Outer space is the vast, seemingly infinite expanse that exists beyond Earth's atmosphere. It begins at the Kármán line, approximately 100 kilometers above sea level. In outer space, there is very little matter, which means it is almost a perfect vacuum. This environment is characterized by extreme temperatures, radiation, and the absence of air. In outer space, celestial bodies like stars, planets, and moons exist. The Milky Way is the galaxy that contains our solar system, which includes the Sun and its orbiting planets, such as Earth. Outer space is also home to phenomena like black holes and nebulae, which are essential for understanding the universe's formation and evolution.