The observable universe refers to the portion of the entire universe that we can see and measure from Earth. It extends about 46.5 billion light-years in every direction, encompassing all the galaxies, stars, and cosmic structures that emit light or other forms of radiation. This vast region is limited by the speed of light, meaning we can only observe objects whose light has had enough time to reach us since the beginning of the Big Bang. Within the observable universe, there are an estimated two trillion galaxies, each containing billions of stars. The observable universe is not the entire universe; it is simply the part we can detect. Beyond this boundary, there may be more galaxies and structures, but they remain unseen due to the finite speed of light and the age of the universe.