When we leave our solar system and enter interstellar space, we're a far ways from home on Earth. But we're still within the Milky Way Galaxy! What IS a galaxy? Watch: https://youtu.be/Aeb4yoPRk9w | NASA - National Aeronautics and Space Administration

70K views · 1.3K reactions | What are the primary categories that astronomers use to classify galaxies? How do these categories relate to the age, composition, and structure of galaxies? | The Brain Maze | Facebook

Why Galaxies have Spiral Arms?! - The majestic spiral arms of galaxies are a source of wonder, but what exactly causes them to form? Is it the swirling dance of stars as they orbit the galactic center, or something more mysterious? Does the speed at which different parts of the galaxy rotate play a role? And why don't these arms simply wind up and disappear over time? | The Brain Maze