How To Build A Time Machine | Weird Science | Earth Science

[Music] you must have had that daydream at least once if you could time travel would you go into the distant past or would you go far into the future it'd be fun to walk around with dinosaurs i would travel to the future all the way to the very end but ron mallet is different now according to my calculations he thinks he already knows how to build a time machine i think of myself as just being an ordinary person with a passion and my passion is the possibility of time travel get ready this is some pretty weird science according to my calculations the space inside this should actually become twisted but ron's quest doesn't start here it's soap smacking it begins when he was just 10. my father was was an incredible person for me the sun rose and set on him and then it was uh all taken away suddenly when ron's father died he became obsessed with the idea of time travel dreaming of one day building a time machine to go back in time and save his dad i would say you know dad two things i love you and stop smoking it obviously sounds pretty out there but time is truly mind-bending this is how some of the world's most intelligent people try to explain time so what is time so time is that's the that's that's an excellent question time is the uh change of uh uh so clearly that it's difficult yeah it's really difficult and if even trying to explain time can stump some of the world's greatest minds then it's probably worth at least asking is time travel possible uh yeah it is time travel is not only possible but we've already done it and you've done it too every time that you've been in a plane a train a car if you've run really fast that is because that time is not absolute it is warped by velocity and gravity so here's a way to wrap your head around that mission and lift off of the space shuttle endeavor extending out this is peggy whiston the first female commander of the international space station she spent a lot of time in space 665 days to be precise and here's the thing because of all the time she spent up there she's literally younger than she would have been if she stayed on earth three new residents headed for the international space station this is because of something called time dilation which einstein discovered in his theory of special relativity it basically says that time is different for different observers and that it can be warped by velocity and gravitational potential so two clocks run at different speeds if for example you are stood still and your friend is on a high-speed train then because your friend is traveling at a higher velocity that means that their clock is slowed down compared to yours this applies to peggy too she spent so much time in orbit traveling at a speed of 7.66 kilometers per second that she's actually younger than she would have been had she stayed here on earth okay only by 0.002 seconds but this is a real example of time travel in action and what if she'd been traveling even faster it's these weird properties of time that have excited the imaginations of would-be time travelers ever since einstein announced his theory of special relativity including ron mallett and he claims to know how to do it so how do you build a time machine this is ron's prototype for his time machine his idea is to use einstein's theory of general relativity to twist the very fabric of space-time using light or lasers to be precise in einstein's general theory of relativity space acts like a medium sort of a fabric and that fabric can be altered by using matter or energy this device is a representation of the equations that i found solving einstein's equations for gravity i'm going to turn the device on and bring up the voltage then we'll use vapor from dry ice to make the beams visible now you can see the beams as they're scattering off of the vapor and you can't see of course the light beam is moving around and this creates what's known as a circulating beam of light now according to my calculations the space inside this should actually become twisted okay pause so ron's thinking is that if gravity can affect time and light can affect gravity why not combine those ideas and use light to affect time that's why he's got these laser beams ron suggests that if you can use those laser beams to twist space time strongly enough then you could travel back into the past this equation says if you increase the intensity enough then you actually can cause time to be twisted and what this means is that if this is a timeline that we all live along this represents the past the present and the future and we're all carried along this river of time from the past present to the future now the thing is is that if space is being twisted strongly enough then what's going to happen is that this timeline this linear timeline is going to twist it into a loop so if time now all of a sudden becomes a loop that means that this allows us for the possibility of traveling back into the past so you might be thinking well why don't we have a time machine yet there are a few reasons as to why so first of all ron says that we need vast amounts of energy and to go with it vast amounts of money which so far no one has yet been willing to foot the bill but there are some people who have even bigger problems with it the experiment might need to be the size of the universe for it to actually work or you need as much energy as would be required to form a black hole or that the equations don't even work with our particular universe so just small problems then and even if everything did work there's still one problem for ron and that you'd only ever be able to go back in time to the point in which you turned on the machine so to conclude wait got a bit more time okay if that wasn't mind-bending enough try this one for size the current generally accepted view in terms of how to think of time is that the universe is an unchanging block of space time that there's no past present or future that they all just co-exist simultaneously and this is known as the block universe model most notably what's important about the model is the idea that wait hold on can we just take a second to appreciate the fact that the center for time is a place that exists okay good philosopher christy miller works there what's important about the model is the idea that the past present and future are all equally real so you can think of everything that ever did exist does exist or will exist as all somehow being out there in space time so the dinosaurs are all out there somewhere in the past doing dinosaur stuff we're all here now and all of the future is all out there somewhere in space time too one way of thinking about this model is that other places in time are just like other places in space so just as we are here in sydney but there's other people located in singapore and london and those places are perfectly real it's just that we aren't at them okay so clearly we can't even fully agree on how to conceptualize time there are still intense disagreements about whether or not time even flows from one moment to the next but we can agree that building a functioning time machine is still tantalizingly out of reach but maybe it's just a matter of you

Channel: BBC Earth Science

Views: 217,751

Keywords: bbc earth lab, earth lab, science, chemistry, physics, why, biology, space

Id: caDTre23eyE

Length: 9min 19sec (559 seconds)

Published: Tue Dec 14 2021