OK, let's take this by parts. First, gravity as we feel it *is* an acceleration caused by the force, commonly called the gravitational force, which is an attractive force between two objects dependent on their respective masses and the distance between them. Newton wrote it out as F = G*m1*m2/r^2
Second, there are other types of acceleration. The one we see all the time is the electromagnetic acceleration of charged particles which produces the images we see on our computer screens, TV screens, cellphone screens, etc... All accelerations are caused by some kind of physical force. The four known physical forces acting in our universe are gravitation, the electromagnetic force, and the two nuclear forces, which only manifest at sub-atomic distances. Those two are the strong and weak nuclear forces, and about 20 years ago some of the bright sparks out at Fermilab showed that the weak nuclear force split off from the electromagnetic force way back when the universe was a few seconds old.
The rubber sheet model of gravitation and spacetime comes from General Relativity, where Einstein gave us the rubber sheet to illustrate Reimannian geometry, where the surfaces are not necessarily flat. In Reimannian geometry, the dimensions are not defined by the x,y,z unit vectors you're familiar with from regular Euclidian geometry. Rather, the dimensions are defined by surface differentials (the basic form of derivatives) which are orthogonal to each other. So the Euclidian unit vectors are a special case in the classical limit where spacetime is not warped by the presence of mass. When a mass is placed into the spacetime manifold, the manifold warps with the amount of warping proportional to the mass. This warping induces a curvature and the curvature can be measured by changes in the unit differentials.
Which (finally) brings us to your core question: what if gravitation happens because our three-dimensional space is accelerating along an axis perpendicular to all of our spacial dimensions?
The answer is, no, gravitation is not caused by that. General Relativity is a very, very, very well tested theory of gravitation most recently confirmed by the Gravity Probe B results.
Now, the three spatial dimensions we perceive are indeed all perpendicular (or orthogonal) to the time axis. This is most obvious in the Special Relativistic case of a "flat" spacetime manifold (without any mass) where the unit vectors are x, y, z, and -t. (If you want to know why the minus sign has to be there, just ask.) But we're not accelerating along the time axis. The time axis is, itself, an integral part of the spacetime manifold. Time dilation happens if we move very fast in the spatial dimensions, but time dilation is a localized phenomenon limited to the small volume of spacetime that's been accelerated in the spatial dimensions. It's not an acceleration of the spatial matrix relative to the time axis.
no subject
Second, there are other types of acceleration. The one we see all the time is the electromagnetic acceleration of charged particles which produces the images we see on our computer screens, TV screens, cellphone screens, etc... All accelerations are caused by some kind of physical force. The four known physical forces acting in our universe are gravitation, the electromagnetic force, and the two nuclear forces, which only manifest at sub-atomic distances. Those two are the strong and weak nuclear forces, and about 20 years ago some of the bright sparks out at Fermilab showed that the weak nuclear force split off from the electromagnetic force way back when the universe was a few seconds old.
The rubber sheet model of gravitation and spacetime comes from General Relativity, where Einstein gave us the rubber sheet to illustrate Reimannian geometry, where the surfaces are not necessarily flat. In Reimannian geometry, the dimensions are not defined by the x,y,z unit vectors you're familiar with from regular Euclidian geometry. Rather, the dimensions are defined by surface differentials (the basic form of derivatives) which are orthogonal to each other. So the Euclidian unit vectors are a special case in the classical limit where spacetime is not warped by the presence of mass. When a mass is placed into the spacetime manifold, the manifold warps with the amount of warping proportional to the mass. This warping induces a curvature and the curvature can be measured by changes in the unit differentials.
Which (finally) brings us to your core question: what if gravitation happens because our three-dimensional space is accelerating along an axis perpendicular to all of our spacial dimensions?
The answer is, no, gravitation is not caused by that. General Relativity is a very, very, very well tested theory of gravitation most recently confirmed by the Gravity Probe B results.
Now, the three spatial dimensions we perceive are indeed all perpendicular (or orthogonal) to the time axis. This is most obvious in the Special Relativistic case of a "flat" spacetime manifold (without any mass) where the unit vectors are x, y, z, and -t. (If you want to know why the minus sign has to be there, just ask.) But we're not accelerating along the time axis. The time axis is, itself, an integral part of the spacetime manifold. Time dilation happens if we move very fast in the spatial dimensions, but time dilation is a localized phenomenon limited to the small volume of spacetime that's been accelerated in the spatial dimensions. It's not an acceleration of the spatial matrix relative to the time axis.
Clear as mud?