The Sun

The Sun 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, which by itself accounts for about 99.86% of the Solar System's mass.^[9] The mean distance of the Sun from the Earth is approximately 149.6 million kilometers (1 AU), 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 (0.9833 AU) on the perihelion (around 3 January), to a maximum of 152.1 million kilometers (1.017 AU) on theaphelion (around 4 July).^[10] Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis,^[11] and drives the Earth's climate and weather. The Sun consists ofhydrogen (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.

This series takes a fascinating new look at a very old universe. Fifty years after man first ventured into outer space, we examine the greatest secrets of the heavens. Each episode outlines how humans have explored the universe, and scrutinises the discoveries they have made. We look at hi-tech space telescopes which record the violent birth of stars, robotic rovers which glimpse the red surface of Mars, and sophisticated NASA probes which delve into the mysterious make-up of comets. As the earth churns ominously with the effects of global warming, this is a revealing and prescient journey into the heavens. From the planets to the stars and out to the edge of the unknown, history and science collide in this epic exploration of the Universe and its mysteries. In ‘Secrets of the Sun’, we explore the myriad mysteries which lie beneath the fiery surface of the sun. Our sun is a fireball in the sky - a bubbling, boiling, kinetic sphere of white hot plasma, exploding and erupting. Its size is almost unimaginable: one million Earths would fit within its boundaries. In this violence is born almost all the energy that makes existence on Earth possible. Yet its full mysteries are only now beginning to be understood. From sun spots to solar eclipses, solar flares to solar storms, the birth of the sun to its potential death, discover the science and history behind this celestial object that makes life on Earth possible.

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