Visit best friends dot org slash puppy mills to learn more before 7 Sacramento's news traffic and weather news radio Ok of p.k. . News Radio j f b j Sacramento. To sever mono and k f b k f m public Pods your top stories in the 60 seconds but 1st traffic and weather together from the k m b k traffic center expect delays on I 5 do construction northbound just before Airport Boulevard to a mile after Airport Boulevard very thick right now on that stretch down at least one lane there for construction until 5 am always right now things are flowing pretty freely on major freeways and sacramental Interstate 80 is looking good from the bay through the foothills in both directions Highway 50 flowing freely from Sacramento to Tonto in both directions next updated 130 from the West Haven solar traffic center Newsradio k. Of b.k. 93 point one f.m. 1530 am. Mostly clear skies through the night tonight allowing temperatures to drop off into the mid to low fifty's for your Monday morning we will have mostly sunny the sunny skies for you Monday afternoon with temperatures climbing into the mid to low eighty's and will continue to warm through Tuesday before we see some cooling meteorologist Dr Dorn on his radio case became. I'm Caroline Byrne's Newsradio k f e k our top story Sacramento County Public Health is looking into several cases of botulism linked to food bought at the Balliol food and fuel gas station in Walnut Grove public health teams are working with the county department of environmental management to stop the sale of prepared food items at that location botulism is rare but serious paralytic illness public health officer Dr Olivia because Syria they describe some of the symptoms could stack. The king but the more serious and. Slurred speech decision and problem and muscle weakness and the one that we worry most about. That having difficulty breathing public health is asking people who consume prepare food from the Valley Oak food and fuel from April 23rd through today and it. Experienced any of those symptoms to please contact their health care provider Texas governor Greg Abbott has signed a law targeting so-called sanctuary cities that allows police to ask about a person's immigration status it also threatens sheriffs with jail if they don't cooperate with federal authorities Republican Abbott Sunday took the unusual step of signing the bill on Facebook with a little advance notice c.b.s. News correspondent all Marbella Franco has more from Dallas the legislative action comes after weeks of heated debate and political jousting Ameren current. State Senator Charles Perry who co-sponsored the measure claims this bill will make Texas community safer it's about protecting our communities we don't want those individuals that committed crimes illegal or otherwise when they had an option to be locked up for public safety to be released at the discretion of the local law enforcement the bill will give every Texas police officer and sheriff's deputy the power to enforce federal immigration law peace officers can ask the immigration status of anyone under arrest or even detained. Every major police chief in Texas oppose the bill and that's according to The Associated Press French president elect Emmanuel mock groan spoke in front of a crowd of supporters for the 1st time at the Louve Mrs thank you Mitzi that put up thank you for being here thank you for having time to do it is courage benevolence for so many moans political says this is even ing you have won France has. Thanked his supporters for their time trust and risks some took the French government released results as of 10 pm and France showing macro with just under 58 percent of the vote the far right candidate Marine Le Pen's 42 percent and the average price of a gallon of regular grade gasoline dropped $0.05 nationally over the past 2 weeks to $241.00 the average price in Sacramento is to $85.00 a gallon will stay connected you news alerts immediately if they have to Gay dot com I'm Carolyn Burns Newsradio b.k. 93 point one f.m. And 1530 am. Regard radio pretty easy in fact we pride ourselves on day listening to music should be our Heart Radio lets you at your music collection and your radio stations together in a single lap a misprint Michael's. My heart rate card radio is easy go ahead and spread the word we don't. See teens at 4 music and radio free i Heart Radio ads. I heard radio puts the spotlight on fun fun was formed in 2008 when the roots formally the format recorded Intrade film trailer for This Is 40 all things fun is using and more are on i Heart Radio keyword fun. Terms for. This is coast to coast am. Now here's your guest host Richard Serra. Etta James'. I'd Rather Go Blind That sounds serious in the Welcome back to coast to coast am coming to you live from coast Serrano affiliate talk radio am 640. I mentioned the cold in the rain here in Toronto and while I was being kept indoors for part of the week with all that I sat down and I enjoyed my National Post and had a pot of tea and I read this here is what time travel will look like once we invent it b.c. Scientist crunches the numbers that's the headline travelling back in time the story continues is probably still impossible but just in case a.b.c. Mathematician has done the math on what it looks like or what it will look like specifically u.b.c. Theoretical physicist Ben Tippit has produced a 12 page paper plotting out the precise geometric behavior of a phone booth shaped time machine the travels in a loop constantly shifting backwards and forwards through time published in The Journal classical and quantum gravity of the paper calls its time machine the traversable a causal retrograde domain in space time Tartus an obvious reference to the phone booth shape Tardis time machine the long running British t.v. Series Dr Who scientists of long understood it's possible to build a machine to accelerate our forward travel through time that's called Time dilation a concept 1st drawn up by Albert Einstein and later proved by experimentation. The song 39 by Queen guitarist Brian May nicely sums up the phenomenon in it in its extreme form in the song a space traveler voyages at very near the speed of light for what seems to be a year but when he returns the earth has aged 100 years his friends are dead and his infant daughter is a Zen centenarian the trickier prospect with time travel however is going into the past to work the Tardis needs to exist within a closed timelike curve a loop in space time that keeps returning to the same point in space and time theoretical physicists have determined that such a curve is indeed a mathematical possibility. Dr tippets Tartus when coast to coast am continues. I go presents a voicemail from your friend washing machine. Its washing machine it's about 7 o'clock on Wednesday so good is that 1st I found your last sock exciting also and might be flooded the whole basement is going to be pretty expensive but hey at least you got that so your washing machine won't pay for water damage Luckily one call to the Geico Insurance Agency makes it easy to switch and save on homeowner's insurance as a small business owner if you don't have satisfied customers you don't have anything at Vistaprint we feel the same way about making sure you are satisfied with every business card you order go to vistaprint dot com today and you can get 500 customized high quality business cards starting at just 99 and if you aren't satisfied for any reason will make it right get 500 business cards and complete satisfaction starting at just 99 at vistaprint dot com Use promo code 3344 at checkout that's vistaprint dot com promo code 33442 little tablets is all it takes to make your thin hair feel and look thicker and fuller guaranteed business gal is the number one drug free hair growth supplement in the u.s. With one box being sold every minute globally it's clinically researched to promote existing hair growth for men and women and now a 90 day supply of it is gala is offered in your area risk free plus free shipping call 807-078-7835 this gal nourishes than hair from within you will love your hair growth results guaranteed this gal is so effective it's recommended by top doctors Here's Dr John Laura as a control just I feel competent recommending to scale it back by 25 years of research and multiple clinical studies to demonstrate it has goals effect of promoting the growth of poor want to try Biscoe every listener that calls now gets a 90 day risk free supply plus free shipping Call now $8707783587077835.00 that's 807077835. Dr Ben Tippett is a theoretical physicist and mathematician he received his Ph d. From the math department at the University of New Brunswick Canada he contributes to the science sort of podcast as the on call Canadian in his spare time he likes to write papers about superhero physics or zombies as well as research on black holes gravity and gravitational lensing as he cloaking method He's currently a math and physics instructor at the University of British Columbia Okanagan campus documentable welcome to coast to coast and thanks for hanging out with us how are you oh hello Richard I am so good can I start by saying what an honor it is to be here. Certainly and start that way thank you because since I was a teenager it's amazing because your your show the show it it it works on a type of entertainment that you don't get anywhere else and that's the entertainment of fascination people right listen to it in the you know in the middle and we all like ghost stories but you have people on explaining things from from the ground up and the real thing that gets everybody listening keeps everybody listening if the idea is that you can get drawn into an explanation that you can do you can understand things and it's a wonderful feeling and frankly almost nobody is is building entertainment empires on the idea that you can just fascinate people with explanations and it's lovely I started a podcast a physics podcast just because I was so inspired by the work coast to coast does it's just it's an honor to be here thank you very well Wow Well it's great having you and that's high praise indeed and that was a very inspiring. Soliloquy if I can see it now let me ask you the premise here just so I understand because I have I I don't know if you're familiar with Professor Ronald Mallett from the University of Connecticut and his work on devising a theoretical a time machine and it wouldn't just to be clear it wouldn't it wouldn't transport a human back in time or forward in time it would it could transport bits of information so it could be used as an early warning signal for example however. Dr mallets inspiration for creating his theoretical time machine was eventually he wanted to go back in time to save his father who died and a very young age back in 1980 very touching story but your saying just be clear time travel to the past is possible we know that travel into the future by just nanoseconds is possible but you're also saying travel into the past is now mathematically feasible or not feasible possible possible Yeah yeah well Richard is it Richard Mallett was that the sun is now Professor Ronald Mallett rolling over Sedona Yes that's right yeah now I'm familiar with his story a little bit less his work. But. The deal is essentially both he and I and everybody else who's done the research on time travel is working within the same mathematical framework right so in. Mathematical models that allow people to travel backwards in time have existed since the 1950 s. In my field in the field of Einstein's curved space time was that right Ok Oh yeah yeah yeah yeah every you know Einstein best friend a man named Kurt Godel used to walk to school together they both worked at Princeton together Kurt Godel is a famous logistician it was Einstein 70th birthday party and Kurt Godel presented him with a mathematical way that time travel can happen as a birthday present. We've been in my field we've been talking about the possibility since the 1950 s. . We have this discussion for variety of reasons sometimes it's it's personal sometimes we want to go interact with a family member but in other cases we're just exploring the possibility it's about the math it's about the the journal the inquiry that we're trying to do and so unfortunately fortunately and unfortunately. In our case in the case that we are mathematically exploring with my Tardis it's possible for someone to go back in time but it's not possible to change the past in any way. And also I should add a few caviar I know it's the middle of the night and nobody wants to hear about mathematics but there's a big distinction between mathematically possible and physically possible in a way that's going to happen to morrow right right this is kind of mathematically possible in the same way you can say it's mathematically possible to calculate how fast a person would need to jump in order to jump over the moon you can calculate right but I had seen that you should spend the next 20 years doing squats hoping that it's going to happen I think the other example is the you were quoted in The National Post saying it's it's possible that a snake could go to Harvard but not feasible not likely. That's the easy i do we thought that that Einstein's General General Relativity had showed you how much I know General Relativity had ruled out time travel to the past but so that's off the dock and I'm mistaken about that but you're saying you cannot if you travel back to the past you cannot change the past which would then rule out the grandfather paradox which was one of the stumbling blocks to travelling back in time correct. That's Well essentially that's right. The the the rule here the rule of thumb that the people in my field work with it's called Novikov self-consistency condition. And it sounds like a rule imposed by you know God looking at the universe from outside putting down his hammer the rule says that you can't change the past even though you can interact with it. Another way of saying it is if you interact with the past in your future journey through time then all of those things that you did will have already happened it's very difficult linguistically to talk of a time travel because your future when you travel backwards in time is the same as your past when you interact with your future self Oh dear please don't. Think of this. So. Then are you does that mean because you can't interact with it with the past or you can't change the past does that mean you're actually you're it's not technically wouldn't be time travel you're you're travelling to a different like almost a parallel universe a different timeline entirely moon you know I find that when I'm trying to explain this the easiest way to do it is to make reference to some movies so the the the debate here is which movie is time travel most like mathematically lots of people are familiar with the movie Back to the future where Marty McFly interacts with his past well not his past self is his parents in their past and in doing so either you know he starts to fade out of existence when he mocks too much around with the right that's the grandfather paradox that's the grandfather paradox the resolution of it no because self-consistency condition is a lot more like the movie 12 Monkeys where Brad Pitt remembers a child being tussled around he was he was present when the bad guy. With this horrible virus went through the airport and then as a future person living in the in the terrible future he's used it as to go back to the past to figure out who this person with the virus is and stop him and it turns out that the whole kerfuffle he saw at the airport the thing inspiring him to go back into the past was essentially his future self in this case he interacted with his self but only in a way that causes the events to unfold in the way they did you end up with a self-consistent chain of causal events. Ok yeah that sort of makes sense i love how you you take this out of the realm of mathematics and into the realm of cinema which is you know I wish I had you as a mathematics professor. Now one of the things you say that is important to understand here is that the idea of dividing space into 3 dimensions with time in a separate dimension by itself that's where we got off on the wrong foot that's a mistake. Well yeah. So I definitely said I definitely spoke about that in the various articles that have been written about me the technical article traversable a causal retrograde Jermaine's in spacetime is that is pure mathematics if one of the listeners wanted to dig it up off the Internet I think you have to pay to access it your eyes would definitely fall out because it's full of well I don't want to say technical jargon but it's full of technical terminology. But one of the big discoveries that Einstein and the other people who worked with him on the theory of relativity back in you know 100 years ago one of the big revolutionary ideas they came up with was the idea that time wasn't independent of our 3 spatial dimensions that they were had somehow stuck together. We're right right sure but one of the consequences this is that the rate that time passes the simplest consequence of this is that the rate of time the time passes depends on your motion and you mentioned this before this is this is what let's talk about future time travel if you're travelling in Iraq it down to a distant star and you come back you might end up much younger than everybody else because less time has passed for you than everybody at home. Exactly twin paradox. So that that that effect the twin paradox comes about from the fact that time is stuck to the other dimensions giving you a 4 dimensional system called spacetime. Does that start to make sense. Of the twin paradox doesn't make any sense formally outside of your arguments unless you unify space and time together right now Ok so tell me about this. The Tardis. We're all familiar with the Tardis from Dr Who of course so you incidentally that acronym that you have was that the was that would Tardis actually stood for in the Dr Who series in Dr Who The the acronym Tardis stands for time and relative dimension in space Ok So they've got some relativity ideas in there but nobody's quite sure where they came up with that acronym or whether or not it supposed to mean anything there's been a lot of retroactive associating meanings to it in the television show so we wanted to come up with an acronym that spelled out Tartus t a r d s you know in a way that actually describes our time machine. All right reversible Yeah Tom Tell me more about about how this theoretically this this would work and what we would experience if we went into this telephone booth shape time machine All right so here's the here's the tricky business. A few moments ago we were talking about how space and time are kind of fastened together right correct turns out that the direction that a person takes through space time the direction that they feel in terms of increasing time is called the arrow of time their local arrow of time is kind of independent of the arrow of time for things around them and the distinction between the direction of your arrow of time is comes about from motion and it comes about from curvature so so what we have here is I use the curvature of space time to make it so the arrow of time for the people inside the box it starts out going forward forward in time just like the people outside but then it turns it turned sideways and then it turns Packwood's in times of the people inside the box or moving backwards in time and then turn sideways and it forms a closed loop so that's. You moving even front words and and you moving frontwards and backwards 1st you move in front of words in time and then you move sideways in time and then you move backwards in time and then you can get out of your own way so you can get out of your own way that's exactly the case you need to get out of your own way you don't want to run into yourself as you move so. This is this is a this is a lovely picture because the people inside the Time Machine are going to see something very dramatic different from the people outside the Time Machine. If you're outside the Time Machine you're going to see 2 versions of the box. Right and. If you can look into the window of the boxes you'll see that the person in one window will have time moving for let's say the the person inside the box has a big wrist watch and if you're outside the watch outside the box you can look at the person inside a wristwatch and in one box it will be moving clockwise forwards in time and if you look at the other person in the other box there the hands of their watch are going to go backwards backwards in time and then if you're inside the box on the other hand you only feel time going forwards you look at your wrist watch and the hands of the wristwatch are always going clockwise. If you look outside the box so what you'll see because you're going in a circle is sometimes your area of time is going to align with the arrow of time outside the box and you will see say there's a clock tower out surge your laboratory you'll see the hands of that clock tower will turn clockwise times going forward and then you'll see the hands stop times going sideways and reverse their direction they'll start going counterclockwise time will reverse outside your window for beefier time and stop and then go in the right direction over and over and over and the fun bit here is if you look out your window to the left you're going to see another box so you're inside the Time Machine you look out the window and you see another time machine and Inside Out Of The Time Machine is another version of you and if you look at the hands of the watch the other person in the other box their watch is going counterclockwise time is going in reverse usually to spell that out with like breakfast analogy. Or I love a good breakfast analogy Ok so. Let's say you're in your Tardis your time machine right time is going in a circle for you what does that mean how does that look. You're making breakfast you take out your your cream you pour it into your coffee you crack an egg into the pan it fries Ok got it if you look out the window to your doppelganger the other box the one that's going in the opposite direction in time that person's going to be pulling cream out of their coffee they're going to be taking eggs putting them in a pan under frying them and putting them back in their eggshells reassembling the eggs on the other hand somebody outside the box is going to see 2 things they're going to see one box where the person is making breakfast as usual and the other box they're going to see somebody disassembling their breakfast pulling the cream out of their coffee and cracking their eggs. That's good fun it's of it's and have to list ration Absolutely Dr Ben Tippett is with us from the University of British Columbia and he says mathematically time travel to the past is possible this was a 12 page paper how was it received by yet Well obviously it's a peer review journal but what it would what we're coming up on a break but just give me a sense now before we head into the break what was sort of the what was it of the the vibe that you're getting from your from your colleagues in the field well the reviewers asked me for lots of reviews. But in the end I did the reviews and a couple. Well how much time do you have for the break. Probably 1520 seconds I'm guessing Ok Well can we take this up after the break absolutely we can absolutely say it was the point of this is Dr advantage from the University of British Columbia and we'll be back with more of our conversation on time travel here's Paul McCartney little time travel machine of his own called The Flaming Pie right here on coast to coast am. a southbound alternating lane closures overnight there until Richards Boulevard the I 5 northbound your believe part of paving project down at least one lane there just before Airport Boulevard to about a mile after airport next to Port a 10 o'clock from the West Haven solar traffic center News Radio k f b k 93 point one f.m. 1530 am. It's going to be clear cool might expect temperatures to be in the mid to low fifty's for your Monday morning and then we're going to be warming into the mid to low eighty's through the afternoon with plenty of sunshine it will keep the sunshine through Tuesday with temperatures peaking near 90 degrees and beyond that we will see some cooling I'm case here with you meteorologist or for Dorna news radio became. I'm Carolyn Byrnes News Radio p.k. Our top story the Sacramento County Public Health Department is investigating several cases of botulism in Walnut Grove officials say the 5 cases are linked to prepared food bought at the Valley Oak food and fuel gas station on River Road Oculus and symptoms can include blurred vision slurred speech and difficulty breathing anyone with the symptoms who may have bought food at that gas station from April 23rd through today should immediately see a doctor congratulations are beginning to pour in for newly elected French President Emanuel macron President Trump tweeted his congratulations to macron for his quote big when as the next president of France and the Cavaliers became the 1st team to advance to the n.b.a. Conference Finals when they defeated the Raptors 109102 in Toronto to complete a 4 game sweep Cleveland awaits the winner of the Celtics and wizards matchup which is now tied to after the Wizards won game 4121 to 102 I'm Carolyn Byrnes Newsradio cave b.k. 93 point one f.m. And 1530 am the classic locker in the reverse it. I think the great. Deal of the morning. It just jel I Bob Carson with the discovery 5 new advances in science and engineering from the National Science Foundation you're in for a checkup of your valves manifold rotors and pumps not your mechanic but your doctor implantable micro medical devices of just taking a big leap forward thanks to a research team of Columbia University Engineering most current implantable devices have static components rather than moving parts the Columbia team developed a technique that lets them stack soft biocompatible hydrogen all the Tiriel in layers to create fully functional 3 dimensional micro machines with working gears levers and other mechanical parts they're called imams implantable micro electro mechanical systems the team is now modeled and demonstrated an internal drug delivery system to treat bone cancer in mice the device was implanted adjacent to the cancer and required only 110th of the usual dose of chemo meds to be effective m m show promise for applications ranging from pacemakers to sensors to soft miniature robots that communicate wirelessly from within implantable micro electro mechanical systems I guess it's the difference from me being in therapy to the therapy being in me the discovery file scuppers projects with federal funding from the government's National Science Foundation learn more and s f dot gov. I Heart Radio goes one on one with Adam family's life talking about playing shows Welcome back Dr Ben Tippett stays with us from the University of British Columbia theoretical physicist and we are delving into one of my favorite topics and I'm sure one of yours to time travel and he has worked out the math and he says theoretically time travel to the past is possible is it likely well about as likely as a snake being. A snake attending Harvard I think he used and we'll get back to that conversation a moment Terrilyn will also open up the phone lines at the top of the hour questions and comments for Dr Tippett on time travel. Fukushima Of course the anniversary did we just passed the anniversary I believe was a bin for 5 years hard to believe anyway a lot of people obviously are still very concerned about that and rightly so however. The colas evangelists who at the Norwegian Institute for air research says we don't need to worry his team has conducted the 1st global survey of radiation exposure caused by the meltdown of the 3 nuclear reactors at the Fukushima nuclear plant in Japan after a tsunami struck back in 2011 it's been 6 years my apologies Evangelos team has calculated the approximate exposure of everyone on earth to 2 radioactive isotopes of cesium using all the data available so far to radioactive isotopes of cesium most of this came from the Comprehensive Test Ban Treaty Organization which monitors radiation in the environment using a global network of measuring stations quote more than 80 percent of the radiation was deposited in the oceans and pools so I think the global population got the least exposure evangelists told the annual meeting of the European geoscience Union in Vienna he also estimated the dose that most individuals receive to be point 01. Milli c. Avert milli sieverts what I found was that we got an extra x. Ray each says evangelise So it's like we each got an extra dental x. Ray each That's his estimation of the the threat of Fukushima well take that for what you will I don't know I am I have to say personally I'm a little skeptical I think Fukushima. I don't think we know the whole story yet however. That's the story that Nicholas evangelistic ng with from the Norwegian Institute for air research I just a reminder that a subscription to the coast insiders club is a great value for fans of the show and also makes a terrific gift for around $0.15 a day you get over $800.00 past coast to coast shows for immediate download high quality live broadcast podcasts automatic downloads of current shows via i Tunes or our Android and i Phone apps as well as access to our twice monthly live chat sessions back with more of our conversation with Dr Ben Tippett theoretical physicist time travel when coast to coast continues right after this. 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And a welcome back to coast to coast am Richard Sarat sitting in the air chair here coming to you live from coast to runnable Philly talk radio am 640 say hello on Twitter at Richard Serra at s. Y. Our. A quick shout out before we get back to Dr Ben Tippett And time travel shout out to 2 young ladies making their way up the mountains in the southern Greece for some morning coffee yogurt and honey at the a token restaurant Hello yes who all right then can you travel back would is it mathematically hospitable to have to travel back to a specific time or would it just be sort of. You know you take what you can get basically Or can you could you isolate a priest a particular date and travel back to that date. Oh that's an interesting question we mentioned earlier that the thing about time travel is that mathematically it's possible but if it's going to happen among other things you need you need to build this weird space time that takes you back but once you get there you can't change history you can affect history in a way that it's already being affected right so if let's say we could build my heart of spacetime geometry curving us backwards in time propelling us back into the past yeah my geometry the one we wrote about in the paper is a circle in time because a circle is well it's simple but there are mathematical methods to use this model to build more complicated ones that start and at any point so to answer your question yes you can use it to go to any point in the past however if you weren't already there mucking around with things then you probably can't take that ride. That's the best way to describe this. It's like imagine that all of history is a tapestry Ok right and you your your presence your life time is a thread in this tapestry Ok now all the other threads are going up up the tapestry because that's the direction of time you're allowed to go backwards in time according to a theory of general relativity you're allowed somehow in some circumstances to. Twist the direction that your thread lives on the top 3 bending it backwards in time moving it back to some time in the far past ancient Greece or wherever muck about with things but then if you were to take a step back you would have seen that that thread has always. Traced a big wide oval shape back into the past you can't make the thread do anything that it never did on the tapestry before. In other words. You can't you can't change the past if you indeed did go back and muss with things then maybe it's your destiny to do it but aside from that I don't know it's kind of a complicated predestination thing that we're arguing about here and whether or not it's possible because mathematically sure you can use this type of exotic spacetime geometry to transport you back anywhere you want to go the problem is were is there some historical record of you being there did you drop issue back there that some archaeologists are going to dig up in a couple years time Reisa look at the Teweles been worn down I just bought it yesterday right Ok that's the case certainly go back in time what you want if that's not the case. There's a pretty strong argument that you never made the journey Oh boy. We're doing some mental gymnastics here are doing mental gymnastics so again I go back to a professor mallet and he one of the stumbling blocks was that you couldn't travel back. In time previous to the date that you actually turned on the time machine so if you turn on the Time Machine today in 50 years the furthest in the past people could travel back would be May 8th 2017 What are your thoughts on that . That is a big distinction between the types of Time Machine the way we've conceived of time travel the reason I wanted to publish this paper you asked how it was received and the short answer is it was widely ignored by my colleagues but I want to get to that in a 2nd oh dear the trick to building this is that I wanted to in the past. Other physicists have come up with. Ways to Use space time curvature the tram sporran a person into their own past. It's not it's it's not rare there's 5 or 6 I can think of different methods for doing so but all of them involve us saying well you can't really there's something big out in space that has a lot of gravitational pull to it and it's behaving in such and such a way maybe it's rotating maybe it's packed with weird exotic matter that's causing spacetime to curve in a weird way but if I make it to that big system out in space and then I travel around it in such and such a way I can end up in my own past and the time machine you were just referencing is of that sort the time machine that I'm conceiving of is one where it's just a box it's just a box that travels back in time. As opposed to a big weird thing out in space that you have to make the starts spinning and then once you get it up to speed you can use it to travel back but only in as far back as the back date where you turn it on right right mind let you travel between any 2 points but you've got to lay kind of the railroad tracks I mean need it's the there has to be the the the time machine leaves a trail it doesn't disappear between when you start off on your journey and when it ends it's always somewhere and so if there isn't a history of the other blocks the one where you're going backwards in time and the other version of the box right if that version of the box isn't sticking around for all the thousands of years you know if people haven't been seeing the strange box with a person inside it just waiting to get off where you know time I think they look in the window at times and going back to them and there's a wrestling pulling cream out of their coffee Yes that's right for 2000 years then you're probably not going to be able to use it so in that way yeah there has to this object has to be. In the universe when you start inside and when you get off but it's a little bit different than these other ones where you started off and then you can use it kind of as a water slide back in time. It's it's it's a challenge talking about it isn't it it certainly is this is a very it's a very mathematical field and it's also a field that lends itself very strongly to drawing pictures. Yes yes absolutely I mean. Yes No No No And you doing a great job at explaining I particularly enjoyed the breakfast analogy. What what are gravitational waves and do they have anything to do with the possibility of time travel to they enter into this at all or gravitational waves are lovely Oh I love them so much. The short answer is probably not the long answer is will have to do a calculation but let me let me explain. Gravitational waves are. There perturbations in space time I'll get to what I mean by that in a 2nd but they travel like a wave through through space so they just move outwards like a light wave or a sound wave would in in the air right pass through us. They can carry a ton of energy but they have very little effect on the matter in the universe so so the long the short of it is you can't do generate a time machine with that I think I'm going to have to talk about space time curvature at this point if you'll allow me to everybody please do Ok so. The deal with general relativity is it talks about intervals the whole thing is obsessed with intervals and by intervals I mean intervals of time how long a 2nd takes to pass and I travel the space how far away another object is. Got it from an old school classical physics these intervals. Were or were. Didn't depend they were they were foundational they were they were fundamental they can't change right so if there's a rock and it's 30 meters away from you it's always going to be thirty's wait metres away from you and if it moves so it increases to 40 meters away from you it means that something is moving the rocks moving where you're moving Ok got it and steins theory the distance intervals and the time intervals are dynamic quantities and by that I mean they change Ok so what you can have in Einstein's theory is that rock that's 30 meters away from you it's sitting still and you in your chair are sitting still but the distance between you and that rock might change it might go from 30 meters to 20 meters or Michael to 30 meters to 40 meters we're right time it will the same thing we used to think the time interval didn't change one second was one second was one second but in Einstein's framework what happens is because of curvature in space time you can have one second on earth is equivalent to 2 seconds on some faraway distant world or it's equal to you know point 5 seconds if you're up close to a black hole it's a complicated business that has to do with but essentially essentially. The manifestation of this curvature is that the distances between things this distance in time intervals they're dynamic. So if a gravitational wave passes through you what's going to happen is the distance intervals are going to wave it's going to go that rock to 30 meters away from you it'll suddenly be 29 meters away from you and then go back to 30 and then be 31 meters away for you and go back to 30 that distance interval it's going to change periodically as the wave passes through you now it's not meters it's it's like it's a tiny tiny tiny tiny tiny tiny tiny amount of gravitational waves have almost no effect on distances that's why it was so marvelous last year when the Lego collaboration in the United States detected gravitational waves that were produced by 2 black holes colliding billions and billions of years away but is so amazing so they're very much part of Einstein's universe they're very much a phenomenon that Einstein's universe predicted but boy measuring them is a real real difficulty thing I think I think in terms of distance changes the argument was like if a gravitational wave passes through us the distance between us and Alpha Centauri will go back and forth will change on the order of the width of a human hair. Yet that that illustrated beautifully. Undetectible right but this is interesting we're talking about curvature and so the deal is that different types of material cause different types of curvature. Right Ok some materials because well I mean if you really crazy things you get gravitational waves but ordinary materials cause because gravity what we call gravity in Einstein's framework is the effect of this space time curvature so the whole picture is you can have the sun and the sun is generating a gravitational field and in the old Newtonian framework we said that there was a rope an imaginary invisible rope between the sun and the earth and they were pulling each other together and that's what caused the earth to swing in a big circle like a hammer thrower with a hammer you know in the Olympics spinning around fascinating what Einstein said is No it's not like a hammer thrower with a rope it's more like a kid on a skateboard Now keep in mind Einstein didn't say it's like a kid on a skateboard I'm saying it's like you get us get bored because Giffords didn't exist right right imagine a skate park Ok if you were stood on a skateboard it's actually pretty difficult to make a skateboard veer to the left or the right but if you watch kids in a skate park they're turning quite sharply they'll make 90 degree turns on the make u. Turns and the way they do that is they're banking off the curvature in the skate park the skating around their roller skating around escape boarding around on the inside of a big rounded pit and so when they push off the walls the walls will cause them to bank and go into a kind of curved trajectory and so what Einstein's arguing is it's the curvature of spacetime that's causing the planets to go in there circular Well loops or it'll trajectories Ok so the planets are banking off the curvature generated by the sun and here's the fund that different types of material cause different types of curvature. Normal material the type of material we're all used to the type of material or pens and microphones and computers are built out of our hands are built of regular magick even photons they cause gravitational attraction because things to fall together they tell us a certain type of great curvature that we so see it with gravitational attraction so the reason I say that math that time travel is mathematically possible but not actually all that probable has to do with the type of curvature required to do it. Build mathematically I built a mathematical model I came up with an equation describing the curvature required to go backwards in time in this big circle and the curvature required to bend time the direction of time into a circle and then I asked myself well I didn't ask myself I asked Einstein's equation what kind of curvature what kind of material do we need to make this type of curvature and the equation tells us that this type of curvature is generated by a type of material we've never seen it's not gravitationally attractive so there's a word for it in my field and it's called exotic matter Ok Zadok because we have never seen it in our universe you take your telescope all of the matter all of the light we look at everything we can detect and interact with doesn't generate the type of coverage we need to go back in time. It doesn't mean that it doesn't exist but what it means is we've never seen it and so I have no idea where we can find it I am not going to bet that we are going to find it anytime soon so long story short mathematically possible but we know exactly what it will take to build one of these time machines and the short answer is we don't have the stuff to build it. Is it. The the exotic matter that you talk about we talking about the at the energy Rick is here and is that energy that's required to bend space time space or. I mean how would you say if it's not quite a matter of what type of energy it's a man story it's not it's not a matter of quantity of energy it's not that we just don't have enough energy it's the type of energy. We're talking about things that have weird pressure energy relationships that we've never seen before we're talking about matter that has negative energy that we're talking about Pepcid matter that might travel faster than the speed of light is it legal that sounds in regular in high school relativity when they're teaching people relativity they say nothing can travel faster than the speed of way or nothing can the other immutable law of nature is I have to take a break so will work take your time our. Mary Queen he learns try me on the other side more of our conversation on time travel here on coast to coast am. Always mutual. 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