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Yes, that's the false geometric interpretation of relativity, that gravity is not a force at all. Not worth bothering to talk about such a ridiculous idea that violates cause and affect.
"I don't like causality being violated, therefore I'll throw away an exceedingly well-evidenced theory" - Justa, in true myopic style.Yes, that's the false geometric interpretation of relativity, that gravity is not a force at all. Not worth bothering to talk about such a ridiculous idea that violates cause and affect.
"I don't like causality being violated, therefore I'll throw away an exceedingly well-evidenced theory" - Justa, in true myopic style.
According to relativity, warped spacetime is the cause of gravity, which means it is technically not a force (though it can be modelled as such in classical mechanics). It is a fictitious force, not unlike the centrifugal force.
To throw away all of general relativity, despite its century of confirmation after confirmation, simply because you don't like it, is to deliberately close your mind to honest investigation and scientific inquiry.
The purely geodesic interpretation is an irrelevant theory.
Place a ball stationary on the edge of warped space. What force could possibly make it move, if gravity is NOT a force? Why would the ball roll "downhill" if you did not first conceive of a force acting beneath the sheet pulling it downwards? Two balls placed near each other in space ALWAYS come together. So if gravity is not a force, what would cause that stationary ball to begin to move in the first place? The geometric interpretation fails utterly to describe the real world, and can only be applied to previously moving bodies.
But you, you will ignore the violation of cause and effect in order to keep your Fairie Dust geometric interpretation of bent space alive. Without gravity as a force, the ball would never move from its position you placed it in. This is observed nowhere in the entire universe.
The idea of the geodesic interpretation is that the objects are following a straight line in 4D spacetime. They are not following a curve. It may seem to be a curve in 3D space, but space has at least 4 dimensions. Time is the fourth dimension and it has a literal meaning in relativity. You are making the mistake of graphing in only three D space and forgetting that for the universe time is another dimension. Just by "moving" forward in time an object is moving in 4D spacetime. Talk to essentialsaltes for more details.
That's not what I asked. I asked how a stationary object begins to move in space, if gravity is not a force? The geometric interpretation violates cause and effect.
No, you just haven't understood what it's saying.That's not what I asked. I asked how a stationary object begins to move in space, if gravity is not a force? The geometric interpretation violates cause and effect.
So a 'stationary' object is always moving at c through spacetime - c in the time direction and 0 in the spatial directions.
Because c isn't a certain speed through distance, it's a speed through spacetime - don't forget that, per Einstein, space and time are actually one four-dimensional object. To use, an object is stationary, but it's actually moving - it's just moving through time at a rate of one second per second.I'm puzzled by this sentence. It seems Justa asked about "moving in space" and you answered about "moving in spacetime".
"c" is a certain speed over distance (spatial). How/why is an object always moving at c through time?
Because c isn't a certain speed through distance, it's a speed through spacetime - don't forget that, per Einstein, space and time are actually one four-dimensional object. To use, an object is stationary, but it's actually moving - it's just moving through time at a rate of one second per second.
Because c isn't a certain speed through distance, it's a speed through spacetime - don't forget that, per Einstein, space and time are actually one four-dimensional object. To use, an object is stationary, but it's actually moving - it's just moving through time at a rate of one second per second.
Imagine driving in your car along a flat plains. You're travelling at a speed V due East. If you aim your car 22.5° more north so that you drive east-northeast, you're still travelling at V, but your eastward speed is only 0.92xV, and your northward speed is now 0.38xV.
This is what happens to objects in spacetime. Objects never change their speed, they just point more in the space direction. You don't accelerate, so much as your movement is more space-y than time-y (which is why time dilates when you move fast - too much is being taken, as it were).
Of course it's a speed through spacetime, but it's certainly measured as a speed over miles or meters or what have you. Some measure of space.
The speed limit on the freeway is measured in miles per hour (or kph). The concept of speed depends on both space and time.
Well, when we say that 'time is the fourth dimension,' a consequence of that is that nothing is ever 'at rest'. To be at rest, all your coordinates have to remain fixed. But since one of the coordinates is time, and time keeps clicking along, nothing is ever at rest.
Everything is 'moving' in time. The equations of relativity mix space and time, so if we follow an object that is initially at rest in the three spatial coordinates, but still moving in time, then at a later time it may have some motion in space, because it has been 'redirected' by the influence of gravity and how it curves the entire 4 dimensional space-time.
So when we're talking about a stationary object at rest, it seems that has to mean it is at rest in a spatial relation to another object, i.e., my keyboard is at rest on my desk; my lamp is at rest 12 inches from my computer. No?
I don't know, I guess I don't even understand what "rest" means even in 3 spatial dimensions. I realize I and my keyboard are hurtling through space around a galactic center, which is also hurtling through space. Everything is moving. Even if you could exclude the time dimension, you're still right, nothing is ever at rest.
So when we're talking about a stationary object at rest, it seems that has to mean it is at rest in a spatial relation to another object, i.e., my keyboard is at rest on my desk; my lamp is at rest 12 inches from my computer. No?
Is it? Motion through the space part of spacetime is in meters per second, sure, but relativity argues that motion is more general than that. Motion is movement through spacetime, whether it's space-y (meters per second) or time-y (seconds per second).Of course it's a speed through spacetime, but it's certainly measured as a speed over miles or meters or what have you. Some measure of space.
Yes and no. One of the core principles of relativity is, well, the Principle of Relativity - there is no possible experiment that could tell you whether you are at rest or in constant motion. That is, the concept of motion (and therefore 'at rest') is entirely relative - we decide whether an object is at rest or not, and everything else settles around it. We can say how much faster one object is moving than the other, but there is no grand objective reference frame to measure everything against.I don't know, I guess I don't even understand what "rest" means even in 3 spatial dimensions. I realize I and my keyboard are hurtling through space around a galactic center, which is also hurtling through space. Everything is moving. Even if you could exclude the time dimension, you're still right, nothing is ever at rest.
Yes... in space, relative to the desk (and you). It's not at rest through time. If it was moving, it'd see you moving, and thus experiencing time dilation and such.So when we're talking about a stationary object at rest, it seems that has to mean it is at rest in a spatial relation to another object, i.e., my keyboard is at rest on my desk; my lamp is at rest 12 inches from my computer. No?
...or time-y (seconds per second).
Yes and no. One of the core principles of relativity is, well, the Principle of Relativity...
That is, the concept of motion (and therefore 'at rest') is entirely relative - we decide whether an object is at rest or not, and everything else settles around it. We can say how much faster one object is moving than the other, but there is no grand objective reference frame to measure everything against.
Well, yes, but we build you GPS machines, so hush[bless and do not curse], physicists are insane.
Ah, I said velocity is relative, but acceleration is not. I can't say how fast you're moving, but I can certainly say how fast your movement is changing. So if you accelerate, it can be known. And since orbiting the Sun is a form of acceleration, it can be known. That's why geocentrism/heliocentrism isn't a matter of arbitrary choice - even if you define the Earth to be stationary, there's still the Sun's gravity pulling us towards it. Since we've defined the Earth to be stationary, we see the Sun move out from under us, hence we fall forever in a circle - we orbit.Who is this "we"? Just the other day, you said the human mind plays no role in determining physical reality. Now you have me thinking I should become a geocentrist flat-earther.
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