The Milky Way is a barred spiral galaxy, our home galaxy, characterized by its distinct pinwheel shape when viewed from above. It has an estimated diameter of 100,000 to 180,000 light-years and is about 1,000 to 3,000 light-years thick. Its structure includes a nucleus, a central bulge, a disk with spiral arms, and a massive halo. Recent observations suggest it has two major spiral arms (Scutum-Centaurus and Perseus) and two less distinct minor arms (Norma and Sagittarius).
Key Facts
- Age: The Milky Way is estimated to be approximately 13.6 billion years old, making it nearly as old as the universe itself.
- Solar System Location: Our Solar System resides on the inner edge of the Orion Arm, a smaller partial arm or spur, located about 25,000 to 27,000 light-years from the Galactic Center.
- Galactic Center: At the heart of the Milky Way lies a supermassive black hole known as Sagittarius A*.
- Local Group: The Milky Way is part of a cluster of over 50 galaxies called the Local Group, with the Andromeda Galaxy being its largest neighbor.
- Rotation: The Solar System takes roughly 240 to 250 million years to complete one full orbit around the center of the Milky Way.
Planets
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
- Pluto