# The cause of spacetime and gravity

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Does a large amount of mass in a 'small' area cause spacetime to bend inwards to the centre of mass?

If so:
Since the path of light changes because it is travelling with the bent spacetime, why wouldn't other moving particles also bend their path while moving in a bent spacetime? So if it is possible that this bend in spacetime causes particles that are always in motion (such as gases) to bend their path towards the centre of mass, causing gases to stay on Earth. So with this, instead of gravity pulling us down, it's just buoyancy/density + the curved path of spacetime directing motion towards the centre of earth that causes what feels like gravity. With this model, we can explain simple things such as how a bicycle works and why shower curtains blow inwards.

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With this model, we can explain simple things such as how a bicycle works and why shower curtains blow inwards.
Now THAT would be something!!

Some of your questions strongly indicate a need for more reading and understanding before answers are attempted. Be patient, it even took an Einstein some time to understand relativity.

On the other hand, you are on the right track here:

Since the path of light changes because it is travelling with the bent spacetime, why wouldn't other moving particles also bend their path while moving in a bent spacetime?
It was a great confirmation of Einstein's ideas when observations made during an eclipse of the sun indicated light was in fact curved as it passed by the sun. Nobody was sure about that before Einstein's theory. On the other hand, it was already pretty well understood that massive particles [meaning any particles with mass] would be subject to gravity.

A key idea is that unlike the three other forces, EVERYTHING is subject to gravity: Anything with mass or energy [or pressure or even stress] follows Einstein's formulation. Even gases. Even space and time. For example, gas particles [like hydrogen atoms, for example] of the early universe coalesced due to gravity and eventually formed suns, planets, [the earth included] and galaxies and even black holes. And we continue to observe all that happening today.

victorhugo
PeterDonis
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With this model, we can explain simple things such as how a bicycle works and why shower curtains blow inwards.
These things have nothing to do with GR and are off topic here. (I have moved the subthread on this to a new thread in General Physics.)

The model proposed in your OP (if we leave out the speculative analogy with buoyancy, etc.) is not a different model of gravity from GR; it is the model of gravity used in GR. In GR, what we call "gravity" is due to curved spacetime "bending" the paths of things. (This is just a quick heuristic description, of course, but it serves to get across the basic idea.) So GR already does what you propose.