So, . . where do we go out ? ==. If we go out of mass then it can be only one possibility - - we will enter into an empty space. ==. ? A world without masses, without electrons, without an electromagnetic field is an empty world. Such an empty world is flat. But if masses appear, if charged particles appear, if an electromagnetic field appears then our world becomes curved. Its geometry is Riemannian, that is, non- Euclidian.? / Book ?Albert Einstein? The page 116 . by Leopold Infeld. / ===.