The Milky Way is the galaxy that contains our Solar System. It is a spiral galaxy with a diameter of about 100,000 light-years. It consists of gas, dust, and about 200 billion stars. The Milky Way is just one of billions of galaxies in the Universe.
Our Sun is located in the Milky Way Galaxy about 27,000 light-years from the Galactic Center. The distance from the Sun to the Galactic Center is about 26,000 light-years. There are four spiral arms in the Milky Way: Scutum-Centaurus arm, Sagittarius arm, Perseus arm, and Norma arm. Our Solar System resides in one of these arms called the Orion Spur.
The disk of our galaxy is divided into two regions: an inner region where most star formation takes place, and an outer region where star formation is minimal. Most (about 80%) of the stars in the Milky Way are located in the inner region while only a small fraction (about 20%) are located in the outer region.
The center of our galaxy houses a supermassive black hole that has a mass equal to 4 million times that of our Sun! This black hole was discovered in 1974 by astronomers using radio telescopes.