{9566}{9682}especially our ideas about the nature of space...

{9710}{9859}To see how, let's first shrink all|of space to a more manageable size.
{9878}{10042}Imagine that the whole universe consisted of|nothing more than my hometown, Manhattan.
{10046}{10206}So now, just one borough of New York City|makes up the entire fabric of space.
{10214}{10378}And just for kicks, let's also imagine that I'm the|CEO of a large corporation with offices on Wall Street.
{10382}{10449}And because time is money, I need to find|the quickest route from my apartment,
{10453}{10583}here in upper Manhattan to my|offices in lower Manhattan.
{10621}{10713}Now, we all know that the shortest distance|between two points is a straight line,
{10717}{10833}but even if there's no traffic-a bit of a|stretch even in our imaginary Manhattan-
{10837}{10961}it'll still take us some|amount of time to get there.
{10981}{11073}By going faster and faster, we|can reduce the travel time.
{11077}{11145}But because nothing can go|faster than the speed of light,
{11149}{11299}there is a definite limit to how much|time we can cut from our journey.
{11413}{11528}This Manhattan Universe fits with|an old, classical vision of space,
{11532}{11653}basically a flat grid that's|static and unchanging.
{11676}{11744}But when Albert Einstein|looked at the fabric of space,
{11748}{11840}he saw something completely different.
{11844}{11978}He said that space wasn't static;|it could warp and stretch.
{11988}{12128}And there could even be unusual|structures of space called "wormholes."
{12132}{12248}A wormhole is a bridge or tunnel that|can link distant regions of space,
{12252}{12342}in effect, a cosmic shortcut.
{12420}{12564}In this kind of universe, my commute|would be a New Yorker's dream.
{12587}{12631}But there's a hitch:
{12635}{12795}to create a wormhole, you've got to rip|or tear a hole in the fabric of space.
{12803}{12871}But can the fabric of space really rip?
{12875}{12967}Can this first step toward forming|a wormhole actually happen?
{12971}{13104}Well, you can't answer these|questions on an empty stomach.
{13259}{13351}Turns out that by looking at my|breakfast-coffee and a doughnu-
{13355}{13542}we can get a pretty good sense of what string theory|says about whether the fabric of space can tear.
{13546}{13614}Imagine that space is shaped like this doughnut.
{13618}{13782}You might think that it would be very different|from a region of space shaped like this coffee cup.
{13786}{13926}But there's a precise sense in which the shape of the|doughnut and the coffee cup are actually the same,
{13930}{14012}just a little disguised.
{14026}{14094}You see, they both have one hole.
{14098}{14238}In the doughnut it's in the middle and|in the coffee cup it's in the handle.
{14242}{14358}That means we can change the doughnut into|the shape of a coffee cup and back again
{14362}{14477}without having to rip or tear the dough at all.
{14481}{14597}Okay, but suppose you want to change the shape|of this doughnut into a very different shape,
{14601}{14669}a shape with no holes.
{14673}{14803}The only way to do that is to|tear the doughnut like this
{14841}{14919}and then re-shape it.
{15033}{15149}Unfortunately, according to|Einstein's laws, this is impossible.
{15153}{15287}They say that space can stretch|and warp, but it cannot rip.
{15345}{15413}Wormholes might exist somewhere fully formed,
{15417}{15556}but you could not rip space to create a|new one, over Manhattan or anywhere else.
{15560}{15677}In other words, I can't take a wormhole to work.
{15728}{15844}But now string theory is giving us|a whole new perspective on space,
{15848}{15964}and it's showing us that|Einstein wasn't always right.
{15968}{16108}To see how, let's take a much|closer look at the spatial fabric.
{16136}{16276}If we could shrink down to about a|millionth of a billionth of our normal size,
{16280}{16388}we'd enter the world of quantum mechanics,
{16400}{16504}the laws that control how atoms behave.
{16519}{16707}It's the world of light and electricity and everything|else that operates at the smallest of scales.
{16711}{16828}Here, the fabric of space is random and chaotic.
{16903}{17003}Rips and tears might be commonplace.
{17023}{17043}But if they were,
{17047}{17210}what would stop a rip in the fabric of|space from creating a cosmic catastrophe?
{17287}{17403}Well, this is where the power of strings comes in.
{17407}{17474}Strings calm the chaos.
{17478}{17621}And as a single string dances|through space, it sweeps out a tube.
{17694}{17786}The tube can act like a bubble|that surrounds the tear,
{17790}{17906}a protective shield with profound implications.
{17958}{18079}Strings actually make it|possible for space to rip.
{18150}{18314}Which means that space is far more dynamic and|changeable than even Albert Einstein thought.
{18318}{18432}So does that mean that wormholes are possible?
{18437}{18553}Will I ever be able to take a stroll on Everest,
{18557}{18639}grab a baguette in Paris