Earlier in December, Virgin Galactic’s supersonic space plane the VSS Unity reached the upper limits of Earth’s atmosphere in a test flight, reaching a point that many consider the “edge of space.”
As reported by CNN, the rocket-powered plane, flown by two veteran pilots, reached a maximum altitude of 51.4 miles, exceeding the 50-mile altitude that NASA considers the edge of space, but not quite the 62 miles that the widely-accepted Karman Line denotes as the edge of space. This point is vaguely defined, largely due to the nature of Earth’s atmosphere not ending at any particular hight, but rather becoming progressively thinner as altitude increases.