کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1780155 | 1523798 | 2008 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Spacetime is not just space and time Spacetime is not just space and time](/preview/png/1780155.png)
Our physical intuition usually separates space from time, ignoring the spacetime character of the physical reality. In strongly curved spacetimes this may lead to confusion and paradoxes. I present here two examples: (1) in the non-static cosmological spacetimes with flat space sections, the cosmological expansion of space is a true physical effect. Contrary to what the intuition imagines, it cannot be explained as a motion of matter in a non-expanding flat space. (2) Contrary to intuition, for static spacetimes the mathematically simplest 3+13+1 split is not given by the direct projection as in the standard ADM scheme. The simplest split is defined by a counter intuitive “optical geometry” that redshifts both space and time by the same conformal factor.
Journal: New Astronomy Reviews - Volume 51, Issues 10–12, May 2008, Pages 799–802