How Can SPACE and TIME be part of the SAME THING?
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- čas přidán 28. 04. 2024
- Go to brilliant.org/ArvinAsh to get a 30-day free trial + the first 200 people will get 20% off their annual subscription. Be sure to check out the course called "Special Relativity" to get a deeper understanding of the concepts discussed in this video.
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REFERENCES
Visualizing 4D spacetime (Arvin Ash): • 4D Spacetime and Relat...
Minkowski spacetime calculations: tinyurl.com/2bft4pw6
What is spacetime article: tinyurl.com/23mzynkj
Paul Ehrenfest paper on more than 3 dimensions: tinyurl.com/27jma7j6
Why we are stuck with 3 dimensions: tinyurl.com/23oseuup
Sean Carroll video on spacetime: tinyurl.com/27srn5ez
CHAPTERS
0:00 The most important concept in Physics?
2:00 Defining spacetime
3:15 The math of space vs math of spacetime
7:41 Let's answer your questions
8:41 How the heck can you add time and space in the formula?
10:12 The implications of combining space and time
11:10 Why not more than 3 spatial and 1 time dimension?
13:27 How to learn spacetime more deeply
SUMMARY
What is Spacetime? Are space and time the same thing? Space was thought to be nothing, an empty void with no matter in it. In 1908, Hermann Minkowski postulated that time could be thought of as a 4th dimension along with the three dimensions of space. Einstein later showed that this spacetime is a kind of geometry that can bend, affecting the trajectory and passage of time for objects. How can space and time be part of the same canvas? Space is measured in meters, while time is measured in seconds. How are the two interchangeable?
The definition of spacetime is the set of points in space and time, located with 4 numbers. This would be the location in 3 dimensional space and a time. You can also call these events.
In ordinary Euclidean space, the distance between two point A and B is fairly simple to figure out. The straight line between them is the shortest path. And it’s obvious also that any other path, from A to B will be longer.
If we change one of the coordinates to time, the math that we need is not based on Euclidean geometry, but Minkowskian geometry (or Minkowski Geometry). The straight line between A and B does not represent distance but time elapsed between two events. A straight line represents traveling at a constant velocity between the two events, and is the MAXIMUM duration. So for example, in spacetime, if you took a curved path from event A to event B, or a zig zag path, then the elapsed time would be lower compared to the straight line between A and B, because you will have traveled more in space than in time.
Einstein showed that there is no such thing as absolute time, and so that’s why we have a new formulation. But how do you add time and distance together, since the units are completely different? The key is that there in important conversion factor between time and space, that allows us to convert one to the other. And that conversion factor is, the maximum speed limit of the universe, that is, as far as we know, is the speed of light. The speed of light is the key to uniting space and time. We call this maximum speed “c” in physics.
And c is 299,792,458 meters per second. As you know speed is distance over time. If we multiply this speed by time, we get a distance. So now we can convert time in the same equation to distance - distance = c*t. Thus, the equation works by using this conversion factor.
This formulation for a 2 dimensional spacetime can be extended to the real 4 dimensional spacetime we live in. And that 4 dimensional geometry is the foundation for understanding General Relativity, with the addition that this spacetime is no longer flat, but can curve and contort. So the math gets complicated in General Relativity. The consequence of a curving spacetime is that this results in gravity.
Why do we have only 3 dimensions, why not more? And why not more than one time dimension? First, large spatial dimensions probably don’t exist because we would have detected them if they did. And more than one dimension of time could result in closed time-like loops, in other words it would allow travel to the past. This is considered an impossibility because it would break causality.
More than 3 spatial dimensions would also likely have fatal consequences. In 1920 Paul Ehrenfest showed that our orbit around the sun would be impossible if we had an additional spatial dimension. Other problems have also been identified, for example the orbit of the electron in atoms would become unstable.
#spacetime
If we had fewer spatial dimensions, then spacetime would be too simple for life. For example if we had only one spatial dimension, then orbits could not form. Two dimension would also probably be too simple to result in life. - Věda a technologie
Space and time are relative, the more time I spend with my relatives the more space I need
In fact, the ratio is inverse. Wrong.
That is precisely an inverse ratio.@@richardparker1338
"Actually" kid in the comments. It's a joke, let it be.
@@hooked4215It's a joke. Stop.
I have stopped a long time ago but you have kept moving so you think that I am the moving one.@@ashhole03
My favorite concept which I read way back when I was in Junior High school is that "when you travel at any speed you trade space for time." You gain time (time dilation) and you lose space (length contraction).
Continuous acceleration 🤔, as it makes no sense if the graph is constant
Good explanation. In my opinion, space does not contract, but rather the travelling object simply viisits less places the faster it goes. If it had to visit all places between the start and end it would have to visit anifinite number of them (because you can always sub divide between two points), which would take forever. Zenos paradox about the movement of an arrow first highlighted the infinite number of points between any two places. Modern maths makes a pathetic attempt, by inventing the concept of limits (where the crux phrase is 'at infinity', which of course can't happen), to show movement is possible if you draw a line of ink on paper, the ink will not be contigous, and the faster you draw the line, the less places the ink will mark the paper. I think it's the same for spacetime. The faster you go, the less places iyou 'visit. It works the other way too. The faster you go the less points of time you vist, so it seems time contracts. Time dialation is (in my opinion) when points in time are skipped over just like the points in space. 🙂
@nswanberg replying to whom? Please mention
@nswanberg not moving at all isn't the slowest you can go in space, correct? Extreme curvature of the space you're not moving in also plays a role in how "still" you are to outside observers. I propose you are more still relative to the rest of the universe while you are falling into a black hole, despite the presumption that falling is moving. It isn't in this case -- let me explain. When you swap space and time coordinates is when you're most still in my opinion, as falling towards and reaching the singularity is as inevitable as "falling" into the future in any given moment. So movement towards the singularity in a black hole isn't through 3 dimensional space, but through 1 dimensional time. The singularity IS your future, and there's no way to avoid it. You can move out of its way no more than you can move back in time.
So I would say the singularity is the slowest you could move, but what do I know
@@RedNomster Good stuff! Also, the more still an object is it seems, the cooler it is. The cooler something is the less engery it has. So perhaps black holes are the coldest places in the unviverse, with the least energy? Just outside the event horizon then (too adhere to the conservation of energy), there should be all the engery of the particles that pass across it, and hence this would be very 'hot'?
No one can make me understand, or believe to understand, complex physics like Arvin.
came here to say the same thing
He is dumb. There's no "time". "Time" is not involved in reality, in any shape or form.
No one can make me understand, or believe to understand, complex physics.
I really should stick to funny cats videos, and drain unblocking.
@@FIFIEGUK1975 Hilarious.
Thanks for the laugh.
This isn’t complex it’s just nonsense
Wow, I just happened to come across this video and I found the explaination super helpful with such a complex concept (you can tell that I'm not a science major here). The use of interactive graphics really helps guide the viewers to have a better understanding of the talk. But the real genius is how Mr. Arnold breaks the concept down and use simple languages to clarify the complexities of space-time (I'm still not there yet but may be I will someday). STEM students can truly benefit from this type of education. I'll definitely keep following this and hope my granddaughter will benefit from this someday, should she chooses to go into science/engineering. Thank you.
That’s a lot of difficult key concepts packed into one easier to understand video, bravo! 👏
What a brilliant video!!! you answered some of my most fundamental questions. Thank you.
Dear Arvin sir, you have simplified complex topic to a great extent. Love you.
Eagerly awaiting for your the simplest explanations for very difficult problems.❤
Thank you very much for your professional insight and helpful advice.
Hello Arvin. You should be made the education minister for the whole world owing to your exceptional pedagogic skills. Schools in general tend to repress creative questions from children. Someone like you would reverse that and then we will not just be finding new answers, but we will also be finding new questions, both of which are paramount for scientific progress.
Excellent video as always. I especially liked you putting a very obvious question 'how can two quantities with different dimensions be equated'. One question: In the video you mentioned that multi dimensional time would allow time loops to exist. How is it then that we humans are trying to invent a time machine in a space-time which has only one dimension for time? Shouldn't it be outrageously impossible?
Yep time travel is impossible just like bending space is impossible
@@chrisstevens-xq2vb what do you think about the proposed alcubierre drive?
@@shethtejas104 Funny asf. You can’t bend space.
@@chrisstevens-xq2vb Ok chill. I was just asking your thoughts on it. Relax.
@@shethtejas104 it’s called being direct….
The bigger question revolves around whether spacetime, the foundation of our current physics models, can still be considered the fundamental layer of reality, or if it instead originates from a more foundational underlying structure. While our current models have thrived on the spacetime framework, recent challenges and breakdowns in certain areas have prompted us to question whether spacetime alone can continue to provide a comprehensive explanation.
That's why so many physicists have spent their lives trying to formulate one equation for the entire universe. Einstein has been the closest with E=mc2. But that only says energy must have mass and vice versa. It doesn't account for time, which is relative to the observer. So easy to understand yet so hard to grasp until you grasp it.
I’m wondering if, and how, fields play into this structure? As he has demonstrated in other videos, space is made up of fields, like the Higgs field, and other boson fields. Is there any connection between these fields and the 4 dimensions that our universe appears to have? Matter cannot exist without these fields, so, can we have three dimensions without these fields? I’m not even sure I’m asking the right question.
@@alphagt62 > Is there any connection between these fields and the 4 dimensions that our universe appears to have?
Yes, they're deeply connected. The fields that we describe in the Standard Model only work in 4 dimensions. (Of course you can create fields in other numbers of dimensions, but they would not be the fields of the Standard Model. They would be something completely different.)
> Matter cannot exist without these fields
Matter _as we know it._ That's a very important caveat to always keep in mind when we're discussing these kind of philosophical topics that we can't prove (or disprove) using any known science.
> can we have three dimensions without these fields?
Fields are a mathematical model we humans use to describe what we've learned about reality, but they don't define reality. Reality just is what it is. It existed long before we invented the concept of "fields" and it will continue to exist long after we and our knowledge of fields has gone extinct.
> I’m not even sure I’m asking the right question
You are, you're just asking it in the wrong frame of mind. You need to dissociate what the universe is from how we mere mortals understand the universe (and that's not particularly easy - don't feel bad about it!)
One thing to always remember is that these questions cannot be answered (at least not without a view of the universe from outside the universe, which we're unlikely to ever get). They're philosophical questions rather than scientific, and they're questions philosophers have been struggling with for as long as humanity has existed. Each era within the framework of their own knowledge of course - the ancient Greeks for example pondered their "celestial spheres" rather than our current conceptualization of fields within the Standard Model - but the underlying questions are essentially the same.
Anyway that's enough rambling from me. I'll say you're off to a good start! Happy philosophizing! :D
@@alphagt62so the fields actually are space time. The 3 physical dimensions are just those fields all stacked on one another and that forms the “fabric” of reality
Considering the longstanding emphasis on spacetime as the foundation of reality, it's worth pondering if we've got it reversed. What if consciousness is the true fundamental layer, from which spacetime and all its intricacies emerge? Challenges in our current models might be pointing us towards such a profound paradigm shift. There are many scientists now seriously considering this. Look up Prof. Donald Hoffman and his work on this.
I think the oddest, weirdest, and most significant science discovery was by Maxwell. His differential equations showed the speed of light was constant to all observers. That's told us that the universe was one weird place.
This is such an amazing encapsulation of a difficult topic. I could have skipped dozens of videos by simply starting here!
So how does space bend?🤣
@chrisstevens-xq2vb
Over backwards.😉
@@leeg8461 People actually believe nothing can bend🤦🏼♂️
@@chrisstevens-xq2vb space isnt ''nothing''
Joy of learning. Thank you much so dear Arvin.
I love your commentary; it's so concise and ultra clear. Those two things really help me to grasp these complex ideas.
❤indeed
absolute amazing video im 35 yrs old and always was wondering about space time since school no one explained it better than this video.
Time adjusts itself for each person to make sure light speed is the same for each person/observer ( whatever that is). Crazy
Well I guess that’s to say time is relative to the perspective of each person because it’s limited by the speed of light? So somebody in another galaxy is existing in our future, but at the same time from their perspective we are existing in their future…I need to watch the video again 🧐
Einstein's relativity didn't prove that time is relative. Relative time is only a principle in it.
It's because of inertia. Moving at a constant velocity is exactly the same as standing still. Everyone and everything is standing still with respect to itself, and so relative to itself, it emits light at the speed of light.
@@smlanka4u you are right. There have been, however, experiments that proved it.
@@gaopinghu7332, High-energy muons decay slowly because they are not similar to the low-energy muons. It doesn't mean that speed changes the time. Also, photons experience time even if they don't decay faster, and their wavelenth increases with time. Planck time is not relative.
I love that you casually gave one of the most intuitive explanations for the twin paradox as an aside for your main subject matter. Your talent and hard work as an educator is so incredibly rare. Thank you.
The video did not cover the twin paradox. It only showed what observer A would see about observer B time. It did not show what observer B would see of observer A time. So it did not show the paradox, that from observer A perspective B time is slower and from observer B perspective A time is slower.
@@yziib3578 it showed that whomever travels in space and returns to that point is younger. How does this not show the twin paradox?
if we consider time as a part of space, then how can the speed of light be the same everywhere if they say that time is relative, then the speed of light should be relative and not defined constant, or if space itself is expanding with acceleration, it is obvious to me that all ideas about the world are flawed
@@Va1demar This is literally the very first thing covered by every single explanation of Special Relativity. Admittedly, some of the explanations suck, but to summarize... actually, I'm just going to go to bed, there are dozens of good videos about this on CZcams that you can watch, here, for free.
@@yziib3578 Both observers agree with each other about the spacetime interval each traveled. If one twin only travels on one side of the triangle, then the other twin *must* travel along the two other sides of the triangle. Spacetime intervals are invariant. Two sides of a triangle are always longer than the third side.
Do the Twin (so-called) "Paradox" with triplets or quadruplets and it should make more sense.
It's one of the best videos on the subject.
Thx for making it easy for us to understand it.
This is EXCELLENT! I have tried to come to terms with spacetime for ages, but Arvin has shed light where no-one else has been able to. Thank you!
As a ML engineer who works with multidimensional tensors all the time , this felt surprisingly easy
I just stumbled upon your channel and I am blown away by your relatively indepth review
You made this complex concept super easy & understandable 👍
Scientists now believe that empty space is actually filled with Quantum or Vacuum Fluctuations. _"Vacuum fluctuations appear as virtual (i.e. non-material) particles, which are always created in particle-antiparticle pairs. Since they are created spontaneously without a source of energy, vacuum fluctuations and virtual particles are said to violate the conservation of energy. This is theoretically allowable because the particles annihilate each other within a time limit determined by the uncertainty principle so _*_they are not directly observable._*_ "_ (Source: Wikipedia) Despite its name, Virtual “Particles" are *immaterial.*
I've been wondering if divisional algebras which work only in 1, 2, 4, and 8 dimensions has something to do with space time. Also I read something, not sure where, that in hyperbolic geometry that what might be time dimensions have to be smaller in number than space dimensions, that the smallest number of dimensions which works is 4 dimensions. And perhaps why space-time is 3 dimensions of space and 1 dimension of time. Now that might be just the geometry of space-time. But does that still tell us what space-time IS? What it's made out of?
there is NON-EUCLIDIAN GEOMETRY math which answers alot of your questions, also N-DIMENSIONAL GEOMETRY both are upper division class math 700s
0:08: 🌌 The concept of space-time is essential for the existence of the universe and all physical phenomena.
2:54: 🌐 The concept of combining space and time into a 4-dimensional continuum called spacetime is not intuitive, but can be understood by comparing it to the geometry of space.
5:31: ⏳ Time and space have an inverse relationship, as shown by the equation E^2 = t^2 - x^2.
8:21: ⏳ The concept of time and its relationship with space explained, including the conversion between the two using the speed of light.
11:09: 🌌 The existence of 3 spatial dimensions and 1 temporal dimension is crucial for the existence of life and to avoid paradoxes.
13:53: 📚 Brilliant offers a practical course on Special Relativity with interactive learning tools and monthly new content.
Recap by Tammy AI
Wow that yellow box @13:10 could be an idea for a whole video to attempt for us to grasp the concept alone.
Great video! I find it helpful to think speed is converted from time. We are all moving through time at the speed of light. You hinted at the conversion factor… borrowing just a little time and can give you a lot of extra speed
Gravity is constant acceleration so we need speed to overcome that and appear stationary. So we convert some of our time to speed so our time goes a little slower.
No constant speed can "overcome" non-zero acceleration, this part doesn't check out. To compensate for acceleration and appear stationary you need another acceleration, i.e. changing speed, but it would mean changing time dilation.
Nor are we all travelling at light speed lol
@ExistenceUniversity yes we are all traveling at the speed of light. Sorry, but you are wrong. Here is the proof:
czcams.com/video/au0QJYISe4c/video.html
From science clic English.
@@Name-js5uq Science clic is wrong. If you were traveling at the speed of light then you'd have no experience of time or space. You wouldn't exist as you do.
In fact you can find my 2 year old debunking of his video in that comment section lol
The short answer is our world is perfect and balanced in any terms,
Really great video! There were moments where I felt like I might actually be able to understand some of iat a novice level. Maybe watch a 10 or 20 more times. Not being cheeky here… I’ve been banging my head against this wall for years, just a really hard concept to a simile. May just have to check out that brilliant course.
you can do it!
Arvin, you are the best. And all the followers who post thought provoking comments are super best. 👍
Great video. Thank you arvin. 👍
On one hand, this is the closest I've ever come to grasping the concept, so bravo for Arvin. On the other hand, if C is distance/time, then C squared would be distance squared over time squared. Well, I know what a distance squared is (three inches on the sides of a square yields nine square inches), but I can't grasp the meaning of a time squared. What's a square second? This continues to flummox me.
Still, it's the clearest demonstration of the concept I've seen so far, and my livelihood doesn't depend on my understanding it, so I'm satisfied for today.
Maybe this won't help you, but a squared second would be something we cannot intuitively understand, as we don't have the practical experience. Said otherwise, in the practical sense, it has no meaning. Like a meter to the fourth, we don't have the practical experience. What we can do is process it analytically, and maybe it's easier to figure out what a fourth dimension of space might be as we already deal with three of them. Other than that, a fourth dimension of space has no practical meaning.
Another possible way of looking at it, although again it may not be helpful at all, is to consider acceleration. If velocity is the rate of change of distance per time unit (second) and acceleration is the rate of change of velocity per time unit, then acceleration would be the rate of change of distance per time unit squared (squared second).
Or, maybe more properly said, the rate of change, per time unit, of the rate of change, per time unit, of the distance. The analytical meaning(?) here would be that we had to consider twice independent variations in time.
Good explanation. The acceleration example was what occurred to me as well: change in velocity per change in time or change in distance per second per second. Like the gravitational acceleration at MSL on earth, 9.8 m/s^2 for a free falling mass in a vacuum.
Another gorgeous and informative video, Arvin, thank you! It is my understanding that the vector cross product, which is key to maxwell's equations, does not work in 4 or more spatial dimensions. No one ever seems to bring this up as an explanation for why we experience 3 dimensions. It's this a valid argument as to why, or is there an out for higher dimensions for electromagnetism?
there are 3 and only 3 spatial dimensions, time is not a spatial dimension, "spacetime" is nonsense.
@@axeman2638 "Spacetime" does not imply that time is a spatial dimension. In fact it explicitly states otherwise, as they have opposite signs in the equations. You can kind of interpret that as stating time is an "imaginary" spatial dimension, but its certainly not stating that "time is a spatial dimension" in any meaningful way. It might behoove you to try understanding concepts before arbitrarily calling them nonsense.
> No one ever seems to bring this up as an explanation for why we experience 3 dimensions
Because we don't control the universe. If the universe had chosen to give us 4 spatial dimensions, certainly Maxwell's equations would be meaningless. But intelligent beings in such a universe would simply come up with some other equations that describe their own forces (electromagnetism as we understand it wouldn't exist, but some other force that follows 4D-enabled rules would exist in its place).
Of course that's all speculative philosophy. The universe does have three dimensions and our equations do work, so its little more than a thought experiment to imagine higher dimension universes. But the first step to such an exercise is realizing that _everything_ we know would be different - the particles, the forces, and the math we use to describe them. Everything The ones we know of in our 3+1 universe all explicitly require a 3+1 universe and wouldn't work in any other universe. But some other completely different particles and forces (and math) might.
People have of course tried to formulate such things, with middling success. There's a general thought that its not possible because we can't make the math work but that in itself is exactly the problem I'm pointing out - just because _we_ can't do it doesn't mean the universe couldn't have. But its very hard for us to separate the idea of a universe that can't exist (based on the fact that it doesn't) from a universe that "can't" exist (based us fallible humans being unable to figure out how to make our equally human mathematics work for it).
@altrag yeah you can stick your condescending smug face where the sun don't shine mate. I know the official story pretty well thanks, perhaps even better than you, it's rubbish, Space does not warp, it has no substance or properties, it's no more or less than the distance between things, it's flat and euclidean. Einstein is bunk.
Equations are not reality.
This video was very informative and explained so well. Thanks for sharing
You are so smart.
I’m an Electrical Engineering Technician and fully understand what time is now.
Great Video and excellent special effects. 🤗
Subscribed ✔️
Thanks for watching!
It would interesting to understand the notion of spacetime from a LQG perspective or a quantized fields approach, for example the notion of "points in spacetime" would be replaced by what? Traditional Minkowsky spacetime would have any meaning at all in LQG? Or it would it be replaced by a spinfoam where the traditional notion of points in space would cease to have any meaning at all?
Does space*time have the same tension and compression resistant force? Does it have a quantitative force in it at neutral rest?
Nobody has constructed the definition of time, therefore we cannot apply ''time'' to physical bodies and using this enigmatic a ''time'' is an erroneous approach to explanation in this video. Clocks do not measure ''time''. I repeat; a clock is not a mechanism to measure time at all. Clocks do not measure anything; there is no sentient contraption in the World that measures ''time'' or feels ''time''. Therefore, by squaring '''time'' or bringing it to any power is meaningless. Space on the other hand has a physical meaning and by marrying space with time we are making a mistake by combining a ''body'' with emptiness. Time, as we know it, is not measurable but rather experienced psychologically. But I believe that we can find it ''somewhere'' externally where mind and time meet half-way. And even by relating time in terms of psychology, time cannot be explained in conveying words of what it is and when somethig was, is or will be. Until we define time the usage of this ''entity' as a dimension is wrong because time may have constituents or have a force by not being a force itself which makes it static. Time is static entropy is not.
Thank you, Dr. Ash...I kind of get it now! The causality example was REALLY helpful...
Thank you very much I really glad to watch this video it is fantastic
Back in ancient Greece, the big things were Earth, Air, Fire, Water. To me, these should be changed to Space, Time, Matter and Energy, with the first two and second two interchangeable with one another. It's a really interesting topic to me, so I'll be back to watch more of these videos, for sure! Thanks.
Consider adding "pattern," that is the relationships (relative arrangements) that are, per Arvin, played out by matter / energy on the stage of spacetime. A warning though, "pattern" is meta-physical and requires adding the dimension of consciousness. 😀
Matter and and energy are distinguished by one property: Spin.
So we should say spacetime/and spin/charge
Matter is energy.
But they were thought of as the elements which make up all matter. They have been updated. To the periodic table
No, they were earth, wind and fire.
When we speak of _space curviture_ it seems to me that this implies higher dimensionalty. That is, how can you curve something if you don't have at least one extra dimension to curve it in? One of the seminal books I grew up with was Flatland. Which explored a people constrained to a 2D plane. That plane may very well be curved, but the Flatlanders would never know it. But we, from our 3D perspective, could plainly see that.
A space can be curve, meaning it may have curvature properties, without requiring the existence of further dimensions. However, it may eventually be simpler to describe it if one does consider further dimensions. I mean, what's so special about orthogonal straight lines but their simplicity of use by our minds?
The issue is that the concepts we use to describe reality should not be confused with reality itself. In that sense, Earth may very well be the center of the Universe, it's a possible but highly inconvenient description that would only go against the Occam's Razor Principle.
I literally have a “Space-Time” playlist … I think I’ll put this on it 😊💜💫
"Space time" is what an astronaut exclaims when he's suiting up for a space walk.
If spacetime can expand and contact, the forces contained in it could also be larger or smaller. Perhaps explaining dark matter and energy
I do wonder a little about the extra time dimensions sometimes. It seems permissable for string theorists to posit extra spatial dimensions that loop back on themselves on small scales. So why not posit extra time dimensions on very small and/or fast scales? anti particles already kinda look like they go back in time from a certain perspective. I know there is so much I'm missing in this conjecture but would appreciate what avenues to go down to understand why it wouldn't be feasible.
They probably exist on a quantum level, based on string theory. As mentioned in this video, they might be unstable on a large scale. Thus higher dimensional life forms might exist on a quantum level based on particles we haven't discovered yet. Those life forms may not exist as how we know it, they might have a different concept of existence that we yet do not understand
@@GokulRaamthelegend I wouldn't go as far as life forms. All of our current understanding of life necessitates macroscopic structures well beyond the remit of QM.
Having two time-like coordinates will make it so that energy is no longer conserved, and you will never be able to get two things to stand still (be at rest) with respect to each other. There are at least two string theories with multiple time-like dimensions, and they predict things like protons decaying into heavier neutrons and stuff. Also atoms can't form, because you can't get protons and neutrons to stick together (stand still with respect to each other).
@@juliavixen176 we already know from GR energy isn't strictly conserved. E.g. redshift photons. I mean it's still conserved as far as time translation symmetry is upheld, by Noether's theorem, but GR breaks that symmetry routinely.
Also AFAIK zero-point energy of the vacuum is still an unsolved problem and potentially linked to the negative pressure required for the spacetime expansions we currently observe.
@@juliavixen176
I mention zero point energy in response to your statement about not being to get two things to stand still w.r.t each other. As in by Heisenberg uncertainty we can't get things to stand still period! And the energy associated with this is somewhat poorly understood atm and leaves room for zany theories such as extra time dimensions. Well I guess people that know more than me can rule it out, but I'd like to be pointed to resources that tell me why.
also sorry for the somewhat unclear initial reply, I'm responding on my phone and the app doesn't let me see your comment as I reply
Wonderful explanation!!!
can the shortest line for time be intuitively visualized as a conic section swept out over a complex plane in minnkowski representations as well? where the conversion factor (or another factor im not aware of?) is the imaginary part?
i just don't know how to positivistically visualize an inverse relation that seems negative to me (the minus sign).
i don't even know how to ask this, bc i don't know what or if I'm misunderstanding important concepts in the field im inquiring about, which is a problem i had in school too....
A lot on how spacetime works but what is the ontology of spacetime itself?
Obviously it's grounded in consciousness, which is grounded in God, the global identity of reality. 😂
I've been having to make various appointments recently, and the point is when you make an appointment, you need four pieces of information: the cross streets, the floor number and the time. So, they must be part of the same thing.
lol the variables of an event, excellent.
first time in my life really understanding space time , thank you😊
Nicely explained
Your Minkowski graph of the math of spacetime is a powerful teaching tool. I wonder if space or time can exist at all without each other. If there was no time, how could a place exist? If there was no place, would time have meaning? Are time and space inseparable? 🕳
I always thought about that. I came to the conclusion that no, they can't be separated, but at the same time, space is more important and central than Time. Time is a consequence of energy. To reach that conclusion, I used my naked imagination: Imagine you have a superpower: you can freeze everything to the quantum level. Now I want you to freeze this universe completely, until no electron can move, no virtual particle pops up in the quantum field forever. In this scenario, you'd still have space, wouldn't you? With your mind's eye, you can still see the oceans and forest and planets completely static. But time would be gone because it would literally never be capable of passing. Now, try to begin to imagine anything to conceptualize time without space. You can't even begin. You can't even think or imagine a superpower or anything. A vaccum? That's would be a space. A true vacuum? That would be space again. A black universe devoid of anything? Still a location in the grand scheme of things. So space is the basis and time is the property.
@byamboy It's this type of reasoning that makes me think Roger Penrose's idea of a cyclic universe is the most likely theory (ofc my opinion means little lol.)
When true heat death finally happens and all the blackholes evaporate, time will be meaningless. No how matter how unlikely something is, any possibility of it happening will mean it will eventually happen. Even if takes 100^1000^100000 years to happen.
Well you can think of them separately, as you can think about x or y direction in space. Space without time dimension would be just a frozen moment of the universe. Time without space would be a blank and EXTREMALY boring existence with nothing to see or touch or experience.
La elementalidad de las ideas de tiempo y espacio, nos impide o dificulta hablar de ellos. No se pueden definir sin caer en redundancias o círculos viciosos. Así, el tiempo es el intervalo que transcurre entre dos eventos. Espacio es el ámbito que habitamos. Propongo un nuevo término designar tres cosas fundamentales, que no tienen definición, es el término EXTENSIÓN, para esas tres magnitudes fundamentales, o magnitudes dimensionales fundamentales, ya que de la EXTENSIÓN, se derivan, el espacio, el tiempo y la masa. Que son tres cosas extensas. Porque pueden existir en el Universo y podemos referirnos a ellas como existentes. Porque los podemos estudiar porque muestran propiedades diferenciables, de una con respecto de las otras. Porque las podemos medir usando instrumentos diferentes. Porque acceden, de alguna manera a ser percibidas. Porque podemos cuantificarlas y los cálculos.que hacemos son congruentes. Pero que nos intrigan cuando tratamos de verlas individualmente; es decir, darles calidad absoluta de existencia. Porque, aunque no se haya dicho, la masa también es relativa al espacio y al tiempo, ya que incrementa con la velocidad o energía cinética. Incluso, se origina de la velocidad misma, se genera a partir de bosones que corren a la velocidad de la luz. Entonces la EXTENSIÓN, puede asumir el papel arquetípico o primordial, con respecto de esas tres modalidades de entes diferenciados pero relativísticamente asociados.
@@byamboy I can easily imagine a black universe devoided of anything, but I can still suspect there is some kind of time, since even this dark universe devoid of nothing, is something. So Space is the bases and time follows as a property.
The beauty of Arvin Ash's video is that after watching it for just a few minutes, I immerse myself in the experience, likening myself to a subatomic particle, and attempt to truly grasp what Arvin is conveying, and that's why it takes a couple of hours to watch the full video.
yess!
This guy made me love physics again!
I'd like to point out that Modelling Causality as a Poisson Process (events on a time line w/ exponentially distributed inter arrival times) we are transforming from the Bayesian into an exponential form of causality (np=t*lambda), e^mean*variance and plotting 'open point' on the timeline allows for a least Paths solution to A QM Model of Causality I refer to as the 'Temple Model of the QM of Causality'. The open point on the timeline represents the 'Temple' State Space Model itself. It allows the 'user' to apply the same exponential transform to the 'other parts' of the model. We can manipulate causality even w/ a pair of dice.
If space is expanding faster than light can travel through it and matter cannot travel faster than light, would this mean that if there are objects traveling toward us originating from outside our visible space time envelope, those objects would never be seen?
Yes.
Worse, it means there are objects within our visible space time envelope that will eventually disappear from our sight. At some point in the far, far, far distant future our galaxy will be left alone in the universe.
(Though if I recall the timelines correctly, the Milky Way will have burned out its last star long before _everything_ is beyond our visible horizon so there won't be anyone around to "observe" the seemingly-empty universe. Probably. Our black hole will still be kicking so I suppose if there's a type III civilization by that time who can harness sufficient energy from that without needing stars then maybe they can witness a completely dark sky?)
Yes. That is why Einstein was wrong. He forgot the conspansion and rescaling constants.
No, they would never be seen by us.
Some physicists think it's possible that the reason gravity appears so much weaker than the other fundamental forces is because there are more than three spatial dimensions. The idea being that gravity is actually approximately as strong as the other forces, but "leaks" into the other spatial dimensions that we don't perceive with our brains and so the gravity we see in our three perceived spatial dimensions seems weak.
M theory requires 10 spatial dimensions, with 4-10 being so small we cannot perceive them (like a piece of paper looks indistinguishable from a 2-dimensional object from a distance).
Too bad gravity is not a force
Gravity does affect every other thing in space. Time doesn't exist, only space. If an atom goes back to a previous position in space, it went back in our made up time, but the quantum realm doesn't care about time.
Electrons fluctuate so fast in space, that ripples into other forces like if you swir a bucket of water, it would create momentum.
@@Rodrilechan just because QM is T symmetric - minus weak force decays, doesn’t mean “time doesn’t exist”. You have to explain the 2nd law if you want to connect QM with GR.
One of your best videos!
The explanations in this video as to why there are exactly 3 spatial dimensions and one time dimension in space/time seems to provide an argument against string theory, which requires either 11 or 26 spatial dimensions depending on symmetry considerations.
String theory theorizes dimensions that are small and curled up inside the large 3 spatial dimensions. Such dimensions could exist, but 4 or more large spatial dimensions are essentially ruled out.
If these small “extra” dimensions are curled up to smaller than the Planck length, can we ever perceive them, or are they just a mathematical construct (convenience) to allow string theory to “work”?
The (very simplistic) way I look at spacetime is that space is a computer monitor and time is the ‘refresh’ key which allows more than one thing to happen in any given point on that monitor. Imagine how much bigger the monitor would need to be if we needed a new section of it for each new window we open.
The way I visulise it (if comparing to a computer) is, 1 plank time unit = 1 CPU cycle.
simulation argument is getting waaay strong.
@@Jake-rj4dx simulation argument is really an escape clause for those that dont believe in god. Basically confirming that a superior being has created this idealistic program / universe / reality.
Your work just keeps getting better and better! You are priceless sir
Brilliant, love it!
Correct me if I’m wrong, but with the muon g-2 experiment and the probability of many different particles existing, is it probable that shows that extra dimensions exist and that they have different values so when they briefly interact in our space time universe, they can be measured with these out of the ordinary values?
Space and time are indeed relative, the more time I spend with my relatives, the more space I need
😂😂😂
xD
This joke is just old and over done.
@@ChopperChad time for a new one?
Really, I have never seen/heard an explanation less clear and comprehensible than this.
I am no novice of the subject and I always click on videos that look like it could help me understand a bit more: this was a mistake as I am a little bit confused now. I have to go elsewhere to get some understanding back.
The key is understanding 4:40 and 6:40. In space, the *shortest* route is a straight line. In time, the *quickest* route is anything but a straight line, BECAUSE, moving slows down time relative to the traveler themself. It's only misleading if you're assuming slow velocities like walking (it's mathematically still true, just a negligible difference), or more apparently, that the traveler in greater motion meets the non-moving traveler at a later time. They both meet at the same exact time, but one took a longer path through space, and motion through space slows time for that person relative to a stationary observer. The closer you are to the speed of light, the slower time passes for you, relative to a stationary observer. Light itself experiences no time, because it travels at the fastest possible velocity in the universe. This is special relativity. General relativity on the other hand paints the opposite scenario, depicting the slowest possible velocity in the universe. When falling into a blackhole, the dimensions of time and space flip. Instead of 3 dimensions of space, there is only 1, because no matter how fast you're going in any "direction" you'll always end up falling into the singularity of the black hole. It is physically the only location in 3 dimensional space you can head towards, and there's nothing you can do to stop it, which is synonymous with 1 dimensional time. AKA, the future.
@@RedNomsterSo time is slower the closer you are to the speed of light - what if you’re moving away from each other at the speed of light, would time appear stopped from each person’s perspective when looking back at the other person?
But then if you’re travelling towards each other at the speed of light you would collide at twice the speed of light, so speed is relative as well? And because you need light to see, it would be like someone killed you in your past?🧐😅
@@steveco1800 moving at light speed would require you to be massless. Like a photon (light), if you reach lightspeed, you wouldn't see anything, because you would have 0 time to experience during your travels.
But, if you're traveling very near the speed of light, according to special relativity, you experience light like ever before. Meaning a person in a car traveling near the speed of light would actually see their headlights shine and illuminate what's in front of them like ever before. Light is the same for all observers, stationary or not. It seems unintuitive, but it's experimentally proven!
It would look different, though. As you're traveling near light speed, light coming in your direction, aka the universe and objects you see would be blue shifted. The same way cosmic expansion causes redshift by expanding the space and thereby light waves traveling in space, light waves from behind you would be redshifted. It's called the doppler affect, and is the same as sirens 🚨 sounding louder as they approach, but quieter after they pass you, even if they're the same distance from you at both moments.
Faster than light speeds is when you start seeing yourself in the past and such! But that's a theoretically impossible velocity through space.
I like that you point out that 'time' on the surface of earth is slower compared to an identical clock in unaccelerated space.
However, gravity doesnt 'curve' spacetime, it pinches it in to the core of the gravity well (the earth in this case). Any 'curves' or orbits have to do with the other object's speed relative to the earth's gravity well.
Light gets bent very little as it races by our dimple of a gravity well. As a contrast, a person standing on the surface has their curved spaacetime starting at the top of their head, out their feet and running straight to the core. Our way there is blocked and that's why we feel 'weight'
The way to the center of the core is blocked because matter under acceleration stratifies by density with the heavy dense stuff at the bottom and the light atmosspheric gasses at the top.
What would have been a nice touch in the video would be to further the explanation that time is fastest in unaccelerated spacetime, it's slower on the surface of the earth with our meager 9.8m/s2 acceleration and it is most definitely slowest at the core.
assumptions of Newtonian weightlessness at the core are not considering this reality. The densest elements migrate to the core, while gasses go up. Acceleration is greatest at the core and time is slowest.
I love your science Arvin
Arvin, another great video. Thank you for the english subtitles, is a great help! I am from Italy, I can speak english but subjects like this are very complicated and sometime I miss a word (or two :-) ) and I can pause the video and read. Grazie 1000
Awesome. thank you. BTW, I also have Italian subtitles on this and most of my newer videos.
@@ArvinAsh yes I know, it's great ! But I prefer the english one, for my exercise (kind of :-) )
General relativity and quantum mechanics will never be combined until we realize that they take place at different moments in time. Because causality has a speed limit (c) every point in space where you observe it from will be the closest to the present moment. When we look out into the universe, we see the past which is made of particles (GR). When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past. GR is making measurements in the predictable past. QM is trying to make measurements of the probabilistic future.
I don't understand your second sentence, can you please elaborate?
Whats stopping you using GR to make measurements of the probabilistic future?... Nothing, your statement is wrong. I feel like you're getting hung up on the time aspect when the forces involved are at different magnitudes of strength. A tiny magnet can overcome the gravity of earth etc
A "predictable past" is an oxymoron. Maybe you mean the "observable" past? There is no such thing as "the present moment" because your present is not my present. The differences may be imperceptible but they are nevertheless measurable. Every observer has a unique world-line because of "locality" (two particles may not occupy the same space at the same time). Quantum observations are never "instantaneous" but are measurements of things that already happened.
Time and Space are an illusion humans are wasting their time by studying the observable universe,,the thing is that we cannot imagine and define things that are out of this world similar to computer AI whatever data you give to computer ,it only play and give information within that limit ,computer can give you new insight but within the range of data we provided but can not generate new ideas beyond the scope of data provided ,similarly this world is our box(data) we are only creating new information by combining the information that are within this world ,,we can not define and explain things that we have not seen before.
Nicely put, although it should be mentioned that c equivales to the speed of massless particles, not especially photons. If would happen that photons have mass, then their speed wouldn't be c.
I am so impressed my the way you explained that i hit like button and subscribed spontaneously. Hats off to you sir. You are by far better than many as i keep watching such content.
From Pakistan
Can you please make a video about the leading theories of what there was before the big bang? If there are any notable ones, that is
MgT: Yes, Please!!
As time began with the Big Bang, what's the meaning of "before" in that question?
Arvin, Magnetars would be very interesting topic to explore. BTW very nice work in this one. 👍
Just discovered your channel and I love it. If I could offer a little constructive criticism, the stock footage sometimes feels a little too "stock," if you will.
Great information. Have a good day.
Excellent video! 😊
There should be an extra dimension we call information.
Maybe “state” is a better choice than “information,” as information is limited in speed to c.
Time dilation IS the detection of an addition spatial dimension. Here is a great video about it: Chapter 1-4: Rethinking General Relativity as 5 Dimensions of Physics - A Unifying Theory of Gravity
Can you make a video on how the math on GR is interpreted so its visualised as a curved spacetime
time is movement, which is the simplest way to put it
Motion doesn't create time. Only clocks create time. ;-)
@@schmetterling4477 im not talking about clock time. clock time is just based on earths rotation. it is meaningless in space
@@noidontthinksolol There is nothing else than clock time. The rotation of Earth alone doesn't create time. Time requires the communication of the state of the clock to an external system, i.e. an energy transfer. In case of a rotating planet that's a very, very small loss of energy, which makes rotating planets reasonably good clocks.
Clocks running slow doesn't mean time is different. There is only one 'now'. Calculating a difference your clock shows doesn't show anything about time.
There cannot be “only one now” if the twin experiment has them both subjectively experience time the same yet one ages significantly faster.
@@magicmulder clocks and systems ticking ay different rates only require one now. Even on earth clocks in various places drift from one another
There is no such thing as "one now" -- the "one now" that someone on Pluto describes would be different than the "one now" you describe because Pluto is moving faster than earth. When you say, my now is "now" - what does that even mean, because there is no way for you to communicate in the very instant that you say the word "now." Even when you are talking to a person across the room, the "nows" are different for the two individuals because it takes a small amount of time for you to see the light reflecting off of them. This does not make any practical difference because the time difference is so small that you do not notice it. But on cosmological scales, this communication speed limit makes a difference in what you can possibly describe as a "now."
@@ArvinAsh Just because you can't perceive every point in space at the same moment doesn't mean it's not currently experiencing the same now as a current observer - heck you don't even get to see 'now' since it takes time to propagate through neurons...
At some point in the future you will observe its state that occurred at the time in the past that it experienced the same now as you (again not that you would see that) There's no evidence to support that there is any more than the current instant happening in the universe - observation of that is of course limited by propagation delays of that information. There's certainly nothing that has already happened tomorrow or at any time after 'now'... everything that is perceived is from a time in the past from any observers point of view, but that again doesn't mean it hasn't already had many more interactions already between the time you see it at, and the time it is at when you are seeing it.
It's actually observable... light travels about 1 foot in 1 nano second. Computer clocks tick at 1Ghz+... 1Ghz is 1 cycle per nano second... so every N feet of distance is also N nanoseconds in the past from your point of view... When dealing with a hardware device in the 90's I got to learn just how long a nanosecond is... putting the card on 6 inch extender on an ISA bus delays the signal about a nanosecond (since electric signals really only go about half the speed of light maybe more, i've seen more recent approximations that it's 70-80% of the speed of light, but given the amount of capacitance a signal has to fill before a signal can actually be detected 50% is good enough; that short distance started causing it to fail on certain motherboards. But certainly every signal that went 6 inches was perceived from a ( it's not 'now' at that point it's a past now that the signal was generated, before it is observable at a time after it was generated... but still that card is generating signals in the 'now' that will be seen later).
There's certainly no evidence that anyone is stuck in the past, any more than that events have already happened after now.
Whenever I hear that time slows down between a twin on earth verses a twin in orbit, I have to compare it to the motion of the planets. The earth is moving around the sun at a certain speed (the ground based twin's speed) but the orbiting twin would only be going faster during the forward part of his orbit. For the other half of his orbit, he would be in retrograde and undoing his speed gain assuming an equatorial orbit. So wouldn't that be a wash in terms of time differences?
Well, that's a good question.. this is my attempt xD The Earth rotates, making the twin on Earth rotate but at surface level. But the twin orbiting the Earth in space, travels a greater distance (more circumference). And if Speed is Distance/Time, and he is moving more in the same amount of time, then he has a greater speed, therefore, time runs slower from his point of view.
While it's simple to just say "large dimensions" to exclude the compact dimensions of things like string theory, it really raises the question of how spatial dimensions can come in a variety of "sizes".
"How Can SPACE and TIME be part of the SAME THING?" "SPACE and TIME" or Space-Time are *Information* within a construct which follow pre-established Universal Laws as Space-Time unfolds into existance.
Both are fictitious and both are artifacts of the mathematical nonsense of the Special and General Theories of Relativity.
Time dilation is an artifact of the mathematical errors in the Einstein derivation in his Special Theory.
Space, when represented as a real object, comes from division by zero in the General Theory.
So what is the unit of ‘E’? RHS is distance (after the conversion factor’c’) but E is said to be elapsed time.. So how does that add up?
Thanks in adv n Regards
Rahul
It's just so totally weird that anything even exists, and we're aware of it.
I don't understand why the variable "t" is replaced by distance formula (x= c*t), and not by t=x/c? :/ some one help please?
I am loving your channel! You are an excellent teacher. I really enjoyed when you said "drum roll" lol We new it was coming! I also liked how you described with the graphics the difference between newtonian time (absolute) and relative time, it's very visual.
The variable t wasn't replaced, it is still there. The constant c was added to the expression as a "conversion" factor, making the expression not only dimensionally correct, but quantitatively correct as well.
c= light speed...astronomers had much influence...looking at a distant star, its simple to say its 4 LIGHT YEARS AWAY, HARD to understand 10E19 METERS AWAY...
Before watching this video, I thought we need to consider the velocity of the object along with time and distance. So we need time as fourth dimension. But now I clearly understood how it is related and used. Thank you.
So two questions:
1. How is Fermat's principle of least time to the discussion of the time elapsed between distance traveled between two points? and 2: I can move up or down, back or forth, forward or backward, but I can only move in one direction in time. So what makes time a different dimension?
Amazing explanation!
Thanks. Well done!!
Arvin, shouldn't the negative sign come before the time coordinate in the equation, instead of before the space coordinate?
There are two alternative conventions regarding the signs, we just pick one and stick with it, it works either way.
I can't find videos about the contraction of spacetime. Recently, the confirmation of gravitational waves suggests the possibility of manipulating spacetime to adjust the speed of light in contracted or expanded spaces, something similar to creating another dimension of space within space itself. This could allow the creation of repulsive gravity or antigravity, although the creation of negative mass still seems improbable. However, it now appears possible to produce a form of negative spacetime. I suggest investigating the idea of generating gravitational waves with alternating momentums between positive and negative. By harnessing the energy of one of these momentums, virtual particles could be generated, resulting in the contraction of spacetime. Additionally, it's also possible to consider the idea of colliding a particle on the surface of a heavy material that could generate some momentum in space. I believe that waves within a heavy material propagate more slowly, which could alter the symmetry of space outside of this material.
Best explanation ever 👏🏾
I can't help but think that there may be a second time dimension (or a dimension of "probability" that is neither space nor time). Since quantum particles apparently take all routes through space, which are then averaged out to come to the main one, and particles like in the double-slit experiment interact with themselves, then since there is only one particle and time should have it in one place, it could be another dimension of time or probability that lets it go on its multiple paths. And that also makes me think that the many-worlds interpretation could be correct.
There are no quantum particles. There are only people who aren't paying attention in high school physics. ;-)
Very fine video!
Does this mean that if I move in a circle in space, then I go faster into the future than if I move forward, in a line, in any direction in space (from the point of the moving object)?
the straight line means constant speed. The longer line, means more distance in the same absolutely time (t), so more velocity. So you can go faster into the future if you move faster, but basically what you are doing is slowing time from your point of view (elapsed time).
Appreciate you, Arvin.
With every physics video I watch, I still think my spacetime cells idea has a shot. SpacetimeCells and then the normal domain name.