Where does the atmosphere end and outer space begin?
The definition depends very distinctly on the technology. Astronauts get their space 'wings' when they fly above 50 miles. Stratospheric research balloons can ascend to 30 miles (161,000 feet) for some of the most recent high-altitude research balloons. High altitude manned balloons ascend to 25 miles (132,000 feet) as the edge of space. Some jet fighters define the 'edge of space' as low as 80,000 feet where you can see the black of the sky above and the blue of the earth below and its curvature as well. In reality, the atmosphere just gets less and less dense the higher up you go. Even at 7,000 miles, there is a trace of Earth's 'hydrogen cloud' as its outer atmosphere called the geocorona, and beyond this lies the plasmasphere; an even more remote atmospheric outpost extending to 15,000 miles or more depending on solar storm conditions.
