801 miles per hour.

That’s how fast a Virgin Atlantic flight was traveling Monday as it was flying high over Pennsylvania.

Basically what happened was this plane was in the right place at the right time. The plane happened to be flying at the same altitude as the “jet streak” (the fastest part of the jet stream – a river of air that was cookin’ at around 230 mph!). So, the plane had a 200+ mph tail wind, combined with a normal airline cruising speed of 600-ish mph. Add those forces up, and you have an airplane pushing 800 mph!

So, as I’m sure you know off the top of your head, the speed of sound is around 767 miles per hour. So, if the plane was at 801 mph, why didn’t it create a sonic boom (which is illegal to do over land)?

Well, it’s because ground speed and air speed are different. The 801 mph is the ground speed, or the speed at which the shadow of the plane is traveling across the ground (thanks to WaPo’s Matthew Cappucci for that visual). For there to be a sonic boom, the AIRSPEED has to be 767 mph. Since the air around the plane was moving at 230 mph, the airspeed was more around 600 mph, not nearly fast enough for a sonic boom (thankfully, because jet airliners aren’t built to handle that).

Think about how fast those people were moving in a historical perspective! How many humans have ever traveled THAT FAST!? A handful of astronauts at jet fighter pilots?

Either way, that plane was moving crazy fast!