How does the curvature of spacetime create gravity?
ฝัง
- เผยแพร่เมื่อ 14 มิ.ย. 2024
- In 1919, Arthur Eddington led an expedition to observe a total solar eclipse, confirming that light passing near the Sun is deflected due to its gravity. This observation supported Einstein's theory of general relativity, which differs from Newton's laws by predicting that massive objects warp spacetime, affecting the path of light.
Einstein resolved a paradox wherein photons traveling different distances (AB vs. CD) near a massive object like the Sun reach their destination simultaneously. According to special relativity, light's speed is constant, so photons traveling a shorter path (CD) should take less time. However, in general relativity, the presence of a massive object causes time to slow down, an effect called gravitational time dilation.
To visualize this, imagine spacetime as a cylinder that, when influenced by a massive object, flares into a cone. Clocks lower in the gravitational field (closer to the cone's wide base) tick slower than those higher up, explaining why time passes differently at different altitudes. This effect has been experimentally confirmed, such as with atomic clocks on airplanes running faster than those on the ground.
Gravitational time dilation can be visualized by imagining two ants, one higher (A) and one lower (B) on the cone. Both move through spacetime at the same speed, but B's clock ticks slower due to the cone's shape. Thus, B ages slower than A.
This curvature of spacetime not only affects the flow of time but also creates gravity. Objects naturally follow the curved paths in spacetime, leading them to fall towards massive bodies. A stationary object's path in curved spacetime slopes toward the massive body, causing it to fall, illustrating that gravity is the manifestation of curved spacetime geometry. This explains why an object falls faster as it moves closer to a massive body and why, hypothetically, an object falling infinitely would reach the speed of light due to the extreme curvature of spacetime. - วิทยาศาสตร์และเทคโนโลยี
I don't claim i fully grasped all the details, but this is the best description i heard of curved space time and how it genrrates gravity. Much, much better than the massive ball placed on thin fabric animation.
The expanding cone coordinates are more intuitive than other curved spacetime videos by far 🙏
that's not saying much. and changes the meaning of intuitive. to sort of understand.
the concensus can't be explained intuitively.
Sometimes (rarely) I'm in a mindset to understand videos like this. This one hit me in the right way at the right time. Very well done. I learned a lot. Thanks.
if you believe it. and ignore the contradictions.
@@atticuswalkercontradictions?
By far the best explanation I’ve seen! Thank you
This explanation of gravity as an effect of curved-space-time is mind blowing.
It’s old. However it’s rarely explained properly
The assumption that all photons from A/B should reach C/D at same time needs a proof. It may not.
they don't. we saw the same light from a supernova . arrive 3 different times.
@@atticuswalker Not equivalent , with the earth scenario its a single mass and photons are taking a similar path , with a supernova the light take wildly different paths
@@stoppernz229 Because spacetime curved. Floathead says the same thing as this guy.
@@atticuswalker did you?
@@wiktorchm what. see the light myself. nope. but I haven't seen the cmb either. don't doubt it's real.
"Light beams which only move through space..." I cannot get my head around this. So light doesn't move through time?
Things that sit around move more through time. Things that race around in motion move more through space. Once again moving fast saves time. : )
man been trying to wrap my head around this, but after watching this, i get it a little...
Me, too. Emphasis on LITTLE.
The thing that throws people off is this name, “curved spacetime.” Sure, when you look at a rolled up piece of paper, or a digital graphic, we see the curve. But in reality there is no curve. Space is devoid of geometry. There is nothing surrounding the earth. Its literally enpty space. Wheres the curve?
You have to remember that einsteins theory is just that, a theory. Yes it happens to align with how we perceive things to work, but it doesnt provide all the answers. Its just the best explanation we currently have. We dont understand the nature of space. Thats the issue here. When you consider this example, a rolled up piece of paper, that is one way to describe gravity. But the age old question remains unanswered, WHY does gravity exist? I believe thats something we can never know.
Einstein explained the how. The why he had absolutely no idea. No one does, and no one ever will. Thats why after watching all these gravity videos, everyone has the same response, “eh, i guess it makes sense.” It can never make total sense until we understand the fundamental nature of the universe. Unknowable unfortunately. Why are things attracted to each other? Who knows, the just are 😁
@@trenken
I read your post... Earth is surrounded by space. Einstein said there is no space or time... it's space time. You changed it to JUST space.
@@francus7227it's just space because you don't know nothing about time...
@@trenkenmaybe that’s the life cycle of matter? Create black holes basically.
Good thing you incorporated photons in this analysis. The reason photons closer to gravitational influence curve more than the upper margin proves gravitational lensing occurs because photons have properties of mass, which in my opinion requires more scientific discoveries
Great video
So much easier to think about time as rate of change. Various nomenclature in science especially quantum mechanics can make things sound more mystical than they are. The double slit experiment is a measurement problem, throwing in the word observation causes people to attribute a spiritual phenomenon.
Rate of change?
No change means no time?
@@ZubairKhan-vs8fe exactly
That’s exactly it. That’s all it is. A measure at a certain rate and it dilates when accelerated or in high gravity
Professor Francis Yu - th-cam.com/video/6S8YxnbBe-Q/w-d-xo.html
Plus th-cam.com/video/CnvOybT2WwU/w-d-xo.html
6:00 why though? Why is the object moving towards a space where time passes slower?
Best explanation yet
Can you expand just a little more and in the extreme case of going trough an event horizon where the time and space axis switch? How would you represent that in a video graphic? And by the way....excelent video!
For a particular choice of coordinates, the Schwarzschild-Droste coordinates, the temporal and radial components of the metric tensor switch algebraic sign.
Understanding the "switch" is easier than many think. It sounds brain-bending that time and space switch places, but it's really just the fact that the singularity is the ONLY future of your light cone. Because anywhere you would like to maneuver when "falling" into a black hole, you will ALWAYS (100% of cases) meet the singularity (it's just in your light cone across all possibilities). The Penrose diagram has this brain twist in it, but from a simpler point of view, it's just that. Like when it's Friday night and you are out with friends, the beer is your 100% future :D (if you drink). I like to hypothesize that all singularities are the same (like in the SAME spot), because when you have a spherical universe (like an expanding balloon and space-time is its surface), when you do this 90-degree warp (like black holes do) from the surface, eventually this warp ends in the middle of the sphere. So all black holes point to the same "space/spot/something/singularity" :) . Just food for thought.
Space-time is NOT nothing, it's something that gets curved when influenced by mass... but curved is not the best word to describe what's really happening. The best word is COMPRESSED. And to be exact, only space it's getting compressed, like a sponge. While you're moving with the same speed through compressed space, you are obviously expiercing less time.
The interesting thing is to realize the nature of the different quantum fields, their interactions and how they create the gravity (the curvature/compression) in macro space-time, while there is no such phenomena in micro scales.
I understand what you're saying about compressed. If it was compressed, explain the speed of light in compressed spacetime. Try this: The space goes somewhere. It goes into time. Time dilation. Can we balance the books using time?
Great Video🎉🎉🎉
This is good work Sir…
This is all taken from another channel @scienceclic
Well explained.
❤ Very good 👍🏼
Albert Einstein discovered that space is curved.
He opened our eyes to see that traveling to other galaxies is possible,
The problem was that we went off course to detonate bombs and kill each other, forgetting the truth about
Albert's wish was to teach us that traveling to space is possible without time delaying us to arrive instantly.
We can only travel at 5% the speed of light. At that speed a grain of dust damages the ship a lot. We ain't arriving instantly anywhere.
Nice video 🧐✌️🥳.
How much gravitational field/gravitational constant to make light bend?
The radius of curvature is c^2/g
You lost me at ^@@DrDeuteron
@@rodolfosantana9015 well if you imagine a flat earth (no, not like that) and fire a laser beam horizontally, after 186,232 miles it will fall for one second with acceleration "g", so like 16 feet, and that is following curved space time, and (switching to metric) 300 Mm long parabola curved by 5m has a radius of curvature of c^2/g = 10 Pm. (peta meters)..so about 60,000 AU...space is pretty flat around Earth, yet you can't fall 20 feet without getting hurt.
Question. In this model of spacetime it flares wider as it approaches the center of mass of the earth. But, in another model, spacetime funnels into a point towards the center of mass of something like a black hole.
No. In this model the larger diameter denotes longer time taken to cover the same unit of space. The closer to massive object the slower the time gets. Your second sentence is about spacetime, and is correct.
Well, i studied general relativity at undergraduate level and as far as i can see it is just a recipe. How can space possibly be a "fabric"? Apart from anything else, fabrics do not have intrinsic curvature, but hey, neither does space , right?
The guy on the top of the mountain is younger not older , the clock in the aeroplane runs slower not faster
I am not a physicist but have a question on this. Light travels in different velocities in different optical mediums. Are we sure there is nothing in the space? Maybe something near the earth has different density that cause light travel slower.
May I have another? please?
Definitely a good video.
Maybe centripetal force and gravity are the same thing. Since space-time is bent, a centripetal force occurs in the opposite direction. In centrifugal force, centripetal force occurs because we bend the movement of the object in flat space. Where the two are balanced, a stable orbit is formed. As a result, spacecraft in Earth's orbit balance gravity with centrifugal force, that is, centripetal acceleration. In this way, he avoids falling.
If gravity is caused by bending space-time, how about centrifugal force?
Mass existing causes space to curve around it.
Acceleration is just like gravity.
beautiful explanation and illustration.
Good jpb. Now all you need is to connect gravity to electrpmagnetism.
So does curved space cause the gravity we experience on Earth, or is it due to the Earth's mass that keeps us from flying off into space?
Your image only curves in one direction.
I suggest that the surface of a cardioid be used for modeling gravity.
A) all possible angles of descent are exposed on the surface of a cardioid.
B) because the curve is from a singularity point, to a singularity point the metric curves in all directions exactly appropriately.
That would unnecessarily complicate the visual explanation with literally 0 benefit since it adds nothing to the Physical situation. It is a terrible idea. This video does its job just fine.
So, if the affect we call gravity is purely from the curvature of spacetime - does that rule out the existence of the Graviton?
Not really
We will curve space everywhere. But what is space?
There are a few mistakes because of over simplification in this video. For example the ball falling from an infinite high tower would not reach ligthspeed. The potential energy in a gravitational field is finite! So an object with mass cannot reach the speed of light.
...little confused here. I heard dropping a steel ball from a height & a feather, they'll fall at the same speed ( in a vaccum - no air resisrance ) , and they'll reach a certain speed but won't keep accellerating infinatly towards light speed. I know I must have missed something in your example though.
Thanks to Einstein who enriched physics with various thoughts
but shouldn't the cone tighten on the side of gravity?
The speed of light is not a constant as once thought, and this has now been proved by Electrodynamic theory and by Experiments done by many independent researchers. The results clearly show that light propagates instantaneously when it is created by a source, and reduces to approximately the speed of light in the farfield, about one wavelength from the source, and never becomes equal to exactly c. This corresponds the phase speed, group speed, and information speed. Any theory assuming the speed of light is a constant, such as Special Relativity and General Relativity are wrong, and it has implications to Quantum theories as well. So this fact about the speed of light affects all of Modern Physics. Often it is stated that Relativity has been verified by so many experiments, how can it be wrong. Well no experiment can prove a theory, and can only provide evidence that a theory is correct. But one experiment can absolutely disprove a theory, and the new speed of light experiments proving the speed of light is not a constant is such a proof. So what does it mean? Well a derivation of Relativity using instantaneous nearfield light yields Galilean Relativity. This can easily seen by inserting c=infinity into the Lorentz Transform, yielding the GalileanTransform, where time is the same in all inertial frames. So a moving object observed with instantaneous nearfield light will yield no Relativistic effects, whereas by changing the frequency of the light such that farfield light is used will observe Relativistic effects. But since time and space are real and independent of the frequency of light used to measure its effects, then one must conclude the effects of Relativity are just an optical illusion.
Since General Relativity is based on Special Relativity, then it has the same problem. A better theory of Gravity is Gravitoelectromagnetism which assumes gravity can be mathematically described by 4 Maxwell equations, similar to to those of electromagnetic theory. It is well known that General Relativity reduces to Gravitoelectromagnetism for weak fields, which is all that we observe. Using this theory, analysis of an oscillating mass yields a wave equation set equal to a source term. Analysis of this equation shows that the phase speed, group speed, and information speed are instantaneous in the nearfield and reduce to the speed of light in the farfield. This theory then accounts for all the observed gravitational effects including instantaneous nearfield and the speed of light farfield. The main difference is that this theory is a field theory, and not a geometrical theory like General Relativity. Because it is a field theory, Gravity can be then be quantized as the Graviton.
Lastly it should be mentioned that this research shows that the Pilot Wave interpretation of Quantum Mechanics can no longer be criticized for requiring instantaneous interaction of the pilot wave, thereby violating Relativity. It should also be noted that nearfield electromagnetic fields can be explained by quantum mechanics using the Pilot Wave interpretation of quantum mechanics and the Heisenberg uncertainty principle (HUP), where Δx and Δp are interpreted as averages, and not the uncertainty in the values as in other interpretations of quantum mechanics. So in HUP: Δx Δp = h, where Δp=mΔv, and m is an effective mass due to momentum, thus HUP becomes: Δx Δv = h/m. In the nearfield where the field is created, Δx=0, therefore Δv=infinity. In the farfield, HUP: Δx Δp = h, where p = h/λ. HUP then becomes: Δx h/λ = h, or Δx=λ. Also in the farfield HUP becomes: λmΔv=h, thus Δv=h/(mλ). Since p=h/λ, then Δv=p/m. Also since p=mc, then Δv=c. So in summary, in the nearfield Δv=infinity, and in the farfield Δv=c, where Δv is the average velocity of the photon according to Pilot Wave theory. Consequently the Pilot wave interpretation should become the preferred interpretation of Quantum Mechanics. It should also be noted that this argument can be applied to all fields, including the graviton. Hence all fields should exhibit instantaneous nearfield and speed c farfield behavior, and this can explain the non-local effects observed in quantum entangled particles.
*TH-cam presentation of above arguments: th-cam.com/video/sePdJ7vSQvQ/w-d-xo.html
*More extensive paper for the above arguments: William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023: vixra.org/abs/2309.0145
*Electromagnetic pulse experiment paper: www.techrxiv.org/doi/full/10.36227/techrxiv.170862178.82175798/v1
Dr. William Walker - PhD in physics from ETH Zurich, 1997
Interesting, but it is a book rather than a comment.
@@walidkhier5640See my short TH-cam presentation.
Well it’s been proven and you can say otherwise but your comment and sources don’t disprove relativity. It all works very well.
If the speed of light is not a constant then Relativity can not be correct, any theory based on it is also wrong. General Relativity is not compatible with Quantum mechanics. So either one or both of the theories is wrong. The evidence I present says Relativity is the problem. Science will not advance , if the foundations of physics is not challenged.
@@mrmoose1599If the speed of light is not a constant then Relativity can not be correct, any theory based on it is also wrong. General Relativity is not compatible with Quantum mechanics. So either one or both of the theories is wrong. The evidence I present says Relativity is the problem. Science will not advance , if the foundations of physics is not challenged.
What does space-time curve relative to? The very idea makes no sense unless you postulate some non-curved, flat space-time that is NOT curved.
Isn’t there any length contraction due to the existence of massive objects? Doesn’t this factor contribute to gravity?
really..."the iron ball would reach the speed of light". as far as physics goes, objects with mass can't ever get to the speed of light.
Inside a blackhole? Speed of communication.
Issue is that if time is indeed a dimension like space then if one person or thing goes high above the earth and moving faster in time then back while the other stays on the earth moving slower in time then they cannot meet since they will always be at different time points. However, they always do. As such there is no such thing as time...what we call time is just the rate at which things in our local environment act/react/interact/etc....its not a real dimension that things can move in.
It is a real dimension like the 3 before it.
There is often an overlooked and misconception about the speed of light or c as being a constant. We've all seen the value, in high school or college, and other places, many have used it within their physics problems, etc. Yet, the overlooked issue is that when it comes to this constant which it is a constant is that this is the average velocity of light in a round trip, in other words source A to destination B and reflected back to A. This is how we measure the velocity of light. It is the average of the round trip and no matter how or where we test this, we always get back the famous constant. What we cannot do is measure the speed or velocity of light in a single direction across the span of a distance from a to b. So, in truth, we really don't know its speed in one direction compared to its return direction. What we do know is the average between the two. Look at it from this perspective: C = (distance_there/t + distance_back/t)/2 which can be simplified to: C = (d_there + d_back)/2t. Then since d_there is also equal to d_back we can write this as 2*d which then becomes C = 2d/2t which simplifies to d/t. However, the magnitude of d, is not the same as the displacement from a to b. The magnitude of d is 2 * (a to b).
In other words, the speed of light from a - b can be nearly infinite, where the trip going back b - a can be nearly zero. And this range of values can be anything in between. And no matter what the ratios are, they are proportionally changing so that their resolutions all converge to the constant C. We can not measure the speed or velocity of light in a single distance, it cannot be observed. We can only observe the average velocity of light for the entire round trip. So perhaps light coming from other stars could take nearly an infinite amount of time to get to us (not exactly infinite but definitely astronomical) yet the time for light to travel back as we gaze upon it could be nearly 0 or almost instantaneously. So, the time it takes light to travel from say the Proxima system to here could take say 4 years. Yet when we look up, we don't have to wait 4 years, we instantly see it. It could be the other way around, it might get here nearly instantly, but could take almost forever to get back. We just don't know. And you know what, it's okay that we just don't know. What we do know or can determine is the average velocity which is the constant we've been using for so long. Now can this constant deviate within different environments or circumstances? Perhaps. It could be stretched or compressed based on the environment while still staying relatively close to its mean.
We need to be careful in how we interpret the speed or velocity of light as the constant C. The average uniform velocity regardless of the distances will almost always converge to this constant. The velocity of each direction independently cannot be determined.
The local vacuum speed of light is a constant. You seem to be completely confused about the one-way speed of light, or the one-way speed of anything, which is basically a statement about being confused about relativity itself.
@@KaiVieira-jj7di No one ever has observed the speed of light in a single direction.
@@skilz8098 We measure the one-way speed of light routinely in any physics lab.
@@KaiVieira-jj7dipoor creature has lost his mind. Im bad at math and immediately smelled something wrong, very quickly into his writing.
You are correct that the value of c is derived from a measurement from A to B and bounced back from B to A to be read out and divided by two AB + BA distances. It's simply because there is no way for the observer at point B to receive a message from point A that the light is coming, before it arrives to point B, by which time the message is useless.
Your second paragraph - No. You're just presenting random thoughts as if mathematics didn't exist suddenly. Your own equation C = 2d/2t checks out for 3d/3t over a triangle, 4d/4t over square, and nd/nt over any number of equal lengths travelled divded by the same number of time frames. We've done it in the lab and we've done it space, and so far it checks out. c is constant. It's not a misconception.
Your notion that Proxima light you're looking at is not 4 years old, or that it goes faster one way and slower the other, and always mysteriously giving the same average has no merit, unless you can suggest a mechanism for it to work that way. There are Variable Speed Light (VSL) hypothesis out there, but it is not what they are stipulating.
So wouldn't this imply that time slows down near more massive bodies since they have a greater gravitational attraction.
Do people in low earth orbit have longer attention spans?
The following doesn't make sense to me: How can two people in different timeframes interact? Surely, everything that currently exists, does so in the present moment. If the implication is that the present moment, the now, doesn't exist and everybody is on their own timeline then, wouldn't that render the past and future meaningless? I'm confused.
The same way you can talk to someone of the phone who is at the opposite side of the Earth - there is a delay, because the speed of light (or the maximum speed at which the information can travel) is not infinite, but each one of you remains in your own timeframe.
And YES, you are correct - time is relative! That's the whole point of relativity! You're not confused - you've just graduated yourself to a new understanding. CONGRATULATIONS! 😄 🎆
The correct question is: why does mass curve spacetime?
What force, (force = mass x acceleration) causes the acceleration. The 'rubber sheet' model assumes the object is already moving with respect to the major mass's centre of mass. A static model requires a force to begin acceleration. And more - where does the energy come from to accelerate the object. If an object falls inside a total vacuum calorimeter, it would register heat when the object hits the end of its travel. Where did the energy come from?
time is a state variable. It is man-made, mathematical, non-physical variable, to describe the state changes of the universe. It is independent from space. The existence of universe doesn’t need time, it is our human being that needs time to describe the changes。
The state changes of universe are governed by energy not time. We use differential equations to describe energy equilibrium’s states. In differential equations, time t is a state variable only. It is mathematical equivalent replacing t with kt.
Using Fourier transform, we don’t need time. We can describe the state changes in frequency domain.
Yes
Black holes slow down time considerably because of the powerful magnetic field.
you have put together a simple explanation to complex and unintuitive phisics , a model i would hope that younger generations should be exposed much earlier , are teachers prepared ? , that is the critical question .. thanks
This is not his model. This is been published before
0:13 which light? 🤔
My Question is;- This is good for moving objects. However if an object is in a fixed position in space, relative to the earth how does it begin to accelerate? Newtons laws say there must be a force to begin the movement. What is that force?
The object is still moving "through time".
The gravitational field is not necessarily stronger at the bottom of the ocean trench, as it is highest at the Earth's surface and then gets weaker as one approaches the center of the Earth (where there is no gravitational field at all). So while clocks do go faster higher in the atmosphere, they will also go faster at the center of the Earth.
Excellent point
A clock at the surface of the Earth runs faster than a clock at the center. Not by much, the time dilation is 1.0000000003 between the core and surface.
@@fjbayt NO - the time dilation runs proportional to the Newtonian potential, which is lowest at the center of the Earth.
@@KaiVieira-jj7di You are right, my mistake, i got confused, i ll erase the comment
Wouldn’t Bob be younger since he was moving faster? I could be wrong, but I think you got it backwards. The faster you travel, the slower time goes, right?
They are "moving" at the same space unit per unit of time - the only difference is the influence of gravity. The closer to a massive object the slower the clock.
It´s very interesant, but how explain what in the center or more near to the center of the earth or any kind of mass the "Acceleration" of the gravity go Up, for example in the ecuator the acceleration of gravity are minor, that in the Poles. (You can try it with one simple Pendulum) The first kind of wach... why the acceleration get up, if the time go more slow.... (You catch the contradiction...) acceleration have time to square inside...
But why do you wrap space-time in a cylindrical shape? What physical phenomenon explains this? Some kind of periodicity?
I believe it's just a way to visualize it to help understand. It's not a literal interpretation.
The constant of light applies to light in a vacuum it does not account for material
An object falling from rest cannot achieve the speed of light unless the massive body it's falling towards has an escape velocity that is also the speed of light.
An object at rest cannot fall from rest. That puts the object in motion. No longer at rest. It cannot be slower when in motion it remains behind. It cannot go faster it will lead. Hence nothing travels faster and slower than the velocity at which light travels. Nothing is actually that which is not something. The dark and void.
What creates curvature of space-time if it is not gravity ?
I'm confused now. I thought that if light or any other object travels along the curvature, they would not "feel" any acceleration, i.e. gravitational force and their clocks would tick at the same rate, just as in an inertial frame. Only from the perspective of people on earth, the view of time ticking faster the higher you go becomes plausible. Can someone explain?
You are right. There is no force of gravity and all clocks tick away at the same rate, everywhere, and under all circumstance of motion and orientation.
There is a real effect called gravitational time dilation. Clocks in a sky scraper tick faster than those on the ground. However, you falling feel no force and your wristwatch is normal to you.
Just to follow up with my previous comment: The differences in elapsed clock time in the presence of gravity is owed to the distances along the clock world-lines (the elapsed proper time) to be different lengths owed to the background curvature.
my brain died
i blame you
Wow i never really understood gravity before
03:00 the plane gets 2 different dilations, isn't it ? xD But - nice video otherwise
Why does light moves only through time in the flat spacetime diagram wrapped in a cilinder at 3:25? Light does not travel through space only, it also travel through time, its speed is not infinite.
There is no "time" to move through, unless you mean the along the direction of some observer world-line, but you still have to choose such a world-line. That said, yes, light will move equally through the spatial and temporal coordinates of the observer, Δx=Δt.
IF you want to answer this, you need to ask why any object is moving at all, why object continue to move or having inertia.
How it is propagating thru space and why it can stand still.... try answer this simpler questions first.
You have no idea what you're talking about it's hilarious
Yes, why are objects moving. So wise.
I have actually rolled up space time- but there's nothing to show, because that wasn't done correctly
It does
This is paradoxal. How can Bob meeting Alice, if Bob in 9 a clock and if Alice in 8 a clock? Even in the same location the are not in the same dimension. Bob will always be a ghost for Alice. Like in Intersteller the movie.
no, curved spacetime is NOT the fundamental cause of gravity. it is a model that is able to represent the logic of gravity. but we don't know if spacetime is a real thing. is it useful when we model reality? yes. does it mean it exists? no. exactly relativity proved this when it turned out that gravity is NOT a force. however, in classical (Newtonian) mechanics the concept of force for gravity was extremely useful. so this should be a lesson for us to stay critical and self-reflexive, i.e. to differentiate abstract models from reality.
as regards gravity, of course it can be considered as the curvature of spacetime, but this is a too geometrical interpretation which assumes the existence of spacetime which is far from evident. in my opinion, a better definition for gravity can be derived from the generalisations of the concepts of inertia and straight line using non-Euclidian geometry (which are also geometrical concepts, of course, but the existence of inertia is more trivial than the existence of spacetime). thus gravity is nothing but the manifestation of constraint in relation to space and time, which is basically revealed in the rotation of the light cone and thus in the gradual inversion of the roles of space and time.
According to Newtons law of universal gravation any two masses atract each other. So light must have mass?
A ball falling will never reach the speed of light, it will reach terminal velocity…
1:14 c = 3* 10^8 m/s
1:32 bs \ time does not exist. There should be another way to get this. Perhaps, a more organic one.
Curving space is Naked emperor 🤣
Why should we make it cilynder?
It’s just an analogy,just like flat map of Earth, we can’t really see spacetime.
The description, between 1:05 and 2:00 makes no sense.
❤
Could you describe gravity equally well by considering it as a force acting on the momentum vector of an object?
No, the force is always zero. And in the case where a pseudo-force is used as in Newtonian gravity, it doesn't reproduce observational data.
@@KaiVieira-jj7di I agree with this, but from a slightly different perspective. I do have a background in Math, Physics and Chemistry, yet, I've always had my own intuitions about things. So regardless of what we were taught to believe as being the "de-facto" truth, I always tend to challenge everything, put it to the test.
When it comes to gravity, I do not see gravity as a force. I never have. Even the term we have come to use as why objects fall to the Earth's surface as being gravity.
Now, acceleration itself is a force. The downward acceleration towards earth is what we like to call gravity. This goes back to the notion as to what "physics" is or how it is defined. And traditionally, widely accepted is that physics is the study of motion. Within that, the concepts of forces emerged, and they have always been based on "cause" and "effect".
I have never considered gravity to be the cause of anything. I have always seen gravity as being the "effect". The downward acceleration itself has a force carrier. Yet the motion that we observe of something falling down that we like to associate it with gravity is more towards the result of it, the effect of it.
I tend to see gravity as being the result or the effect that we are able to observe after a force has been applied causing its acceleration, velocity, displacement to change. I have never considered gravity itself to be an acting force, and always perceived it as a resulting effect.
So, if gravity isn't the force or the cause what is the cause then? That's quite simple, it's the mass of the object as well as other acting forces such as temperature, pressure, buoyancy, friction, energy (potential to kinetic), etc.
I threw a ball up, it's mass and density are greater than that of the air and after some amount of time, displacement, the air pressure through friction and other forces decreases the ball's upward velocity and momentum to the point where the mass of the ball and its density being greater than the air, begins to reverse its direction or trajectory. At this point, its velocity, momentum and acceleration being to increase in the opposite direction until it reaches terminal velocity or impacts another object. The visual effect of observing the change in its direction, velocity and acceleration is what we tend to call gravity.
This is where I've always differed and challenged others to think about it. I've even challenged college professors on this, and I could see it in their eyes. They wanted to agree with me, but they were reluctant to do so and didn't. They didn't want to risk their career or job by going against the established status-quo.
Gravity is not a force. It is the resulting observation it's not the cause of anything, it is the effect we witness or observe of things being in motion.
Some might argue well what about the planets in orbit? That's quite simple, it's the same thing, the gravity we are observing is the effect of applied forces and not a force itself. The orbits, that's angular momentum, centripetal forces, tension, spiral or cyclical motion.
At the foundation of it all, the study of Motion in which that is what Physics is goes back to trying to understand cause and effect. And for me, people need to stop conflating the two.
This is a crude analogy, yet I will use it only to illustrate a point.
There are two people, Person A, and Person B. Person A punches Person B in the face. Person B ends up with a black eye. Here' Person A's actions the cause is the force of the problem. Person's B's black eye is the resulting effect. Yet, others are now going around and say that the Black Eye is a Force, a Cause, when in fact it never was to begin it. The Black Eye has always been the resulting observable effect. Person A's actions, choices were the cause all along, they are the Cause, the Force of the problem. This is exactly how I see gravity. Gravity is no different than that black eye. It doesn't cause anything because it is not a force. Gravity like that black eye, is the result or effect due to forces being applied.
I wouldn't care if I was speaking to others such as Einstein, Newton, etc. I would still argue or debate this case. Would I consider or look at their arguments, suppositions, suggestions? Sure, there is no problem there. I would look at them and consider them. Yet this is my argument. This is what I perceive. And I've had college courses in Physics, Chemistry and Math. I was at the time majoring in Electronic Engineering.
@@skilz8098 What we do in physics is measure. We measure that gravity is not a physical force. We make measurements testing Local Lorentz Invariance, Local Position Invariance, and Weak Equivalence and those measurements tell us that the gravitational field is necessarily a metric field (and so necessarily described by a curved spacetime).
If you want to come up with a viable alternative to relativity you need to develop a model that gives different predictions than relativity for a set of measurements.
@@skilz8098 oh god it’s you again. That’s why you wrote an essay. You can’t keep it simple because you don’t understand it. Gravity is a force cause my mass existing in space causing it to stretch around other. Aka curvature.
@@KaiVieira-jj7di There's a slight issue with your last statement: "we need to develop a model that gives different predictions than relativity for a set of measurements."
Many within the "scientific community" are under the impression that everything can be or is measurable.
In many cases this is true to some extent. We can measure things because we can model finite examples of them.
However, not everything that exists is finite, and with that we can never truly completely measure them.
Therefore, if every aspect or premises of our foundation of understanding or observation to acquire some kind of evidence or proof is based solely on the framework that everything has to be measurable. It's kind of a moot point.
All forms or acts of measurement regardless of the measuring system that is used, regardless of the convention or notation that is used at the end of the day is still purely 100% abstract simply due to the fact that a measurement of something in general is arbitrary.
Numbers themselves are abstractions. They are abstract concepts that convey an idea. They don't actually exist in nature itself, yet the properties of nature are in some way still governed by them.
One cannot study, perform or execute physics, chemistry, biology, etc. without the use of mathematics and numbers.
The truth of the matter is every bit of it regardless of if we're able to perceive it to be discrete and measurable, finite, or if we are able to perceive it to be continuous, analog or infinite at the end of the day it is still all just a mind game.
Yet within the field of physics itself where I'm referring to practical applied physics as opposed to theoretical physics, gravity itself irrelevant of what we were taught by some textbook is the effect that we observe do to some cause or action. Gravity itself is not the cause, it's not a force.
When we drop an object, and it begins to fall to the ground, it's not falling because of "gravity". The displacement we are seeing over discrete intervals of time in a continuous fashion is the increase and change of direction of that object's velocity and acceleration. These force vectors are related to the change in momentum Mass * Velocity which also has a direct change in its acceleration and position. There are other force vectors involved such as friction, lift and drag (fluid dynamics - properties of gases), changes in temperature, density and pressure, etc.
Gravity itself isn't the actual cause of the event. Gravity is the effect of the action that caused the event.
Compare these two expressions:
Gravity emerges as a side effect or property due to objects moving through time or motion in general.
Motion or objects moving is a result of an undetectable force such as gravity.
We have observed many times over that "gravity" is relative and that it is directly and proportionally related to mass, but it's not just the mass itself or directly. It is also the mass in conjunction with its velocity, or its momentum as well as other properties or forces such as angular momentum, angular velocity.
When I drop a bowling ball it falls due to the fact that its mass: density, temperature, etc. is much greater than that of the air around it.
When I drop or let go of a hydrogen or helium balloon, it lifts upwards. It's able generate lift that is greater than its drag and with that there's a buoyancy that is generated around the surface of the balloon due to surface area tension.
When I take a volleyball and drop it in the air, it falls to the ground. When I drop it over a body of water, it falls until it hits the surface of the water. Now depending on the ball's velocity (did it reach terminal velocity) and its overall momentum will determine how much of an impact or force it generates with the surface of the water and how deep it will drive into the water before the force (pressure) of the water pushes back and drives the volleyball back up. Eventually the volleyball (provided it didn't pop and fill with water or become crushed due to the pressure of the water) it will float to the surface and generate buoyancy.
If I do the same thing with the bowling ball, it will just sink to the bottom of the body of water.
Once again, (not you directly just people in general) completely overlook or do not listen to what my argument is, what my perspective is about and pertains to.
How does curvature of space-time create gravity? By curving space-time.
Yes
@@Slo-rydehey There's another theory that tells us the gravity is acceleration.. can you explain
Another topic of discussion without any real context. Spacetime is immaterial and can not be bended and versus spacetime can not create gravity. So spacetime is mathematical hypothetical mirage never founded or proven for century. Physics is science that follows rules - observation, theory, experiment, formula and law.
"See those ants..?? Former Indras, all."
Terrence Howard would like a word with you.
Aunt B.
It's the other way around. The effect is confused with the cause.
7:09 - I am not a physicist, but I think that is the definition of terminal velocity. "The velocity a free-falling object would reach by the time it struck the surface". It's the same velocity as would take to achieve escape (velocity). On the Earth, that is around 11.186 km/s., not C. Now, from the event horizon of a Black Hole, it would be C.
Read F. BUCKMINSTER FULLER'S book
"SYNERGETICS".... Explains everything!
Wrong question. Space without time is just compressed. Space is flat not curved like spacetime.
Age doesn’t dilate
😅😅😅well information good show you 😅
Gravitational quanta ❤in digital format❤ measure the Universe?!
Кванты гравитации (цифровым способом) измеряют Вселенную?!
Gravity is a.....gradient in time. BAM.
Gosh I hate it when people put trash on TH-cam. Space and time are both metrics and don't create anything. That is the same as saying the measurement of one meter can create life. I hate ignorant people that can not learn basic stuff.
You got it wrong. The curvature of space time is a symptom of gravity.
would it accelerate to light speed? No