The Observable Universe refers to the portion of the universe that we can see and study from Earth. It is limited by the distance that light has traveled since the beginning of the universe, approximately 13.8 billion years ago. This means we can observe objects that are up to about 46 billion light-years away, due to the expansion of space. Within the observable universe, there are billions of galaxies, each containing millions or even billions of stars, including our own galaxy, the Milky Way. The observable universe is just a small part of the entire universe, which may extend far beyond what we can currently detect.