Galaxies are concentrations of stars, gas, dust, and dark matter. They come in a variety of shapes and sizes. Some are fated to collide, like the Milky Way and Andromeda. Credit: NASA and J. Olmsted (STScI) | NASA's James Webb Space Telescope

Ever wonder how far away those stars in the night sky are? 🤔 Our Sun’s nearest neighbor star is about 4 light-years away … our galaxy is over 100,000 light-years wide! But what does that even mean? Check out this Tumblr for a primer: https://nasa.tumblr.com/post/184153458369/how-big-is-our-galaxy-the-milky-way | NASA Universe

37K views · 3.7K reactions | Our galaxy contains billions of other planets, but we know little about them. If we had the chance to study an exoplanet in greater detail, we could learn more about planetary evolution and habitability. Surprisingly, there is a nearby planet we could study that would not only teach us about our planet, but also about many exoplanets. | NASA Solar System Exploration | Facebook