The observable universe refers to the sphere of space from which electromagnetic radiation has had time to reach detectors since the earliest moments of the cosmos. Due to the finite speed of light, we can only observe regions that are causally connected to us within this timeframe. This observable volume encompasses vast structures, including countless galaxies, dark matter, and dark energy, which collectively constitute the detectable constituents of space. The study of this domain involves mapping the distribution of matter and understanding the physical processes that have influenced its expansion and evolution over cosmic time.