The Sun is the star at the center of the Solar System. It is an ordinary star, one of about 100 billion in our galaxy, the Milky Way. Here are some key facts about the Sun:

• Formation: The Sun formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud.

• Size and Mass: The Sun is a G-type main-sequence star that makes up about 99.86% of the mass of the Solar System. It is about 109 times the diameter of the Earth, and more than a million Earths would fit inside the Sun.

• Composition: The Sun is made up mostly of hydrogen, followed by helium. Nearly all the remaining matter consists of seven other elements — oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon.

• Color: The Sun is informally called a yellow dwarf, though its light is actually white.

• Function: The Sun has extremely important influences on our planet. It drives weather, ocean currents, seasons, and climate, and makes plant life possible through photosynthesis.

• Lifecycle: The Sun is currently in a stage called yellow dwarf and is about 4.5 billion years old. In another 5 billion years, it will become a big, cool star called a red giant. A few billion years after that, it will become a small white dwarf star.

The Sun has been an object of veneration in many cultures throughout human history. Without the Suns heat and light, life on Earth would not exist.