How many times has the Sun orbited the Milky Way?

When we think of the movements of objects in outer space, we immediately think of the Earth's rotation and movement. The first, around the same axis, defines days, and the second defines years. However, besides the solar system, our planet also revolves around the Milky Way Galaxy.

At the center of our galaxy is a massive black hole called Sagittarius A*, the same hole that went viral last year with the first image of this type of celestial body. However, determining how many times the Sun orbits Sag A* is not the simplest task.

It is worth noting that the Earth is only 100 million years younger than the Sun, which has just extinguished more than 4.6 billion candles. Its orbit and speed have changed over this period, but even so, scientists are trying to estimate how many times it has completed a loop around the entire Milky Way. Check accounts!

Only this?

A supermassive black hole at the center of the Milky Way Galaxy. (Image: Disclosure/NASA)

Currently, the solar system is moving at an estimated speed of 720 thousand kilometers per hour through the Milky Way Galaxy. However, it is not even close to the lightest stars in our region: the so-called hypervelocity stars, which race through the universe at 8.2 million kilometers per hour!

At its current speed, it takes the Sun about 230 million years to orbit Sag A*. To give you an idea, that's 750 times the lifetime of a human on Earth. Even dinosaurs became extinct in a shorter period of time than that!

Since the Sun is 4.6 billion years old, it might seem safe to say that it has completed at least 20 orbits around the supermassive black hole in the Milky Way, and Earth was next to it 98% of the time. However, this is not entirely the case…

The tenth of the question

(Image: Unsplash)

Currently, the solar system is far from its original place in outer space. Science believes that it was born near the center of the Milky Way Galaxy, after gradually moving away over millions of years in a movement called radial migration.

The Sun appeared 16,300 light-years away from the center of the galaxy, but today it is 26,100 light-years away. When it first appeared, it may have taken 125 million years to completely orbit the Milky Way. Thus, the calculation is a little more complicated than scientists previously imagined.

Therefore, it will be necessary to better understand the speed of radial migration to more accurately determine how many cycles have actually been completed. Today, the solar system appears fixed in its orbit, but scientists have no doubt that it could still move a little farther in the next million eons.