A year is the period of time it takes for a planet or asteroid to complete a full orbit around its star, such as the solar year of planet Earth, which is approximately 365 days, which is the period during which our planet completes a complete rotation around its star.

Likewise, a galactic year is the period in which the Sun rotates to complete a full orbit around the supermassive black hole that sits at the center of the Milky Way Galaxy about 28,000 light-years away.

Galactic year

Orbiting the Milky Way only once takes the Sun from about 220 million to 230 million Earth years, according to Keith Hawkins, assistant professor of astronomy at the University of Texas at the University of Texas at Austin, and as reported by the "Life Science" website. (livescience).

In this case, if we measure the time by means of a "galactic clock", the entire age of the Earth will be about 16 galactic years, and the sun will have formed about 20 galactic years, and the age of the universe will be approximately 60 galactic years.

"The journey of the solar system around the galaxy is similar to the Earth's orbit around the sun. However, instead of orbiting a star, the sun revolves around the supermassive black hole that is at the center of the Milky Way galaxy," Hawkins says.

During its journey around the center of the Milky Way, the sun is moving at a very fast speed, estimated at about 230 kilometers per second, which is equivalent to 500,000 miles per hour (804.672 km / hour).

This enables it to continue to rotate around the center of the galaxy in a circle instead of being drawn towards the black hole.

It is also the speed at which an object can travel around the Earth at the equator in 2 minutes 54 seconds.

Our place in the galaxy

Just as the Earth's year differs from the year of the other planets in our solar system, the galactic year with respect to the sun differs from the galactic year with respect to other stars in the same galaxy, and this depends only on the distance of the planet or star from the center around which it is orbiting.

So a galactic year is not a fixed measure across the galaxy.

Hawkins returns to explain, "We can say that the year of the galaxy with respect to the sun is between 220 and 230 million years of the Earth's years. As for the other stars in the galaxy, the year of their galaxy is different."

The diameter of the galaxy is about 100,000 light years, and the Earth is about 28,000 light years away from its center.

"If you imagine the galaxy as a city, then Earth is somewhere near the suburbs," Hawkins explains.

"For stars orbiting near the black hole, the center of the city, the Hungarian year is relatively short," he added.

And he continued: As for the suburbs, where our solar system is located, the galactic years are a little longer.

The galactic year is in which the sun rotates completely around the supermassive black hole at the center of the Milky Way Galaxy (pixels)

Different planetary years

These same rules govern the variation in the length of the year between the planets.

The farther away from the sun, the greater the year of that body.

For example, Mercury, the planet closest to the sun, makes a full orbit around the sun in about 88 Earth days.

As for Mars, its year is equal to 687 days.

The planet Uranus, which is ranked seventh from the sun, rotates around the sun every 84 years, according to Earth's standards.

Pluto, which ceased to be a planet after its demotion in 2006, has the longest year in the main solar system group of 248 Earth years, all of which to complete one orbital period around the sun.

During its journey around the center of the Milky Way, the sun is moving at a speed of about 230 km / second (pixels).

As for Venus, it takes 224.65 days to orbit the sun, which is roughly the same size as Earth.

But the time it takes to complete one day by rotating itself is longer than the time it takes to orbit the sun, so it is the only planet in our solar system that has a day longer than its year.

If the galactic year of the sun is roughly equal to 220 to 230 million Earth years, and if we go back in time to one galactic year, the Earth will be very different, so there is no Internet, no cell phones, not even humans, and the first dinosaurs will be the ones that roam the Earth at that time.