Sean Carroll: The Paradoxes of Time Travel
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- เผยแพร่เมื่อ 2 เม.ย. 2018
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Science fiction has introduced us all to the idea of traveling into the past - but is it really possible?
Sean Carroll talks bout how time travel would possibly work in the context of Einstein’s theory of general relativity, including the hypothetical idea of wormholes connecting distant regions of space. Dr. Carroll also explores the logical structure of time travel, and what it implies about predestination and free will. In the end, time travel is probably not possible, but by taking the idea seriously we help understand how the universe works.
Dr. Carroll is a Senior Research Associate in Physics at the California Institute of Technology. His most recent book is “From Eternity to Here: The Quest for the Ultimate Theory of Time”, a popular book on cosmology and the arrow of time. He is a contributor to the blog Cosmic Variance.
From a 2010 lecture at Linda Hall Library. - แนวปฏิบัติและการใช้ชีวิต
I remember watching this back in 2023
Your Mom.
Lol
Me too , i already got an answer before watching the show.
I'm still going to listen, just it cas he says something i forgot.
But by watching it youll change the future.
Good one
repawnd... lol... rich real rich ha ha...I love it.
Skip to 3:25
Thank you.
Great. It made me travel back in time
Not every hero wears a cape
thank you.
Thanks man, I was skipping 10 secs at a time hoping to get there.
What do we want?
Time travel!
When do we want it?
It's irrelevant.
HAHAHAHA
🤣🤣🤣
Highly under rated comment.
When do we want it?
Now
What do we want?
Time travel!
Bravo
intro over @3:30 / lecture actually starts @3:30. I love how he talks. makes it very understandable and easy to grasp!
+rep
Well that depends on how you quantify time…
thank you for getting rid of the adds that are previously mentioned.
Everyone be sure to turn your ad blocker on for this video.
or find a yt premium friend ;)
@@charlesmarshall7045 shame on your friend encouraging youtube
shame shame shame!!!
That's not cool. We should be willing to support channels like this. But me personally, definitely turning adblocker on for sure.
What on Earth are these "ads" you people keep talking about?
Money grabbers!
The reason why TIME is so popular a noun on the internet is because most times we use time we aren't referring to the concept of TIME, but rather we use it to indicate an event or occurrence. Sometimes it's specific, other times it isn't, but each time we use time will add to the total number of times that Dr Carroll refers to.
It's about time someone placed a well timed comment about how much time we devote to the concept of time.
In other words if we go back in time to change something, we make it what it always was.
no, if we go back and change something in the past that creates an "alternate" timeline. The timeline we came from still stays the same.
And do all of the Michael J Fox movies exist about something so trivial in the alternate timeline?
Mike Smith y
Rick Raftus and yet both timelines simultaneously existed to begin with. Either way what does it matter. Everyone is you anyway.
Another excellent talk by Dr. Carroll. He is one of several respected scientists who have the ability to inform the general public of the wonders of science. We need more such people.
Looking forward to his podcast
Dr10Jeeps try deep sky video channel,they have great professors talking about all sorts of space and physics topics.To me one of the best is Ed Copeland
@@michaelfarrell4824 his podcast is fantastic if you haven't started listening to it yet
WELL SAID MATE.
We can't go into past can we go into future suppose I sit in the spacecraft which go 90 percentage light speed when I come to earth my 1 year equal to 100 year on earth ( calcution may be wrong). That mean I can live in the future I can see the future that my younger brother can't see by living on earth is that passible
Love this man. He can explain the most arcane stuff to [relative] toddlers like us. That's a rare skill...
Hey speak for yourself buddy now wheres my Binkie it`s nap time
Like you. Others like me have no problem following along & understanding these things. You probably have a learning disability pal… I’d get that checked out if I were you…
There must be at least two versions for Sean Carroll. I don't believe that a man can be such a brilliant communicator, such a deep thinker on matters of life and death, and still have the time to do something else for a living. On top of that, what he does for a living is fundamental physics research, and he does it at top levels. Does the second Sean Carroll come from the future?
No, the other one is an evo-devo biologist. :)
No.
@@macysondheim Yes.
@@minirock000 No
@@macysondheim But there is another Sean Carroll.
This video has the best, most succinct explanation of light cones I've heard yet, and I've been reading about and watching this kind of stuff for decades.
I just love that the vid is in 4:3 very time travelish!
A few more ads might make this more enjoyable.
ad-block is clutch man, get on that.
lol
What are ads? ADP for me.
No ad block on iPhone
Adblock in App store for iPone,
Seen in first person the first time at the old brownstone in pa. Took a pic and we were escorted away. Came up to me after his lecture as we waited outside. Took our crowd to his afterparty and discussed slowstone and off topics for hours. A great guy.
Dr Carroll is such a good speaker and they're always interesting.
He’s*
Sean Carroll is a wonderful science communicator. I'd have loved to sit in on one of his lectures back in my uni days....
Very well explained, was waiting for someone to explain,especially the light cone. Finally came from him.
...WoW,,, I just watched the movie Interstellar, completely fell in love with it as it dealt with black holes, time travel, worm-holes, love and parent relationships all in one. I just loved every minute of that movie and it really uplifted me! I turned on TH-cam literally immediately after the movie and this video was at the top of the list of suggestions,,,,, WoW...
The best thing is... There are times I can follow and more often lost. Yet, the world thing makes me captive all the way into the future and back. For better or worst. Thanks Dr Sean. Keep up with the good work. Stay safe and healthy. We welcome you to enrich the present at least.
From Hker worldwide
36:53 - I'm a bit shocked that Sean, of all people, didn't correctly explain how GPS works. Your GPS receiver does NOT transmit ANY kind of signal, it is _receive only._ The internal clock that each satellite carries are all perfectly synchronized with each other and each satellite regularly transmits an earthbound signal that contains a timestamp of when it was sent. Since orbital machanics can describe the precise position of each satellite at any given moment, each satellite's orbital location is also known. Your GPS receiver determines how far away you are from each individual satellite by noting the time that it took for each signal to reach you. Those individual distances each equate to the radius of an imaginary sphere around each satellite. Since your GPS then "knows" your location MUST be somewhere on the "surface" of each imaginary sphere, it calculates the intersecting points for all the spheres (also known as trilateration). Based upon a few simple rules, the receiver can throw away locations that don't make sense (such as deep inside the planet or out in space) and it will arrive at ONE logical intersection point which will be near the earth's surface and THAT is your location. Using three satellites, the receiver can determine your 2D location (latitude & longitude) on the surface of the planet and with a fourth satellite it can also determine your altitude. It's most certainly time based, but there is NO "back and forth" going on between your GPS radio and the satellites themselves.
Very nice explanation, I've always wondered the exact mechanism!
BluntForceTrau
Just a small footnote to your excellent explanation. Good old Einstein comes into his own when it comes to GPS. His theories dictate that a moving object (relative to you) will experience time passing at a slower rate than you. Normally, on the planet, at the speeds we move around, this time dilation is so small as to be negligible. However, GPS satellites travel at such a speed (relative to us) that the atomic clocks onboard are set to run at around 0.3 ms a day faster than here on earth. If these miniscule clock adjustments had NOT been made, then the intersections calculated by our GPS systems would "drift" by a cumulative amount of 0.3 microlightseconds a day. As light travels at roughly 186,000 miles a second then this "drift" would be in the region of 186/30 (6.2) miles a day. Please don't tear my maths apart (I'm doing this from memory and can't check with my text books - but the theory is correct) but, if Einstein had not postulated his theory of general relativity, then we would have spent billions putting up a GPS system that would have been unusable within an hour of it being switched on. I find it amazing that a theory, put forward in the early part of the 20th century must be taken into account in order that our cars, planes and ships know exactly where they are on the planet. I mean - how neat is that? 😁
@@paulkearnsmusic It's even neater than that. There are 2 different time dilation effects, in different amounts and in different directions. The speed of the satellites makes their clocks run slower due to the effects special relativity, and the altitude of the satellites makes them run faster by a different amount due to the effects of general relativity. The adjustment needed to the clocks on the satellites to make GPS work precisely matches what you get when you add together the effects of SR and GR.
Wait a minute... as I understand your explanation the Satellite must be sending the location to the GPS Receiver constantly I mean it would never stop getting a signal... does not makes more sense to ask for the signal only when needed? just asking... If it asks for a signal when needed instead of receiving it continually then it must send a signal to the satellite which would mean it transmits a signal to the satellite to which the satellite(s) responds with it's location... if it gets the signal without stopping then it is correct it does not need to send a signal to the satellite and would be correct it only receives... or is the satellite sending the location constantly and the GPS Receiver only accessing it when needed... otherwise it would be working continuously without stopping at any time...
Just asking I'm curios about it...
So theoretically, a UFO that controls it's own gravity is essentially a time machine.
Not correct. Everything this idiot is saying is based on assumptions, not provable science.
No actually you are correct Don da vinci
Trevor Jameson , the very nature of science is not about proving things. It is about disproving.
Also, don't be a troll.
@@trevorjameson3213 agreed the problem is science doesnt even know the true speed of light, they only know the 2 way speed of light. all experiments to measure the speed of light has used mirrors or optics. im sure light is slowed down significantly once bounced off a mirror or through a medium. there are even theorys now that postulate that light might instantaneous one way
@@trevorjameson3213 Even Einstein thought blackholes are too fictional and too impossible to be true, even people thought flying humans is too science fictional before the wright brothers. It's not like you are having any ceribral defact, if any mind can't imagine something wholeheartedly, it becomes an impossibility for him. Empirical evidence suggests that every thing that maths has proven and equations have settled, is possible and totally achievable by humans if given enough time.
PS-Lots of love.
This is a wonderful lecture. Thanks for posting it here. Much appreciated.
It's my pleasure 😊
4:28 actually starts his talk.
it almost feels like science is catching up to the comics
It’s more like they use the comics to engineer an understanding of what science has always been capable of and we just need to believe it.
I hope so.
Except that Einstein made his theories over 100 years ago, so it's comics catching up with Einstein.
@@brendanh8193 The foundations of quantum physics were layed but the theory of quantum physics is constantly evolving
Dude is smart its enjoyable to hear him speak. He has good interviews on Joe Rogan show too, I have a couple saved and listen when I need some thought provoking content. Good stuff man 👍
My takeaway is Black Holes ruin everything.
Dude? He’s a theoretical astrophysicists. Show some respect, 🤡.
I struggled to understand these concepts. I think I will take a nap and try again yesterday.
As I'm getting older and moving into the future I find I'm living more in the past. What a tremendous amount of energy it would take just to go back and get a 25 cent burger.
I learned more from watching this video than when I read that book about Time after my cat died and I was looking to find logical ways to find hope, that she's existing in another universe. Very well explained. My only question is the Light Cone itself. What the heck is this light cone thing?
It’s a cone of light.
I have a couple of questions.
When we see images of far off distant galaxies we're told we're seeing those galaxies as they were in the past. How far in the past is relative to their distant from us. If we look at a galaxy that's 100 million light years away, the light has taken 100 million light years to travel to us. Is what we see a snap-shot of what it looked like exactly 100 million light years ago, or is it actually earlier or later. In other words is light affected by time over distance the way a clock for example is affected by speed and distance?
Another variation of the same question; Two people observe two supernovae. The first person is right next to the first supernova, the other super nova is 100 million light years away. The second person is 100 million light years from the nearest, with the second supernova being 200 million light years away. This first person sees both supernovae at the exact same time. (for arguments sake there's a clear path between all of them, and the person stood next to the exploding star is shielded and able to observe such a thing without harm or injury). Because the first person sees both at the same time, did the one standing next to the supernova see that at the exact same time as the light from the distant supernova arrived. And because time alters based on speed, is this reflected in the image of the supernovae? Or does time dilation only affect a person or object if it were able to move at the speed of light (for arguments sake) or close to that speed, but light isn't affected in that way!? (I hope that makes sense).
UPDATE. (to my past self) The person furthest away that saw both supernovae at the same time saw them 50 million light years after the person stood next to the second super nova, who has to have seen the one next him at the same time as the one 50 million light years away! Idiot!!!! Problem solved, lesson learned; don't ask stupid questions online!
Dunno m8
All I know is if you were able to ride on a beam of light from any distance, the time you arrived at any destination would seem to be instantaneous. No time at all.
100millon light year is the time it took for the light to come to us. So yes you see 100million light year in the past.
It takes 8 minutes for a photon to go from the sun to us, so what you see is as the sun now is actually the sun 8 minutes ago.
On relativity, each person see what they see now. Each now is different (relativ). We are at different coordinate. Different point of view.
When litening strikes one mile away i see it at the speed of light, yet i hear it at the speed of sounds. They appear separated by one second.
A person under the lighting hears and see it at the same time.
Light and sounds travel thought different medium, electro magnetic field vs acoustic field.
Yes it is both space but an analogy would be a phone, it is all 0 and 1 but at higher levels you have building blocks, programs and on top apps. 0&1is fast, but your apps run slowly in comparison.
I hope it helps.
Thank you again for your question.
@@aurelienyonrac Yeah I was already aware of the thunder and lightening thing. I've just read through my original post again, and I'll be honest, I'm not sure what I was confused about. The only excuse I can come up with is I had just watched a handful of documentaries/lectures and I think I was overthinking the issue. I wish I could say I had been drinking but I hadn't! The original post seems kind of dumb, but I won't change it because people have replied to it. But thanks for answering the clearly younger dumber version of me!
@@quantumjet253 we are growing. Confusion is part of that process.
Thank you for your feedback.
I absolutely love this topic and thinking about it since my childhood !
My top 3 theories [not very scientific but it serves its purpose]:
***
1. Travel possible, time traveler creates his "personal" new parallel dimension upon changing anything in his past (even just being int he past actually is considered changeging ).
[example: kill parents "nothing" happens to you. After you travel back to the time you came from you are in a "parralel" future where you never existed.
That could explain why we never witnessed time traveling because everytime a person uses such a device he creates his own dimesnion and will be never seen again even at the same timeframe.
***
2. Travel possible, paradox possible which means you would create a real paradox and cause a catastrophic event [maybe like a new big bang OR every matter that ever interacted with the "time paradox contaminated" material within the time span of the timetravel would be "erased from existence" - maybe the cause of some of the giant voids in the universe ^^
***
3. Travel is impossible because time itself doesn't exist and its just a state of matter. The past never is "away" in an arrow behind us we are at the same spot, the spot itself is everchanging so we think there is an arrow [its hard to measure with instruments if they themselves are in that change zone ]
1. Where does he get the energy (and matter) to create a new universe?
2. A paradox is a paradox because it's something that logically can't happen. Not something that is really bad if it happens.
3. OK.
I like to think of time as an expanding bubble, it had a beginning point but no ending point (that we know of), we can't travel back in time but we can ride the event-horizon of time into the future. The past and future don't exist in the same way as the physical dimensions exist. You can't travel into the future (faster than time itself is expanding) because it doesn't exist yet and you can't travel into the past because it doesn't exist anymore.
Time is fascinating. I worked the subway stations for nearly 10 years. From one end of the city to the other. Every so often I would notice the city would be saying that, "Today just flew by" or "The day was just dragging along." How can an entire city, with no interaction with each other until they used the subway, complain about the same time paradox unless it was effected by it? Maybe a time distorted bubble the earth passes through in its revolution around the sun. Maybe random waves of time distortion hitting the earth? Maybe they're given off by the sun. Maybe they're from outside our Terran system and reach us in intervals. ???? "Ti-i-i-ime, is on my side. Yes, it is"
Anyone still watching in 2079?
The year is now 2236 and this video is the start of a way of new thinking. We now have the ability to change tiny pieces of the past which you have hastily call the mendella affect. I can assure you the future is remarkable.
the machine 2236 and they can’t even spell Mandela... I weep for the future.
Robbie Watson so you know were all literally the same person as well huh?
So did we beat the coronavirus?
Addams Riley@ In 2236 the convention of using caps in English had changed and the Mandela (mandella) has also changed. In the future adhering to the rigid Noah Websters version of spelling has been replaced by Benjamin Franklin's view that "a man who cannot spell the same word in more than one way lacks imagination. You are using an anachronism dating back to 2023. 😊
This guy’s voice is John Mulaney if he wasn’t just making jokes about how drunk he used to get and calling himself an old Chinese woman.
Well I guess that is the answer to the Great Filter- any alien civilization that achieves the ability to fiddle with time travel, gets swallowed in a black hole.
Yes! I knew he reminded me of someone and could never think of them. Has been bugging me for some time now. Thank you!
Eric Drye Glad I could help. 2088 is super weird.
What makes this so impressive is that Sean and his 2 brothers used to all be gang members in the neighborhood they grew up in. Through perseverance & hard work he was able to outgrow all the negativity & challenges. God bless America .
17:16
"But nobody has an actual plan for making this happen..."
* rubs hands together and begins to chuckle, then chortle, then snigger, then giggle, then laugh, and finally burst into raucous peels until the whole Skull Island rings with maniacal laughter *
Lockheed skunkworks already been there and done that buddy. You’re about 50 years to late.
6:20: When Sean Carroll fails to mention that all those webpages likely have "time" as part of some ubiquitous text on the internet, such as datetimes for Tweets or time of posting for blogs...
I think this follows his point, which is that we care about “time” a lot. Otherwise we wouldn’t care about the time something was posted and it wouldn’t be displayed.
a bit greedy on the monetization, channel owner!!
especially since he stole the video from the legitimate producer of it
www.lindahall.org/event/paradoxes-time-travel/
Watch without ads.
Really annoying
If you want everything on TH-cam Ad free download and use Firefox with Adblock Plus as an add-on to block all the ads and commercials.
Or just pay 10 bucks for red.
Interstellar by Christopher Nolan. Incredible movie that took the challenge of this man! At 44:46 he starts discussing movies that got time travel right or wrong, the best one yet (literally) is Interstellar.
That Sydney to La t-shirt cracked me up
Determinism vs free will is compatible.
Imagine all possible future outcome already exists. So it is determined. But you are free to experience the one you are interested in. Some of these interest are predetermined and you may be able to change those. Most importantly, you can choose how you experience your path. You are the one saying each thing, place and people is bringing something positive or negative to my experience.
@Phelan ok, all possible versions of the universe already exists simultaneously. All possible variable already exists.
A universe takes no room, it is self contained.
With your attention, your presence, your being, you shift from one version of a universe to an other.
But who are you?
Are you just a peson, or your possession, or your emotions, your thoughts, are you still more? Have you for the limit to yourself? And if you did find a limit, aren't you the one saying it it, and so it is.
Freedom is not found, it is who you are. It takes No effort to be free.
It is a gift
A present
Your presence
Found each present moment.
How does that feel?
Y
@Phelan you seem to know what you are talking about. Tell me more.
@@aurelienyonrac He already told you enough to counter your original point. Balls in your court.
It's not "woohoo," Phelan. Have you heard of the Many Worlds theory? The multiverse? Etc. There are various ideas from the notables in physics that talk about this very idea. Even Einstein talked about the idea of the Past, Present, and Future existing all at once and that our idea that we're "moving through Time" is an illusion created by our limited ability to view the 4th dimension (ie, we're scanning it "line by line," so to speak, rather than seeing it all at once).
Add to that the idea of the MWT or the multiverse or whatever and you quickly end up in a place where ALL possibilities already exist. All pasts, presents, and futures, exist. There is nothing you can do or not do that isn't already done or not done and "time travel" would really be a shift in your local viewpoint rather than an actual change being made (and the idea of "shifting" would be an illusion too, created by your limited view from the 3rd dimension that makes you think you're moving rather than just already being there). In that way, everything is predetermined (sort of) because it already exists and "free will" is an illusion created by your limited view of the larger field.
You, like Carroll (at least at the beginning of the video; I'm still watching), are making the mistake of assuming your local, 3 dimensional viewpoint and the math we can see from this POV is all that there is to see. It's like you're standing at the bottom of a well and telling everyone around you with great authority that the sky is only a small circle straight above you (when the reality is that that's only all you can see of the sky from your current position but it's not the totality of the sky). In this case, our "current position" is in the 3rd dimension (LxWxD) with a limited view of the 4th dimension (Time) and just a notion of what the 5th dimension might be (parallel timelines).
If even the top physicists say they don't know what Time is exactly and they are still arguing over whether time travel is possible, how many dimensions there are, etc. then why do you think YOU know "the right answer?" Nobody knows, but Aurélien Carnoy is talking about some of the possibilities that are actually being discussed by actual physicists, not just randos in a TH-cam comment section.
As far as "choosing your focus" and such? Who knows? Nobody yet. You could call that part "woohoo," I suppose, but the truth is nobody knows. Reality could end up being something that sounds hippie-dippy or it could end up sounding really mundane. Nobody has that answer yet. BUT if all possibilities already exist as reality as many physicists theorize, then any place you might "shift your focus" already contains you there. You're not actually moving anywhere, you are simply one variation of you/your personal timeline, so it sort of amounts to the same thing.
Personally, I draw the line at people anthropomorphizing the universe as trying to teach you something or having positive and negative paths... All that sounds like religion more than science, but, again, who knows? Anyone who claims they do doesn't.
"The singularity isn't a place, it is your future"
Stanley Kubrick enters chat
51:28 worm hole illustration. Do a mirror image on the right and you get the space of the universe as a giant wormhole. ><
A big bang that is not an explosion but an implosion.
Then every singularity is actually the same one appearing at different space and time. But it is as accurate as saying, we observe the singularity from different angles, one of those being time (wich is a way to classify the multidimensional nature of the inflation of a point in space)
Carroll's lecture starts at 3:34, for those not interested in hearing the person doing the introduction drone on and on.
Riddle me this, time machine can only go back or forward in time it cant move in space right? Our galaxy , solar system and planet is constantly moving so going forward or backwards in time just leave you in space.
Yeah also if you opened a wormhole, you'd have to be careful where the other end appears, or you might deposit a huge cylinder of stellar nuclear matter in your lab as it slices through the sun like an apple corer :D That would have made a good episode of Sliders
Oh now youve got me questioning every star trek episode in the past present and future. Dam
Good observation!
Maybe Star Trek isn't real.
@@bytheseaaspirinshop801it is life Jim, but not as we know it...
Haven't really got time to watch this now, I'll take a look at it yesterday evening
🤯🤣👍
If Sean Carroll and Danny Elfman collaborated, I would be so happy.
Happy Accidents.
Good movie. Love time, travel, and worm holes. 😊❤
"[...] JJ Abrams or Steven Spielberg or whoever is going to make the next great science fiction film [...]"
Definitely not going to be JJ Abrams
This is all based on the assumption that time is linear when we don’t really have any basis to judge that other than the first photon coming in to existence and travelling from that point in space. So that is our measure of time - we can go back to that point or forward from that point by tracking that very first photon. But who said that first photon didn’t ripple out like a wave viewed from a perspective of a 2D plane to us with infinite variance in angles. Who is to say multiple first photons weren’t created? It is just a philosophical question that science will never be able to answer. The only question in fact, of all the measurable quantities of our own existence, that is the single question which is impossible to answer. Personally I believe the only idea that satisfies it is the multi-verse but it is all opinion.
Indeed. If time travel is restricted to LINEAR time travel, paradox is a major factor and may indeed limit your ability to travel or interact in the past. If indeed there is a "multiverse," then time travel might allow you to go back and do anything...it only impacts your ability to return to YOUR point of origin...leaving you trapped in the reality you created or any reality compatible with what you did in the past. Your reality might still exist, but if you went back to it, it would not reflect what you did in the past as that reality never had you interact in the past.
Its IMPOSSIBLE for there to NOT be a multiverse. Energy cannot be destroyed, it can only be moved from one place to the next. Or transferred. Lets say you travel back in time in a LINEAR timeline, and kill your mother or father. Therefore YOU aren't born, would you just disappear or cease to exist? Of course not. Matter or energy cannot just be willed out of existence like Thanos snap lmao. You would simply be living in an alternate timeline. I think its impossible to disprove the multiverse theory. Its crazy to think that there could be an infinite amount of timelines or realities or universes but then again the nature of time and the universe is already crazy.
You make your future. And your past.
I could listen to this guy all the time...
I remember tomorrow wanting to watch this today
i remember this was required watching in my first year of temporal mechanics class in 2035
Damn, I wanted to go back in time and prevent my parents from having me...guess I’ll have to find another alternative
'another alternative' is redundant. Jus sayin'. :)
Haven't watched the video yet but wouldn't you just create an alternate timeline where you weren't born
Did it work!
Another hypothetical block to time travel is that as we progress in linear time, we are in fact really progressing on a subatomic level into a direction of entropy.
Suppose for a moment that our subatomic structure had an oscillation of sorts ... and as the oscillation progresses or operates, there was a slight bias or tilt outside of the perfect center or balance ... that would in fact project each and every particle, atom, etc into that direction of entropy. bit by bit ... probably on the Planck level of quantized time and matter.
In such a paradigm, there is no possible way any of us or other matter could ever pass into the past or future at a rate below or above that rate of oscillation ... in order to move that way, we'd have to pass through or under the Planck limit of size and time, in other words, outside of the space-time dimension we currently exist in, which is created and governed by the oscillation I spoke of, so if you could escape this dimension, you would literally cease to exist instantaneously ... and that's a very good thing in my opinion.
I know some of you will point to CERN and how they are supposedly trying to open portals to different dimensions ... and that is possible, however we won't be able to go there, but we could send or receive information to and from there ... and if there are beings in the other dimension whose composition is not regulated by entropy like ours is, perhaps they could enter our dimension in some limited form or essence.
In this particular discussion, I would say the D-WAVE computer system is most concerning to me, we are reaching out to a dimension below the Planck limit ... and I fear we may get more than we bargained for.
An other consideration on time traveling is that time is a concept, a tool to navigate a universe of infinite possibly happening simultaneously.
An infinite universe where every state exist at the same present moment is quite overwhelming for human mind, and not practical.
So our minds eliminate what is not useful, what is not used.
That is the conditioning every child goes through in order to understand, to stand in the midst, of human. It is required to have a "normal" human experience.
Once we got that human conditioning we can decondition our self.
Slowly we realize that to hear a thought doesn't mean it is yours.
Just like it is not you talking when you hear the radio.
That realisation leads to telepathy.
Slowly you realize that just because you feel an emotion doesn't mean it is yours.
That realisation leads to empathy.
We are not denying to have thought and emotion, but instead realize we are picking up thought and emotion from who ever think it is there's.
That discovery leads you to find peace with one's own emptiness, or spasciouness.
And to be able to identify with that emptiness.
From that renewed perspective, all that arise is the manifestation of emptyness.
We recognize ourselves in every moment and everyone we meet.
It is generally a slow process and at the same time instantaneous.
Looking back it took a long time, yet looking at oneself now it is instantaneous.
Every past , future, or alternatively possibly is imagined by you now.
So you are the empty space dreaming, imagining, visiting your infinite potential.
And as Picasso said "imagination is real."
Let me know how it feels.
Thank you.
The worm hole is still a lot more likely than catching an international flight now in the corona pandemic.
I know one thing : It's like living in a parallel universe!
If Time Travel in the past would be real, we would already have been visited by travelers from the futur, don't you think so?
Tommy Vasec .....If you were listening, Dr. Carroll explains how unlikely that can be, and why.
I will confess something to you Shirley Mason, I was quoting Stephen Hawking: "If Time Travel in the past would be real, we would already have been visited by travelers from the futur."
Now, if you were referring to Time Paradoxes, like killing your own father before you were born... bla bla bla, I'm tire of writing this lengthy comment now... but thank you for your response. ;-)
Please add "A Glimpse Beyond The Aether" to your must read list. Yes there is time travel as well as paradox issues. It is about a world that has irrefutable knowledge of what happens when we die. Imagine the implications? One incredible woman is the impetus that can prevent an apocalyptic tragedy on Earth. Author: Susan Frances Pegasus publishersWould love to start a discussion: What would it mean if we knew what happens when we die. Would it be good, or a disaster!
Tommy Vasec if they visit us they wouldn’t tell us.
IF we were visited by Time Travelers, the Travelers would have contacted someone of importance, someone who would have an effect on their past or our future, than would mean NONE of US, we (you, me and the guy down the street) are not important to the past, present or future of the planet. So no one would know, ever.
Future not futur
Humans are interested in time travel as naturally most of us tend to regret our past. Things we did or didn't do. If we had one more chance to do it all again we would do better.
And if we will have that chance we also will make same mistakes again.
@@friendship779 I wouldn't
Very smart and full of logics, nice lecture
You know, if you travel backward in time, you would also need to travel through *space* because the world is constantly moving through space, right? If you just hopped back in time, you would appear in empty space, the earth and our universe having not spun and expanded to your original location yet...
this reminds me of a story in a book i read as a kid, where someone discovered a time machine someone they knew had built, and the person who built it had used it and never come back. the person who found it imagined why, thinking that maybe they'd discovered wealth or something amazing, and eventually their curiosity gets the better of them and they use it, only to find themselves floating in the vacuum of space.
I suppose it should be called "travelling through space-time"
Too damn many ads.
download adblocker, Haven't gotten one ad on youtube in over two years....
Thinks comment was brought to you by Brawndo. It's what plants crave. It has electrolytes .
@@RexNunc brought to you by Carls Jr.
The ads are TOO DAM HIGH!!!
Great video. I watched it next summer.
Jan 27/19 time travel awesome lecture and comments
WHAT THE HECK IS UP WITH ALL THE ADS? I never ever complained about ads until now. Congratulations, you get a thumbs down.
funmeister
Since I'm using advertisement blocker add-ons on my browser, I haven't seen any ads. Not on yewtube, nor elsewhere. It takes five minutes or less to search for them an installing one or two. I'm using two, 'cause there are some sites detecting if an ad-blocker is being used, and refusing to show the content of the page. The additional ad-blocker that I'm using is not detectable by those sites and it does its job.
jewtube
So, you think TH-cam creators don't deserve to e paid for the time they spend bringing you videos? Do you work for free?
Not 1 ad for me thank god
You're welcome.
There is no past or future, everything is in the present.
Yes but as far a the dimensional shape goes... what we see as past is very much another “present” and we can go there... same with the “future”... they exist parallel with us, that’s why it’s possible to do.
@@addamriley5452 doubt it...
SmutnaJules007 rychwalska why?? You know quantum physics has proved this and are pushing to make it “fact” right. Wait, do you know we’re all literally the same person?
Addam Riley please expand on this or share where I may be able to find info on this??? I’m very interested in subjects like this. Thanks.
Ozzy no problem mate, but what in particular do you want to know?
Brilliant lecture!
whi is watching this 2035 ? in my hometown its a big popular show we love this. hope you enjoy it in the next years
Sean Carrol, I hope you read this. This is my thought. Tell me how it is wrong. Time travel backwards in time is impossible for anyone made of matter (that's all of us). Why? The matter we are made of wasn't created specially for us, but rather it has been recycled over the eons. The atoms in each of us were once a part of something else, something that we ate. Those very same atoms were the matter that made up countless other plants and animals over millions of generations, and at some distant point before the earth formed those exact same atoms were being cooked up in some unknown dying star. My point is that if you, a being made up of a certain set of atoms, go back in time to a point when the very atoms you are currently made of were scattered across the earth, or across the universe, then who gets your atoms? Unless time travel creates new matter, then you have gone back to a time not before your existence, but to a time when the matter that is you existed in many different forms.
Think of it simply: I ate a steak last night. I gained a certain amount of weight from that steak and my body used the nutrients from that steak. If I go back a week or a month, to a time when that steak was still a part of a living cow, does said cow lose a pound or two of flesh by virtue of my presence? Or do I lose the weight that I gained from the cow? You can't just say that new matter is created in order to make me. How would that happen? And how would it know to look like me? So basically there is a very fundamental problem with travelling backwards in time. I haven't seen anyone else even mention this. Forget the killing your parents and changing history stuff. You can't go back to a time when you, the actual matter that is your body, literally existed in many different forms scattered around the world.
Also, I don't believe that time is even a real thing, therefore there's nothing to travel through, but if it was real, that's the reason it can't be travelled through.
A physicist would say more or less the same thing by observing that not all particles obey CPT symmetry, so if you reversed the flow of time, they would keep goig exactly as they were, rather than "rewinding"
You've hit on the main problem with time travel. Time doesnt actually exist, it is just a reconsiliation of how we percieve our reality. To go to a specific time you would need to go to a configuration of reality that doesn't exist anymore. To "turn back time" would be to undo all the processes of the universe in the exact opposite way in which they took place previously which undoes our expirience of the events, unless our consciousness trancendends reality which I wouldn't rule out, but even in this scenario you could only go back to the moment when you set the event in motion as the process affecting the flow of events no longer exists after a certain point. unless you created a catalyst independent of the regular functions of the universe... and then how do you stop it?
Time travel is impossible because time is not an inherent property of the universe.
Even the idea that we are 'travelling in time' or 'travelling into the future' is just that . . . an idea.
'The Past' and 'The Future' are mental projections. They are not 'literal places we can go' or 'are going'
Positrons go backwards in time. No cows are hurt. In fact some now think the universe expanded in two direction of time. Matter went forward with us and antimatter when its own version of forward, the other way.
Time is an illusion just as movies are illusion of movement. It's simply our perspective moving through still frames at a rapid pace. For movies, its our perspective shifting quickly from one frame to another. For our 3D existence, its our perspective from one still 3D moment to another while being the body. Time is actually the spatial 4D just as time for a movie is a spatial 3D roll of film.
Time travel is indeed impossible as a physical body because of the reason you presented. However, there may be another way to time travel and that is proving consciousness is a form of energy. With it, we can theoretically shift consciousness to higher frequency and gain access to higher dimensions and would allow us to observe past and future moments.
Ziggy says there is a 99.99% chance that I'm not going to make it to the end of this TH-cam video.....zzzzzz
Had to read that twice to make sure I wasn't imagining the reference. Good one.
People downvoting: ‘hi guys, i know not of what he speaks, so imma downvote cuz i dont like big words’
Seems legit
The "time loop" part makes me feel really uncomfortable. If that means you'd meet your old self, does that mean you'd also meet your old self 2 loops back? And 3 loops back, etc? Wouldn't that mean you'd end up with an infinite quantity of matter in a finite space?
It means there is no time travel. :-)
So all his degrees are in imaginary things that's awesome
science has a billion legitimate pursuits and a lot of champions, none of them have ever come close to proving that time exists, much less a way to travel thru it.
Stopped listening after the second ad.
I didn't see any ads. Thanks Ublock!
Premjit Talwar .......Too bad.
Premjit Talwar Is it because you have the attention span of a flea? You missed out on a good lecture because you're a whiney little bitch ... too bad.
No ads here.
@@themidianite1645 then why do you keep watching ads? Just get rid of ads once and for all. Adblock or alike, take one minute to install and then you save hours each day :)
Love that Calvin and Hobbes is part of the pop culture montage
watching old films is kind of like traveling back in time as you can watch an event as it happened before you were even born
We can only see images of the past. You cannot travel to a molecular construct that does not exist any longer.
Time traveling is just remembering somthing from the past. Traveling to the future is using your imagination. Its up to u to bring it to the present. Its like flying cars. We already have flying cars(airplanes) but we refuse to call it a flying car because it does not look like a Ford fusion flying. Maybe for a car to fly it must take the shape of a B757. Maybe we already have time traveling (thoughts) but we refuse to call it that because it doesn't look like what we see in the movies.
Sorry, no time for this.
Ha ha ha
I'm pretty sure Prof. Sean Carroll is an extremely smart person. He's blowing my mind with this talk. Does that mean I'm stupid?
I can look back in time. I call it "remembering".
Remembering is not traveling. And remembering is flawed
elck3 Remembering is real. Time travel is a fantasy
Selcuk other way around pal... you just don’t know it yet 😏
That breathing prevents me from watching this.
Now you made me notice it!
The first issue should be . . . does Time exist as an inherent property of the universe as it is currently believed to be?
Or is it . . . entirely made up :) A human created concept and nothing more?
If it is just conceptual only, then time travel is a fiction.
And that would include the idea that we are 'travelling through time right now'
I was thinking about this recently! Considering we conceptualised time. The universe doesnt have a set time we only think it does because we created a tool of measurement for the forward motion of existential life. To measure beginnings and ends. I think time is one of our forms of essential measurements to attempt to understand the universe.
or better said time and space are not fundamental;they are emerging from the quantum realm
Berno Inferno
I guess you could look at time as a measure of cause and effect or just another way of measuring speed. The ticking of a second hand of a clock say moves from one digit to the next at a certain speed but seeing if we had a larger clock face the second hand would have to travel a longer distance between one digit and the next so it would make sense that the greater distance travelled would result in a higher speed needed to reach the same result so all we are doing really is synchronising this varying speed into a standanised measure that we call time so now a second is the same for a clock with a small clock face as with one with a clockface 10m across . Seeing as this is confusing to imagine then it’s easier to imagine time as a measure of cause and effect. The thing though we got to account for is that time passing feels ‘real’ to us even if we are in an empty room and we aren’t doing anything, it’s easy to think that cos one isn’t doing anything that there are no cause and effects happening . By what I have just described then with no cause and effects to measure within the room then shouldn’t time then stop from yr own perspective. Well no cause within yr body cause and effects are taking place so this is where our sense of time being a real thing comes from all these cause and effects happening within us give rise to our own body clocks so even though time is simply a measurement it does feel real.
But now that you have understood that then I’m gona throw a spanner in the works cos now take a photon of light, it doesn’t experience time. From its perspective as soon as it starts its journey it’s already at its destination even though we could measure that same photon travelling across the universe at light speed and we could say for instance that the photon took 4yrs to reach its destination , from its own perspective no time has passed. So to some up, time certainly feels real yet it’s still just a measurement of the speed of cause and effect .
It’s just one of those questions that doesn’t have a single answer, like for instance is space real ? You could go halfway to the moon step out of yr spaceship and say yep there is definatly space out here. But then ask yrself what actually is space, it’s a measurement of nothing, it becomes a measurement between Earth and the moon. If we forget vacuum energy and virtual particles then space is simply an area where nothing happens. You have one end where the earth is happening and the other end where the moon is happening and in between nothing BUT it becomes physical because although space is an area of nothing it doesn’t mean nothing can happen , an asteroid can wiz through it .
Soz I’ve gone on a bit but I was trying to raise the issue of whatever time (or space) is or is not, it is the way we think of them that makes them real, the more we try to measure or describe them the harder it is to answer the question as to wether both things are indeed real things.
I bet I’ve really got yr head buzzing now 😂, at the moment I’m trying to workout what actually is reality, so far I’ve concluded that reality too is relative and it seems that we are all in our own reality but realities can interact with others , is it this that makes our reality real ? . I haven’t got a clue but that won’t stop me looking further into it , it may be something that you would want to look into , but I will warn you I’m sure I’m going to turn “madd as a hatter”, before I ever get close to an answer . But if I ever did get that answer then things like time and space would also be answered as they would fall into the reality of being real. Yep I’m definitely gonna loose my marbles over this one, I hope you have more success than me cos I actually do feel that my reality is gonna end up being a padded cell . Lol 😂
Take Care . R .
Well as relativity says time and space are the same thing. Time as we use it is not fundamental but entropy is and time seems like a really useful tool to measure it.
Berno Inferno yes timw is real. spacetime is real. entropy shows that time is real
Wonderfully explained!
Since we all know that space expands, time travel would not only involve when, but where as well.
Today is Sunday, November 10, 2019 at 10:53 PM, so say I wanted to go back to Wednesday, April 10, 2019 at 10:53 PM, I would have to travel back not only in time, but in a *physical location as well & that is where the problem happens.
Location A (Sunday, November 10, 2019 at 10:53 PM) is not the same location as Location B (Wednesday, April 10, 2019 at 10:53 PM), as for starters, the earth never really returns to the same place twice at it revolves about the Sun.
The actual orbit of Earth is elliptical in manner, plus this orbit varies in a spirographic-like fashion in a space-time environment that is expanding, so, even if you could accurately return exactly to where you took off at, the space-time location would not be exactly the same.
Hence, there can be no paradox.
Is it possible to go back in time?
No.
Omg...it sounds like he has an EXCESSIVE amount of saliva...drove me absolutely crazy. Turned it off after 2 minutes.
Maybe your ears are too dry?
@@rodneywk1 😶?????
Yes! I made it to 10:45. Just cannot take it. Public speakers have got to train themselves. It’s a bad habit that can be broken if you want.
Too much compression on the microphone... Makes his voice quiet whilst increasing volume of breaths and mouth sounds. Eurgh very annoying.
seamus24 Thanks for the explanation. That makes sense. But, yes, still awful.
He mentions a book recommendation but doesn't give it; anyone know to which book he was referring?
I need help with my new years resolution. I've figured out how to change the stars.
My idea for changing the stars includes Orion and Pleiades (Subaru). I figure it's time to put something up there that's relevant to us, don't you think? Take Orion's belt and Betelgeuse becomes the head with a baseball hat. Below the belt are two legs bending at the knee. The feet aligning perfectly under the bent knees. The 3 stars of Orion's belt align perfectly as the 3 fat belt loops on a baseball uniform. The spear pointing at "Subaru" is the bat being swung and "Pleiades" is the baseball flying away after being hit. Put it all together and you get, "THE ALL-STAR." In my case, I see a left-handed batter and I imagine a "7" on the jersey. Which makes him, "Mickey." (As it should be ;-) But you can put any number you want, making, "THE ALL-STAR," any player you want. It'd be wrong of me to not, at least, try. This is me, trying. Pass it on, please and thank you. Don't worry, where I come from, crazy is a compliment. ;-P
Not correct what he says about physics. Cos my pop is a physicist.
You cant predict all that happens. Quantum leap. Harry potter indeed. Harry potter is totally gay.
Gay? NO - just a clueless incel maybe?
*Pulls wand from pocket and grasping it tightly in hand he begins to stroke his wand; gently performing a spell*
Anyone else never seen this guy but feel like they've known him their whole life?
I thought he was a comedian
He has a particular speech pattern that after only hearing him speak on Joe Rogan's podcast just happened to be in the last week it was recognizable without looking at my screen. Great speaker interesting person.
What if Choice is a dimension, like space and time? By "Choice", I mean the infinite branching of the multiverse, where events occur differently in each branch. Think entropy. Does a point in space 1,000 light years away from you exist, even though you can't get to it? Does a point in time 100 years in the past exist, even though you can't experience it? Does a decision where you had pancakes this morning, instead of having no breakfast at all, exist, even though you didn't make that decision?
Similar to how two objects can't occupy the same space slot, and two objects can't truly occur simultaneously (you can always add zero's to the decimal of time between them), two decisions could not occupy the same choice slot. You cannot choose not to have breakfast while also choosing to have pancakes for breakfast.
So, if you were to travel back in time to this morning in order to choose to have pancakes for breakfast instead of not having breakfast at all, that would create no paradoxes, because there does exist a universe where that choice happened -- you would just be occupying that universe instead. You would I guess technically be "time travelling", but really you would just be experiencing Choice differently, instead of manipulating time itself.
During the small Q&A session, you mentioned that if someone travels at the speed of light his watch will work normally with respect to that person. Now let's say there are 2 high precision atomic watches with built-in perpetual calendar. One is given to person A on earth and the other to a person B going for time travel. Both the watches are synchronised at the start of the travel. When person B returns to earth after time travel he will be younger than person A. But their watch should show same time and date. How can this be explained? I have been looking for a reasonable answer to this paradox for a long time.
I’m loving these presentations by Sean Carroll but on the lectern is that a Perrier or a Heineken? Lol. (I know it’s not a Heineken).
Lol. It had BETTER be a Heineken
I still am fairly unsure there are these assumed inevitable paradoxes when travelling through time (backwards). In a physical sense there is no reason why no two copies of really anything could not coexist. I'm also not sure doing a loop through time backwards to a point in the past means you have a direct impact on the future. What I mean with that is that the only person experiencing the world where there was travelled through time, is really only the *single person* that did so using a time machine or whatever other means. This means the literal only paradox that exists would be *killing your past self* , which still doesn't mean you would be killing your 'time travelling current self' that would still live on!! The question at the end also seems to suggest that the time travelling loop would never even allow you to visit yourself *before* starting the time travel itself. So essentially you would never visit the past in that sense.
Movie Primer depicts the concept of time travel just as professor said it would be possible.
Nice and fluently provocative
Sean starts at 3:30
I have no free will. Sean made me say this.
and I must give you a thumbs up, as I have done for the past 10 to the 23,945 cycles of this universe.