If you wanted to mail a letter to an alien pen pal in some distant neighborhood of the universe, you’d need to send more than just your street address to receive a reply. Specifically, you’d need to tell your faraway friend that you live on Earth, the third of eight planets (and five ‘’dwarf planets,’’ but we’ll get to those in a bit) in the solar system, a star system in the Milky Way. Earth’s home galaxy, the Milky Way is a disk-shaped vortex of stars, planets, and clouds of interstellar gas and dust (known as nebulae). The Milky Way is a ‘’barred spiral galaxy,’’ meaning it has several arms and a bar that extend from a bulging core thick with gas, dust, and stars. Everything in the galaxy orbits the core.


Picture Credit : Google