Is Time Travel Through Wormholes Actually Possible?

Summary

This fascinating transcript delves into the concept of time travel through wormholes, exploring its theoretical plausibility based on Einsteinian physics. The discussion originated from a conversation with Carl Sagan regarding his novel 'Contact.' It covers the intriguing paradox of aging differently through a wormhole and Stephen Hawking's time travel prevention conjecture. It further examines modern physics' approach to vacuum fluctuations and exotic matter, key elements in potentially manipulating wormholes to become time machines. Despite conceptual breakthroughs, challenges remain due to quantum gravity and the need for exotic matter to hold wormholes open.

Highlights

• Discover how wormholes could, theoretically, allow you to travel back in time and meet your younger self! 🚀
• Stephen Hawking proposed that any time machine initiated may self-destruct due to vacuum fluctuations - a cosmic safety feature! 💥
• Modern physics explores manipulating vacuum fluctuations like in the Casimir effect, revealing the bizarre world of exotic matter. 💡
• Even if wormholes can be held open with exotic matter, the unresolved mysteries of quantum gravity loom large. 🌟

Key Takeaways

• Wormholes create a fascinating paradox: travel through them, and you might meet your younger self! 🤯
• Stephen Hawking theorized that time machines may self-destruct to protect the universe's timeline. 🚀
• Quantum fluctuations might hold the key to time travel, but they also pose a runaway risk! ⚛️
• The Casimir effect shows that manipulating vacuum fluctuations creates 'negative energy,' essential for keeping wormholes open. 🌌
• Despite the theory, practical time travel remains out of reach due to limitations in understanding quantum gravity. 🕰️

Overview

In an exploration of theoretical physics, this transcript unpacks the captivating possibility of time travel via wormholes, triggered by conversations between renowned physicists and inspired by science fiction narratives like Carl Sagan's 'Contact'. It investigates the complex paradoxes wormholes might introduce, such as witnessing different aging processes for those at each end of the wormhole.

The discussion dives into Stephen Hawking's conjectures on time travel, suggesting that while wormholes could theoretically enable journeying to the past, they may also self-destruct upon activation due to intrinsic cosmic safeguards, thus maintaining the universe's historical continuity. This highlights an engaging intersection between theoretical physics and the preservation of causality.

Moreover, the debate extends into modern physics' experiments with vacuum fluctuations, such as those in the Casimir effect, indicating potential controls over these phenomena through exotic matter. Despite theoretical advances, practical applications remain hindered by gaps in understanding quantum gravity, though the field continues to evolve, looking to unlock further secrets of the universe.

Chapters

• 00:00 - 00:30: Introduction to Time Travel and Wormholes In this chapter, the concept of using wormholes to travel back in time is introduced. The speaker questions whether such a feat is mathematically and physically possible based on Einsteinian physics. They ponder the implications of interacting with a younger version of oneself and what it might mean for one's existence in the originating timeline. The chapter hints at Stephen Hawking's contributions to time travel discussions.
• 00:30 - 01:00: Carl Sean and the Concept of Wormholes The chapter discusses a concept in physics related to wormholes, inspired by a conversation with Carl Sean. This conversation sparked an interest and deeper consideration of wormholes, indicating a collaboration of ideas while working on the novel 'Contact.'
• 01:00 - 01:30: Carol's Journey and Age Difference In this chapter, a scenario involving wormholes is discussed, particularly focusing on the implications of time dilation. The narrator suggests that by giving one end of a wormhole to his wife Carol Lee, who travels with it at high speed on a round trip through space, a significant age difference can occur between them. Although 50 years pass for the husband on Earth, only a year passes for Carol during her space journey.
• 01:30 - 02:00: Wormholes as Time Machines This chapter explores the concept of wormholes as potential time machines. It illustrates this with an example where two people on either side of a wormhole age at different rates depending on their reference point. When viewed through the wormhole, they age at the same rate, but when viewed from the outside universe, one person appears to age significantly more—a scenario depicting the relativistic effects of time dilation in the context of wormholes.
• 02:00 - 02:30: Self-Destruction and Vacuum Fluctuations The chapter titled 'Self-Destruction and Vacuum Fluctuations' explores the concept of a wormhole turning into a time machine. It discusses the possibility of traveling through one mouth of the wormhole and meeting one's younger self. However, Stephen Hawking proposed that there must be an unknown principle or conjecture that would prevent this type of time travel, implying that the universe would not permit such paradoxes. The chapter hints at a dialogue involving friends and deeper discussions on this theoretical topic.
• 02:30 - 03:00: Quantum Gravity and Wormhole Stability In the chapter titled 'Quantum Gravity and Wormhole Stability,' a physicist from the University of Chicago discusses the importance of collaboration in scientific work, highlighting how colleagues can help identify mistakes and provide guidance. The focus of the chapter involves a hypothetical situation where a time machine might self-destruct upon activation. The physicist initially doesn't understand why this might happen but is encouraged to perform calculations to explore the concept further, thus illustrating the collaborative nature of physics research.
• 03:00 - 03:30: Hawking's Cosmic Censorship Conjecture This chapter discusses the implications of Hawking's Cosmic Censorship Conjecture, with a focus on the possibility of time travel and its effects. It suggests that, theoretically, if time travel were possible through a wormhole, vacuum fluctuations could occur, leading to a doubling of these fluctuations as they enter and exit the wormhole. This scenario highlights potential paradoxes and challenges in theoretical physics concerning space-time structures.
• 03:30 - 04:00: Quantum Precision Measurement and LIGO The chapter discusses the concept of runaway feedback loops, particularly in the context of quantum precision measurement. It describes how feedback between a microphone and speaker can exponentially increase, and how this concept translates into quantum mechanics. The speaker reflects on a specific quantum mechanical calculation involving runaway feedback, in collaboration with a Korean postdoc, San Juan Kim.
• 04:00 - 04:30: Carl Sean's Novel 'Contact' and Wormholes The chapter discusses the aspiration of becoming a movie director and the motivation to innovate and achieve seemingly impossible tasks, akin to 'pulling a rabbit out of a hat.' It highlights a significant scientific discovery attributed primarily to Stephen Hawking and a student. Despite the complexity of the discovery, it is suggested that Stephen Hawking's genius allowed him to conceptualize it mentally, demonstrating his extraordinary capabilities. The chapter mentions collaboration with someone named Stevenson in this scientific pursuit. Overall, the chapter reflects on ambition, innovation, and the remarkable intellectual prowess of Stephen Hawking.
• 04:30 - 05:00: Exotic Matter and Wormhole Stability The chapter discusses the stability of wormholes in the context of using exotic matter. The narrative unfolds through a conversation between the narrator and Steven, who exchange ideas via email and phone calls. Initially, the narrator is of the belief that if a time machine is designed correctly, the resultant explosion wouldn’t be strong enough to destroy a wormhole. However, Steven, through detailed calculations, proved the narrator wrong. The chapter ends with both parties eventually agreeing on a particular aspect of wormhole stability.
• 05:00 - 05:30: Virtual Particles and Vacuum Fluctuations The chapter explores the concept of how quantum gravity plays a crucial role in understanding the fate of a time machine. It discusses the implications of quantum gravity on the stability and functionality of a time machine, raising questions about its potential self-destruction due to fundamental laws that are not yet fully comprehended. Additionally, the chapter introduces the Hawking's cosmic censorship conjecture, which proposes that nature hides singularities from the universe, maintaining a kind of cosmic censorship.
• 05:30 - 06:00: The Casemir Effect The chapter discusses the limitations of quantum gravity laws in preserving wormholes and time machines. It mentions that any attempt to use such devices will lead to their destruction due to vacuum fluctuations, thus safeguarding the universe for historians, as proposed by Hawking. This concept is likened to the ultraviolet catastrophe in physics.

Is Time Travel Through Wormholes Actually Possible? Transcription

• 00:00 - 00:30 what's this i hear that you can use a wormhole to travel backwards in time does the math check out does the Einsteinian physics check out and does that mean I will just show up a younger version of myself and shake my own hand is that what you mean by that or do I no longer exist in the time that I left for my younger version of myself to see that and wasn't there I didn't Hawking put forth a time
• 00:30 - 01:00 travel prevention conjecture or something was what what's going on there so this is all an outgrowth of my phone conversation with Carl Sean uh when he was uh working on the novel for Contact where uh he triggered me to start thinking about wormholes and then having started to think about wormholes
• 01:00 - 01:30 it became pretty obvious to me rather quickly that if uh I give my wife Carol Lee one mouth of a wormhole and she carries it at high speed in a rocket ship out into space and then back and I keep the other worm mouth at home uh and uh if she she sees me age by 50 years back on Earth well she ages only one year going out and coming back but if we
• 01:30 - 02:00 look through the wormhole at each other uh we see each other aging at the same rate just imagine uh we hold hands and we look at each other's wrist watches they're it's ticking away at the same rate so through the worm through the uh wormhole we paged at the same rate we're the same age but uh looking throughout outward through outside the wormhole through a normal universe she's aged one year and I've aged 50
• 02:00 - 02:30 years something weird has happened the wormhole has become a time machine if I just go over and go into her mouth wormhole mouth and come out I'll meet my younger self okay and now Hawkings said "This is no we're not going to allow this there's some conjecture yet to be discovered that'll tell you you can't do that." Well so no the story we get there you're going too fast i'm going too fast sorry so so I then I talked to friends at the
• 02:30 - 03:00 University of Chicago physics it's crucial to talk to friends they tell you where you're all wet they tell you when you've made a mistake they straighten you out and they pointed out to me that uh it might be that when the time machine is turned on it'll self-destruct basically they said I said "I don't understand." They said "Go do a calculation." So I went and did a calculation and the issue is and they had guessed in the basically that's
• 03:00 - 03:30 oversimplified but they Bob Gro and Robert Wald at Chicago uh anyway it turns out that uh at the moment that you can first time travel the first thing that goes through can be vacuum fluctuations of light say that enter her mouth of the wormhole come out of my mouth and go back and arrive back at the her mouth at the very moment they started out now you have twice as much at the same place in space and time so
• 03:30 - 04:00 this is a runaway so it's a runaway and so they you now have twice as much and then it goes around again now you have four times as much goes around again so this runaway uh builds up the feedback between a microphone and a speaker precisely and it'll just runs away it just runs away and it runs away and and this runaway shows up in the quantum mechanical calculation that that I did you're buming me out together with San Juan Kim a Korean posttock of mine okay
• 04:00 - 04:30 okay I want to be a movie director and say go hip go home and figure out how to do this give me another pull another rabbit out of the hat here well anyway we discovered this Stephen I think and one of his Stephen Hawking uh and a student of his I think had more or less the same discovery at the same time except Stephen probably just did it all in his head just that's the way Stephen is anyway so uh then Stevenson and I
• 04:30 - 05:00 started corresponding about it by email and talking on the phone about it and so forth it appeared to me looking at at the details of the calculation that uh in fact the explosion if I designed the time machine just right the details of the explos explosion would not be strong enough to destroy the wormhole uh and Steven then showed me that I was wrong and we argued back and forth for a while finally we've came to agree that the
• 05:00 - 05:30 explosion becomes strong enough that quantum gravity enters in and then holds the answer tightly in its grip and so we won't know whether the time machine self-destructs until we understand the laws of quantum gravity let me be fun and obscure here but then we come to the Hawkins cosmic censorship conjecture that's what it's called yeah he the conjecture that in fact uh in the end
• 05:30 - 06:00 the laws of quantum gravity won't save the day the wormhole will be destroyed and any time machine that any advanced civilization makes will be destroyed when they try to turn it on by these vacuum fluctuations uh and thereby as Hawkings says keeping the universe safe for historians of all species it reminds me of the ultraviolet catastrophe mhm where you run the
• 06:00 - 06:30 calculation this is going to blow up how does this even work and then out comes the discovery of the quantum which saves the day mhm right and this is could be a calculation waiting for another branch of physics to open or or another progress in the known branches of physics to resolve the LIGO team has has uh perfected a technique called quantum precision measurement which is based on manipulating vacuum fluctuations
• 06:30 - 07:00 uh in order to circumvent the uncertainty principle and so this business of manipulating vacuum fluctuations is something we do in modern physics if memory serves Carl Sean came up to you and said "For contact I want to go far distances quickly how am I going to do it can you cook up a wormhole for me?" Carl phoned me uh in well back in the 80s um when he's
• 07:00 - 07:30 writing the novel cuz obviously the novel predated the movie that's right and he said that he wanted uh that he has written he'd already written this the book the novel it was already in page proofs and he said I've got this novel it's in page proof the publisher is not going to be happy if I change it but I really need some help to see what the truth is and then we'll figure out how to deal with this and uh he said
• 07:30 - 08:00 that I have my heroin traveling through a black hole to get to the star of Vega and I said that's rather dangerous there's a singularity in there okay there's a singularity in there and you can't get through get to to the star of Vega so what you actually need is a wormhole uh but there is an issue the wormholes implode they collapse so quick that nothing can get through but I'll
• 08:00 - 08:30 see if I can figure out how to how to hold a wormhole open just for you Carl and so and so I was go I was going with it's like rent a physicist it's like whatever your needs are so I so I was getting in a car that that morning to ride uh with my uh former wife to our daughter's graduation up at Santa Cruz uh and so Lind Linda was said "I'll
• 08:30 - 09:00 drive and you calculate." Okay so she drove and I calculated i fiddled around and then it became fairly obvious turns out somebody other some other physicist figured this out sooner but that's the usual thing with me i I figure it out then then I go see did people know this before or not so So anyway I figured out that uh you if you had what I like to call exotic matter that repels gravitationally and
• 09:00 - 09:30 you put it inside the throat of a wormhole that can hold the wormhole open it'll be like pushing it outward that's right it basically repels the the walls of the wormhole to hold them open and it turns out that that that will do it but you have to have uh you have to have enough exotic matter to hold the wormhole open and I deduced a formula for for how much you had to have bas and it basically says the
• 09:30 - 10:00 following uh if you move through the wormhole but the record show he's about to describe how to make a wormhole no no only how to hold it only how much exotic matter you have to hold it open but that sounds like a recipe to me so So you you travel through the wormhole as close to the speed of light as you possibly can just close to the speed of light and you uh c you add up all the the energy
• 10:00 - 10:30 density all the way through the wormhole of stuff that's in the wormhole the net has to be negative and then you hold the wormhole open so it basically means you've got more negative energy in there than positive energy because we have nothing known as exotic matter oh yes we do what yeah and so they Oh is is this in your basement is what what do you mean oh what what what do you mean oh yes we do what what okay what what is our exotic matter that
• 10:30 - 11:00 would fulfill this purpose so so if you Should we turn off the camera now are are the is the government going to show up on your in your driveway okay go well I I learned about this from Yakov Bisovich Zaldovich in Moscow zaldovich zaldovich was one of the inventors of the Russian hydrogen bomb okay and I learned this from him all right okay he was really brilliant i learned about about vacuum fluctuations and how important they can be and what
• 11:00 - 11:30 how powerful it can be if you can manipulate them and uh so and so if you take a box and you remove everything you that can possibly re be removed from the box you're left in the end with tiny fluctuations of everything that cost possibly could have been in the box so electric fields you have fluctuating electric fields fluctuating magnetic
• 11:30 - 12:00 fields fluctuating protons electrons fluctuating neotoy the grass tyson's so this this creates a form of pressure inside the box well so the next there's vanishing pressure and now vanishing energy due to renormalization that's a that's a nasty word in physics but the uh the uh well me we can you can measure energy
• 12:00 - 12:30 by whether it produces gravity or not and uh although these fluctuations that are there it you can think of them as particles say particles of light flashing in and out of existence randomly so why isn't this not the virtual particles that people speak of so it's virtual particles it is that okay we we've spoken about those on our show before okay so you have virtual green in fact so you have virtual particles uh in the vacuum popping in
• 12:30 - 13:00 and out of existence popping and and and you can't stop it you can't prevent it however you can take fluctuations from one region and borrow them and put them in another adjacent region for a little while or if you put an electrically conducting uh sheet say a sheet of of of superc conducting metal here then that will suppress the
• 13:00 - 13:30 fluctuating electric fields parallel to the metal because they would create an infinite current flowing in that metal and that would uh that that would wipe out the the electric field parallel to the metal and so uh is that an element of the Casemir effect yes that's the case effect it is yeah where you have two parallel plates evacuated between them that's right and there's a point where they actually feel a whole other force contracting and so what that force really is is uh in the region between
• 13:30 - 14:00 them uh the vacuum fluctuations are suppressed and so you have negative energy in between that energ negative energy is sucking them together and you have you have you and they can do work on you if you you're holding on to these plates uh and they attract each other put energy to resist you put you put energy in as they go as they go together they do work on you the electric electromagnetic field between two plates
• 14:00 - 14:30 in the kasmir effect uh is exotic okay and so so you have this in your basement is what you're telling me yeah well I don't have it in my basement