[Music] hi hello this week we're asking is time travel possible and the simple answer is yes and what's more you can try this at home y for this experiment what you're going to need is a clock a wristwatch some sticky tape a very powerful rocket and some aluminum foil first place the clock in a convenient location on the ground next make sure that the watch is firmly attached to your wrist next use the sticky tape to attach yourself to the rocket then fire off the rocket at 99.5% of the speed of light and just enjoy
exploring the universe for a bit steering clear of any black holes that you might find after your watch indicates that a minute has passed use the rocket to return to Earth you should find that although the wristwatch shows that only 1 minute has passed the clock that you left on the ground has shown that a whopping 10 minutes has gone by congratulations you've just time traveled 9 minutes into the future and if you want to go even further into the future simply set your rocket to go closer to the speed of light this is all
down to Einstein's theory of Relativity which unites space and time as SpaceTime and as a result the passage of time starts to depend on how you're moving around in space in the same way that two people taking two different routes to the same destination would measure a different distance to that destination two people moving at different speeds through space time will measure different amounts of time passing even if they end up at the same point in time and we can confirm this using particle physics experiments for example some unstable particles only last for a certain
amount of time know as their lifetime after which they will spontaneously turn into other particles this is known as particle Decay but if we accelerate those unstable particles they very close to the speed of light we find out that they actually last much much longer exactly as we'd expect with Einstein's theory of relativity now of course accelerating a very very tiny particle is relatively easy whereas you'll inevitably come across the problem of having to upgrade your rocket since most Rockets available from your local space agency probably won't be capable of getting close to the speed
of Li oh is that what the aluminium foil is for no no no no uh building a better rocket is just a case of engineering yep well and there's the problems of the g-forces that might kill you when you're accelerating yeah but the aluminium foil is all about the more fundamental question which is once you've made it into the future will you ever be able to come back to the present uh yes now famously traveling backwards in time involves all sorts of horrible paradoxes for example you can go back and end up changing history so
as long as we all keep going forwards in time we won't have that problem and fortunately traveling forwards in time is the only thing that's possible unless you have a traversable wormhole oh yes wormholes they're like black holes only better mhm black holes are regions in space where so much stuff has been concentrated into such a small volume that the fabric of Einstein's SpaceTime has been tremendously distorted that means theoretically speaking a suitable black hole is actually capable of linking up two completely different bits of space and time so I could try to get back
into the past by navigating my way through a black hole but as we've discussed previously if I try to go into a black hole I'll either be ripped to shreds or pummeled by intense radiation oh is that what the aluminium foil is for some sort of radiation Shield or no no no no no uh the uh whole point point is that we're going to use a wormhole instead of a black hole and although wormholes are relations of black holes they don't suffer from these problems like ripping travelers to shreds when they pass through So the
plan is that we're going to create a wormhole it's it's got two ends and you take one of those ends with you when you travel on your rocket into the future right so when I'm done in the future I simply jump into my end of the Wormhole and emerge at the other end at the time where I started I see I see I mean there's just one small problem of course wormholes don't exist well theoretical physicists Michael Morris and Kip Thorn have demonstrated that wormholes are at least consistent with Einstein's theory of relativity all you
need is a large amount of some as yet uninvented exotic matter placed under extreme tension in One Direction and pressure in the other directions I see so we're just left with the engineering problem of having to create entirely new possibly impossible type of matter yeah that's right although there is a more interesting question which is to start creating one of these wormholes you'd need to be able to manipulate the properties of SpaceTime on a microscopic Quantum level and we don't really know whether that's possible I so if we want to travel backwards in time we
need to understand how to unify quantum theory and gravity yeah how are you getting along with that well let's just say that for now if you do travel into the future on a giant rocket you're probably not coming back again which is why you'll need the aluminium foil oh right okay now I still don't see why why You' need it well it's a hat so you blend in better when you're uh stranded in the future okay okay clock check watch check sticky tape oh no actually um ah samandra from number Hub um would you mind
just uh yeah sticking us to the to the rocket with [Music] Y this the uh thank you no that's it that's it's plenty it's plenty it's plenty it's plenty don't don't waste it don't waste it just one cuz we might want to do a trip again later yeah fine thank you okay thanks sticky tape check very powerful rocket check aluminum foil check subscribe to head squeeze check let's go oh
