I just can't understand space-time

[Anonymous No.12107395]

I've been researching about but it doesn't make sense for me.

I feel like most of the people just repeat the lessons but don't really understand it.

Please someone explain it to me in simple words.

[Anonymous No.12107420]

>>12107395
look up 4-speed

[Anonymous No.12107423]

>>12107395
look up Four-velocity

[Anonymous No.12107430]

>>12107395
what don't you understand?
think of space as having 3 axes: x, y, and z. now think of time as another axis, upon which you can go forwards or backwards in time. you thus have a "coordinate" in both space and time, corresponding to your exact location spatially and temporally.

[Anonymous No.12107484]

>>12107430
That's wrong though.

[Anonymous No.12107486]

>>12107484
no it's not, but I'm eager to hear what you have to say on the contrary besides "that's wrong."

[Anonymous No.12107487]

https://youtu.be/gcvq1DAM-DE

[Anonymous No.12107490]

>>12107395
>Please someone explain it to me in simple words.
It's a 4-dimensional vector space.
Nothing magic about that.

[Anonymous No.12107863]

>>12107395
>I feel like most of the people just repeat the lessons but don't really understand it.
Correct
>Please someone explain it to me in simple words.
Einsteinian pseudoscience. Relativity provides a valid mathematical framework for some applications. Nothing more. It does not actually describe the true nature of physical reality.
>inb4 pseudointellectual retards disagree with me

[Anonymous No.12107897]

>>12107490
That's not even correct, it's a pseudo-riemannian manifold.

[Anonymous No.12107975]

>>12107395
This is perhaps not an 'easy explanation' but it is the most physical one I can give. Please ask questions-this is one of my favorite subjects to talk about.

Space and time can't be considered as separate absolute quantities, or even separated and transformed independently (in a change of frame). Instead, they mix together in a sense by the Lorentz transformations. To be clear, space-time is to refer to a distinct physical object [at least, up to how physical modeling works]. Frames of reference, for now, represent a certain perspective added onto this absolute object. Because time and space can't transform in a clear way alone from change in perspective, which should be the only thing that would be required, one needs at least combine them. Space-time is this object. Then, space and time coordinates change in a predictable way based on change of perspective, and we know then that space-time is in a sense more absolute because the Lorentz transformations depend only on space and time coordinates and nothing more.

[Anonymous No.12107977]

>>12107975
(continued)
However, if we consider gravity, there is an issue. Contrary to popular belief, special relativity can account for acceleration (see Rindler coordinates). The equivalence principle says that a free falling body acts the same as that in free space. So, if we imagine two elevators A and B opposite each other, then A and B act are inertial, and one can view in A that the earth accelerates towards it. And similar for B, and one can consider it as essentially constant acceleration. Then, for A, B and the earth accelerate the same... but that can't work since A and B both need to meet the earth, so in this sense, B must accelerate faster then B to A... There is a completely nonsensical force arising from B, so the equivalence principle and accleration isn't enough. Another thing to note is that in an elevator A free falling, a light beam should appear to go straight relative to A, but for the earth, it is a requirement of consistency to, curve... It's as if our transformation to this perspective bends the light. These two physical arguments will ultimately lead to our conclusion.

[Anonymous No.12107979]

>>12107977
(continued)
Let's make a few clarifications: a frame is generally imagined to be a kind of cartesian coordinate grid based on some basis. For instance, one can consider some x,y, and z coordinates from some certain X,Y,Z basis vectors in space. One can rotate though and obtain a new frame. For the above reasons in special relativity, one includes time in the concept of frame, where one introduces the requirement of 'time' being perpendicular to space, which is a way of saying that our frame is 'still' in our perspective.

The answer, then, is that 'global frames' don't actually make sense. If they did, our first seeming paradox would be an issue-but if they are only locally applicable, with all such frame transformations as local, it makes sense. Frames become highly local concepts, and so space-time is only locally a 4D linear space. This is certainly a departure from normal physics-in most other physics, space-time is a 4D vector space (x,y,z,t). We can't even do that anymore! Mathematically speaking, space-time is then a manifold. It should be clear that this is a model of sorts-one can consider different space-times to what purpose suits. One could in theory imagine a single space-time overall but one can't actually work with this.

[Anonymous No.12107984]

>>12107979
(continued)

Whenever one thinks of manifolds, questions of curvature often come to mind. This is where we may employ our certain argument to argue that space-time is in general curved. In this manner, A and B act as inertial by which then there is no force. Considering this, then A and B travel in a locally straight line, but they are in a curved space-time globally, so the end result is it curves. One can actually confirm this by first showing that in this scenario, the Schwarzschild space-time describes our situation (this can even be derived from Einstein's field equations or can be argued on a variety of physical means) and then showing that the geodesic equations give this. The bending of light and the corresponding Shapiro time delay, as well as the atomic clock experiments, prove to be good experimental means of verifying.

[Anonymous No.12107989]

>>12107897
You're a pseudo

[Anonymous No.12107992]

>>12107395
space - is empty
time is just created variable by peoples.
now you understand.

[Anonymous No.12107994]

>>12107897

[Anonymous No.12107996]

>>12107863
If you want to be really pedantic, science doesn't tell one the 'true nature of physical reality'. For instance, one would have thought perhaps a bit prior that the true nature of physical reality was given by classical mechanics and of continuous objects. Even with Dalton's atom, not of it's composition. It's ever changing nature absolutely undermines the idea it will ever be able to truly say about the true nature of physical reality.

In terms of physics, everything is a mathematical framework to model the world. If you've taken Electromagnetism, what IS the electric field? From a mathematical perspective, a vector field that satisfies with the magnetic field Maxwell's equations. From a physical perspective, it is that entity which causes the variety of experimental results. To say otherwise what it is is to be putting a certain absoluteness on a model that has no experimental difference, can't be tested and so would really be unscientific.

Or perhaps to put it even simpler, 'it is what it is'.

[Anonymous No.12107999]

>>12107989
learn general relativity

[Anonymous No.12108060]

>>12107897
>That's not even correct, it's a pseudo-riemannian manifold.

Locally that doesn't make a difference.

[Anonymous No.12108072]

>>12108060
brainlet. even locally it makes a huge difference, the geometry is completely different.

[Anonymous No.12108415]

>>12107486
There is no "exact location spatially and temporally". Thats a classical view that is wrong. You are wrong.

[Anonymous No.12108448]

>>12107996
thats the ethernal issue of science and philosophy, how can we prove our mind is making real assertions about the cosmos? is our mind capable to really perceive "reality"? how far can we really know? is math capable of serving us to solve this issue? but then math comes from the human mind and so we go "in circulus ad infinitum"...

one of the best answers is basically a condensation of almost all philosophy it comes from john 1.1 "in the beggining was the logos/logic...and everything was made by this logic"...
this offers 2 conclusions:
1 yes our mind is "trustworthy" , our minds can really make good assertions about the universe "ego cogito ergo sum"(Descartes 1637)

2 that we are not goin to know everything with all the details about the universe because we are not the creators of it. "verum ipsum factum" (Vico 1710) meaning that only the creator of a piece of work can know all about his own creation, a third person/observer can only aproximate or grasp aspects of it but not everything in full detail. (as it is quantum mechanics is confirming this situation)

for example if we are a simulation only the programer will know the "real reality" of his creation....in what chip we are running in, in what language is our program, what is the reason for this simulation, what is the final objetive to create it, what was the intention...

the 3 option is absolutly nothing, the universe came into being for absolutely nothing at all, it will die a "frigor mortis" , climate change doesn't matter if it really going to kill us all... but why theres a conciousness that can perceive all this? it does not make any sense at all, and this option make us go back to the above in circles for the rest of humanity...

[Anonymous No.12108457]

>>12108415
You really built up your argument this time anon

[Anonymous No.12108467]

>>12107395
you will not get it.
accept that and look for challenges accesible to your level

[Anonymous No.12108478]

>>12107395
>researching
Please use a different word

[Anonymous No.12108655]

>>12108448
This is one of the most r/Iamverysmart things I've seen. And this is coming from me the person that did the 4 post long explanation.

For one, what in the world is up with that citation, it is absolutely unnecessary and is so pseud.

Also, your interpretation of physics is way off and are rambling about completely different things. Quantum mechanics absolutely does not say this and if you think it does, cite it.

[Anonymous No.12108765]

>>12107395
Space and time are the same thing. Stop dissociating or thinking of them as separate concepts. Literally time and motion are actually the same thing.

[Anonymous No.12108812]

>>12107484
>>12107486
>>12108415
It's "right" because it's a description. Much how "the sky is blue" is a correct description.
>but what does that even mean
Nothing, because it doesn't elaborate nor confirm if what you're talking about exists.

>So does space-time exist?
As a model, "yes". In reality? No.

>>12108448
I think, therefore I am not omnipotent. I am not omnipotent therefore I will cease to be. I think, therefore I am NOT.

[Anonymous No.12108814]

>>12108765
They aren't, though. Space and time alone don't even make sense as concepts in general relativity.

[Anonymous No.12108815]

>>12108457
General relativity literally is based on the fact that there is no universal reference frame and therefor no "exact location spatially and temporally" you fucking idiot. Stop posting on the science board.

[Anonymous No.12109646]

>>12107395
There is no such thing; relativity theory is just Jewish pseudoscience. Space, defined as an absence of matter, cannot have properties such as being curved. Nor is time a dimension. The entire spacetime concept is nonsensical.

[Anonymous No.12110510]

>>12107395
That grid actually stands for flow of time in seconds per second. Lower, the lower.

[Anonymous No.12110574]

>>12110510
You know what I just realized, it would make way more sense for images like that to use a heat map kind of style of conveying the idea, I think the sinking grid is confusing to some people. It implies like the earth is sinking "down".

[Anonymous No.12111640]

>>12110574
My issue with the "sheet" method of explaining gravity/spacetime is that it's 2 dimensional, it gives normies the impression that spacetime is a flat plane.

[Anonymous No.12111711]

>>12109646
>Space, defined as an absence of matter
That's a vacuum.

>cannot have properties such as being curved. Nor is time a dimension
It would be a shame if you had to prove any of that.

[Anonymous No.12111807]

>>12108448
>quotes with names and years

[Anonymous No.12111816]

>>12111640
we're 3dimensional beings who use 3d to describe 4d, that's just how it's going to be, unless/until we manage to rewire our brains.

[Anonymous No.12111854]

>>12107395
Think of it this way: The movement, decays, etc of your atoms and the subatomic particles that compose these and the energies that compose them change differently depending on where you are in space, particularly depending on the effects of gravity at said point in space. To yourself, you'll never notice anything different: If your molecules move twice as fast, all you'll be able to detect is everything around you moves twice as slow.

The flow of time is therefore a relative thing.

Being inside a point of extreme gravity slows down your matter. Again, you'll only see everything around you move faster than you but you'll feel as though you're moving normally.

This relationship between point of space and flow of time is why it's not sufficient to use just one or the other on their own when measuring anything that's not in your immediate vicinity.

space-time

[Owner No.12112994]

Thanks for all the replies, anons. No one has convinced me.

Time is not part of nature, it's something created by the human mind.

It's ridiculous to use time in a theory. There is no space-time, just space.

[Anonymous No.12113002]

Its a flat sheet that's 2d everywhere but that gravity bends into a 3rd dimension that we perceive but is not actually there

[Anonymous No.12113009]

>>12113002
very pop-sci brainlet take on the subject

[Owner No.12113010]

How can the universe be 4d if time is just something that exists only in our minds?

Einstein was a brainlet.

[Anonymous No.12113022]

How come anons here can't respond to SR implying eternalism?
>>12110837

[Anonymous No.12113821]

>>12112994
>It's ridiculous to use time in a theory. There is no space-time, just space.
Space is large open areas,to move around in space you have to cover distances,to move a certain distance takes time.opposite sides of the same coin.space/ time

[Anonymous No.12114298]

>>12107395
Spacetime
Space.time
Meter.seconds
There. Now you understand.

[Anonymous No.12114324]

>>12107395
Space and time are two extremes which you can travel in between. The faster you travel in space, the less you do in time and vice versa. Currently you are near the time edge; travelling very fast in time, but very little in space. If you were to travel at near light speed very little time would pass for you.
Space and time are connected this way, like the endpoints of a line.

[Anonymous No.12114326]

>>12107975
>>12107977
>>12107979
>>12107984
>blah blah easy explanation blah
tl;dr

[Anonymous No.12114336]

>>12114324
Took 5 minutes in mspaint

[Anonymous No.12114356]

>>12108415
You still have a location in spacetime, it's just that different observers use different coordinates.
What you're saying is like saying in non-relativistic physics you don't have a location in space and time because in one coordinate system you're at (1,7,0.5;0) but in another you're at (1,1,2;0), another at (0,0,0;1), etc. [here (x,y,z;t) means you're at x,y,z at time t]
Just as these vectors are related to each other by rotation, translation and speed boost symmetries, called the Galilean group, so too in relativity are spacetime coordinates related by rotation, translation and speed boost symmetries, called the Poincare group. The Poincare group acts differently on spacetime than the Galilean group, as it mixes space and time components up in a different way, but your coordinates are just as "real" in either case.

[Anonymous No.12114368]

>>12108072
Fuck off pseud: every spacetime is locally Minkowski, GR is locally Lorentz invariant. Go and look up what "locally" actually means in this context -- any GR textbook will spell it out for you. That's why you can always transform away any gravitational field -- there's always a frame of reference where there is no gravity, a state called free fall, described by normal coordinates.

[Anonymous No.12114392]

>>12114368
physicists don't know what "locally" means. what a surprise.

[Anonymous No.12114497]

https://www.youtube.com/watch?v=wrwgIjBUYVc

[Anonymous No.12114705]

>>12107863
>abstraction is pseudoscience
>implies that the "true" nature of reality can be known

Go back to your metaphysics 101 class you ape

[Anonymous No.12114712]

>>12108815
see if you can wrap your pea sized smoothbrain around this

what if I told you it was possible to discuss the idea of the coordinate system without actually having to map it to reality

[Anonymous No.12114785]

>>12114712
Then you wouldn't be talking about an "exact location in space and time".
You're not showing yourself to be intelligent.

[Anonymous No.12114924]

>>12107487
great vid. but would have liked to see this cylinder to get a better mental image(maybe this can't even be displayed, i dunno)