Space refers to the vast, seemingly infinite expanse that exists beyond Earth's atmosphere, encompassing all celestial bodies, including stars, planets, moons, and galaxies. It is characterized by a near vacuum, where the density of matter is extremely low, and conditions vary widely, from the intense heat of stars to the cold of interstellar space. Space exploration, through missions and telescopes, has expanded our understanding of the universe, revealing phenomena such as black holes, dark matter, and the potential for extraterrestrial life.