Why Time and Space swap in a Black Hole

[@ScienceClicEN]

Hope you like this new video! About this video, it was a work of research, trying to find the most intuitive depiction of why time and space swap around inside a black hole. I wanted to find a set of coordinates, or a diagram, that would be mathematically accurate from the scientific standpoint, as well as being easily explainable in layman terms. For this, I have developed a more intuitive (in my opinion) version of Penrose diagrams, which, for those interested, consists in embedding the Penrose diagrams in the complex plane, and applying the conformal transformation z→z². This allowed me to generate a curved grid (used throughout the video, at 6:08 for instance), which is more intuitive than a Penrose diagram in the sense that "motionless" objects still move in straight horizontal lines, while clearly displaying the orientation of "time" and "space" (from Kruskal coordinates), and thus keeping lightcones oriented at 45° everywhere (thanks to the conformal transformation). Btw let me know if you have seen such a diagram before, I personally haven't, which surprises me since the construction is not so difficult to come up with. As a little bonus here is a preliminary simulation I had done while preparing for the video: kzbin.info/www/bejne/gmG4mp-OjJhnmdU About something else, if there are Spanish speaking people among you, don't hesitate to check out the new channel in Spanish. We will soon translate the main videos of this channel in Spanish. We just started it a few months ago, and it would help a lot if you share with your Spanish speaking friends or family 🙏 kzbin.info

[@whatsup3519]

I have a question when a ball fall from top, we can't reverse it . Which is similar to dropping ink to water which we can't able to reverse due to increased entropy. But when ball is falling down where can we see "disorder"? Could you please make a video about it or answer my question

[@heikotessmann1964]

Yes! I do. Or in German: Ja, tu ich. Danke. Thanks.

[@jayorag]

Gracias!

[@ProgressiveEconomicsSupporter]

Shiwn the topic in a very nice way, though I cant really see the switch to tine behaving as space and vice versa. Another German video tells, that movement through space now only allows one direction to the center (instead of 3 freedom grades outside) but time might be more freely moved through now 🤔 However I dont see any ohysical reason why a black hole should be an empty sphere, but massive. How do we know if our physics still work right below the horizon, and does not only break in the very center (unlikely beeing of infininte density)?

[@JubilantJerry]

@@ProgressiveEconomicsSupporter So there is no sudden transition, space and time are continuous and curve smoothly. A falling observer doesn't experience anything weird: if they are inside a small box with no windows (and assuming the black hole is much bigger than this box) they have no idea that the box is falling at all. So they can still move in 3 directions inside the event horizon. There actually is no single direction of time or space, there are multiple coordinate systems that are all valid. Like you can say the +x direction is your left and I can say the +x direction is your right, and both can be correct depending on how we draw the axes. A direction for time describes the world line of some observer. You can say the time direction follows your world line and therefore you move purely in the time direction, while someone in a fast spaceship can say that the time direction follows their spaceship and you are therefore moving backward and not purely in the time direction, both are correct depending on how the axes are drawn. Outside the event horizon, the direction that results in hovering at a fixed distance is a valid direction for time because observers can move in such a way. Inside the event horizon it's impossible to hover so no valid time direction points perpendicular to the radius. But it is in fact possible for observers to move directly in the radial direction so that becomes a valid direction for time. If chosen so, the other 3 directions: east-west, north-south, and past-future, would be the corresponding directions for space. So the event horizon marks a boundary where the intuitive coordinate system stops working and the weird one with time and space swapped starts working. But it's also just as possible to gradually change coordinate directions while getting closer, resulting in no sudden change at the horizon. Such are how the coordinates the video used work (if you're curious, the video uses Eddington-Finkelstein and later Kruskal / Penrose. The coordinates that have a sudden change at the event horizon is called Schwarzchild coordinates).

[@mrdre3628]

People underestimate how important good visualization graphics are to a complicated subject; I've understood the concepts of what you're saying for a while theoretically, but seeing it laid out so clearly definitely clarified things and I understand Penrose diagrams better as well so thank you...hopefully science educators can unlock the secrets of clear and understandable graphic design

[@f1reflam3]

Good visualization is not just important, it is often the key to understanding something. Visualization can in most cases make the difference between understanding a concept and not

[@mrdre3628]

@@f1reflam3 I agree completely

[@rupertchappelle1089]

All gravity well graphics are wrong. The bottom of the well in in the center of the mass, not under it. See corrected gravity well model.

[@Bassotronics]

If this was all taught to me only in math form, I’d understand absolutely nothing. But an A.I. would understand everything!

[@JugsKise]

@@rupertchappelle1089 Well, if the corrected gravity well model is correct, that would mean *most* gravity well graphics are wrong, not all 😉

[@MrHopecoreOfficial]

"The horizon of the black hole is no longer a place in space, but a moment in our past. And the centre of the black hole is no longer a point, but an event in our future... a destiny we cannot avoid" Something about this gives me chills

[@naysay02]

Yes! Beautifully captured the irresistible dark power of a black hole

[@Dominus_Augustus]

Truly terrifying, but also fascinating to say the least

[@electriceyeball]

This must be how the Bene Gesserit in Dune feel

[@ashgonza92]

@@electriceyeball L

[@Victor-ti4fx]

Doesn't that mean we are currently falling towards a singularity?

[@ARIY1411]

This is the best video I have ever watched. The moment when you described how Space Time works visually was like an epiphany for me. Thank you for spending the time to create a video with such clear explanations. I hope you are able to continue making high quality videos.

[@NoDarks]

Stupid consumer, why would you ever give someone on KZbin money.

[@labplay6771]

I like how you take pauses for us to grasp and figure everything out

[@MrShtrudL]

Couldn't agree more

[@FartGirlForever]

EXACTLY

[@counterleo]

I still hit pause and uttered a loud *bruh* when he said the event horizon was no longer a place but an event in our past

[@dharmatejamyneni4879]

KZbin ads : we have more pauses

[@jacobshirley3457]

And having great visuals and background music also helps fill it out.

[@igbaccin]

"If the apple falls, although it was motionless at first, it is because its future points downwards". This! This encapsulates the role gravity plays on time wonderfully. It felt like everything I read and watched on the subject suddenly clicked. The "aha!" moment! I deeply thank you for the insight.

[@giacomofilippin12]

Even if I already understood how and why that happens, this added a beautiful interpretation to it, really really perfect explanation

[@davem1658]

When in the video does he say about the apple had its "future point downwards"?? This wouldn't work on normal earth gravity (except black hole) as its future is not certain from the point of motionless in the air. It could be hit back upwards with something.... (your comment sounds like the apple's future was certain) I would state that the structure of space near a massive object distorts, constantly.... Continually going straight line to curve towards the center of the earth. Its this that starts the apple falling down. Time is the process of it falling. I don't think your idea of time in your comment is accurate.

[@igbaccin]

@@davem1658 But then do you think the idea of time presented in the video is at all accurate? I am directly quoting it starting at 5:50.

[@davem1658]

@@igbaccin Oh ok, you've directly quoted it. I've missed that.... I really have no idea, and I defer to your assessment. ... What I like to know is; the very exact moment the apple is motionless in space, what starts its trajectory on the curvature of space of falling down? What gives its initial push from 0 acceleration?

[@igbaccin]

@@davem1658 don't quote me on that since I am not at all an expert but I think the apple does not require any push because it is already has a trajectory through time. The apple, and everything else for that matter, is continually moving through time. It would only remain "floating" if it was in a region where spacetime is not distorted. I think this is the mind bending thing! You do not need to be pushed towards the earth if you are motionless within a region of spacetime that is distorted by earth's gravity. By virtue of moving through time (and of course always forward in time) your trajectory through time will meet the earth's trajectory through time. I think this is the rationale behind the quote at 5:50. You can even see the author displaying "stacking earths" at the bottom of the screen during this particular explanation to denote earth's movement through time (already illustrated at 0:54). I may be getting this all wrong, but this is what I understood from the video and from whatever else I consumed on the topic!

[@martyd8175]

I'm a 50 year Old Irish man and has actually made me feel intelligent. What a fantastic way to illustrate the concept. The light cones have made everything fall into place. It's taken me 50 years to find something that allows me to grasp it!!!!

[@Greenfist007]

That's cause your a do'er not a dreamer . They have absolutely no idea what's going on it no doubt it will all change around in a few years time and then again a few after that. The only way to change the future is to do something . To act, not just sit there with your tongue hanging out the side your mouth drawing lines in the air.

[@yngtylrdrdn]

​@@Greenfist007what tf are you talking about?

[@Greenfist007]

I dont' know@@yngtylrdrdn

[@toastycrystaleclxpse3423]

@@yngtylrdrdn you see you are a dreamer not a do'er. They have absolutely no idea what's going on it no doubt it will all change around in a few years time and then again a few after that. The only way to change destiny is to absorb it yourself, then to combat it. To do, not just sit there with your tongue hanging out in space time tracing curves. That, is how one attains destiny.

[@streetwiseyoungbull872]

@@toastycrystaleclxpse3423consider yourself a smart man do you

[@rikschaaf]

It's quite enlightening to see what is meant with time and space flipping when NOT looking at a penrose diagram. The 45 degree angle of time at the event horizon really makes it easier to understand.

[@ScienceClicEN]

I'm glad you liked it! I also think it's easier to understand this way, Penrose diagrams are great but not really intuitive

[@renaldohill5116]

Agreed. I’ve never really understood what was meant by “they flip” this was a definite “ah ha” moment for me. So many other channels, such as Sixty Symbols are wonderful, but too often the scientists on there are like, you can’t explain these abstract concepts to a layman. Science Clic is like, hold my beer bruv and I love it.

[@-_Nuke_-]

Roger Penrose is a genius!

[@seraphik]

yeah, visualized this way it was so obvious and simple that i feel like a two year old would get it. yet up until now I've really really struggled with this concept! bravo science clic. truly the best relativity/cosmology channel.

[@owlredshift]

Einstein is a genius!

[@studypurposeonly69]

This just blew my mind honestly! Since we can't access past events and the fact that space and time switch each other at the black hole, the outside of the black hole actually becomes an event in the past from a point in space! This is another elegant way of saying "Nothing can escape a black hole". Mind-boggling video as always

[@JoseAndCode]

In the incredible chance that we were to learn how to move backward in time, I wonder if this means we will be able to escape a black hole

[@studypurposeonly69]

@@JoseAndCode I am pretty sure at the time we discover how to travel back in time, we will simultaneously be able to discover of a way of escaping block hole

[@anubhavpal5782]

@@studypurposeonly69 true

[@anubhavpal5782]

@@JoseAndCode or maybe forward in time ? Since time slows down and is supposed to stop at the centre of the black hole. Meaning if we calculate correctly, we can enter black hole or stay close to the event horizon at one point in time and escape it at another point in the future ?

[@halfjack2758]

@@JoseAndCode by this analogy, since the light cone is turned towards the black hole, you could move backwards in time within the event horizon

[@steamyninja8881]

I’ve watched countless hours of science videos, but this video finally unlocked the meaning of space time for me. The explanation using light cones finally did it for me. I’ve got a clear understanding of it now. It felt like unlocking a dormant memory in my mind. Refreshing. Thanks

[@kato_dsrdr]

The science community really need to give awards to people who teach us, ordinary people about science.. It's honestly a HUGE contribution for humanity..

[@youngboy2pacdrake]

it can come, there is a disease from a black hole named HM-248, it causes liver failure

[@Emc4421]

Pay good teachers more!!

[@Thumper770]

a real teacher will teach regardless of compensation. @@Emc4421

[@Anolaana]

In the EU there is the Science Communication Prize.

[@ChinCo1]

Nice.@@Anolaana

[@marcelo.pastorelli]

This is arguably the best science channel out there. Thank you for your efforts in sharing knowledge!

[@jaredf6205]

Absolutely, more concepts have clicked for me from watching this channel than any other of the great physics channels.

[@DragonKingGaav]

Most definitely!!! ScienceClic is In a Nutshell on steroids!!!

[@ScienceClicEN]

Thank you very much it means a lot 🙏 I hope you'll enjoy the next videos!

[@folepi7995]

i dont agree. there are too many good channels on this topic. Its a fantastic channel to visualize the concempts and get new insights. But its not that simple as some videos of this channel might suggest. general relativity is so weird that you can interpret it in a thousand ways and alot seem right and wrong at the same time. to really understand more, you inevitably have to lean the calculations. There are some beatiful lectures on that on youtube.

[@marcelo.pastorelli]

@@ScienceClicEN definitely will. Thank YOU

[@C_Corpze]

I love how this is done, little pauses to allow us to catch up, simple explanation and good visuals that help picture it better. Thank you very much!

[@HodsBroo]

I've watched hundreds of hours of content and videos regarding 4D Space Time and I'm once again reminded at how the representations in your content are of the very best possible. You have a way of making things so simple and elegant, that they become easy to relate to and digest. Very good work.

[@ScienceClicEN]

Thank you very much 🙏

[@eneafrancesco]

Holy Moly! This channel has created by far the pedagogically highest quality way of teaching extremely complex subjects. Thank you so much for the great work that goes into these videos: they inspire me again and again in my interest in the universe, its rules, and in my efforts to inspire other people too!

[@-_Nuke_-]

Yes this is by far lightyears away from channels like PBS spacetime where they confuse people instead of clarifying things to them!

[@OregamiStars]

@@-_Nuke_- AGREED, PBS SpaceTime videos can be easy to get lost very quickly sometimes but this ?? my god-- this should be taught in all schools around the world, imo

[@AverageAlien]

@@-_Nuke_- PBS doesn't confuse people, it just doesn't have nice visuals

[@-_Nuke_-]

​@@AverageAlien yeah visuals can really help grasp a concept as hard as these!

[@dbooze148]

Perfectly put!

[@shanegts2662]

Spent so much hours watching black hole and spacetime vids believe me when say this one deserves an award.

[@timothynoll4886]

1) This BLEW MY MIND because it gave me a whole new and much better perspective on how general relativity, space, time, gravity, and black holes work. 2) Thank you for the pauses between sentences because I would have been lost as heck otherwise.

[@youngboy2pacdrake]

it can come, there is a disease from a black hole named HM-248, it causes liver failure

[@ayushvyas4510]

I never truly understood the meaning of light cones concept... mentioned many times in other videos but never elaborated so beautifully....as soon as you turned that 2d to 3d...clarity was there ... Thanks a lot bro, you are a gift to this world 👍👍👍

[@ScienceClicEN]

Thank you very much! Very glad you liked the visuals, it was a tough challenge to represent light cones in a video!

[@ayushvyas4510]

@@ScienceClicEN seriously...I watched PBS which is good at visuals....but everyone representa the cones directly on space time grid and then reveal the Penrose diagram immediately....it doesn't give viewer the time to get the concept and visualise that its a 2d representation of a 3d sphere expanding....now it feels really really easy...

[@ayushvyas4510]

@@ScienceClicEN visuals were as clean as one could make them... amazing mind you have got👏👏

[@zazugee]

imagine you're walking in a dark place while holding a light torch and walking forward, you can't walk outside the lightcone of your torch

[@Blackhole_T618]

This has got to be the most interesting and terrifying video I’ve ever seen “The center of the black hole is your future” is an amazing phrase lol

[@goga7301]

Your videos are criminally underrated. Such a masterpiece!

[@ScienceClicEN]

Thank you very much 🙏

[@horizonvariations]

Fascinating to hear that it is not a black hole's huge amount of force that drags us to its centre, but a future event in time instead. Brilliant stuff!

[@MrCmon113]

Yeah under general relativity, gravity isn't a force at all and that distinction is actually important for the definition of an inertial frame.

[@mariusg8824]

Just to rephrase what the video already said: the reason why objects fall to earth, is because more future paths point towards earth than away from it. So an object with random movement will always fall towards the center.

[@NoDarks]

Gravity is a force, and very observable, thanks redditor.@@MrCmon113

[@NoDarks]

"huge force that drags us to center" it's because gravity pulls on time and space. Like obviously you're going to crash into something if it has gravity, this video is trying to make it way more "big brained" than it is.

[@NoDarks]

And if it were the case that it's because "oh time is just pointing there dur hur" that breaks the whole speed of causality thing. I feel like science is just being made up at this point.

[@sgringo]

I've watched this video several times over the past two years. Each time, I'm amazed anew at how brilliantly this nonintuitive concept is explained. This is, by far, the clearest description of time's relationship to general relativity that I have seen.

[@ltsecondincomand]

This has got to be the best explanation of how light cones and gravity are related I've ever seen. Its so good it made me retroactively understand videos I've watch before.

[@badmashlarka6146]

This is probably the best video I have ever watched on internet on this topic.

[@aaqilkhan]

This guy deserves his own TV show on Discovery Channel. Amazing the way he explains complex physics with intuitive and easy to understand animations. Great work!!!

[@pranayranjan3777]

This guy never fails to amaze us with his wonderful animations and easy to comprehend explanations... I Salute your efforts

[@kryptobash9728]

Def the best video on KZbin on understanding light, black holes, and just the fundamentals without getting confused. Very well done!!

[@LAK_770]

There are SO many videos about these topics, some from eminent physicists in prestigious lectures, but they basically cover the same material and I’ve seen nearly all of them. But this video performed the rare feat of actually presenting something “new”. Never had I seen this topic presented with such distilled focus and clarity. Incredible video.

[@FunkyDexter]

Already 2 minutes in and you answered something i always asked myself, why light is placed at 45° in Penrose diagrams. This kind of intuition is rarely taught even in university.

[@thedeemon]

This video says it's 45 degrees because light speed is constant but that's not really the answer, any constant speed draws a cone of some fixed angle. It's only 45 degrees because we choose the scale of spatial and time axes such that light goes at 45 degrees.

[@ScienceClicEN]

It's rather that light travels the same distance through space as it does through time, using natural units. In 1 year of time, it travels 1 light-year of distance. It can be considered an arbitrary choice of units, but it's not so arbitrary, it's the only choice of units that is "natural", in the sense that nature specifically gives us something invariant such that we can measure time and space with a same unit : light

[@LuigiSimoncini]

@@ScienceClicEN I recently discovered that the fact that " light travels the same distance through space as it does through time" is just a convention kzbin.info/www/bejne/poXRZ3itncdlbc0

[@高若嵩-t6r]

@@thedeemon Well, in order to do angles, you need to take arctan (y/x). But this only works if y/x is unitless, and if your y axis is in meters while your x axis in is seconds, well... it doesn't work. Instead, we label the x axis as "ct": the distance light travels. And because the distance light travels is equal to the distance light travels... arctan(y/x)=arctan(1)=45 degrees.

[@thedeemon]

@@高若嵩-t6r Nope, this way you'd get 45 degrees only if c=1. This is the natural units the author mentioned.

[@AkshatMehra-l4b]

The visualisation and graphics on this channel are unparalleled. Simply what I needed to see, this guy does it and excels at it !

[@josephbanaszak9662]

You just accomplished in 12 minutes what 12 years of schooling never could for me. Thank you for the amazing videos!!

[@salvatoreventre8193]

This guy should win a Nobel Prize for teaching Physics.

[@vesa.koskelainen]

Thanks for the pauses between sentences! I really needed those breaks, to understand what I just saw and heard

[@booJay]

I'm going to say it: Best channel for explaining/visualizing physics concepts on KZbin, and that's saying a lot considering I'm basically subscribed to them all. You really are doing a tremendous service. Please keep it up!

[@bettercalldelta]

Beautiful explanation, I finally feel like I understood something about general relativity and black holes

[@AverageAlien]

Keep putting Ukraine flags in your name, makes spotting idiots much easier

[@kyleflanagan8410]

Zelensky had the deaths head emblem on the other day, they got all our baby formula too

[@bettercalldelta]

​@@kyleflanagan8410 why do you comment this on non-political videos, kremlin bot?

[@YASH-iz6tm]

The absolute best video to understand General Relativity. Although, I'm a physics undergrad and doesn't have it in my courseworlk but this channel has made me visualise the most counterintutive concepts. Kudos to your work!!

[@CerealMJ]

It's extremely hard to find science channels that doesn't have stock footage as they explain certain concepts, but you nailed every single animation, narration, and explanation. Perfectly well done :)

[@gianpa]

Mind blowing explaination as always.

[@ScienceClicEN]

🙏

[@chronoflareandedare4834]

Dude D: Where was this my whole life, I've been trying to find someone who can explain how this works and many have tried, but this is the first time EVER that I actually understand it... Thank you so much, you made me smile today :)

[@Larsalexxanderson]

Oh my goodness is what I kept repeating in wonder and amazement while watching this video, this is beyond simple scientific knowledge, this is an unbelievable new level. You’re truly a pedagogical and didactical genius to transmit things with this level of clarity, underrated channel that will explode

[@-_Nuke_-]

yep 100%

[@aniksamiurrahman6365]

The greatest revelation I got is that the singularity isn't a place. It's an event, much like getting old or becoming father. So, one will not see the singularity as a point ahead of them, just as one doesn't see their older self sitting ahead of them. Rather, once past the event horizon, it will feel like the whole world is weirdly twisting, stretching and collapsing from all side, until everything is collapsed to (by GR*) a single point of nothingness. * GR = General Relativity.

[@praveenawesome2182]

Yeah

[@DoofEvil]

this is gonna take a few days and a few watchthroughs to fully understand and easily visualize, but wow what an amazing video. such a complicated topic explained so beautifully! i always love getting new ways to visualize and understand spacetime

[@anonymousanonymous7304]

Best explanation ever for this! Thank YOU! I knew space was curved, but didn't understand why. I heard from a friend that "time is folded", but I hadn't made it that far yet. This is much clearer. Didn't expect cones.

[@vasilyp]

I cannot believe even after all this time of knowing how extremely talented you are in communicating knowledge in such a unique way and after having watched all of your videos, that you can STILL amaze me and blow my mind off with perspectives I never had thought and most probably would never think of on my own! You are truly a prodigy! THANK YOU, THANK YOU, THANK YOU

[@DoctorRocker66]

This is the best description of a black hole I have ever seen. He gives a whole new way to comprehend why you can never escape a black hole. Well done sir, you just got yourself a new subscriber.

[@UncleFester84]

This is both incredibly fascinating, mindboggling complicated, and immesurably frightening "the centre is no longer a point in space, but a future inevitable".

[@luxsings6871]

This was really well done, you can see the time and effort you've put into animating and explaining a concept that was much harder to understand before. Specially how you kept bringing us back from a compressed viewpoint back to a 3D world. Thank you!

[@palanikumarasamy3677]

9:44 the horizon of black hole is no longer a place. But a moment in our past and center of black hole is no longer a point, but a event in our future 10:36 it is a light cone...rendered motionless by curvature of spacetime Ahhh....moments of this video to me. Thank you for your wonderful animations I never learned relativity with this clarity!!!

[@ScienceClicEN]

Very glad you liked it! 🙏

[@NaomisCreativeArts]

I actually love this guys videos, the clarity, the accent, the animations, the graphics and the fact I learn more from just one of his videos that from all the years of classes with my science teacher.

[@jimwang3084]

I am a freshman student who wish to major in Physics specialist at the University of Toronto. Your videos are very awesome, they make very complicated stuff such as general relativity and quantum mechanics become very simple to understand. Hope there will be more wonderful videos released in the future.

[@majorrgeek]

Jim Wang - when you get to learn some more physics you'll start to realize this video is a pile of crap

[@youngboy2pacdrake]

it can come, there is a disease from a black hole named HM-248, it causes liver failure

[@rafaelvillalobos9145]

Awesome video! I've watched so many videos about black holes and timespace and gravity, but they never ever mentioned the concepts that this man discussed and I never really understood why light could not escape a black hole's gravitational effect.

[@Mnerd7368]

Did he just explanED how to "time travel" through the curvature of the fabric of spacetime continuum!? Beautiful explanation with visual graphics. This is the type of video i was looking for.

[@dinoflame9696]

Another banger. I discovered this channel after your visualization of relativity, and there are many good theoretical physics channels -- but you do it perfect in terms of pacing, level, description, comparisons etc.

[@-_Nuke_-]

I think this was one of his very best so far, mind = blown!

[@VinnyUnion]

i'm just saying this once, i've watched a lot of things regarding this topic and ... this was by far, the most comprehensive explanation i've ever seen. not necessarily because i don't know but because i like to hear something new if possible and different ways of approaching such a topic. many channels have like those mathematical formulas and whatnot to sound extra smart.

[@testsalvador5695]

This needs more view. Simple, no drama, direct to the point with extremely clear visualization that suited general audience.

[@vigneshdesmond]

One of the greatest science channels I've ever seen, it really reinvigorated my interest in astrophysics. Also I absolutely adore the clean visuals and animations, the fantastic narration from Octave Masson, and the beautiful ambient background music - "Musique Mystérieuse". Thanks Alessandro Roussel, for your magnificent work!

[@quickmana]

I keep learning this and feeling like I have a grasp on it, then discovering I was missing something critical and learning more! Thanks for the breakthroughs and looking forward to the next one!

[@cinemaipswich4636]

After years o trying to understand "Space/Time/Gravity", this is the first proper visual explanation that I have seen. Every student of Physics should see this video. It is clear and concise, and lays out these 3 things that are everywhere in the Universe.

[@stevenschilizzi4104]

An absolutely excellent presentation, brimming with clarity (in spite of black holes!). ScienceClic remains as brilliant as ever. Thank you!

[@caruzo9631]

how this channel doesn’t have MILLIONS of subscribers is just way beyond me 🥶

[@ScienceClicEN]

🙏

[@literallybiras]

Many science channels have been doing for a long time so I guess with patience he will be up there also, his content is very good

[@caruzo9631]

@@ScienceClicEN Hello Mr ScienceClic, I was wondering if it would be worth making a video related to your GR and Gravity Videos about “how spacetime curvature behaves INSIDE planets”. Is there still a gradient inside when you have mass in all directions? I’m not educated enough to understand it but i can’t help but feel there must be some interesting things going on in there. LOVE your videos please never stop blessing us!

[@praveenawesome2182]

@@literallybiras True

[@randomkommentelo9015]

Because people don't care about stuff like this.

[@johnbhai7147]

The animation was so good and understandable that for those who were not a physicist may enjoy greatly.

[@broken_radar]

Thank you so much for this video! This is the clearest and must intuitive explanation of the time/space relationship in highly curved regions of space-time I have ever seen. Amazing work!

[@Name-js5uq]

Oh my goodness I am so happy you didn't change the music that is why I love listening to the show so much that music is awesome in the background and your videos just wouldn't be the same without them so thank you for choosing the same music I love it so much!

[@larrywalsh9939]

2:35 - "Causality, the fact that one event can trigger another, is limited by the speed of light" - you've got that backwards. The speed of light is limited and defined by the speed of causality.

[@duncan_danger]

That supernova animation was stunning. When you say that time and space "flip", I thought perhaps that beyond the horizon you can traverse time freely, in the way that we currently traverse space freely (or at least when propelled by a force). But that final diagram makes it look like instead the light cone of causality just has an end boundary and you cannot traverse neither space nor time.

[@xeryan]

Like a freeze point, the center of the black hole, where you cannot move, time included, everything there is 'frozen'

[@gyro5d]

@@xeryan It's Absolute Zero mediated to center. The Inertial plane of infinite capacitance.

[@nmarbletoe8210]

inside the horizon, i think you can go left and right but if you try to go outwards you fall faster inwards

[@gmrecneps]

Thank you so much for putting this and all of your other videos together. Each is a truly monumental achievement. A global treasure. A timeless artifact of the achievements of our species. Please keep making more. You are changing the world.

[@jojnokirk8035]

this is without a doubt the greatest explanation of black holes, spacetime, and general relativity i've ever had the pleasure of watching

[@loppol711]

Amazing videos as usual. High quality graphical depictions plus clear explanations makes this complex subject relatively easier to understand.

[@alankarhaikerwal9826]

This is pure science, the way you teach is incredibly incredible.

[@sMcRea1]

Thank you!.. I'm not a physicist but am fascinated by physics :-) I'm listening to the audio book From Eternity to Here by Sean Carroll. I was struggling with the concept of light cones which are fundamental. Now I can go back a couple of chapters and re-listen, thanks to your video :-)

[@NandishA]

This is by far the best explanation of space and time I have ever seen. Great work!

[@OneEyedAnaconda]

My man I am in awe of the approach you take to teach this. I've studied lightcones rather rigorously in my life and i thought to have understood the meaning of the sign flip in the causality equation as the observer crosses the event horizon. The switch of the roles of space and time as one crosses the event horizon seemed like a bit of a puzzle to understand always. But your explanation drove the point home in truly the highest regard possible. Sure with the many speculative theories around describing the nature of a blackhole, it can be a rather messy venture to try to describe the "truest" description of what will happen. But your explanation essentially captures all the theories we already regard as true and factual and paints a rather astonishing picture of what we thought we already knew. Again great job man. I have a question of the community though. We drew a lightcone for 2D space. A lightcone basically being a 3D object in which the 3rd dimension is essentially 'time'. So in reality is this 'lightcone' rather a 'hyperlightcone' drawn in a 4D structure? And is there an intuitive way to visualise it?

[@theaussiewaffle4276]

the way i think about it, wherever you were born is where your light-sphere begins. Since we can never travel the speed of light, we will never come close to the surface of the light-sphere. Hence, the light-sphere that began since you were born / the initial frame of the observer is the only one you can have - and encloses all future spheres. Kind of like how our universe has an observable limit - just in reverse. As for time, I visualise it as simply a growing sphere from that origin point - in reference to whatever structure I'd like.

[@Axagoras]

This information is both awesome and terrifying all at once! You do a phenomenal job of explaining nearly incomprehensible concepts.

[@batbawls]

This series of videos are absolutely amazing. Fantastically brilliant.

[@kelast203]

3:20 also has the potential to be an excellent depiction of time dilation. If we assume each frame of that image were one hour apart, and one object were to move at relativistic speeds, the frames of the object would become increasingly spread out as it approached lightspeed; the other object would thus have relatively more dense time frames, and experience more hours within the same global time.

[@Doones51]

Thanks for speaking slowly and pausing to let us grasp what you have said. So many science videos seem to be created by "speed freaks" who can't seem to talk fast enough, and it makes it much harder to understand the subject. You do a great job of explaining and diagraming. Thanks for your efforts.

[@curiouslyt2123]

Wow! Explained very very well and plainly enough for most to grasp!

[@drphwoar]

The power of actually pausing after a sentence.

[@davidkelley5382]

I have watched so many shows & vids on space, astrophysics & black holes. I have never heard it explained so concisely. Very well done, subscribe…

[@stevemonkey6666]

You have explained this concept really well. I have seen other channels try to explain it but not nearly as well.

[@ScienceClicEN]

Thank you very much!

[@GD15555]

the best explanation ever! I think I can build a time machine after watching this

[@ScienceClicEN]

Haha send me an email when you're done I'd be curious to try it

[@joshuaschulze7545]

@@ScienceClicEN Service is spotty. I sent it tomorrow, you should receive it last week.

[@Yerjckk]

I’ve been toying with these ideas, there are huge forces that bend space time and draws objects, like a charming person or a crazy amount of pressure to do something, there are forces beyond light and sound like chemical and mental and they are also black holes in some way

[@RuffianTux]

This is worth a thumbs up just because at no point did he say "nothing, not even light, can escape."

[@StainlessHelena]

This was a phenomenal explanation! The animations are super helpful.

[@AngelGuzman0925]

I’ve watched videos trying to explain black holes and how it works with space time and I’ve always had an idea but this video’s graphics actually make me understand it especially the way it was described! Thank you

[@jackblevins1201]

I love this video. I've learned everything in this video before, but this was a great refresher and the visuals were much more descriptive than in other videos.

[@syiridium703]

Two astronauts fall into a black hole: - "Where do we meet?" - "At five o'clock"

[@ZoggFromBetelgeuse]

At 7:40, part of the light cones are pointing to the left - "backwards in time". What would happen if the trapped astronaut were to point a flashlight towards the singularity? Would the light go backwards in time "for the outside"? Or does the expression "for the outside" become meaningless at a place that can't be observed from the outside?

[@rangelmagalhaes9792]

Uau! Que bela explicação! O cuidado que vocês têm produzindo conteúdos visualmente primorosos me fascina. Parabéns! Vocês me permitem aprender temas muito complexos de maneira muito agradável e bonita!

[@PathfinderMK2]

He explained it better in 12 minutes than my science teacher in 1 hour.

[@teymoorazarpaad9167]

Thanks for describing the light cone so beautifully. Although I couldn’t follow your explanation after minute 9 or so. I must listen to it multiple times for sure to grasp the whole information. Thanks!

[@br7sf8ko4r]

5:50 "if the apple falls, although it was motionless at first, it is because its future points downwards" ... its future points downwards... Maybe I am an apple

[@akskaul]

Great visualisation, thank you! I am unsure what these sentences mean: "the horizon of the black hole is no longer an event in space, but a moment in our past, while the centre of the black hole is no longer a point in space, but a moment in our future". Clearly time and space axes are tilted by the black hole's gravity, but don't they retain their distinct features in that the astronaut can move about freely in space, but has no choice but to move forward in time? Therefore events at the horizon and at the centre must continue to have both time and space co-ordinated associated with them, no?

[@emagdali]

I think what he's trying to say is: Right on the event horizon, the cone always points somewhere inside the event horizon. That means that you can still move freely, true, but only inside the black hole. And if you think of what direction is "up" or "away from the black hole" for you before you enter the event horizon, it becomes clearer. The "away from black hole" is up, where you can move and escape. As soon as you cross it, the direction "away" from black hole doesn't exist as a notion anymore, your light cone is only inside the event horizon. The only notion that exists at that point, is the past event of entering the black hole, meaning that in order to explain where the event horizon is now, you have to use time reference instead of space: the horizon is an event in the past and does not exist in your space. I think that's the product of time and space tilt

[@omargoodman2999]

@@emagdali This is basically it. "Space" is defined as the free motion in any direction, perpendicular to "Time" which is an irreversible trajectory. Inside the Event Horizon, space becomes an irreversible trajectory, thus it becomes "Timelike". By the same process, Time becomes "Spacelike" because, if you tried to "maneuver around" inside the Event Horizon, you could "catch up" to events that occurred before you entered, or "hold up" for future events to catch up to you. You could, effectively, move back and forth through Time, thus, it is "Spacelike".

[@nvmnx6698]

This was the best video i have watched in years, so comprehensive and clear. I am in love with these extremely rare gem-videos where everything is new and nothing is vague. Thank you so much, your work is amazing ❤❤❤

[@mountaindesert34788]

Omggg I've been trying to understand this concept and this video was like turning on a candle in a dark room for me lol. Especially since someone asked on another video why can't light escape a black hole even though it has no mas. And that question fascinated me so I came upon vague answers or too complicated really so this was just what I needed! I see more of why this happens even though it is still a little confusing, I feel so much more clear now! Very well done, so happy I stumbled upon your video randomly in my searches to learn more about black holes 😀

[@ScienceClicEN]

Very happy that it could help you understand better!

[@nguyenvandieu318]

@@ScienceClicEN The video is interesting but i still don’t understand. 11:02 when the diagram is straightened, the new digram doesn’t explain why time can be pulled to the Black Hole’s Singularity like before, which is explained by light cone and that time and space are swapped and easy to understand. Therefore, falling downwards to the Singularity would not be the only destiny, i feel like this part of the video has lost its connection with starting parts if it still bases on time space swapping principle. Something more is why the Singularity is still an event for the astronaut crossed the horizon event. Could you explain those?.

[@Jarlsh]

Here we are, stuck in the inescapable veterinary cone of time.

[@PlanetXMysteries-pj9nm]

"thank you for uploading these videos. Even if I'm having a hard night, I just put a relaxing astronomy video on and listen. It always makes my nights go much easier. Thank you!!!"

[@elegantlechonk]

10:07 this should be a stand ability

[@TryIt42069]

I think my brain just collapsed

[@volcomsocom]

That cone analogy helped me grasp higher dimensions better than the traditional flatland analogy. Props for that.

[@luukv8218]

5:53 I feel like an apple now