Our galaxy is known as the Milky Way, a barred spiral galaxy that includes our solar system. Its name derives from its appearance as a dim band of light stretching across the night sky, formed by a dense concentration of stars. This band is most visible in areas with little light pollution.
The Milky Way is approximately 100,000 light-years in diameter and consists of at least 100 billion stars, although some estimates go as high as 400 billion. Our solar system is located in one of the galaxy's spiral arms, called the Orion Arm, situated roughly 27,000 light-years from the galactic center.
This galaxy is part of the Local Group of galaxies, which contains more than 54 other galaxies, including the Andromeda Galaxy, and forms part of the larger Virgo Supercluster. Interestingly, the Milky Way is also on a collision course with the Andromeda Galaxy, projected to occur in about 4.5 billion years. When these two galaxies collide, it will result in further star formation and could potentially lead to the merger of the two galaxies into a single, larger galaxy.
The Milky Way has several intriguing features, including dark matter, which is believed to make up about 85% of the total mass of the galaxy. Dark matter does not emit, absorb, or reflect light, making it invisible and detectable only through its gravitational effects on visible matter. Additionally, the Milky Way houses a supermassive black hole, Sagittarius A*, located at the center of our galaxy, with a mass equivalent to around 4 million suns.
In ancient times, the Milky Way has captured the imagination of various cultures, often being portrayed in myths and stories. For example, in Greek mythology, it was associated with the milk of the goddess Hera, creating a connection to its current name. The Milky Way is a defining feature of our universe, providing a home for countless celestial wonders and an observable backdrop for astronomical studies.