Space time?

Question

http://www.math.gatech.edu/~berglund/GR.html

Please click on above source and answer the following questions please.

Why one always thinks of an objects sunken into space (curvature of space) in horizontal plan? Position of earth (or celestial bodies) in its orbit w.r.t to sun is always presented in horizontal plane. WHY? It could be in vertical or inclined plane wrt sun??????
Are we going towards past along with time dimension when earth changes its position for its seasons in its orbit? If it revolves like a spiral then time dimension should be spiral and what are factors that make it spiral?
What is substantial wake effects of these lines after straightening up on earth’s velocity in its orbit and how much is the on coming resistance due to these line that have to depressed?
Similarly can I see my future fiancé (I don’t know who she is) and my past with a powerful telescope (ideal) from galactic centre or any other point far from our galaxy?

Answer 1

The diagrams are an artifice to help clarify how objects would move in curved space. They are shown horizontal so that the object would be acted on by vertical gravity while confined to the embedded space-time shape. It is only good as an analogy and does not represent any real image of spacetime. Space time is four dimensional, and cannot be drawn or imagined. However, the four-dimensional space time can be "viewed" from the "outside" if it is embedded in a five-dimensional space. That doesn't really help, so instead we reduce the number of dimensions to two and imagine it embedded in three dimensions, which we can draw and visualize.

Objects in motion trace out a path in spacetime called the "world line", and you can imagine that past, present and future all exist "at once". However, "at once" is a time concept and does not apply, since time is one of the dimensions.

Your ability to get information from any part of space time is restricted by the limiting velocity of light (light cone) and this prevents you from getting information from the future.

Answer 2

the unit that we call as time does not exist in universe ! sorry- i will not elaborate it. so the diagrams turn out to be invalid !
the scientists are not in position to give the details of universe, forget the "BigBang" ! this is never possible ! ! they just give one or the other theory abt it !
Mahesh / MSc / India.

Answer 3

I guess