3 Parts of the Milky Way You Didn't Know

This is the Milky Way Galaxy, where we humans live. It's a pretty standard barred spiral galaxy in the vast universe. If you look at it from top down, you can see that from the center of the Milky Way, several huge spiral arms stretch out. They form a classic spiral shape, including several major spiral arms like the Sagittarius Arm, the Scutum Centaurus Arms, and the Perseus Arm, among others. And our Earth is located on the Orion Arm. We're about 26,000 light years away from the center of the Milky Way. From this spot, whenever night falls, we sometimes get a chance to see the Milky Way's spiral arm structure, that band of light across the night sky, varying in width, which is what we call the Milky Way. Inside these spiral arms, you'll find mostly huge numbers of young stars, colorful clouds of gas and dust called nebulae, and various interstellar dust. They act like tentacles, forming the main disk structure of the entire Milky Way, often called the Galactic Disk. It's about 100,000 light years across. This means even if you had a spaceship traveling at the speed of light, flying from one side of the Milky Way to the other would take you at least 100,000 years. So for humans to travel freely across the universe anytime soon is incredibly difficult, almost like trying to touch the sky. Now, the very bright part at the core of the Galactic Disk is called the Galactic Bulge. When we look at the Milky Way from the side, you can see that the bulge is thicker compared to the rest of the disk. That's because it's the thickest part of the Milky Way, measuring up to 10,000 light years thick. The reason it's so bright in there is because this area also has the highest concentration of stars in the whole galaxy. It's like a giant party for stars. It includes countless red giant stars, and each one's total brightness can be thousands of times greater than our sun's. However, they are all moving at incredibly high speeds, orbiting around a celestial object that humans can't see. This object is located right at the center of the Milky Way, a supermassive black hole. It's named Sagittarius A. Including our sun, the entire Milky Way has at least 200 billion stars, and almost all of them are led by this black hole, orbiting around the galactic center with it. Together, they make up this unbelievably huge celestial system we call the Milky Way. Besides this, the Milky Way is also surrounded by a large spherical halo of light. This part is called the Galactic Halo. It's made up of thin interstellar gas spread all around, as well as spherical collections of stars called globular clusters. These make up the outermost material of the Milky Way. And if you go even further out, you can see the large Magellanic and small Magellanic clouds. These are dwarf galaxies. They are some of the Milky Way's few satellite galaxies. So in short, the Milky Way's structure is made of the Bulge, the Galactic Disc, and the Galactic Halo. Those are the three main parts. Looking at the big picture again, the Milky Way is a sanctuary for countless stars, nebulae, and diverse celestial bodies, big and small. But have you ever thought that even our Milky Way is just a tiny bright spot in the incredibly vast universe? Because huge galaxies like this are simply countless within the observable universe, our Milky Way is just one very ordinary example among them.