Is Time Travel Theoretically Possible?

[@scienceunbound460]

✅ Download Star Trek Fleet Command on Android using the Amazon Appstore: smart.link/ggcv1j1ayycvg Thanks to Scopely and Amazon for sponsoring this Video!

[@silenttoxic707]

I like this sponsor

[@robot336]

IF THE EARTH STOOD STILL WOULD WE HAVE LESS TIME = DIE EARLIER ?

[@robot336]

OR IS IT THE OTHER WAY AROUND?

[@RHCole]

​@@robot336We would all die instantly as everything on the planet would ignite from the friction of moving 1000mph while the land stood still/drown when the oceans swept over the continents and destroyed them 🤷🏻‍♂️

[@bourbon_sherbet1251]

you missed a paradox solver... read "Feedback" By: Dennis E. Taylor

[@Jayjay-qe6um]

"If you travel to the past, that past becomes your future, and your former present becomes the past, which can't now be changed by your new future." -- Professor Hulk

[@drbuckley1]

Consider the (Angry) Grandfather Paradox: Grandad grabs the gun and kills the Time Traveler. Does that create an infinite time loop between the two? Can Grandpa prevent the travel before the Times Traveler attempts the trip? What the .... !

[@AnuBis-kf4bg]

So back to the future is a bunch of bullshit

[@Brandon-io6us]

@@AnuBis-kf4bgit’s all theory’s

[@TheMILVSCR]

​@Anu Bis Die Hard...wait that's not a time travel movie

[@spinozilla4555]

How do people know that though.Last time I checked no one has gone back in time to find out

[@Vergo_LoneWolf]

I came up with a device while I was drunk one night at 4 in the morning that used the cylinder concept with an extrema electro magnetic that combined fusion energy while powering a fusion plazma Feild to collapse "it" into a micro black hole which you could theoretically "transmit / send threw" a micro/nano satellite into the past that we could scan for and detect today using radioisotopes! Technically achieving time travel!

[@thejudgmentalcat]

Thanks for reminding us that "The Past Was the Worst" ❤

[@33moneyball]

Lol…it was far better in many ways than today. Take a look at suicide and depression rates. Life is a meaningless swamp of nonsense today.

[@keithjansen2409]

As a young physics student i was posed the question how to travel backward in time. For coming up with the correct answer I was rewarded with 1 extra day of lab access,cleaning up the previous classes mess. The answer I gave was "just drive in the other direction of the guy going forward in time" . K.Jansen PhD physics

[@simonbeer8528]

We do attempt to look back in time via the Hubble/Webb telescope. The difference is we can only view, not manipulate.

[@ilajoie3]

Simon you need to share your time manipulation knowledge, you seem to work at least 38 hours a day with all your channels

[@thejudgmentalcat]

Clones, all with magnificent beards

[@OliverFoulkesMRO2013]

I'll take clones as a viable alternative to time travel 😅

[@jamesjellis]

He only reads the script. Other people write and edit the videos.

[@MinMaxxx]

@@jamesjellisso clones to read it all and basement slaves to produce scripts and edit.

[@zsoltbocsi7546]

@@jamesjellis good excuse but we all know he is using his big brain to time travel

[@ignitionfrn2223]

1:40 - Chapter 1 - Let's do the time warp again 2:35 - Mid roll ads 4:00 - Back to the video 6:25 - Chapter 2 - Gotta get back in time 11:40 - Chapter 3 - A most ingenious paradox 14:40 - Wrap up

[@duncancurtis5971]

Erased...from existence.

[@joxterthemighty]

"Let's do the time warp again" is the coolest thing you have ever said Simon!

[@134StormShadow]

It's just a jump to the left.......

[@RHCole]

My favorite time travel story is the novel 'There Will Be Time' by Poul Anderson. He uses the "You can't change the past" hypothesis and weaves a compelling tale from it. Good read, highly recommended 👍🏻

[@MrChristianDT]

I saw a comedy skit where the guy said that if he went back in time to change the past, he'd be the worst time traveller ever. "We have screens that can fit in your pocket & you can access virtually all information," "OH, yeah? How's that work?" "Shit, uh... I actually don't know. I should have figured you'd want proof, or-" "Who's going to win the World Series? Who's the next president?" "...Fuck..."

[@douggaudiosi14]

​@@MrChristianDT yOuR sO fuNnY

[@AndrewPrinster]

Give The Depths of Time by Roger MacBride Allen a shot. It's a three book series with using singularities to drop back in time.

[@airborneranger-ret]

Great book.

[@mandiemoore3272]

That's why I've seen or heard don't laugh is from Star Trek the newest ones not the card but the one with the girl named Michael and it seems I don't know I'm trying to find holes in it because there are holes there has to be but I haven't found them

[@danicalifornia505]

13:51 this is why I love the movie Primer. It was a final option of backwards time travel

[@deansheets]

One of my favorite simon channels out of his hundreds 😂

[@duartevilelas9688]

The wormhole and black hole options seem the most feasible. Black holes exist. It would be a matter of creating mini-black holes in a controlled environment (like small particle acceleratores).

[@M3PH11]

You just described the warp drive romulans use in start trek. They are powered my artificial, mirco singularities.

[@OliverFoulkesMRO2013]

So then use that to whip around the sun to increase speed exponentially and go save the whales! 😂😂😂

[@The1stDukeDroklar]

If we can manipulate the higgs field to remove mass from everything within the bubble, then that gets around the increasing mass requiring ever increasing energy problem.

[@oskarskalski2982]

​@@The1stDukeDroklarthe problem is that the higgs field is responsible for only 1% of mass. For example in protons and neutrons mass coming from higgs is 9 MeV (sum of mass of all valence quarks), whereas nucleons weigh around 900 MeV. The rest comes from energy of interactions between quarks and gluons that are whizzing inside proton at the speed of light (of course this is simplified picture). Yet if we have "disabled" the higgs while matter would have became unstable.

[@The1stDukeDroklar]

@@oskarskalski2982 From my understanding, anything that has mass acquires that mass from the Higgs field, including the particles. I do agree that the biggest risk would be that all matter within a field like that would not be able to exist.

[@mandiemoore3272]

I've actually watched interviews with Stephen Hawking where he says backwards time travel is the only thing that could ever be possible but our bodies couldn't withstand the actual force of the travel they would be as he said it's spaghettified only our Consciousness could travel back and it wouldn't be able to travel forward again so it would be stuck

[@AnantMall]

Whatt, link pls

[@manoloorz]

as it is implied at the end of the video maybe the impossibility of backwards time travel is the universe trying to tell us that the past was the worst.

[@Barnardrab]

We could put 2 black holes close to each other to implement time dilation. Isaac Arthur has a video called fleet of stars. Essentially, we would build massive fleets that could use gravitational tractoring to carry black holes around.

[@GoatAndDog]

The first thing I would do with time travel is I would be go back in time and give my youngest self good punch to the face.

[@themurmeli88]

Solution: punch yourself now, and feel good about in 2 years.

[@asylumental]

Its just a jump to the left.... And a little step to the right! Place your hands on your hips, And bring your knees in tight! But its the pelvic thrust, that really drives us insane... Lets do the time warp again!

[@rynoopperman5010]

I recently realised/ discovered that our solar system is moving quite fast so, when you go back in time, the other huge problem would be that our Solar system would be nowhere to be seen 😜

[@Nostripe361]

Personally I am a fan of the first theory for paradoxes. Whatever you did in the past has already happened so you can't change it all. The idea that you already did whatever happened in the past in your present just makes logical sense.

[@MarcioHuser]

ACTUALY, on satelites time runs FASTER than here on the ground, because the time dilation due to the Earth's gravity wheel is greater than the dilation perceived by the satelites in motion. Well, at least for GPS satellites. The satellites may lag 7µs, but dow here we lag by 45µs due to gravity

[@sogerc1]

I was gonna say.

[@MarcioHuser]

That would reduce the 1s skew to happen a little over than 72 years (the sattelites' clocks being 1s ahead than Earth's)

[@chrism3784]

@@MarcioHuser how about geosync satelites that are even further from earth and are only moving earths rotational speed, approx 1000 mph. even worse time dilation

[@chrisboyer4348]

Shit got real when he started discussing going back in time.

[@QBCPerdition]

I've always been a fan of the first option, if you go back in time, whatever you do is already what happened, you can't change the past. And while this would seem to remove free will...I already believe that is an illusion, so no biggie.

[@sschmidtevalue]

Not mentioned is the fact that we are constantly moving through space at a high speed, both around the sun and around the galactic core. To travel through time to a past event, you'd also have to travel through all the space we've traversed between events.

[@rreece90]

The Earth will also be in a different place in the future, and yet there is no problem with time travel to the future.

[@sschmidtevalue]

@@rreece90 Time travel to the future usually involves time dilation, which is a natural feature of motion. To go backwards in time would require some other mechanism. And if that mechanism doesn't have a spatial navigation component, you'll wind up in the wrong place at the right time.

[@rreece90]

@@sschmidtevalue It's almost certain that, if possible (BIG if), time travel to the past wouldn't use a stationary device like in movies, but a wormhole... And moving through space is the main "feature" of a wormhole (moving through time being kinda a hack - by using time dilation to move one mouth to the future and then entering it to leave through the second one at an earlier date), so I think there would be no problem. We would "just" had to keep both mouths close to Earth.

[@flessuh]

Thing with traveling back in time most people forget is that our entire universe also moves in space... So even if you could travel back in time you would also need to move to the position our universe and the orbiting planets in it was at that point in time...

[@jeffbergstrom]

This was actually a really good overview of the subject. Good job. Most KZbin channels would not do so well.

[@ThatWriterKevin]

Thanks!

[@drbuckley1]

Yeah, maybe a few tiny mistakes.

[@jamesroseii]

I'm calling it! I've figured out how to travel backwards in time! We fold ourselves into the 4th spacial dimension, then entangle that curled up dimension with a partical that has negative mass, then BOOM! Bob's your uncle!

[@robd9413]

There is another What. Fixed timeline, singular. You got back because you always went back. Your presence at any earlier time was always part of your standard timeline. You can't kill your relative because you didn't. Similar to the "time wouldn't let you" idea and avoiding any messy multiverse stuff. The most popular (almost) example of this was Avengers: Endgame (which was then completely undone in the Loki series, but that's a different story).

[@KarlFarbman]

An extremely concise - perhaps too concise - summary of several concepts I've been studying for over a decade

[@graciesugarbee]

Idk how it got past me but this is literally the only channel Simon has that I didn't know about lmao

[@vomder]

Something I would like to have seen mentioned in this video, which is tangently related would be looking through time. This was part of the plot of the Denzel Washingtion movie, Deja Vu.

[@ghost9955]

Love the outro. The past was indeed the worst!

[@drbuckley1]

First, acceleration does not increase an object's mass. Mass is mass is mass. Second, every observer's experience of "time" is equally valid. The astronaut would experience time naturally on her trip but observe that clocks on Earth are moving unnaturally fast. Third, consider the "Angry Grandfather Paradox"; Grandad grabs the gun and kills the Time Traveler. Would that not create an infinite loop in time?

[@Dank-gb6jn]

You should do a video on the plausibility of “The Day After Tomorrow” (2004); where NYC completely freezes over due to a catastrophic natural disaster.

[@M3PH11]

Go do some reading on something called the "ice age"

[@OliverFoulkesMRO2013]

That has been busted a long time ago (in YT years). The extreme temperature change is possible. The timeline isn't. Is that video still available...no clue, but it was a very interesting thought experiment

[@danieltempas6062]

Time travel into the future has always been possible, we do it every day. But travel into the past is impossible.

[@southcoastinventors6583]

Even that not really possible since the craft has still traveled the same time its just frame of reference has experienced less time or both frames are different.

[@ralphharrison6622]

highly unlikely, sure, but not impossible.

[@danieltempas6062]

@@southcoastinventors6583 When we sleep... we time travel.

[@MrAlfable]

*Make a comment demonstrating you haven't watch the video without saying you haven't watched the video.*

[@SportsFan838]

​@@danieltempas6062 Sleep isn't the only way we travel to the future. If we stay up until midnight then we are now in a new day

[@ZatoichiBattousai]

Ummmmmm Actually; More like Hypothetically, rather then Theoretically!

[@pdxdogg6891]

Good work. The first part of this movie try's to give you a sense of the smell of 1800s London. Perfume, The story of Murder.

[@jasonjuneau2948]

What about a reverse paradox? What if someone builds a time machine, travels to the future and sees that its a utopian society. Then travels back to the point at which they left and tells everyone and everyone says wow, that sounds amazing and everyone jumps to the future. Would that future still exist because there would be no one in the present which would be the past in order to build that future?

[@The_SCPFoundation]

If someone invented backwards time travel, that moment of energy use would almost certainly cause a localized singularity on that point. All matter in our observable universe would collapse into it which could explain the cause of the big bang. Also that solves the fermi paradox. When a civilization advances too far in knowledge, it doesn't advance fast enough in wisdom to protect itself from it's own abilities. There were scientists scared that splitting the atom successfully during the Manhattan project would trigger a chain reaction destroying everything. But Nazis were worth taking the chance anyway. That ability to end all life is terrifying in the hands of flawed humans. The further we advance, the higher the stakes become when we roll the dice of reality. We can already destroy our world if we choose, in 500 years we may be able to destroy our solar system or even our galaxy. So for our future's sake, let's not attempt to reverse time lol. The juice isn't worth the squeeze.

[@danoliver7044]

I think once we begin traveling across vast distances in space we will begin to see/experience time traveln but it won't be anything like we imagine when we think of TT at the moment. It will be more about perspective and differences in how we and others back on earth experience time during our long space journeys Like a crew go for a voyage across the galaxy using whatever technology, going through worm holes and experiencing time dilation from going near black holes and using stasis or some form of hibernation tech. When they return the people on earth would of aged much more than the crew

[@lionzod6943]

In the game series Mass Effect there is an element that allows mass of items to be altered and its used for space travel. Might be interesting exploring if that’s plausible at all. I dont think ive heard of elements that alter mass even theoretically

[@metroidhunter965]

Well, radioactive elements cause humans to lose mass relatively quickly.

[@themurmeli88]

ME's element zero is unfortunately just the equivalent of DA's lyrium, it's just (space)magic.

[@RHCole]

​@@themurmeli88It's just manipulating the higgs field, a theoretical possibility.

[@mashi81]

Kyle hill would be so pissed at the fact that you used the paper+pencil demonstration of a wormhole 🤣

[@Grizzdrop]

There is the 4th possibility which was seen in a book called “by the light of the moon” by Dean Koontz. You can go back but not really… you can observe things but change nothing as if you were a ghost

[@sogerc1]

That seems even more far fetched.

[@southcoastinventors6583]

@@sogerc1 Exactly that just fantasy.

[@olixpatdo8181]

I gotta read this

[@M3PH11]

The part where Simon said "all the theories rely on something that is either impossible or doesn't exist yet" was lost on this one.

[@SkunkApe407]

Dean Koontz is a FICTION writer. 🤦‍♂️

[@andeeharry]

This stuff is going to get very messy. 1. You need Math, Georgraphy, Science, Mapping/Coordinates and compass learning. Since the Earth spins and moves constantly, you need to plan your moves carefully, as otherwise you will be stranded in the wrong place. 2. You need to figure out how to survive being ripped apart and being put back together again while you rip a hole in the space/time contiumum. 3. Your stuff will become obsolute, nothing will work anymore. In the past or future. You will have a headache on your hands trying to figure this out. You have to be careful, because society will probably try to kill you for being dangerous. 4. Your not in your time frame anymore. 5. Travelling can be dangerous, since you could accidentally alter the timeline, but giving people stuff that they not ready for/technology, virus, or something.....future or past. It is dangerous. You never know the outcome of this time. 6. Time will catch up with you quickly....meaning you'll age too fast. 7. You have gone missing. In the future, or return to the present. You have been missing for some time and now you have to explain yourself....somehow. In the future, that would be a nightmare, since everyone you know is gone. 8. Make sure the fuel you use for your machine is worth it, as you will need it for whatever time period your in. 9. Time Travel is hell....because you can't talk to anyone, share knowledge with anyone. You have to play 'Prime Directive' and not interfere with anything, no matter how much you want to.

[@GoofyOldGuyPlays]

I like the Futurama interpretation of going back in time. Just go fast enough forward in time until the universe collapses upon itself and a new big bang happens and wait for the timeline to catch up. :D

[@Zer0TheHer0_VR]

2:37 explanation of what he meant by relative to the observer on earth…you are always experiencing some form of time dilation due to the motion of the planet + the motion of the solar system moving in rotation with the galaxy + the galaxies motion through the expansion of the universe…that’s not including what we experience due to gravity

[@idleEverything]

Backwards is possible. You record the exchange on molecules in a small space, then reverse it. Once we find a way to do so. Physics overthrown.

[@ralphharrison6622]

hmu when you get that worked out. exploitation time, lets go!

[@magic76767676]

10:36: 2 black homes. Roy Kerr! Now you're talking. The novel, The Galactic Time Trap used this idea.

[@boldandthebeautifulgimbal2881]

3:13 Simon, let’s do coke. Engage!!

[@anonymousrex5207]

As interesting as it would be to visit the past, I always found the idea of a temporal viewing machine (like the one in the movie Paycheck except can work forwards and backwards) to be a much more compelling idea. You could see things without messing with the past and use that information to solve the various mysteries of history, which I think would be fascinating.

[@anticorncob6]

Or you can travel there but you only exist as an observant "ghost" who can't interact with anything. So a more sophisticated version of what you described.

[@silverherogoldsmith2661]

I hope we can go back to the past someday on September 2022.

[@TheMILVSCR]

The great Nolan movie, Interstellar gave me (maybe us) the coolest example of "time is relative" that I've seen so far. Isn't there a clock example of time varying, to relativity, from space shuttle (miss watching that happen as an American) missions?! I can't remember it thoroughly, but I remember it slowing down. It matters where it's important. "Oh no, I've gone cross-eyed"- Austin Powers

[@kasieream1248]

I think you should do something on human hibernation

[@itstonberrytime]

If time travel into the past were possible, we would already know about it. Stephen Hawking threw a party for future time travelers, but waited til the day after to send out the invitations. Since no one showed up, that means human beings will never figure out time travel. Case closed.

[@seanmorgan2356]

Whoa. Cool graphics!!! Maybe whomever did them can make it look like Simon's neon light is working.

[@Istandby666]

I learned how to travel back in time. I booked a vacation to Sydney Australia. On the return flight. The day and hour I left was the same date and time of arrival...😁

[@Twi66e]

“Let’s do the time warp again” you just made me travel back in time to those camping holidays when I was a kid dancing to that song 😂

[@sirhammon]

Galaxy Quest got it right. Time = rate of change relative to other rate of change. Each particle in your body is experiences time at a different rate because it's moving at the different rate through space and has different amounts of gravitational time dilation. If the universe moved into the exact position it was 5 minutes ago, it's not 5 minutes ago. The universe can be exactly the same billions of times. You can simulate traveling forward in time with time dilation. The universe ages 10 years and you age 1 minute. Cryogentic freezing works too. Or Computer simulation. Computer simulation is the only way to experience the past, unless you alter every particle in the universe back to a previous state.

[@batteredskullsummit9854]

Edit: My statement may not be correct semantically speaking. What I mean is that at it's core, time is the measurement of different events happening in sequence. The quanta for time is a "Planck time unit," which is the smallest known useful measurement of time. It is the amount of time it takes for one photon to travel one Planck length. So time always boils down to measuring one thing happening after another thing, always with respect to the laws of thermodynamics, which precludes "traveling back in time." The universe only ever exists in the present. It isn't a VHS tape you can rewind and edit I think it's important to remember that time only exists as a tool to measure entropy, it's not a thing you can choose to go back and forth in. You can only change the relative "speed" of entropic action ("passage of time") for a given object by changing its mass, velocity, or the mass of other objects acting on it via gravity

[@DaniiQuaza]

I think it would be better if we could see the past through a screen until we want to go back to a cosmically safer place someday when entropy and supernovae become problematic.

[@windrider65]

I'll just wait for the time Lords to leave me a TARDIS.

[@magic76767676]

11:51: Grandfather paradox. time travel = Alternate realities is the obvious solution. Assuming time travel is possible and a solution can be engineered. 16:22: Why would you want to. Exactly! While cool, it doesn't seem to have practical use.

[@TheFinalChapters]

Common misconception about backwards time travel: you're traveling back in time, not the universe around you. That is, even if you were able to sustain it, it would be you that's getting younger. Life doesn't really work if you go in reverse, so this would basically be a death sentence. And on a related note, if you could figure out how to make, say, the earth go backwards in time, you'd very quickly destroy all life on it. So good job.

[@minu.6619]

I honestly thought Simon was going to end the video with 'the past was the worst' XD

[@jimmybisk]

Thanks for a great video. I find this topic fascinating. While I think it would be near impossible to achieve, I've thought about this for many years & I've come to the conclusion that, while highly unlikely & would still take more than we have right now, we could possibly see back in time as opposed to actually travel back. This is a collossal What IF - so don't take it as fact or anything but as far as my small brain goes, I understand that the light from stars reaches us many years after it left the star. I have also heard that if we built a collossal telescope in space, we could actually see planets. Imagine if we built one so big that we could get a Google Earth level zoom on a planet orbiting another Star. Just supposing that planet was occupied by an equally intelligent race. Now take a date, like the Battle of Hastings - 957 odd years ago. So if we look for an inhabited planet orbiting a star 957 light years away, we could see what was going on there 957 years ago. Now imagine if they did the same to check out Earth, then right now, they could be seeing the Battle of Hastings. OK, here's where the idea gets a bit more wacky. In order to be nice to them, we erect a giant screen in our solar system showing them their view from our perspective, allowing them to see their own past. IF they did the same for us, then, well, there you have it, we could see into our own past. Of course that would mean they would have to be 957 years ahead of us & we'd have to be far more advanced and have a ton more resources than we currently do to achieve it, but it's not impossible I'm sure some big brained scientist type will tell me that's wrong because of x, y and z but it is just an idea & I'm no physicist. After all, it's crazy dreamers that put this stuff on the map! Thanks for reading.

[@Julia-uh4li]

Interesting idea. If we did have a way to accomplish that tech now, we still might never find intelligent enough beings that could understand what we were doing or that could do what we'd accomplished. Like I said, it's interesting.

[@Alec0124]

This would only help us see as far back as the giant mirror was set up. So no ancient history, our descendants* could maybe see us? cool... OR we'd have to travel faster than light so that we could catch the light we reflected 957 years ago.

[@robot336]

IF THE EARTH STOOD STILL WOULD WE HAVE LESS TIME = DIE EARLIER ?

[@robot336]

OR IS IT THE OTHER WAY AROUND?

[@ralphharrison6622]

wow. bro, i have no clue wtf you just wrote, but i get the concept. seeing rather than traveling in time. the only worry id have is the realization that people would be able to witness the truth of religeon. that would cause massive civil unrest, to put it gently.

[@Mayor_Of_Eureka17]

If there was a theory that worked its in Donnie Darko.

[@light-master]

The problem with anything with any mass travelling faster than light, is that while travelling at a higher and higher percentage of the speed of light requires a larger and larger amount of energy, and travelling at the speed of light requires an infinite amount of energy, to go faster than the speed of light would require more than infinite energy, which doesn't make logical sense.

[@oskarskalski2982]

Actually that is not 100% true. Yes, things with mass require infinite amount of energy to accelerate to the speed of light. But in the recent paper about "superluminal observers" polish physicist Krzysztof Dragan hyphotesise that in Special Relativity there is a space for objects traveling faster than light. And here it would require infinite amount of energy to slow them down below the speed of light.

[@theawesomeman9821]

If I could travel back in time, I would go back a few years with a sports almanac and make a fortune😊

[@gugman9684]

Depending on how far back you go and as long as you had the period-appropriate money for it. Otherwise, it might appear like you are trying to pass off strange counterfeit bills. You would have to be like Doc Brown in Back To The Future with all his stacks of cash from different time periods to make it work.

[@chrism3784]

@@gugman9684 if you went back in time and won tons and tons of us currency, it would still be legit in the future. would look strange looking so new compared to being how old the bills were. you just can't take new printed money backwards

[@theawesomeman9821]

@@chrism3784 I was just referencing "Back To The Future".

[@IridiuLugia]

4:16 Claaarksoooon! You broke spacetime you muppet!

[@chrism3784]

Another thing to think about, if you go back in time, you will have added mass to the universe you went back to, so it would be the universe plus your mass. Gravity will ever ever so slightly be more in your part of the universe. Mass is basically very concentrated energy and you would have added it to the universe, energy cannot be created or destroyed. Only way it could work is if all the mass in the universe that would have later become you that traveled back would have to be destroyed. Meaning any and all the mass on earth in the time you went back to that was to later make you, the cloths you wore, the time machine you were in and any other mass you brought back would have to be destroyed in the world you went back to. So the water molecules that later you carried back would all disappear, the proteins, calcium in your bones, all of it, in the new universe you went back to. Some of that mass would be in the new ocean, some of it part of another living being, all would disappear when it is introduced back from the future.

[@JoshuaDracul]

10:20 “Black Holes Simon” 😂LOL

[@gabrielrodriguez821]

I was watching doc where they talked about the old idea that time goes in a loop so in theory you can travel to the past but that type of time travel goes so far in the past matter won't exist where you end up.

[@dwaynelangerhr6985]

Well Simon if you are talking about the Bad smells of cities and towns in the past depending on what city you live in today you would have to travel back in time to get away for the smell.

[@magic76767676]

11:08: Steven Hawking proposed a time machine using a worm hole. I have only seen it explored in the book, Wasn't Tomorrow Wonderful.

[@johnpaulgonzaga5997]

Thanks for finally making this vid Whistler/Fact boy!

[@1966human]

Yes it's a strange situation - can we time travel - yes it happens all the time, can we practically time travel - no or not yet, can we observe past or future events in real time or past or future sound or broadcasts - maybe now at military level or in the future

[@grendalnewgod]

There are more ships and crew members now in Fleet Command. TOS, TNG, Films, Discovery, Brave New Worlds and Below Decks. Playing ATM.

[@aceundead4750]

The only reason to travel backwards through time is to be eaten by a dinosaur.

[@FYAjibber000]

Didn't you see Terranova? It's for when we screw the Earth so bad our only hope is to go back in time millions of years and try again

[@Nathan-vt1jz]

PBS Spacetime has some excellent videos on this topic.

[@anthonyd3315]

Can we get him to do a video on Time slips. Timeslips meaning areas where the fabric of space and time don't function normally and if you pass through one you can end up in your exact location but at any point in time past or future.

[@XtreeM_FaiL]

In a theory it should be very simple to travel back in time. Just turn mass into negative mass and it will instantly moves faster than light and time dilatation kicks in hard. Just don't ask what happened to acceleration.

[@Jose_GRS]

Yeah so easy to create negative mass

[@XtreeM_FaiL]

@@Jose_GRS It might be easy, who knows? But first we need to find out is negative mass even possible.

[@Jose_GRS]

@@XtreeM_FaiL I feel like we won’t be able to time travel unless a supernatural occurrence happens like aliens come to earth and give us a warp drive or drop a traversable wormhole next to earth

[@heatvision21]

This channel should have a video on a "shrink ray" or something like that.

[@LemarFrench]

The universe is so vast, you can quantify "time" within a measure of "space"...so moments occur at the speed of light with respect to mass

[@wilfridwibblesworth2613]

Imagine going back in time to meet Jesus and it's Simon, not only a prophet but the first person ever to wear glasses.

[@stephanybrown3226]

My favorite show featuring time travel is Primevial, a BBC show featuring Anomalies or rips in time. Highly reccomend if you are into paleontology or sci-fi- just one warning, both the ofiginal and BBC/Canada spin off never finished.

[@thatguy66199]

Alcohol is a great time travel device. And much like in Terminator, if done correctly you awake with no clothes on and unsure of the date

[@TRPrecht]

Playing STFC while watching this video with an ad for STFC.

[@michaelmoore7975]

I have a time conveyance. I get in my truck and start driving. I look out the front window to the future. I look at my rear-view mirror into the past. And I look at the clock on the dash to the present.

[@MaryAnnNytowl]

I know I'd give a sacrificial limb to go back and fix something that I never saw coming. Wouldn't even quibble over the price.

[@johnlane7529]

I think that people forget that the Earth moves through sapce so even if you did go back the earth would not be there.

[@chrism3784]

yeah, and the galaxy is moving through the universe at super fast speeds towards the great attractor. depending on how far you'd end up in a space outside the galaxy, or the very least super far away from the sun, in the middle of nowhere in the galaxy

[@Nick-fh4wd]

We can assume if time travel was ever achieved, they either did not visit as far back as our current time period; or if they did then they did so undetected. Alternatively we could be timeline A the original timeline and that is why there is no evidence of time travellers yet. But history could potentially change in the blink of an eye if we ever master time travel.

[@Nick-fh4wd]

However it is also possible that time travel was discovered but the human race and our solar system has already been reset back to a time that pre dates it's discovery either intentually or by an unexpected space paradox

[@RossAlexanderSmith]

Things don't get heavier approaching the speed of light. Inertia increases towards infinity. If the mass increased, the incredibly fast moving particles from space would have huge masses that would interact with slower matter in very unfortunate (to living things) ways.

[@southcoastinventors6583]

It should be titled how can you possible travel faster than your exhaust.

[@MrBahamutt90]

Head cannon is backwards time travel exists in the future. But it is heavily illegal. The first person broke the timelines, so they went back and stopped him, this fixing the timelines. They then started sharing rumors and theories throughout time to scare people off of ever trying it.

[@kellyong107]

For going back to the past, meaning those frictional movies like star wars and star trek where they hyper jump travelling lightyears in just seconds meaning they reached the speed of light and thus, they should travelled back to the past

[@marystone860]

"Wibbley-Wobbly Timey-Wimey" LOL! 🤣 DW

[@edpoell2876]

Going back in time you are expecting the universe to go back to the same positions held back in that past time frame. Show a picture at night with the stars visible and the date of the photo can be determined by the heavenly body's positions. In order to achieve the exact moment in the past you are trying to visit the entire universe has to go back to the same positions it occupied at that very moment.

[@thomasciarlariello3228]

I had bet about Feynman with Dr. Scott Chubb during an MIT engineering conference I was invited to.

[@the_lotharingian]

Here is my out there time travel theory=. My maybe each individual soul is their own timeline in the multiverse and every probability is true but it collapses into the observers reality and maybe a collective matrix forms periodically

[@fortyfukinseven]

My biggest problem with reverse time travel is the conservation of matter/energy. It cannot be created or destroyed, only change form. The food you ate today to sustain your body was once plants and animals. Those were once other things. The things making you up used to be something else. If you go back 3 weeks, all of the nutrients sustaining you will suddenly me in different forms and in different places. Basically, you'll be ripped apart on a molecular level more and more the farther back you go. You can't do the many worlds thing because you would be introducing new matter into an existing universe, thus breaking the laws of physics.

[@Alec0124]

I like the final option, I agree it makes the most sense. I would expect to see someone immediately appear before me if I turned such a machine on. edit: ofc getting the spacetime coordinates right must be really hard. I mean we're always moving through space...

[@jamesjellis]

Consider this. It takes less than 60 seconds for the earth to travel a distance greater than its diameter. There is literally no room for error.

[@rreece90]

Time travel to the future is possible, and there is no problem with coordinates. You just have to keep close to Earth as you move at a fast speed.