What does 'Edge of Space' mean?

The edge of space is the boundary between the Earth's atmosphere and outer space. The exact altitude of the edge of space varies depending on the definition being used, but it is generally accepted to be around 62 miles (100 kilometres) above the Earth's surface. At this altitude, the Earth's atmosphere becomes too thin to sustain life or support aeronautical flight, and the vacuum of outer space begins.

The edge of space is also known as the Karman line, named after the Hungarian-American engineer and physicist Theodore von Karman. Von Karman proposed this altitude as the boundary between the Earth's atmosphere and outer space in the 1950s, and it has been widely accepted as the standard definition of the edge of space.

The term "edge of space" is sometimes used to describe the altitude at which space travel begins, although it is more commonly used to refer to the boundary between the Earth's atmosphere and outer space. Some people may also use the term to describe the altitude at which space becomes visible to the naked eye, which is around 35,000 feet (10,660 meters). However, this attitude is well below the official boundary of outer space, and it is not considered to be the edge of space. The space simply leaves us fascinated every single time.