  Whether the space-time is curved or not? The experimental criterions to judge
this point are: (1) The results of three classical relativistic experiments in
essence are favorable to the special relativistic gravitational theory (base in
the flat space-time). However they are unfavorable to the general relativity.
(2) In the Gravity Probe-B experiment: the gyroscope precession rate of the
orbital effect deduced from the special relativistic gravitational theory
=(2/3)* the precession rate of geodetic effect deduced from the general
relativity, the precession rate of the earth rotation effect deduced from the
special relativistic gravitational theory =(3/2)* the square of cos(phi)* the
precession rate of the frame-dragging effect deduced from the general
relativity, where (phi) is the angle between the projection of gyroscope
angular velocity in the equatorial plane and the normal line of orbital plane.
If the experimental values are identical with the predictive values deduced
from the special relativistic gravitational theory, then the space-time is
flat.
