The doctrine that at least certain ideas (e.g., those of God, infinity, substance) must be innate, because no satisfactory empirical origin of them could be conceived, flourished in the 17th century and found in RenÃ© Descartes its most prominent exponent.
Local Curvature of Space. According to Einsteinâs theory of general relativity, massive objects warp the spacetime around them, and the effect a warp has on objects is what we call gravity. So, locally, spacetime is curved around every object with mass. Overall Curvature of Space
The orbital period is the time taken for a given object to make one complete orbit around another object. When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars. There are several kinds of orbital periods for objects around the Sun (or other celestial objects): 1  The sidereal period is the temporal cycle that it takes an object to make a full orbit, relative to the stars. 2  This is the orbital period in an inertial (non-rotating) frame of reference.