What is the orbital period of the Sun around the Galactic Center in millions of years?

The Sun’s orbital period around the Galactic Center is about 225 million years. This interval is called a galactic year, or cosmic year, and it measures one complete trip of the Solar System around the center of the Milky Way.

The Sun is about 26,000–27,000 light-years from the Galactic Center, where the black hole Sagittarius A* resides. It does not orbit that black hole alone in the way Earth orbits the Sun; the Sun’s path is governed by the combined gravitational pull of stars, gas, and dark matter throughout the Galaxy.

The Solar System travels around the Galaxy at an average speed of roughly 230 kilometers per second. Even at that speed, the enormous circumference of its orbit makes one revolution last hundreds of millions of years. Since the Sun formed about 4.6 billion years ago, it has completed only around 20 galactic orbits.

A galactic year is useful for placing Earth’s history in cosmic perspective. Modern humans appeared during only a tiny fraction of the Sun’s latest trip around the Galaxy.