There is a certain blog posted (in Google) in which it proposes that gravity is not any kind of force, or to be specific, it is not a natural attracting force similar to a magnet but rather, "a product or an end result of bodies stretching out in a three-dimensional pattern due the inflationary rate of expansion of the space-time continuum". In this blog, the author assumed that the similar gravitational effect created by a centrifuge used to train astronauts, is the same as to the earth's gravity, giving a rather unconventional proposal that the Earth's surface itself is expanding in a rate of 9.8meters per second per second from its center creating a constant rectilinear acceleration to provide a similar effect as to the centrifuge, the difference is that the centrifugal force is the rotational version of gravity. But to achieve that, all things in the Universe must be continously expanding (or increases in volume) including the spaces in between bodies, implying that, space-time is not curve but it appears curve due to a reason that space-time itself is dynamic. Einstein once admitted that his space-time has the tendency to expand, thinking that the Universe is static and introduced the cosmological constant. But that blog also proposes that the space-time could also be non-static. If space-time is a four-dimensional entity, a dynamic kind of space-time would result an additional dimension - the dimension of "gravitational effect" which is possibly the fifth dimension.

Note: I will first ask permission to BAUT, if it is ok to specify the title of that blog. Thanks

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