How High Can We Build?

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Jun 03, 2012


How High Can We Build?
How High Can We Build? thumb How High Can We Build? thumb How High Can We Build? thumb


  • 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
  • can 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
  • of 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
  • waterproof camera into the Nile. If you were to take
  • the entire length of the Nile River and stand it up on its 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, travel 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 and 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 very last little bit of the 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 do 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.

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What's the tallest THING we've ever built? How tall will we EVER be able to build?

Follow Michael Stevens: http://www.twitter.com/tweetsauce
music by: http://www.Soundcloud.com/JakeChudnow


see two sunrises/sunsets and calculate the Earth's Radius: http://www.darylscience.com/downloads/DblSunset.pdf

also HERE: http://www.astro.princeton.edu/~dns/teachersguide/MeasECAct.html

Tallest Structures TIMELINE: http://en.wikipedia.org/wiki/Timeline_of_three_tallest_structures_in_the_world

Tallest list incorporating building/structure distinction: http://en.wikipedia.org/wiki/List_of_tallest_buildings_and_structures_in_the_world

falling person and terminal velocity: http://www.newton.dep.anl.gov/askasci/phy00/phy00012.htm

KWTV, first radio mast taller than the Empire State Building: http://www.fybush.com/sites/2004/site-040129.html

radio mast collapse VIDEO: /watch?v=vx4k9gXAZEM

Dubai and Burj Khalifa in fog: /watch?v=vo3pY_jmn2w

Pictures of Burj Khalifa: http://www.owips.com/burj-khalifa/

Burj Khalifa and Ramadan: http://www.emirates247.com/news/emirates/burj-khalifa-residents-must-fast-a-little-longer-2011-08-07-1.411516

Shuttle / ISS height: http://serc.carleton.edu/quantskills/activities/botec_orbit.html

Sunrise from orbit VIDEO: /watch?v=5nF5RXQxDH4

XKCD Date Idea" http://blog.xkcd.com/2009/04/06/a-date-idea-analyzed/

Space elevator: http://www.spaceward.org/ (be sure to enjoy the Conan Space Pirate Toy .gif)



Another possible way to make a super-tall structure: http://en.wikipedia.org/wiki/Space_fountain