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  • Hey, Vsauce, Michael here, and when the pyramids of Giza were built, the tallest was 147 meters

  • tall, making them the tallest things humans had ever built. And they remained that way

  • for nearly 4,000 years. It wasn't even until the 1300's that we finally got around to making

  • something taller, a cathedral in England. So, does that mean that the Great Pyramids

  • of Giza are the "Best tallest structures Of All Time?"

  • Well, to find out more, all aboard the BOAT.

  • So, what is a building? Well, technically, a building is a structure in which at least

  • 50% of its height comes from floor plates where people can live, work, chill out- it

  • has to be habitable. Any less than that and it's not a building- it's a tower. After the

  • Lincoln Cathedral finally surpassed the height of the pyramids, a number of churches continued

  • to be built that kept breaking and setting new records. The next long-term record holder

  • was the Eiffel Tower. It was the tallest thing, ever in history,

  • that we had built, for about 40 years in a row. It was finally surpassed by the Chrysler

  • Building in New York, a personal favorite, which was then quickly bested by the Empire

  • State Building. Now, the Empire State Building is interesting in that it was the first structure

  • ever built by man that was so tall, were you to jump off the top of it, you would actually

  • reach terminal velocity before you hit the bottom. It was the first structure we'd ever

  • built that was so tall, rather than just continuing to accelerate as you fell, you would actually

  • stop accelerating because you would reach the fastest possible speed your limp body

  • could fall at. In the mid 1950's, something weird started to happen: Humans started to

  • build radio and TV towers. These things could be way taller than the buildings that we'd

  • made previously that had to be habitable. And, so, ever since the Empire State Building

  • had its record broken by a TV tower, all these other famously tall buildings, the Petronas

  • Towers, Tapei 101, the World Trade Center, the Willis Tower (formerly Sears Tower)- none

  • have them have ever, within their existence, actually held the title for being the tallest

  • "thing" we've ever built. There was always a radio or TV tower somewhere that was taller.

  • Up until quite recently, and for quite a while, the record for the tallest thing ever built

  • by humans went to the Warsaw radio mast in Poland. It's visually incredibly striking

  • because there aren't any other sky scrapers around it. It's all alone, being very tall.

  • Well, that was until 1991, where some workers exchanging guy-wires made a mistake, and the

  • whole thing started to bend and then snapped in the middle. There's no video of the event

  • happening, but it would have been similar to this collapse, though much, much taller.

  • After the Warsaw radio mast collapsed, the KVLY-TV mast in North Dakota became the tallest,

  • still standing, structure built by man. But, recently, buildings have made a comeback.

  • And, to check that out, we're going to have to travel to the Middle East. This is the

  • first time I've ever touched the Nile. Tadaaa. Ok, so that was me dipping my

  • waterproofed camera into the Nile. If you were to take

  • the entire length of the Nile River and stand it up on it's edge, perpendicular to the Earth,

  • it would reach into outer space about this far, which is pretty impressive. But, where

  • does the space shuttle orbit? And where does the International Space Station orbit? This

  • far away? This far away?? Maybe, this far away? Actually, if this pink, inflatable "Horrible

  • Bosses" ball was the Earth, the space shuttle would orbit about right there. It's incredible,

  • but it's possible because the shuttle, and the International Space Station, travels so

  • quickly. They travel so quickly around the Earth that, instead of seeing one sunrise

  • and sunset every 24 hours, they see 16. But, don't be jealous. You can easily see more

  • than one sunrise and/or sunset in a day by taking advantage of tall structures. So, let's

  • take a look at the tallest structure, the current record holder for the tallest thing

  • humans have ever built, the Burj Khalifa in Dubai. The height of this building blows my

  • mind. You can literally watch the sunset from the base of the building, and then take a

  • super-fast elevator all-the-way up to the top and watch the same sun set again. In fact,

  • the difference in timing between sunset at the base and the

  • top is so significant, the Dubai Islamic Affairs department actually had to make a ruling about

  • when you can start, and break, your fast during Ramadan inside the building. People above

  • floor 80 or higher have to actually wait to start eating 2-3 minutes after the people

  • at the base, because the sun hasn't yet set for those at the top. But, before you head

  • to Dubai to watch the sun rise, or set, twice in a day, keep in mind that the only height

  • you actually need to see two sunrises or sunsets is the height of your own body. Try this the

  • next time you're at a beach. Watch the sun rise, or set, over

  • the water. Water is important because it won't have the terrain or hill issues that land

  • does. Now, let's say you're watching a sunset- begin by laying on your stomach. Watch the

  • sun set, and, as soon as the last little bit of sun goes below the horizon, quickly pop

  • up into a standing position, and, voilá, you'll see the sun's back- part of it's back-

  • and it will set another time.

  • If you take a stopwatch and record the time between the first setting and the second setting

  • that you witness, and, measure the height of your eyes when you're laying down and when

  • you're standing, you can use those numbers to calculate the radius of the Earth.

  • XKCD took this a little bit further by proposing the "Double Sunset Date." Take your date out

  • to the beach in a cherry picker, and, sure enough, it was calculated, given the speed

  • of a cherry picker, all you have to is move about 6 feet up, and you can watch a beautiful

  • sunset all over again.

  • To put things in perspective, the Burj Khalifa is nowhere near as tall as Mount Everest.

  • But, the tallest structure that we could potentially build wouldn't be as tall as Mount Everest-

  • it would be way, way taller. Like, into space taller. Of course, the problem with building

  • things that are really tall is that they get heavier and heavier, and have to support their

  • own weight. But only up to a point.

  • If a structure was so tall that it wound up at the altitude of a geostationary orbit,

  • it would start to feel a new force, not just a gravitational force downward, but, all of

  • the sudden, this new, centrifugal force up, and outward.

  • And so, a building that tall could be stable through tension. And, more than 35,000 KM

  • high. This kind if structure is known as a "Space Elevator."

  • Unfortunately, there aren't any materials known to science today that are strong enough

  • to make building something that large feasable. With the exception, maybe, of Carbon Nanotubes,

  • or Boron-Nitrate Nanotubes. Of course, if we went to a smaller celestial body, like

  • the Moon, we could build one today out of stuff like Kevlar.

  • There are a lot of different things that we have to be wary of when we build a space elevator.

  • For instance, how do we dodge space debris? One solution is to attach the Earth side of

  • the cable to a boat in the ocean that can maneuver around and move the elevator away

  • from dangerous obstacles.

  • Another interesting point is that the taller the cable, the faster the far end of it will

  • be traveling. In fact, if the cable is more than 50,000 KM long, its far end will be travelling

  • near escape velocity, and simply walking outside could take you to the Moon. But, why build

  • a space elevator? Well, because it would be awesome. But also for better reasons too.

  • For instance, right now, in order to send a pound of material into orbit, it costs about

  • 11,000 dollars. But with a space elevator, we could send the same amount of material

  • into orbit for only about 100 bucks. That difference is so significant that Philip Ragan

  • has said that the first country to deploy a space elevator will have a 95% cost advantage,

  • and will possibly be able to control all space related activities. Alright, so here you see,

  • in the mirror, Alex playing guitar while she holds a camera in

  • her mouth and records us. Impressive. I'm here with Kristen from Barely Political. She's

  • visiting London, and if you enjoyed this episode of BOAT, check out other episodes- I've got

  • them all up there. And, as always, thanks for watching. Oh, and check out Kristen's

  • channel right there. Bye! Bye.

Hey, Vsauce, Michael here, and when the pyramids of Giza were built, the tallest was 147 meters

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How High Can We Build?

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    Zenn posted on 2013/06/30
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