kilometers, and its light travels this distance in 8 minutes and 19 seconds. This distance varies throughout the year from a minimum of 147.1 million kilometers (around 3 January), to a maximum of 152.1 million kilometers (around 4 July).
Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis, and drives the Earth’s climate and weather.
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.
The Sun has a spectral class of G2V. G2 means that it has a surface temperature of approximately 5,780 K (5,510 °C) giving it a white color, which often appears as yellow when seen from the surface of the Earth because of atmospheric scattering.
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 believed to be brighter than 85% of the stars in the galaxy.
photo { Pedro Ré | Digital images of the Sun }
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