the news media has published the fact that there has thus far been no detection of gravitational waves as predicted by GR. eg Parkes Pulsar Timing Array found nothing after 11 years. If there are no gravitational waves, then GR is wrong. a common argument for gravitons is that there are gravitational waves so there must be gravitons due to wave particle duality how would gravity, GR, strings, loops, QG be modified if there are no gravitational waves as the non-detection thus far have found? are there any alternative gravity theories that pass all tests of classical GR but no gravitational waves?