The Sun is 4.6 billion years old and is currently halfway through its life cycle.

The Sun formed approximately 4.603 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. This age is determined through radiometric dating of the oldest meteorites in the solar system, which formed at the same time. Currently, the Sun is a G-type main-sequence star, often called a yellow dwarf, and it generates energy through nuclear fusion in its core.During this process, the Sun fuses about 600 million tons of hydrogen into helium every second. This stage of a star's life is remarkably stable because the inward pull of gravity is perfectly balanced by the outward pressure of nuclear fusion. Astronomers estimate the Sun's total main-sequence lifespan to be roughly 10 billion years, meaning it is currently in its middle age.In about 5 billion years, the hydrogen in the Sun's core will be exhausted, causing the core to contract and the outer layers to expand. This transformation will turn the Sun into a red giant, likely engulfing Mercury, Venus, and possibly Earth. Eventually, it will shed its outer layers to create a planetary nebula, leaving behind a dense, cooling core known as a white dwarf.The Sun also moves through space, orbiting the center of the Milky Way galaxy at a speed of about 450,000 miles per hour. One complete circuit, known as a galactic year, takes between 225 and 250 million years. Based on its current age, the Sun has completed roughly 20 of these orbits since it first ignited.