General Relativity & Curved Spacetime Explained! | Space Time | PBS Digital Studios
Vložit
- čas přidán 28. 07. 2015
- The Final Installment of our General Relativity Series!!!
Tweet at us! @pbsspacetime
Facebook: pbsspacetime
Email us! pbsspacetime [at] gmail [dot] com
Comment on Reddit: / pbsspacetime
Support us on Patreon! / pbsspacetime
Help translate our videos! czcams.com/users/timedtext_cs_p...
We've been through the first few episodes of our crash course on general relativity, and came out alive! But it's officially "time" for CURVED spacetime. Join Gabe on this week’s episode of PBS Space Time as he discusses Newton and Einstein's dispute over inertial frames of reference. Is Einstein's theory inconsistent? Is gravity even a force??? Check out the episode to find out!
Previous Installments of the General Relativity Series:
"Are Space And Time An Illusion?":
• Are Space and Time An ...
"Is Gravity An Illusion?"
• Is Gravity An Illusion?
"Can A Circle Be A Straight Line?"
• Can a Circle Be a Stra...
"Can You Trust Your Eyes In Spacetime?":
• Can You Trust Your Eye...
Let us know what topics you want to learn more about:
bit.ly/spacetimepoll
Ahh fuck, this is the one channel I'm subscribed to that actually makes me feel like I'm back in high school and I haven't been keeping up with the reading material. Even more than Numberphile and Veritasium, I saw this video in my subscription feed and thought "shit, I didn't fully grasp the final concept of the previous video and this one is out already?" You know when you go into a test knowing you are unprepared? Yeah, that feeling...
MobiusCoin Hehe Agreed! All excited about them uploading a new video but a couple of minutes in and you feel lost.... Realising that you`re not smart as you thought you were
***** I'm like "pppssshhh, General Relativity, I got this. I may not get Quantum Mechanics but I have a firm grasp of Einstein's theories." Turns out NOPE!
MobiusCoin And for that I`m staying away from string theory. My brains will go supernova when I get to close to that!
I know a a bunch of Doctors in Physics that don't grasp both concepts. At least we are trying to understand :D
MobiusCoin I can't belive you just describe my exact situation. Plus I'm looking for some free time to read all references and re-watch all the video series... and maybe finally understand a little about GR.
I'm not fat, my belly is just a geodesic line in a curved spacetime world
Smartest comment ever. Give this man a Nobel.
that still means fat since you need a lot of mass to be able to do that
Red De Cipher You could just be next to a large mass.
@@Prometheus7272 yeah but your mama says she is unavailable
@@AliceTheSpider oof
I just binge watched 6 episodes of Space Time, my brain hurts.
That's a dangerous game you're playing
Naw, it's cool, I can handle...- brain explodes -
lol
Shadow Rider ... Feel the burn. No pain no gain. No need to be ashamed.
Why are you doing this to yourself?
"This is a bit oversimplified..."
Uh...
Yeah... these videos wont teach you about relativity. It's just so much more complicated than that.
You look pretty. So I suppose you to be dumb.
@@shubhamsoni2058 I suppose so, too.
@@jehnabaylon8092 Well I was flirting. There are always exception for that case though. Beauty with brain.
Living proof that it's possible to provide an explanation of something that's *both* simple *and* correct. So many channels get stuff wrong and then the lame excuse is "well we know the real answer but it's too complex for your feeble brain and limited attention span (and this is only CZcams not college)". BULL SHIT. They're just lazy. This video was clearly very tightly worded and shot. The graphics were clear and the metaphors spare and not misleading. I can see the work that went into it and I can't tell you how impressed I am. I wish there was some way to like more than once.
BRAVO, well done! I'm sure I'll be linking to this video in during future discussions on popular science presentations.
ok prove it then, if you understood it explain it layman's terms.
mike jones
Not possible. If YOU didn't understand it, that means that it's just not possible to explain it in layman's terms. That's like asking integrals to be taught like primary school addition.
I'm guessing your head got destroyed by this. Well read "A brief history of time" by the one and only Stephen Hawking. And then come back with enlightenment
Forgive me science for i have sinned, i will read the one and only Stephen Hawkings great book 100 x times until I understand. *drops to floors and kisses your feet* thank you thank you oh saviour!!
@@mikejones-vd3fg It can't really be explained much simpler than in these videos without losing some information. In fact, these videos already lose some information. There is only so much a mortal can do. I do love this little video, too, though (no speaking at all, just words and the graphics):
czcams.com/video/DdC0QN6f3G4/video.html
Greeks:you can't split the atom.. Tesla : you can't split the atom..
Albert...
Greeks: I can see it in my head.
Tesla: I can see it in my head..
Albert:.. Here's some math
Albert: god doesn't roll dice..
Me: waiting for viziv/texzon to charge this mechanism tesla seen.. With the tower he seen.. With the waves He seen .. While you chase variables for formulas because god doesn't roll dice. Trust the governments magician, I'll trust mine.
Don't ever dumb down these videos. They promote that I use my brain and do research which is EXCELLENT
I will do whatever the shit I want to. They deserve to be 'dumbed down' and so do you. And do you honestly think you're using your brain at all??
@@davidwilcox918 what are you on about mate?
Tomas Canevaro my sentiments exactly lol
@@davidwilcox918 what are you even saying lol
They did.
every time he said "in other words" im like "cool im about to understand what this guy is talking about" theeen out comes other words and i still don't get it
Phew, I did it. I still feel like I have so much to learn. Every time I hear people talk about this stuff it seems like it's all so clear in their head. I understand that probably isn't the actual case, but it's a lot better of an understanding than what it is in my 17 year old mind. I cannot wait until I can become older, go to college, and learn about these things for no reason other than to satisfy my inquisitive mind. This stuff is so incredibly fascinating to me, and I want to be able to fully comprehend everything that is humanly comprehensible about this very in depth topic. Can't wait!
Kai Widman I feel you a 100% I can't wait either
Same here except I'm 14 :P
Couldn't replicate my thoughts more (and I'm almost 17 as well)
Why +Enter the Braggn'
+Enter the Braggn' this is the best theory that fits observations. I won't comment with you anymore, since you are probably a troll.
never ever have i been so confused in my life
@@EnSabahNur-ir5mw It does, it's just like someone giving you a two second summary of an intense three hour film. If you've seen the film, or even large parts of it, this will make sense. But seeing the film means putting in the time to learn relativity, and that would defeat the purpose.
But... if you watch these videos each about ten or fifteen times, it will make a bit more sense.
@@EliteTeamKiller2.0 by these videos you mean plural but waigee meant about this one because when it says EXPLAINED person thinks its true, but sad truth is that this is just a clickbait, and you can't learn shit from this guy. He talks really fast, jumps from topic to topic without explaining it to the end, he is bombing you with some facts and never with explanations, because...... you guessed it(maybe) you will have to watch another video, try this one few more times, comment... whatthefuckever and boom, spacetime video has over milion views.
No one will learn shit but that was never his point
I understand about 15% 😅
+1
That's the magic of science you never know unless you feel like your brains gonna have a stroke
Am I the only one that totally didn't understand this?
No, You're not
***** Yarib Suárez Yeah, you're totally not. As usual, these videos are not meant to be digested in one sitting (or even in 10 sittings), and they aren't intended to give a complete explanation. Rather, they're intended to give you a _flavor_ of what general relativity is about and to encourage you to dig deeper without having to get totally lost in the vocabulary.
PBS Space Time quick question if you don't mind but what grade would I be learning this or will I learn it in college (If I take the courses) or do they not teach this is regular school?
Iwon't tellmyname I imagine these concepts would be discussed in an advanced college level physics course. I'm currently taking calculus 1 and will soon be taking physics and I didn't understand some of these concepts/ideas.
WingedSoda Okay thanks. Also good because I'm just going into eighth grade so I got lots of time
I almost cried. This conclusion made everything ever make sense. Thank you
I'll do it. Getting tissue ready
I find this so amazing that i wish i had payed more attention in school instead of trying to understand it now when i'm 20 years out of school. Even though i don't understand everything i feel like i've learned so much from these videos.
momusu17 well we aren't taught these in schools, so I think u r ok lol
@@ArfatXeon but there are a many concepts you should know to be able to understand this well
@@prithishchandna8819 Absolutely
Einstein died about six years before I was born yet somehow I am only truly grasping his work now. I am not uneducated. I have a degree in microbiology and a degree in health sciences. This is a testament to how poor the education system is. I'm grateful to all the materials available on CZcams to bring me up to speed on our current understanding of the universe. Dare I say it, it's almost a religious experience.😂
I dont understand why on physics at high school, they dont start by talking about all of these implications. Like you dont have to get too deep into the math and all, just explain some of the ideas behind advanced physics and what they imply about our universe. Done, all of the sudden I would be hooked! Like they should spend one class, the first class, just talking about this, and then I would probably have paid more attention to all other classes even if they only reached Newton it would still make it so much more interesting!
When the weed is too good
Yaseen Alsaif lmfao
😂
🤣
Just found this series and watched it all twice. I think i somewhat get it and it was truly enjoyable. Eyeopening stuff. Thank you guys so much for doing this.
MIND BLOWN!! I recently stumbled onto this channel a few weeks ago, and I'm hooked. You guys have done such a great job at explaining a complex subject matter and explaining it in a way that can be visualized. It definitely takes a few times to let it sink in, but I've read books and gone to numerous other sources to try and understand these principles better, without getting too much into the math-just to try and understand the basics better-and I'm convinced there is nothing I've found out there that explains it as well as this show. Watching this playlist makes me feel like a little kid again, helping me to see how Santa-'gravity'-isn't what I thought it was made out to be. Keep up the great work.
Slow down. Make it a 30min video if thats what it takes.
Nope. These videos are not meant to be consumed in one sitting. They're meant to be dense knowledge-banks of sorts. You can quickly re-watch them to refer to concepts while you dig deep into the subject on your own
@@thatscnotk No, they are just poorly made. Videos have predetermined dynamics due to the editing as opposed to books, which dynamics are dependent on the consumer. BOOKS are meant to be "dense knowledge banks", not videos. Especially not pop-science videos. The dynamics of these videos is amateur-grade. The editing, while flashy, is totally inappropriate for this kind of content. There are constant animated distractions which serve no purpose except to "look fancy", facts are being bombarded constantly to the viewers without a pause for reflection (when I say "pause" I don't mean blank screen, rather a sequence that is low-density in information) and the host is talking at the speed of light while disregarding the general education of his audience. Look at the comments through all of his videos, you will find the same kind of objections. The Australian guy is much better in my opinion. Or all of the Fermilab videos.
not a lot of people would want to watch it though i just put the playback speed as 0.75
@@brankokosteski
Then press the playback speed button and stop whining
These videos are a very very brief overview.
If you want to delve a little deeper and don't have the time to read a book.
Then, I would suggest watch videos on Tensor and Tensor Calculus by Eigenchris for math background.
Then a video on Einstein field equations on the channel Physics videos by Eugene.
Still you would need books to develop intuition.
GABE!! I GOT IT! I mean, seriously! I tried understanding why gravity is shown as a manifestation of spacetime in many videos before but never understood it(or never was satisfied). Its not that I'm dumb but at almost the end of the video, something inside me struck and everything became clear!! OMG!! I think I have a better way of visualization. Just take a piece of flat paper and draw any straight(to avoid confusion) line on it and a random point. Now, curve the paper about that point. The line, as seen from outside appears bent. If that line is extended along with the paper indefinitely, you could see a path which resembles objects under "gravity". Not just that, if you mark points on the line at regular intervals of time while drawing the line at constant speed, and then curve the paper as we did earlier, you can totally visualize gravitational time dilation as well.
Jesse Jordan I'd have to see what you're drawing to be sure, but that sounds about right. Nice job! Mazel tov! One warning, though -- these kinds of drawings may not be helpful for visualizing how circular orbits can be geodesics. That's a little trickier to translate into a picture (in fact, I don't really know how to do it). But I agree that they kind of diagram you're describing is helpful for visualizing _time_ dilation, yes.
PBS Space Time Ya, practically it may be tough to do but I think it can be visualized. The converse also can be visualized by looking at any diagram of curved spacetime. Take a patch of the curvature and a geodesic(which appears as a circle from above) on it. Imagine stretching the curvature so that it becomes flat(the same spacetime grid should have all vertical and horizontal lines forming squares as viewed from above). The geodesic is now a straight line. Having written this, I realize that this is what you have been telling us from the past few videos about localized parallelism.
Jesse Jordan I'm still not sure we have the same picture in mind (in part b/c I find this very hard if not impossible to picture accurately). But if you have a picture in mind that, even if it's only partially accurate and partially analogy, is still making things "click" for you, then I'm thrilled.
PBS Space Time Tried it out on a pillow just now and realized that it doesn't work. :| The grid lines on the pillow bend inward rather than outward. I think I was imagining coning the paper so that the line bends and meets itself to form a circle. But this may be the wrong way to think about it. I understood what you explained Gabe, and so did I before as well. But I thought everything became crystal clear for some time but I think it's not(although it was worth it). I need to try harder for that visualization but I don't get time! Oh, how I wish I had pursued physics as a career!!
Jesse Jordan My advice -- don't try to visualize this literally. I don't think it works. Instead, try to visualize related things (e.g., whatever you just did with the grid and the pillow, or goedesics on a sphere or a saddle, etc etc) not in the hopes of getting a literal picture but rather in the hopes of finding a loose analogy that helps put your mind in a state that is more receptive to passively transitioning into "getting" the spacetime idea.
It's hard and takes some time, but it can happen. You just have to keep talking to yourself about it and engaging your brain. Not continuously -- that just makes you crazy. But on and off. Don't worry -- you can get there.
So glad the show is making you want to think about this sort of thing.
We should replace "gravity" with "co4st" pronounced (coast) for "Curvature Of 4d Space-Time" or something
BTW, is the ant idea analogy for using a differential?
This is a really good idea. If we spread this the paradigm will change and "gravity" will be superseeded
Nice! A great productive thing I have ever done during holidays! A great mind refresher and to pass time, I have watched each of your video 3-4 times repeatedly to get a better understanding. But still there's a lot to be digested and understood!
Wth, CZcams? I liked this video seven years ago, and I still like it.
Why did CZcams un-like this video for me? I hope I'm still subscribed...
I've watched the whole series like 10 times, and I still don't understand how it's the Earth accelerating into the object. Can someone explain this to me?
DreamOfTitans Lots of people have this question. I tried to explain this better in the comment responses in the subsequent full video (the one about tides -- remember, on this channel, we address viewer questions from episode N at the end of episode N+1, so always look at the _subsequent_ week's vid if you have lingering questions, and they may be addressed there). Anyway, the comments start around '9:58' in the tides video, and I suggest you watch all the comment responses because they're all interrelated, but the issue of Earth accelerating is specifically addressed starting at '13:04' in the tides vid. Link to start of comment section is here: czcams.com/video/pwChk4S99i4/video.htmlm58s. Link to where I discuss the specific question you raise here: czcams.com/video/pwChk4S99i4/video.htmlm4s. Again, though, I'd watch all the comment responses -- everything will probably make more sense.
Also search the page for my comments -- I often address questions here explicitly in writing as other viewers raise them.
+DreamOfTitans The same process of an apple falling to the ground relative to an inertial frame of reference (something stationary) is the same thing as if the apple were the stationary one, and the Earth moving "upwards" toward the apple. It's just an analogy to show you the difference between Newtonian physics and general relativity.
+DreamOfTitans We have to define what an inertial reference frame is first.
My definition of an inertial reference frame is extremely simple.
An inertial frame is one where there is no Doppler Shift in the fundamental forces or at least the minimal shift possible locally (negligible in some volume surrounding the observer).
That is a laser will not red or blue shift when sent from point a to point b in the same reference frame.
When someone accelerates in say a spacecraft ALL the fields in every atom and particle of their body and the space craft blue shifts heading aft and red shifts heading forward. This shifting and stress on all the atoms in our body is what we feel as acceleration. NO blue and red shifting NO feeling of acceleration.
In a gravity well light blue shifts going down and red shifts going up if we remain stationary. That is our bodies feel acceleration even though we are not moving.
The blue shifting and red shifting is also profound in another way. If two lasers have equal frequencies then each cycle of the laser is like a clock (and the two clocks are identical). That is one wave cycle received will correspond a certain amount of time observed. If it was a video broadcast using radio waves there may be 60 frames per second sent via the radio waves. If one observer is receiving blue shifted light and the other red then one observer is receiving MORE lapsed time information than the other one. That is one clock will tick faster than the other one. In this case the one higher up in the gravity well or the one further forward in the space craft. ALL manifestations of time will uniformly tick faster higher up in a gravity well or more forward in an accelerating reference frame. This is Einstein's Equivalence Principle.
A free falling object is balancing its fields and following a geodesic. It would take a force for those fields to red and blue shift as they don't become unequal on their own. Gravity is sometimes not thought of as a force because it does not red and blue shift fields by itself. In the case of people standing on Earth the Earth's surface is providing that force by pushing opposite to gravity.
Calling it "space-time" curvature or saying the Earth is accelerating into the object is a little metaphysical. What we know is occurring experimentally is that we feel acceleration on Earth, we have a red and blue shift in the vertical direction, and a free falling object does not have a red or blue shift. What gravity actually is is unknown. We do know that objects can accelerate relative to other objects in a gravity field AND not experience any red or blue shift (locally).
The simplest way to define an inertial reference frame is by defining it as one not feeling acceleration. With this definition an observer moving at a uniform velocity in flat space is inertial and so is one free falling in gravity. Accelerating frames would be those not free falling in gravity and those with a force acting on them in flat space.
+PBS Space Time Have you ever considered redoing these segments into hour long episodes with tons of examples. It's too fast to follow for us puny mortals.
Ben Russ I mean, if you wanna pony up the funding for that.... ;)
Yay! This is awesome. I agree that the "bowling ball on a rubber sheet" thing is a bit misleading. For the longest time I couldn't grasp how curved *space* resulted in the orbits we see, when such spatial distortion is clearly not directly observable, and light isn't traveling in tight circles around earth just like the moon or satellites, etc. It was only more recently that understanding that the curvature of time (and thus spacetime) was the more important aspect of this that it started to make sense. Thank you for including that, as I'm sure it'll help many viewers. This series is helping to coalesce a lot of the bits and pieces for me too. Thanks!
I don't understand. How does "curved time" make supposedly straight paths look spatially circular like an orbiting satellite? What does "curved time" even mean?
@Nohbd'dy 11, Did you watch the 1960's MIT videos linked from the earlier video in this series about frames of reference? There's one really good bit that made me 'click' about how a guy pushed a hockey puck (i.e. low friction) away from him, and it did a circle and came back around to him.
It was only when you used an 'external' frame of reference, and you could see that the guy / table / puck were all on a rotating disk. What actually looked like the puck looping in a 'circle' was the puck travelling in a straight line, and coming back to the pusher as the pusher had moved (from an outside point of view / inertial frame) to where the puck ended, by rotation of the table (i.e. the pusher's frame of reference).
I can't recommend enough watching the set of 4 videos (~30 mins long). Even though it's almost 60 years old it explains frames of references wayyyy better than I have ever had explained to me, and I feel like it would give you somewhat of an understand of how 'straight' motion can appear curved dependant on the observer's frame of reference.
Here's the video - but please watch it from part 1!
czcams.com/video/3ug23VTMies/video.html
Thank you so much! I've always been to busy to learn GR but this series makes perfect sense and captures the intuition.
Schild's idea is wonderful. So clear and easy to show with a spacetime diagram.
There is no spoon.
Done.
Question answered.
This channel is the best thing that ever happened to youtube.
I can't believe that you guys managed to picture relativity, which is arguably one of the most complex and hard to understand branches of physics (and overall science) so beautifully.
Your videos made me appreciate Einsteins work soooo much more, i can't even express it in words. The implications of Einsteins work of general relativity literally blows my mind now that i have a TRUE and ACUTAL sense of how the universe actually works.
This may seem a little extreme for some people, but i cannot phrase into words how thankful i am for your videos and how beautiful all the previous videos converged into this final one to make a sense of it all.
I fucking love science and i fucking love you guys for making the concept of relativity and spacetime so tangible for people like me.
I agree with you, these videos convinced me to take physics based education
Relativity is not hard to understand. It just requires a lot of mathematics. As a mathematician who knows relativity, I can assert to you that if you understand Semi-Riemannian Geometry, then General Relativity is a fun exercise.
7 Months later, I am finally getting closer to entirely grasping General Relativity. Hurray! And that's without any educational background in math or science. Believe in yourself and keep trying, improve your thinking and you will eventually understand it.
Watching videos of and reading into big bang, protons, neutrons, electrons, quarks, nuclear fission and fusion, formation of stars, and big bang has helped me understand the theory. Also realizing everything is simply made out of energy has opened my mind. The universe is marvelous.
Man, I always thought I was pretty sharp until I started watching these. I can understand some of the pepperoni and mushrooms, but the pizza escapes me. I guess that's OK for having zero formal education in physics though.
Yea same but thats why I like them
I don’t know if you studied more in the last 4 years since you posted this comment. A good place to start with general relativity would be time dilation and length contraction.
@@smokey04200420 I can't grasp the concept I heard somewhere, which stated that an object, placed inside curved spacetime, trades its temporal speed for speed through space, which ultimately accelerates it in a straight line, which is actually a geodesic. So if I'm an inertial observer suddenly placed in a curved spacetime, how do I start accelerating through space?
I don't know if that makes sense, I tried my best...
@@thrash1337 then don’t think of it like that. I never have. I never even thought to think of it like that until just now that I read your reply. But it make sense. When you accelerate, your clock slows down relative to the entire universe. You’ll see the universe speed up and everyone else in the universe will see you slow down.
Think of it this way instead:
Everything travels at the speed of light through spacetime. Light travels through space at the speed of light, but it doesn’t travel through time (in the frame of a photon, it exists for an infinitesimal moment equivalent to zero). In an inertial observer’s frame (someone who is not accelerating) the observer is not traveling through space, therefore is traveling through time at the speed of light.
A non-inertial observer (someone who is accelerating or in a gravitational well) is somewhere in between. They are traveling through both space and time less than the speed of light in each, but at the speed of light through both.
Therefore you need to give up some of your time travel to put it toward accelerating through space.
@@thrash1337 Think of spacetime as a fabric. When you put something with mass, like a planet, onto the fabric, the fabric warps, stretches and curves the same way a trampoline curves to accomodate a bowling ball. Not only space is curved or stretched, but also time. Time on earth is more stretched out compared to time in the vacuum of space. So, from the perspective of someone in space, a person's clock on earth ticks slower. But the person on earth perceives time normally.
As for the acceleration through space, lets go back to the bowling ball on the trampoline analogy. If you roll a marble onto the trampoline, it rolls relatively slowly at first, but the closer it comes to the bowling ball the faster it accelerates because it's rolling downhill into the heavy mass of the bowling ball. So it's speeding through space (This is literally gravity). But remember what I said about time also being stretched. So you're speeding through space but experiencing less time when you do it. You're trading speed through time for speed through space.
Did that make sense? I think that's how it works.
This viseo was amazing and well explain for most of the night I was confuse my head was spinning but thank to this video now I really understand now, your explanation was fabulous thank you very much pbs.
"There is no spoon" - ha! Nice reference.
Lucas Balaminut I don't understand it. Would you mind explaining what he means when he said it?
Spoonman is the new Guy Fawkes.
Came to the comments section to see if anyone else caught that. It’s a reference to the move The Matrix. Google “there is no spoon” and you will see clips of the scene in the video results.
Well, said! One of the best explanations I have heard. I can count them on one hand. Thank you!
I decided to pick the hardest topic we could do for a project so i have to describe general relativity, special relativity, dark energy, and Einstein's rosenbridges and I have to explain what all of them are and the equations. Im in 8th grade. This is literally killing me. This is a good video that actually helps so thanks for making it!
Hello There oh wow if u really are an eighth grader, I admirer ur curiosity, don't listen to what others to say, it's the mathematics that's hard, the intiuition is easy, once u get used to it. Problem is, others get so used to Newtonian Mechanics which is y GR looks unintuitive to them. If u can get used to the ideas of GR at a young age, u will do much better later on
I again reffer you to this video to give a more visual representation of the ideas presented here:
czcams.com/video/jlTVIMOix3I/video.html
Yair Eshel Recommended.
+Yair Eshel Highly recommend!
+Yair Eshel Goof video, but he totally got the part about bending time wrong.
As gabe just said, gravity as actually mostly a result of time bending, while space stays relatively flat
+Yair Eshel Highly recommend.
video is no longer available
These are awesome. Thanks!
The ant mistake: In my school years we did a distance measurement over ca 5 km(with tachymeter) which ended at the point we started. When drawing out the data on paper we could not get the start- and endpoint to match, even after triple checking the data they would not match (while our data proved correct, >95% accurate). Now 10 years later I realize I made the ant mistake; not taking the curvature of the earth into account. WoW!!! Thnx SpaceTime. :) :) (now to figure out the rest of this series, lol. I will rerun them till I get it. :P
finally!!! somebody figured out how to explain this- and super fast!!!! what a relief. Thank you guys so much
physicists have unified three of the four forces of nature; the only one eluding them is gravity. but if gravity is an illusion then it is not a force and so scientists have already unified all of them.
+Phil V
Not really, when we say we haven't unified all the forces, what we mean is, we cannot use the same equations as we do for explaining the nuclear and electromagnetic interactions (quantum field theory) to explain "gravity" or more technically "Space time curvature". We need to refer to Einstein's equations of general relativity to figure out the curvature as explained in the video.
Thus we still haven't unified QFT with GR or (the three fundamental forces with "gravity")
+Phil V Now that's the kicker. GR and QT conflict on this matter. GR states that gravity is not a force, but guiding particles along the spacetime curvature creating 'gravity'. QT is about effects on particles caused by 'messenger' particles. W and Z bosons 'message' the weak force, gluons carry the binding force between quarks and - theoretically - gravitons attract mass. The problem is, they never found gravitons so Einstein is still right. If they ever do find gravitons then the physics world would have another revolution. IF... They simply don't know if those things exist.
Amazing as usual. Relativity is kinda my thing and you do a very good job with it. A couple (slightly off topic) questions though:
1) I always read that when you use quantum mechanics and general relativity together, you get unrealistic results like zero or infinity. However, I've never seen any of the math that shows this. I used them together in my masters thesis (about white dwarf stars) many years ago without much trouble. Do you know of any sources that run into this problem?
2) How did you get linked up with PBS before you even started making videos?
PBS Space Time P.S. I just went through the comments and answered a few of your viewer's questions. Hope you don't mind :-)
i came here because of your black holes episode only to find you again.
@@ScienceAsylum it's okay to be a little crazy haha..bumped into your channel a few months ago and I got into this rabbit hole that I have fallen in love with
Historical Facts - Citations
CITATION FROM „Reactionaries and Einstein's Fame: “German Scientists for the Preservation of Pure Science,” Relativity, and the Bad Nauheim Meeting
Jeroen van Dongen
Einstein Papers Project California Institute of Technology Pasadena CA 91125, USA
Institute for History and Foundations of Science Utrecht University P.O. Box 80.000 3508 TA Utrecht, the Netherlands“
FACTS to 1918:
6 he has stolen the work of others and has mathematized physics to such an extent that fellow physicists have been left clueless. Furthermore, the article continued, Einstein had undertaken a propaganda campaign by which he had cast a spell both over the public and over academic circles--but in reality relativity was nothing but fraud and fantasy. The author of the piece was Paul Weyland (1888-1972, figure 1), an obscure right-wing publicist and talented rabble-rouser-- one of the shadier products of postwar Berlin.
8 Weyland also drew heavily on Lenard's more substantive objections to Einstein’s theory of relativity, which Lenard had published in 1918.
10 but Weyland contended that they had remained undisputed. Weyland’s shrill tone in his newspaper article and the highly public character of his accusations were indeed new, however. Also new was their thinly concealed anti-Semitic character: Weyland claimed that Einstein had “a particular press, a particular community [Gemeinde]” that kept feeding pro-Einstein stories to the public. enough: The widely circulating, liberal Berliner Tageblatt was published by Rudolph Mosse.
FACTS (1919 - 1920) :
Professionally non educated EDITORS ( non physicists ) and private owners of newspapers perpetrate really serious immoral act in science by that it hinders its natural development and creating an deceitful picture of Albert Einstein by his glorification:
12 In 1919 it had carried an article [13 autor Alexander Moszkowski (1851-1934), 15 editor-in-chief was Arnold Berliner (1862-1942)] announcing the results of the British solar eclipse expedition that rose to laudatory hyperbole, not shying away from declaring that “a highest truth, beyond Galileo and Newton, beyond Kant” had been unveiled by “an oracular saying from the depth of the skies.”
16 on December 14, 1919, the front page of the Berliner Illustrirte Zeitung [17 This newspaper had been founded by Leopold Ullstein (1826-1899)] carried a large close-up portrait of Einstein whose caption read: “A new eminence in the history of the world: Albert Einstein, whose researches signify a complete revolution of our understanding of Nature and whose insights equal in importance those of a Copernicus, Kepler, and Newton.”
2 The huge public acclaim that was accorded Einstein. It also vexed conservative academics (e.g. the Nobel Laureate Philipp Lenard have felt that the theoretical physicist Einstein had captured too much of the limelight, while other, experimental physicists were not appreciated enough.)
FACTS Then followed (1920):
Reactionaries and Einstein's Fame: “German Scientists for the Preservation of Pure Science,” Relativity, and the Bad Nauheim Meeting
Jeroen van Dongen
Einstein Papers Project California Institute of Technology Pasadena CA 91125, USA
Institute for History and Foundations of Science Utrecht University P.O. Box 80.000 3508 TA Utrecht, the Netherlands
Two important and unpleasant events occurred in Albert Einstein’s life in 1920: That August an antirelativity rally was held in the large auditorium of the Berlin Philharmonic, and a few weeks later Einstein was drawn into a tense and highly publicized debate with Philipp Lenard on the merits of relativity at a meeting in Bad Nauheim, Germany.
73 Nonetheless, tensions had been mounting. Max Planck was firmly in the chair, but prior to the debate--because he was still not certain whether Einstein would remain in Berlin--he appeared to be quite agitated.
74 Paul Weyland also was present at the debate--but this time he kept a low profile. Einstein and his wife Elsa were strongly affected by the exchange: Elsa suffered a nervous breakdown.
75 The Viennese experimental physicist Felix Ehrenhaft (1879- 1952) recalled that he had to take a highly upset Einstein out for a calming stroll in the park after the debate. Later that evening they avoided the uneasy company of their fellow physicists.
76 Both Lenard and Einstein left the conference deeply distressed. Lenard renounced his membership in the DPG--and even denied admittance to his office at the University of Heidelberg to any of its members.
Albert Einstein und Philipp Lenard
Dr. Charlotte Schönbeck
Pädagogische Hochschule Heidelberg
Fakultät für Mathematik und Naturwisse
For nearly 100 years ago have been Nobel Prize winners said:
The theory of relativity is a mathematical and not a physical theory.
The theory is far from being confirmed experimentally, the results of the solar eclipse expeditions allow other interpretations
The principle of relativity is only valid for mass-dependent movements
The theory of relativity contradicts the fundamental ideas about space and time: the Euclidean space and the usual ideas of time must remain binding.
What is Einstein´s closed vicious circle ?
DOI: 10.13140/RG.2.2.24875.18722
Projects: How to make Theoretical Physics valid for the longest
Science from History to Future
Both the Special & General theory of Relativity have been verified to high precision by a
multitude of experiments only in Einstein´s closed vicious circle:
Lorentz transformation equations local time
local time covariant equations
covariant equations physical definition of simultaneity
physical definition of simultaneity invariant interval
invariant interval Lorentz transformation equations
is valid for all ... is valid for everything, is valid for any stupidity, is valid for any information.
Special & General theory of Relativity not valid in real Universe.
Change QUALITY
1905 A.E. : Einstein ´s theory Tkin =mc^2 - mo c^2
1996: Tkin id =mc^2 [ln |1-v/c|+ (v/c) / (1-v/c) ]
Tkin ad = mc^2 [ln |1+v/c|- (v/c) / (1+v/c) ]
Einstein's theory works only for v < 0.1c.
REFERENCES
[1] KAUFMANN, W.: Annalen der Physik, Vierte Folge, Band 19, Leipzig, 1906 Verlag von Johann Ambrosius Barth p. 487-552
[2] EINSTEIN, A.: Sobranie naučnych trudov v četyrech tomach pod redakciej I. E. TAMMA, Ja. A. SMORODINSKOGO, B. G. KUZNECOVA, Izdateľstvo "Nauka", Moskva 1966
[3] FIZEAU, M. H.: Sur les hypothéses relatives a l’éther lumineux. Ann. de Chim. et de Phys., 3e série, T. LVII. (Décembre 1859) Présente á l’Academie des Sciences dans sa séance du 29 septembre 1851.
[4] KNOPF, O.: Annalen der Physik, Vierte folge, Band 62, 1920 :"Die Versuche von F. Harress uber die Geschwindigkeit des Lichtes in bewegten Korpern, von O. Knopf. p. 391 - 447
[5] PURCELL, E. M.: Electricity and magnetism. In: Berkley physics courses (Russian translation). Moskva, Nauka 1971.
[6] FEYNMAN, R. P. - LEIGHTON, R. B. - SANDS, M.: The Feynman lectures on physics (Russian translation) Moskva, Mir 1965-1966.
[7] Vlcek, L. : New Trends in Physics, Slovak Academic Press, Bratislava 1996,
ISBN 80-85665-64-6. Presentation on European Phys. Soc. 10th Gen. Conf. - Trends in Physics ( EPS 10) Sevilla , E 9. -13 September 1996,
Critical examination of fundamentals in physics
www.trendsinphysics.info/
tuke.academia.edu/LubomirVlcek
www.researchgate.net/search?q=Lubomir%20Vlcek
vixra.org/author/lubomir_vlcek
Historical Facts - Citations
CITATION FROM „Reactionaries and Einstein's Fame: “German Scientists for the Preservation of Pure Science,” Relativity, and the Bad Nauheim Meeting
Jeroen van Dongen
Einstein Papers Project California Institute of Technology Pasadena CA 91125, USA
Institute for History and Foundations of Science Utrecht University P.O. Box 80.000 3508 TA Utrecht, the Netherlands“
FACTS to 1918:
6 he has stolen the work of others and has mathematized physics to such an extent that fellow physicists have been left clueless. Furthermore, the article continued, Einstein had undertaken a propaganda campaign by which he had cast a spell both over the public and over academic circles--but in reality relativity was nothing but fraud and fantasy. The author of the piece was Paul Weyland (1888-1972, figure 1), an obscure right-wing publicist and talented rabble-rouser-- one of the shadier products of postwar Berlin.
8 Weyland also drew heavily on Lenard's more substantive objections to Einstein’s theory of relativity, which Lenard had published in 1918.
10 but Weyland contended that they had remained undisputed. Weyland’s shrill tone in his newspaper article and the highly public character of his accusations were indeed new, however. Also new was their thinly concealed anti-Semitic character: Weyland claimed that Einstein had “a particular press, a particular community [Gemeinde]” that kept feeding pro-Einstein stories to the public. enough: The widely circulating, liberal Berliner Tageblatt was published by Rudolph Mosse.
FACTS (1919 - 1920) :
Professionally non educated EDITORS ( non physicists ) and private owners of newspapers perpetrate really serious immoral act in science by that it hinders its natural development and creating an deceitful picture of Albert Einstein by his glorification:
12 In 1919 it had carried an article [13 autor Alexander Moszkowski (1851-1934), 15 editor-in-chief was Arnold Berliner (1862-1942)] announcing the results of the British solar eclipse expedition that rose to laudatory hyperbole, not shying away from declaring that “a highest truth, beyond Galileo and Newton, beyond Kant” had been unveiled by “an oracular saying from the depth of the skies.”
16 on December 14, 1919, the front page of the Berliner Illustrirte Zeitung [17 This newspaper had been founded by Leopold Ullstein (1826-1899)] carried a large close-up portrait of Einstein whose caption read: “A new eminence in the history of the world: Albert Einstein, whose researches signify a complete revolution of our understanding of Nature and whose insights equal in importance those of a Copernicus, Kepler, and Newton.”
2 The huge public acclaim that was accorded Einstein. It also vexed conservative academics (e.g. the Nobel Laureate Philipp Lenard have felt that the theoretical physicist Einstein had captured too much of the limelight, while other, experimental physicists were not appreciated enough.)
FACTS Then followed (1920):
Reactionaries and Einstein's Fame: “German Scientists for the Preservation of Pure Science,” Relativity, and the Bad Nauheim Meeting
Jeroen van Dongen
Einstein Papers Project California Institute of Technology Pasadena CA 91125, USA
Institute for History and Foundations of Science Utrecht University P.O. Box 80.000 3508 TA Utrecht, the Netherlands
Two important and unpleasant events occurred in Albert Einstein’s life in 1920: That August an antirelativity rally was held in the large auditorium of the Berlin Philharmonic, and a few weeks later Einstein was drawn into a tense and highly publicized debate with Philipp Lenard on the merits of relativity at a meeting in Bad Nauheim, Germany.
73 Nonetheless, tensions had been mounting. Max Planck was firmly in the chair, but prior to the debate--because he was still not certain whether Einstein would remain in Berlin--he appeared to be quite agitated.
74 Paul Weyland also was present at the debate--but this time he kept a low profile. Einstein and his wife Elsa were strongly affected by the exchange: Elsa suffered a nervous breakdown.
75 The Viennese experimental physicist Felix Ehrenhaft (1879- 1952) recalled that he had to take a highly upset Einstein out for a calming stroll in the park after the debate. Later that evening they avoided the uneasy company of their fellow physicists.
76 Both Lenard and Einstein left the conference deeply distressed. Lenard renounced his membership in the DPG--and even denied admittance to his office at the University of Heidelberg to any of its members.
Albert Einstein und Philipp Lenard
Dr. Charlotte Schönbeck
Pädagogische Hochschule Heidelberg
Fakultät für Mathematik und Naturwisse
For nearly 100 years ago have been Nobel Prize winners said:
The theory of relativity is a mathematical and not a physical theory.
The theory is far from being confirmed experimentally, the results of the solar eclipse expeditions allow other interpretations
The principle of relativity is only valid for mass-dependent movements
The theory of relativity contradicts the fundamental ideas about space and time: the Euclidean space and the usual ideas of time must remain binding.
What is Einstein´s closed vicious circle ?
DOI: 10.13140/RG.2.2.24875.18722
Projects: How to make Theoretical Physics valid for the longest
Science from History to Future
Both the Special & General theory of Relativity have been verified to high precision by a
multitude of experiments only in Einstein´s closed vicious circle:
Lorentz transformation equations local time
local time covariant equations
covariant equations physical definition of simultaneity
physical definition of simultaneity invariant interval
invariant interval Lorentz transformation equations
is valid for all ... is valid for everything, is valid for any stupidity, is valid for any information.
Special & General theory of Relativity not valid in real Universe.
Change QUALITY
1905 A.E. : Einstein ´s theory Tkin =mc^2 - mo c^2
1996: Tkin id =mc^2 [ln |1-v/c|+ (v/c) / (1-v/c) ]
Tkin ad = mc^2 [ln |1+v/c|- (v/c) / (1+v/c) ]
Einstein's theory works only for v < 0.1c.
REFERENCES
[1] KAUFMANN, W.: Annalen der Physik, Vierte Folge, Band 19, Leipzig, 1906 Verlag von Johann Ambrosius Barth p. 487-552
[2] EINSTEIN, A.: Sobranie naučnych trudov v četyrech tomach pod redakciej I. E. TAMMA, Ja. A. SMORODINSKOGO, B. G. KUZNECOVA, Izdateľstvo "Nauka", Moskva 1966
[3] FIZEAU, M. H.: Sur les hypothéses relatives a l’éther lumineux. Ann. de Chim. et de Phys., 3e série, T. LVII. (Décembre 1859) Présente á l’Academie des Sciences dans sa séance du 29 septembre 1851.
[4] KNOPF, O.: Annalen der Physik, Vierte folge, Band 62, 1920 :"Die Versuche von F. Harress uber die Geschwindigkeit des Lichtes in bewegten Korpern, von O. Knopf. p. 391 - 447
[5] PURCELL, E. M.: Electricity and magnetism. In: Berkley physics courses (Russian translation). Moskva, Nauka 1971.
[6] FEYNMAN, R. P. - LEIGHTON, R. B. - SANDS, M.: The Feynman lectures on physics (Russian translation) Moskva, Mir 1965-1966.
[7] Vlcek, L. : New Trends in Physics, Slovak Academic Press, Bratislava 1996,
ISBN 80-85665-64-6. Presentation on European Phys. Soc. 10th Gen. Conf. - Trends in Physics ( EPS 10) Sevilla , E 9. -13 September 1996,
Critical examination of fundamentals in physics
www.trendsinphysics.info/
tuke.academia.edu/LubomirVlcek
www.researchgate.net/search?q=Lubomir%20Vlcek
vixra.org/author/lubomir_vlcek
How am i seeing this now for the first time. This is the best video of this kind ever made about this topic
Wow! This miniseries was a great explanation I really think I understand it a lot better. It definitely helped to rewatch every video
3:20 It is at this point that everything becomes so much clearer to me. My god.
Nicholas Mew You mean "According to Einstein, Newton is making the same mistake as the ant"? That's what made the light bulb turn on for you? I'm curious, because I'm not especially good at predicting what will make things "click" for viewers.
PBS Space Time It is because at this point the entire thing about space time being curved just became clearer and more comprehensible to me. It is hard to explain. I am sorry if i cannot explain any further.
Nicholas Mew I agree. That helped me and also the picture of wrapping a rectangle on a globe.
1.YES I got it
2. I'm really sad you're not gonna be my physics teacher anymore :(
Watching "Why GRAVITY is not a Force" by Veritasium and then coming back to this helped me understand things a lot better than before.
Took me rewatching all of the previous videos twice, and making it this far to actually understand any of it... but holy heck, I think I actually got it!
Why are physicists looking for evidence of gravitons, the force-carrying particle of the force of gravity, if there is no force of gravity?
Yeah, what he says! Why???
cavalrycome Johan 't Hart This question is asked a lot. See this reply that I left for another viewer on another episode: czcams.com/video/NblR01hHK6U/video.html&lc=z12ed1mhjnarclqel22xzpdhgsenu1dih04
Best on youtube
I enjoyed this series. The more we acknowledge that spacetime has tangible, real properties, the sooner we will recognize that it is much more than a vacuous nothingness. If it is not nothing, it must be something...and all of a sudden, we realize why all of the underpinning concepts underneath Relativity were crafted from an Aethereal perspective.
Asesome series all of the guys from this channel are really good explaining, but this one really is the best one
I feel my earth was flat prior to watching this video, my reality has been expanded. Schools must teach this mandatorily.
Well, your Earth wasn't flat but your space-time certainly was! :-)
All the best.
That is litterally the stupidest thing ive ever heard...just no
Another one of those anonymous guys, come on what so thrilling about them anyway, hacking kinda amazing and some what not good but they nothing special about these dudes.
When you say (and I'm paraphrasing here): "Gravity is, in reality, the manifestation of the curvature of spacetime due to energy density", I understand from it is that this "force" is actually a result from a property of spacetime itself. Why ,therefore, are gravitational waves ALSO bound to the speed of light limit?
And also, how do you reconcile this with the concept of fundamental forces (of which Gravity is supposed to be part)? Do you think we're going to witness a day where the remaining forces will be proven to also to be resulting from properties of spacetime? And if so, do you agree that it follows from it that all of matter/energy interactions (history) are resulting from spacetime itself (the stage is the puppeteer)?
Sehail Fillali Question 1 (about the propagation speed of gravitational waves) is a whole topic unto itself, and it requires first talking about what gravitational waves even *are*. Question 2 is similar to a question others are asking on here about gravitons. Browse the comments to see my replies there.
PBS Space Time I forgot to thank you for doing all this. I cannot thank you enough for making this material accessible to us. I feel as if I was illiterate and you taught me to read. You and your team are the real MVPs.
One more tiny question? Why would an apple that suddenly appears in the vicinity of earth start moving towards it in the first place? Does it have to in order to keep a constant 4-velocity?
PBS Space Time Can we humbly request that a future episode touch on what gravitational waves are?
Why is everyone saying he speaks too fast?
I think it is great. Cover a massive amount of material in a short time.
If it is too fast for you, you can slow the video down in the setting, pause it or even replay it.
So if you complain about it -- it means you are an idiot.
god damn it! i had you till the mids of this episode and was feeling super cool!
Your video states near the end:
"Most of the every day effects on earth that Newton would attribute to gravity are due to curvature in TIME. The 3D space around earth is almost exactly Euclidean. ...... Around earth, spacetime curvature manifests itself in clocks much more than in rulers."
This is very interesting to me. So the weight I feel as I stand on the earth is caused by a curvature in TIME? If you could please elaborate on this more, I would appreciate it. I am not able to entirely understand how time is causing the earth to accelerate upward into me.
If you consider that Earths mass makes time to be perceived by an GPS satelit different with a nanosecond/day from one that is standing on the sourface of Earth, then if you do your math you will see that Earths mass curves space like 10 to the power of minus a number.....so very little. Thats way space around the Earth is pretty much flat (euclidian way)....So the effects of gravity=curved spacetime appear for us in fact due to the curved time ...because the effect of bending time are far greater than those occurs to space .being bent.
Think of it this way: if you send a laser beam from Earth, it is mostly straight, Euclidean line, it doesn't get deflected by Earth gravity in any measurable way. That happens because light leaves curved space-time area 'very quickly'. It's gone 10 000 kilometers spatially and just the same by the time axis (its world line is always 45 degrees inclined), not so much.
But now consider throwing a rock upwards. It travelled just several meters spatially, but it's gone by 'fourth dimension' millions of kilometers 'forward in time'. Remember, when bodies are moving slow, we can say that they fly forward in time with speed of light, 300 000 km/s. So our rock has gone millions of kilometers of curved space-time and that was finally enough to make a difference, so it got deflected just several meters and gone spatially down, to Earth, instead of up.
AllMyCircuits according to Einstein and according to this video The Rock does not go down it's the Earth that accelerates upward into the Rock. therefore I have no idea why you are saying the rock goes down.
I don't understand why on this video they say that exactly Earth accelerates upward into the rock. We have general RELATIVITY after all, and after all it means 'everything is relative!' We may look at situation from reference frame of rock or equally well from reference frame of Earth and get absolutely same result.
My best 'mental image' of process is: all the bodies travel forward in time at speed of light (if they are rather slow, it applies to almost everything except light). If there were no gravity, we would put rock coupl of meters over the Earth, leave it and they wouldn't move toward each other at all, that is, they both travel by straight parallel lines into the future. We have Euclidean space there (or should I say Minkowsky space-time, still flat) where parallel lines don't intersect.
But when gravity works (I mean, mass and energy curve space-time), Earth and rock still travel by parallel lines, but our geometry has changed, so these parallel lines intersect after all! And why we say about curvature in TIME is: we had to travel millions kilometers into the future (it took several seconds, but whatever) and only than we felt little difference: couple of meters of spatial distance changed and our two objects met after all.
The rock its NOT in free fall! Not for the first parth of the ride up.
Sir ... I got headache after watching it and trying to understand it... sir, please make it more easy so that peoples like me can understand it...😊❤ thank you
30 years ago as a hotshot PhD student in chemical engineering, I started to read Wolfgang Pauli's book on relativity and then a book by Einstein. I really thought it was possible for me to figure it out and understand it from a mathematics standpoint. Boy was I really a jerk! I am 57 now, still stumped, but watching videos like this has really helped with my understanding of the high points. My hat is off to you physicists who do research in stuff like this, while I design wastewater plants haha!
I miss him! This is the best explanation on the spot I have ever seen.
"There is no spoon "
well, to hell with this fuckery!
How does the image of the black hole at the centre if M87 factor into the arguments and the proof of general relativity?
ever seen a black object emit light? why would a black object emit light? sun emits light but sun's not black.. stars emit light but they are not black... Why does this object discovered on 10th April seems to emit light? The only explanation is, that black object is reflecting light from distant galaxies to us, sort of a mirror.
General Relativity tells us it's possible. That black object curves space-time around it that it can even bend light. That's why it seems to be luminous.
@@99bits46 well, it's not emitting light. The image that was released is that of the shadow of the black hole in the backdrop of a huge amount of luminous dust. The 'black object' is a black hole. It's the densest thing in the universe. No light can escape or reflect from it 😅 otherwise the picture released wouldn't be such a big deal. We would've been able to click it's picture way back if it did reflect light like a mirror
@@vishwangdave7785 yea it doesn't reflect but bends light around it.. besides the surface of this black object is always black so what is the light source for that ring. GR explains that.
Salman Memehood The light source of that ring is the accretion disk, the ring IS the accretion disc: Matter forming a disc and spiralling around the black hole emitting light. GR predicted how the image would look, and that's that
Vishwang Dave did Neil degrasse Tyson tell you that?
That's amazing. I got the eureka moment. If two photons are fired from a clock and the bottom of a building into the roof, the lines of that photon on a graph would have to be parallel and congruent along with the space between the arrival from the first and second photons along the departure and arrival. Since the departure is congruent and the arrival non congruent we must conclude that Einstein is correct and space time is curved because the clock ticks are at a different rate. Amazing.
And half a year later after this video was released, gravitational waves were proved to exist!
And, last week they won a nobel prize for the discovery :D
If the force of Gravity is really a perception of geometry, are the other "forces" also the result of not-actually-a-force?
Thank you.
Michael Winter I have been thinking about the same thing
Or are there forces which we have so far not noticed , believing them to be side effects of something else ??
No, they have particles as carriers. What is often called gravity, warped space, has no discovered particle. So, unofficially, there are three fundamental forces.
I saw a woman with such beautiful curves, she warped the space-time in my mind.
Suave
Bassotronics, I don't think you have a mind to warp.
Damn
but that would also assume that she has a great gravitational pull which means that you're calling her fat (general relativity explains that gravity is a warp in space time ). Nice try bro.
@@hghg46204 don't worry; mass is an effect, she's not fat, she just has a lot of energy
I think the issue for a lot of people is that they think about bent space in 2D. The bending of space is minimal. What makes object fall is mostly bending of time. In other words objects travel the shortest path into the future (that is unless something like floor stops them). For example an object falling into a singularity will take the shortest path into the future of the universe while outside observers will have to wait trillions of years.
thank you for concentrating on the curvature of time being dominant in readings!!!!!
Could he talk a little faster? I almost understood some of that! :)
put playback speed as 0.75
Dude would make a great auctioneer.
my brain's fried like a dried prune & i love this ...next time could u please explain/remind us of the vocab terms again from the previous 4 episodes, thanks!
Excellent video :) I do like the topic and how it far exceeds the simplistic way of thinking in 2D. I also finally see the link with integrals that put the ant on infinitely small planes.
I tried to bend space time, but I broke my screen.
So if gravity is not real, will a graviton particle never be discovered?
lkampy10 Many people asking this question on here and on other episodes. Look elsewhere for my (not especially satisfying) reply.
Actually "Curvature Of Four Dimensional Space Time" sounds like an awesome band name (y)
Amazing series, thank you!
The spoon isn't real- did you just reference the matrix
R dog 123 I dunno.... did I? And do you think that's -air- gravity you're -breathing- experiencing?
PBS Space Time Amazing.
PBS Space Time you're actually freakin' awesome.
please keep up the great work, that goes for you and all the researchers, editors, etc working on PBS Space Time!
your videos always restore my faith on humanity's educational future.
PBS Space Time I don't get it; this video seems to make perfect sense to me, even after only watching it a single time, but when I try to get these words to make sense I fail every time.
Video is just amazing.. But I was thinking about flat earthers.. Uff How far behind are they???
Are they beyond us? because the universe is actually flat
Why are u so concerned about them?
Thank you so much, Gabe. I understand and it is an amazing feeling.
I've heard the curvature of spacetime described as "near heavy objects, time points just a little bit down." I've always liked that.
It's incredibly difficult to absorb complex information like this from someone who doesn't breathe! It's like a computer reading out the script at 3x speed. I need a lie down.
MIND .... BLOWN....
this whole 5 episode "series" (can it even be called a series?) just explained EVERYTHING.... to me........ a dumbass.......
thanks!
I love watching these videos even though I'm lost on the math parts. I failed algebra so bad my freshman year they pulled me out after the first 6 weeks. Ended up taking geometry which, oddly enough, got an a. Must have something to do with being able to visualize the problem.
Hi thanks for the videos. Need to watch again and let it soak in. I'm curious how would a quantum theory of gravity affect all of this?
I put it on 2x nows he's new rap God 😎😎
So why are physicists looking for gravitrons if there is no gravity!?
Joe Fasano Look elsewhere on the comments page for my response (which is unsatisfying). This seems to be the top question viewers have after watching today's vid.
They did´nt understand Einsteins 4D spacetime.
So finally, its the earth which accelerates towards the apple... but I guess a lot of apples must be falling (....eh no not falling) at the same time and mother earth must be going mad trying to get to all of them at the right time!
Relativity
Is
Weird!
But I like it!😉✌
And one thing to mention, spacetime is my fav youtube channel!
I hate myself for not really understanding more than half of this video but spending most of my time on social media and mundane stuff when such topics like this are so interesting and meaningful but yet ignored. I hope one day to be a different person and understand at least the basics of astronomy and physics.
i made speed to 0.5X still did not understand
Maybe it's just Me.. But I've watched quite a few of your videos now, and I find at the end of each one I've learned next to nothing. You need to speak a little slower, and make video a little longer if that's what's needed to provide some actual knowledge with substance. I find every video follows same formula with: State the micro-concepts that make up the "Macro-concept"; but never actually EXPLAIN the "micro-concepts", and therefore making a cohesive understanding of how the sum of parts make up the whole not possible.
Easier said than done
I tend to break the videos down point by point, concept by concept, If I don't understand one I rewind and rewatch it a few times, then stop watching the video and go on with my day. Then I think about the point/concept now and again in my day and then come back and rewatch it again, the majority of the time it clicks then
I think if they made the videos like that it would not be digestible and most people would find it boring. However I agree with you, and it is annoying to have to look stuff up separately for each video.
It is fast, but they are beautifully described
I usually pause the video and think until i get it, then i unpause and watch on
don't take this the wrong way, but this isn't live. You can slow down the speed of youtube videos and take notes. If the video was longer more than half the people would not even watch it.
Nice and undertandable explaination, realy liked it, good job.
By the time I start to process what he said he's already on to the next portion and I'm lost again. So I'm constantly having to rewind and rewatch and rewind and rewatch. And I'm tired of it so I just try to watch it all the way through and get whatever I can.
This video: *exists*
Newton: Am I a joke to you?
I clicked because I wanted to know some cool knowledge but...
What. The. Heck.
Omg, I think I finally understand this messy super interesting concept!
Video was awesome!!!
Since I am not a physics expert, I couldn't grasp all of it but whatever I understood from that I have following observations: -
1. Since at the beginning of video surface accelerating towards apple analogy was given and it is very well discussed by frame of reference !!
but if we think in normal terms (i.e., what we can see) then surface accelerating towards apple will kind of give impression some radially upward force
from surface to apple giving illusion of gravity. If so then only thing I can visualize [from my basic understanding :) ]is rotation of earth around sun causing centrifuge as possible explanation for radially "upwardness", but that would mean if no rotation, no gravity and that would be totally miss-interpretation (as newton's law of gravitation will still be applicable in no rotation case), I know something is missing in my understanding, please help to clarify.
2. At the end of video domination of time curvature is discussed "around" earth's surface along with inability of human beings to feel 4d space time
experience. So, if time is flowing at different rate along surface of earth, then any 3d object will always have a small difference in flow of time across it's edges which will contribute to its 4d trajectory and thereby it's free fall.
-->If this understanding is correct, will it be possible for you to give an idea on how that 4d path will look like, for stone thrown upwards decelerating and stopping
after some time (v=0) then falling down (in terms of math or something... would be helpful); As in 3d it will be straight line path for stone ?
-->If hypothetical particle is considered which has distance between edges zero i.e. no reason to cause time gradient across any dimension then is it correct to deduce that
particle won't feel gravity?
Talks too fast
Go to settings and set the speed at .75 or .50. You're welcome
genius
Or x2
Brilliant. 7:25. The explanation for why spacetime curves, logically explains why our universe is operating on a matrix algorithm, where "more densely concentrated events" emit more complex outcomes, whether energy or electricity, for those who debate that.
Curved spacetime reminds me of a wonderful little poem by my favorite poet, Shel Silverstein, that perfectly illustrates this oddity:
I thought that I had curly hair
Until I shaved my head, instead,
I found that I had straight hair
And a very wavy head!
Conclusion: newton is an ant
Is this guy on amphetamines? What's the rush?
it might be easier to understand if he just slowed down a bit
I gained ENLIGHTENMENT! I realize that the world is much ahead than I thought.
My current (personal) 4D spacetime model is the following: Imagine a flat spacetime, reducing one dimension so that there are 2 space dimensions and one time dimension; each moment being one "slice" in a long. To make it easier later, let's say it consists of little cubes, that form a 3D grid.
Now put an object anyhwere in this spacetime, without any velocity. The next moment it will still be there, as well as the next one, and so on so you will get one very long "stick" of this object in space and time.
Now: put the object there again, let's say it's an apple, but this time put a planet nearby it. When this apple falls, you will see a parabola in 4D spacetime. If this apple truly doesn't move at all, then the "stick" of spacetime "cubes" that the apple is one has to be exactly on the same path that the apple is on. Or in other words: The spacetime is curved to the exact path that an object takes when falling to another object.
And actually it's not a ^2 parabola BTW but a ^1.5 one, but I'm too tired to explain that, too, right now, have to go to bed. I just wanted to give you this, maybe it helps a few of you to visualize it. But as far as I know it's still long not complete, but certainly more helpful than confusing curved lines. I also only thought of this model a few weeks ago BTW