- #1

Grav Velocity

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- TL;DR Summary
- Escape velocity determines gravitational time dilation. This implies that gravitational mass is causing space-time to pass over a location at the speed of free fall. This idea unites special relativity and general relativity, make relativity more intuitive and simplifies some time dilation calculations.

The is a question about gravitational time dilation and escape velocity. As others have pointed out, you may use escape velocity to calculate gravitational time dilation in a gravitational field. (Interestingly, you can't use gravity to calculate gravitational time dilation, which makes "gravitational" time dilation kind of a misnomer doesn't it?)

It has also been pointed out that free-fall velocity is equal to escape velocity.

It seems clear that it is more than a coincidence that "gravitational" time dilation is determined by escape

I explain this idea in more detail below, but I also created a short video that I think explains it in more detail and include and how you can use the concept of gravitational velocity to perform actual physics calculations.

https://youtu.be/TB6eQZlDhzQ

My idea is that the gravitational mass is causing space-time to fall over a region or object at the free fall velocity and this free falling space-time is what is causing the time-dilation at that location.

That is, in a gravitational field space-time is falling into the gravity well at the free-fall speed and that is causing the time dilation for a particular location, not the gravity itself.

To illustrate

Special Relativity: object move through space at speed v. Time dilation is calculated as √1-v2/c2 (lorentz transform)

----x---->

-----x--->

------x-->

General Relativity: space moves over object at speed v, where v is the accumulated free fall velocity for that location.

| | |

| x |

| | |

V V V

You can also. calculate time dilation as √1-v2/c2 in this case.

Has anyone ever made this observation or argument? It is actually similar to the application of flux in Maxwell's equations.

To rephrase, it is gravitational mass induced spacetime velocity (gravitational velocity) that is causing the time dilation. This is in contrast to gravity itself, which is measured in m/s^2 (acceleration) and which cannot be used to calculate gravitational time dilation on its own. If you just know the gravity at a location you cannot calculate gravitational acceleration.

Again, "gravitational" time dilation is a complete misnomer.

If nothing else, this idea makes the concept of time dilation in general relativity & special relativity much easier to understand and does a better job of connecting the two. It is just a function of the space-time velocity being experienced at either reference frame and you can use the same equation to calculate time dilation.

To me, something must be accumulating (integrating) speed over the length of the gravity well since that is the only way to explain how two locations that experience the same amount of gravity could have different amounts of time dilation. Saying that space-time gathers that velocity makes the most sense. I know this is also called gravitational potential, but that term does not provide much intuitive understanding as to what is happening or how special relative and general relativity are related in this case does it?

Alternatively, you could argue that movement through space-time causes a curvature of that space time that is the equivalent to the curvature caused by a particular mass at a particular distance. This seems even less useful and intuitive, however.

I think the position that there are two different mechanisms for space time dilation (one for special relativity and one for general relativity) is rather dubious as well, particularly when there is are easily calculated velocity values so readily available.

I would be curious as to what are the arguments against this way of viewing "gravitational" time dilation.

It has also been pointed out that free-fall velocity is equal to escape velocity.

It seems clear that it is more than a coincidence that "gravitational" time dilation is determined by escape

__velocity__(or free fall velocity), especially when velocity is what determines time dilation for special relativity.I explain this idea in more detail below, but I also created a short video that I think explains it in more detail and include and how you can use the concept of gravitational velocity to perform actual physics calculations.

https://youtu.be/TB6eQZlDhzQ

My idea is that the gravitational mass is causing space-time to fall over a region or object at the free fall velocity and this free falling space-time is what is causing the time-dilation at that location.

That is, in a gravitational field space-time is falling into the gravity well at the free-fall speed and that is causing the time dilation for a particular location, not the gravity itself.

To illustrate

Special Relativity: object move through space at speed v. Time dilation is calculated as √1-v2/c2 (lorentz transform)

----x---->

-----x--->

------x-->

General Relativity: space moves over object at speed v, where v is the accumulated free fall velocity for that location.

| | |

| x |

| | |

V V V

You can also. calculate time dilation as √1-v2/c2 in this case.

Has anyone ever made this observation or argument? It is actually similar to the application of flux in Maxwell's equations.

To rephrase, it is gravitational mass induced spacetime velocity (gravitational velocity) that is causing the time dilation. This is in contrast to gravity itself, which is measured in m/s^2 (acceleration) and which cannot be used to calculate gravitational time dilation on its own. If you just know the gravity at a location you cannot calculate gravitational acceleration.

Again, "gravitational" time dilation is a complete misnomer.

If nothing else, this idea makes the concept of time dilation in general relativity & special relativity much easier to understand and does a better job of connecting the two. It is just a function of the space-time velocity being experienced at either reference frame and you can use the same equation to calculate time dilation.

To me, something must be accumulating (integrating) speed over the length of the gravity well since that is the only way to explain how two locations that experience the same amount of gravity could have different amounts of time dilation. Saying that space-time gathers that velocity makes the most sense. I know this is also called gravitational potential, but that term does not provide much intuitive understanding as to what is happening or how special relative and general relativity are related in this case does it?

Alternatively, you could argue that movement through space-time causes a curvature of that space time that is the equivalent to the curvature caused by a particular mass at a particular distance. This seems even less useful and intuitive, however.

I think the position that there are two different mechanisms for space time dilation (one for special relativity and one for general relativity) is rather dubious as well, particularly when there is are easily calculated velocity values so readily available.

I would be curious as to what are the arguments against this way of viewing "gravitational" time dilation.