A take on time travel paradoxes | Paul Bunnell | TEDxEmbryRiddlePrescott
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- čas přidán 12. 11. 2017
- You're probably familiar with time travel paradoxes from science fiction, but what if there was a way to resolve them with real science? Paul Bunnell teaches Physics and Engineering students how to be problem solvers.
Paul is a Physics teacher at Prescott High School and teaches Engineering 101 at Embry-Riddle Aeronautical University. He began college studying mechanical engineering at Case Western Reserve University but discovered his passion was in teaching. He graduated from the University of Virginia with a Bachelor’s degree in Physics and a Master’s degree in Teaching. He believes most questions can and should be answered with data, but that sometimes we need stories to make sense of the data. This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at www.ted.com/tedx
had him for physics in high school, love this guy
Really? This guy is giving a talk about time travel in science fiction and he got the premise of Quantum Leap completely wrong! He wasn't travelling to alternate dimensions, it was the same timeline but he was in different people's bodies. Damn dude.
The paradox is the sound lol
There was sound ?
I concur! 🤣🤣🤣 Ridiculous!
Awesome presentation........... the implications of "science fiction" as interpreted by a real scientist. One smart guy.
I was here for this one. I loved the series we saw this night.
This video is AMAZING!! it has completely CHANGED MY LIFE!! I now know EXACTLY what will happen in the current futures past... It's all so clear... It's all right here, it's all right now... 🤯
This video is traveling at the speed of light and the sound can’t keep up.
Reminds me of Primer.
Also, a form of this happened in Back to the Future. 2015 Biff goes back to the ‘50s with the sports almanac, and nothing has changed in 2015, but when Marty goes back to 1985, everything has changed.
That’s stuff really doesn’t make sense to me at all. If something changes in the best, the effect is immediately going to be felt. Except you can’t change anything in your own universe, because what happened happened.
This video includes the absolute best explanation for the twin paradox I’ve ever seen.
It was so easy to understand because.... the explanation was all wrong!
@@ksbalaji1287 If you say so...
It should be noted that for individual photons time stands still or doesn't exist in our understanding. Of course a photon has no mass and can behave differently than a physical object.
This is an invitation to see and hear a theory on 'time' with an emergent uncertain future that gives us a new understanding of quantum mechanics.
Ok, this is an insane take on time travel, and I love it, But I do have a question.
It is possible to have two events in spacetime which cannot affect the other (their interval is time-like) but their future light cones intersect. Would this allow a change to potentially still affect the present in some way?
An example would be if I went back 5 minutes and told myself to stay on earth for a sufficient period of time, then I returned to my time and took a quick spaceflight that meant 5 less minuets had passed for me than if I had stayed on earth (which past me did). Would I return to find that the 5 minutes ago me has caught up, or does GR prevent this in someway?
Here is a paradox to think about. I hope I can explain it well enough. I recently made a hypothetical clock with a radius of 2862807095.5421653553357478091848m. The tip of the second hand travels at C 299792458m/s, thus the tip of the second hand experiences no time as time has stopped due to time dilation. Now we will introduce the twins like experience...
The tip of the second hand traveling at the speed of light is a spaceship that has a big tank of fuel to burn to keep it moving around the circumference at the speed of light. I am watching the ship from a position above and I can see it burning up its fuel tank as it goes around at the speed of light (The fuel tank is clear so it is visible to the outside observer).
But, for the pilot of the space ship, time has stopped, and as such cant be burning any fuel, therefor the fuel tank never gets empty.
For the outside observer the space ship eventually runs out of fuel and has an empty tank, for the pilot of the ships the tank is eternally full.
>
We can't have both occurring at the same time. The tank gradually getting empty and the tank always being full. :)
I wish I could go back in time after watching this video :P
Sorry, PP, but I kindof second that. Hard for me to follow some of this video. I tried but my mind is fried now ...
His stance on the time travel just seemed like a very convoluted version of the multiverse. He’s making it more complex than needed.
The blob of light from the laser pointer does not move across the surface of the moon, each photon hits a point on the moon and the next one a diferent spot, rhey are different photons not one photon moving across the surface.
Exactly. Good lord, this man teaches physics???
Very clever and original.
Good video for sleeplessness!
OBJECT PARADOX [meaning you go back and bring objects that today have been destroyed by fire or floods] Could you bring them back? Would the objects stay or would they disappear on their own.? 2/ suppose time travel is NOT the speed of light and faster....What else would it encompass....? 3/ Could we actually see time on a big screen, like THE TIME TUNNEL...and not travel physically yet...i think maybe it would be the start...4/ quest..if we did travel through time we would need a homing device strapped to us so we could return...
This is a totally preposterous notion. For example:
I place a time machine in a separate room with a lock. I only enter the room when I am about to activate the machine. I travel back in time to before I enter the room to activate the machine(lets say 5 minutes) and lock the door. I also have several other people who are WITNESS to me using the device.
What happens then?
The fact that I locked the room right before I entered it means from an outside observer there would be a huge paradox. One group of people witness me enter the room and turn on the time machine, but then they also saw me try to open up a locked door that had no way of being locked. Even with the speed of light horizon issue an outside observer would be in an position to see the overall sequence and also be affected and be effected by the changes to causality.
This is where alternate dimensions and timelines comes in as a logical solution to the problem. The best guess we have is if we were able to do this the universe would split into 2 discrete dimensions, one where I traveled back into time and vanished and one where I walked up to a locked door and there was another version of me standing on the other side.
Of course quantum mechanics is not that simple and we are beginning to comprehend that from a fundamental level time travel is not impossible, but that the amount of energy needed exceeds anything possible in normal spacetime. The speed of light is the speed of causality itself and to exceed it would require altering the fundamental nature of the universe to allow those conditions to happen.
Can you re-upload this please
All things are possible, mostly we don't really know as much as we think we do. Firstly we have no concept of a beginning.....which starts from nothing, so how can we possibly think of visiting a past event, or a future event. 1000 years ago Television, or most of our technology would not be conceivable, let alone thought about, but here we are.
shout out quantum leap. that show was dope
during my covid-19 quarantaine days i did a bunch of time traveling i time traveled to sunday april 29, 2108 because i was curious to find out if the world had ended or not and i appeared at this future hotel and could see alot of people in the hotel dining area eating the hotel dinner.
[Copy of my post on an old comment]
Here is a paradox to think about. I hope I can explain it well enough. I recently made a hypothetical clock with a radius of 2862807095.5421653553357478091848m. The tip of the second hand travels at C 299792458m/s, thus the tip of the second hand experiences no time as time has stopped due to time dilation. Now we will introduce the twins like experience...
The tip of the second hand traveling at the speed of light is a spaceship that has a big tank of fuel to burn to keep it moving around the circumference at the speed of light. I am watching the ship from a position above and I can see it burning up its fuel tank as it goes around at the speed of light (The fuel tank is clear so it is visible to the outside observer).
But, for the pilot of the space ship, time has stopped, and as such cant be burning any fuel, therefor the fuel tank never gets empty.
For the outside observer the space ship eventually runs out of fuel and has an empty tank, for the pilot of the ship the tank is eternally full.
>
We can't have both occurring at the same time. The tank gradually getting empty and the tank always being full. :)
This dude is my teacher.
same
I hope ya'll could hear him. It would be kinda hard to learn the way this audio is. Seriously, it's a fascinating subject
Sorry
Cant hear anything being said, and i really wanted to watch this one. Re-upload...or face my wrath TED!!!! 😈
Same problem used ear phones and it works
Try listening to the presentation using a Bluetooth speaker.
this guy could pass as michael stevens brother
Fix the audio please! Can't understand anything.
What's with the sound? It's really garbled to me
No sound! Hello? I can't hear you!
I came up with this idea decades ago, noted it as a story plot. If he wins a Nobel I'll demand my share! 🤣
Everyone has sound problems... perhaps future me is gaining revenge! 😂
Audio?
in a world of absolute abundance , the only thing of value,is extinction.
I myself have been in a time paradox before.
Pls widen the stereo a little more. I was able to get through 19 seconds before I got nauseous. We could easily get this under 10.
Theres no audio. How did it to 3k views
It works fine for me on the PC, but I get no sound when I cast it to google home mini.
Edit: I think the audio is out of sync. Google home mini is mono so when they add the left and the right channel together they cancel each other out. Try it with stereo or headphone, it might work.
We had to go back in time and cut the audio sorry .
I was just making up my own words and it's the funniest talk ever
It is low sound. I normally have it on 10% , I had to set it on 60% to hear this video’s sound.
I LOVE TO BACK IN TIME TOO AND ALL I CARE ABOUT IS THE PAST AND ONLY THE PAST AND NO MORE FUTURE FOREVER AND EVER ONLY THE PAST FOREVER AND EVER
Time dilation is relative to the observer. To the twin on earth, time has slowed for the traveler, but wouldn't time appear to slow for the twin on earth, as viewed by the traveler? Without knowing she was on a spaceship moving away from earth at near light speed, the traveler would think the earth was receding from her "stationary" position, at near light speed and it would appear that her twin was experiencing a slowdown of time. Wouldn't it appear her earth bound twin didn't age as fast as she did?
His twin is currently travelling at C with the better denims. When he arrives back on Earth one year later, they still won't be in style.
Prolly a thousand dollar pair of jeans while you joking.
Audio is not working on my cellphone
Uh i like his jeans
Your sound is Paradoxxxxxxxx
5:43 when light travels faster than light
in fact it's not.
Phase issues between left and right audio channels make it seem strange
Very Smart
Turn the bloody sound up. Can't hear a thing.
I love time travel theory.. but this guy could make fireworks boring..😴😴😴😴
I find he isnt great at explaining things
Time travel is only a ONE WAY STREET :-)
Indeed
Wow this audio is so glitched..
Oh, it works now..
You have incorrectly framed the twin paradox. The paradox is not that the moving twin comes home younger.
The paradox is that as the moving twin is moving away from the earth from the perspective of both twins the other twin is aging slower.
The paradox is only resolved when the moving twin stops and starts to return home.
Audio is just fine, at least in my time-slot...
Audio doesn’t work
No sound
Audio is broken
Time travel in 50 years
Time Remnants are temporal duplicates of yourself when u travel back in time from a timeline that no longer exists. For example, if you traveled back in time a few seconds and stayed in the new timeline with your past self, then you become a time remnant.
Time travel is surely possible either to the past or the future.According to Albert Einstein's General Relativity, time itself one day might be manipulated either via speed or gravity.
But u cannot go backwards in time with speed
@@myles5158 you just ave to be sneaky about it.
Those jeans are a paradox
Audio is indecipherable
You go back in time to prevent a murder, you are successful and the murder did not occur . If the murder did not occur, why did you go back in time ?
Basically the Grandfather Paradox
Sounds is not fixed for me...
No audio !!
I stopped watching this at about 7 minutes. Doesn't he contradict relativity? Doesn't light travel the at the same speed for all reference frames, and observers?
No. It travels slower in certain mediums, including air and water.
Yes, speed of light in vacuo, or, the speed of causality, c, is the same in every inertial reference frame. Keep in mind that c isn't about light; it's about, and is a property of, spacetime.
[The only relation c has to light, is that light travels at c when unobstructed by matter, as would any massless field - e.g., gravitons, if they exist. And even in a refractive medium, individual photons are traveling at c, even while the wave front is traveling slower, at c/n, where n > 1 is the refractive index.]
And no, he never contradicted c as a universal speed limit for physical objects, and for transmission of information.
Fred
@@ffggddss Actually the light on the moon example contradicts it. The light doesn't arrive on the moon at the same speed at all locations on the moon at the same speed as waving it two inches.
@@starcrafter13terran You mean where a flashlight beam is waved across a distant surface, like the Moon? That light is all traveling at speed c, going from Earth to Moon.
The appearance, when it reaches the Moon, is that a spot of light is traveling at superluminal speed across the Moon's surface.
This is illusory, because there is no object actually exceeding c; each instance of a spot of light at a given place, is a different collection of photons.
It's entirely similar to setting up a row of dominoes, each facing, not its neighbor, but off to the side, then arranging to topple them sideways, in order, at nearly the same time. It will look like a disturbance traveling rapidly along the row of dominoes.
It can even be done in a way that makes the "disturbance" travel faster than c.
And it can even be done, with a stick held parallel to the row, to make them all fall simultaneously, as though the "disturbance" travels at infinite speed.
But nothing there, is traveling any faster than the speed of a falling domino.
Fred
No
Sound problems!
Planck
why does the sound hurt my brain?
Audio epic fail.
Fix the sound!!!!
WHAT ?
OKAY, the sound is fixed, so lets discuss the theory itself -
His idea of the sweeping beam of the lighthouse moving faster than light is deeply flawed. At 5:45: "the spot of light travelling across the surface of the moon, isn't that moving faster than... light? and of course it IS". But no. While the beam is composed of photons, the *end of the beam* is composed of an ever-changing PARADE of photons. i.e. The first photon hits the moon; then the 2nd photon hits the moon a little to the east of the first.... the 3rd photon further east still, the 4th even further east, laying down a path of photons at the speed NOT of light, but at the speed at which the laser pointer back on earth is twirled.
Had to go through two amps to hear this. BTW I get that all the time on youtube.
This is why physics in college is taught so wrong. The light going to the moon is travelling at the speed of light. This guy is assuming that, in an instant, the light is arriving at the moon along it's path at the same speed. No wonder people can't seem to develop FTL travel. People don't even know the difference between actual FTL travel and hypothetical FTL travel.
Twin paradox... the space ship leaves speeding away from earth however, the earth is going around the sun at 22K per hour and around the milkyway at even faster than that then there is the galaxy moving in the local cluster wouldnt the ship need to travel at earths speed +x?
AW Crowe... all the matters is its speed in relation to Earth. This has already been demonstrated with atomic clocks in space.
Audio mmmhmmmf rrmmhmm pfff.
No sound. Fix it.
Einstein said no, so no. Enuff said.
Really???
Audio is totally garbled.
the audio is out of phase
I don't think this works. Just like the sound on the video
I don't understand...people are commenting here but you can't hear a thing from what he's saying :))). Perhaps they travelled back in time to hear the real presentation :)))
Hey Ted! Try watching these videos after posting. You won't look unprofessional. I bet the subject matter is interesting, maybe some sign language would help as I can hardly hear this and what I can hear is garbled 😂
The audio is effed up brah. I need some science in my mind right now. I'm so disappointed.
beyond bad
Avengers: Am I a joke to you?
The audio is aweful!
Dude! i can barely hear the dude... 👎
How we "Try" next time, i kbow its more work than ur use to with ur constant failures, i but so is the constant judgement you subject yourself to for those failures...
Just saying
NO SOUND👎👎👎
So dull and boring I had Boss-Baby style, head-rolling "power-naps".
What a waste of data, electricity, AND MY TIME!
Go back in time and wear better clothes.
Time travel is not possible because "time" does not exist! Time is relative to the motion of physical objects and is basically just a book keeping game we play with ourselves. The only "time" is the present and can only be experienced by an observer. This is proof of our creation and indicative of our special value within the cosmos. Infinity is not to be understood but to be experienced!
No sound