DarwinX wrote:You can't curve space because space is 3 dimensional. You can only curve a 2 dimensional plane or line within space. The concept of curved space-time is logically impossible, because no one has every seen or produced 3 dimensional curved space which surrounds a sphere object such as a planet or sphere. This is why, whenever you see a demonstration of curved space time, they always use a 2 dimensional curve around a 3 dimensional sphere to demonstrate it. It's a load of nonsense, in other words.
If you want to speak in absolutes, space is not 3 dimensional. It has more than three dimensions. I personally say six but current string theory says 11 or so. Space appears to have only three dimensions because our psychic apparatus can only deal with three dimensions of space, not 5 or 7.
'Space' is not absolute. You can imagine a two dimensional 'space', the 'space' of a being living within a plane, for example. You can also imagine one dimensional 'space' --- the 'space of a being living within a line. We can even imagine 'zero dimensional space --- the point. Our direct perception of space simply is limited to three dimensions because of the limitations of our perceptive and cognitive apparatuses.
So... we can indeed imagine curving one dimensional 'space'. We can imagine a line curving as it travels through two or three dimensional space. We can also visualize curving a plane. A plane can curve as long as there exists
one dimension higher in which it exists. We can bend the plane because there is another dimension one above it
in which it exists. And if we draw a line on a sheet of paper, we can make it curve because it exists
within a two dimensional world, the sheet of paper. So we can always curve a given 'space'
if there is one dimension higher than it in which it exists. If we assume there is no higher dimension in which it is contained, then no, it does not make any sense to talk about curving a 'space' when it exists in no higher dimension of space. The next higher dimension of space allows for curvature.
Now we can extrapolate this idea to our three dimensional space. We can curve it if it indeed exists within four dimensional space, which it does. However, being able to
visualize this curvature implies, as in the above examples, can we can also visualize it existing in one dimension higher. We can easily visualize two dimensional space curving because we can easily visualize it existing within three dimensional space. For us to be able to visualize three dimensional space curving, we have to be able to visualize it as existing
within a four dimensional space, and as you have pointed out, this is very difficult.
The reason for this is because four dimensional space is what we perceive and cognize as
chronological time. We don't perceive or cognize it as a spatial phenomena
at all. Instead, we perceive it as 'before, now, and after'. 'Yesterday, today, and tomorrow'. So being able to visualize and model three dimensional space curving entails us being able to turn the phenomenon of 'before, now, and after' into something more like 'here and there'. To 'turn time into space' as it were. To be able to visualize time as a higher dimension of space, in which our entire three dimensional space is contained, rather than cognizing it as something chronological.
