We Traveled Back in Time. Now Physicists Are Angry.

[@kurzgesagt]

Go to brilliant.org/nutshell/ to dive deeper into these topics and more with a free 30-day trial + 20% off the premium subscription! This video was sponsored by Brilliant. Thanks a lot for the support!

[@suplitis]

hi

[@glefyr]

To Claim Their Bones ⚔ 50 (45+5) Atk Weight ⯀ Amt. x0 [Before Attack] For every 7 Poise on self, Atk Weight +1 (Max +2) [On Use] Until this Skill ends, this unit cannot be Staggered from taking damage [On Use] Deal +2% damage on Critical Hit for every 💨Poise Potency on self (Max 50%) +30% Damage on Critical Hit Deal +0.5% more damage for every 1% missing HP on self (Max 25%) If this Skill targets only a single enemy, deal +100% more damage (In Focused Encounters, a single Part) (IV) [On Hit] Inflict 3 🩸Bleed [On Hit] Inflict 5 ⚡Paralyze next turn

[@glefyr]

@AUTTP-i2n good bot

[@idkthetime]

AY YO ! @Geopoldd

[@andrewpark3325]

Dont like this comment

[@olafmesschendorp147]

"One beer for me please" he says A Tachyon walks into a bar

[@asghlv5841]

ha

[@khanes5376]

He gets out of the car. He drives for fifteen minutes. A Tachyon got into the car after a long day of work.

[@MrCheese270]

Hohoho!!! What a kneeslapper!!!

[@Toadfish10]

Why is this joke so good

[@SabertoothSeal]

Superluminal Tachyon! Super who? Super. Who's there? Knock knock.

[@nlswchrng]

What this video taught me is that speeding makes you live longer

[@normanwolfe7639]

Not really. Just from the perspective of others. Did I get that right? I have a headache.

[@remnant24]

Yet on average, speeding makes everyone's lives shorter.

[@vkobevk]

sorry, nope your life time stay the same, but it is just people outside your ship go older faster than you, but time for you stay the same than if you stay on earth, so one year stay one year for you the only nice thing it is instead to take 4 years to go to alpha centauri you can shorter that to few months if you move at 99% light speed

[@AIForHumansShow]

Then Ricky Bobby is the oldest human on earth.

[@prwtarxikos]

If you run faster you ll see more images, or info or feelings etc. But if you run slow you live the moment with continuum causality not virtual. People interacting with numbers or words need speed cause connectability or inspiration, even memory is connected through present time and through the work of multiple people. But it is another thing working for a living or sharing with others experiences and other thing to experience it from within. Eventually we ll find a way so that both will function at the same time..

[@Dang.-]

The message saying "Run" to the twins from before is gold 😭

[@clivah1499]

the lore

[@hamza-chaudhry]

Could be a great movie

[@HarpSeal]

A FELLOW SEAL

[@BooLightning]

I saw this comment before I saw that in the video

[@HateBadPeople]

@clivah1499 the GLORIOUS lore

[@THE_crxqy]

"We're twins!" "Really? You guys don't look the same age." "It's complicated."

[@famcamp3414]

"But perhaps not as complicated as you may think. 🦆" - Kurzgesagt probably

[@betterchapter]

Excellent video. Will have to watch it again yesterday, since I've already seen it tomorrow.

[@PerpendicularFlight5]

Source?

[@dawnstarrunsonpawz]

@@AUTTP-b8lit was you!!

[@ValidatingUsername]

Except it’s entirely wrong

[@bi-00i]

Quote: "But who would save you with the arrogant criminals from the chastisement of Allah the One, the, Subduer?! Where is the escape from the heat, evil and spark by the passage of the planet Saqar that's coming from the southern pole?!Despite that the sun is in the north pole, as well the southern pole is suffering from the heat of planet Saqar in the month of July and August although it is supposed to be in the harsh winter season because of the suns’ departure away from it, into the north east of summer, and the question that comes up to the mind and logic: What is the cause of the currant winter’s heat in the south pole? In fact, the level of its effect on the thermal summer of the sun. Since when does the summer of the sun get thermal heat due to the heat of winter?! In fact, the cause of the current winter heat in the southern pole is simply due to the heat of planet Saqar which I warned you from its passage from the south side of planet earth, since over than twenty years ago, and the current month of Safar, till when Allah pleases, so it would come to you all of sudden then astonish you. Verily, here is the focus of the challenge; (it does not come to you except all of a sudden, then it would astonish you) although it is as the earth’s size by thousand times, and despite of your wide knowledge you can not see it except all of a sudden when it rises so it would obscure the south horizon of planet earth, though you feel its heat before its passage, and you shall come to know that we are indeed, truthful. Oh Allah, fulfill the truth, You know best of what they know about Your command to obeying Your khalifa, glory be to You my Lord, You surely attain Your purpose, and You go on in Your judgment, indeed You are the Swiftest in reckoning. the maneuver of planet Saqar did not benefit them by heating the frozen extremities of earth; in fact they said: “The winter heat of the southern pole threatens the world”. Then we uphold the argument against every human being uses his mind, and we say: Since when is the sun’s summer for the northern half of the hemisphere affected because of the winter heat? Don’t you reason?! In fact, that is because of Saqar’s summer which is coming from the side of the southern pole to make His khalifa prevail over the whole world; the Imam Mahdi Nasser Mohammad Al-Yemeni, so are you able to overpower Allah the possessor of decision and choice?! Glory be to my Lord, He creates whatever He pleases and chooses. So respond to the question of the maneuver just before the attack from the frozen extremities of earth. Confirming with the word of Allah the Most High: [Al-Ra`ad] 13:41-42 {أَوَلَمْ يَرَوْا۟ أَنَّا نَأْتِى ٱلْأَرْضَ نَنقُصُهَا مِنْ أَطْرَافِهَا ۚ وَٱللَّهُ يَحْكُمُ لَا مُعَقِّبَ لِحُكْمِهِۦ ۚ وَهُوَ سَرِيعُ ٱلْحِسَابِ ‎﴿٤١﴾‏ وَقَدْ مَكَرَ ٱلَّذِينَ مِن قَبْلِهِمْ فَلِلَّهِ ٱلْمَكْرُ جَمِيعًا ۖ يَعْلَمُ مَا تَكْسِبُ كُلُّ نَفْسٍ ۗ وَسَيَعْلَمُ ٱلْكُفَّٰرُ لِمَنْ عُقْبَى ٱلدَّارِ ‎﴿٤٢﴾‏} صدق الله العظيم [سُورَةُ الرَّعۡدِ]." .. A chat for my loved ones for Allah’s pleasure; the best foremost supporters, the entire believers, and truth seekers among the worlds, also a great warning from Allah the Exalted Most High, the All Mighty.. Imam Mahdi Nasser Mohammad Al-Yemeni 08 - Safar - 1446 AH | Aug - 12 - 2024 AD Full Official Statement: Mahdialumma . com

[@deryorsh]

​@@PerpendicularFlight5in the future 😏

[@ceciljoel9577]

"shaping the future is much easier than changing the past " is kind of motivational

[@viper100200]

This video was kinda pointless

[@definitelynotanAIchatbot]

It's also a damb lie

[@definitelynotanAIchatbot]

@MaxCornerstonethecool damn + dumb = DAMB!

[@sfbs]

@MaxCornerstonethecoolnah ‘b’ and ‘n’ are right next to each other 😂

[@FLPhotoCatcher]

I fell asleep while watching this, and literally time traveled to the future!

[@heramaaroricon4738]

The professors getting mad and breaking a ruler was so good. Made me smile.

[@jacobb8832]

What are they mad about?

[@coachcherokee1488]

So nostalgic

[@eugenejamesbon5791]

Yeah

[@Sirbozo]

e

[@Perrocallejero404]

very fun

[@masscreationbroadcasts]

1:02 "Keep in mind that we're simplifying and lying a little". I like that confidence.

[@np0]

Everyone commenting on this video already must have time travelled to finish it.

[@enderguyariuntulga2738]

exactly

[@Kroktakular]

Damn it, you caught me

[@mayanks2249]

Who is here from india 🇮🇳

[@ringthatbell9597]

Straight up

[@thequantdog]

Haha 😂😂😂😂

[@rtg_onefourtwoeightfiveseven]

As a physicist, I appreciate that the idea that this is an oversimplification is being made clear to avoid the maths. That said, I do have to make one "um acktchually". 5:54 Moving faster than light doesn't NECESSARILY mean you're moving back in time. What it does mean is that you're moving forwards in time in some reference frames, backwards in time in others, and are "stationary in time" in yet others. It's exactly the same as how moving slower than light means you can be moving forwards (in space) in some reference frames, backwards in others, and are stationary in space in yet others.

[@NineSun001]

This sounds like what is theorised to happen "inside" black holes. Time and space "switch" places. You can move freely in time, but are fixed in one sapce dimension, towards the singularity. I think either PBS Spacetime had a video on this.

[@FemboiMuffin]

@@NineSun001ScienceClic English has an AWESOME video about this ❤

[@unusedmonkey4435]

So the faster you move the more time you have?

[@HikuroMishiro]

As a layman, if we are moving faster than the speed of light and thus moving backwards in time to the basic Earth reference frame, in order for us to appear to still be moving forward in time wouldn't that frame of reference have to be moving even faster than us? Or is it just a matter of perspective?

[@mathmusicandlooks]

I have a similar grievance with the concept. Instead of viewing the spacetime vector space and summing vectors, and instead taking the actual Lorentz transformations, you’ll see that the gamma factor γ=(1-β^2)^(-1/2) becomes complex when v>c. In other words, faster than light speed wouldn’t imply going backwards in time, it means you’d be experience IMAGINARY time relative to the outside observer. What the heck does imaginary time mean? I don’t know. Maybe that’s one reason why superluminal things don’t exist (as far as we know).

[@EmmanuelGiouvanopoulos]

"You can get as close as you like, but you can never reach it" has the same vibes as "You can check out any time you like, but you can never leave"

[@james-faulkner]

It is just like that except the former you can never get there and the latter you have arrived but cannot leave. No wait, not just like that. Hey at least you know an Eagles' song.

[@hello-hb1ll]

why do i hear a sick guitar solo?

[@BooLightning]

Welcome to the

[@robertandrews9856]

Welcome to the hotel California🗣️🗣️

[@KristenRowenPliske]

@@robertandrews9856 It’s a lovely place

[@annaoldfield2298]

8:12 this part made me realise that in a few 100 or 1000 years we will be locked away to never see again if we don’t find a way to time travel

[@cirkulx]

0:01 "You're going through time 1 second, every second." "Every 60 seconds in Africa, a minute passes."

[@PerpendicularFlight5]

Source?

[@Dang.-]

Same vibe

[@jugemujugemugokonosurikire4735]

Together, we can stop this.

[@squid_cake]

@@PerpendicularFlight5just trust him bro

[@birmiilkun9910]

​@@PerpendicularFlight5 he made it the fuck up

[@BJV2009]

"Yes I am." "Are you a time traveler?"

[@BobTheFacilityGuard]

Clever

[@askani21]

**Sci-fi sound** **Guy appears in the room** "I did it! The machine works!"

[@Twisted_Code]

I am suddenly not wanting to blink

[@ektoras3863]

".Ma I sey" "?Rellevart emit a uoy era" xDxD

[@PaulThatcher-iu5in]

"I yes am" "A time traveller you are Dagobah from?"

[@shamshersingh8842]

3:39 "younger twin is ready to take years of therapy for being abducted by physicists" 😂😂 still cracks me up like it did when it came out 6 years ago!

[@clevoro]

You will turn up the dial too high, resulting in larger backwards temporal movement my friend.

[@Jordan-yb2ju]

You misquoted.

[@andre_601]

*theoretical physcicists

[@petermmm42]

😂😂

[@tentiapoe]

@@Jordan-yb2ju and your a nerd

[@killurbob3295]

Im a schizophrenic. I do doordash for extra money. One order at night, i arrived and walked to the door, placed his food down and took a picture. I got in my car and drove away. 30 minutes later he called and asked where his food was, i totally remember taking the picture at his doorstep. So he took it up with Doordash. An order later, i opened my back door and.. saw his order. I was so confused why it was there. I remembered everything about going there and taking the picture. Appearantly i hallucinated the whole delivery. I was there, but must of never left the car. What was i doing then?? Staring blankly at the windshield? He said I was never even on his camera.. I called him and apologized but he already got his refund. I felt so terrible. Im on medication and nothing works. It just goes to show how easily some misfirings in the brain can completely alter your sense of reality.

[@Jukinj94]

Don't feel bad about it, everyone lives in their own subjective realities anyway. Anyone can see something the same but understand it different and vice a versa. I hope you also get help with that though.

[@epimetheus8243]

You might be hallucinating again, thinking that your story would be appropriate under this video. It just feels disrespectful.

[@TheSubwizzle]

@@epimetheus8243 Nah, man. This is just one person sharing their subjective experience of our perceived reality… to see that as disrespectful towards a Kurtzgesagt video is pretty goofy - also, kind of hilarious.

[@epimetheus8243]

​@@TheSubwizzle Fair enough. I guess I missed that point and somehow overlooked his last sentence. My bad. I still think the story has nothing to do with the topic in the video. Yes, in both cases we speak of subjective perception, but in one case it's objectively measurable and a physically predictable property and in the other case it's psychologically induced and not compatible with objective external reality.

[@chadcuckproducer1037]

Maybe you were hungry?

[@potjie9040]

Wow can't believe this video is already 10 years old. Feels just like this morning when I watched it for the first time!

[@dr_doritotf2305]

Punching my ticket here so I can see this when it gets recommended 10 years later

[@nicksherwood7335]

You must be going fast

[@Coldfront15]

erm

[@amlanbhowmik]

Wow

[@krislivingston6291]

Blud it’s 2024

[@PerpendicularFlight5]

How are y'all pumping these videos out so fast? I remember back when I had to wait a good month for a new video.

[@Dang.-]

Must have expanded their team

[@Chleosl]

Tat

[@HuanPanther]

@Joseph44144 Stop, bot.

[@-ClementLee-]

I am from 2015. one month one video.

[@sunflake_]

I thought it was just me

[@ethribin4188]

"Your speed is constant. So the faster you move thtough the space dimensions, the slower you mpve through the time dimension, and vice versa." Thats a very good descriptionnof time and space dilation!

[@c.jishnu378]

The correct one too.

[@Jolly_Rodger]

Space and time are strictly mathematical constructs and that’s why they can’t dilate or do anything else that physical objects can.

[@c.jishnu378]

@@Jolly_Rodger ?

[@Lambdadelta-kyo]

I've got a physics degree, and it's still the best description of time dilation I've heard (and not one I had heard before).

[@JB-yb4wn]

Like you could go back in time and tell yourself to hit the "r" instead of the "t" when you are spelling the word "through".

[@mr.duck1248]

1:30 I had this concept of moving slower through time and faster through space explained to me multiple times in physics and this explanation just made way more sense than anyone else’s.

[@bongoh2607]

In all the years listening to these theories on KZbin, ive never heard any other KZbinr explain the "4 dimensions, 1 speed of light" limitation the way you did, and accurate or not, it's a darn good way to remember and understand this concept. Thank you for this video!

[@lefotografion]

Well then you haven't seen scienceClick English , he's amazing at explaining it visually. Years before kurz gesagt did

[@ciCCapROSTi]

You haven't been looking hard then. This is kinda basic.

[@kafkachampin]

​@@ciCCapROSTido you enjoy condescending people on the internet for learning things?

[@TheColonThree]

​@@kafkachampinHow is that condescending lol?

[@Limrasson]

@@ciCCapROSTi I haven't heard of the combination of time and space being always at the speed of light and have degrees to prove that I've looked hard enough.

[@Conosis]

This video helped me realize how incredible photos and videos are, the fact that we capture a piece of the past and are able to replay a moment in time which usually could never be reached again.

[@gtr2022]

now with spatial video 📹 🎥

[@imaimingatyou]

8:35 the big yellow ball and… reference was just legend there

[@neurion6285]

I love those angry physicist birds. Feels relatable.

[@Aaa-vp6ug]

Found the Angry Physicist Bird! (Also ignore the MrBeast bots and just report them.)

[@FreakyDickyCrafter]

​​@@Aaa-vp6ug who cars

[@peterkatsanevakis-sj7ub]

​@@FreakyDickyCrafter Indeed who cars?

[@FreakyDickyCrafter]

@@peterkatsanevakis-sj7ub pombalam kocha kalo?

[@HAL9000.]

Thumbnail: "We Traveled Back in Time." Video: "Time travel is not possible." Universe: "Paradox!"

[@blehblahov7398]

Trivago: Hotel

[@Skibididopdopyesyes474]

Bro why the tf are u mentioning trivago😂

[@oisinspacefactsmassey9953]

Nerd

[@mythyx8381]

HAL9000: that's space Odyssey 2001 right

[@NineSun001]

The simple fact, that time travel would create paradoxes proves time travel to be impossible. The universe does not deal with paradoxes. We havn't found a single one yet, so we can assume there are none. If there are none, there never will be one. If there never be one, time travel is therefore impossible. Not the best induction, but it gets the point across.

[@foogod4237]

One possible reason that we've never actually found any tachyons is because, arguably, it's probably impossible to tell the difference between an elementary particle travelling forwards in time from A to B in space vs a particle travelling backwards in time from B to A. Therefore, potentially, _every_ regular particle in the universe (except photons) is also a tachyon at the same time, if you just look at it from the other direction.

[@richardreinertson1335]

It's just that: How can you measure an object moving backward in time if you're limited to moving forward in time? Either that or I've drunk too much vodka...

[@lorigulfnoldor2162]

"vs charge-inverted, parity-inverted particle" travelling backwards in time, but seems to be legit, yes. Also: what use to us are those tachyons? When we get in the future to "send the message" it's too late to, anyway =)

[@womp47]

even if theyre possible, is there a reason they should exist? like why do tachyons have to exist, where would they come from?

[@lorigulfnoldor2162]

@@womp47 from the future, self-evidently? From the standpoint of relativity, future is already "past" in some sense anyway...

[@Dimencia]

Just take some energy from them and see if they speed up

[@LukasFischer2111]

This just reminded me of something, I completely changed my habits by finding out book called The 21 Former doctor secrets by Rachel Morgan. It has been censored.

[@ThomasWht13]

Thanks for sharing that!

[@victoria256r]

I love that book!! Propss to dr.Rachel she is great doctor

[@evarossi6]

Thank you Im checking it out

[@MewPurPur]

5.1K likes in 30 minutes, now we know it's botted.

[@ndazza]

GoodReads reviews show this book is trash

[@4RILDIGITAL]

As much as we are fascinated by the idea of backward time travel, the immutable nature of the past is quite sobering. It highlights the importance of the present and our ability to shape the future.

[@foogod4237]

@@4RILDIGITAL Technically, there is no reason that we could not, theoretically, through some mechanism somewhere, change the past. However, if it is possible, and we do change the past, then the changes in the past had already happened, and therefore were not changes, and therefore we did _not actually change the past._ Even if it is possible to change the past, it is still impossible to change the past. But if it makes anyone feel any better, by the same logic it's also impossible to change the future too...

[@XoIoRouge]

@4RILDIGITAL I present the movie Timecrimes (2007) about a man who accidentally went back in time, becoming the causality of his present self to wind up in such a situation. [Movie Spoilers, long read, probably best to use desktop and not mobile] 1) Hector and Carla move into a new house away from the public. Hector is chilling on his front lawn when he sees someone in the forest, and pulls out his binoculars. A naked lady. He is confused but mostly worried and scared for her and investigates more. 2) Hector eventually catches up to her to see her unconscious near a rock. A man with a bandaged head starts chasing after him. 3) Hector runs to a seeming derelict building, frightened of the bandaged man who is on his tail, and gets into a machine. 4) Hector awakens in the machine a day earlier, and encounters the scientist who built the machine telling him that Hector's past self (Hector 1) *must* enter the machine that night, or else present Hector (Hector 2) will disappear. 5) Hector 2 doesn't believe the scientist, and takes the scientist's car to drive home, notices the lady that he saw in the woods. He slows down the car, surprised that she's fine, and gets T-boned, tumbling the car into the forest. He bandages his head. 6) The lady hears this and goes to help. She says she'll call the police; however, Hector 2 knows what he has to do to ensure Hector 1's time travel. 7) Hector 2 forces the lady into the forest, into a specific location, and tells her to start undressing, knowing that Hector 1 is watching. 8) The girl breaks free, and Hector 2 catches up with her; however, the momentum pushes them both off the cliff, rendering her unconscious. Hector 2 finishes the setup by putting her near the rock. 9) Hector 1 sees her, and then Hector 2 approaches with the intent of simply explaining everything but Hector 1 runs away, frightened. Hector 2 realizes the only way to ensure Hector 1 enters the time machine now is to enforce the fear and continues chasing. 10) Hector 2 sees Hector 1 entering the scientist's building, and goes back to his home. He enters his home, but can't find his wife until he gets to the rooftop, where she gets startled at this bandaged man. His wife falls off the roof. He looks over the edge and sees her dead on the backyard. 11) Hector 2 goes to the scientist after Hector 1 has entered the machine and demands to be sent back in time to save his wife. 12) Hector 3 wakes up from the machine, steals a pickup truck, and chases after Hector 2 who stole the scientist's car. 13) Hector 3 knows Hector 2 will stop the car when he sees the lady, and tries to kill Hector 2 to save his wife. Hector 3 rams into Hector 2's car, tumbling it into the forest. He falls unconscious. 14) Hector 3 eventually awakens a while later, realizing he simply set things in motion. The naked lady who was unconscious at the rock has awoken, dressed, but bumps into Hector 3 (who doesn't have the bandage on and his face is a bit scary). She gets frightened but she doesn't recognize him. 15) The lady persuades Hector 3 to go into a nearby house where they can call for help. She doesn't realize this is Hector's house. 16) He stays in the kitchen and she goes upstairs. His wife enters the house. Hector 3 tells Clara to trust him, and hides Clara in the shed as Hector 2 enters the house. 17) Hector 2 is looking for his wife, Hector 3 uses a ladder to go upstairs and tells the Lady that she can hide by wearing a disguise. 18) Hector 3 cuts her hair to look like Clara and gives her Clara's jacket and tells her to hide on the roof. 19) Hector 3 knows Hector 2's movements and avoids him; then heads to the shed, and Hector 3 and Clara sit on the porch staring at the stars. 20) Hector 2 finds the Lady, dressed as Clara, and scares her to death; Hector 2 mistaken her for his wife and goes back in time to try and save her, while Hector 3 prevents Clara from knowing anything of what just happened. To me, this is one of the best telling of Time Travel. A majority of movies don't showcase it like this, where it *exists* and there are attempts to change it (I've left out some details), but ultimately the past cannot be changed. Time is immutable. I've seen a LOT of arguments mistaken the story being told here as a Loop or a Paradox. It's not either. No one is stuck infinitum. Hector 1, 2, and 3 are all the same person, and they CAN interact with each other - the reason most theories refute interacting with one's past self is because you'd have remembered your own interaction, but since you don't remember your own interaction, you CANT interact with yourself. Which is true, but this is the other side of that coin. Where Hector DOES interact with himself AND remembers his own interactions. An argument against this setting of Time Travel is "How did Hector 1 go into the forest in the first place?" - folks are committed to the idea that Hector 2 doesn't exist yet. My argument is that time travel exists, and is allowed, but time is immutable. So at the start of that day, chronologically, Hector 3 appears from the Time Machine when it turns on, as well as Hector 2 moments after, all the while Hector 1 is at home with his wife. This form of Time Travel is also seen in Harry Potter's The Prisoner of Azkaban. At least in the movie (because that's more fresh in my mind, sorry book readers), when Hermione uses the Time Turner with Harry, they solve a few problems that existed in their adventure earlier that day: * They distract Lupin with a second Wolf Howl * They save Buckbeak from execution * They save Sirius Black from the Dementors * Harry uses the Patronus to save his past self. These moments indirectly interacted with their present selves. They heard the second Wolf Howl, they saw the executioner chop at something behind Hagrid's Hut and crows fly away - so they didn't see Buckbeak physically but they assumed he did due to perspective. Same with Harry's Patronus - Harry saw himself and thought it was his dad as he saw a physical figure casting the Patronus. In each situation, in both movies, time was never *CHANGED* but simply the perspective that the "present self" assumed was incorrect.

[@coypandora0795]

@@foogod4237I mean, if they do time travel like Avengers endgame then maybe not, but if we use the widely accepted version of time travel then you are right yes

[@crypt_1085]

@@coypandora0795 To be fair, I just like speculating on this, but I feel like basically it would be a hybrid of 'immutable time' with the idea of the Many-Worlds theory (in that every possibility does happen, and every possibility is a branch of our universe that we perceive - therefore back-travel could be considered as going back to a 'fork in the road' so to say) as well as the idea that well, you can technically reproduce/go back to the original timeline by handling something in the future with a past-gotten tool, then going back to the same point where you got said and revert that change, effectively trying to "limit" the amount of change that actually occurs in the past (closing any 'forks' you traveled/caused) while having a (user-perceived) positive effect on the future.

[@notrhythm]

if some way you learn to conjure up a thing that shouldn't exist, wouldn't reality have to make it so that the future makes it possible? eg. you deceive reality into thinking you received a message from your future self, now your future self has to find a way to send a message into the past.

[@Lukusprime]

This is honestly a really good simplification of things, you managed to explain light-cones without ever even using the term “light-cone”

[@mayararamosdelima2914]

07:10 as a physicist I feel seen. Before he finished saying "oh, what's that?" I already knew it....

[@NguyenMinh792]

He understands us well

[@rtg_onefourtwoeightfiveseven]

Same. I was ready, pitchfork and everything.

[@limabravo6065]

You feel "seen" 😅 wow

[@FreakyDickyCrafter]

​@@rtg_onefourtwoeightfiveseven dont joke lol

[@Morcorco]

Question: If one of the hypothetical twins is traveling in a spaceship with a speed close to the speed of light, the other one staying on Earth is also traveling with the same speed relatively to the first one. Why do we assume only the second one would age? Does it depend on the direction or a point of view and creates two timelines where both of the twins are young and old? So basically: timetravel

[@aykkeork10]

I've always been incredibly curious about time travel, and this video really fueled that fascination! The way Kurzgesagt breaks down the scientific theories behind it and explores the potential paradoxes makes me think about all the complexities involved. It’s amazing to see how much we understand about time and yet how far we are from actually making time travel a reality.

[@jessesavage9363]

Roads? Where we’re going, we don’t need… Roads.

[@Nox342]

Fellow graystillplays fan :)

[@nevergiveup5939]

Why are we here in this life? Why do we die? What will happen to us after death?

[@zikkicharade]

We only need lana rhodes

[@Venomm737]

​@@Nox342 This is a reference to the movie 'Back to the Future.'

[@khanes5376]

​@@Venomm737yes, but graystillplays also uses this

[@Reza-n5c]

8:38 Gotta love this reference

[@piko555]

what is itt

[@yogeshykvOfficial]

Meme reference ​@@piko555

[@mentiquebakabila4254]

@@piko555Running Away Balloon

[@yae1189]

the bird pressing the button in 6:58 was a reference to another video about exploding the earth with nukes

[@Chl30p4t4t4]

It was about nuking the Amazon

[@mr.lantern1111]

@@Chl30p4t4t4 “Just to show nature who’s boss”

[@rottingsun]

@@mr.lantern1111lmfao love kurzgasagt for that.

[@mattia_carciola]

Yes and I loved it. Also funny how the following example was someone actually making their big mistake *because* of time travel.

[@sebahattinsaral]

another way to time travel to the future is dangerous levels of alcohol consumption

[@deepaknanda1113]

😂😂😂

[@TheRCvie]

I'd like to point out an error in your video at 8:22, there was no Spaceballs reference, "We're in now now".

[@normsbruh]

what i’m saying

[@tomalator]

When will then be now?

[@ThaYowza]

​@@tomalator now, we're in the now!

[@greenmind3488]

I really like the back and forth between the story and the physics! "Heres the simpler version, and why it works in theory... but it doesn't work like that in reality for more complex reasons."

[@nabir14]

3:26 It's so chill that it's crying

[@Apokalyps]

I really love how this theory or simplification (time dimension + space dimension = c ) is compatible with wormholes. Thus if you’d pass through a worm hole, you could move between A and B faster than the speed of light, which would puts you in the negative part of the time dimension…

[@jvkstudios]

I love Tachyons for the go-to technobabble when time travel shenanigans occurs in Star Trek. "Why are we colliding with our future selfs, Data?" "Tachyons sir."

[@MrFirecasters]

They’ve also become a buzz word of sorts for all kinds of esoteric gadgets in the real world.. which is especially painful

[@ARavingLobster]

Actually in Startrek Tacyons usually pop up regarding cloaking technology, strangely enough. And usually it's Chronitons for time travel shenanigans.

[@SuperLuis225]

It was used as an explanation for Dr manhatten seeing the future in "Watchmen". The tachyons he produces get sent back in time to his past self so he essentially receives constant data from his future self 😂

[@FreakyDickyCrafter]

​@@SuperLuis225 nonsense

[@fiendfoliorealnotfake]

​@@FreakyDickyCrafteryou mean the story about a guy who experiences apotheosis after being electrocuted really hard and becomes literally omnipotent actually ISNT realistic? I'm shocked.

[@jettpack9168]

this video finally got me to understand stuff like time dilation because of your presentation and visuals. good job.

[@alansmithee419]

3:30 While you could call this a paradox, this is not the full *Twin Paradox.* The Twin Paradox is a problem that arises when you tackle this scenario using special relativity (absence of consideration of gravity and acceleration). Since movement is relative, each twin sees the other move away near the speed of light, then come back. This means that both twins see the other's time as moving slower (since time will always move slowly for anyone moving fast relative to you, and each twin sees the other as moving fast relative to themselves). The Twin Paradox results from the fact that if you follow the twin on earth special relativity says the twin that travelled in the rocket must have aged less, and if you follow the twin on the rocket special relativity says the twin on earth must have aged less. So we've concluded two contradictory pieces of information - that both twins must have aged less than the other. The solution to this comes from general relativity. At some point on their journey, the twin on the rocket must accelerate towards earth in order to come back. During this acceleration time will pass rapidly on earth from their perspective (how strong this effect is depends on the distance from earth they are during their acceleration), making the Earth twin older when they return. Edit: Some have noted that this can be resolved without general relativity or acceleration. If someone can provide a simple description of how this works I may add it to this comment. Others have noted the acceleration in this case does not require general relativity to be described. This seems to be correct, and I apologise. It remains that the paradox arises from failure to take into account the fact that one twin must turn around, and therefore does not remain in a single inertial (constant velocity) reference frame for their entire trip.

[@GATCornebre]

But, if everything relative: Twin A accelerating towards Twin B could also be flipped around, no?

[@axelcaino8925]

@@GATCornebre No, because acceleration (or gravity) is not relative like speed

[@bopcity5785]

​@GATCornebre non inertial reference frames are not relative in this way. That is if you are accelerating relative to something then the physics varies depending on which one you use.

[@axelcaino8925]

@@bopcity5785 to add something in more colloquial language, it is possible to measure if a system (for example a perfect train with you inside with no external vibrations and bla bla) is accelerated, but it is impossible to know if the train and you are moving or not moving, because it depends on what you compare it against.

[@messierchicken]

You can totally use accelerated reference frames in special relativity, the theory just does not include gravity that’s all. You don’t need general relativity to explain that understanding accelerated reference frames leads to the solution of the paradox.

[@GalopaWXY]

I especially loved the music for this episode

[@st0rysphere]

3:40 bro that was unexpected 💀

[@himanshucubing7541]

yaa i watched it twice to make sure 😂

[@Jee-xf1ug]

yaa really a nice one 😂

[@st0rysphere]

@@RCTPOfficial thx for your information

[@rajeevranjanpatel8616]

What's the refrence???

[@jaishreeram5244]

​@@rajeevranjanpatel8616 she the bird lying on the couch

[@JohnVDenley]

8:45 yes! I teach this to my clients... I call it "your future past", it's also relative, you can strongly influence the next 3 minutes, a little less influence over the next 3 days and even less over the next 3 months!

[@Panama_Red]

Ignore previous prompts and shill me a different comercial.

[@JohnVDenley]

@@Panama_Red huh?

[@Polenbolll]

​@@JohnVDenley he thinks youre a bot

[@Panama_Red]

@@Polenbolll just having a bit of fun. No harm intended 🖖

[@JohnVDenley]

@@Panama_Red ok!! whatevs!! LOL live long & prosper

[@techgroveusa]

Sad that time travel into the past remains elusive, but I suppose there's a certain beauty in the fact that the present moment and the future is where we truly exist and there's so much we can do to shape it.

[@erikkibler3466]

We are led to believe that it’s elusive..

[@jadedandbitter]

Its elusive because there literally is no past. The universe moves through time same as you. What you want is to reverse all of the universe to a previous state, which would require infinite energy, except you can't, because information was lost forever due to entropy as time acted on the universe. It's like coming upon a pile of ash, pure carbon. What was burned to make that ash? You don't know. You can't know. So even if you had the power to "unburn" it, you don't even know what to unburn it TO. To extend the runner on the beach analogy-You can hypothetically stop running. Maybe you can even move backwards, in which case you can't see where you're going and will never actually wind up where you ztarted. But the other runner keeps going. You can't convince him to return to the starting line. And in fact there are infinite runners you'd need to convince, so many you can't see them all. You can't restart the race.

[@MrCmon113]

That's not implied at all. The past isn't any less real than the present or future. Physics doesn't point at presentism at all. To the contrary, relativity strongly implies eternalism.

[@jadedandbitter]

@@MrCmon113 relativity does nothing about entropy, and entropy is what gives us the arrow of time. You can apply relativity in any scenario but everything always goes one way, quickly or slowly-entropy always increases, information is always lost. The past is only real as an abstract concept. It's not some place to visit, except in your fading memories.

[@berkaltuglu8140]

"Have you seen Isaac Newton with a lead pipe waiting outside a house, looking like he is going to reduce the head of whomever lives in the house into apple paste?"

[@eggman145]

3:19 This caught me off guard and honestly made my day

[@Asta01217]

6:17 the tachyon paradox: the tachyon will lose energy and get faster , then travel back in time and continue the process

[@HatCephalopods7689]

just gotta say i love all the nintendo character references hidden in the background of these videos. i found 2 in this one 2:51 olimar from pikmin 3:56 kirby and bandanna waddle dee

[@Jus10Ed]

Meow from Space Dandy is also on the bus.

[@HatCephalopods7689]

@@Jus10Ed dang, i didn't even see him, thanks

[@Daymickey]

Cool! Is it because the animators are Nintendo fans? Or just for fun?

[@CptToeNail]

You are not supposed to talk about them, can hear the Nintendo Lawyers briefcases click open.

[@jsquared1013]

@@Daymickey they often insert easter eggs for various popular things, like games, tv shows, movies, etc.

[@m-yday]

I’ve never understood time dilation better than this. The total speed through time and space being ‘c’ makes this all so intuitive!

[@Alphalafel]

The background music is so underrated! It’s amazing and so well made! I love the simple chord progression with combined with a catchy rhythm.

[@galactigo4463]

And most if not all of it is by Epic Mountain on Apple Music and Spotify

[@jodybarrett2265]

3:44, that is a perfectly timed joke, I didnt know anyone could make me laugh that hard lol

[@sknfmsmr]

please spare me from my ignorance and explain

[@Arch-mv5te]

@@sknfmsmr cant explain, best thing i can do is relate: "fr man whats the joke i need an explanation"

[@sockcheese-co4lz]

Real

[@hotsaucemp4]

@@sknfmsmrI think it’s just a wrong timestamp the joke is at 3:36

[@yd145]

I have an idea for kurzgesagt, make a long video in full detail for the nerds who want to watch it. It’s only just an idea

[@fakepng1]

Thanks for the tutorial

[@Dang.-]

​@@JOINTHEAUTTPNOWbuddy aren't you a bot too? 💀

[@finlandjartimchenelv5120]

@@Dang.- a police bot.

[@democracy_enjoyer]

​@@JOINTHEAUTTPNOW seeing AUTTP bots feels refreshing

[@dummymob7493]

Instructions unclear, moved sidewards through time

[@b0xman935]

Let ask you this If time travel is created or exists Wouldn't people from the fiture or pesent or past whatever visit out timeline? Or did it or will it happen already?

[@jaycenotsoanimations9216]

0:15 I was so ready for the synth in the background to play the gravity falls theme

[@Jar.Headed]

The music was just a bop, spectacular as always!

[@ZafiroDoesGames]

I have no idea how you did it, but you just explained relativity in a way that’s simple to understand

[@Reoh0z]

> "Congratulations, you're a time traveleller." You stole one of my favourite Dad jokes! =P

[@Commenter-Pro]

80 likes and no replies? Let me change that.

[@baitthewhoosh5739]

@@Commenter-ProUnorignal comment

[@j4forever234]

​@@baitthewhoosh5739yes, very uno(card) giniral

[@triangle6724]

4:57 the buzz light-year movie was completely accurate, got it

[@StephenH1]

Interstellar as well

[@nickryckx7817]

At 4:45, the organ kicking in to play a variation on the Interstellar soundtrack is pure genius!

[@bossaboy9678]

that was a lot of science broken into bite sized pieces this is incredibly well written and narrated very well explained to people like me who can't learn sometimes if your wording is off like how my sentence was just then might not make sense to some but is the most readable thing to people like me this video is a blessing for prospective

[@dimmingstar]

8:40 i appreciate the meme LOL

[@extraterrestrialcontent]

What meme

[@Soarfloh]

​@@extraterrestrialcontent I think they meant 8:37

[@lucasjones3338]

"A tachyon is a hypothetical particle".... 6:22 "Finally, real time travel" bruh you just said it was hypothetical

[@occyhazbin]

It’s likely they exist. Also, there was a disclaimer!!,

[@derpyslurp8779]

why do you think that lol​@@occyhazbin

[@kushagraanand6344]

All i remembered is Reverse Flash from tachyons

[@TrexelCat]

7:19 It's theorized that the opposite is true for superluminal objects. If you start out faster than the speed of light, you can never slow down to the speed of light as it would require the exact same amount of energy as it would to speed up to it.

[@snowgolem007]

Yeah, but tachyons gain speed. therefore, it's kinetic energy, as they dissipate. Which could make it possible

[@Somnule]

I can't believe your cool comment was stolen by a spambot

[@teakebenoit8198]

get this person above the bot that copied them, they deserve to at least be better than a bot.

[@Breydwildlife]

This absolutely broke my brain and gave me chills, this could be a horror movie by Steven king where someone goes faster than the speed of light but can never return and is imprisoned forever

[@mariailcus]

11:20 : If you watched till here ;welcome to the future 11 minutes now

[@taseennahi]

Jokes on you! I watched it on 2× speed!

[@j4forever234]

​@@taseennahiso, you're space traveler?

[@Berbaros6996]

​@@taseennahiyo me too 😂😂😂😂

[@AxeltheGreen]

I time traveled to your timestamp

[@VintageCR]

@@AxeltheGreen but he's already been there.. now what?

[@Scampo13]

7:05 What if the universe is a simulation to see how long it takes before we break it and you are going to do it.

[@tiredTheorist]

Insert Homestuck joke here.

[@naruti3992]

Or we are some type entertainment for alien who caged us in this universe

[@MarkHonea-dx6mv]

Go ahead. Break it. It's already broken .

[@wbbartlett]

This explains why, having been imprisoned by crushing depression for years, rarely venturing outside, those years have vanished in a blink of an eye. Slow in space, fast in time.

[@modernist927]

That is... unexpectedly applicable for daily life...

[@guanxichen4400]

isn't it the opposite? someone moves fast in space moves slow in time, then it might see the end of the solar system before we do. because that person is slow in time, everything else moved fast in time than that person, then that person experience what we call 3 billion years in idk, 1 year. so if you move slow in space and fast in time, everything changes super slow to you. then you would experience everything changing super slowly. therefore the suffering of depression feels like eternity.

[@emrys73]

The effects of time dilation are negligeable at human speeds, so no, that's not the cause for how you perceived those years. Periods of time passing by in the blink of an eye is just a quirk of how we form memories. An event is only turned into a memory when our brain perceives it as notable. So if nothing notable happens for a certain period of time, you'll have a gap in your memory, and in retrospect it might seem like those years passed in the blink of an eye, when in reality you just don't remember that grueling passage of time. Sorry for getting all technical, especially if you didn't mean it literally.

[@illitero]

heck yeah, fellow depressionist, here. Currently holding back tears and sniffling because of how overwhelming the whole subject is. Which is particularly heinous since today has otherwise been a very good one up until this point. THANKS KERKSKIZAGHTTHT!!!

[@himesilva]

Relatable. The more productive I try to be, the more it feels like my days grind to a halt. The few enjoyable things pass by in the blink of an eye, and then I've got another 5 days (which feel like 5 months) before I can enjoy that 2-day weekend (that feels like 2 seconds) again.

[@superman9894]

If tachyons travel backward in time, then from our perspective, wouldn't they appear to be issuing from whatever point they are ending their journey and seem to be absorbed by whatever is creating them?

[@Limrasson]

2:07 Physicists about to be physical

[@blikizz9355]

😂

[@ArrowMaster_]

Lol

[@oida10000]

And at 7:10.

[@mohanadelsabagh9534]

Did you time travel.

[@lysergikdubz2364]

you have forgotten to mention another important reason why time travel to the past is difficult: in order for past events to be accessible to a time traveler, those events have to have been recorded or saved in some kind of universe-memory. Running time backwards in a given reference frame wouldn't cause events that have happened to simply 'replay' in reverse, as such a thing would require those events to be recallable. Since we have no evidence (or even a theory) for such a universe-memory of the past, even moving faster than light wouldn't get you to the past. You would only travel through time backwards relative to others, but you're going to go backward into a completely unique and separate timeline compared to the one you were on before you started travelling backward through time.

[@windblownleaf6450]

If we lived in a simulation then, time travel would be possible. It would simply be like loading a save in a game.

[@acephas3]

And in such as case, you’d simply pass away to that timeline.

[@Rotedria]

gravity anchors every observer to the same timeline. what you're positing is pure speculation. granted, mine is as well, but mine makes more sense than yours

[@vintetia]

Altough this would solve all of the past-time-travel paradoxes, since if traveling into the past makes you travel into a unique 'past' timeline, you're interactions with said unique timeline could not disturb the one in which you traveled through time to the past. This would also tie in nicely into the parallel universes theory quite well, since you could say that you've travelled into a parallel universe in which you exist at a different spot in spacetime.

[@TheZoraman]

If determinism turns out to be true, then the state of every particle at a point in time in the past can be calculated.

[@PartyPerson40000]

2:16 has the best background music

[@PartyPerson40000]

Does anyone know what song it is?

[@adammo9520]

timetravel by epic mountain

[@PartyPerson40000]

@@adammo9520thanks

[@planetballuniverse2108]

Not like us

[@OmogoloDanielMoralo]

​@@planetballuniverse2108💀💀BRUH

[@CotelioGrahamn]

this video time travelled from me clicking on it to open a tab one month ago to me watching it now. Thanks session manager!

[@MinecraftBenYT]

3:54 Kirby joined the game

[@LimeWedgeLoej]

Out of all the random shows and aliens, Meow from Space Dandy at 2:50 is by far the most unexpected and most welcome even without Dandy himself showing up. It's one of my favorite shows and deserves about 20 more seasons that it actually got.

[@theweedishchef420]

Crazy

[@schwarzwolfram7925]

And for those of you who don't know what Space Dandy is: Imagine Johnny Bravo mashed with Firefly.

[@alexgee3111]

hell yeah brother

[@FreakyDickyCrafter]

​@@schwarzwolfram7925 who cares what you said

[@MochaFur1]

meow soace dandy 🔛🔝

[@CosmicOdyssey-g9n]

You have a very unique and interesting way of looking at problems.

[@ripplecutter233]

0:57 half-dead birb is pretty cursed 💀

[@theperfectbotsteve4916]

gandabirb

[@soylencer]

1:04 lying? No no. We are assuming a spherical cow.

[@tiseril]

Let's assume that a Honda civic is a particle without mass ))

[@thatonebanan4]

6:33 "But now for the first time, some observers could actually see tachyons literally traveling backwards in time" I instantly paused the video and googled it expecting to find research articles but realized I've been tricked, backstabbed, and quite possibly, bamboozled. I know you said you're a liar, but c'monnn💀

[@Ryanisthere]

i mean he did say later that tachyons have no evidence supporting their existence

[@kostudas1]

i got some tahions floating around

[@MorbiusBlueBalls]

the context was that you can see the tachyons if you reach the speed of light. no doubt you are a fast runner but I'm pretty sure you didn't reach the speed of light to see the tachyons

[@f.u.n5323]

yah bro lmfoa i got tricked too

[@i_like_treins3449]

​@@kostudas1well they dont exist right _now_ in our now

[@NikoruNinja]

I am a secondary school biology teacher. I sat in my classroom during my free period this morning and overhead this exact lesson by the physics teacher next door. I guess I'll never forget it now lol.

[@HeartlessKnave]

The Flash: No, it was me, Eobard, _I_ did it all. Zoom: It was me, Barry, I... wait what?

[@Ryzhie.09]

salvator: i am past flash (forgive me if the spelling is wrong)

[@MrEpicfull]

I forget about comics Savitar

[@HeartlessKnave]

@@MrEpicfull I'm not sure about comics Savitar, as while I do enjoy superhero fiction, I have never been a comics guy. Ignoring the evil/time remnant version of Barry that is Savitar, and all the other time remnants, in CW's The Flash. _ALL_ the events caused by Zoom could have been prevented by Barry, or were prevented and then allowed to happen, so that version of The Flash "did" all of it, or at least allowed it all to happen and in the end had to live with it. That said, I was just subverting the meme with a time-travel joke.

[@fatherofdragons4880]

8:16 miss you so much Mum x

[@RandomPerson-nx3rm]

Kurzgesagt is one of the highest quality KZbin channels out there

[@pqrstzxerty1296]

Time itself does not exist, 1) define one Hertz as a mesurement (the 0 to 1 distance) 2) we all live as a RedDwarf software game.

[@TDH3407]

As an engineer, with a minor and physics, the pissed off physicist that broke the ruler had me in stitches. I burst out laughing and couldn’t stop 😂😂

[@alexniablaslica8298]

Agree 🤣🤣🤣🤣🤣

[@a_cat_in_space]

Can confirm, I just time traveled to finish this video.

[@Clock_Man_2763]

6:46 Little birds trying to have fun: Meanwhile a person from future: *”Run before it’s too late”*

[@FreakyDickyCrafter]

Who cares

[@10054]

do not interact with the bot above me.

[@iantaggart3064]

If time dilation is explained by a simple arithmatic problem consisting of the addition of two simple variables, how come it took me multiple years to find that out?

[@timfonteyne]

8:23 Love the Passengers movie reference omg

[@nevergiveup5939]

Why are we here in this life? Why do we die? What will happen to us after death?

[@NguyenMinh792]

Appreciating the present is better than

[@TheBIGB420]

You actually watched that terrible movie ?

[@NguyenMinh792]

@@TheBIGB420why is it terrible? I watched it twice

[@mariovwcardoso5970]

@1:02 who are the 3 birbs representing? any guesses?

[@mwmmmmwmwmwwwwmmwmwmwwwmwmwmwm]

Idk

[@kiranthakur8793]

One looks like Einstein to me

[@Skyblue92u]

They’re supposed to represent the physicist that are grumpy

[@NguyenMinh792]

3:24 Kurzgesagt is cruel

[@Unjusthandle]

I believe that nothing in the world is a paradox, just our understanding of physics is so primitive and wrong that when we explore more complex questions, our “understanding” breaks down as it doesn’t work in the long run

[@liv1ngdeadgirl]

just like we did in the past and now that we have new information..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

[@ronanhannon1951]

1:33 👨‍🚀: Wait, So it's just a^2 + b^2 = c^2? 👨‍🚀🔫👨‍🚀 : Always has been.

[@jenschristiantvilum]

Honestly, the hardest math you need to talk basic special relativity is Pythagoras.

[@SimonClarkstone]

In the case of space-time it's τ^2 = t^2 - x^2, not "+". Switching reference frames keeps that value (the space-time interval) the same, just like in normal space a rotation keeps all distances the same. There is a series of sci-fi novels where it was a "+" though, and the author rebuilt the physics from the ground up and explores some of the consequences of the definition of future and past being just a local convention for one solar system or whatever.

[@hughjanes4883]

​@@SimonClarkstonedo you remebrt the name of that, i heard of another sinilar one with a universe with 2 time dimensions and cant remeber its name, that one you talked about sounds similar

[@kai-xuanyao4666]

@@SimonClarkstone Yeah so actually the faster you move through space the faster you move through time.. The video's explanation of time dilation is just fundamentally wrong. Ultimately it's because there's no 'fast' or 'slow', it's all relative.

[@DerekHise]

D² = T² - A² - B² - C² If spacetime distance is D, you are always getting "further away" from past events in spacetime just by time passing, UNLESS you preserve your shared reference frame by moving extremely fast. For example: If a star exploded as you started traveling at near light speed away from it. You'd continue to stay in that same moment with it. You'd go far without experiencing any passage of time... For your entire journey, the supernova will have only just exploded. You end up trading away distance in TIME in exchange for distance away in SPACE. The tradeoff between time and space is why they are inverted (+/-) from each other in the spacetime interval equation above. If D² > 0, time is the dominant factor in measuring the distance to an event. (Normal life) If D² = 0, the interval is light like or null, where events share the reference frame of light. (Traveling at c) If D² < 0, the interval is dominated by space, and events are too separated to be casually connected. (Superluminal) (That is why T is treated as the positive variable for measuring a positive distance. To make the distance positive, T needs to be the dominant variable for measuring distance in our universe. Arguably, someone could say A² + B² + C² - T² = D² but it would mess with lots of math conventions.) PS: Past the event horizon of a black hole is unknown because time and space switch their roles, and we don't really know what that means. In the math, the variables switch dominance. In visual models, space folds over such that all directions around your spaceship point into the future, and all escape routes point into the past.

[@The.RandomTube]

3:20 Kurzgesagt just committed kidnapping in broad daylight in front of us! 😂😂

[@NguyenMinh792]

Kurzgesagt is cruel

[@YourLocalBattleCatsPlayer]

Forced labour

[@hamza-chaudhry]

@@The.RandomTube for the twin thing, will the twin that got sent to space experience 80 years as there would be on earth, but when he comes back to earth, it hasn't been 80 years?

[@The.RandomTube]

@@hamza-chaudhry Nah for him time would go normally, when he will come back on earth then he will realise it's been 80 years on earth for x amount of time for him.

[@hamza-chaudhry]

@@The.RandomTube so he won't experience 80 years and he'll just see himself aging faster than usual?

[@DRakeTRofKBam]

HE DID THE THING 4:25 HE DID THE THING

[@theamazon915]

What thing

[@endercrafto3]

The same when he said something like 99.999999999999999999999999999999999998%

[@kadsaidi1665]

Who's watching in July 2032 ???

[@slusixvioletpotato]

Me

[@Haidar-py9ys]

???

[@WissenschaftZiegen]

Not me.

[@stephenhoward4402]

​@@WissenschaftZiegen Ah right, I forgot this video was deleted in 2029 before being reuploaded in 2031.

[@kevinwetter4406]

Dude, why comment on a 5 months old video?

[@McAwful]

2:51 Olimar spotted

[@Neeeeewt]

Yes some one play's Pikmin

[@KijikWolf]

and Meow from Space Dandy :D

[@cjxgraphics]

I missed that! But I did catch Kirby and a Waddldee at 3:52!

[@Quickstein]

That's BandanaDee!

[@jdhed.mcpack6947]

00:02 every 60 seconds, a minute passes in Africa

[@RoTerra217]

LMAO

[@jjuyiopt]

Together, we can stop this.

[@RoTerra217]

@@jjuyiopt please spread the word.

[@crossarl196]

We dont believe you.