Sun has a form of a giant ball, made out of gas, mostly hydrogen and helium. Surface temperature is about 5.700°C, while on the inside, this nuclear reactor reaches up to 15 million °C. Sun's diameter is 109 times bigger than Earth's. Every day, it travels (visually!) 1°, it rules a sign for a month, and the Zodiac passes in a year. It's element is fire, and it is the strongest while in Leo, and strong enough in Aries.
Sun gives light and life, but can also terminate it (summer fires, droughts and sunburns). It affects people's heart, blood pressure, eyesight, spine. Characteristics it gives people are: vitality, activity, liveliness, dignity, will, prestige, authority, power of feelings, social power, organization, success and high political positions. With men, it means manhood, maturity, creativity, generosity, and with women an important role in her life: husband, father, brother, lover etc.
If it is harmonically aligned with other planets in an individual's horoscope, it gives a person joy of life, positive character, passion, aristocratic behaviour, pride, dignity, social climb, rich spiritual life. Unharmonical Sun is cause for narcism, theatrical behaviour, despotism, cruelty, egoism, arrogance, patriarchy, and such a person always uses force.
The sign Sun is in currently, discovers the deepest nature of some person, but this doesn't have to mean that she will act the way it is characteristic for this sign. Sun symbolises a rising path, path of individualism... sign with Sun in it shows a way which is the best to follow this path. Basically, Sun represents the way how someone can reach balance with himself. Considering Earth, Sun is it's energy source, central thing around whom everyone go.
Ego, glow, light, warmness, impulse of life. It rules the sign of Leo and the 5th house of the Zodiac. Sun's metal is the gold, and colors gold, and all colors from dawn to sunset.
Biological manifestations: health, vitality, heart, circulation (brain, right eye with men, left one with women, right side of body), spine.
Psychological manifestations: will to live, joy of life, generosity.
Sociological manifestations: men, father, authority.