On our rocky planet, covered with oceans, we have learned to measure the passage of time by taking as a basis the trajectory of Earth's movement around the Sun, where a complete revolution corresponds to an Earth year. However, the Earth is part of the solar system, which in turn revolves around the center of our galaxy, the Milky Way. This fact inevitably led to the emergence of the concept of the galactic year.
The motion of the solar system around the center of the Milky Way resembles the orbit of the Earth around the Sun. But instead of rotating around a star, the Sun rotates around a supermassive black hole, which is located in the center of the galaxy. It has an enormous gravitational effect on objects near the center of the galaxy, but at the same time the gravity created by the matter of the Milky Way itself holds the Sun and other stars in its orbit.
According to scientists' calculations, our Sun moves with sufficient speed (about 230 kilometers per second) to orbit around the center of the galaxy and not "fall" into a black hole.
Compared to the Earth year, the galactic year represents time on a larger scale, but it is not a universal unit of measurement for the entire galaxy. What we Earthlings call the galactic year depends on Earth's place in the spiral of the Milky Way. Our galaxy is about 100,000 light-years in diameter, and Earth and the Sun are about 28,000 light-years from the center.
If we imagine the Milky Way as a megalopolis, the Earth will be closer to its outskirts. For stars orbiting a black hole, the center of the "city," the galactic year is relatively short. At the outskirts, the galactic years will already be longer.
According to Keith Hawkins, professor of astronomy at the University of Texas, it takes 220 to 230 million Earth years for the Sun to orbit around the center of the Milky Way. In other words, if we measured time by these galactic "clocks," the Earth would be about 16 years old (in galactic years), the Sun would have formed about 20 years ago, and the Universe would be about 60 years old.