The observable Universe stretches roughly 46.5 billion light-years in every direction from Earth, a limit set not by where the Universe actually ends but by how far light has had time to reach us since the Big Bang 13.8 billion years ago. When we peer outward, we encounter objects at wildly different scales: planets confined to our Solar System, stars scattered throughout our galactic neighborhood, galaxies distributed across billions of light-years, and the ancient afterglow of the Big Bang itself at the very edge of what we can see. The size of this observable region isn't fixed by some cosmic wall or boundary; it expands as time passes and light from more distant regions finally reaches us. The distinction matters because the entire Universe itself is almost certainly much larger, possibly infinite, but we can only observe the sphere of space from which light has had time to arrive. This expanding horizon is fundamental to how we understand cosmic distance, galaxy formation, and the structure of everything we can access with telescopes.