Neil deGrasse Tyson Explains Time Dilation

[@MambaBreezy24]

"If you can't explain it simply, you don't understand it well enough." Neil does it effortlessly. Amazing video.

[@R3_dacted0]

Well, either that or your language skills aren't very good.

[@satisfiedcustomer]

You call that explaining it simply? I mean granted he broke it down pretty good anyone here watching this I think is a niche audience and is probably able understand it a bit better tho. But I'd say even this breakdown is far from simple for everyday folk.

[@taviangaudiuso9078]

@@satisfiedcustomer yes and no. it is for a specific audience but he broke it down in simple terms RELATIVE to that audience. you could even say to anybody with his particle accelerator example that the faster u go approaching the speed of light the slower your time is relative to others

[@edwardlewis1963]

Time is LOCAL.

[@whydnot]

That was explained very poorly.

[@MarkB-vp9ki]

To me, the craziest thing about this is how Einstein conceptualized these theories in his time. I wonder how much different things would be today if he had never lived and we had to wait 50 years for someone to come up with these in say the 1950's or 1960's. Einstein is the GOAT in science without a doubt.

[@callanc3925]

Its really crazy how much stuff he predicted so long before it could be physically proven

[@valueofnothing2487]

It's actually easy. If you use the Pythagorean theorem and compare two reference frames, and then allow the speed of light to be constant, you get time dilation. Einstein didn't even invent this, but Fitzgerald and Lorentz did. What Einstein did was to have the courage to see how this could affect everything - nobody wanted to go there or think about the implications. In fact, they used all their energy to come up with some alternative explanation that did not seem so insane.

[@jadonplox]

cough isaac newton cough

[@Draziell]

Maybe today he would just be playing videogames...

[@silencionomus]

It helped a lot that he wasn’t scrolling through KZbin comment threads. What? Oh! Oops!

[@Nigelrathbone1]

No matter how many times I hear this explanation I still can't wrap my brain around it.

[@Horny_Fruit_Flies]

The closer to the speed of light an object moves, the slower it appears to be moving through time (aging) to outside observers... and the faster the outside observers seem to be moving through time (aging) to that object. Another way to look at this, if you looked through the window of a spaceship moving near the speed of light, the outside universe would seem to be moving on fast-forward like a VCR. And if outside observers through a telescope peered into the window of that space ship, you would appear to moving in slow motion. Now light (photons) move AT the speed of light, so to outside observers photons are frozen in time. They don't age, they are the same age the moment they were created as when they have traveled 1 billion light years. And from the photons' perspective, the universe moves through time at infinite speed, so in the instant the photon is created and then destroyed, the universe ages instantly. A photon created shortly after the Big Bang and flung into deep space experiences the birth and death of the Universe in the same instant. Basically, photons are outside of time, time doesn't seem to apply to them in any meaningful way.

[@sleepwith4098]

whats about the heartbeats? Does that remains same?

[@Horny_Fruit_Flies]

@@sleepwith4098 From the perspective of outside observers the heart would beat in slow motion, the heart beats of outside observers would seem faster.

[@techknowledge3911]

Great!!! It's not just me. I start off paying close attention to every word and detail. About 4 minutes in and I'm lost.

[@Nigelrathbone1]

Okay, I've heard that explanation umteen tumes before. Still no aha moment.

[@jasonmack760]

I said this to a friend some years ago. On a hypothetical world moving much faster than we are through the universe, if they were to look at us through a telescope, they would see the whole of human existence has already passed by. On a hypothetical world moving more slowly, it hasn't even begun. If you take that concept and stretch it out, you see that because of the way time works in our universe, it preserves a perfect copy of our lives. In a very real sense, each of us has always existed, and always will exist.

[@chunkyboi4526]

so someone x light years away will see us and someone 2x light years away would see our ancestors this is amazing to think about light emitted preserves our image throughout space n time

[@chunkyboi4526]

u dont even need a hypothetical world moving faster than us u just need them to be at a greater distance

[@Jp112]

@@chunkyboi4526🤯🤯🤯

[@shankarsubramaniam1779]

​@@chunkyboi4526 👌👌wow !

[@00allison00]

Wow. I love this.

[@jimmyispromo]

Chuck Nice is smarter than all of us think he is. He really understands and questions things we wouldn't. I love it

[@DABESTTTTT]

He’s annoying and ruins the videos

[@djstackademikz]

Deadass … he is keeping up with the convo meanwhile idk wtf they even talking about i keep having to rewind it lol

[@reasonerenlightened2456]

kzbin.info/www/bejne/Z3OmnIaPhpWBiLM

[@patakpatakulia7328]

Chuck's a beast

[@isaac9973]

Nah man sorry, he is just not.

[@peggywoods4327]

After seeing how much Chuck figured out and understood on his own, it's starting to look like he should be in line for an honorary degree! He has had the best teacher... it was really fun watching Chuck realize he knew what was going on and paraphrasing/explaining with glee. This was fun to watch.

[@AiNEntertainment101]

...absolutely - couldn't agree more. He's become such a well educated dude.

[@CadillacDriver]

Calm down. Intelligent people exist, don't be surprised and threatened by them.

[@larrybird9425]

Chuck always impresses me

[@TiffanySoulbird]

His "live fast die young" was perfect. 😂

[@jgage2344]

If you spend ** hours with Neil you should just get one …

[@pandaprophetable]

really cool to see chuck’s aha moments, and the depth of his questions. Thanks chuck for translating for us!

[@StarTalk]

Learning is actually really cool.

[@rrpov]

@@StarTalk yeah it is, my 6 year old daughter is learning that everyday:)

[@donsuede1194]

You know Chuck meant business with the fewer than average quips in between.

[@peterkirby1753]

Yes. I was thinking the same. Chuck loves the subject as much as us watching and does a brilliant job of translating (as you said) and saying the genuine "wows" as we are. 👍

[@mlungisimokhethi6958]

I really enjoyed this. He's genuinely intrigued, as am I.

[@Focus.D]

I feel so privileged to be able to enjoy the ramblings of our greatest minds at any time. TY Universe, Chuck, and Neil.

[@crangel2183]

Agree!

[@n-payne7684]

But thought time slows down the faster you go

[@garbuckle3000]

I remember as a teenager learning that time travel is definitely possible, but only going forward in time. It's just a one way trip. Gives new meaning to "I'll hit you into next week". It also boggles the mind that if a photon has no time, then a light-year really is extremely large.

[@geog26]

large ?

[@jacobbarjam1873]

@@geog26 you know what he meant.

[@Ban00]

Only those that don't hit a telescope are extremely large hence relativity

[@factsonly2013]

Yah well 9.5 trillion kilometers. Extremely large. Wanna know what's even larger? A 105,700 lightyears. That's the diametre of our galaxy, The Milky Way. So theoretically speaking, a photon born at one point on the edge of our galaxy would take 105,700 years to reach the opposite point, while travelling 9.5 trillion kilometres/5.9 trillion miles per year. Gives you a headache just trying to fathom the vast expanse of just our own galaxy doesn't it? We're nothing in front of it. Then there are 200 billion galaxies and that too is limited to the spectrum of what we call the observable universe.

[@alanjohn2675]

I didn't understand the correlation there between Photon not experiencing time and then light year becoming extremely large. Hypothetically a spaceship is travelling at the speed of light from our perspective we can see its travel albeit very fast but still observable for us.. but from the perspective of traveler in the spaceship he would not experience the travel itself and from Point A to Point B as soon as he starts he would reach his destination and time would not pass from him between the two points so basically for him he teleported there maybe would not have aged in his travel but for us we saw him moving from Point A to Point B that's what I understood here.

[@judahdavid8682]

Even though science wasn't my thing in college, Neil breaks this down in a way that I can understand. Mind successfully blown.

[@rhainegraves7235]

©€€° J™udah D™avid ®€€°

[@nicholas50]

On other topics, Neil DeGrass Tyson is a scientific sellout and should not be taken seriously. He has lied on several counts and pushed SCIENTISM (the abuse of science for the sake of pushing a narrative) for his own political gain in certain arenas. Buyer beware.

[@batboylives]

Thats like not being able to count and hiring someone else to do your books. How would you know if you are not being cheated out of money? You won't because you can't count. Taking something at face value is just the same.

[@MaartenSFS]

I consider myself to be smarter than the average bloke, but I am constantly impressed by Chuck’s lines of questioning AND his snappy comedical quips. His contribution is what makes the format of Star Talk so succesful. Fascinating and entertaining at once!

[@semiramisubw4864]

There is no real "dumb" person actually. There is no smart or smarter imo. Personally i think we all live in our own world and we try to express that with own views.

[@DancingAlldayLong]

​@@semiramisubw4864 LMAO

[@iownstaticz8687]

@@semiramisubw4864uhhh ok… get em son

[@Anonymous-yh4ol]

I think both Neil and Chuck together....

[@iownstaticz8687]

Oh and btw its alr been proven that people can be genetically smarter than others and you can also inherit the intelligence from say for example your dad.

[@DeclanMorton-x4b]

These two need a show. A REAL show like late night.. Absolutely insane. And this is why I love science..

[@ecadfb]

"The photon has no knowledge of that trip." I can never un-hear that. Now, I too will lay awake, staring at the ceiling... knowing the light from my neighbors porch light, the light from the moon, the light from Saturn, the light from the center of the Milky Way and the light from the edge of the known universe all reach my eye in exactly the same amount of time (relatively speaking from the photon's perspective)...

[@davidmurphy563]

Wait until you hear about Feynman's work. It's perfectly possible for subatomic particles to travel back in time. Happens all the time in fact.

[@Y_M1967]

Sounds/seems almost spiritual in nature

[@skyhawk_4526]

@@Y_M1967 From a spiritual perspective, it would seem this description of travel from the photon's perspective (timelessness) seems like the closest scientifically observable thing we can compare to the nature of God. I mean if all the photons in the universe collectively travel throughout the universe instantly (at least from their own perspective) then they are basically omnipresent which has always been one of the key attributes of God.

[@KhanSphere]

@@skyhawk_4526 omnipresence was not always attributed to god(s). Even within christianity: according to the bible, god only knew that Adam and Eve ate the fruit when he saw that they were covered. Also, humans are sentient, and god has always been attributed sentience. This, among other attributes of god shared with humans, means that we're the closest thing to gods (which makes sense, considering we made it up).

[@bigtank2185]

How did the explanation of the travel of a photon turn into commentary about spirituality and god? That makes no sense to me. People's opinions about spirituality and implying them in science boggles my mind

[@IamGroot786]

Mind blowing stuff. I recently watched "Interstellar" and so many references are made to Einstein's theories such as time dilation and gravitational effects. Great film!

[@KatyaLishch]

more mind blowing facts: Let's consider the hypothetical journey to the Alpha Centauri star system, which is located 4.3 light-years away from Earth. If time is measured in years and distances in light-years, then the unit acceleration (a) = 1 light-year/year², is close to the acceleration due to gravity and approximately equals to 9.5 m/s². Let's assume that the spacecraft accelerates with unit acceleration for half of the journey and decelerates with the same acceleration for the second half. Then the spacecraft turns around and repeats the acceleration and deceleration stages. In this scenario, the flight time in the Earth's reference frame will be approximately 12 years, while on board the ship, it will be 7.3 years according to the ship's clocks. The maximum velocity of the ship will reach 0.95 of the speed of light. In 40 years of proper time, such a spacecraft will reach the center of the Galaxy, and in 59 years of proper time, a spacecraft with unit acceleration potentially can make a journey (returning to Earth) to the Andromeda galaxy, which is 2.5 million light-years away. On Earth, during the duration of this flight, approximately 5 million years will pass. By developing twice the acceleration (which a trained person can adapt to under certain conditions and with the use of certain adaptations, such as hibernation), one can even consider an expedition to the visible edge of the Universe (approximately 14 billion light-years), which would take astronauts about 50 years. However, upon returning from such an expedition (28 billion years according to Earth's clocks), the participants risk not finding alive not only Earth and the Sun but even our Galaxy. Based on these calculations, in order for astronauts to avoid future shock upon returning to Earth, a reasonable radius of accessibility for interstellar expeditions with a return should not exceed a few tens of light-years unless, of course, fundamentally new physical principles of space-time travel are discovered. However, the discovery of numerous exoplanets gives reason to believe that planetary systems are found around a sufficiently large fraction of stars, so astronauts will have plenty to explore within this radius (for example, the planetary systems of Epsilon Eridani and Gliese 581).

[@NamemaNSl]

One point in this film interests me. It is known that when approaching a black hole, time slows down (for an external observer), but when crossing the event horizon, time stops altogether (for an external observer). The question is: how was the main character able to cross the horizon of events? After all, for any external observers this moment will happen in the infinitely distant future. That is, when it crosses the event horizon, by this time an infinitely large amount of time will have passed outside the black hole, and the universe surrounding the black hole will have long since perished.

[@KatyaLishch]

@@NamemaNSl so, you're not bothered by the fact that after crossing the event horizon he sees the freakin bookshelves in his daughter's room, but you're bothered by the lack of sufficient time dilation for an external observer?

[@IamGroot786]

@@NamemaNSl I'd say this is where the "Fiction" part of Science-fiction comes in...

[@NamemaNSl]

@@IamGroot786 In fact, this question interests me even without reference to the film. How can black holes grow if the lifetime of the universe is not enough for anything to cross the event horizon? It seems that it is believed that the event horizon still intersects in a relatively short period of time from the point of view of an external observer, but I have never seen an explanation for this.

[@Magnaheim]

I am always obsessed with space and future tech type concepts. Time Dilation has been something I could never really grasp much until this video. Explaining how the photon from 30,000 years ago doesn't experience any time itself made so much sense, it's a good comparison to show why people experience less time when traveling near that speed.

[@bjdela]

This is the first explanation of this theory that I actually now can comprehend the "relative" part. Thank you Startalk.

[@phthirius]

Stunning. I had read about this so many times, but I hadn't realized that light is, indeed, eternal. Thanks Neil and Chuck.

[@mattball420]

Doesnt look too eternal when i hit the light switch and the room goes dark lol

[@jovane486]

"Light is eternal" Blackhole/dark spots on the universe: "Are you sure about that?"

[@jofftiquez]

Same realization lol

[@chrisg9615]

Lets say I have the whole universe in a snowball and I am some giant being observing. One person in the snowball is wizzing around at the speed of light, the other is stood still. Both have watches on, then the one who was wizzing around stops. Why would their watches then be different? Because it moved? Does not make sense to me and I'm trying.

[@semiramisubw4864]

@@mattball420 We dont know if light disappears when they get soaked in actually. It could actually live on.

[@DanceBeforeTheStorm_]

OMG! Einstein was right! 😱 . . Love you guys, can't tell you enough how grateful I am for making content like this accessible and comprehensible for all ❤️ I wish I had this in school.

[@jettmthebluedragon]

Yea 😐in fact think about it what do you remember before you were born you don’t remember anything 😐you could have had a life before but you were dead for a very very long time in fact when you die you go to the same place as if you were not born 😐and eventually you will loose track of time it’s self 😳in fact we could be somewhat repeating our lives and we don’t even realize it 😳after all how would we know earth would form? How would we know it will happen ?we don’t 😐live is very strange 🤔

[@laurabenevelli6783]

It’s beyond amazing how Einstein could conceptualize this when he was alive in a time before any space travel or extreme telescopes like we have today. There was no way to prove his theory of relativity when he was alive. It took so long to be able to confirm it. How he even came up with this is incredible.

[@snehilraj6436]

The duo of Neil and Chuck is perfectly matched. I love to learn these concepts in such an easy way!

[@ericparrish1515]

How long can a can phone reach

[@Константин-ш3к]

@@ericparrish1515 Their maximum range was very limited, but hundreds of technical innovations (resulting in about 300 patents) increased their range to approximately 0.5 miles (800 m), or more under ideal conditions.

[@GmodMark]

Chuck is kinda annoying tbh

[@Cheeks63091]

@@GmodMarkHow ? is it he questions & understand things 🧐

[@alihadimajeed3372]

Imagine having a teacher like Neil for all of your school and university stages.

[@audilicous]

I would’ve probably graduated

[@porterwake3898]

I would then believe there are 500 genders.

[@alihadimajeed3372]

Why is that ? @@porterwake3898

[@MikhailFederov]

All the people who made it in life, became their own Neil to teach themselves. All the losers like you blamed not having a good teacher.

[@na3rial]

One major problem is, teachers that WOULD be like NDT can’t be like him because their class sizes are too big for individual attention as kids need, as well as overwhelmed with the amount of work and not enough resources. 😢

[@theExperiencedVirgin]

Even though I understand time dilation, it still blows my mind every time.

[@ebob4177]

Yeah it's completely counterintuitive.

[@jonathoncook8367]

Sounds like something a lot of kooks talk about in a psych ward.

[@valueofnothing2487]

It's actually impossible to understand. The faster you try to understand it, the slower your mind travels until it stops completely.

[@ebob4177]

@@valueofnothing2487 haha!

[@ebob4177]

@JFQ uhmm not really

[@JoseMTamez]

Man, for the longest time, I was asking myself what the gravitational pull of a planet has to do with time dilation and you finally answered it for me. I was watching every video on this search and not one mentioned a planet's gravitational pull. I'm telling myself, there has to be more to this story. Then bam! Out of nowhere, you began to explain that it wasn't until ten years later it was formulated that the stronger the planet's gravitational pull the slower time tics. Thanks for clearing that up for me and now I'm left wondering why this isn't mentioned more in any of the other videos. Go figure!

[@Woburn-RoxburyMedia]

This is the most fun Science Show out there! It's a wonderful show to have middle-schoolers & perhaps High Schoolers watch as part of their curriculum, to first engage them via the curiosity aspect, but keep them via the entertaining manner it's presented. Wonderful segment, wonderful duo Neil & Chuck !

[@lcflngn]

If I’d had this presentation in school, I may have had a clue, and possibly an interest, rather than staying confused entirely in the weeds, and memorizing instantly-forgotten random facts. At 60 now, I’m finally having fun learning some science!

[@jimmyispromo]

These two need a show. A REAL show like late night.

[@EOE808]

Man my brain got a workout following along. Unbelievable the knowledge built over years. Thank you so much for simplifying it for the rest of us to follow along 🙂

[@Verifyourage]

T=0 for the photon the entire distance travelled towards earth from its frame of reference earth is travelling towards the photon at light speed but hits earth at present time?

[@julieritchie1651]

Nuc med tech here. Love that I knew most of this, but you explain it so well that my mind is reconfiguring how I look at my surroundings!

[@Geaxuce]

This is actually an observable phenomenon. It's use case is understood in machining on machines like mills and lathes. The easiest place to observe it is with an analog clock that has a second hand. The outer most tip of the hand moves faster according to its relative position in relation the axle it sits on. The relative notion here is because the whole hand moves at the same time but the outer most tip has to travel a further distance over that one second. The force generated on the tip is also heavier as a result. Essential it can be used to think of gravity in relation to time. It's not that a clock will tick faster for you or slower for you the faster you move. The tip of the clock is not transcending the passage of a second relative to the axle and the gears that push it along. The moment of that second is the same. For everyone. The passage of time relative to 2 people, one driving and one walking. The one driving will get to the end of the block fast than the one walking though the arrival of 2 o clock is the same for both. Just as the direction of that second hand's tip and center pointing to 12's arrival happens in the same moment

[@thewaywardwarrior]

I love this man. His Charisma and enthusiasm is just so astoundingly entertaining and hilarious, and at the same time compelling and fascinating.

[@pro-socialsociopath769]

Still don't understand the hate he gets now. He got a little too enthusiastic during one JRE episode and couldn't stop talking, and now so many (seemingly) kids treat him like he's the devil king of all narcissists. I genuinely believe it's some psychological thing where as they grow up they want to feel "part" of something, like they're in their own little club. Their "club" that they're in is the one where they all agree to crap on NDT at every opportunity, even when he says something non-offensive and correct. It's like they're trying to divert attention from whatever he said. When you choose to dislike something you have to look at everything. Everything they have done and what it leads to. Weigh it all out, do the cons outweigh all of the pros? When we do the math with NDT, the results are still positive in my opinion...

[@nbrown6648]

This concept (photons experiencing their life history simultaneously) has fascinated me for 50 years. It makes one view the double slit experiment and in particular the delayed choice variants “in a different light” :-)

[@KnordStream49554]

I have a lot of admiration for Chuck's comprehension and quick articulation of scientific knowledge. I believe if he had the opportunity to pursue physics he could have been very good at it and probably a brilliant educator.

[@unknownspiritx]

Never had a video where I had to go back 10 seconds every 10 seconds to grasp what he’s saying and enjoyed every bit of it.

[@westcoastbred7745]

Same

[@waldevv]

This is something I had thought about so many times, that there has to be a condition where someone could see the entire life of the universe unfold within their lifetime if not seconds. I had a decent grasp of a lot of the things Neil has explained but the way Neil explains things slowly and with easy examples it just makes something click. Amazing series, so glad to have discovered it

[@Hendershot93]

This was the best episode I’ve seen from you guys ever in time!

[@KsNewSpace]

Chuck tries a bit too hard to unlearn what he learned from Neil over the last couple of years to act surprised. I think it's time for Chuck to graduate from the Tyson Academy and become an equal conversation partner!

[@William_Clinton_Muguai]

Times slows down when one: (1) Moves near the speed of light. (2) Gets towards strong gravitational field strengths.

[@CroncAstronaut]

Time slows down when you move. Doesn't have to be near speed of light. You just don't perceive it at slow speeds.

[@William_Clinton_Muguai]

@@CroncAstronaut Yeah, but time dilation is insignificantly negligible in the Newtonian world & that's why I specifically used the phrase, "near the speed of light." For all intents & purposes, time dilation is ONLY significant in the Einsteinian world & NOT in the Newtonian.

[@JJ-nh8lv]

When I was a kid, This guy had a loud stereo in his car, When he came into hearing range, the sound was distorted, but got clearer the closer he came to our position. Then as he moved away from us, his sound, again went distorted. So I said to myself, that the speed of sound, or the time it took for that sound to reach my ears, changed according to the cars speed. That was my first scientific breakthrough. Science is badass!

[@JJ-nh8lv]

@BlueBoy 1 Well, as the car comes closer, in motion, the speed sound, although constant, does change because the car speeding up and slowing down. The only way that it wouldn't, is if I were moving at the same speed as the car. Don't you just love this?

[@StaticBlaster]

I can listen to Neil all day talk about everything apropos of astronomy and astrophysics. Time Dilation really fascinates me. It boggles my mind, you could, in principle, travel far into the future from everyone else's perspective on Earth (assuming you could travel a substantial fraction of the speed of light or if you could hover above the event horizon of a black hole).

[@elenamrosso8172]

Omg, I'm binge watching this right now. I always failed and hated science, but no one explained it this way. If they did, I would probably choose the path of science. I can't put it into words how much I love Star Talk!!¡!

[@frankcryptohymer8516]

thank you Dr Neil and Mr Chuck, Im a huge fan of science and you by far are my favorite Astro Physicist! I love learning. Thank you for your contributions in science

[@jmcsquared18]

6:16 The neutron is the one decays when it's freed from an atomic nucleus. Has a half life of about 10 or so minutes before splitting into a proton, electron, and antineutrino (this is called Beta decay).

[@catherinedesrochers]

I was looking for the exact term over the internet and indeed it seemed to be the neutron with a different lifetime than the one indicated in the video. Thanks for confirming it!

I would like to see a longer explainer on this topic. I'm pretty sure Dr. Neil has even more facts in his mind. I love it!!! And also who doesn't love Chuck reactions?:D You always make me laugh and I'm not even native english speaker.

[@ystong6345]

Excuse me, that's Dr Neil and Lord Nice to you (and all of us).

Fixed, i'm so sorry. Didn't wanna disrespect doctor Neil deGrasse Tyson and Lord Chuck Nice.

[@weed42036]

Imagine that we proved that we live in an infinite cyclic universe. If we one day sent a being the speed of light, (assuming they could live through big crunches and bangs) what they would experience. they would simultaneousely go through every single possibility, every timeline, and all that could be. all possibilites at once, all within the smallest possible timeframe. *mindblow*

[@joer5057]

Or, if they could travel faster than light, they could theoretically travel back in time. Imagine a society where said person (or group) could witness what you've described but then speed up and return back with this knowledge to the instant they left.

[@ethansicard7173]

Crazy to imaging that, that is the perspective of parts of the universe. Although not living, parts of space are experiencing that acceleration, therefore skipping through our perspective of history in less time than we can imagine

[@user-wu4bo1hz3p]

They wouldn’t experience anything, because no time would pass for them.

[@thomasp506]

They would only experience anything once they decelerated back below lightspeed. While at lightspeed, they would have no experience because no time passes.

[@OrlandoAponte]

An individual might see some cool things at near lightspeed, but at lightspeed, they wouldn't be able to perceive a thing. Even at near lightspeed, things would probably happen too quickly around them to make any sense of it (like watching a movie at 10000x speed).

[@bentheuberdestroyer]

I am so late to this series but so excited to get started in it

[@tedmosby5755]

Neil blows my fing mind every time I see something by him.

[@nicholas50]

On other topics, Neil DeGrass Tyson is a scientific sellout and should not be taken seriously. He has lied on several counts and pushed SCIENTISM (the abuse of science for the sake of pushing a narrative) for his own political gain in certain arenas. Buyer beware.

[@scoobydoo3159]

How you met your lover?

[@phthirius]

No kidding. So true.

[@burner3596]

neil is a big dummy dumb dumb

[@joeexclamation5276]

Same.

[@onionrovirosa]

Chuck is amazing. He truly loves learning and I love it when he gets quiz and surprises Tyson with correct answers.

[@lukeanfossi907]

no he just says wow to everything

[@larryblack9168]

I've been a fan for years and have bought all your books. I don't know if this is the episode where you cover GPS but one of the things I love about what's necessary for accuracy is the combination of general relativity to account for the satellites being farther from earth's gravity and special relativity because they're traveling so fast, so the adjustment has to be both backward and forward.

[@connornolen3595]

Agreed. I am a civil land surveyor and I use a GPS unit almost daily. It's very cool to hear something That corresponds with the work I do and how it interacts

[@pk3]

‘Time Trap’ is an underrated movie with a nice plot based on time dilation.

[@bigtank2185]

This is an absolutely amazing explanation, and stimulates my brain for even more questions. These questions I would like to ask Mr Tyson. 1. Does the type of motion matter to dilation? For instance, does a spinning body experience dilation, the faster it spins? Or is it just lateral motion? 2. The speed of light is a constant relative to us on earth, but if I as an observer were in a stronger gravitational field, say for instance, and the presence of a black hole, would I experience the travel of light being slower? If I as the observer we're in a strong enough gravitational field, would I potentially be able to witness the travel of light? 3. On the point of photons acting almost instantaneously relative to themselves. Does that correspond with the amount of time it takes for a photon to travel relative to our observation? For instance a photon that was generated at the inception of the universe, 13.7 billion years ago. It took that photon 13.7 billion years to travel to earth. But according to that photons relative state, it experienced 13.7 billion years instantly. I'm absolutely flabbergasted.

[@antaress8128]

1. The type of motion doesn't matter. You can have merry-go-round that spins really fast. Not only time will tick slower at the edge when compared to the center but also that edge which is a circumference will be shortened. Imagine that! 2. All observers agree that the speed of light is constant. You will never see the light move slowly no matter if you are moving fast or not moving or near black hole. 3. I don't understand this question. Just want to say that from the photon point of view, the universe is flat like mfking pankake. It has no depth.

[@damascus-ut1ee]

2. When you experience the extreme time dilation of gravity near a black hole, everything will be blue-shifted including seeing the future of the universe as Neil described. Likewise, if you could travel near the speed of light, you will start seeing relativistic effects: you’ll notice colors start to change, and experience length contraction of objects in your vision. The reason for color shifts is because you’re traveling so fast, that you experience the frequency of the photon wave nature. When you are bombarded with photons, yet traveling through them at near the same speed thus frequency change (remember frequency is part of different color wavelengths) colors will change on you. The action lab’s channel has a good video on this. Or you can google “A slower speed of light” - a game by MIT labs. Also you can search videos of what happens when approaching a black hole. Some videos describe what you’re asking and others don’t. Another part of it, is that an observer watching you fall across the event horizon would never see you fall in, just stuck there as an image. Because they’d need an infinite amount of time to watch photons reflect off of you (not even light can escape a black hole) and back to their eyes. But for you, you had crossed the event horizon and unfortunately, spaghettified.

[@eureka7722]

so if you move to the speed of light you can basically teleport in no time.

[@damascus-ut1ee]

@@eureka7722 From a photons’s point of view. But the information of your traveling wouldn’t be known to humans for seconds, days, or years depending how far you’ve traveled

[@Dislob]

@@damascus-ut1ee yup. We always have to remember that everything we observe is RELATIVE to something else from our frame of reference.

[@ThatArcheryGuy]

@StarTalk by far my favorite episode, I always knew that photons didn’t experience time but I was awestruck when you put it from the perspective of the photon itself. The underlying beauty of our universe is poetic.

[@furbabydaddy814]

I’ve honestly never wondered if light aged,or not. But finding that out that it does not,is a mindblower.

[@mattball420]

Apparently it has a pretty short life span once it stops woving fast enough to freeze in time, hence turning out a light in a room and it going dark right away. A photon is literally an instant frozen in time, never succumbing to its extremely short lifespan

[@cocolove9916]

then how come the light from a star goes out or it dies and turns into a super nova?

[@aaronmiranda1312]

@@cocolove9916 that’s because the star runs out of fuel

[@cocolove9916]

@@aaronmiranda1312 is there a reason behind why ?

[@reasonerenlightened2456]

if the photon does not age then how come it stretches?

[@theboombody]

I had NO CLUE what time dilation was until I watched Neil deGrasse Tyson discuss this in one of his Great Courses episodes that was available on Netflix at one time. Boggled my mind and kept me busy for years. I'm very grateful for Dr. Tyson's work.

[@e7danny7m]

can u explain to me ... i dont get it, for me its jsut something that its faster arives faster , simple as that....

[@theboombody]

@@e7danny7m Well, to you a snail seems to move very slowly, but a horse seems to move very fast. Depending on how fast you can go, everything else either seems fast or slow to you. That's a way of saying speed is relative for most things. But light is different. Even if you move at 99.999% of light speed, light will seem no slower to you than if you are only going 1% or less of light speed. The speed of light is not relative like the speed of everything else is. The speed of light is constant to you, no matter how fast you are moving. The only possible way this can happen is if time actually slows down for anyone traveling quickly. Not just that time seems to slow down but it actually slows down. This is depicted in the 80's movie Flight of the Navigator. A kid travels around the galaxy at near light speeds, and when he meets his brother again his brother has aged about a decade but the kid himself has only aged a few days.

[@e7danny7m]

@@theboombody seems to me just a theory if we spek bout light speed. And i cant get this in my head.... For me its just things going faster from a to b point, its normal that everything else is doing it slower

[@theboombody]

@@e7danny7m Extremely difficult, or impossible to experience this theory directly. It has been tested and confirmed by scientists using extremely precise instruments we have no access to. We pretty much have to trust them because we can't test the theory ourselves.

[@사이에드예스]

The faster I write ✍️ the answers on my exam paper the slower it seems the time has ticked for me and the slower I write the exam the faster it seems the time has ticked for me. But to the invigilator it's all the same exact time period I took to write in both the cases 🤣

[@gagankumark]

I always learned something new every time I watch Neil's videos. Thank you, Neil. Love from India, Pune.

[@andrewm8429]

I look forward to the days when i get to listen to you guys

[@rolandorzabal1955]

Me too

[@jhwieder2112]

Every time I watch these episodes, I come out with more questions than answers. I teach science and love to learn what they talk about.

[@lanceallen9875]

Seems like that's how most things work with science. I hope you're a fun teacher that does experiments and makes learning fun rather then a strict teacher that just hands out home work. Seems most science teachers in my experience are pretty cool.

[@사이에드예스]

Same with my experience of time when I do pushups for 30 seconds vs when I ride a 🚗 for 30 seconds.

[@toxic_bunny689]

Honestly, having such fascinating concepts and amazing concepts of reality explained to me by great minds such as these give me amazing will to push forward. As ridiculous as it may sound, this video was able to reinforce my personal will to live. Thank you for that, Mister Tyson. I always love to be fascinated by the amazing complexity of our reality.

[@conm87]

Love these episodes! I always love to get a different spin on things I know (or learn about things i don’t). Never considered that time means nothing to a photon…

[@mohabdul1]

I had to watch this 3 times to get it. Thanks

[@Icepick7484]

These gentlemen (one well known and the other not so well known but still extremely knowledgeable) explain to us actual and truthful things that are happening (whether we understand it completely or not). Their channel is enlightenment to all us not so brilliant people who want to learn. Thank you.

[@NUCLEAR-FIRES]

Love this man! He has taught me SO much about the universe

[@coletteHawk]

This is really wonderful. Thank you for explaining the concept of time in this way.

[@impressivenewguinea4016]

Thankyou for the explanation. After two years of watching KZbin on time travel, now I understand.

[@AhirZamanSairi]

my conclusion on everything I've learned on quantum/relativity over the years: If you don't get it, that means you get it. The math points at their implications, but our minds halt at comprehending/visualizing "how."

[@kt420ish]

By the way, I tried boiling water on a paper plate (explained in a recent video, but he talks about a paper cup). You can totally boil water on a paper plate without it burning. Absolutely incredible and great experiment. Thanks Neil

[@tomsriver2838]

When I was a kid, I used to boil water in plastic bags.

[@gisli12]

We did that experiment in 5th grade

[@dj6961]

Crazy cool that you get to talk to this dude directly.. Free education 1st hand...free!

[@davidmurphy563]

Well... I'm scared to correct the great Prof. NDgT, but it's not just special relativity working here, it's also general relativity (in LEO at least) so you have to correct one way for the former and the other way for the latter. So really, Einstein was doubly right. The man nailed it. Although if Prof. NDgT was only talking about geostationary then yeah he's right, it's special relativity.

[@davidmurphy563]

I so got the capitalisation wrong... NdGT. Shame on me.

[@redmatrix]

So, relatively speaking, he was correct. ;-)

[@davidmurphy563]

@@redmatrix Ha! Can't argue with that!

[@JD-xw3tj]

I'm autistic

[@artdonovandesign]

How I love Neil and Chuck describing science!

[@Snoviz]

That was fascinating! Keep up the good work guys❤

[@AndrewS-pp2he]

I'm glad there are super geniuses that are also able to speak in a way that normies can understand. I love all the content Neil puts out. And Chuck of course makes it fun.

[@mrfilipelaureanoaguiar]

I would make some equations with those properties and attach some values that could work :T=time A=age S=size B=back in time M=matter C=constant of light CDIT=constant displacement in time CDRIT=constant displacement randomized in time LECIT=lost elements constant in time RECIT=Recuperated elements constant in time LCA=lifes constant age choice ECV=environment choosen volumetrically

[@dathyr1]

Whoooshhhh!!!!!! This all went over my head but not sure faster or slower. I am glad you explained all this that I didn't understand. I guess I need to go back in time relative to now and watch this video again while the current time moves on. As we say, it is all relative. Have a great day whatever time you are traveling at.

[@jonahda0mega]

God bless this man, his last covid video had me on point talking to my kids pediatrician 👍🏾🙌🏿

[@charlesschwab1858]

Love these videos as these extremely complicated topics are made understandable ! Thank You for Posting 🙂

[@imperify7671]

@@stellarfax ok buddy

[@andreiaperalta6441]

@@stellarfax ok😭lmaoooo

[@chaoticpainting1507]

Wow, that's just mind boggling.. I just found this channel and it's like I can't get enough.. love the knowledge that you have and thank you for sharing it with us!

[@stevepaul59]

As one professional student to another, I salute you Chuck. I just wish I could retain as much as you.

[@sj0387]

This is freaking brilliant. We need more people like Neil.

[@Dtoolman]

Neil, I love the way you can explain just about anything, that someone like me can comprehend. You rock sir... 🙂

[@less2worryabout]

Someone like you? What ever does this mean?

[@tomcat9112]

Amazing democratisation or vulgarisation of knowledge. Well done sir 🙂 thanks 1000 times.

[@WarpedYT]

So Speed and Gravity have the same effect on us as our cell phones?, the entire world unfolds around us while we are stuck in our phones...hahaha. ... we are freaking dinosaurs in the grand scheme of things tho, we truly don't know how we got here, what we are doing here or how everything actually works TBH, we are extremely primitive... but man it is entertaining and fun discovering how things work, mostly by accident!... love watching you guys!

[@misterphmpg8106]

yes we are but at least we know it (ok some people don't)😃

[@WarpedYT]

@@misterphmpg8106 lol... Great point, I guess that depends which KZbin channels you watch!. Spending your time wisely has a Time dimension of its own!

[@ssgssbeet4133]

@@WarpedYT oh stop it, we are literally still guessing things scientifically, for example, gravity, the one thing that keeps us all alive and reason why we even exist, still dont even know how it works lol, lets admit it now, we are bugs in this universe, better than bacteria, but still, bugs :)

[@WarpedYT]

@@ssgssbeet4133 that was exactly my point.

[@arashaloha6858]

I love watching Neil and Chuck. Such a great duo! Thank you for making these videos!

[@DigDeeper23]

I LOVE your videos! I wish I would have started watching them a long time ago. I guess it’s never too late to take a new path.

[@jkoorts]

A photon travels at speed of light because of something that happened milliins of years ago and still time stands still for that photon today. The action is long gone but the effect stays. That is mindblowing

[@matthewe6393]

I always think of space-time as being 'conserved'. i.e. the faster you move through space, the slower you move through time....and conversely, the slower you move through space, the faster you move through time. If you were completely motionless, you are moving through time as fast as possible. If you were moving at the cosmic speed limit (i.e. the speed of light) then your time is zero...you don't age (or experience any time!). 🤯

[@UnKnown-lp9gl]

And the slower part you mentioned is just that when we're sitting idle!😶

[@sergiodario58able]

It's all good what you said, except that at birth everyone of us has an in built time machine determining how long you will live without interfearing outside factors. Now for most of us this outside factors will shorten our lives by some degree, stopping us realizing our full potential, and it's up to us to be able to get close to it, or considerably far away from it, like for instance being run over by a car and be killed aged two. Now coming to your point, if you could live your entire life motionlessly wrapped up in a bubble, chances are you get to live your life fully, the life which was determined at your birth by your internal biological clock. No deceases, no accidents, no bullets, are there to shorten it, just your motionless body and the food and drinks you need to survive. So it may be that in this case, the slower you go the longer you live..

[@malakaihstendahl7647]

@@sergiodario58able That may be true but I believe the issue with what your saying is that technically with earth's rotation around the sun and gravity effecting us we would never truly be motionless, whereas if you were placed motionless in a vacuum that would be the true tell factor of how fast you would be fully dead

[@hareecionelson5875]

Are movement through space and time is confined to the circumference of a circle quadrant: the full distance we travel through space time is the radius (the speed of light, but as a rate of both time and space) the components of time and speed are just pythagoras: x^2 + y^2 = radius^2

[@callanc3925]

@@sergiodario58able The converse is true. The faster you move (relative to other people on earth) the longer you will live. If you were to take a space ship 3 light years away and back to earth at the speed of light, everyone on earth will have aged 6 years but you will not have aged a second.

[@RaymondStone]

I love how Neil decided to sport his closest version of an Einstein hairdo for this video.

[@quinncampbell9255]

Love watching this and knowing I knew some of this before, only to remember that I learned it from him growing up and now still learning the se things but more details

[@MrRosebeing]

"To you". "To me?". "To you". Thank made me chuckle. I hope it raises a little chuckle for my British brothers, too.

[@eyeopenvideo9038]

I have always loved these mind-blowing ideas. I don't know if anyone has mentioned this already, since it would be difficult to go through 4,871 comments, but I'm reminded of Hermann Bondi's conclusion that "the proper speed of light is infinite". This might have come from and extrapolation of the Lorentz factor where v=c, peculiar to light or other radiant energy. To my understanding then time stops, as you point out, and also distance contracts to zero. So that's effectively what they call "eternity". It's a real state of being, but it transcends time and space. If consciousness can be manifest as free radiant energy, would it or could it be the experience of eternity? Forgive me though if I'm misunderstanding Lorentz, I'm not great with math.

[@GreenDriveIndia]

In short, suppose some place is billions light years away, if we can travel with speed of light we can reach there instantly , we need to slow down may be one light year before and apply some break

[@gscurd75]

Gravity only indirectly causes time dilation. It is the effect of gravity on space. Gravity pulls space into objects and your relative movement through space is faster the closer you are to massive objects. So if you feel like you are sitting still near a black hole, you are actually moving through space incredibly fast which causes that dilation.

[@TheAubis]

Sounds good but it's just a theory,we will probably never know.

[@nitish.anand99]

Thank you Neil, I have been asking people and waiting for someone to talk about the timelessness of a photon when I understood relativity after watching Interstellar. I have been waiting since college for someone like you to address the phenomenon that I also thought was extremely fascinating. Thanks for making me feel great.

[@nenmaster5218]

„Neil Tyson is a Science-Mediator. He stopped doing Science and started explaining it. I like that. I respect that. But it gets odd or unhealthy when People pretend he’s the ‚President of Science’. Especially flat-earthers try to do that.“ -Professor Dave Explains, one of many legendary Fraud-Catchers and Anti-Science Debunkers

[@nitish.anand99]

@@nenmaster5218 I don't see a problem mate, should i stop watching his videos? Is that what you mean?

[@nenmaster5218]

@@nitish.anand99 What???? No, of course not. I want you to watch even more Neil but also start watching Professo Dave!

[@nitish.anand99]

@@nenmaster5218 okay sure, i will check him out now.

[@nuisynth]

​@@nenmaster5218 the educated can easily see that Neil is simply good at explaining complex science in layman's terms. This doesn't mean he can't explain it in scientific terms. This isn't a problem, so I'm a bit confused by the intent of your reply 🤷‍♂️

[@Styl.vation]

Keeping in mind all the endless possibilities/phenomena in our universe, I wonder if there’s something even faster than the speed of light? How fascinating!

[@braydenjameson710]

I was literally just trying to explain this to my friend, and now this video comes out. what a coincidence

[@pest174]

It's a coincidence that a bot copied your comment.

[@ericparrish1515]

Get YOU a job doing something

[@trajcepiperkoski7492]

There is no time,there is no past no future only Endless now .

[@TheMadcowwww]

Just stopping by to say this is incorrect scientifically. And on the contrary, science as we know it, proves that the past and future are just as real as the present but the exist in a 4th(or 5th maybe) spacial dimension.

[@ganymede3141]

The frightening implication of this is that if some civilization in the Universe can figure out a way to travel even at 99 9999999% of the speed of light, they would be able to travel between not just solar systems, but across galaxies and between galaxies effortlessly in just a few hours or days in their reference frame. This also implies that light can travel from one edge of the Universe to the other instantaneously. Which also implies that the cosmic background radiation could just be the same light bouncing eternally back and forth between the 'walls' of the Universe.

[@LEETLOOT]

Time still ticks for us though. The likelihood of that civilisation showing up during the era of humans doesn't increase. Regardless, the idea of traveling forward through time is still pretty cool even if we can't go backwards.

[@ganymede3141]

@@LEETLOOT Correct, time still ticks for us, and our window of civilization has been small, but if some aliens set out for our solar system 100,000 years ago because they spotted a planet in the habitable zone, they might show up at any time and be surprised to find humans here. The probability of that is of course very small, but it's still there. My point was that we are not as protected by distance and the time it takes to get to Earth as we thought.

[@TheAubis]

@@ganymede3141 how do you know the probability of that very small.

[@ganymede3141]

@@TheAubis I DON'T know. That's why I said "IF some civilization in the Universe...." I prefaced it with an 'if'. And you don't know what the probability of such a civilization existing is. Nobody does. The best we have are vague guesses using the Drake equation.

[@thandanimlambo4548]

"Live fast die hard" I can never unhear that

[@gilliangailliaert3347]

Best. Episode. Ever. Love you Neil, you’re truly an inspiration and my biggest real-world hero.

[@ericparrish1515]

Yes they are

[@TheJtyork420]

This is such a great topic. For the past month I've been wondering if u could be in a stable orbit around a black hole how long would u live? Or would u even notice a difference or because it's relative would ur life progress normally with no noticeable difference?

[@BibboSama]

@Vishal its literally the plot lmaoo

[@emalee8366]

Now you have me wondering if time dilation is related to Fermi's paradox. Haha. Probably not, but who knows.

[@TheJtyork420]

Lol oh God that is the plot of interstellar isn't it. I completely forgot about that movie.

[@BibboSama]

@@TheJtyork420 yeah it be like that lol

[@davidmurphy563]

Ok, this - like most of physics - goes back to Galileo. Who are you moving _relative to?_ You are in a frame of reference. If you're orbiting a black hole then (tidal forces spaghettifying you aside) from your frame of reference, nothing changes. You live your life, all is good. But your frame's time compared to the frame of someone in deep space is very different. How much depends how close you're orbiting to the black hole and how massive it is. To answer your question, you would observe no difference whatsoever apart from seeing the universe around you changing very quickly. Perhaps you could see stars be born and die while you make a cup of tea.

[@RichieB40444]

Time is so elastic. It's almost impossible to comprehend the totality of the beginning and the end. From an outside prospective, time/space could be a pulsing entity that contracts and expands according to the observers speed/mass.

[@breannaflores4175]

So I just rewatched one of my moves as a kid Over the Hedge- animated movie about animals breaking into people’s houses to get food for the winter and also pay back an angry bear- but there’s a scene where a very hyper squirrel drinks an energy drink and gets so hyper/ energized and moves so fast the earth stops moving for him. I’m sitting there watching that scene specifically and I think “THIS IS WHAT NEIL DEGRASSE TYSON WAS EXPLAINING NOW IT MAKES SENSE” When I first watched this video of him explaining time dilation I was trying to picture it and couldn’t wrap my head around it, but then I rewatch a kids movie and a random scene depicts it perfectly

[@breannaflores4175]

kzbin.info/www/bejne/lYnLZWCZZ62ci80si=S0A3Q9Zam4EdqNuA The clip of the squirrel