Maybe it would help to re-frame the relevant part of the (apparent) argument:<p>Oscillations show up everywhere in nature, and even a pattern as specific as a frequency sweep with ringdown could be the result of many different phenomena. Even if in this case many possible sources have been ruled out, there must be others that we do not know about. Since the only observation we have to go on is the signal (so far), we should remember that the cause implied by the model is contingent on the signal not being one of these unknown sources.<p>Some commentary: Imagining alternative explanations is only half of the work that comes next. Once more of these alternatives are found, we also need new experiments that will be designed to rule them out. It sounds like the space-based interferometers will go a long way toward ruling out potential &quot;terrestrial&quot; factors. And if the same signal is detected in both ground-based and space-based systems that is an even greater step forward.