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  • This episode of DNews is brought to you by Squarespace.

  • Surfers think catching a gnarly wave is radical? Thanks to some science we can ride air currents

  • at almost the speed of sound with 200 ton surfboards in the sky. How’s that for radical?

  • Hey silver surfers, Julian here for DNews. British airways flight 114 recently made a

  • transatlantic crossing almost an hour quicker than usual, and was clocking ground speeds

  • of 745 miles per hour, or nearly 1,200 kph.

  • It’s been making news because that is a frankly ludicrous speed, considering the speed

  • of sound at that altitude is somewhere around 1100 kph. But when you take into account the

  • airspeed, that is the speed the airplane is traveling through the air around it, instead

  • of the groundspeed it didn’t actually break the sound barrier, which is a good thing because

  • the Boeing 777 really wasn’t designed for that.

  • Fortunately for everyone stuck in coach, the aircraft was riding a particularly ferocious

  • jet stream that was at times over 320 kilometers per hour. But why do we have jet streams?

  • First of all jet streams are not unique to earth. Weve observed them on Jupiter and

  • Saturn. Here on Earth jet streams form in the troposphere, the lowest atmospheric level,

  • and there can be many that swirl and flow and join and split. Most of them head from

  • west to east, so if youve flown from North America to Europe, youve probably noticed

  • your flight is shorter in that direction. The one you and flight 114 cruised on is the

  • northern hemisphere’s polar jet stream. The polar jet streams are from 7 to 12 kilometer

  • up, but each hemisphere also has weaker subtropical jet streams that are 10 to 16 kilometers up.

  • Jet streams form at boundary layers between warm air and cold air. The higher pressure

  • cold air pushes into the low pressure area, and in the winter the pressure differences

  • are greater so you get stronger winds. But the wind doesn’t just move in a straight

  • line from pole to tropics because of the coriolis effect. Basically the planet spinning underneath

  • the moving air deflects it east. Higher in the troposphere there’s less friction so

  • these winds can go unbroken for thousands of miles and voila, jet steam. Throw in modern

  • air travel and if youre lucky you can get where you want to go at almost the speed of

  • sound.

  • Switching gears for a second, we'd like to thank Squarespace for this episode of DNews.

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  • If you don’t think I’ve gone basic enough to explain why there are jet streams, Trace

  • explains air itself here. Also, you were probably one of those kids who kept asking why all

  • the time, huh? I like it, keep it up.

  • So planning a world trip, would you head westerly to ride the current, or east to west to feel

  • like a time traveler? Tough call, but me, I like cruising into the sunset for hours.

  • Let us know in the comments and I’ll see you next time on DNews.

This episode of DNews is brought to you by Squarespace.

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