Virgin Galactic founder Richard Branson is set to take off for the edge of space on Sunday. The spacecraft will launch from Spaceport America in New Mexico and the entire process will be live-streamed on Virgin Galactic’s Twitter feed starting at 06:30 PM according to Indian time. Ahead of the launch, several questions have arisen on people’s minds regarding space. If Branson is googled right now, another term that tops the trends and is being searched the most is Kármán line. So what exactly is this ‘Kármán line’ that people are googling so much?
According to National Geographic, Hungarian physicist Theodore von Karman had determined the space boundary to be around 50 miles up, or roughly 80 kilometers above sea level in the 1990s. Through that, the Kármán line is set which, NOAA calls today “an imaginary boundary” that’s 62 miles up or roughly a hundred kilometers above sea level. According to NBC News, 62 miles is also internationally recognised as the ‘Kármán line.’ The Federation Aeronautique Internationale (FAI) too, defines space as beginning a hundred kilometers up.
However, the Federal Aviation Administration, the U.S. Air Force, NOAA, and NASA generally use 50 miles or 80 kilometers as the boundary. The Air Force grants astronaut wings to flyers who go higher than this mark.
The recent curiosity in the Kármán line increased after Jeff Bezos’ team tweeted that their rocket will climb 62 miles, the internationally recognised Kármán line, unlike Virgin Galactic, which will climb 50 miles.
From the beginning, New Shepard was designed to fly above the Kármán line so none of our astronauts have an asterisk next to their name. For 96% of the world’s population, space begins 100 km up at the internationally recognized Kármán line. pic.twitter.com/QRoufBIrUJ— Blue Origin (@blueorigin) July 9, 2021
Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics told National Geographic that there is no easy definition of “space” and “not space,” in part since Earth’s atmosphere doesn’t simply vanish and rather gradually becomes thinner and thinner over about 600 miles.
McDowell reworked on the von Karman math and found that atmospheric contributions on orbiting spacecraft become negligible at around 50 miles up. He told National Geographic, “What you don’t see is satellites dipping down to 70 and coming back out. There is a fairly sharp boundary, a decently sharp boundary, between how low the perigee can be and where you just won’t make it back out again."