The Sun is a main sequence G2V star with a mass of about 1.9885×1030  KG, more than 300000 times the Earth's mass. The Sun was formed roughly 4.5 Billion Years ago, and is roughly halfway through the main-sequence portion of its life. After 5 billion more years, it will undergo significant changes internally and externally, and eventually dying after running out of things to fuse in its core.  

Its gravity holds the solar system together, keeping everything – from the biggest planets to the smallest particles of debris – in its orbit. The connection and interactions between the Sun and Earth drive the seasons, ocean currents, weather, climate, radiation belts and auroras. Though it is special to us, there are billions of stars like our Sun scattered across the Milky Way galaxy.