When we look at the night sky, it may seem calm and simple. But in reality, we are standing inside a vast and active galaxy. We live in a universe where everything is connected by gravity.

Stars, planets, and galaxies are constantly moving and interacting. The observable universe stretches about 46 billion light years in radius, containing countless galaxies. Among them, our home is the Milky Way.

The Universe of Galaxies

We can think of the universe as a huge network of structures. Smaller systems like star clusters combine to form galaxies, and galaxies themselves gather into even larger systems. Scientists estimate that there are more than 100 billion galaxies in the observable universe. Each one has its own shape, size, and motion. Together, they form the largest known cosmic structure.

Our Home Galaxy

We live inside the Milky Way, which is just one typical galaxy among billions. It is not especially large or small compared to others. The Milky Way has a diameter of about 160,000 light years and contains hundreds of billions of stars. Our Sun is only one of them. Around the Sun, planets and smaller objects move together, forming our solar system. This solar system is only a tiny part of the galaxy we call home.

Types of Galaxies and the Spiral Form

Galaxies are not all the same. They are generally grouped into spiral, elliptical, lenticular, and irregular types. Spiral galaxies are among the most common forms, making up about 30 percent of known galaxies. The Milky Way belongs to this spiral category. From a distance, it would appear as a large rotating disk with arms extending outward in a graceful spiral shape.

The Central Region of the Milky Way

At the center of the Milky Way lies a dense and powerful region. Scientists believe there is a supermassive black region at the core, with a mass millions of times greater than the Sun. This central region strongly influences the motion of nearby stars and gas. Everything around it moves under its gravitational pull, creating a dynamic and active environment.

The Bright Galactic Bulge

Surrounding the center is a thick, bright area filled with older stars. This region forms a bulge shape and is much denser than the outer parts of the galaxy. It is roughly 20,000 light years wide and about 10,000 light years thick. When viewed from the side, it appears as a glowing central sphere embedded within the flat disk of the galaxy.

Spiral Arms and Our Location

Beyond the central bulge is the galactic disk, which contains most of the Milky Way’s visible matter. This disk is not smooth. Instead, stars and gas are arranged in several spiral arms. The main arms include the Orion Arm, Perseus Arm, Sagittarius Arm, and another outer structure.

We live on the inner edge of the Orion Arm. Our solar system is located about 27,700 light years away from the galactic center. This means we are far from the center, but still part of the galaxy’s main structure.

Motion of the Galaxy and Nearby Systems

The Milky Way is constantly rotating. One full rotation around its center takes about 250 million years. Our solar system moves through space at a speed of around 250 kilometers per second as it orbits the galactic center. This motion is steady and continuous, even though we do not feel it in daily life.

Around the Milky Way, there are also smaller satellite galaxies within several hundred thousand light years. Some of the most known ones include the Large and Small Magellanic Clouds. These smaller galaxies are gravitationally connected to the Milky Way and slowly orbit around it.

Seeing Our Cosmic Journey

Lykkers, when we look at the night sky again, we are not just seeing random points of light. We are observing a vast spiral system in motion. The Milky Way is a structured and rotating galaxy, and we are part of its journey.

We move through space together with billions of stars, carried by the slow rotation of our galaxy. Understanding this helps us see our place in the universe more clearly, and reminds us that our world is part of something much larger and beautifully organized.

The best Milky Way animation, by Gaia

Video by European Space Agency, ESA