Sun

1. The star at the centre of the Solar System, orbited by all the other bodies in the immediate neighbourhood. The thing that people go to the Canary Islands or Hawaii to enjoy a little better. A Type G2 yellow dwarf on the main sequence of the Hertzsprung-Russell diagram, approximately halfway through a lifetime of roughly ten billion years. The planet Earth orbits it at a distance of 93 million miles once a year. The Sun's mass is two times ten to the twenty-seventh tonnes, or a third of a million times the mass of Earth, diameter to the visible disc (photosphere) 853,000 miles. Contains 99.86 percent of the system's total mass. Shines by thermonuclear reactions at the core, where the proton-proton reaction fuses between 700 and 800 million tonnes of hydrogen nuclei into helium nuclei every second, with four or five million tonnes of this mass released as light and other forms of radiation by Einstein's equation E equals mc squared; the photons take about a million years to blunder outwards before reaching the photosphere and flying out into space, where eight minutes later some of them power the weather systems of the Earth and photosynthetic reactions in plants that are directly or indirectly essential to most life on the planet; the ultra-violet radiation that comes with the package may give careless people sunburn. Energy output of the sun at this point in its evolution is 400 million exawatts. Interior structure consists of the core where nuclear fusion takes place, a radiative layer overlying this and a convective layer of progressively smaller convection cells towards the visible surface, physically a little like the patterns in a pot of water boiling on a stove. The sun's visible face is marked by comparatively bright faculae and dark sunspots, associated with localised magnetic fields; large prominences erupt from the disk that in themselves utterly dwarf the planet Earth. Ion storms coming from the sun interfere with Earth-based electronics and may pose a threat to manned space flight. Strengthening gusts in the solar wind interact with Earth's magnetosphere and generate aurorae around the magnetic poles. Solar core temperature is about fifteen million degrees Centigrade, temperature at the photosphere about 6,000 degrees, and temperatures of one to two million degrees are found in the wispy outermost layers of the atmosphere called the corona, from a Latin word meaning "crown". In absolute terms one of the brighter stars in the neighbourhood, although utterly outdone by the galaxy's relatively rare and short-lived supergiants. Orbits the centre of the Milky Way galaxy at a speed of roughly 140 miles per second at a distance of about 30,000 light years, carrying the planets with it, completing one circuit every 225 million years; one of our galactic years ago, the dinosaurs had yet to evolve. 2. A British tabloid paper noted for having a gorgeous babe on page 3. 3. Traditionally the nineteenth card in the Trumps Major of the Tarot deck. In the Rider-Waite version it shows a child riding a white horse with a red cape billowing behind them; further back a row of sunflowers peek over a wall and a rayed Sun-face looks down on everything ... but why are the sunflowers not facing the Sun?