The Science of Warp Drives - By MITK12Videos
Transcript
00:0-1 | suppose you wanted to take a trip to the North | |
00:02 | Star like actually go there . I hear it's lovely | |
00:04 | this time of century . Well the North Star is | |
00:08 | four million billion miles away and there's a universal speed | |
00:13 | limit , the speed of light . Now we don't | |
00:15 | have any ships that can go even nearly that fast | |
00:17 | . But even if we did it would take over | |
00:19 | 400 years to get there . But what if instead | |
00:23 | of travelling through space we move space around us in | |
00:27 | order to get to our final destination . And what | |
00:29 | if instead of taking 400 years it took more like | |
00:32 | four months now , this sounds like science fiction , | |
00:35 | but Nasa is actually funding some really really early research | |
00:39 | related to the Al Kabeer warp drive which would allow | |
00:42 | us to appear to be breaking the universe of speed | |
00:44 | limit by bending space itself around us . If you | |
00:48 | take a slinky and stretch it out like this , | |
00:50 | it represents the space between Earth and the North Star | |
00:54 | quite a ways to travel . But if we can | |
00:56 | somehow find a way to expand the space behind us | |
00:59 | and contract the space in front of us , then | |
01:02 | we've made it most of the way to the North | |
01:03 | Star without having moved hardly at all . And that | |
01:06 | is exactly how the Al Q . Bert warp Drive | |
01:09 | works . You would contract space far enough in front | |
01:11 | of you and expand space far enough behind you , | |
01:14 | leaving you with a stable bubble to ride in your | |
01:16 | ship . The space in this bubble hasn't been warped | |
01:19 | , so you still experience time , the same way | |
01:21 | you normally would . That's different from if your ship | |
01:24 | itself was traveling close to the speed of light where | |
01:26 | time would pass more slowly . The idea of space | |
01:29 | contracting or expanding sounds weird , but the universe has | |
01:33 | been expanding since the Big Bang and it's been doing | |
01:35 | so faster than the speed of light . So the | |
01:37 | universe started 14 billion years ago from a single point | |
01:40 | with a Big bang . If we assume that it | |
01:42 | started expanding in every direction and the speed of light | |
01:45 | than today , it would be 14 billion light years | |
01:48 | wide , but astronomers have calculated that it's actually over | |
01:51 | three times that size , so this means that it | |
01:54 | must be expanding faster than the speed of light . | |
01:57 | It turns out that the universe is speed limit only | |
01:59 | applies to objects moving through space . Space itself can | |
02:03 | expand and contract at any speed whatsoever , so if | |
02:06 | we can squish and stretch space really fast , we | |
02:10 | can make it seem like we traveled faster than the | |
02:12 | speed of light . So how would we warp space | |
02:15 | like this with mass , You may be familiar with | |
02:18 | Einstein's famous equation , energy is equal to mass times | |
02:21 | the speed of light squared . In other words , | |
02:23 | mass is just another form of energy . Einstein also | |
02:27 | noticed that a lot of energy or mass does something | |
02:30 | funny to space , it contracts it , but in | |
02:33 | order to get enough contraction to build the warp drive | |
02:36 | , you need a lot of mass , bare minimum | |
02:39 | , something as massive as jupiter . And that's the | |
02:41 | easy part . The hard part is figuring out how | |
02:44 | to expand space behind us . It turns out that | |
02:47 | you need negative mass , which is a very weird | |
02:49 | thing . An apple of negative mass is lighter than | |
02:52 | nothing , It's repelled by gravity and falls away from | |
02:56 | the Earth instead of towards Isaac Newton's head . When | |
02:59 | you push it away , it accelerates towards you . | |
03:02 | I mean warping space is weird enough , but negative | |
03:04 | mass that just crosses a line right , turns out | |
03:08 | that negative mass is also technically possible in the field | |
03:11 | , known to physicists as quantum field theory and to | |
03:14 | the rest of the world , that is basically magic | |
03:16 | . You can get negative mass by holding to conducting | |
03:19 | metal plates extremely close to each other . In a | |
03:21 | closed empty space in the universe , virtual particles spontaneously | |
03:26 | and constantly appear bump into each other and disappear . | |
03:30 | The total number of particles appearing and disappearing is the | |
03:33 | same throughout space . So the overall energy or mass | |
03:37 | throughout space is also the same . But if we | |
03:40 | bring our plates together , then they act as a | |
03:43 | filter for particles of certain energy . So fewer particles | |
03:46 | can appear and disappear in the space between them . | |
03:49 | The overall energy , or mass in the space between | |
03:52 | our plates is less than that . In normal space | |
03:55 | effectively , it's negative mass , but it's not like | |
03:58 | a chunk of negative mass that you can just throw | |
04:00 | behind your ship . Plus the positive mass of the | |
04:03 | plates is huge in comparison to the negative mass . | |
04:06 | So any useful effects would be totally cancelled out . | |
04:09 | It's possible that chunks of negative mass do exist . | |
04:12 | They'd be called exotic matter . But even if exotic | |
04:15 | matter is floating around in the universe , it would | |
04:17 | be nearly impossible to find because it's repelled by gravity | |
04:21 | and nowhere near us . And there are some other | |
04:24 | reasons , we're not all hopping on warp drives and | |
04:26 | heading off to the North Star right now , even | |
04:28 | if you did manage to collect enough positive and negative | |
04:31 | mass to get the warp going , the ship would | |
04:33 | be basically unstoppable once you did , because it is | |
04:36 | impossible to communicate with the outside of the bubble . | |
04:39 | And even if you did manage to make it to | |
04:41 | the north star , your warp bubble would pick up | |
04:43 | a bunch of dust and light on the way there | |
04:45 | and all this space drunk would build up a ton | |
04:48 | of energy at the edge of the warp bubble . | |
04:49 | So when you go to return space to its normal | |
04:52 | shape , in order to land all that high energy | |
04:55 | space stuff would basically blast every living thing in your | |
04:58 | destination into oblivion . So all Nasa is doing now | |
05:03 | is trying to create a teeny tiny warp fields in | |
05:05 | order to see if this sort of thing is even | |
05:07 | possible and if it is , we're still probably a | |
05:10 | millennium away from actually using it . If you want | |
05:13 | to learn more , you should check out some of | |
05:15 | the links below and until then if you want to | |
05:18 | get to the North Star , I guess you're better | |
05:20 | off just hitchhiking . |
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