Abstract
What if it turns out that we have been stubbornly ignoring a crucial message coming from the unsuccessful attempts to create a theory of quantum gravity - that gravity is not an interaction? This option does not look so shocking when gravity is consistently and rigorously regarded as a manifestation of the non-Euclidean geometry of spacetime. Then it becomes evident that general relativity does imply that gravitational phenomena are not caused by gravitational interaction. The geodesic hypothesis in general relativity and particularly the experimental evidence that confirmed it indicate that gravity is not a physical interaction since particles which appear to interact gravitationally are actually free particles whose motion is inertial (i.e. interaction-free). This situation has implications for two research programs - quantum gravity and detection of gravitational waves. First, the real open question in gravitational physics appears to be how matter curves spacetime, not how to quantize the apparent gravitational interaction. Second, the search for gravitational waves should explicitly take into account the geodesic hypothesis according to which orbiting astrophysical bodies (modelled by point masses) do not radiate gravitational energy since their worldlines are geodesics representing inertial (energy-loss-free) motion.
Vesselin Petkov