please tell me this shit is wrong.
>>7854859
this shit is right
I can't help but feel that's wrong. I have been told at school that the gravitational force of a star pulls the planets towards its center.
At a counterpart, the speed of the planets pulls them away from the stars grip. The result of the antagonism of both forces is an elliptical orbit, where the star is one of the centers of the ellipse.
Who's right here?
>>7854868
Both are models that describe our reality
Einstein's general theory of relativity proves that pic related is correct.
![AT_7e_Figure_02_23_L[1].jpg](https://i.imgur.com/k9xbotE.jpg "AT_7e_Figure_02_23_L[1].jpg")
>>7854868
just like this
>>7854872
I can't understand it... If we orbit the star solely because of the "bending space" where does the planet's velocity enter in the equation, if it matters at all?
We were told that if the earth would stop speeding at this moment, we would go in a straight line towards certain death meeting our home star.
This comic implies that our speed is irrelevant, because our elliptical orbits are a product of the bending space around the sun.
>>7854880
Perhaps velocity bends space aswell?
>>7854880
https://www.youtube.com/watch?v=MTY1Kje0yLg
>>7854890
Oh that's very flawed. Take a closer look at 7:40. See how the little marbles he puts on the fabric go straight to the center of gravity. He has to actually project the last marble with certain speed so it can go around in an orbit. The same with the other balls he pushes there. He throws them with an initial speed. Same concept as this >>7854873
Once again I say, the reason the planets don't go straight into the star is their velocity, not the bending of the space.
>>7854890
I don't like this explanation of gravity at all. The bowling bowl on trampoline analogy at least. It fails to demonstrate that space is being bent on all axis in every direction. It becomes much more complex at that point.
>>7854919
Except stars and objects don't have friction and can maintain their velocity.
>>7854873
>>7854880
The picture is the newtonian model of gravity. It works very well and is a good topic for kids to study.
GR is in ops post and this is how the universe actually works. There are no known discrepancies between theory and observation with gr but there are things observed that newton physics can't predict.
Have you ever thrown a coin into one of those spiral things? Orbits in gr are similar to that.
The picture is misleading because the distortion is actually 4d, not 3d
>>7854859
itt: High schoolers who think they're super smart trying to claim that GR is wrong, while being complete fucking imbeciles
The idea of gravity as a force is Newton's theory. The idea that gravity is a distortion of Spacetime is Einstein's Theory of General Relativity. We know that the theory is far more precise, and while clearly not EXACTLY correct, (until we reconcile it with quantum mechanics) it is certainly the best theory we have.
For slow moving objects in weak gravitational fields (gravity is the weakest of the forces, so planets moving around the sun definitely qualify as slow and weak), Newton's theory is a very good approximation to General Relativity - It got us to the moon and back.
>>7854859
Why is space a flat plane?
>>7854859
The shit is wrong. The sum of the gravitational forces of all the bodies in the solar system means that the centre of rotation of the entire system is not at the centre of the solar mass. And, it keeps moving position.
>>7854859
>please tell me this shit is wrong.
The bent fabric analogy is completely wrong, but it doesn't matter because you're trying to explain shit to a layman so you might as well use a flawed model.
>>7854946
gravity is not a strong force. It really really isn't.
The force coming from every object in space is negligible compared to closer larger objects like the sun.
This is the science board right? Jesus fucking christ you guys get your fucking shit together. This is some early grade school shit right here.
>>7854943
>It got us to the moon
let's not enter this topic
>>7854943
gravity is the weakest of the forces
You know that always bugged me... How come the little shit radiation, or a fucking magnet can be stronger than the massivness of a blackwhole?
>>7854953
Stop being so condescending.
Jupiter is massive enough that the center of gravity of the system is not the center of the sun, but it's still inside the sun
>>7854960
yeah son everyone knows the moon landings were faked
>>7854968
That's the point.
Two magnets are attracted/repelled by their fields and not by gravity. That's why we call it weak.
Gravity scales more than em forces on large scales however
>>7854968
Hold something in your hand. With very little effort, you've picked that up dispite an entire planet's efforts to the contrary.
The only reason it's the dominant "force" over long distances, is because it is always attractive. The earth has roughly the same number of protons as electrons, as does the sun. So the electromagnetic forces - attractive and repulsive - between them cancels out to basically nothing. On the other hand every particle contributes some gravity, so that over a large number of particles, it adds up.
Gravity is a fucking lie. How do we not get pulled into the sun if its reach is greater than a light year?
https://m.youtube.com/watch?v=S6Osm7azX6k
>>7855017
Technically it's reach is infinite but who cares how long your arms are if you're crippled
>>7854919
It's both you imbecile.
>Throw a penny into one of those coin funnels
>It orbits the center
WHOOOAAA.
It stays in its orbit because there is no friction, before you ask.
>>7854976
>Jupiter is massive enough
>>7855046
>polandball
how can the sun make distertion in something that is not even tangible
>>7855046
>talking about mass
>shows picture of volume
What is barycenter?
>>7855058
How can peoples make distribution in air when it's no even real
>>7855046
>Jupiter is massive enough that the center of gravity of the system is not the center of the sun, but it's still inside the sun
he is still correct
http://www.waykiwayki.com/2015/07/flat-earth-gravity-is-hoax.html?m=1
>>7854919
...but it's both. The velocity of an object determines if it can stay in a stable orbit, escape or spiral inward, while the "bending of space" determines how far away from the massive object any orbit for given velocities will be.
>>7854859
Any thoughts on gravitational waves being detected?
>>7854943
Is it really true that they went to the moon on Newtonian mechanics? But why? GR had been around since 1915
>>7855091
>Gravity making waves.
>gravity affecting itself
>something that is hypothetical has mass
>>7855098
To solve the differential equation
[eqn]\frac{dy}{dx}=x[/eqn]
you can 'multiply' both sides by [math]dx[/math] and integrate or you can do it using an analytic approach. In the end, both get you the answer you were looking for, so which one are you going to use for practical applications?
>inb4 not [math]\mathrm{d}x[/math]
>>7855134
I'd chuck it into a computer.
>>7854976
how can anyone have a conversation here if they have to stop to explain the most basic of shit every other post.
>>7855145
Well duh we're all high school dropouts here what did you expect on a Chinese cartons forum. Go someplace more professional
>>7855145
Because it stimulates thought right?
Most people on /sci can't write a proof to save their life or even think logically
You know shit. Einstein just modified Newton's law so it is Lorentz invariant. Even a accelerating coordinates makes a proper coordinate.
There must be some substance to be "curved". The real space is uncurvable. Now, light goes curved becouse it goes straight in this substance, but mass causes the substance to be curved and all masses follow this curved path +accelerates just lke Newton told.
>>7855098
Not far off I think. I believe they may have taken Gr into consideration to some extent, but the calculations of Newtonian Gravity are far simpler, especially on limited processing power, and can be shown to be precise enough for thier needs.
>>7854923
There's no way to demonstrate 3-dimensional spacetime is a simple visual way... The 2-dimensional trampoline method is fine and can be mentally applied to 3-dimensions for those who want to. At the very least it accurately explains the basics components of our solar system.
>Gravity is caused by a big mass on a trapoline
>Need gravity to pull the big mass down the trampoline, but there is no other sources of gravity.
This does not explain it all. Why two masses, initially at rest, pull each other in the first place?
>>7855159
>Engineers use the most expedient solution
Someone tell this to /sci/ because once I made a thread about calculating propeller thrust with Newton's 2nd law and I got called a faggot for not using FEA. Nigger I am a hobbyist with pen and paper not a university outfitted with the latest CFD software.
>>7855175
Nobody says that space is an ACTUAL trampoline that gets physically pulled down dude... It's an analogy. It clearly says mass causes a distortion in spacetime.
>>7854859
https://www.youtube.com/watch?v=srVlo1Ez5fk
>>7855187
Maybe you shouldn't do analogies if they only raise more questions and actually does not help at all and are generally wrong.
>>7854868
But where does the planet have the energy to spin around the sun from?
>>7855208
Literally, the energy came from the big bang
>>7855219
But then Earth would decelerate, but it revolves at constant speed
>>7854859
You better pay attention OP because I drew this for you. My example A is in your pic. The example B is what actually happens. The fabric is bent from all sorts of directions
>>7855314
Actually forgot pic
>>7855314
>>7855319
Now behold what happens when an object apporoaces the Sun. The dotted lines are potential path of the object. As it gets closer it path constantly changes
>>7855193
Science has been using that analogy for a long time now and people get it. They realize it's an analogy. You're either over-thinking it or are retarded. Do you realize that most 3-dimensional scenarios are broken down to 2 dimensions anyway?
>>7855348
I didn't...? It was imported from a drawing tablet. Besides it looks cool on 4chins.
>>7855357
You did, and it doesn't look like anything because some of us use a black theme.
>>7855368
>lel
>>7854859
The "ball on a trampoline" analogy is a decent way to visualize gravity to a degree but it is a bit misleading. You are using gravity to visualize gravity. Plus, such demonstrations don't showcase the warping of time, only space.
I recommend this video if you want a good visualization of what it means to bend spacetime.
https://m.youtube.com/watch?v=jlTVIMOix3I
I had another video similar to it somewhere but can't find it at the moment.
>>7855319
Looks like a load of dicks rubbing eachother mate.
>scalar field depiction of gravity
hello retards
>>7855192
fuck off loser
>>7854859
I still don't understand why this changes everything.
>>7855544
Dude that's harsh I worked hard(lel) on these drawings
>>7854919
The reason that that model doesn't work perfectly is because there is friction between the balls and the fabric. Space does not have this friction.
>>7855570
>what is frame-dragging
It's negligible for "small" masses like that of the earth or even sun, though.
>>7854859
What's pulling the sheet down though?
the trampoline shit is a horrible analogy
this pic shows how gravity curves spacetime
>>7854859
>distortion of the space
The pic is wrong - should be "distortion of spacetime".
- Put two masses in spacetime
- Tie space in a knot, leavie time untouched
- Nothing moves, no acceleration, no gravity whatsoever.
In GR (and SR too) all objects move forward in time in all reference frames, so distortion of spacetime will cause them to accelerate.
Its not really on plane though. Not a 2d plane anyway. I kind of assume that it is like a sphere of distortion, instead of a circle.
>>7854859
It's wrong
>>7854868
It doesn't so much pull something, as other objects want to fall into the hole it created.
However, saying that objects pull at each other isn't a terrible way of describing it at a basic level either.
It's kind of both a "both right, both wrong" approach because neither are completely accurate, but they do a good enough job at explaining the situation unless you want to be a theoretical physicist or a pedant.
>>7854859
Pretty much as accurate as such a superficial account can get. Nonzero curvature -> notion of straight line changes. Of course, the picture misses a bunch of possible geodesics, but that's really the only thing wrong with it.
>>7855770
>the trampoline shit is a horrible analogy
Not really. It's easy to understand. Heavy thing creates dip. Things fall into dip. Making go fast around the edge of dip and it curves around until it either escapes or falls into the centre, creating a bigger dip.
As far as basic examples go, it fits fine.
>>7855770
that is showing the exact same thing in 3d
A curved line would be showing it in 1d
These things are literally identical descriptions, just scaled to different dimensions. There is nothing wrong with any of them.
The marble rolling around stretched fabric description is nice because you can do it at home for kids or something.
>>7854859
It is wrong. Mainly because there are things about the dynamics of rubber sheets that the analogy doesn't take into account.
https://medium.com/the-physics-arxiv-blog/relativity-shock-experiments-reveal-that-deformed-rubber-sheet-is-not-like-spacetime-b8566ba5a110
>>7855985
You could follow your line of reasoning and say that anything that is not actually spacetime itself is wrong as a representation of spacetime
Its a model, its not ever going to be exactly accurate, its just going to be a representation that will have varying degrees of accuracy depending on how good the model is.
>>7855985
Yes, well, if you are demonstrating a model with known flaws, you explain what those known flaws are.
I mean, the obvious problem is that any balls used on rubber or a sheet will be subject to friction and won't be able to create a stable orbit.
The point is not to create a total, 100% accurate representation (you could only do that by actually simulating space-time, which if you've done I'd really like to see) it's to create a representation that is similar enough while being simple enough.
>>7855346
I'm definetly overthinking it. What exactly pulls the yellow ball down? That's right, earth. But what if there wouldn't be earth nearby? And how this tells why two masses, initially at rest, are attracted to each other?
>>7856001
IT is representing that the fabric of spacetime (represented by literal fabric here), is being warped by mass (represented by stretching due to a heavy object here), which causes things traveling in a straight line, to follow a curved path (represented by pushing something in one direction, and having it fall into the little cone here)
The only part that could possibly give any one trouble is being able to visualize it scaled up a dimension, which the 3d image posted above does. Thats basically what my mind sees when i look at the 2d example and try to imagine it in three dimensions. That 3d image is showing an effect that could also be visualized if you took the 2d examples fabric, represented it as a wireframe, and rotated it around the central object, took a picture every so many degrees, and then stacked them all into the same image.
If imaging a representation being scaled up or down a dimension was a unique problem that only came up here, maybe id be more sympathetic to the critics, but you have to visualize things that are unvisualizable in your minds eye all the time
this fits well with gravitational waves yes? they are essentially waves on the surface of the "trampoline" caused by movement on it
is gravity the "shadow" of the 4th dimension?
>>7856026
>What exactly pulls the yellow ball down?
In the image? The yellow ball is the sun. Its mass is what pulls it down some.
>what if there wouldn't be earth nearby?
I dont see the relevance. If there was nothing nearby then the sun would sit there in its little dimple and not attract anything with significant force
>And how this tells why two masses, initially at rest, are attracted to each other?
Both have gravity, and gravity extends on forever it just gets weaker and weaker over distance. So two massess on the oposite side of the universe, if there was absolutely nothing else in the entire universe at all, would slowly accelerate towards each other untill finally coliding. If they were perfectly uniform massess and there was nothing else in the universe then they would bounce off each other and then colide again untill they became one huge mass.
If they were shaped differently or other gravities were influincing them they would probably colide slightly at an angle or the recoil would be at a different vector for part of some of them and parts would begin orbiting each other for a while. But eventually they would become a single perfectly spherical object, assuming we dont put an expiration date on the material they are made up out of.
>>7856040
Gravity waves are just ripples in the fabric.
There's no 4th spatial dimension
>>7854859
Why is everyone so obsessed with gravity? Even my mum came to my house today to ask me if I heard about the gravitational waves
>>7856117
gravadar will let us blow up people with even more precise missiles, communicate through solid objectswith gravity waves as a carrier!
Think of the practical possibilities!
>>7855076
Holy fuck
>>7856196
I always liked that animation
>>7855149
>Chinese cartons
>>7855071
Jesus Christ am I drunk? This picture is way funnier than it has any right to be.
>curvature
>believing the earth is round, a sphere or spheroid.
"abyssal plains cover more than 50% of the Earth’s surface.[1][2] They are among the flattest, smoothest and least explored regions on Earth."
https://en.wikipedia.org/wiki/Abyssal_plain
"As is well known, atmospheric ducting is the explanation for certain optical mirages, and in particular the arctic illusion called "fata morgana" where distant ocean or surface ice, which is essentially flat,"
https://en.wikipedia.org/wiki/Fata_Morgana_%28mirage%29
How does the ectromagnetic force work, then?
Do concentrations of positive and negative charge bend space too, then?
>>7856260
What people think as Gravity could be seen as the electromagnetic attractive force that a dense mass of charged particles emits out on other electromagnetically charged masses of particle dense objects.
"Gravity is electromagnetism on a Flat Earth. Density will increase electromagnetism. So will heat.. pressure.. and friction.. Static interaction.. Sound..." - Thomas Jason Hannsz
>>7856266
Does anyone have an answer that's not pseudoscience?
"mass and energy bend space"
but what is "space", is there a proper definition already? is it "something" physical or is it just a mathematical construct?
I am very retarded and do not understand a single shit. Why am I here?
Sorry this has probably already been asked
So I grab some fabric, lay it out, stretch it out. Put a heavy marble in the center, it caves in. And when I slide other tiny marbles, they go to the big marble because gravity.
...But then... Why aren't we going in a straight line into the sun like the tiny marbles to the big marble?
>>7856314
You are shooting the marbles past the center, right? And watching them spiral down? Not just shooting them at the center directly?
We are. Given enough time we would spiral into the sun.
In our case the sun will die before that happens.
The effect requires much fewer revolutions in the marbles case because its being slowed down due to frictions since you are resting it on that fabric and also there's air resistance and such when its traveling.
But no orbit is stable, space just doesnt have very much resistance. apart from the effect of other things gravities, which in a system like ours where the things that would be upset by the gravity of say, jupiter, have already been upset enough to have their orbits destroyed, or minor effects of dust or whatnot causing imperceptibly small amounts of drag on the planet, we are basically not being slowed by anything.
>>7856314
because the earth is in a stable orbit around the sun whereas the marbles aren't in relation to the heavier marble
>>7856196
That's so scary to think about
>>7855134
"Multiply by dx" is just a heuristic for remembering the conclusion of the analytic method, which is already solved in general for any separable differential equation. Kind of like how you write out u, dv, du and v in integration by parts because it makes it simpler to apply than the actual statement of the theorem
Of course you can treat the dx_i as a nonzero linear form with dx=f'(t)*dt or the like and actually cancel but that takes some work to formalize and a more general integration theory.
>>7854944
The curvature of space was measured to about 1 +/- .12 (meaning it's mostly flat), they measured that using the accuracy of the pythagorean theorem with distant celestial bodies, since if space were curved, it wouldn't work.
>>7856577
Differential forms for more variables require that type of method, however for just one variable, like "dx" it works perfectly fine.
>>7856054
in the analogy there is the earth to pull down the ball, but irl, why does the warping of space time cause an initially still object to move toward the center?
>>7856468
its also bullshit.
they say the sun travels faster than the earth in orbit. why hasnt the sun crashed into the earth when the earth is in front of the suns path?
isnt it strange that there is no recorded stellar parralax yet we are spinning across the galaxy?
>>7856713
>no recorded stellar parallax
What is Barnard's Star?
>>7856583
>1 +/- .12
Fuck, you tingled my memesense for a moment there
>>7856713
>why hasnt the sun crashed into the earth when the earth is in front of the suns path?
Why do people post on a science board without understanding that motion is relative and that velocity is not acceleration?
>>7855175
>>7855963
Whether the trampoline is wrong depends on what you are using it to explain. If you are using it to explain the orbits of planets, or if you are imagining a force of gravity that moves things down the trampoline, then it is flat-out wrong. You need to use the curvature of spacetime to explain planetary orbits.
But the curvature depicted in the picture is real. A correct way to use the trampoline picture would be to imagine trying to draw a straight line on the trampoline that passes near the sun. Because the trampoline is curved, that line will end up bent toward the sun a little. This is the effect of the purely spatial part of the curvature. Usually you wouldn't notice it because the effect of the space-time part of the curvature is much greater. But for a light ray passing near the sun, which doesn't spend much time on the path, the purely spatial part of the curvature is as large as the space-time part. The result is that light rays get bent twice as much as you'd expect from a naive calculation using a=GM/r^2. This was a new prediction of general relativity.
>>7854937
>Projecting this hard
>>7856308
This is a fair question
>>7856308
I would say that it's a physical thing described with mathematics. Like basically everything in physics.
>>7855208
Planets condense from a rotating disc of dust and gas around what will become their sun. That rotational force is conserved. Its why the planets all revolve the same way around our sun. And the planets - except Neptune - all rotate in the same plane as the solar system, more or less. Neptune is thought to have suffered a major impact which knocked it over - its axis points toward the Sun, instead of parallel to the axes of the Sun and other planets.
A captured object COULD revolve the other way round. Can't recall which moon(s) show this.
And
>>7855583
F-D was detected by an earlier experiment(s?) of satellites in Earth orbit, though.
>>7856322
its means that the earth isnt round or at all what NASA shows us.
>>7856117
Because Einstein and General Relativity is still newsworthy. You haven't heard of the claimed detection of gravitational waves in the last 48 hours?
>>7854859
It's not wrong under modern physical models.
>>7856713
No crash because all the solar system bodies are travelling around the galaxy with same velocity, in that direction (so I should say 'vector'?). The velocity and orbit of each body relative to the Sun is not affected by this other vector.
It does make your head 'spin' to think about it all, I admit. Animation is correct, if massively speeded up, I imagine.
>>7857110
Is it possible to calculate how fast our solar system is moving (relative to the speed of light)?
>>7855534
>The "ball on a trampoline" analogy is a decent way to visualize gravity to a degree but it is a bit misleading.
>You are using gravity to visualize gravity
And therefor it's a fucking shit 'analogy' which should be lawfully banned.
>>7857132
>relative to the speed of light
You're not understanding relativity. If you're asking how fast our solar system rotates around the Milky Way, then yes. You can add that to the speed of the Milky Way relative to other galaxies too. Some of these speeds may approach the speed of light, depending on frame of reference.
>>7855076
>"But this theory of Gravity is not complete, the maths is super complex, and no man on earth truly understands it."
Fucking kek 10/10
>>7856713
How come if I'm in a car and throw a ball up in front of my face, it doesn't crash into me at 40 mph?
In both cases, the answer can be explained by looking at different frames of reference. In the frame of reference of the car, the ball is moving up and down vertically but not horizontally. The outside world is passing by horizontally at 40mph.
In the frame of reference of the outside world, the car AND ball are travelling at 40mph horizontally, and the ball is moving up and down vertically.
Similarly, from the frame of reference of the solar system, the Earth is moving around the Sun in an ellipse. From the frame of reference of the whole galaxy the Sun and Earth system is moving around it, with the Earth's path looking like one of those Spirographs.
>>7854859
it's wrong. it doesn't bend space. it bends the spacetime. huge difference.
Geometry is great.
>>7854859
who am i to break your heart, of course it's wrong <3
>>7855331
>transparent png
>i use tomorrow
you are fucking evil
>>7854859
Funny how this image by trying to introduce a whole new concept (space-time distortion) is entirely relying on the old concept of gravity force (sun is heavy so it pulls down the floor-carpet; planets are then prone to move towards the sun because of their higher potential energy, etc).
This kind of image is really a misleading analogy
>>7858043
so what's incorrect about that? gravity doesn't bend space like pictured but the analogy is correct
>>7858069
Why planets are heading to the sun ?
>>7858043
>>7856684
>initially still
>>7858081
Because the warped fabric alters their path.
>>7855076
>atmosflat
kekked hard
>>7858174
How ?
then why don't the orbiting planets hit the sun? surely they should if they are "falling" towards it.
>>7858197
They are also moving orthogonal to the sun. The planets keep falling towards the sun--and missing.
Look /sci/, it's called simplification. The OP image is a simple explanation for the common non-scientific person. It gives them an idea of how spacetime works without getting into long-winded details. It allows for the common person to envision the mechanics of the basic structure of the solar system (which is almost 2-dimensional anyway), and that's pretty good. Getting the idea out is a good thing, raises awareness of spacetime as a reality, and gets people thinking. If they want to learn more, they can. Nobody thinks there's a downward gravity in space. Nobody. If the image is so bad, then why is this not the common belief? It's not confusing anybody, yet you autists claim it's confusing.
>>7858204
i think i get you, what you mean is that the planets/asteroids/etc have their own impetus prior to entering orbit which keeps them from falling in a straight line to the sun.
so, hypothetically, if a planet was "spawned" out of thin air next to the sun, and it had a mass smaller than that of the sun, and it had no impetus whatsoever when it was "spawned", it would move (very slowly) in a straight line towards the sun, provided there is no other interference from other planets etc?
>>7858213
>Nobody thinks there's a downward gravity in space. Nobody.
I do.
>>7858218
thanks, i've always struggled with science/maths.
>>7858218
That's what the image should explain.
Except it doesn't, and it relies on how downward gravity works.
>>7858224
"The sun is very massive, causing a big distortion in the space around it."
I don't believe it says the sun pulls down on the cosmic trampoline due to the super-gravity of the universe.
>>7858237
Funny how you still don't want to answer :
why do the planet move towards the sun ?
I guess that you begin to understand that you actually have no answer except "muh magic distortion". You don't really get how it works, do you ?
Because this image is misleading.
>>7855770
So what is /sci/'s consensus, is this the most accurate representation?
>>7858256
As far as we know, gravity is "muh magic distortion." Please, explain why mass distorts spacetime.
>>7855555
5 5's
Anon has spoken
>>7858257
No, that picture doesn't show anything at all.
>>7854935
>There are no known discrepancies between theory and observation with gr
...and there are no known discrepancies between theory and observation with qm, but there are known discrepancies between gr and qm.
>GR is in ops post and this is how the universe actually works.
Never make this mistake:
1) this is how we make our predictions,
2) our predictions seem pretty good
3) therefore, this is how the universe actually works.
First of all, it's not the only way to make those predictions. For any predictive model, there are an unlimited number of ways to come to the same predictions.
Secondly, we have not come near testing all of its predictions with observations, even observations which we know are possible in our universe. Because gravity is a large-scale force, it's very difficult to investigate thoroughly (as, for example, the strong force, as a small-scale force, is very difficult to investigate with precision).
Thirdly: does it really make sense that this is likely to be a core truth of the universe? Why would one force arise from the warping of spacetime, while the others arise from something else?
Finally: believing you have the absolute truth on a matter kills the possibility that you will find a better explanation.
>>7855224
what the fuck would cause it to slow down? Its in space you absolute fucking tard. There is fuck all in its way and can keep moving at a constant speed forever.
>>7855224
Earth does decelerate. It only does so very slowly, and it's moving very quickly, so it seems like it's coasting at constant speed in a frictionless environment.
>>7858257
A good place to start would be >>7855534
A shortcoming with that video is that it doesn't really show curved spacetime, only curved coordinates in spacetime. The coordinates are curved (by which I mean not geodesics -- I'll get to that later) because of the curved spacetime, but you can have curved coordinates without the space or spacetime itself being curved (for example, polar coordinates).
So to cover the gap and illustrate how curved spacetime plays into this, consider this globe. Let's make an analogy where longitude is time and latitude is height. See the red path? That's a geodesic, which is what you get when you try to follow a straight path on a curved surface. From the perspective of someone moving along the surface and ignoring curvature up or down, the geodesic is straight, and the latitude lines are curved, like the coordinate lines in >>7855534. But despite the geodesic seeming straight to someone following it, because of the curved surface, the geodesic turns back towards the equator. That's analogous to why a falling object turns back towards the earth as time passes.
>>7858279
At some level, any sort of physical property or force "just is". Not saying that there's not an underlying mechanic that causes mass to distort spacetime, but the same would hold true for that mechanic. Otherwise, there would have to be underlying mechanics ad infinitum, which is probably not the case.
>>7854868
>muh feelings tell me that ...
>muh people in grade school told me that ...
Fucking pleb holy shit read a book you nigger
>>7856583
But wasn't that estimate made by observing the very early universe?
If dark energy expands space faster the more that space has already been expanded in the "Big Rip" scenario, then it sounds like if part of it expanded even the tiniest bit faster then that part would get larger and larger in relation to the rest of the universe, creating a much heavier distortion.
